Conference 7.286::space

    The current problems with the complexity of the space station,
    seem to come from all those required EVAs. (Too many of them)
    
    A simpler station, could just be a station where all the equipment
    is inside the station. Except of course for things that have to be
    outside, such as solar panels and station keeping thrusters.
    (Solar panels and thrusters aren't likely to require any repair)
    
    I hear they are currently moving in this direction, but not enough.
    Even equipment that requires vacuum to work could be inside 
    compartments that only get pressurized when maintenance is needed.
    
    	Gil

    Could station keeping ion thrusters powered by station power work,
    by using gas collected by the station itself.
    
    One of the reasons that station keeping thrusters are needed is
    to compensate for atmospheric drag. The same atmophere that causes
    the drag could also provide propellant to compensate for it.
    
    This could mean a lot, if for some reason the space station had
    to be abandoned for a long period of time. Shuttle fleet grounded,
    etc...
    
    The SKYLAB station fell because it couldn't compensate for drag..
    
    	Gil

	Re: .2

	I like that idea.  Anytime the atmosphere expanded (such as when the
sunspots get active, or more active than anticipated), the space station would
automatically be given even more fuel.  Nice!

	Re: .0

	One "new" idea I'd like to see adopted is a KISS attitude.  To save some
weight, it is being designed for a 400v electrical system so that smaller power
distribution wires can be used.  Have you ever seen a 400v appliance at the
local K-mart?  Every piece of electronics has to be specially designed to
handle the non-normal voltage.  I'd rather see a normal voltage system in use
to cut down the cost of developing the electronics.  (Let any ESA astronauts
bring along a 110v->220v adapter for their shavers... :-)

								-craig

    Well, if you want new idea's, how about this:
    
    I think a space station is premature.  If we are going to build it with
    the shuttle, it will cost 10X what it should.
    
    I think we should either build shuttle II or the aerospace plane first. 
    With more advanced launch systems, that deliver on the promise of low
    $/lb, then you have a chance for a good, affordable space station. 
    Before that, you get an expensive 'techno-turkey'.  I don't really like
    Mikulski, I think she is some kind of Luddite, but I think that is a
    good turn of a phrase.
    
    Tony

re: .-1

Lets build it by using a large gas gun with terminal stage solid booster -
specs say it could put 1000kg per shot into LEO.  I seem to remember few $'s
per pound (I'll look it up).  Put it in Arizona or New Mexico!

Re: .-1

Put the rail gun into Hawaii on one of the volcano slopes so that you don't have
millions of people downrange ducking when something goes wrong with a 1000kg 
mach 25 launch

RE:     <<< Note 646.6 by 39634::REITH "Jim Reith DTN 291-0072 - PDM1-1/J9" >>>
*                              -< Gas or Rail gun >-

*Put the rail gun into Hawaii on one of the volcano slopes so that you don't have
*millions of people downrange ducking when something goes wrong with a 1000kg 
*mach 25 launch

Gas gun has different flight profile from rail gun.  Doesn't require the 
enormous electrical energy outlay to launch.  Doesn't have to be at (over, 
actually) orbital velocity at the start; it's using a solid booster final 
stage.  Much shorter launch tube.  Area from New Mexico to the gulf doesn't 
have a high population density; don't point it across the width of NA continent.
Easy to get to for shipping materials into LEO.  Helps keep prices down all the 
way.  Use destruct device for abnormal launch to protect ground based targets
that may be at risk.

    How about putting the solar panels required to provide power for the
    station in geo-stationary orbit (4 arrays) and beaming the power 
    down to the station ? e.g.
    
    
                     ]o[                           ]o[  <--solar panel arrays
                                .  . .             
                              .        .
                            .            .
                           .               .
                          .                 . <---space station orbit
                          .      Earth      . 
                           .               . 
                            .            . 
                             .         .               
                                . . .
    
                     ]o[                      ]o[
    
    (Excuse my lack of artistic ability)
    
    This would save weight on the station because it would provide a 24hr
    power supply (less batteries) and of course the panels wouldn't be
    attached. The panels would be not be so readily damaged by space junk
    and wouldn't contribute to the station's drag. Microwave's would be
    used to transfer the power.
    
    Brian. 

