[Search for users] [Overall Top Noters] [List of all Conferences] [Download this site]

Conference 7.286::space

Title:Space Exploration
Notice:Shuttle launch schedules, see Note 6
Moderator:PRAGMA::GRIFFIN
Created:Mon Feb 17 1986
Last Modified:Thu Jun 05 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:974
Total number of notes:18843

952.0. "STS-75 (Columbia)" by ERMTRD::CLIFFE (I'll warp my own space-time ...) Wed Nov 08 1995 03:36

    
    STS-75
    
    Crew:
    
       Andrew M. Allen, 	Commander 
       Scott J. Horowitz, 	Pilot 
       Franklin R. Chang-Diaz 	(Payload Commander) 
       Maurizio Cheli, 		Mission Specialist (ESA) 
       Jeffrey A. Hoffman, 	Mission Specialist 
       Claude Nicollier, 	Payload Specialist (ESA) 
       Umberto Guidoni, 	Payload Specialist (Italy) 
    
    Payload:
    
       TSS-1R, USMP-03 
    
    
    Launch:
    
       Launch February 15, 1996 12:15pm EST Launch window is 2 hours 30 min
    (ESTIMATED) 
    
    Orbit:
    
       Altitude: 160 nm 
       Inclination: 28.45 degrees 
       Orbits: 
       Duration: 13 days, 16 hours, minutes, seconds. (Estimated) 
    
T.RTitleUserPersonal
Name
DateLines
952.1TROOA::SKLEINNulli SecundusThu Nov 09 1995 14:004
	Re: -1 

	Claude Nicollier is a mission specialist, not payload specialist.
952.2Web access is verrry slow today.....NETCAD::BATTERSBYThu Feb 22 1996 16:233
    Anybody hear if this puppy launched today?
    
    Bob
952.3ERMTRD::CLIFFEI'll warp my own space-time ...Fri Feb 23 1996 03:229
    
    Yep.
    
    Actually saw the launch on CNN. - rare these days to see a launch
     on TV in the UK. - just doesn't grab the news.
    
    NASA seem to be slow in updating their Web pages - are they still
     suffering the Gov. cuts or anything ?? 
    
952.4NASA's PAO office has been cutting staff....NETCAD::BATTERSBYFri Feb 23 1996 11:0510
    I thought I recalled hearing that the different NASA site PAO's
    (public affairs offices), have been quietly shedding themselves
    of staffing, and as a result there are fewer PAO staff left at
    each site to update their web sites. As usual as in any organization
    "down-sizing" the resultant worker-bees to managers ratio becomes
    skewed.
    When I got home, I replayed the launch on my vcr & also got to watch
    the replays on NASA Select early in the evening.
    
    Bob
952.5STS-75 Mission Control Status Report # 1ERMTRD::CLIFFEI'll warp my own space-time ...Fri Feb 23 1996 11:3131
    STS-75 Mission Control Status Report # 1
    5:30 p.m. CST, Thursday, Feb. 22, 1996
    
    Space Shuttle Columbia lifted off on time at 2:18 p.m. CST today,
    beginning a two-week mission of scientific experimentation.
    
    An erroneous reading on some engine performance indicators added some
    temporary excitement to an otherwise normal launch today.  About four
    seconds after liftoff, Shuttle Commander Andy Allen reported that his
    instruments showed that one of the shuttle main engines was operating
    at only 45% of its normal power level.  Flight controllers in Houston
    quickly responded that all engines were performing nominally.  The
    engines throttled as expected about 1 minute into the launch, and
    operated normally all the way to main engine cutoff at 8 and a half
    minutes into the flight.  Engineers will look at data from the launch
    to try to understand the faulty reading.
    
    A brief firing of the orbital maneuvering engines halfway around the
    Earth placed Columbia in its operating orbit on time.  The
    seven-member crew got a go for orbit operations as expected and opened
    the payload bay doors to begin cooling with the radiators.
    
    Just before 5 p.m. Central time, astronauts Claude Nicollier and
    Franklin Chang-Diaz begin activating the support equipment for the
    Italian Tethered Satellite System.  Other equipment and experiments
    were scheduled for their first activation later today.  On Friday,
    activities with the TSS begin in earnest leading up to Saturday's
    reeling out of the tethered satellite.
    
    Our next report will be issued Friday morning.
    
952.6STS-75 Mission Control Center Status Report # 2ERMTRD::CLIFFEI'll warp my own space-time ...Fri Feb 23 1996 11:3142
    STS-75 Mission Control Center Status Report # 2
    
    Friday, February 23, 1996, 7 a.m. CST
    
      Setting up shop was the order of business aboard Columbia overnight
    and early Friday as the seven astronauts split into three shifts to
    support the many experiments scheduled throughout the 14-day mission.
    
      Much of the astronauts' time was spent verifying the health of the
    Tethered Satellite System in anticipation of its scheduled deployment
    Saturday afternoon.  The 1,400 pound satellite will be deployed to a
    distance of almost 13 miles while it remains attached to its support
    structure in the orbiter's payload bay by a pencil-thin cable. TSS
    deployment is currently scheduled for Saturday at 2:37 p.m. Central
    time.
    
      Before turning in for his first on-orbit sleep period, Mission
    Specialist Jeff Hoffman tested the latching mechanisms that secure the
    satellite atop its docking ring on an extendable boom structure.
    These latches will be released just prior to the start of the six hour
    process to reel out the satellite.
    
      The crew also checked out and activated several other experiments
    that
    will be carried out after the Tethered Satellite is retrieved Monday.
    A glovebox device on the middeck was set up and will be used later in
    the flight to conduct combustion experiments in an enclosed
    environment.
    
      The astronauts also activated the Commercial Protein Crystal Growth
    experiment designed to grow nearly perfect crystals for study back on
    Earth for the possible development of better pharmaceuticals.
    
      Columbia will remain in a near circular 160 nautical mile orbit for
    most of the mission, circling the Earth every 90 minutes to provide
    the crew with views of a sunrise and sunset 16 times each day.
    
      The Johnson Space Center newsroom will be open from 6 a.m. to 5
    p.m. Friday and will reopen at 8 a.m. Saturday.
    
    
    
952.7STS-75 NASA Select TV scheduleNETCAD::BATTERSBYFri Feb 23 1996 13:14365
Article: 42955
Newsgroups: sci.space.shuttle
From: [email protected] (mary-frances  jagod)
Subject: STS-75: NASA Select TV schedule, Revision A
Sender: [email protected] (News Administrator)
Organization: The University of Chicago
Date: Thu, 22 Feb 1996 23:19:42 GMT
 
[Downloaded from NASA Spacelink]
 
*********************************************************************** 
 
                             NASA TV SCHEDULE 
                           STS-75/TSS-1R/USMP-3 
                                 Rev A 
                                2/22/96 
 
*********************************************************************** 
 
 
NASA TV programming can be accessed through GTE Spacenet 2, 
transponder 5.  The frequency is 3880 MHz with an orbital position 
of 69 degrees West Longitude, with audio at 6.8 MHz.  This is a full 
transponder service and will be operational 24 hours a day. 
 
This NASA Television schedule of mission coverage is available 
on Comstore, the mission TV schedule computer bulletin board service. 
Call 713/483-5817 and follow the prompts to access this service. 
The schedule is also available via the Internet.  The address is 
FTP.HQ.NASA.GOV.  Change directories to /PUB/PAO/STATRPT/JSC/TVSKED. 
 
******************************************************************** 
 
                   ******PROGRAMMING NOTE****** 
 
During the STS-75 mission, there will be Public Affairs commentary 
available on NASA Television 24 hours around the clock through the 
completion of Tethered Satellite operations.  Beginning on flight day 6 
Public Affairs commentary will be available on NASA Television from 
5am CST to 11pm CST.  There will be no commentary from 11pm CST to 
5am CST even though science operations will continue onboard Columbia. 
Public Affairs commentary will resume overnight, however, if 
developments warrant.  Downlink television from Columbia, Earth views 
and programming information will continue to be carried on NASA 
Television during the period the Public Affairs console is unstaffed. 
 
 
   -----  Launch occurred at 2:18pm CST on February 22, 1996  ----- 
           * Asterisk denotes change from previous schedule 
 
 
-------------------------- Thursday, February 22 ---------------------- 
                                   FD 1 
ORBIT            SUBJECT                  SITE       MET        CST 
-----            -------                  ----       ---        --- 
2      NASA TELEVISION ORIGINATION        KSC     00/01:12    03:30 PM 
       SWITCHED TO KSC 
 
2      POST LAUNCH PRESS CONFERENCE       KSC     00/01:12    03:30 PM 
 
2      NASA TELEVISION ORIGINATION        JSC     00/02:12    04:30 PM 
       SWITCHED TO JSC 
 
3      "MISSION UPDATE"                   JSC     00/03:12    05:30 PM 
 
4    * DELTA/POLAR PRE-LAUNCH             VAN     00/04:12    06:30 PM 
       NEWS CONFERENCE REPLAY 
 
4    * Ku BAND ANTENNA DEPLOY                     00/04:30    06:48 PM 
       (not televised) 
 
4      NASA TELEVISION ORIGINATION        KSC     00/05:12    07:30 PM 
       SWITCHED TO KSC 
 
4      LAUNCH ENGINEERING REPLAYS         KSC     00/05:12    07:30 PM 
       T=30:00 
 
4      NASA TELEVISION ORIGINATION        JSC     00/05:42    08:00 PM 
       SWITCHED TO JSC 
 
5      FLIGHT DAY VIDEO FILE              JSC     00/06:12    08:30 PM 
 
--------------------------Friday, February 23 ------------------------- 
                                 FD 2 
9    * DELTA/POLAR PRE-LAUNCH             VAN     00/13:12    03:30 AM 
       NEWS CONFERENCE REPLAY 
 
