Conference 7.286::space

    Any plans beyond the next encounter :-)

Article: 945
From: [email protected] (Ron Baalke)
Newsgroups: sci.space.news
Subject: Giotto Update - 05/07/92
Date: 8 May 92 00:36:56 GMT
Sender: [email protected] (Usenet)
Organization: Jet Propulsion Laboratory
 
 
                              GIOTTO STATUS REPORT
                                  May 7, 1992
 
   Giotto reactivation activities continue.  Yesterday's objectives
with Goldstone's 70 meter antenna were successfully met.  Telemetry
downlink was received via the Low Gain Antenna with acquisition on
time.  A lengthy Earth-aspect angle maneuver was successfully
completed and the downlink was switch to the High Gain Antenna (HGA). 
HGA pointing refinement maneuvers were performed and may continue with
the 70 meter Madrid antenna today.  Coded telemetry at 360 bps was
turned on at 02:23 (UTC). 

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Denial is always the first
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | symptom.
|_____|/  |_|/       |_____|/                     | 

Article: 24159
Newsgroups: sci.space,sci.astro
From: [email protected] (Ron Baalke)
Subject: Re: Space Calendar - 06/29/92
Sender: [email protected] (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 30 Jun 1992 23:38:20 GMT
 
In article <[email protected]>, [email protected]
(Nick Szabo) writes... 

>In article <[email protected]>
>[email protected] writes: 
> 
>>1992
>>   July
>>     10 - Giotto, Comet Grigg-Skjellerup Flyby
>>     22 - Comet Grigg-Skjellerup Perihelion
> 
>Good luck to the Giotto crew!  Let us know how it goes!
 
A quick update.  Giotto will be traveling at 50,000 km/h when it
reaches the comet.  It is targeted directly for the comet, but there
is a million to 1 chance of actually colliding with the comet and will
instead pass within 1000 km.  Seven of Giotto's instruments are operational 
(though not the camera) and they will measure the magnetic field and the 
density and composition of the dust and gas around the comet. 

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | Pound for pound,
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | grasshoppers are 3 times as
|_____|/  |_|/       |_____|/                     | nutritious as beef.
 

Article: 24340
Newsgroups: sci.space,sci.astro
From: [email protected] (Anita Cochran)
Subject: Re: RA and Dec. of Grigg-Skjellerup?
Organization: Univ. of Texas McDonald Observatory
Date: Mon, 6 Jul 1992 19:30:11 GMT
 
In article <[email protected]>, [email protected] (H.Yano) writes:

> 	Could anyone please post the right ascension and declination of
> Comet Grigg-Skjellerup during the Giotto Extended Mission encounter at
> the end of this week?
 
Here is an ephemeris for Grigg-Skjellerup (from the International Comet
Quarterly 1992 Comet Handbook, Nakano and Green eds):
 
Date        RA  (1950)  Decl     Delta    R    Magnitude  Elong
June 27   09 17.43   +07 42.8    1.494  1.055  14.1/19.3   44.9
Jul 7     09 57.89   +07 09.7    1.445  1.017  13.5/19.2   44.8
Jul 17    10 40.89   +06 19.9    1.402  0.997  13.2/19.1   45.3
 
In this ephemeris, Delta is the geocentric distance, R the
heliocentric distance, the elong is the solar elongation angle and the
two magitudes are the total and nuclear magnitudes, respectively.  As
you can see it is reasonably near the sun, making observations a
little difficult. 
 
A quadratic interpolation should be good enough for intermediate
positions, but if anyone wants to calculate daily or hourly positions,
the elements are: 

   T    1992 July 22.1380
   q    0.994689
   e    0.664325                        Equinox 1992 Aug 6.0
   Peri 359.2761                        Epoch B1950.0
   Node 212.6315
   i    21.1042
-- 
 Anita Cochran  uucp:  !utastro!anita
                arpa:  [email protected]  
                snail: Astronomy Dept., The Univ. of Texas, Austin, TX, 78712
                at&t:  (512) 471-1471

Article: 24348
From: [email protected] (Dave Tholen)
Newsgroups: sci.space,sci.astro
Subject: Re: RA and Dec. of Grigg-Skjellerup?
Date: 7 Jul 92 00:21:51 GMT
Sender: [email protected] (News Service)
Organization: Institute for Astronomy, Hawaii
 
In article <[email protected]> [email protected] (H.Yano) writes:
 
>	Could anyone please post the right ascension and declination of
> Comet Grigg-Skjellerup during the Giotto Extended Mission encounter at
> the end of this week?
 