	Re: .8

	I saw a proposal to do a similiar thing, but with the target of the
microwaves being ground-based receivers to provide energy to the electrical
grids.  It died due to the inability to always guarantee that the microwaves
could be aimed/focused well enough so that the vast majority of the energy
would be directed at the receivers.  The unknown enviromental impact of a
"wondering beam" killed the idea.  What is the impact of this on your proposal?
It doesn't kill it, but there would have to be enough "energy stations" in
orbit so that the microwaves could be aimed at the space station without the
earth being right behind it.  Something like this would be ok:  (and please
excuse _my_ graphics also!)


           Energy Station-( -  -  -  -  -  -  -  - )-space station

                                         +---------------------+
                                        /       earth           \
                                       /                         \


Ok, so the earth isn't hexagon shaped!  Hopefully the graphics were clear
enough to convey the idea that the beam would have to be aimed as a "glancing
blow" that misses the earth.  The biggest problem this creates is the number
of energy stations that would have to be in orbit so that any one is always
positioned well for this aiming requirement.  It would all depend on the
height of the space station, but in LEO I suspect more than 4 energy stations
would be needed.  (Compared to the diameter of the earth, being in a 300 mile
orbit is pretty low when you want to position something in high orbit so it can
look at the space station without seeing the earth as an immediate backdrop.)

	I think the cost of this system, and the time to convince people that
this was safe, would both be prohibitive.

	Instead of putting the energy stations into geo-synchronous orbit, one
alternative might be to put them into a 600 mile or so orbit (excusing the
pun, but just pulling a number out of thin-air).  The drag on the solar panels
would be a lot lower that high up and since the energy station would be so
much closer to the space station, the timing window of when the energy station
could beam the energy to the space station would be increased.  (Although
batteries would still be needed to cover periods when no energy station is
in the right orbital position to "fire".)  A 600 mile orbit is also a lot
cheaper to get than a geo-synch orbit for things this big.

	One question, though.  How big would the microwave receiving panels
have to be?  I'd hate to go through all this effort and cost to end up with
panels that are big enough to still create a lot of drag.

							-craig

    Brian
    
    Good idea, but ...
    
    Even if you only need one power satelite, and you only need one,
    if you use a sun synchronous orbit for the power satelite and if
    the station uses its own panels both to receive sunlight and laser
    light from the power satelite. Its still cheaper to just add more 
    panels and batteries to the station.
    
    I don't remember the exact figure, but around 10 kilograms in LEO
    are equivalent to 1 kilogram in GEO in terms of price.  Worse for
    a sun-synchronous orbit.
    
    Add to that, that you would need some kind of power reception panels
    anyway. You can see that the mass of the batteries (only savings)
    will never be 10 times or greater then the power satelite's mass.
    
    And that is not counting the developement and contruction costs of
    the power satelite. Batteries are much cheaper.
    
    Gil

    RE .9
    
    I too read about the plan to beam energy to Earth based receivers, that
    was seed of my idea. Good point about Earth getting in the way (we
    creative geniuses leave the detail to others ! :-)). If the receiver
    required was too large and heavy then the idea is definitely a
    non-runner. 
    
    RE .10
    
    I think it is a bit unfair to just compare the costs of putting the
    energy stations in orbit and the batteries in LEO. You have to
    provide fuel maintain those batteries in LEO. Also you could use the
    energy stations for other satelites when the space station was not "in
    view".
    
    Which brings me on to another idea, how about having 2 smaller stations
    rather that one large one ? Why ? Because if something devastating were
    to happen, e.g. power failure, shuttle collision, someone didn't test
    it :-) everything would not be lost. 
    
    Brian

	Re: .11

	You are proposing *two* space stations?  You running for Congress from
the Houston district?  :-)  With NASA's luck lately, if they put two in orbit,
they would evade all those little nuts and bolts in orbit and hit each other.