10   * DELTA/POLAR COVERAGE BEGINS        VAN     00/13:42    04:00 AM 
 
11   * DELTA/POLAR LAUNCH                 VAN     00/15:05    05:23 AM 
 
11     TSS OPERATIONS                     TDRW/E  00/15:50    06:08 AM 
       T=45:00 
 
12   * DELTA/POLAR POST LAUNCH            VAN     00/17:12    07:30 AM 
       PRESS CONFERENCE 
 
 
 
14     "MISSION UPDATE"                   JSC     00/20:42    11:00 AM 
 
16     MISSION STATUS BRIEFING            JSC/    00/22:42    01:00 PM 
                                          MSFC 
 
16     FLIGHT DAY VIDEO FILE              JSC     00/23:42    02:00 PM 
 
------------------------ Saturday, February 24 ------------------------ 
                                 FD 3 
30     "MISSION UPDATE"                   JSC     01/20:42    11:00 AM 
 
32     TSS OPERATIONS                     TDRW/E  01/22:30    12:48 PM 
       T=52:00 
 
33     TV OPPORTUNITY                     MILA    02/00:14    02:32 PM 
       T=9:00 
 
33   * TSS FLYAWAY                        TDRW    02/00:20    02:38 PM 
       (may not be televised live) 
 
34     TV OPPORTUNITY                     MILA    02/01:43    04:01 PM 
       T=6:00 
 
34     TV OPPORTUNITY                     GDS     02/01:53    04:11 PM 
       T=7:00 
 
34     MISSION STATUS BRIEFING            JSC     02/02:12    04:30 PM 
       (time subject to change) 
 
35     FLIGHT DAY VIDEO FILE              JSC     02/03:12    05:30 PM 
 
------------------------- Sunday, February 25 ------------------------- 
                                 FD 4 
46     TV OPPORTUNITY                     MILA    02/19:35    09:53 AM 
       T=8:00 
 
46     "MISSION UPDATE"                   JSC     02/20:42    11:00 AM 
 
48   * CBS RADIO INTERVIEW                TDRE    02/22:45    01:03 PM
       (audio only) 
 
48     MISSION STATUS BRIEFING            JSC/    02/23:12    01:30 PM 
                                          MSFC 
 
49     FLIGHT DAY VIDEO FILE              JSC     03/00:12    02:30 PM 
 
------------------------- Monday, February 26 ------------------------- 
 
62     TV OPPORTUNITY                     MILA    03/19:43    10:01 AM 
       T=6:00 
 
62     "MISSION UPDATE"                   JSC     03/20:42    11:00 AM 
 
63     TSS DOCKING OPERATIONS             TDRE    03/21:20    11:38 AM 
       T=23:00 
 
63     TSS DOCKING OPERATIONS             TDRE    03/21:52    12:10 PM 
       T=8:00 
 
63   * TSS DOCKING                        TDRW    03/22:28    12:46 PM 
       (may not be televised) 
 
64     TSS BOOM RETRACT & SRL LATCH       TDRE    03/22:55    01:13 PM 
       T=17:00 
 
65     MISSION STATUS BRIEFING            JSC/    04/00:12    02:30 PM 
       (time subject to change)           MSFC 
 
65     VTR DUMP - TSS RETRIEVAL           TDRE    04/00:20    02:38 PM 
       T=25:00 
 
65     FLIGHT DAY VIDEO FILE              JSC     04/01:12    03:30 PM 
 
71     VTR DUMP - TSS OPERATIONS          TDRW    04/09:30    11:48 PM 
       T=30:00 
 
------------------------ Tuesday, February 27 ------------------------- 
                                 FD 6 
78     "MISSION UPDATE"                   JSC     04/20:42    11:00 AM 
 
80   * CNN INTERVIEW                      TDRW    04/22:40    12:58 PM 
 
80     MISSION STATUS BRIEFING            JSC/    04/23:12    01:30 PM 
                                          MSFC 
 
81     FLIGHT DAY VIDEO FILE              JSC     05/00:12    02:30 PM 
 
83   * CONUS INTERVIEW                    TDRW    05/03:35    05:53 PM 
 
------------------------ Wednesday, February 28 ----------------------- 
                                  FD 7 
91   * C-SPAN INTERVIEW                   TDRW    05/16:25    06:43 AM 
 
94     "MISSION UPDATE"                   JSC     05/20:42    11:00 AM 
 
96     MISSION STATUS BRIEFING            JSC/    05/22:42    01:00 PM 
                                          MSFC 
 
96     SPACE SCIENCE UPDATE               HQ      05/23:42    02:00 PM 
 
97     FLIGHT DAY VIDEO FILE              JSC     06/00:42    03:00 PM 
 
101  * VTR DUMP - FFFT                    TDRW    06/06:45    09:03 PM 
       T=30:00 
 
------------------------ Thursday, February 29 ------------------------ 
                                  FD 8 
110    "MISSION UPDATE"                   JSC     06/20:42    11:00 AM 
 
111    MISSION STATUS BRIEFING            JSC/    06/22:42    01:00 PM 
                                          MSFC 
 
112    VTR DUMP - CSD                     TDRW    06/22:55    01:13 PM 
       T=25:00 
 
112    FLIGHT DAY VIDEO FILE              JSC     06/23:42    02:00 PM 
 
114  * WPHL-TV/WPVI-TV INTERVIEW          TDRW    07/02:02    04:20 PM 
 
115  * USIA WORLDNET INTERVIEW            TDRW    07/03:50    06:08 PM 
 
-------------------------- Friday, March 1 ---------------------------- 
                                 FD 9 
126  * ITALIAN MEDIA INTERVIEW            TDRW    07/19:50    10:08 AM 
 
126  * VTR DUMP - CSD                     TDRE    07/20:20    10:38 AM 
       T=20:00 
 
126    "MISSION UPDATE"                   JSC     07/20:42    11:00 AM 
 
127  * ITALIAN ASI VIP EVENT              TDRW    07/21:25    11:43 AM 
 
127    MISSION STATUS BRIEFING            JSC/    07/22:12    12:30 PM 
                                          MSFC 
 
128    FLIGHT DAY VIDEO FILE              JSC     07/23:42    02:00 PM 
 
129  * ESA SWISS EDUCATIONAL EVENT        TDRW    08/00:30    02:48 PM 
 
131  * VTR DUMP - RITSI                   TDRW    08/03:35    05:53 PM 
       T=40:00 
 
------------------------- Saturday, March 2 --------------------------- 
                                FD 10 
141  * VTR DUMP - FFFT                    TDRE    08/18:50    09:08 AM 
       T=30:00 
 
142    "MISSION UPDATE"                   JSC     08/20:42    11:00 AM 
 
143    MISSION STATUS BRIEFING            JSC/    08/22:42    01:00 PM 
                                          MSFC 
 
144    FLIGHT DAY VIDEO FILE              JSC     08/23:42    02:00 PM 
 
146  * NBC SPANISH NEWSCHANNEL/          TDRW    09/02:15    04:33 PM 
       CNN INTERNATIONAL INTERVIEW 
 
147  * VTR DUMP - CSD                     TDRW    09/03:45    06:03 PM 
       T=40:00 
 
-------------------------- Sunday, March 3 ---------------------------- 
                                FD 11 
156  * VOICE OF AMERICA INTERVIEW         TDRW    09/18:25    08:43 AM 
 
157  * VTR DUMP - RITSI                   TDRW    09/19:45    10:03 AM 
       T=40:00 
 
158    "MISSION UPDATE"                   JSC     09/20:42    11:00 AM 
 
159    MISSION STATUS BRIEFING            JSC/    09/22:42    01:00 PM 
                                          MSFC 
 
160    FLIGHT DAY VIDEO FILE              JSC     09/23:42    02:00 PM 
 
162  * VTR DUMP - CSD                     TDRW    10/02:20    04:38 PM 
       T=35:00 
 
166  * VTR DUMP - FFFT                    TDRW    10/08:55    11:13 PM 
       T=25:00 
 
-------------------------- Monday, March 4 ---------------------------- 
                                FD 12 
170  * ESA ITALIAN EDUCATIONAL EVENT      TDRW    10/15:25    05:43 AM 
 
174    "MISSION UPDATE"                   JSC     10/20:42    11:00 AM 
 
175    MISSION STATUS BRIEFING            JSC/    10/22:42    01:00 PM 
                                          MSFC 
 
176    FLIGHT DAY VIDEO FILE              JSC     10/23:42    02:00 PM 
 
176  * VTR DUMP - RITSI                   TDRE    10/23:56    02:14 PM 
       T=26:00 
 
-------------------------- Tuesday, March 5 --------------------------- 
                                FD 13 
184  * VTR DUMP - FFFT                    TDRE    11/11:05    01:23 AM 
       T=30:00 
 
185  * VTR DUMP - CSD                     TDRE    11/12:45    03:03 AM 
       T=30:00 
 
187  * CREW NEWS CONFERENCE               TDRE    11/15:45    06:03 AM 
 
190    "MISSION UPDATE"                   JSC     11/20:42    11:00 AM 
 
191    MISSION STATUS BRIEFING            JSC/    11/22:42    01:00 PM 
                                          MSFC 
 
192    FLIGHT DAY VIDEO FILE              JSC     11/23:42    02:00 PM 
 
195  * UNIVISION/TELENOTICIAS INTERVIEW   TDRW    12/04:20    06:38 PM 
 
-------------------------- Wednesday, March 6 ------------------------- 
                                 FD 14 
204    MISSION STATUS BRIEFING            JSC     12/18:42    09:00 AM 
 