P/Grigg-Skjellerup           1986m 
 
                     R.A. (B1950.00) DEC.    V     DISTANCE  SOLAR LUNAR LUNAR
  UT DATE / TIME   HR MN  SEC  DEG AM ASEC  MAG   SUN  EARTH ELONG ELONG PHASE
 
1992 Jul 07 00:00  09 57 52.44 +07 09 42.4 19.86 1.017 1.445  44.7  43.8 0.489
1992 Jul 08 00:00  10 02 04.03 +07 05 27.8 19.85 1.014 1.440  44.8  56.4 0.598
1992 Jul 09 00:00  10 06 17.13 +07 01 03.1 19.84 1.012 1.436  44.8  68.6 0.700
1992 Jul 10 00:00  10 10 31.70 +06 56 28.6 19.84 1.009 1.431  44.8  80.6 0.791
1992 Jul 11 00:00  10 14 47.70 +06 51 44.1 19.83 1.007 1.427  44.9  92.3 0.867
1992 Jul 12 00:00  10 19 05.12 +06 46 49.8 19.82 1.005 1.422  44.9 103.8 0.928
1992 Jul 13 00:00  10 23 23.92 +06 41 45.7 19.82 1.003 1.418  45.0 115.1 0.970
1992 Jul 14 00:00  10 27 44.07 +06 36 31.9 19.81 1.001 1.414  45.1 126.2 0.994
1992 Jul 15 00:00  10 32 05.52 +06 31 08.4 19.81 1.000 1.410  45.1 137.2 0.999
1992 Jul 16 00:00  10 36 28.26 +06 25 35.2 19.80 0.998 1.406  45.2 148.0 0.986
1992 Jul 17 00:00  10 40 52.24 +06 19 52.5 19.80 0.997 1.402  45.3 158.8 0.956
1992 Jul 18 00:00  10 45 17.42 +06 14 00.3 19.79 0.996 1.399  45.4 169.2 0.909
1992 Jul 19 00:00  10 49 43.77 +06 07 58.6 19.79 0.996 1.395  45.5 176.2 0.847
1992 Jul 20 00:00  10 54 11.24 +06 01 47.6 19.79 0.995 1.392  45.6 167.9 0.773
1992 Jul 21 00:00  10 58 39.81 +05 55 27.3 19.78 0.995 1.388  45.7 157.3 0.688
 
Epoch:  1992 Jun 27
Site:   Geocenter                                          

Article: 24480
Newsgroups: sci.space,sci.astro
From: [email protected] (Henry Spencer)
Subject: Re: GIOTTO and GRIGG-SKJELLERUP (on TV!)
Date: Fri, 10 Jul 1992 16:29:22 GMT
Organization: U of Toronto Zoology
 
In article <[email protected]>
[email protected] (Patrick S. Golden) writes: 

>I heard on "Stardate" this morning that the camera on Giotto
>was damaged during its Halley encounter...
 
Written off, in fact.  Unless there has been some sudden development,
the camera's outer baffle and mirror are believed to have been smashed
during the Halley encounter.  All attempts to get an image out of the
camera have been unsuccessful, and the baffle is not casting a shadow
on the adjacent solar array like it should.  The G-S encounter is
mostly a fields-and-particles operation. 
-- 
There is nothing wrong with making      | Henry Spencer @ U of Toronto Zoology
mistakes, but... make *new* ones. -D.Sim|  [email protected]  utzoo!henry

Article: 24483
Newsgroups: sci.space,sci.astro
From: [email protected] (Ron Baalke)
Subject: Re: GIOTTO and GRIGG-SKJELLERUP (on TV!)
Sender: [email protected] (Usenet)
Organization: Jet Propulsion Laboratory
Date: Sat, 11 Jul 1992 00:57:14 GMT
 
In article <[email protected]>, [email protected] (Henry
Spencer) writes... 