	I still think the power station idea is way too complex and expensive,
but carrying on the discussion in a theoritical nature, I thought of a hole in
my discussion in .9 concerning the placement of the power stations.  My
apologies, but I was thinking two dimensionally.  Approaching it three
dimensionally lowers the number of power stations that are needed.  Imagine
for simplicity sakes that the space station is orbiting directly above the
equator.  If you put the power station in a highly eccentric polar orbit,
it could have a much greater amount of time that it can beam to the space
station without the earth being in the background.  Viewing the world from
the power station's apogee, it would look like the space station is going
around in a circle around the earth.  If the power station could be stopped
at a high enough apogee (obviously silly), it could view the space station
at all times without the earth being behind it.  If you make the power station's
orbit eccentric enough, it would spent most of its time "high enough" to be
able to see the space station.  I'll leave it as an "exercise for the reader"
to calculate the required orbital parameters so that each power station could
see the space station 50% of the time.  (The space station's orbit isn't
directly over the equator, however.  All this means for the power station's
orbit is that the apogee-perigee line has to be orthogonal to the plane of
the space station's orbit for maximum visibility.)

	It doesn't change the orbital calculations, but if this were done in
reality, I'd strongly suggest making the apogee point over the south pole.
Given the potential ability of this power station to transmit energy, several
of our northern hemisphere neighbors (ie. the Soviet Union) might object if
it spent a large majority of its time able to see (ie. fire at) their
territory from a high apogee point.  Making the apogee point over the south
pole not only decreases the amount of time that the power station is over the
northern hemisphere, but also the lower northern hemisphere altitude makes for
a smaller "fireable" footprint at any given time and makes the power station
more vulnerable to antisatellite mechanisms.  (In other words, reverse the
apogee/perigee points from our ICBM early warning satellites.)

								-craig

Say we put a power station into solar synch so it sees southern hemi of earth
and equitorial station(s) most of the time.  (It could also be used to power 
orbital tugs, BTW.)

Why do we need the space station in a geosynch orbit?  Are the planned station 
modules going to be the external tank of the shuttle?  Has a cost/benefit 
analysis been done on that?

What if we move several of the external tanks to a L(n) point?

What if we use a gas gun to launch fuel into LEO so an F1 engine or equivalent
taken up by the shuttle (if it'll fit in the bay) could be used to boost the
external tanks into MUCH higher orbit (maybe L(n)?)

???????

    
    	Re: .13
    
    	I don't think anyone has proposed putting the space station in
    geosynchronous orbit.  Besides the fact that the shuttle couldn't
    possibly reach that orbital level, the costs of just boosting the space
    station to geosynchronous orbit would be astronomical.  (Not that cost
    factors seem to have ever stopped NASA before... :-)
    
    								-craig

RE:                      <<< Note 646.14 by 19574::YANKES >>>
*                  -< Geosyn?  Nah, perhaps a 300 mile orbit. >-
*    	I don't think anyone has proposed putting the space station in
*    geosynchronous orbit.  Besides the fact that the shuttle couldn't

I was thinking of .9's comment on solar power stations in geosynch orbit while 
I was typing and sorta crossed it over in my mind.

*    possibly reach that orbital level, the costs of just boosting the space
*    station to geosynchronous orbit would be astronomical.  (Not that cost

Course, now that you mention it, while it would be expensive using our current 
tool set, lets propose a different tool set where it wouldn't be very expensive.

Ideas?

    Here is another idea...
    
    I propose that a 2 stage "expendable" rocket is built to assist the
    shuttle in transporting the equipment required to build the space
    station. Nothing new there, however the second stage should be made so
    that if fits inside the shuttle payload bay. The rocket would be
    launched each time a shuttle is launched, and then having been emptied
    of its cargo would be loaded into the shuttle for return to earth and
    subsequent re-use ! A semi-expendable.
    
    I call this the Shuttle Compliment Rocket. It would reduce the 28
    shuttle launches (hope thats correct, from memory) required to build the
    station. 
    
    Brian.                               
    
    

RE:.16

How about a couple more SRB's on the external tank. I seem to recall some 
mention of this for heavy missions, but then there are not 60 flights a 
year yet either!

	-SES

    Re:.17
    	Back in the late 70s and early 80s there were a whole bunch of
    ideas to boost the shuttle's payload capabilities. They included
    augmenting the SRBs with smaller solid rockets attatched, a resusable
    propulsion module (based on the Titan III core stage technology)
    mounted at the base of the external tank, various modifications to the
    SRBs themselves (e.g. replacing the metal casings with composite
    casings), and substantially uprated SSMEs (something like 140%) as well
    as others. I've never heard of plans to add SRBs to the basic Shuttle
    stack (the Soviet's Energia launch vehicle has that capability) but I
    wouldn't be suprised that it appeared on some vendor's drawing board
    somewhere.
    