206    "MISSION UPDATE"                   JSC     12/20:42    11:00 AM 
 
207  * Ku BAND ANTENNA STOW                       12/21:45    12:03 PM 
       (not televised) 
 
207    MISSION SCIENCE BRIEFING           MSFC    12/22:42    01:00 PM 
 
208    FLIGHT DAY VIDEO FILE              JSC     12/23:42    02:00 PM 
 
-------------------------- Thursday, March 7 -------------------------- 
                                 FD 15 
218  * DEORBIT BURN                               13/15:14    05:32 AM 
       (not televised) 
 
219  * KSC LANDING                        KSC     13/16:14    06:32 AM 
 
       LANDING REPLAYS                    KSC           L + 20 minutes 
 
       POST LANDING PRESS CONFERENCE      JSC           L + 60 minutes 
 
       ASTRONAUT POST LANDING PRESS 
       CONFERENCE  (COMMANDER AND OTHER 
       AVAILABLE CREW MEMBERS)            KSC           L +  6 hours 
 
 
*********************************************************************** 
                         DEFINITION OF TERMS 
*********************************************************************** 
 
CSD:      Comparitive Soot Diagnostics 
CST:      Central Standard Time 
FD:       Flight Day 
FFFT:     Forced Flow Flame-Spreading Test 
GDS:      Goldstone Tracking Station 
JSC:      Johnson Space Center 
KSC:      Kennedy Space Center 
MECO:     Main Engine Cut Off 
MET:      Mission Elapsed Time: the time which begins at the moment 
          of launch and is read: days/hours:minutes.  Launch=00/00:00 
MILA:     Merritt Island Tracking Station 
MSFC:     Marshall Space Flight Center 
RITSI:    Radiative Ignition and Transition to Spread Investigation 
STS:      Space Transportation System 
T=:       Time equivalent: used for duration of event 
TDRE,W:   Tracking and Data Relay Satellite, East and West longitudes 
TSS:      Tethered Satellite System 
USMP:     United States Microgravity Payload 
VAN:      Vandenberg Air Force Base
 
952.8FailureDEVLPR::ANDRADEMon Feb 26 1996 10:386
    The tether broke, after it extended almost to max.
    
    Bye-bye mission, it will be a long time before they try anything
    like this again. They failed 4 years ago, and again now...
    
    Gil
952.9CLUSTA::MAIEWSKIBos-Mil-Atl Braves W.S. ChampsMon Feb 26 1996 10:516
  Can't say I'm surprised, those things never work. 

  NASA is always at their worst trying to unwind or release something
mechanical. 

  George
952.10MPGS::REITH[email protected] - Have subroutine, will travel.Mon Feb 26 1996 11:383
I assume it was active during the unreeling so they should have gotten SOME
readings before the break. I haven't seen any reports on it, where in the
tether (which end) did it break?
952.1119472::petertrigidly defined areas of doubt and uncertaintyMon Feb 26 1996 11:474
They did get some data and electricity generated.  The tether disconnected 
at the boom end, after about 12 miles were played out.

PeterT
952.12MPGS::REITH[email protected] - Have subroutine, will travel.Mon Feb 26 1996 12:016
I wondered about that. I seem to remember the mention of a cutting device at
the boom ent to handle the jamming incident of last time and wondered if it
might have misfired due to static from the test. At least they got some more
realistic data. Better than the 600 meters from the last time.

Thanks for the info
952.13Can you say *Boing!* 12 miles long?NETCAD::BATTERSBYMon Feb 26 1996 12:5120
    There was a note I saw in the shuttle newsgroup that said that
    they supposedly got telemetry indicating as much as about 1600 volts 
    (very low current). The camcorder footage they down-linked after
    the break was quite interesting. They had 2 separate cameras focused
    on the tether. One was inside the shuttle, and the other was a camera
    in the payload bay I believe. When the tether broke, the in-cabin
    camcorder showed the tether going slack, and then someone bumped the
    camera. It took them a few seconds to get the camera back into
    position. The Tether acted like a huge rubber band, and must have
    released the energy stored in it and allowed the tether satellite
    to accelerate away from the shuttle. They said it rapidly reached
    a separating velocity of about 85 mph within a very short time.
    It's too bad, but they *are* dealing with experimental situations,
    and things like this can happen with things like this.
    The camcorder closeups they got while doing a visual inventory
    afterwards showed the frayed end of the tether, so it wasn't a
    clean break or cut. More like it was a stressed place in the tether
    where there was a defect.
    
    Bob
952.14next 13 replys are MCSR reportsERMTRD::CLIFFEI'll warp my own space-time ...Thu Feb 29 1996 11:5221
    I have been out of the country the last few days - catching up now !
    
    I managed to see a lot of what happened as the Hotel TV room had CNN.
    
    Re -.1  BOING - exactly what I mentally pictured when I saw the tether
     going of into space.
    Lots of shots of the frayed end - look like it really did tear apart.
    
    Things I have not been able to find out.
    
    How has the (ex)Tethered Satellite managed to get into a higher
       orbit ?
    
    	I thought with the tension breaking in the tether, the Shuttle
          would go one way, the TS the other.
    
    They were also talking about using a pendulum swing to put satellites
     into a higher orbit - how do you get a pendulum swing in such system ?
         
    
    
952.15STS-75 Mission Control Center Status Report # 3ERMTRD::CLIFFEI'll warp my own space-time ...Thu Feb 29 1996 11:5248
STS-75 Mission Control Center 
Status Report # 3

Friday, February 23, 1996, 4:30 p.m. CST

Although running into tethered satellite computer problems that remain
under investigation by flight controllers and scientists,
Columbia's crew pressed ahead this afternoon with checkouts and
preparations for a Saturday deploy of the satellite.

The tethered satellite itself was powered up and appears to be in
excellent condition.  However, activation and checkout of the
satellite-related experiments that are mounted in Columbia's cargo
bay fell behind schedule when a computer relay for data and commands
experienced problems. The Smart Flexible Multiplexer Demultiplexer
(SFMDM), or "Smartflex", as the computer relay is called, was
switched to a backup component after experiencing an apparent overload
when some of the cargo bay experiments were first powered up.

The backup "Smartflex" equipment is working well, but controllers are
evaluating its performance for several hours before attempting to
repower the cargo bay-mounted satellite experiments and put further
demands on the unit. At this point, there is still enough time prior
to Saturday's planned 2:37 p.m. satellite deploy to reactivate
those experiments and perform all needed checkouts and fine-tuning.
Flight controllers currently plan to begin those procedures this
evening aiming toward an on-time satellite flyaway.

In addition to the computer relay trouble, the crew reported apparent
balky processing by an onboard laptop computer used as one method of
displaying information from the satellite experiments. The Portable
General Purpose Support Computer (PGSC) was switched for a backup
laptop computer by the crew, and the data connections to the computer
ports also were switched to backup ports. However, the apparent slow
processing persisted. Flight controllers are evaluating the cause of
the trouble, and any impact it may have on the planned operations.

The "Smartflex" must be operating for a deploy of the tethered
satellite since it provides data and commands to the satellite-related
experiments and equipment in the cargo bay.  Communications and
commanding of the satellite itself during deploy, however, is done by
a radio link to Columbia.

Columbia's systems are functioning well, with virtually no Shuttle
problems encountered by the crew. It remains in a 184-mile-high
circular orbit of Earth.

    
952.16STS-75 Mission Control Center Status Report # 4ERMTRD::CLIFFEI'll warp my own space-time ...Thu Feb 29 1996 11:5354
STS-75 Mission Control Center Status Report # 4

Saturday, February 24, 1996, 8 a.m. CST

Troubleshooting a balky experiment data relay box was the focus of
work aboard Columbia throughout Friday night and into this morning as
the astronauts and flight controllers attempted to track down the
problem and preserve their options for deploying the tethered
satellite at 2:37 this afternoon.

Early this morning, in a methodical step-by-step process, the crew and
flight control team slowly activated several experiments individually
at first and then together trying to isolate the problem.  At about 2
a.m., all experiments were activated and data was being transferred
through the relay box to a laptop computer on the flight deck of the
orbiter and data was transmitted successfully to the ground.  The
computer relay is continuing to perform well and is not evidencing any
of the communications problems previously observed.  Mission Managers
are meeting this morning to review the system's status and make a
determination on whether to deploy TSS on time or to delay 24 hours.

Called a Smart Flexible Multiplexer Demultiplexer, or "Smart Flex"
for short, the relay box reset itself several times and even
switched to an alternate system on occasion when it perceived it was
being overloaded by the checkout work associated with ensuring the
experiments were ready to support Tethered Satellite System
operations.

The relay box is used as a way station for obtaining and distributing
data collected from four science experiments designed to take
measurements during the deployment, on- station, and retrieval
operations of the satellite.  The "Smartflex" must be operating
for a deploy of the tethered satellite since it provides data and
commands to the satellite-related experiments and equipment in the
cargo bay.

Once deployed, the tethered satellite will slowly fly away from
Columbia, eventually reaching a distance of 12 miles (20 kilometers).
Communications and commanding of the satellite itself during deploy
and retrieve is done by a radio link to the Space Shuttle by ground
commands from NASA's Marshall Spaceflight Center in Huntsville,
which has overall program management for the TSS project.

The tethered satellite will slowly be deployed to a 12 mile distance
over a five and a half hour period.  The satellite will remain "on
station" for science operations for about 24 hours.  The retrieval
process would follow with the satellite being reeled back in during
another five and half hour period.

Columbia continues to function with no systems problems at an altitude
of 184 miles, circling the Earth every 90 minutes.