>In article <[email protected]>
>[email protected] (Patrick S. Golden) writes: 
>>I heard on "Stardate" this morning that the camera on Giotto
>>was damaged during its Halley encounter...
> 
>Written off, in fact.  Unless there has been some sudden development,
>the camera's outer baffle and mirror are believed to have been smashed
>during the Halley encounter.  All attempts to get an image out of the
>camera have been unsuccessful, and the baffle is not casting a shadow
>on the adjacent solar array like it should.  The G-S encounter is
>mostly a fields-and-particles operation.
 
The telmetry returned from Giotto has shown that the camera is still
funtioning but is is not usuable because something is blocking the
camera's view.   The most likely explanation is that stray light
baffle suffered damage during the Halley flyby and was pushed into the
camera's line of sight.  Attempts will be made to see if the camera
can be used for the Grigg-Skjellerup flyby, but it is very unlikely
that this will be successful. 

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | In 1991 there were 16 names
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | listed on the FBI's ten
|_____|/  |_|/       |_____|/                     | most wanted list.
 
Article: 24489
Newsgroups: sci.space,sci.astro
From: [email protected] (Henry Spencer)
Subject: Re: GIOTTO and GRIGG-SKJELLERUP (on TV!)
Date: Fri, 10 Jul 1992 18:08:30 GMT
Organization: U of Toronto Zoology
 
In article <[email protected]>
[email protected] writes: 

>>... All attempts to get an image out of the
>>camera have been unsuccessful...
>
>The telmetry returned from Giotto has shown that the camera is still
>funtioning but is is not usuable because something is blocking the
>camera's view...
 
Correct; I should have been clearer in my original wording.  The
problem is not that the camera isn't giving images, but that it isn't
giving useful images -- they're blank. 
-- 
There is nothing wrong with making      | Henry Spencer @ U of Toronto Zoology
mistakes, but... make *new* ones. -D.Sim|  [email protected]  utzoo!henry

Article: 24565
Newsgroups: sci.space,sci.astro
From: [email protected] (Ron Baalke)
Subject: Giotto Update - 07/13/92
Sender: [email protected] (Usenet)
Organization: Jet Propulsion Laboratory
Date: Tue, 14 Jul 1992 00:30:46 GMT
 
                             GIOTTO STATUS REPORT
                                July 13, 1992
 
     On July 10 the Giotto spacecraft encounterd Comet Grigg-Skjellerup 
with the closest approach to the nucleus at about 200 km.  The flyby went 
extremely well as the spacecraft gathered data on the comet with seven of 
its instruments.  Encounter operations with Comet Grigg-Skjellerup using 
NASA's Deep Space Network were encountered with no uplink to the spacecraft.  
The spacecraft configuration was adjusted for a non-coherent mode should 
an uplink be required.  Visual indications of the encounter consisted of 
a sharp negative change of approximately 120 Hz in the doppler residuals 
and a small decrease in the downlink AGC (Automatic Gain Control). Tracking
passes of the spacecraft with the 70 meter antennas in Madrid and Canberra 
continued through July 12. 

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | In 1991 there were 16 names
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | listed on the FBI's ten
|_____|/  |_|/       |_____|/                     | most wanted list.
 

Article: 24559
From: [email protected] (Paul Leyland)
Newsgroups: sci.space,sci.astro
Subject: Re: GIOTTO and GRIGG-SKJELLERUP (on TV!)
Date: 13 Jul 92 12:41:02 GMT
Sender: [email protected]
Organization: Oxford University Computing Service, 13 Banbury Rd, Oxford, OX2
 
In article <[email protected]> [email protected]
(George William Herbert) writes: 
 
	   One of our ISU students, Ralph Lorenz, is on the Giotto team
   and has been saying for the last week that he's sure Giotto will die
   during the encounter from a dust collision.  Anyone know if it did or not?
 
Yes it did.  SFAIK, it will burn most of the remaining fuel to put it
into an Earth-intercepting orbit for a 1999 flyby.  Apparently there
are several accessible comets being thought about.  Of course, it's
just about possible that a new major comet might turn up on cue. 
 