    				Drew
    

	Re: .15

>Course, now that you mention it, while it would be expensive using our current
>tool set, lets propose a different tool set where it wouldn't be very expensive.

	Well, I guess we could start by ECOing the laws of gravity... ;-)  No
matter *what* tool set we create, the cost of going to geosynchronous orbit
will be much higher than the cost of going to low earth orbit.  Unless, of
course, we find a propulsion mechanism by which the more energy you get out of
it, the less energy had to go into it.  Not too likely.

	Besides, what are the benefits of having the space station in
geosynchronous orbit?  Unless someone can come up with some good reasons, I'd
put this whole "how to do it" question in the pile of "technologies in search
of problems to solve".  And no, geosynronous orbit is not the solution to the
space station needing period reboostings to maintain orbit due to atmospheric
drag.  A 500 or 1000 mile orbit would help almost as much as going to the
expense of a geosynchronous orbit.

								-craig

	Re: upgrading the shuttle with other boosters.

	I'd be against any of the upgrades mentioned.  All they would do is take
an already overly complex launch entity that is difficult to approve for launch
due to carrying people aboard, and add more complexity to it.  I'd much rather
see the effort going into developing better heavy-lift expendibles and leave
the shuttle for things that _absolutely_ need to have people on board for.

								-craig

RE:                      <<< Note 646.19 by 19548::YANKES >>>
*     -< But what is the problem that a geosynchronous orbit would solve? >-
Craig,
I already mentioned in .15 that I was responding to a nonissue wrt GSO.

*>Course, now that you mention it, while it would be expensive using our current
*>tool set, lets propose a different tool set where it wouldn't be very expensive.

*	Well, I guess we could start by ECOing the laws of gravity... ;-)  

Wouldn't that be a Field CO? 8*)

*No matter *what* tool set we create, the cost of going to geosynchronous orbit
*will be much higher than the cost of going to low earth orbit.  Unless, of
*course, we find a propulsion mechanism by which the more energy you get out of
*it, the less energy had to go into it.  Not too likely.

From an energy standpoint you are correct.  I was speaking from a dollar$ 
standpoint.  Are youse guys stuck on chemical rocket technology?  Do you suffer 
from NASA bureaucratese?

*	Besides, what are the benefits of having the space station in
*geosynchronous orbit?  

Other than the obvious (staying put over one spot of the planet) I don't know 
off hand.  But then, I'm not saying we need a GSO space station.  I'd much 
prefer several cheapie LEO's and a few Cheapie LLO's, with a phobos/diemos 
site...

*Unless someone can come up with some good reasons, I'd put this whole "how 
*to do it" question in the pile of "technologies in search of problems to 
*solve".  

Why'd we go to the moon?

*And no, geosynronous orbit is not the solution to the space station needing 
*period reboostings to maintain orbit due to atmospheric drag.  

That wasn't proposed.

*A 500 or 1000 orbit would help almost as much as going to the expense of a 
*geosynchronous orbit.

Then you start to think more about shielding, don't you?  Which, if we're stuck 
in the chemical rocket rut, increases the dollar expenditures dramatically.  As 
you pointed out, higher energy cost for a higher orbit; which runs into big 
bucks with chemical rockets.

My whole point in starting this note was to see who would be interested in 
discussing alternative methods WRT the space station (and anything else for 
that matter) which would achieve a similar (or different) result more cheaply or
more safely or produce more spin-offs, etc.

>I'd much rather
>see the effort going into developing better heavy-lift expendibles and leave
>the shuttle for things that _absolutely_ need to have people on board for.

  Hear hear.  But I'd like to go one step further.  Scrap the shuttle.  It's the
wrong solution.

  What would it take to get the physical minimum payload of, say,
a crew of 10 into LEO?  This means sufficient life support to get up and back
down (to handle a failure on the way up or to bring the in-orbit crew back).
This system would have no goals except actually transporting the crew up to
their destination, hypothetically a space station.  Not a space truck, but a
space cab.

  Such a system should be complemented with a heavy-lift system which moves
material to the space station which need not be man-rated.  This could mean
the various 'guns' that are being discussed - for raw materials, and traditional
rockets for more sensitive materials.

