Author Topic: Redesign the STS  (Read 11400 times)

Offline kraisee

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RE: Redesign the STS
« Reply #20 on: 11/17/2005 06:08 pm »
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rsp1202 - 16/11/2005  8:50 PM

As to Chris' question re: SRB/CLV, the idea of using SRBs as a manned booster has become the linchpin of future manned ops. I've raised the question elsewhere regarding its viability. but have been assured by space "pros" that the booster will be stable in flight, the ride will be benign, and most importantly that the astronauts themselves support the concept.

"Everyone" seems to be for it, even though it's the least talked about part of the new architecture plan. It's considered a "given." Okay. With so many assurances, my concerns have doubled. It sounds a whole lot like the sales job Adminstrator Fletcher was making prior to the shuttle coming online.

So the test schedule for the CLV/SRB becomes the pacing item for everything to follow. The J2 second stage design and test follows that in importance. I worry over that more than whether Constellation and Magnum will ever fly.

The SRB-based CLV has a five main advantages which the Shuttle development project never had.

First, regarding the the SRB's - they have been used a LOT already.   The inherant weaknesses in that particular design (all rockets have weaknesses, the key is making sure they can never cause any problems) are well known and understood.   They have very thoroughly been ironed out of the system over 20 years of continuing development and well over 200 successful ignitions on manned flights.

Second, the cost for the SRB's is significantly lower than any other alternative.   A standard SRB for Shuttle flight cost is about $37m each.   If anyone can find a man-rated rocket, with a proven history, 2m lb of thrust, a burn time of 120+ seconds, recoverable & reusable and built by an American workforce so America can keep the economic benefits domestically for less than that $37m and I guarantee that NASA will talk to you seriously about it.

Third, the main engine for the upper stage is again, already available, fully man-rated and has a long history of successful flights under its belt.   The decision has been made to use an air-start SSME, not the J-2.   It offers greater performance, is available immediately.

Fourthly, the infrastructure is already in place to build both the SRB's and SSME's right now.   The necessary infrastructure is there also to process and launch these systems too (some changes are required at LC-39, but for the most part that involves removing a lot of whats there now instead of building all new stuff), so the speed with which it can be developed and start flying is reduced significantly.

Last but not least, when Shuttle was being developed, the SSME was a brand new engine, never flown before.   So was the SRB.   So was virtually every single part of the infrastructure.   The CLV only requires a new fairing between the stages, and a relatively simple LOX/LH2 tank for the upper stage.   Neither of which are very difficult or expensive to make.   Anyhow, the Shuttle system itself was an awful lot more complicated than these will ever be.   And all these factors add significant cost, vast amounts of extra effort and significantly more time to the development plan compared with teh new CLV.    And most of the staff from the Apollo era were not required to transition across to Shuttle.   This time, the plan is to retain as many of the current workforce as can possibly be retained.

All those factors seem to me to be good reasons on their own why NASA is looking in this direction.   Combined, they bring a very strong argument for the new system to the table.

Ross.
"The meek shall inherit the Earth -- the rest of us will go to the stars"
-Robert A. Heinlein

Offline PMN1

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RE: Redesign the STS
« Reply #21 on: 11/17/2005 06:17 pm »
Would there be a case for reducing the payload capacity of the orbitter but keeping the ovearll booster the same size - how often was the full capacity used in a manned launch that couldn't have been handled by an unmanned cargo pod (if there was one)?

Offline kraisee

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RE: Redesign the STS
« Reply #22 on: 11/17/2005 07:13 pm »
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PMN1 - 17/11/2005  1:54 PM

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Avron - 16/11/2005  11:14 PM

Changes

1) Place the SSME's at the base of the tank and place the Orbiter on top of the tank - inline  - bye-bye foam issue


Whats the refurbishment costs for SSME's (not to mention SRB's) vs expending them each time?

A standard SSME costs about $20m to build and fly once.   They cost about $3m to refurbish each flight.   Performance is best suited to upper atmospheric use, and long burn times.   The SSME-S project would create a disposable variant of the SSME, utilizing lessons learned in the development of both the J-2S and the RS-68 engines used on Delta-IV.   Such a disposable engine, qualified for manned use would cost about $10-12m each.

Shuttle SRB's costs $37m each flight.   I'm not certain of the exact break-down figures for building & refurbishing for each of the 20 flights SRB segments are rated to fly, but that figure is the overall final cost for flying an SRB each time - including recovery.