Giotto must be one of the great successes of the space era.  Not to
take anything away from Voyager, Viking et. al, but surviving two
close encounters with comets and capable of a third is pretty good
going for a robot not expected to survive even the first. 
 
Paul
--
Paul Leyland <[email protected]>          | Hanging on in quiet desperation is
Oxford University Computing Service      |     the English way.
13 Banbury Road, Oxford, OX2 6NN, UK     | The time is come, the song is over.
Tel: +44-865-273200  Fax: +44-865-273275 | Thought I'd something more to say.

Article: 24560
From: [email protected] (Paul Leyland)
Newsgroups: sci.space,sci.astro
Subject: Re: GIOTTO and GRIGG-SKJELLERUP (on TV!)
Date: 13 Jul 92 12:35:55 GMT
Sender: [email protected]
Organization: Oxford University Computing Service, 13 Banbury Rd, Oxford, OX2
 
In article <[email protected]>
[email protected] (Patrick S. Golden) writes: 
 
   I heard on "Stardate" this morning that the camera on Giotto
   was damaged during its Halley encounter.  If this is the case,
   wouldn't this program just be a general informational one
   without any "live" pictures?
 
   (Not that I can get the BBC anyway, but it's good info in any
 
It was boadcast during working hours and I forgot to tape it 8-(
 
I saw a few snippets.  No live pictures, but several live data feeds.
E.g we heard about significant dust impacts, e-m field changes etc
from the link to the groundstation.  Several tame experts
pontificating for the public's benefit. 
 
Nice of the BBC to drop regular scheduling to give us live action from
a blind, seriously battered and elderly spacecraft visiting an obscure
comet.  Almost makes the license fee worth paying. 8-) 
 
[In case furriners didn't realise, Britons have to pay a substantial
sum annually, about $150 in US terms, for the privilege of receiving
*any* broadcast TV signal, not just the BBC.  Oh, slight inaccuracy.
That's for colour receivers; monochrome only is a lot cheaper and only
one license per household is needed, subject the typical bureaucrats
cop-outs...] 
 
Paul
--
Paul Leyland <[email protected]>          | Hanging on in quiet desperation is
Oxford University Computing Service      |     the English way.
13 Banbury Road, Oxford, OX2 6NN, UK     | The time is come, the song is over.
Tel: +44-865-273200  Fax: +44-865-273275 | Thought I'd something more to say.

Article: 45961
Newsgroups: sci.space
From: [email protected] (Anthony Frost)
Subject: Re: GIOTTO and GRIGG-SKJELLERUP (on TV!)
Date: Sun, 12 Jul 1992 16:05:00 +0000
Sender: [email protected]
 
  > I heard on "Stardate" this morning that the camera on Giotto
  > was damaged during its Halley encounter.  If this is the
  > case, wouldn't this program just be a general informational
  > one without any "live" pictures? 
 
I watched this programme (there *are* advantages to being out of
work!) yesterday afternoon, and it was done very well. No pictures due
to something obscuring the camera, but the various instrument groups
were doing a very good job of explaining what they were expecting, and
how the incoming data differed from that predicted, at regular intervals. 
 
         Anthony
 
BTW, in a quick interview with the head of NASA who was visiting for
the encounter, he managed to avoid saying anything about joining the
"Rossetta" comet sample and return mission when asked! 

 
    "I believe that there are moments in history when challenges occur of
  such a compelling nature that to miss them is to miss the whole meaning 
  of an epoch.  Space is such a challenge." - James A. Michener 
 
    "In the middle of the night we were lying on the ceiling looking
  out the window at the most fantastic thing that any human being has
  ever seen.  Then we both said it almost at the same time - that the
  only sadness to the whole experience was the fact that there was the
  very real possibility that our wives and children would never share
  that with us." - Robert Cenker

    I also watched the show & a rushed afair it was too.
    
    It appears that Gitto made its closest approach about 1.5 mins after
    the planned approach.  Its collison detectors only detected 4 hits,
    this may have been due to its angle of approach, Halley was direct.
    
    This comet held a couple of surprises the bow shock was much larger
    than expected and the dead zone near the nucelus was not detected.
    