  This brings up a separate question.  What materials need to go up on man-rated
boosters?  Anything?

  Anyway, given a threesome of a man-rated transport system coupled with a
cheap, reliable system like a rail gun and a dumb heavy-lift rocket, it would
seem that we'd be in pretty good shape to get the necessary stuff in to orbit.
Each system would be geared very much toward the one problem that it was trying
to solve and, hopefully, reduce the overall complexity and tradeoffs that are
made when doing too much with one system.

  Also, this would allow us to gain expertise in each of the lifting areas:

  1. Man-rated systems for shuttling living beings around.  That's all that they
would do.  My believe is that a hybrid air-breather/rocket is the way to go, and
the low payloads and short mission spans of a 'cab' may make that practical.

  2. Material movers for getting stuff into orbit as cheaply as possible (where
non-trivial losses are acceptable).  The launch process would probably result in
very large accelerations and very simple launch vehicles (vehicle may be too
sophisticated a term).

  3. Material movers for getting stuff into orbit in a reliable manner.  Losses
are far less acceptable since these systems would be putting satellites into
orbit and the things cost money.

  Reusability of the first and third systems would certainly seem desireable
considering the cost that will go into them to make them reliable (or is that
a misconception? - that reliability does not infer cost)

John

	Re: .21

>Wouldn't that be a Field CO? 8*)

	Oops, of course...  Sorry for that slip-up!  I'd love to see the
logistics needed to implement the FCO all across the universe at the same
time.

	Ok, getting back to being a bit more serious...

>From an energy standpoint you are correct.  I was speaking from a dollar$
>standpoint.  Are youse guys stuck on chemical rocket technology?  Do you suffer
>from NASA bureaucratese?

	First off, when talking about orbits, energy=dollars.  It could be
chemical, solar sail, rail-gun, you name it, but the higher up you want to
put it, the more energy and cost has to go into it.

	Secondly, I really resent the "do you suffer from NASA bureaucratese"
comment.  Frankly, if the whole program was up to me, I'd cancel the whole
thing.  Cancel.  Period.  No more space station.  Zip.  Wait until we can
*afford* the beast (sheeze, folks, we *are* the world's largest debtor nation!)
and then consider it.  I seriously doubt that philosophy would get me counted
in as suffering from "NASA bureaucratese".  Please, lets discuss ideas but
don't get into personal attacks.

>off hand.  But then, I'm not saying we need a GSO space station.  I'd much

	You're right, you slipped up between "space station" and "power station"
and when I made my .19 reply, I was still thinking you were talking about
putting the space station in geosynchronous orbit.  Apologies and item dropped.

>Why'd we go to the moon?

	To prove our "might" by beating the Soviets to the moon.  They scared
our military when they launched Sputnik, and we wanted to prove that we were
a much mightier nation.  The two biggest differences between back then and
now are:

	1)  If we are supposedly cooperating with the Soviets on future
activities, there is no need to have yet another space station launched. Unless,
of course, we just feel the need to prove our national manhood.  (Sorry, ladies.
:-)

	2)  Back in the 60s, we could afford the moon effort.  Today, we can't.


	Getting back to the topic of ideas...

	Something I've been thinking about for a long time would be, for lack
of a better phrase, a centripedal launcher.  It could be a long bar-shaped
item with masses at both ends -- sort of like this:


         ***                                 ***
        -***---------------()----=-----------***-#
         ***                                 ***

where:

	"-" represents the bar (of pretty good length, several miles?)

	"*" represents a mass that is movable along the bar

	"()" is the central control station (manned, undoubtedly)

	"=" is an "elevator" that can hold a payload and take it out to the
	    payload handling device.

	"#" is a payload handling device.