So "The Stick" will use $37m worth of recoverable SRB, and $20m of SSME.   As long as the stage fairing and the Upper Stage tank don't tip the scales at more than $33m, the whole vehicle will fly for less than $100m - and that makes it very competative indeed as a 21.6MT launch vehicle (to ISS orbit, 220mi, 51.6deg).

For comparison, Delta-IV Heavy can deliver 22.0MT to the same ISS-compatible orbit, but costs $254m to fly, and the largest available Atlas-V, the 551 variant can deliver about 20MT to the same orbit and again costs $254m.

And finally, don't forget that you can easily increase the lift capacity of "The Stick" by upgrading to the five-stage SRB at some point in the future.   That would be very cheap to do, and would increase performance to 24.5MT to the ISS, or 26.3MT to a more Lunar-friendly 220mi, 28.8deg orbit.

Ross.
"The meek shall inherit the Earth -- the rest of us will go to the stars"
-Robert A. Heinlein

Offline PMN1

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RE: Redesign the STS
« Reply #23 on: 11/17/2005 07:22 pm »
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PMN1 - 17/11/2005  1:17 PM

Would there be a case for reducing the payload capacity of the orbitter but keeping the ovearll booster the same size - how often was the full capacity used in a manned launch that couldn't have been handled by an unmanned cargo pod (if there was one)?

Edit - I acknowledge that would be difficult given the booster size would be dependant on the orbitter size but could you successfully argue a case of 'future proofing'?

Offline kraisee

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RE: Redesign the STS
« Reply #24 on: 11/17/2005 07:25 pm »
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PMN1 - 17/11/2005  2:17 PM

Would there be a case for reducing the payload capacity of the orbitter but keeping the ovearll booster the same size - how often was the full capacity used in a manned launch that couldn't have been handled by an unmanned cargo pod (if there was one)?

The Shuttle's useful payload capacity is quite limited actually, at only about 16.5Metric Tons to the ISS.   Yet it costs about $800 to $1,000m to fly each time.   Compare that to the costs I mention in my previous post above and you'll see it isn't very economical.

Further, the payload margins are very very tight right now.

The heavier elements of the Truss section of the ISS already require the Shuttle to have to pull off some special "tricks" in order to make its intended orbit.   For example, the Shuttle has the two smaller OMS engines in the pods either side of the rudder, right?   Well on a lot of ISS construction missions it has been necessary to use them to provide additional thrust during launch - just to ensure the orbiter can make it.   They were never conceived to be used that way, but they do allow the heavy bits of ISS to fly now.

But the fact that they have to use even these engines to fly these days demonstrates very clearly that the tollerances right now are border-line as it is.   Any significant additional weight anywhere in the system means reducing the payload capacity by about the same amount.   Any lower than current levels would mean it would not be able to fly the parts it has to, so any such changes to the Shuttle system between now and retirement are probably out of the question.

Oh, and just for completeness sake, the new Magnum SDLV will be able to lift a whopping 125MT to the same orbit, and will cost only about $500m per flight.   Not bad at all...

Ross.
"The meek shall inherit the Earth -- the rest of us will go to the stars"
-Robert A. Heinlein

Offline Dobbins

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RE: Redesign the STS
« Reply #25 on: 11/17/2005 07:30 pm »
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kraisee - 17/11/2005  1:18 PM

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nacnud - 16/11/2005  7:36 PM

Only if the flight rate increases dramaticaly would some thing like a liquid flyback booster become viable.

EPA are already harping on about the cancerous effects of the perchlorate used in Solid Rocket Fuel (see the article below for one example), so I don't think it will be very long before something alternative has to be designed.

http://www.ewg.org/reports/rocketscience/

If I had to guess, I'd give the current SRB's about ten more years before they'll have to be replaced because of that.

So anyone in the rocket producing business might be wise to start contemplating alternatives fairly soon.   At 2m lb thrust each with a 140 second burn time that's asking quite a lot, but some fairly large LH2/LOX boosters would produce no environmentally damaging effects.   If they could be made easily re-usable, so much the better.

Ross.

In addition to the problems you cited with the unburned perchlorate the SRBs are very dirty from the environmental standpoint. This isn't a major problem with a low launch rate like the Shuttle has and like you will likely see with early use of the CEV. That will change when we get high launch rates. Automobiles weren't a problem when they had a low usage rate but when the rate of use increased beyond the local environment's self healing abilities it became a major hazard. Solid Fuel boosters will become more and more of an enviromental problem as the flight rate rises.

John B. Dobbins

Offline rsp1202

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RE: Redesign the STS
« Reply #26 on: 11/17/2005 07:43 pm »
"The decision has been made to use an air-start SSME, not the J-2. It offers greater performance, is available immediately."