    
952.17STS-75 Mission Control Center Status Report # 5ERMTRD::CLIFFEI'll warp my own space-time ...Thu Feb 29 1996 11:5327
STS-75 Mission Control Center Status Report # 5

Saturday, February 24, 1996, 10:30 a.m. CST

STS-75 mission managers Saturday morning decided to delay deployment
of the Tethered Satellite by 24 hours to give flight controllers time
to gain additional confidence in the operations of a data relay that
provides satellite system information during deploy and science
operations.

The Smart Flex data relay box has been stable since early this
morning, but mission managers wanted additional time to understand its
previously observed behavior.  The relay box had experienced several
unexpected "restarts". It has been performing without incident,
however, since early this morning.

The 24-hour delay also gives flight controllers the opportunity to
enhance any contingency procedures that might be used in the event the
Smart Flex develops problems during the deploy operations.

Late this afternoon, the astronauts will begin a standard
one-day-before-deploy timeline, allowing them to catch up on some
activation steps which were omitted during the compressed timeline
which would have been required if TSS were deployed as originally
scheduled this afternoon.

    
952.18STS-75 Mission Control Center Status Report # 6ERMTRD::CLIFFEI'll warp my own space-time ...Thu Feb 29 1996 11:5344
STS-75 Mission Control Center Status Report # 6

Sunday, February 25, 1996, 8 a.m. CST

  Columbia's crew will begin the deploy sequence of the Tethered
Satellite System about 2:45 this afternoon after a one-day delay to
allow flight controllers and the astronauts additional time to
properly check out the various science instruments and equipment that
will be used throughout the two-day operation.

  The delay also gave flight controllers time to refine any
troubleshooting procedures that might be used in the event the Smart
Flex computer relay system develops problems during the deploy
operations.  The system has been operating trouble-free for more than
24 hours since being systematically checked out early Saturday
morning.

  Prior to initiating the deploy sequence, the boom supporting the
Tethered Satellite will be raised out of the payload bay to a height
of about 39 feet.  The satellite will be released from its docking
ring capture latches at the top of the boom and will slowly and
deliberately be deployed to a distance of slightly more than 12 mile
(20 kilometers) over a five and a half hour period.  The satellite
will remain 'on station' for science operations for about 22
hours.

  Retrieval of TSS would follow with the satellite being reeled back in
during another five and half hour period, stopping for additional
science data gathering at a distance of about one mile from the
Shuttle.  This second 'on station' operation is scheduled to
last for nine hours before the final retrieval and docking of the
satellite.  The entire TSS operation is scheduled to last about 48
hours.

  Communications and commanding of the satellite during deploy and
retrieve is done by a radio link to the Space Shuttle by ground
commands from NASA's Marshall Space Flight Center in Huntsville,
which has overall program management for the TSS project.

  With Columbia's systems in excellent shape, activities today are
focused on the deploy of the Tethered Satellite.  Columbia continues
to circle the Earth every 90 minutes at an altitude of 184 miles.

    
952.19STS-75 Mission Control Status Report # 7ERMTRD::CLIFFEI'll warp my own space-time ...Thu Feb 29 1996 11:5446
STS-75 Mission Control Status Report # 7

6 p.m. Sunday, February 25, 1996

  Three and a half years after an errant bolt halted its deployment, the
Italian Tethered Satellite successfully began its journey from the
Shuttle Columbia for two days of scientific studies.

  Suspended at the end of a slim tether, the satellite's thrusters
nudged TSS away from a docking ring atop a 40-foot boom towering over
Columbia's cargo bay at 2:45 PM Central time. The satellite slowly
moved away from Columbia into the darkness of space as the astronauts
reported little oscillation in the long tether. An hour later, the TSS
had passed the distance of maximum deployment achieved on its previous
flight, 843 feet, during the STS-46 mission in the summer of 1992.

  Astronauts and ground controllers overcame previous difficulties
with data handling equipment and portable computers which had caused a
one-day delay in the deployment.  Operating on a normal timeline
today, the crew checked out the satellite and its associated systems
before extending the TSS boom above the bay like a giant tower.  After
making sure that Columbia and the TSS could communicate over radio
links, a power umbilical to the satellite was released, placing the
satellite on internal battery power. Columbia's maneuvering jets
were temporarily disabled during the TSS deployment, to avoid any
disturbances to the tether during the satellite's initial flyaway.

   TSS is expected to reach its farthest distance from Columbia,
almost 13 miles, by late this evening for more than 24 hours of
scientific studies on electromagnetic phenomena and the use of tethers
for satellite management. The satellite will begin its slow creep back
to Columbia Monday night in advance of its final retrieval and docking
back on its boom at about 12:43 PM Central time Tuesday afternoon.

  Columbia is functioning perfectly in support of TSS operations as it
orbits the Earth every 90 minutes at an altitude of about 180 statute
miles.

  The JSC newsroom will close for the night at 9 p.m. Sunday and will
reopen at 6 a.m.  Monday.





    
952.20STS-75 Mission Control Status Report #8ERMTRD::CLIFFEI'll warp my own space-time ...Thu Feb 29 1996 11:5426
STS-75 Mission Control Status Report #8

9:30 p.m. CST Sunday, February 25, 1996

  The tether on the Italian Tethered Satellite broke about 7:30 p.m. CST
Sunday as the satellite was nearing the full extent of its deployment
from the Shuttle.  The satellite, which was nearing the end of its
planned 12.8 mile distance, immediately began accelerating away from
Columbia at a rapid rate as a result of normal orbital forces.  TSS is
separating from Columbia at a rate of 420 miles each 90 minute orbit.

  The tether apparently snapped near the top of the 39-foot TSS boom
in Columbia's cargo bay.  Neither the astronauts nor the Space
Shuttle were ever in any danger.

  Following the break, Mission Control asked the astronauts to record
television of the boom and broken tether for post-flight analysis.

  Flight controllers now will be determining when and how to secure
the TSS support equipment, including the deployment boom, before
moving on with other mission objectives.  Scientists and engineers
managed to gather about five hours of data on the performance of the
satellite and tether dynamics before the break.


    
952.21STS-75 Mission Control Status Report #9ERMTRD::CLIFFEI'll warp my own space-time ...Thu Feb 29 1996 11:5444
STS-75 Mission Control Status Report #9
10:00 a.m. CST Monday, February 26, 1996

Columbia's astronauts are preparing to retract the Tethered Satellite
boom structure today after the Italian science probe suddenly
seperated from the Shuttle last night following a break in the
tether. The boom tower, upon which TSS was anchored prior to its
deployment Sunday afternoon, will be slowly lowered back into its
berthing platform once the remaining tether inside the boom is reeled
in.

After its connecting cable seperated from Columbia last night, the
Tethered Satellite is trailing the Shuttle at a distance of more than
3,000 nautical miles this morning.

The satellite is in an orbit about 30 miles above Columbia and the
distance between the two spacecraft continues to increase at a rate of
about 280 nautical miles with every orbit of the Earth. At the time
the tether broke, it was extended 12.2 miles from Columbia, just short
of its planned 12.8 mile fully-deployed length.

About 32 feet of tether remains on the reel assembly inside the TSS
support boom in Columbia's payload bay. Once the tether is fully
retracted, the 39-foot boom will be restowed to its launch
configuration.  On Columbia, the astronauts this morning saved TSS
onboard computer data for post-flight analysis.

Once the tether is retracted and the boom is restowed, the crew
members will turn their attention to the science activities involving
the U. S. Microgravity Payload.  The USMP experiments will study
various aspects of materials science investigation.

The astronauts are scheduled to hold a crew news conference today at
2:03 p.m. Central time to discuss the loss of the Tethered Satellite
and other aspects of their flight.

Columbia continues to perform flawlessly, orbiting the Earth every
90 minutes at an altitude of about 180 statute miles.

The JSC newsroom will close at 5 p.m. today and will reopen at 6 a.m. Tuesday.



    
952.22STS-75 Mission Control Status Report #10ERMTRD::CLIFFEI'll warp my own space-time ...Thu Feb 29 1996 11:5440
STS-75 Mission Control Status Report #10
5 p.m. Monday, February 26, 1996

Astronauts aboard Space Shuttle Columbia today reeled back the
remaining length of tether and stowed the mast for the Tethered
Satellite System following last night's loss of the satellite.  The
crew and flight control teams spent much of the day putting TSS
equipment in a safely stowed condition and preparing for experiment
operations with the U.S. Microgravity Payload.

The Italian Satellite unexpectedly separated from Columbia about 7:30
p.m. CST Sunday as the tether broke within the mast. No immediate
explanation for the incident was apparent and the crew and Mission
Control concentrated last night and today on gathering any data that
might be useful in discovering the cause.  NASA today named a board
chairman for the investigative body looking into the incident.
Members to the board are expected to be named within a few days.

Following separation from Columbia Sunday, the satellite moved rapidly
away from the Shuttle into its higher orbit.  The satellite is in an
orbit about 30 miles above Columbia and the distance between the two
spacecraft continues to increase at a rate of about 280 nautical miles
with every orbit of the Earth. At the time the tether broke, it was
extended 12.2 miles from Columbia, just short of its planned 12.8 mile
fully-deployed length.

The crew members will now turn their attention to the science
activities involving the U.  S. Microgravity Payload.  The USMP
experiments will study various aspects of materials science
investigation.

The astronauts held a crew news conference today at 2:03 p.m. Central
time to discuss the loss of the Tethered Satellite and other aspects
of their flight.

The JSC newsroom will close at 5 p.m. today and will reopen at 6
a.m. Tuesday.


    
952.23STS-75 Mission Control Center Status Report # 11ERMTRD::CLIFFEI'll warp my own space-time ...Thu Feb 29 1996 11:5552
STS-75 Mission Control Center Status Report # 11

Tuesday, February 27, 1996, 10 a.m. CST

Columbia's crew is preparing to move into the second major portion
of the STS-75 mission activating the United States Microgravity
Payload, or USMP, after completing work with several experiments
associated with the tethered satellite portion of the flight.