	This gets put into a low earth orbit and it rotates "end over end"
(ie. the picture above is like looking at it from the side and the bar would
rotate in the plane of the terminal screen).  Payloads to be boosted to higher
orbits would be transferred to the "elevator" at the central control station.
(Which, being in the middle, won't have much centripedally-enduced gravity
to work against.)  The elevator transfers the payload out to the payload
handling device (something that just holds it in place against the gravity).
Once it is secured, the masses can be pulled inwards, which would increase
the rotation speed of the entire entity.  Once the ends of the arms are moving
at the desired payload release velocity (which would be the orbital velocity
of the entire station plus the radial velocity of the rotating arms -- for the
"top" of the rotation where the payload is traveling tangentially to the earth
in the direction that the station is rotating around the earth in), the payload
is released.  Off it goes.  The payload would still need a rocket to insert
itself into the final circular orbit (unless, of course, there was a
centripedal launcher at that orbit to catch it :-), but at least the initial
boost-phase can be done without a rocket.

	After releasing the payload, the centripedal launcher could move the
arm masses back to the end to slow the rotation back to a "normal" speed in
which work can be done most easily.

	If you got real good at timing things, you wouldn't even have to take
the payload up to the launcher in a circular orbit.  When the end of the
arm is moving tangentially to the earth, but "against" the direction of the
launcher's orbit, the end of the arm is moving significantly slower than 
is the overall launcher.  This means that a payload put into an elliptical
orbit whose apogee meets the arm could be "caught" by the centripedal launcher.
(ie. For the "docking", the payload would *not* have to be in the same orbit
as the launcher.  Elliptical orbits with an apogee of X miles is much cheaper
to achieve than is a circular orbit of the same apogee.)  The payload would have
to be able to deal with the sudden acceleration as it was caught, however.
I'll leave that as an exercise for others to work out...

	There, satisfied that I'm not "chemical rocket happy"?

								-craig

I've read somewhere about how tethers could be used to extract energy from the
Earth's gravitational field to transfer payloads to higher orbits.  It's too bad
I can't remember where I saw this.  Can anyone help out and fill in the details
as well as correcting any misconceptions?

Wook

    	See Topics 451 and 547.
    

RE:                      <<< Note 646.23 by 19548::YANKES >>>
*            -< Me?  Suffering from NASA bureaucratese?  Good joke! >-

*	Oops, of course...  Sorry for that slip-up!  I'd love to see the
*logistics needed to implement the FCO all across the universe at the same
*time.

Piece of cake (for an arbitrarily advanced civilization) 8*).

*>From an energy standpoint you are correct.  I was speaking from a dollar$
*>standpoint.  Are youse guys stuck on chemical rocket technology?  Do you suffer
*>from NASA bureaucratese?

*	First off, when talking about orbits, energy=dollars.  It could be
*chemical, solar sail, rail-gun, you name it, but the higher up you want to
*put it, the more energy and cost has to go into it.

True, but I was refering to the idea of a cheaper method to orbit (as opposed 
to chemical rocket technology) and if the cost per pound is a few bucks then 
what does it matter (that much) as opposed to the current multi-thousand dollar 
per pound cost?  And this is refering back to a note that I've forgotten the 
details of (10 or 15 back?) - but my basic idea was, it might cost alot using 
chem rockets but does that mean it'll always be that expensive using other 
methods?  I didn't think so then and don't now.

*and then consider it.  I seriously doubt that philosophy would get me counted
*in as suffering from "NASA bureaucratese".  Please, lets discuss ideas but
*don't get into personal attacks.

No offense intended.

I think we could learn a lot by putting up several cheaper space stations.

*	There, satisfied that I'm not "chemical rocket happy"?

I guess so. 8*)

BTW, the centripetal launcher you were thinking of is also known as a 'rotating 
endwise orbital tether'.  We don't yet have the materials to build the other 
kind on Earth (a 'gravity-gradient stabilized Orbital tether', 'beanstalk', etc)
but we could build one of the former today if we could get enough payload into
orbit.  That's why I wish we'd go after the cheap and simple gas gun launcher as
opposed to a railgun engine or mass driver.  We don't tie up billions and we 
can do it today (or tomorrow at the latest.)

Tim

    Re: .22
    
    I disagree with your suggestion to scrap the shuttle. With the
    extremely long development time associated with US Aerospace
    engineering efforts, we are a minimum of 10 years away from any possible
    operational shuttle replacement. That would give us a 10-year hiatus
    from manned activity and continue the decline of space experience
    to the US space program.
    
    I DO agree that the shuttle is more expensive than expected, and
    the return on investment has been substantially less than originally
    touted. We need a replacement, but not at the expense (lost dollars,
    lost science, and lost opportunities) of scrapping a system that
    works.
    