I stand corrected on the second-stage motor, but about being available immediately, has the SSME been tested in restart mode? Thought that was yet to be done. As for the rest, it's hard to disagree with a well-reasoned argument, especially the cost factors, other than by saying all the individual parts have yet to be tested together other than in computer sims. There are a myriad of new components that are still drawing-board sketches, such as solid's new roll motors, guidance package, etc. I believe in "trust, but verify." And give the first crew to ride a solid a cigar.

Offline kraisee

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RE: Redesign the STS
« Reply #27 on: 11/18/2005 02:21 am »
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rsp1202 - 17/11/2005  3:43 PM

"The decision has been made to use an air-start SSME, not the J-2. It offers greater performance, is available immediately."

I stand corrected on the second-stage motor, but about being available immediately, has the SSME been tested in restart mode? Thought that was yet to be done. As for the rest, it's hard to disagree with a well-reasoned argument, especially the cost factors, other than by saying all the individual parts have yet to be tested together other than in computer sims. There are a myriad of new components that are still drawing-board sketches, such as solid's new roll motors, guidance package, etc. I believe in "trust, but verify." And give the first crew to ride a solid a cigar.

There was some testing done early in the program - back on the original Block I's.   Something to do testing if it was possible to re-start an SSME during launch if a hypothetical shutdown problem could be corrected in-flight.   It was never persued to completion, but the engines were certainly live tested for re-start capability and that would certainly have been aimed to be in an air-start mode.

I don't actually think the current Block II's have ever been tested for air-start yet.   But a bunch of Rocketdyne guys I know around here all say its likely the SSME only needs relatively minor changes and it should be good to go, they said once Rocketdyne get a go-ahead, they'd expected it would be ready and fully qualified in about 18-24 months.   To their knowledge, no such contracts have yet been issued though.

Ross.
"The meek shall inherit the Earth -- the rest of us will go to the stars"
-Robert A. Heinlein

Offline Avron

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RE: Redesign the STS
« Reply #28 on: 11/18/2005 02:30 am »
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kraisee - 17/11/2005  1:28 PM


Ross.

PS - Avron, 4 SRB = lots of lift capacity :)   Heh heh heh.

4 SRB would look a lot cooler as a start... hey, money here is no object... No make that a crazy amount of lift capacity..

Edit: cant read...

Offline Avron

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RE: Redesign the STS
« Reply #29 on: 11/18/2005 02:33 am »
Quote
PMN1 - 17/11/2005  1:54 PM

Quote
Avron - 16/11/2005  11:14 PM

Changes

1) Place the SSME's at the base of the tank and place the Orbiter on top of the tank - inline  - bye-bye foam issue


Whats the refurbishment costs for SSME's (not to mention SRB's) vs expending them each time?

Why not.. after all the other changes, this would be a minor cost..:)

Ok, Change number 9 - somehow, need lots of money for analysis (I will do it for the right price), add parachute system to drop off Tank-SSME module..

Offline PMN1

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RE: Redesign the STS
« Reply #30 on: 11/19/2005 09:05 am »
From what i've read, there were disagreemnets between the payload capacity of the orbitter NASA wanted and the payload capacity of the one the USAF wanted - would there be a case for two types of orbitters, a smaller in-line on for NASA and the larger historic side mounted on for the USAF but using as many common parts as possible?

What would be the cost implications of this?

Offline PMN1

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RE: Redesign the STS
« Reply #31 on: 11/19/2005 03:25 pm »
There is an article by Stephen S Pietrobon (Small World Communications) in the May/June 1999 Journal of the British Interplanetary Society about replacing the SRB’s with LRB’s

‘The use of high-density hydrogen peroxide/kerosene liquid rocket boosters for the Space Shuttle is investigated as a replacement for the existing SRB’s. It is shown that H2O2/Kerosine outperforms solids, LOX/Kerosene and LOX/LH2 as a general booster propellant due to its high density and moderate exhaust speed. With the same propellant mass and size as that of the current SRB’s, computer simulations indicate payload mass can be increased by a third from 24,950kg to 33,140kg for a 28.45°, 203.7km circular orbit.'


Offline kraisee

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RE: Redesign the STS
« Reply #32 on: 11/19/2005 06:30 pm »
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PMN1 - 19/11/2005  5:05 AM

From what i've read, there were disagreemnets between the payload capacity of the orbitter NASA wanted and the payload capacity of the one the USAF wanted - would there be a case for two types of orbitters, a smaller in-line on for NASA and the larger historic side mounted on for the USAF but using as many common parts as possible?