The USMP experiments will gather data on various materials science
investigations including crystal growth, materials solidification and
fluid dynamics.  TSS-related experiments have been operated by the
crew throughout the night gathering data on the orbiter's payload
environment.  Investigations included measuring glow and
electrodynamic phenomena around the orbiter surfaces during thruster
firings.  At about 2:30 this afternoon, the crew will begin shifting
to USMP operations for the remainder of the flight.

In the meantime, tethered satellite payload and ground controllers are
taking snapshots of data from the satellite sending data through
available ground stations around the world.  Commands were scheduled
to be sent directly to the satellite during several passes throughout
the day over Houston as it passed within range of the Electronics
Signal Test Lab at the Johnson Space Center.  Data collection will
continue as long as the TSS batteries remain fuctioning, about 24 - 48
hours.

Initial configuration data received from TSS indicates that the
thruster valves, which were commanded to a closed position as the
satellite was being reeled out from Columbia, are open and that no
gaseous nitrogen remains on board.  Additionally, two of four
stabilizing gyros on the satellite give indications of being in the
"off" position.  This and all other data gathered during dumps
to the ground stations will be gathered for post-flight analysis.

The satellite unexpectedly separated from Columbia about 7:30 p.m. CST
Sunday as the tether broke within the mast.  The latest information on
the satellite shows it trailing Columbia at a distance of 8,500
nautical miles, in an orbit 221 nm by 170 nm.  Columbia remains in an
orbit 30-40 miles lower than the satellite causing the distance
between the two spacecraft to increase by about 350 nm per orbit.

With the TSS operations winding down, the crew will begin
concentrating its attention on the remaining payload activity and
Commander Andy Allen will begin shifting his schedule to match that of
the Red Team of astronauts which includes Pilot Scott Horowitz,
Mission Specialist Maurizio Cheli and Payload Specialist Umberto
Guidoni.  Mission Specialist Jeff Hoffman has shifted his schedule to
match the Blue Team of mission specialists Claude Nicollier and
Franklin Chang-Diaz.

    
952.24STS-75 Mission Control Center Status Report # 12ERMTRD::CLIFFEI'll warp my own space-time ...Thu Feb 29 1996 11:5550
STS-75 Mission Control Center Status Report # 12

Tuesday, February 27, 1996, 5 p.m. CST

Columbia's crew moved into the second major objective of their flight
this afternoon, turning attention to the weightless investigations of
the United States Microgravity Payload-3.

The crew performed further checks this afternoon of the Middeck Glove
Box Experiment, readying the equipment on Columbia's lower deck for
several studies of combustion planned later in the mission. Crew
members this evening will have a light day of activities, each
enjoying a half-day of free time as is customary on two-week long
shuttle flights.

The crew also took a break from today's experiments for interviews
by the Cable News Network and the syndicated Conus Communications
Network.

Earlier today, ground controllers used tracking stations scattered
around the world to receive information from the Tethered Satellite
which broke free from the shuttle on Sunday. Now in an orbit of 219 by
170 nautical miles, experiments on the satellite recorded emissions of
electrons from Columbia's cargo bay, almost half a world away,
scientists reported. Although a variety of ground tracking sites
received transmissions from the satellite, commands were sent to the
satellite only from a ground station at the Johnson Space Center in
Houston. The opportunities for ground contact with the satellite for
today are finished, but controllers plan to attempt further
communications with the satellite during orbital passes tomorrow.

Flight controllers reported that the satellite is orbiting the Earth
in a different configuration that it was in at the time its tether
broke, with its thruster fuel depleted and no ability to receive
commands to deploy its twin science booms. But science officials said
valuable data is being received from TSS regarding the
characterization of electromagnetic fields in low Earth orbit. The
satellite, dragging about 12 miles of tether, is expected to begin to
drop out of orbit sometime in the next 30 days and will burn up in the
atmosphere during its reentry.

Columbia, meanwhile, is functioning to near perfection, with no
mechanical problems of concern to flight controllers. The shuttle is
in a 184 by 177 statute mile orbit of Earth.

The JSC newsroom is now closed and will reopen at 6 a.m. Central time
on Wednesday.

*   *   *
    
952.25STS-75 Mission Control Center Status Report # 13ERMTRD::CLIFFEI'll warp my own space-time ...Thu Feb 29 1996 11:5533
STS-75 Mission Control Center Status Report # 13

Wednesday, February 28, 1996, 7 a.m. CST

With the focus of work aboard Columbia turning to weightless
investigations of the United States Microgravity Payload, flight
controllers in Houston and Huntsville continue to gather as much data
from the tethered satellite as possible before its batteries run out.

USMP experiments are collecting data on various materials science
investigations including crystal growth, materials solidification and
fluid dynamics.

Half of the crew enjoyed a half day of free time as is customary on
two-week long shuttle flights.  During the break, Pilot Scott
Horowitz, Mission Specialist Maurizio Cheli and Payload Specialist
Umberto Guidoni discussed the flight with the C-SPAN network and
answered questions from viewers.

The ground commanding to the tethered satellite began yesterday and is
expected to continue today as it passes within range of the ground
station at the Johnson Space Center.  Payload officials will again
take snapshots of data from the satellite to determine its health
before its batteries completely discharge; this is expected within the
next couple of days.

Columbia, meanwhile, is functioning normally, with no problems of
concern to flight controllers.

The JSC newsroom will close at 5 p.m. today and will reopen at 6 a.m. Thursday.

*   *   *
    
952.26STS-75 Mission Control Center Status Report # 14ERMTRD::CLIFFEI'll warp my own space-time ...Thu Feb 29 1996 11:5639
STS-75 Mission Control Center Status Report # 14

Wednesday, February 28, 1996, 5 p.m. CST

NASA managers decided today not to return Columbia to the Tethered
Satellite for either a close inspection or a possible retrieval after
concluding that propellant margins would not be adequate to support
the operations.

Officials were asked to investigate the possibility of a rendezvous
with TSS.  After reviewing propellant margins, spacewalking
considerations, and radar requirements, a decision was made not to
fire Columbia's engines to begin what would have been a six-day
phased approach to meet up with the satellite.
  
The Tethered Satellite is currently 7,100 nautical miles ahead of
Columbia with the distance between the two spacecraft closing at the
rate of 340 nm with every revolution of the Earth.  The two spacecraft
will pass within 50 nm of one another about 11:48 p.m.  Thursday, at a
Mission Elapsed Time of 7/09:30.

Earlier today, Mission Specialist Jeff Hoffman set a record for the
most hours flown on a Space Shuttle, breaking the previous record of
975 hours 18 minutes held by Kathy Thornton. Hoffman will break the
1,000 hour mark aboard the Shuttle on Thursday.

Work with the United States Microgravity Payload experiments continues
with the astronauts supporting a variety of investigations including
crystal growth, materials solidification and fluid dynamics.

Columbia is functioning normally, with no problems being tracked by
the flight control team as the Shuttle orbits the Earth every 90
minutes at an altitude of 180 statute miles.

The JSC newsroom will close at 5 p.m. today and will reopen at 6
a.m. Thursday.


    
952.27STS-75 Mission Control Center Status Report # 15ERMTRD::CLIFFEI'll warp my own space-time ...Thu Feb 29 1996 11:5644
STS-75 Mission Control Center Status Report # 15 

Thursday, February 29, 1996, 9 a.m. CST 

Columbia's crew continues its work with the United States Microgravity
Payload experiments supporting a variety of investigations including
crystal growth, materials solidification and fluid
dynamics. Meanwhile, payload controllers continue to obtain snapshots
of data from the tethered satellite as it passes within range of
available groundstations around the world.

As TSS battery power diminishes, plans are in work to turn on science
instruments, Earth sensors and stabilizing gyros in anticipation of
the closest approach of TSS to Columbia at about 11 p.m.  central time
today (approximately 07/08:50 mission elapsed time). At that point,
the orbiter should pass within about 50 miles of the satellite
possibly allowing payload bay instruments a chance to gather data on
the satellite as well.

Because of the instability of the satellite and its varying
gravitational drag, the distance between the two spacecraft and the
time of closest approach likely will change. In any case, there is no
concern about Columbia passing too close to the satellite. Whether or
not the crew can visually observe the satellite during the fly-by will
depend on lighting conditions at that time.

The Tethered Satellite is currently about 3,000 nautical miles ahead
of Columbia with the distance between the two spacecraft closing at
the rate of 340 nm with every revolution of the Earth.

Later today, several of the crewmembers will participate in two
in-flight interviews. The first at 4:20 p.m. is with two Philadelphia
television stations and the second at 6:08 p.m. is with the United
States Information Agency's Worldnet program.

Columbia is functioning normally, with no problems being tracked by
the flight control team as the Shuttle orbits the Earth every 90
minutes at an altitude of 180 statute miles.

The JSC newsroom will close at 5 p.m. today and will reopen at 6
a.m. Friday.


    
952.28STS-75 Mission Control Center Status Report # 16ERMTRD::CLIFFEI'll warp my own space-time ...Mon Mar 04 1996 03:0630
    STS-75 Mission Control Center Status Report # 16
    
    Thursday, February 29, 1996, 5 p.m. CST
    
    Columbia and the Tethered Satellite will pass within about 51 nautical
    miles of each other at 11:17 p.m. central time today (approximately
    7/08:59 MET), providing the astronauts a chance to glimpse the errant
    spacecraft since it separated from the orbiter Sunday night.
    
