Remembering – Thoughts on Space

Editor’s Note: we saw today the passing of NASA astronaut Bruce McCandless, the first person to fly freely and untethered in space. He was 80.

Regular followers of Dr.Pournelle know that he was passionate about exploring space. So we dug into the archives and picked this one (there are many to choose from) written Wednesday, June 11, 2003. There are many links to other pages; some of the links may have ‘died’ due to the passing of years. We’ve only added some minor formatting changes.

Readers are invited to discuss these issues; many things have not changed in the years since. Use the comments area at the end to add your thoughts on this subject.


I can solve the space access problem with a few sentences.

Be it enacted by the Congress of the United States:

The Treasurer of the United States is directed to pay to the first American owned company (if corporate at least 60% of the shares must be held by American citizens) the following sums for the following accomplishments. No monies shall be paid until the goals specified are accomplished and certified by suitable experts from the National Science Foundation or the National Academy of Science:

1. The sum of $2 billion to be paid for construction of 3 operational spacecraft which have achieved low earth orbit, returned to earth, and flown to orbit again three times in a period of three weeks.

2. The sum of $5 billion to be paid for construction and maintenance of a space station which has been continuously in orbit with at least 5 Americans aboard for a period of not less than three years and one day. The crew need not be the same persons for the entire time, but at no time shall the station be unoccupied.

3. The sum of $12 billion to be paid for construction and maintenance of a Lunar base in which no fewer than 31 Americans have continuously resided for a period of not less than four years and one day.

4. The sum of $10 billion to be paid for construction and maintenance of a solar power satellite system which delivers at least 800 megaWatts of electric power to a receiving station or stations in the United States for a period of at least two years and one day.

5. The payments made shall be exempt from all US taxes.

That would do it. Not one cent to be paid until the goals are accomplished. Not a bit of risk, and if it can’t be done for those sums, well, no harm done to the treasury.

I had Newt Gingrich persuaded to do this before he found he couldn’t keep the office of Speaker. I haven’t had any audiences with his successors.

Henry Vanderbilt points out that having a prize, say $1 billion, for the second firm to achieve point (1) above will get more into the competition, and produce better results. I agree.


SSTO discussions. Continued from last week:

I was an SSTO fan for many years. Now I am skeptical to the point of seeing reusability–on the launch vehicle level at least–as a fetish arising out of undisciplined thinking. Given the current state of technology, it just doesn’t make any engineering sense to put into space anything that isn’t going to stay there, no matter how valuable/rare it is perceived to be. The one exception is, of course, humans.

For this reason, I think NASA should develop a minimum mass/size reusable crew vehicle for 6-8 personnel, designed to be flown as a payload on current heavy lifters. NASA should then buy launch services for these vehicles and other Administration cargoes on the open market. Only after securing future manned spaceflight capabilities on such a rational platform should NASA spend any money on next-gen stuff.

Sorry, Jerry…I know what you believe, and I understand why, but first things first. US manned spaceflight is ready to go down the drain because of over-reaching and fuzzy thinking. Let’s get it working again before trying to leap ahead.

Tony Evans

Thank you for sharing that with me. Let’s see: you think I am a fetishist for wanting an SSX X-program, while you will trust NASA to develop an entirely new kind of “man rated” ship to be flown off expendables, and to do that in some reasonable time frame.

I see.

As to your first revelation, that it makes no sense to put anything in space that doesn’t stay there, that may be true, but it says nothing about costs of getting it there. On the face of it, throwing away the rocket is a pretty expensive proposition: it may be the right idea, but it’s not intuitive. The intuitive notion is to have ships whose cost of flight is fuel driven. Granted, if rockets — motors, avionics, fairing, the whole magilla — were free then expendables would be the obvious way to go because the launch costs would be related only to the fuel costs. The point is that they are not free. Moreover, big dumb expendable boosters — one of the serious alternatives to reusable space ships — have the inherent problem that all the payload goes to one orbit. You need means of redistributing packages to where you want them after they get there. Sometimes that is not a problem. Sometimes it is.

In other words, the concept of reusable spacecraft comes out of an operations analysis — greater flexibility of space operations, and thus making more missions possible — and pure cost analysis. On that last: “man rating” of expendables is very expensive for obvious reasons. “Man rating” of aircraft is done differently, as it would be for space ships that have flown many times. Which would you rather ride to space and back: a ship which has, itself, flown to space and back fifty times without being disassembled between flights; or a ship that has made 28 flights in over 20 years, and was so thoroughly “refurbished” between flights that much of it was in essence a brand new ship each time?

Reusable ships are tested for reliability by flying them. Expendables are “man rated” through analysis.

I realize all this seems fetishistic, but I at least think it’s just analysis.