What would be the cost implications of this?

Are you refering to the decision back in the 70's or alternatives over the current NASA/USAF disagreement?

If you mean the 70's decision for NASA to make a Shuttle in close cooperation with the USAF, what happened then was entirely due to the very limited budget, and probably had to happen that way.   Nixon was determined that the very last American Astronaut would fly during his Presidency - he wanted NASA closed down.   By getting together with the USAF, NASA probably saved the entire program.   It was unfortunate that it created the compromised launch system we now call Shuttle, but it was entirely necessary just to keep NASA alive.   If you're alive, you can do stuff in the future to change your prospects.   If you're dead, that's pretty-much it.

So I don't think there was the political nor the financial ability to come up with multiple systems for USAF & NASA missions.

On the other hand, if you mean the disagreements between NASA today and USAF today, I think NASA's on the right track and I think the USAF plan to go for a new military Shuttle is destined to failure.   The USAF will see the error of that path soon enough.

By making the simplest and cheapest possible Launch Vehicle for crew use, and then also making a behemoth for lofting big hardware without the enormous expense of man-rating it, you get the best of all worlds for a fraction of the costs.

No matter what the USAF develops, I doubt they'll be able to match the Magnum SDLV's price per pound to orbit rate - and that's what it's all about ultimately - how much it costs to launch stuff.

When you consider that the Magnum will cost only twice as much as a Delta-IV Heavy or Atlas-V bird, yet will be able to launch six times as much payload, you can see the advantages.   It is also based on hardware which has already proven itself.   With that performance available, the USAF would be very wise to let NASA do the R&D work, and then just start buying SDLV's from NASA when required.   That then works for everyone.

I could see some real use for the massive payload size of Magnum by the military too.   Current military spy satellites are limited purely by the size of the mirrors and the focal length of the telescope which can be launched.   For the EELV's the maximum payload width is 5m and the maximum length is around 10-12m, so the entire satellite has to fit inside that.   So I'd guess that the maximum diameter mirror on a satellite today is probably somewhere around 4.5m.   On the Magnum, you could easily put a 12m wide fairing on the top, about 30m long. That would allow for mirrors about 11.5m diameter with a focal length three times current limits.   And that means far, far higher resolution imagery would be possible.

And ultimately, a mega-sized Hubble would also be possible that way too!

Ross.
"The meek shall inherit the Earth -- the rest of us will go to the stars"
-Robert A. Heinlein

Offline PMN1

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RE: Redesign the STS
« Reply #33 on: 11/19/2005 08:48 pm »
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kraisee - 19/11/2005  1:30 PM

Quote
PMN1 - 19/11/2005  5:05 AM

From what i've read, there were disagreemnets between the payload capacity of the orbitter NASA wanted and the payload capacity of the one the USAF wanted - would there be a case for two types of orbitters, a smaller in-line on for NASA and the larger historic side mounted on for the USAF but using as many common parts as possible?

What would be the cost implications of this?

Are you refering to the decision back in the 70's or alternatives over the current NASA/USAF disagreement?

If you mean the 70's decision for NASA to make a Shuttle in close cooperation with the USAF, what happened then was entirely due to the very limited budget, and probably had to happen that way.   Nixon was determined that the very last American Astronaut would fly during his Presidency - he wanted NASA closed down.   By getting together with the USAF, NASA probably saved the entire program.   It was unfortunate that it created the compromised launch system we now call Shuttle, but it was entirely necessary just to keep NASA alive.   If you're alive, you can do stuff in the future to change your prospects.   If you're dead, that's pretty-much it.


Ahh I hadn't realised it was that serious, yes if your partially alive you can try something if you're dead thats it..

Offline PMN1

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RE: Redesign the STS
« Reply #34 on: 11/19/2005 10:29 pm »
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PMN1 - 19/11/2005  3:48 PM



Ahh I hadn't realised it was that serious, yes if your partially alive you can try something if you're dead thats it..

What had NASA done to piss Nixon off so much??

Offline AndyMc

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RE: Redesign the STS
« Reply #35 on: 11/19/2005 10:37 pm »
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PMN1 - 19/11/2005  5:29 PM

Quote
PMN1 - 19/11/2005  3:48 PM



Ahh I hadn't realised it was that serious, yes if your partially alive you can try something if you're dead thats it..

What had NASA done to piss Nixon off so much??

NASA was a creation of the Kennedy administration. Kennedy defeated Nixon in the 196? election and Nixon was known to bear a grudge or two. Plus there was a war to pay for.