    Tonight's encounter with TSS marks the point of closest approach
    for the two spacecraft before they begin to separate once again.
    Currently, the orbiter trails TSS by a distance of about 1900 nautical
    miles, with Columbia closing on the satellite at the rate of 340 nm
    with each revolution of the Earth.  Whether or not the crew will be
    able to see the satellite during the fly-by will depend on lighting
    conditions and orbiter position.
    
     This afternoon, crewmembers discussed the progress of the flight
    during an in-flight interview with two Philadelphia television
    stations.  A second interview, at 6:08 p.m., is with the United States
    Information Agency's Worldnet program.
    
    Columbia is functioning normally, with no problems being tracked by
    the flight control team as the Shuttle orbits the Earth every 90
    minutes at an altitude of 180 statute miles.
    
    The JSC newsroom will close at 5 p.m. today and will reopen at 6
    a.m. Friday.
    
    
952.29STS-75 Mission Control Center Status Report # 17ERMTRD::CLIFFEI'll warp my own space-time ...Mon Mar 04 1996 03:0838
    STS-75 Mission Control Center Status Report # 17
    
    Friday, March 1, 1996, 8 a.m. CST
    
    Columbia's astronauts had a clear view of the Tethered Satellite as
    the two spacecraft passed within about 46 nautical miles
    overnight. The closest approach occurred at 11:17 central time last
    night (approximately 7/08:59 MET), and was captured on videotape as
    the satellite and its 12-mile tether came into view.
    
    Meanwhile, flight controllers monitored the Tethered Satellite through
    ground stations as its batteries drained, but not before holding in
    for last night's fly-by.
    
    About 6 a.m. today, weak signals from the satellite, indicating its
    battery life was waning, were observed through the Merritt Island
    tracking station and the Bermuda tracking station.  During a second
    pass across the southern United States about 7:30 a.m. today (7/17:12
    mission elapsed time), ground controllers confirmed there was no
    acquisition of signal from the satellite, effectively ending its
    mission.
    
    Three in-flight special events are planned for the crew this morning
    and early afternoon.  An Italian media interview is set for about 10
    a.m.; an Italian VIP call to crewmembers Maurizio Cheli and Payload
    Specialist Umberto Guidoni is set for 11:50 this morning and a Swiss
    educational event with Mission Specialist Claude Nicollier is
    scheduled for 2:48 this afternoon.
    
    Columbia is continuing to provide a stable platform for microgravity
    investigations as Columbia sails 180 statute miles above the Earth,
    circling the globe every 90 minutes.
    
    The JSC newsroom will close at 5 p.m. today and will reopen at 8
    a.m. Saturday.  Weekend hours are 8 am. to 2 p.m.
    
    
    
952.30STS-75 Mission Control Center Status Report # 18ERMTRD::CLIFFEI'll warp my own space-time ...Mon Mar 04 1996 03:0825
    STS-75 Mission Control Center Status Report # 18
    
    Friday, March 1, 1996, 4 p.m. CST
    
    Science investigations occupied much of the crew's time on board
    Columbia today as the astronauts continued to support the
    U.S. Microgravity Payload.
    
    Experiments into convection and the behavior of flame patterns in
    microgravity were the focus of activity on Columbia's middeck
    today. The astronauts also took time today to share their thoughts
    during an Italian media interview and a Swiss educational event.
    
    Late in the afternoon, Commander Andy Allen, Mission Specialist
    Maurizio Cheli and Payload Specialist Umberto Guidoni accepted a
    congratulatory phone call from Giorgio Salvini, the Italian Minister
    of Universities and Scientific Research.
    
    Columbia continues to perform in near flawless fashion as it sails 180
    statute miles above the Earth, circling the globe every 90 minutes.
    
    The JSC newsroom will close at 5 p.m. today and will reopen at 8
    a.m. Saturday.  Weekend hours are 8 am. to 2 p.m.
    
    
952.31STS-75 Mission Control Center Status Report # 19ERMTRD::CLIFFEI'll warp my own space-time ...Mon Mar 04 1996 03:0929
    STS-75 Mission Control Center Status Report # 19
    
    Saturday, March 2 -- 8 a.m. CST
    
    While science investigations continued on the middeck -- specifically
    studying how fire spreads and soot develops in the microgravity
    environment of space -- a procedure was performed to remove ice from
    the core of Columbia's flash evaporator system which shutdown
    earlier this morning.
    
    The FES core flush procedure was identical to one carried out on the
    last Shuttle flight to melt ice and recover use of the subsystem which
    is designed as a subtle method for dumping excess water overboard
    without disrupting the experiments on board.  The FES also cools the
    freon used to keep orbiter and payload electronics at operating
    temperatures.
    
    Later today, Franklin Chang-Diaz (from Costa Rica) will be interviewed
    by the Spanish NewsChannel and CNN International.  Joining him for the
    4:30 interview are Andy Allen, Jeff Hoffman and Claude Nicollier.
    
    At 7:30 this evening, Jeff Hoffman with other available crew members
    will receive a congratulatory call from organizers of the annual
    Houston Livestock Show and Rodeo.
    
    Columbia's systems continue to operate well, providing a platform for
    USMP operations in orbit 180 miles above the Earth.
    
    
952.32STS-75 Mission Control Center Status Report # 20ERMTRD::CLIFFEI'll warp my own space-time ...Tue Mar 05 1996 03:0327
    STS-75 Mission Control Center Status Report # 20
    
    Sunday, March 3 -- 8 a.m. CST
    
    Flying 180 miles above the Earth, Columbia continues to provide a
    stable platform for the experiments comprising the United States
    Microgravity Payload mission with all orbiter systems performing well.
    
    Science investigations continued through the night without
    interruption. Among the activities, crew members worked with an
    experiment called the Forced Flow Flamespreading Test which studies
    how flames react in the absence of gravity.
    
    This morning, Commander Andy Allen had some time to relax while Pilot
    Scott Horowitz, Mission Specialist Maurizio Cheli, and Payload
    Specialist Umberto Guidoni talked with Voice of America about the
    progress of the flight so far. Later in the day, Horowitz, Cheli and
    Guidoni will have a break from their payload activities while Allen
    continues the scientific investigations.
    
    The Blue Team will wake for its next shift at shortly after 3
    p.m. Central.
    
    Columbia continues to orbit the Earth in smooth fashion at an altitude
    of 180 miles, completing one revolution of the Earth every 90 minutes.
    
    T
952.33STS-75 Mission Control Center Status Report # 21ERMTRD::CLIFFEI'll warp my own space-time ...Tue Mar 05 1996 03:0426
    STS-75 Mission Control Center Status Report # 21
    
    Monday, March 4 -- 8 a.m. CST
    
      Science investigations continue aboard Columbia as mission managers
    on
    the ground contemplate extending the flight at the request of the
    United States Microgravity Payload customer.
    
      Meanwhile, studies into how flame behaves in the absence of gravity
    continue in a controlled environment on the middeck of the orbiter.
    The investigations will hopefully provide additional data for improved
    fire-fighting techniques on Earth.
    
      From an orbiter standpoint, Columbia is in excellent shape supporting
    the USMP operations.  One of the three navigation units on board --
    Inertial Measurement Unit number 3 -- was turned off yesterday after
    controllers monitored small drifts in its gyroscopes.  Drifts such as
    these are compensated through alignments periodically and pose no
    problem for the flight duration since only one IMU is required for on
    orbit operations.  The unit will be turned back on before landing day.
    
      Columbia is in an orbit 182 by 171 statute miles above the Earth
    circling the globe every 90 minutes.
    
    
952.34STS-75 Mission Control Center Status Report # 22ERMTRD::CLIFFEI'll warp my own space-time ...Wed Mar 06 1996 03:0429
    STS-75 Mission Control Center Status Report # 22
    
    Monday, March 4 -- 5 p.m. CST
    
    Columbia's astronauts will spend an additional day in orbit after
    flight controllers opted to extend the flight to support ongoing
    scientific investigations with the United States Microgravity Payload.
    
    Commander Andy Allen responded to the news by telling flight
    controllers the crew was ready to support any additional mission
    extensions. With the additional day, landing is now set for 6:13
    a.m. CST on March 8.
    
    Columbia's astronauts also may have an opportunity to view the
    Tethered Satellite once again as the two spacecraft will pass within
    40-50 nautical miles of each other mid- morning Tuesday.  Flight
    controllers will work through the night to refine the exact time of
    tomorrow's close approach. Currently, Columbia trails the satellite
    at a distance of 3,900 nautical miles, closing the gap at the rate of
    314 nautical miles with every orbit of the Earth.
    
    The seven-member crew will discuss the progress of the mission with
    reporters in the United States and Europe during the traditional
    in-flight news conference at 5:54 central time Tuesday morning.
    
    Columbia continues to provide a stable platform for the USMP science
    activities.
    
    
952.35STS-75 Mission Control Center Status Report # 23ERMTRD::CLIFFEI'll warp my own space-time ...Wed Mar 06 1996 03:0641
    STS-75 Mission Control Center Status Report # 23
    
    Tuesday, March 5 -- 8 a.m. CST
    
    Aboard Columbia, crew members continue to work around the clock
    investigating flame behavior in a controlled, microgravity
    environment.  Early today, a balky cooling system froze up again but
    was cleared using the same procedure run a couple of days ago.
    
    The flash evaporator system core flush procedure was identical to the
    one carried out on Saturday to melt ice and recover use of the
    subsystem which is designed as a subtle method for dumping excess
    water overboard without disrupting the experiments on board.  The FE
    also cools the freon used to keep orbiter and payload electronics at
    operating temperatures.
    
    The unit was turned on to evaluate its operation with freon running at
    a slightly higher temperature than usual to prevent ice formation in
    the core.  The test was conducted on one of two controllers for the
    unit.  A second test on the alternate controller may be conducted
    later.
    