“I think NASA should develop” says Mr. Evans. Why NASA? Why not private business?

NASA is a research and development organization. NASA needs to stop pretending that the shuttle is a routine vehicle, recognize that it’s an X-plane, and simply let a one-page RFP for a space plane, which it then purchases the services of. NASA needs space planes from different companies. Federal Express doesn’t just use one kind of airplane to do business; neither should NASA.

While the space agency has good people and is splendid at doing research, it’s NOT A BUSINESS. Everyone needs to recognize that. Yes, I’m part of a company that wants to sell vehicles to NASA. NASA should spend its money on training and exploration and the things it does well, and let private enterprise do what it does well.

Aleta Jackson XCOR Aerospace

Private industry in the aviation world at least has always benefited from government research and development. The government is far better suited to fund X projects than private capital: by definition X projects have no goal but developing new technology, and they balance risks against that payoff — but they have zero chance for immediate profit. Few private companies want to invest in technology research at the billion dollar level, with the only possible payoff to be exploitation of that technology in future down the road projects.

What private industry does well is to take existing technology and make usable products from it. Sure, there are cases like Intel in which the technology development is itself part of the business plan and profit cycle of an industry. That also drives marketing, and costs.

The drug business is in a constant battle between private development for profit (and exploitation of the ones that pay off) and government labs doing some of the same work: no one has ever done a good analysis of the cost/benefits of a government X program in drugs. It might be very high leading to lower drug prices.

We’re of course agreed and always have been that NASA shouldn’t be in the vehicle development business, nor should it be operating spacecraft. Those are all functions for either private companies selling launch services, or the military who have to learn to do routine operations in space — one thing the military must do is practice doing in peace time things they have to do in war; it’s no time to learn how to operate a mess hall or supply system when people are shooting at you, and that’s no time to learn how to get to space.

This is a long answer to a letter with which I mostly agree and issues which you and I have discussed before: most readers probably know that Richard Pournelle is a VP of XCOR, and that if the government adopts the programs I advocate, XCOR will almost certainly be a big part of them. After all, X projects themselves need to be done by private companies: we don’t want to build big government factories and arsenals of space. But the old NACA was in fact pretty influential in guiding the development of the aerospace industry, operated big wind tunnels that no single company could afford to build and maintain, and through the X-1 through X-15 programs took us a long way.

Government does some things well. X Projects have historically been one of them. The disaster comes when a private company captures an X project like X-33 and twists it into something entirely different. Bureaucracies tend to work in their own interest, and that is no less true at Lockheed than at NASA. Privatization is the sure for many ills but alas not for all of them: we need a way to develop space technologies. In particular we need a follow on to the RL-10 engine, and to learn a lot more about the plumbing of multiple engine reusable rockets.

XCOR likes wings a lot more than I do, but certainly we need to learn more about the use of wings; and 2STO will certainly work even if SSTO turns out to have too small a payload per mission. All of these are still technologies, and need to be developed, and funding their development is a reasonable task for government.

Adam Smith said it is a proper role of government to fund those great enterprises which have high risk and high payoff for the nation, but the payoff to any one individual or group is not high enough to justify the cost. He had in mind canals and roads (as did the Constitution with Post Roads being a specific power of Congress); but X Projects fit that model just fine.

Of course prizes might do the job as well.


The debate on SSTO (Reusable space ships, or Single Stage to Orbit) continues. Note that despite the tone of some of these letters, SSTO is not absurd, and has the support of many experienced rocket engineers, including the late Max Hunter. For political reasons NASA has always said it was too silly to study — else why hadn’t they ever done anything as simple as the DC/X as a research vehicle?

The report of the Council which recommended X projects leading to an SSTO vehicle, go here. The basic rocket equation discussion of the concept is here. There’s math in there, but not too much. The concept of X projects and their importance for getting to space, look here. I have repeated this short introduction below. Eventually I will collect all this material into ahref=””>see here.

Dear Mr Pournelle:

I’ve been a great admirer of your for more years than either of us would care to count and I credit you for teaching me as much about science as my college professors. However, I’m rather surprised by your enthusiasm for a Single Stage To Orbit launcher.

If we were talking about using advanced propulsion technology such as supersonic combustion ramjets I’d share your opinion. However, most SSTO proposals envision using conventional rocket engines. The multistage rocket systems that are currently being used aren’t a fashion statement, they are a reluctant adaptation to the performance limitations imposed by the basic physics of rocketry.

As you are well aware, the mass of fuel required for a mission rises exponentially with the ratio of the delta-vee to the specific impulse. The minimum, theoretical mass ratio for a rocket to reach earth orbit is about nine-to-one using LOX and Hydrogen. Because the low density of liquid hydrogen would require enormous fuel tanks that would be either extremely massive or to fragile to survive reentry, other fuels such as liquid methane or liquid propane would be more feasible.