    Chris

Article: 25309
Newsgroups: sci.space,sci.astro
From: [email protected] (Ron Baalke)
Subject: Giotto - First Results from Comet Encounter
Sender: [email protected] (Usenet)
Organization: Jet Propulsion Laboratory
Date: Thu, 6 Aug 1992 05:18:01 GMT
 
ESA News Release
 
The Giotto Extended Mission
First Results from the Encounter with Comet Grigg-Skjellerup
 
     On 10 July 1992, at 15h30 UTC, the Giotto spacecraft passed
within approximately 200 km of the nucleus of comet Grigg-Skjellerup. 
The payload had been switched-on in the evening of 9 July - then the
uplink was removed to provide the maximum onboard power margin for a
safe operation fo the payload.  Eight out of the original complement
of eleven experiments were operated and provided a surprising wealth
of exciting data: Magnetometer, Johnstone Plasma Analyser, Energetic
Particle Analyser, Optical Probe Experiment, Reme Plasma Analyser,
Dust Impact Detection System, Ions Mass Spectrometer and Giotto
Radioscience Experiment. 
 
     Already at about 600,000 km from the nucleus, i.e. 12 hours
before the closest approach, the Johnstone Plasma Analyser (JPA)
detected the first presence of cometary ions.  At a distance of
18-15,000 km both JPA and the Reme Plasma Analyser (RPA) reported what
looked like a bow shock or a bow wave, much more distinct than had
been predicted for such a weak comet.  The Magnetometer measurements
carried out during the inbound trajectory could not confirm this
finding, but reported exciting wave phenomena not seen in a natural
plasma before.  However, on the outbound trajectory the Magnetometer
saw clear indications of a shock. 
 
     The Optical Probe Experiment got the first indication of entering
the dust coma at around 20,000 km and from their data could derive the
first estimate for the encounter distance of approximately 200 km. 
Together with Magnetometer data there is good evidence that Giotto
passed the nucleus on the "dark" side, i.e. in the tail forming region. 
 
     At 15:30:56 the Dust Impact Detectors reported the first impact
of a fairly large particle, followed by two smaller ones. 
 
     At 15:31:02, shortly after the first impact, the High Gain
Antenna appeared to be oscillating slightly around its nominal value. 
An increase of the spin rate by 0.003 RPM was also observed while the
Solar Aspect Angle readings were fluctuating between 89.26 and 89.45
degrees, pointing out a nutation of about 0.1 degrees.  This was also
recorded by the Radioscience Experiment and is awaiting further evaluation. 
 
     The Energetic Particle Experiment saw clear indications of the
acceleration regions and surprising differences in the structures
between the Halley encounter and Grigg-Skjellerup.  Last but not
least, the Ion Mass Spectrometer recorded good data, however the data
analysis for this instrument is quite cumbersome and complex, on the
account fo the low encounter velocity (14 km as compared with 68 km/s'
at Halley). 
 
     A thorough test of the camera on-board Giotto on 7 July 1992
could only confirm that the optical path was very effectively blocked.
 However, on 12 July a number of tests were performed with the
detectors of the Halley Multicolour Camera, which had provided very
valuable engineering and calibration data on the long term behaviour
of the CCDs in space. 
 
     All experimenters were - and still are - enthusiastic about the
quality of the data returned from the Giotto encounter with Grigg-
Skjellerup, which surpassed all expectations.  The quality of the
results obtained during this mission are outstanding and make it
another highlight in the history of Giotto and in the history fo the
ESA scientific programme. 

     ___    _____     ___
    /_ /|  /____/ \  /_ /|     Ron Baalke         | [email protected]
    | | | |  __ \ /| | | |     Jet Propulsion Lab |
 ___| | | | |__) |/  | | |__   M/S 525-3684 Telos | You can't hide broccoli in
/___| | | |  ___/    | |/__ /| Pasadena, CA 91109 | a glass of milk - 
|_____|/  |_|/       |_____|/                     | anonymous 7-year old.
 