    Columbia is scheduled to pass within 50 to 60 miles of the tethered
    satellite at 10:25 this morning, just as the satellite enters orbital
    sunrise.  It is unclear whether the crew will be able to view the
    satellite as it did several days ago.
    
    This morning, the astronauts took time out from science operations to
    discuss the progress of the mission with reporters in the United
    States and Europe.
    
    With an extra day on orbit for science operations, the seven
    astronauts will continue work supporting the United States
    Microgravity Payload experiments.  The end of Columbia's 19th
    mission is now scheduled for 6:19 a.m. central on Friday.
    
    Despite the intermittent freeze-up of the FES, the orbiter continues
    to provide a stable environment for USMP operations.  Columbia is in
    an orbit 181 by 173 statute miles.
    
    
952.36STS-75 Mission Control Center Status Report # 24ERMTRD::CLIFFEI'll warp my own space-time ...Wed Mar 06 1996 03:0732
    STS-75 Mission Control Center Status Report # 24
    
    Tuesday, March 5 -- 4 p.m. CST
    
    Columbia's astronauts had one last look at the Tethered Satellite
    late this morning telling flight controllers they could see both the
    satellite and the tether hanging beneath it.
    
    Lighting precluded a viewing opportunity during the point of closest
    approach between the two spacecraft, but one orbit later the crew saw
    and filmed TSS from a distance of about 450 nautical miles.  The
    videotape was played back for flight controllers on the ground this
    afternoon.  Today's pass of the satellite marks the final viewing
    opportunity for the seven astronauts on board Columbia.
    
    Shortly before 7 p.m. central today, Franklin Chang-Diaz, Jeff Hoffman
    and Claude Nicollier will participate in the final on-orbit interview
    for the flight.  The three crew members will discuss their missions
    with both Univision and Telenoticias, the two largest Hispanic
    television networks.
    
    Wednesday morning, Commander Andy Allen will attempt to make contact
    with the crew of Atlantis on Launch Pad 39-B. STS-76 Commander Kevin
    Chilton and the crew of the next Shuttle/Mir mission will be on board
    Atlantis participating in a final dress rehearsal of their planned
    March 21 launch.
    
    Columbia continues to provide a stable platform for the continuing
    scientific investigations being conducted in the United States
    Microgravity Payload.
    
    
952.37STS-75 Mission Control Center Status Report # 25ERMTRD::CLIFFEI'll warp my own space-time ...Thu Mar 07 1996 03:0937
    STS-75 Mission Control Center Status Report # 25
    
    Wednesday, March 6 -- 8 a.m. CST
    
    Columbia flew over the Shuttle launch site this morning allowing
    STS-75 Commander Andy Allen and STS-76 Commander Kevin Chilton the
    opportunity to talk briefly while the Atlantis crew practiced its
    launch countdown at the Kennedy Space Center.
    
    STS-76 remains scheduled for launch in the early hours of March 21 to
    begin the third docking mission of a Shuttle to the Russian Space
    Station Mir.  The mission commanders exchanged greetings as the STS-75
    crew crowded around Columbia's overhead windows to catch a glimpse
    of KSC as they passed overhead.
    
    Meanwhile, with an extension day ahead of them, Columbia's seven
    astronauts continue around the clock operation and oversight of the
    various microgravity investigations that make up this third mission of
    the United States Microgravity Payload.
    
    Small thruster firings to put Columbia into a subtle 360-degree
    rotation were conducted to allow experimenters the opportunity to
    gather data into how movements such as these affect samples being
    grown in the quiet, stable environment of space.
    
    Mission managers are evaluating the long-range weather forecast for
    Friday -- the scheduled day for landing -- to determine if it will be
    acceptable for landing.  The current landing time is 6:19 a.m. central
    on the first of three available opportunities that day.  Columbia has
    enough consumables on board to stay in space into the early part of
    next week.
    
    Columbia continues to provide a stable platform for the continuing
    scientific investigations being conducted in the United States
    Microgravity Payload.
    
    
952.38STS-75 Mission Control Center Status Report # 26ERMTRD::CLIFFEI'll warp my own space-time ...Fri Mar 08 1996 03:0737
    STS-75 Mission Control Center Status Report # 26
    
    Wednesday, March 6 -- 4 p.m. CST
    
    After 13 days in orbit, Columbia's astronauts are preparing for
    their return trip to Earth.
    
    Tonight, the crew will deactivate and stow the Middeck Glove Box
    experiment, used during the flight to study the behavior of flame in a
    microgravity environment. A special low-light camera in Columbia's
    payload bay, called TOP, will make some final observations of the
    luminous glow that surrounds the shuttle as its surfaces react to
    atomic oxygen.
    
    Early Thursday morning, Commander Andy Allen, Pilot Scott Horowitz and
    Mission Specialist Maurizio Cheli will perform the standard checks of
    Columbia's flight control surfaces and reaction control system to
    prepare the orbiter for reentry and landing.  Allen and Horowitz also
    will fine tune their landing skills using a portable laptop computer
    called PILOT which simulates the orbiter's reentry and landing
    profile.
    
    There are three opportunities for Columbia's return to the Kennedy
    Space Center on Friday morning.  The targeted landing time is 6:19
    a.m. central, with back-up opportunities at 7:55 a.m. and 9:31 a.m.
    Mission managers are evaluating the long-range weather forecast for
    Friday to determine if it will be acceptable for landing at KSC.
    Current predictions call for low, broken and scattered clouds, and a
    chance of rain and gusty winds. The alternate landing site at Edwards
    Air Force Base in California, will not be called up to support a
    Friday landing, but weather conditions at Edwards are expected to be
    acceptable throughout the weekend.
    
    Columbia continues to perform well as its 19th journey in space nears
    its end.
    
    
952.39STS-75 Mission Control Center Status Report # 28ERMTRD::CLIFFEI'll warp my own space-time ...Fri Mar 08 1996 03:0945
    STS-75 Mission Control Center Status Report # 28
    
    Thursday, March 7 -- 4 p.m. CST
    
    Columbia's astronauts have readied their ship to return to Earth after
    a journey of more than 6 million miles.  Landing at the Kennedy Space
    Center is targeted for 7:52 a.m.  central time, the first of two
    opportunities to KSC tomorrow.
    
    Early this morning, during the standard pre-landing check of
    Columbia's flight control system, one of four data channels
    failed. The command path involved is one of four that commands an
    actuator to move flight control surfaces during reentry.  The command
    path is considered "failed", but the three remaining command
    paths remain healthy and in position to support tomorrow's planned
    landing.
    
    Throughout the night, the reentry flight control team will continue to
    review weather conditions at the primary landing site at KSC, as well
    as the alternate landing site at Edwards Air Force Base in California.
    
    Flight controllers opted to forego an earlier KSC landing opportunity
    at 6:16 a.m. central time, because of forecast low clouds and the
    possibility of rain and gusty winds.  Weather conditions are expected
    to improve later in the morning to support the two KSC landing
    opportunities.
    
    The first landing opportunity would see a deorbit firing of
    Columbia's engines at 6:49 a.m.  central time, with a landing on
    Runway 33 at 7:52 a.m.  The second opportunity, one orbit later, has a
    deorbit burn at 8:25 a.m., followed by landing at 9:27 a.m.
    
    If weather precludes a landing at KSC, there are two opportunities for
    a Friday landing at Edwards Air Force Base.  The first would see a
    deorbit burn of Columbia's engines at 8:15 a.m. central time, with
    landing on Runway 22 at 9:27 a.m.  The second opportunity, has a
    deorbit burn at 9:54 a.m. central time with landing at 10:54 a.m.
    Weather in California is predicted to be acceptable to support
    landing.
    
    If Columbia remains in orbit an additional day due to weather
    conditions, there are three landing opportunities available on
    Saturday at KSC and three at Edwards.
    
    
952.40It's down.ERMTRD::CLIFFEI'll warp my own space-time ...Mon Mar 11 1996 03:3125
    Flight Day 17
    
    Space Shuttle Columbia completed a 16-day science mission this morning
    with a landing at 7:58 a.m. CST at the Kennedy Space Center in Florida.
    An early landing opportunity this morning was passed over because of
    cloudy conditions at the landing site, but weather conditions improved
    for the one-orbit later end of mission. 
    
    The seven-member flight crew will return to Houston to a welcoming
    ceremony at Ellington Field Saturday mid-afternoon at the Hangar 990
    area. The event is open to the public. This recording will be updated
    later today as the crew return time becomes known. 
    
    Columbias flight covered approximately six and a half million miles in
    251 orbits of the Earth. It was the 75th mission of the Shuttle program
    and Columbias 19th trip into space. Originally scheduled to end
    Thursday, the flight was first extended one day to gain additional
    science time on orbit and extended until Saturday after landing
    opportunities Friday were missed due to unacceptable weather in
    Florida. 
    
    Columbias entry ground track took it across Mexico, the center of Texas
    and Louisiana before tracking over the Gulf of Mexico on its way to the
    Florida landing site. The orbiters main gear touched the runway at 7:58
    a.m. and 21 seconds.
952.41STS-75 Mission Control Center Status Report # 29ERMTRD::CLIFFEI'll warp my own space-time ...Tue Mar 12 1996 08:0231
    STS-75 Mission Control Center Status Report # 29
    
    Friday, February 8, 1996, 9 a.m.
    
    Shuttle managers today elected to wait for better weather in Florida
    on Saturday due to unpredictable cloud cover this morning at Kennedy
    Space Center.  The weather forecast indicates improved conditions
    Saturday.
    
    Today's landing opportunities slipped by one by one as the flight
    control team saw some improvement in cloud cover at the KSC landing
    site, only to be faced with a prediction of bands of low clouds moving
    over the runway area at the scheduled landing time.  Weather was
    generally good at Edwards Air Force Base, the alternate site, but with
    some hope of better weather in Florida Saturday, managers decided to
    keep Columbia in orbit one additional day.
    