However, the mass ratio required with these fuels would be around twenty-to-one. Rather than demand revolutionary advances in rocket technology, why not adopt an evolutionary approach. Since the loss of the Columbia will force NASA to at least consider building a replacement orbiter, we have the opportunity to redesign the vehicle to incorporate either Titanium or advanced, high temperature composites in its structure. We might even use an active cooling system that would make the thermal tiles unnecessary.

Of course the highest priority would be to redesign the orbiter to include modular systems with a much longer service life that would minimize the maintenance required between launches. The next logical step is to replace the solid fuel rocket boosters with liquid fuel boosters that fly back to land on a runway rather than drop into the ocean. As you remember, the original design of the shuttle included a liquid fuel, fly back booster which was abandoned because it was so massive.

Using twin, flyback boosters that are compatable with the existing STS configuration offer a number of tantalizing possibillities. Because the entire orbiter, fuel tank and boosters assembly is quite light until it is fueled on the launch pad, we could adopt the Russian practice of horizontal assembly. This approach is proving to be very cost effective for Boeing. Secondly, using twin, liquid fueled, flyback boosters for the Shuttle offers the possibility of using them as components for a modular, heavy lift vehicle. You could put 100 tons into orbit simply by replacing the orbiter with an expendable payload faring and propulsion-avionics module that is packaged in a reentry capsule. By adopting a more conventional configuration in which the payload is mounted on the nose of the external tank and the propulsion module at the aft end, you would have the flexibility of using two, four, six or even eight flyback boosters. The only “expendable” components in this STS would be the external fuel tanks which we should be taking all of the way to orbit anyway so that they can be used for station structures or recycled into reaction mass.

James Crawford []

It is one design possibility. I was long a fan of “wings” of some kind, and Max Hunter always liked to have some lift in the reentry vehicle to get cross trajectory capabilities. The problem with wings is they cost like crazy going up, increasing the time of flight, which increases the time that drag operates on the ship, etc. In general the faster you go up the less fuel you need. We have considerable flight data on the Shuttle itself; we need some on entirely different designs now.

Do note that the “bonus” of putting fuel tanks in orbit is smaller than it appears. Fuel tanks in low earth orbit soon orient side-on (one end “down” or pointed at Earth), and the drag goes up, and the tank comes down fairly quickly — and in an unpredictable place. It’s is pretty big, and while 80% of the Earth is water and much of the rest not inhabited or not thickly inhabited, do that enough and you’re sure to hit someone. The remedy to that is to put up two tanks and tether them so that they ride end-on to the direction of traffic, but this means (1) you have to put two tanks into every place you launch one, (2) you need to have someone attach the tethers, and you have the tether as a not negligible dead weight or structure penalty, and (3) at some point you have to go do something with the tanks, which probably aren’t where you want them, because even tethered in pairs they will come down faster than you like. That is a pretty severe operations penalty.

Two stages to orbit, or one stage and a flyable zero which may well be a ring of jet engines, is another possibility: again the operations penalties are not insignificant. The operational penalties are not small: imagine if every time you wanted to fly across the Atlantic, you had to have a second airplane that did nothing but get your plane aloft. It may be required, but it’s not desirable.

So: let me sum it up. We need to build more rocket ships. We need to fly more rocket ships. We need better data. These were conclusions we sent to the President in 1983, and repeated to a different President in 1989. They haven’t changed. We need X programs. Real ones, not corporate welfare programs like the “X”-33. Continued next week.

Jerry, I have one quibble about your formulation of offering prizes to stimulate space capability: At least in the initial prize for reusable launchers, allow for multiple winners, to encourage more entrants. The investors’ perception of risk will lower if the prize for being second by a month is still substantial. Multiple different systems is good; lack of alternatives is a significant (though far from the only) part of our current problems.

Henry Vanderbilt

Agreed. Have second prizes of half the size of the first. For all categories.

The Prizes discussion resumes. See last week.

Mr. Pournelle,

I just read your proposal on offering prizes for companies achieving various stages of space flight and exploration. I think you’re on the right track, but I differ with you on details.

There are a couple of things I don’t like about a big prize for achieving a milestone.

Firstly, what about the guy who comes in second? They spend millions, quite possibly come up with a better solution, and get nothing. “No prizes for second place” is also going to make it more difficult to get investors to come on board: it’s already a risky proposition, now you add the risk of not coming in first. It’s going to mean that you get fewer participants, and once they have a lead established, no one else will even try.

Secondly, it’s my opinion that the “one big prize” system encourages a “we did it once, and we never have to do it again” mentality. It might encourage launch systems that can get there once, but don’t necessarily have good long-term operational characteristics.