    We need to develop the "Aerospace plane" (or something with similar
    capabilities) for manned LEO missions and Space Station crew transfer.
    We also need a heavy-lift capability for unmanned deep-space missions,
    GEO payloads, and possibly to carry manned interplanetary (Moon, Mars,
    etc) mission equipment for assembly in LEO. The shuttle MAY even
    continue to have a role for complex LEO short-duration missions
    with heavy, highly complex payloads that need the additional
    flexibility that men on-board provide.
    
    Personally, I'd also like to see a Space Station resupply capability
    similar to the Soviets'! It seems to follow the "KISS" concept,
    and it works.
    
    John B. 

>    I disagree with your suggestion to scrap the shuttle.

  Although I threw around words rather casually, 'scrapping' meant identifying
the shuttle as a good idea, but not a practical one.  It meant that we need to
be thinking about stepping back and rethinking the way we want to go into space.
Apparently, the shuttle is just too darn complicated when it just isn't
necessary.  I'm not sure that I'm all that thrilled with the idea of the
National Aerospace Plane.  It's another high-visibility, push-me-pull-you sort
of project that just has too much riding on it.  We need some KISS systems and
I think that the experiences from the shuttle will allow us to do that because
now we know what 'too complicated' means, and where the complications hurt us
and what we could actually get away with.

  That's the long form of 'scrap the shuttle'.  :)

  It can't happen tomorrow, but it should be a goal of the space program to
phase it out pretty quickly (as appropriate given a replacement system or set
of replacements).

>With the extremely long development time associated with US Aerospace

  These extremely long development times come from massive complications and
arrogance on the part of US engineering companies who are out to make a buck.
I *know* that quality vehicles can be constructed in aggressive timeframes,
particularly now that the shuttle has been built.  Kelly Johnson and team took
something like 18 months from drawing board to production for the U-2.  Johnson
had other such successes of fast turnaround.  It's a question of will.

  Think of it as just another problem with the space program.  Our believing
that that's the way it has to be won't help.

  The shuttle should have been called the X-32 program, because it certainly
was and is an expermental program.  Other experimental programs led up to this
to prove the concepts (lifting bodies, reaction control systems, countless
experiments and models of the various systems and components).  But the experi-
mental aspect of the shuttle is the raw complexity - the logistics of doing
something like the shuttle.  That is perhaps the largest experimental aspect
of the shuttle and the one which is turning out to provide the most problems.
The technology works.  It's keeping it all hanging together that isn't working.

John

    RE .16
    
    I've been trying to devise a way of making my semi-expendable shuttle
    compliment rocket fully reusable. This is brilliant :-). The first
    stage of the rocket is equipped with rotors similar to a helicopter (o.k.
    stop laughing until you read to the end of the note !) which during
    liftoff are folded into the body of the rocket. The rotors spring up
    from the sides of the spent stage causing it to spin slowly back to earth
    much like the seed of a sycamore tree.
    
                         -----
                        |     |
               ---------|     |--------   <- rotors
                        |     |
                        |     |
                        |     |
                         -----
                         /   \
    
    By controlling the pitch of the rotors relative to each other it should
    be possible to steer the rocket to a suitable landing site.
    
    Why not use parachutes ? Good question, why aren't parachutes used to
    recover and reuse the early stages of conventional rockets ?
    
    Brian.

>    Why not use parachutes ? Good question, why aren't parachutes used to
>    recover and reuse the early stages of conventional rockets ?
 

I wish I knew more about rocket design, but I can render a few guesses on
this question.

Most rockets are designed to push the most weight into orbit for the least
cost.  To do this, you keep the weight of the launch vehicle as low as possible.

A recoverable vehicle must be capable of withstanding both launch and recover
stresses (the latter being a far bit more nasty).  Have you seen those big
rockets?  You can put your fist right through them (O.K., you can jam a
screwdriver in).  That kind of construction doesn't survive a landing.
Look at the SRB casing.  Big, thick, *heavy*.


Next you have to consider what is reusable.  The fuel tanks, the engines?
Most rocket engines have a limited life span (measured in seconds).  There
are those that have multi-hour ratings - but I'll bet there is a cost there
too (plus they have to survive hitting dirt or getting a salt-water bath).