    Early Friday, Columbia's astronauts prepared the vehicle for entry,
    packing up gear aboard the shuttle and closing the payload bay doors.
    They will now reopen the doors to provide necessary cooling and go
    through the deorbit preparations again Saturday morning.
    
    The first opportunity Saturday for a KSC landing comes on orbit 250
    with a deorbit burn at 5:23 a.m. CST and a landing at 6:24 a.m. CST.
    The second KSC opportunity is at 7:59 a.m. CST and the final
    opportunity in Florida comes at 9:35 a.m.
    
    Edwards landing opportunities Saturday morning are at 7:51, 9:26 and
    11:01 CST.
    
    
952.42STS-75 Mission Control Center Status Report # 30ERMTRD::CLIFFEI'll warp my own space-time ...Tue Mar 12 1996 08:0324
    STS-75 Mission Control Center Status Report # 30
    
    Friday, February 8, 1996, 5 p.m.
    
    Space Shuttle Columbia's astronauts were scheduled to awaken about
    10:30 p.m. Friday night to begin preparations for a Saturday landing,
    concluding over two weeks of science operations in space.  Shuttle
    managers earlier today elected to pass up landing at the Edwards Air
    Force Base in California Friday in the hope that improving weather at
    Kennedy Space Center in Florida would allow for a landing there
    Saturday.
    
    Early Saturday, Columbia's astronauts will prepare the vehicle for
    entry, packing up gear aboard the shuttle, closing the payload bay
    doors and getting into their launch/entry suits.
    
    The first opportunity Saturday for a KSC landing comes on orbit 250
    with a deorbit burn at 5:23 a.m. CST and a landing at 6:24 a.m. CST.
    The second KSC opportunity is at 7:59 a.m. CST and the final
    opportunity in Florida comes at 9:35 a.m.
    
    Edwards landing opportunities Saturday morning are at 9:26 and 11:01
    CST.
    
952.43STS-75 Mission Control Status Report #31ERMTRD::CLIFFEI'll warp my own space-time ...Tue Mar 12 1996 08:0429
    STS-75 Mission Control Status Report #31
    
    Saturday, March 9  8:30 a.m.
    
    
    Space Shuttle Columbia completed a 16-day science mission this morning
    with a landing at 7:58 a.m. CST at the Kennedy Space Center in
    Florida.  An early landing opportunity this morning was passed over
    because of cloudy conditions at the landing site, but weather
    conditions improved for the one-orbit later end of mission.
    
    The seven-member flight crew will return to Houston to a welcoming
    ceremony at Ellington Field Saturday mid-afternoon at the Hangar 990
    area.  The event is open to the public.  This recording will be
    updated later today as the crew return time becomes known.
    
    Columbia's flight covered approximately six and a half million
    miles in 251 orbits of the Earth.  It was the 75th mission of the
    Shuttle program and Columbia's 19th trip into space.  Originally
    scheduled to end Thursday, the flight was first extended one day to
    gain additional science time on orbit and extended until Saturday
    after landing opportunities Friday were missed due to unacceptable
    weather in Florida.
    
    Columbia's entry ground track took it across Mexico, the center of
    Texas and Louisiana before tracking over the Gulf of Mexico on its way
    to the Florida landing site.  The orbiters main gear touched the
    runway at 7:58 a.m. and 21 seconds.
    
952.44AUSSIE::GARSONachtentachtig kacheltjesTue Mar 12 1996 20:137
    re .42
    
>    STS-75 Mission Control Center Status Report # 30
>    
>    Friday, February 8, 1996, 5 p.m.
    
    Gee, that must make it the longest shuttle mission on record.
952.45TSS Tether failure analysis report releasedNETCAD::BATTERSBYDon't use time/words carelesslyWed Jun 05 1996 10:01155
Michael Braukus
Headquarters, Washington, DC                    June 4, 1996
(Phone:  202/358-1979)

Jerry Berg
Marshall Space Flight Center, Huntsville, AL
(Phone:  205/544-0034)

Enzo Letico
ASI, Washington, DC
(Phone: 202/863-1298)

RELEASE:  96-112

TETHERED SATELLITE INVESTIGATION REPORT IS RELEASED

    NASA and the Italian Space Agency (ASI) today released the 
report of the investigative board appointed to determine 
factors which resulted in the Feb. 25 tether break and loss of 
the Tethered Satellite during the STS-75 Space Shuttle mission.

    Findings of the board, included in a 358-page document, 
identified primary causes which accounted for the tether break 
during deployment of the Tethered Satellite.

    "The tether failed as a result of arcing and burning of 
the tether, leading to a tensile failure after a significant 
portion of the tether had burned away," the report concludes.  
The arcing occurred because either external foreign object 
penetration (but not orbital debris or micrometeoroids) or a 
defect in the tether caused a breach in the layer of 
insulation surrounding the tether conductor.  The insulation 
breach provided a path for the current to jump, or arc, from 
the copper wire in the tether to a nearby electrical ground.

    The board found that the arcing burned away most of the 
tether material at that location, leading to separation of the 
tether from tensile or pulling force.  The break occurred when 
approximately 12.2 miles (19.7 km) of tether was unreeled, in 
a period when the tether was experiencing normal stresses of 
approximately 15 pounds (65 newtons).

    In addition to the two primary causes for the tether 
break, the board cited, as one contributing factor, that "the 
degree of vulnerability of the tether insulation to damage was 
not fully appreciated."  The board noted that the actual 
environment that the tether was exposed to in flight made it 
more vulnerable to damage than was expected.  And, it noted 
that the high voltages under which the system was operating 
could, over a period of time, have reduced the ability of the 
tether insulation to withstand electrical breakdown due to 
contamination found in the tether.

     "The tether itself was a remarkable engineering 
achievement," said Ken Szalai, who chaired the investigative 
board, "and produced some startling scientific discoveries." 
Scientific papers recently presented at an American 
Geophysical Union conference reported that currents generated 
by the tether were three times higher than theoretical models 
had predicted prior to the flight.

     "Constructing a tether that was strong, lightweight and 
electrically conducting took the project into technical and 
engineering areas where they had never been before," said 
Szalai. "Now, with 20/20 hindsight, they know where the system 
is vulnerable and can improve the design."

    The Tethered Satellite System is a joint NASA-ASI system 
that was flown aboard Space Shuttle Columbia in an experiment 
to better understand the electrically charged environment of 
Earth's ionosphere, and how tether systems behave in it.  ASI 
had the responsibility of providing the satellite, while NASA 
had the responsibility of the Deployer, which includes the 
tether, and the overall responsibility for payload integration 
and operations.  The provision of science investigations was 
shared by ASI and NASA.

    The system was generating 3,500 volts DC and up to 0.5 
amps of current during satellite deployment.  That high level 
of electrical energy resulted from the length of conducting 
tether extending from the Shuttle, coupled with the 17,500-
mile-per-hour speed at which the Shuttle and tether were 
cutting through Earth's magnetic field lines.

    The board found sufficient evidence to identify two 
possible causes of the breach in the insulation -- foreign 
object damage, or a defect in the tether itself.  Debris and 
contamination found in the deployer mechanisms and in the 
tether itself could have been pushed into the insulation layer 
while the tether was still wound on its reel.  The 
investigation found evidence of damage to copper wire in the 
tether, and also established that normal forces on the tether 
while on the reel could push a single copper strand or foreign 
debris through the insulation.

    The arcing, which began in an intricate part of the 
Tethered Satellite System known as the lower tether control 
mechanism, sputtered intermittently for nine seconds as the 
moving tether passed through deployer mechanisms and then into 
the boom area of the tether system.  At the time, tether was 
continuing to play out at one meter per second, or slightly 
more than three feet per second.

    "This arcing produced significant burning of most of the 
tether material in the area of the arc," the board found.  The 
tether was designed to carry up to 15,000 volts DC and handle 
tensile forces of up to 400 pounds (1780 newtons). It used 
super-strong strands of Kevlar as a strength-providing member, 
wound around the copper and insulation.  However, postflight 
inspection of the tether end which remained aboard Columbia 
showed it to be charred.  The board concluded that after 
arcing had burned through most of the Kevlar, the few 
remaining strands were not enough to withstand forces being 
exerted by satellite deployment.

    Extensive, rigorous tests performed in support of the 
investigation established that undamaged tether would not arc, 
even when subjected to electrical potentials much higher than 
the 3500 volts experienced during the mission.

    The board was able to exonerate a number of factors which 
clearly did not cause the break.  These factors include the 
satellite, the science equipment hardware and operations, 
which were being conducted prior to the break, in addition to 
micrometeoroids or orbital debris impact, and electrical storm 
activity.

    The investigation panel made several detailed 
recommendations which it said should be followed for any 
future space missions involving electrodynamic tether systems 
such as that flown aboard Columbia.  These include more 
precautions to ensure any such tether systems in the future do 
not suffer from possible debris or contamination damage and 
specific attention during design to minimize the possibility 
of high-voltage arcing.

    The board offered, in the form of observations, its 
assessment that the STS-75 tether problem "is not indicative 
of any fundamental problem in using electrodynamic tethers."  
It also noted that in spite of the break, a "significant 
amount" of scientific data was obtained from the Tethered 
Satellite operations during STS-75.

    The nine-member independent review panel was formed in 
consultation with ASI and appointed by NASA's Associate 
Administrator for the Office of Space Flight, Wilbur Trafton, 
shortly after the tether break.  The board was chaired by Ken 
Szalai, director of the Dryden Flight Research Center, 
Edwards, CA, and included representation from NASA and the ASI.

                          -end-

--