Offline CuddlyRocket

RE: Redesign the STS
« Reply #36 on: 11/20/2005 06:48 am »
There always seem to be proposals for replacing solid-fuel boosters with liquid-fuelled ones (those on the Ariane for instance), and yet no-one ever seems to get round to it. A lack of budget, or the do the practical, ease of use, arguments outweigh the theoretical performance gain?

Offline PMN1

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RE: Redesign the STS
« Reply #37 on: 11/20/2005 09:24 am »
If the main engines had been ET mounted from the start, would it have been possible to introduce recovery and re-use that was economic compared to just throwing them away along with the tank?

Offline AndyMc

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RE: Redesign the STS
« Reply #38 on: 11/20/2005 09:46 am »
Quote
PMN1 - 20/11/2005  4:24 AM

If the main engines had been ET mounted from the start, would it have been possible to introduce recovery and re-use that was economic compared to just throwing them away along with the tank?

A tank with or without SSMEs mounted on in would have to be able to withstand re-entry speeds as it gets very nearly into orbit and re-enters the atmosphere over the Indian Ocean.

There were plans for a fly-back Energia variant, but that would have made it a shuttle in its own right.
http://www.k26.com/buran/Info/Energia_HLV/energia_fly_back_booster.html


Offline Dobbins

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RE: Redesign the STS
« Reply #39 on: 11/20/2005 10:57 am »
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AndyMc - 19/11/2005  6:37 PM

Quote
PMN1 - 19/11/2005  5:29 PM

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PMN1 - 19/11/2005  3:48 PM



Ahh I hadn't realised it was that serious, yes if your partially alive you can try something if you're dead thats it..

What had NASA done to piss Nixon off so much??

NASA was a creation of the Kennedy administration. Kennedy defeated Nixon in the 196? election and Nixon was known to bear a grudge or two. Plus there was a war to pay for.

NASA was a creation of the Eisenhower administration and Nixon was the Vice-President in that administration. Nixon wasn't the foe of the space program than some people think he was, he was more like Ike, he supported the general idea but wasn't about to bust the budget on a big program like Apollo. That was something of a culture shock to NASA because too many people in the agency had gotten used to Lyndon Johnson who was the biggest supporter of NASA that ever lived in the White House.

The real enemies of the space program were in the Congress, people like Walter Mondale and William Proxmire. These people damn near killed the Shuttle and if it hadn't gotten the lukewarm support it did get from the Nixon White House it would have been killed off before it ever got started. NASA lost it's biggest supporter in the Nixon Administration when Agnew resigned and was replaced by Ford as Vice-President who was even more indifferent to NASA than Nixon was. Nixon's resignation made things even worse when Ford moved into the White House.

NASA's budget for FY 1973 was 3.324 Billion dollars, adjusted for inflation that would be 14.677 Billion in 2005 dollars, less than it is now but not nearly as bad as things got later. After that year Nixon was politically weakened by Watergate and it's foes in Congress cut the budget down to what would be 12.8 Billion in 2005 dollars by FY 1977 the last budget submitted under the Ford administration.

Things hit rock bottom during the Carter administration. He was so indifferent to NASA that he thought nothing of making it's worst foe his choice for Vice-President. Mondale was in the administration, a vulture who had tried to use the Apollo 1 fire to kill off the Apollo program before it even flew it's first mission, let alone landed a man on the Moon. 3 of the 4 years of the Carter/Mondale administration saw NASA's funding drop to what would be the low 12 Billion dollar range in inflation adjusted 2005 dollars, and fall to it's lowest point since the very early days of the space race when it fell to 11.856 Billion inflation adjusted 2005 dollars in FY 1979.

Things didn't improve much under Reagan. He talked the talk with space station Freedom and the Orient Express but didn't back it with increased funding. The budget stayed at the upper 12 Billion dollar range in inflation adjusted 2005 dollars for most of the Reagan administration until near the very end when funding for a replacement for Challenger bought the first real increases in NASA's budget in a long time. The best thing Reagan did for NASA was hand it's biggest foe Walter Mondale a humiliating defeat in the 1984 election. If Mondale had won then the Challenger accident would have come a little over a year after he took office and I have no doubt he would have done what he tried to do 19 years earlier, use the deaths of American astronauts as an excuse to kill the manned space program they were willing to risk their lives for.

The first President Bush turned out to be the best thing that had happened to NASA since Lyndon Johnson was President. The budget showed real increases peaking at what would be 19.5 Billion inflation adjusted 2005 dollars for FY 1991. Under Clinton it fell again dropping to 15 Billion in 2005 dollars for FY 2000.

John B. Dobbins

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