Article: 71676
From: [email protected] (Andreas Schulz OT133)
Newsgroups: sci.space
Subject: Lots about Giotto (was: Re: Mars Observer..)
Date: 3 Sep 1993 09:16:17 -0500
Organization: UTexas Mail-to-News Gateway
Sender: [email protected]
 
Subject: Re: Mars Observer Update #2 - 08/31/93
 
[email protected] (Henry Worth) wrote:

|> ...There was one European satellite that was unresponsive
|> for a long time, like a year, but the operators where persistent
|> and eventually communications were re-established and is was
|> reprogrammed for another mission. I don't recall the details,
|> but I think it was Giotto(sp?) prior to the Halley mission,...
 
As far as I remember... OK, you made me curious, so I looked it up:
 
The topic is in full detail covered in an article in the ESA bulletin
73/Feb 1993 : (I've scanned it in, but the full article is some 35k 
long, so I just took out the highlights; blame the OCR S/W for typos;-)
 
-- BEGIN QUOTE -- (with some editorial changes)
 
The Giotto Extended Mission (GEM) - High Risk, High Payoff
 
-  Launched on 2 July 1985 by an Ariane-1
-  nine-month journey towards an encounter with Comet Halley.
-  routine attitude manoeuvres on a daily basis after November 1985
-  Halley encounter operations commenced at 18:34 GMT on 13 March 1986
-  Evidence of the cometary dust had been detected at 23:09 GMT,
   about an hour before closest approach.
-  At -5 sec Parkes lost lock on the downlink, resulting in telemetry blackout.
-  more than 30 min to telemetry was reacquired
-  science operations continued for a further 12 h, at which point
   the experiments were finally deactivated from the ground.
 
Giotto had successfully fulfilled its mission to Comet Halley in a most 
spectacular fashion, but several parts of the spacecraft had been damaged. 
 
By 2 April 1986, Giotto was put into a hibernation mode, with autonomy
features enabled for the detection of possible equipment failures: the
transmitter was switched off leaving Giotto to look after herself,
until return to the vicinity of the Earth in the middle of 1990. 
 
In February 1990, the long process of reactivation was started, Giotto
at some 100 million kilometres from Earth. 
 
At the end of April 1990, spacecraft temperatures had reduced to levels 
at which the experiments could be activated, and checkout began. 
 
The checkout programme showed that, of the original ten experiments,
three were fully functional, three were partly damaged, but usable in
a future mission and two were too damaged to be of any further use
(Halley Multicolour Camera and Neutral Mass-Spectrometer). 
 
At 10:00 GMT on 2 July 1990, Giotto flew over the Earth at an altitude
of 22 000 km, on its way to meet Comet Grigg-Skjellerup on 10 July 1992. 
 
Giotto was put into hibernation mode again on 23 July 1990, 
to remain in hibernation for two years.
 
Second reactivation started at 14:08 GMT on 4 May 1992.
At 01:54 GMT on 7 May, reactivation was essentially complete.
 
Between 8 June and 8 July, all experiments known to be functional
in 1990 were checked out.
 
Encounter operations started some 24 h before closest approach,
scheduled for 15:30:36 GMT on 10 July.
 
Closest approach appeared to occur at 15:30:40 GMT when DSN Madrid
reported a momentary loss of synchronisation.
 
Thereafter, measurements were made on the outward journey until
03:00 on 11 July, when all experiments were switched off.
 
The spacecraft had apparently come through unscathed.
 
Since sufficient fuel was available, final orbit manoeuvres were
performed on 21 July, to put Giotto on another Earth-swingby
trajectory for July 1999. There would not be sufficient fuel for a
further cometary encounter, although possible targets in 2005 and 2006
had been investigated, After completion of the orbit manoeuvre on 23
July, the spacecraft was put into hibernation for the third time. The
final trajectory is expected to bring Giotto to within 219 000 km of
Earth on 1 July at 02:40:26 GMT.  A simplified reactivation
opportunity will occur early in 1999 when, at about 20 million
kilometres from Earth, the spacecraft will pass through a phase in
which the Earth aspect angle is naturally 44.2. lt is, however,
unlikely that Giotto will be reawakened! 
 
-- END QUOTE --
===================================================================
Andreas Schulz          DASA/ERNO Raumfahrttechnik, Bremen, Germany
email:[email protected]     (no clever remarks, intentionally)
 

    re .9
    
    Isn't the original writer mixing up details of Giotto with Olympus?

With maybe a little bit of International Cometary Explorer thrown in?