A lot of these ideas that are being discussed are really neat, and I'm
really impressed with a lot of them.  What they lack is some definitive
cost estimations (and proof-of-production-feasibility for some) so I have
some difficulty translating them into practical suggestions.  I'd love to
know if the people who design/build rockets for a living brainstorm like
this over lunch -- now *that* would be a fun place to dine.

Onward,

- dave

    Re: .29, .30

    As NASA was trying to choose in the late 1960s between big dumb
    boosters (and slightly smarter manned vehicles boosted by them)  and
    advanced reusables (like the early Shuttle concepts), it looked at
    rotor-based recovery for manned spacecraft (mostly lifting body types). 
    It was believed that a retractable recovery rotor would add a great
    deal of unwanted weight and complexity to a space vehicle, although
    there were no unsurmountable technical barriers to building such a
    system.  Unpowered glide landings were considered the simplest was to
    recover, followed by a powered landing (from an operational 
    standpoint, a vehicle that is powered at landing is most desirable,
    because of its flexibility, but of course the complexity and cost is
    much higher).

    Guided parachute recovery of large vehicles (like boosters) is
    well-understood but very limited operationally; guidance of a
    parachute or parawing vehicle is a non-trivial problem.  It can be
    done; in fact most of our air-dropped nuclear weapons are really
    rocket-boosted guided missiles that use parachutes for lift and
    control.  But obviously, recovery is not an issue :-).

    One concept that keeps popping up every ten years or so is the idea of
    shaping the booster like a king-size Apollo command module
    (technically, that shape is known as a blunt body , or low L/D lifting
    body).  There were several proposals in the glory days for heavy lift
    boosters in this configuration.  Chrysler's original ASSC study
    (alternative shuttle concepts, 1969-70) was for a single stage reusable
    booster in this configuration, with an 85,000 lb. payload to LEO. 
    Grumman and Boeing also looked at this setup in the late 1970s for very
    heavy lift freighters to support solar power satellite construction. 
    The idea is to recover the booster exactly as you would recover an
    Apollo command module, although the final deceleration for landing
    might be done by retro-rockets rather than parachutes, with the vehicle
    landing on land or water.  One disadvantage is the decrease in usable
    mass fraction due to loss of staging efficiency (it's basically a one
    stage vehicle). 

    The current Navy SEALAR (Sea Launch and Recovery) program may
    incorporate aspects of this design, although I've see nothing that
    describes the configuration the Navy is working on.

    This seemed the best place to put this. (If not, mod. please move.) 
    With all the discussion about the station and it being too complex to
    build/maintain and too many launches to get it there in the first
    place, are there some things that could be done NOW to simplify things
    a bit?  By this I mean, there are some itmes that any station, however
    complex or simple, simply must have; these being fuel, water,
    atmosphere (inside ;^), and other consumables.  Couldn't quantities of
    these items be launched today in sealed containers via the shuttle and
    "stocked" in orbit for when they will ultimately be needed? Is this
    feasible?
    
    Not all shuttle payloads are the same size/weight and this implies to
    me that there is extra room for such cargos assuming the shuttle has a
    constant as a launch capacity.  I realize this would mean that the
    shuttle would have to be in an orbit very similar to that of the future
    station and that not all shuttle flights are in the same orbit.  But
    isn't there some consistency that would make such a plan feasible? 
    Also there would have to be some means to keep there space "care
    packages" together.  (magnetic?)  Deployment could be dones by the arm
    so as to eliminate EVA.  
    
    Is this a realistic idea or just wishful thinking?  Comments.

    Why don't we give Burt Rutan a couple hundred million and let him
    design us a shuttle? Part of our problem is that we go to ridiculous
    lengths to safe guard human life, mostly in the realm of agonizing over
    design. One of the problems with the shuttle is that the quality and
    strength needed sit on top of a controlled bomb 20 or 30 times is much
    greater than doing it once. In retrospect it would have been cheaper to
    make an assembly line booster and spend the research money on
    incremental improvements.
    	 Since exotic fuels are part of what makes
    launches so expensive, why don't we buy the SST(its uneconomical anyway)
      and sling  a space plane under the wing. Using jp4 to reach mach 2
    and 40,000 feet should cut back on launch costs.
    
    john