I have a counter-proposal that runs on similar lines, but I think addresses some of these issues.

I would treat space launch like the power buy-back laws for electrical utilities: if a company can demonstrate the ability to launch a mission to specified parameters, the government MUST purchase a number of launches from them within a certain time frame.

In slightly more detail:

Using a similar financial setup to your proposal ( I defer to your expertise here), the government sets up basic mission parameters for a couple of useful missions: payload X to orbit Y for Z dollars. One might be a satellite/science payload launch, one a delivery to ISS, one a heavy lifter.

If a company can demonstrate launch capability by putting a dummy payload in orbit on their buck (aluminum girders, say), the government is required to buy 10 launches from them at the specified price within the next 5 years. The company eats their development costs, and any cost overruns.

At the end of it, you wind up with companies that have demonstrated working launch systems, and demonstrated income. They can now attract investors.

I would not specify SSTO, takeoff/landing mode, fuel or most other technical details: you want them to try every approach.

If the program is wildly successful, it could go over your 2 billion dollar mark in costs, but you would get at least 4 working launch systems out of it, and 40 launches.

The major flaws I see are:

Too much success could get expensive. Not really a bad problem, but a problem. Possibly put some kind of cut-off on each launch category: first 5, within 10 years, etc.

Companies will all tend to try for the mission with the easiest launch parameters first. However, after 10 launches, they have to go to a different mission profile to get more money from the government.

Towards the end of the program, it may be harder for companies to attract investors because the launch market is swamped with launches the government is auctioning off. Again a problem of success, and a short-term one.

I would be interested in your thoughts on my idea.

Lastly, back in 1989, you were the guest of honor at the Hostigos science fiction convention in State College, PA. On Friday night, I came up to you in the con suite and asked you to sign my copy of Legacy of Heorot, which you did even though it was outside the regular book signing hours. (I had to leave early the next morning to go back to work in Philadelphia.) I just wanted to say thank you, it was gracious of you and meant a lot to me at the time.


Jon Acheson

Insisting on perfection generally gets nothing. A number of us have tried to get modifications of the Space Services and Procurements acts to require purchase of launch services. I even had one in which the government would simply pay for the verified launch of water or sand into orbit: developing the launch capability would be worth it. Nothing came of any of that.

The value of prizes is that there is no cost until the task is accomplished, and the total cost is limited and known. If you insist on “being fair” to all the losers in a competition then you are in essences saying don’t do anything.

It would take Congress about 6 hours to pass the prize legislation I described. If that cause no results, well, so be it; but it might in fact get things going. There may be better ways, but I have seen no reason not to try the prizes in addition to anything else.


Returning to the SSTO debate.

Dr. Pournelle, I began this note several weeks ago, never guessing that it would be relevant so soon. It is interesting how many similar thoughts have already been submitted, but I think this has a slightly different slant.

Regards, Robert Mitchell Research Fellow Landmark Graphics

Cheap Space Transportation

I read your discussion of cheap space transport with a great deal of interest. Clearly, there is a market for cheaper satellite delivery to orbit. If you could deliver roughly the same or better reliability as current launch systems, but at, say, a 20% reduction in cost, the customers would stand in line to buy. I would expect this level of cost reduction to be easily achievable, since no launch system has ever been designed with minimum cost to orbit as the primary design criterion. I realize you want much more than this, but the point I’m trying to make is that there is a realistic business argument to be made. I’m sure D. D. Harriman would understand. Without a solid business argument, there is no option but government funding.

While I am sympathetic to your arguments, let me play devil’s advocate with some of the details.

Why do we want single stage to orbit (SSTO) technology? The benefits I can think of are:

1. No logistics problem of assembling and reassembling multi-stage vehicles, assuming all parts are recoverable and reusable.

2. Multi-stage design has numerous problems of design and integration that could be avoided by SSTO design.

The major drawback to SSTO is that it must be a very high performance design. This suggests that it will be expensive to build, and likely expensive to maintain. Engine life, if not vehicle life, may be short because of high performance – low weight design. As you observed, payload is marginal, so everything must be designed to the limit of safe design, or beyond. It seems to me, “design to the limit” caused the failure of the X-33 program. The liquid hydrogen tank was being fabricated from composite materials to save the last ounce of weight, and an effective design could not be produced on budget. Lastly, I don’t think that building sub-orbital models and then “tinkering” them to orbital capacity is a viable strategy. At this level of design sophistication, drilling holes to save weight is just not an option.

By focusing on SSTO, we have lost sight of our goal! The goal is to minimize the cost of delivering things to low Earth orbit. To achieve this goal we need:

1. Low vehicle cost. We want to buy a lot of them and we want economies of scale.

2. Low maintenance cost.

3. High reliability.

4. Recoverable and reusable if the economics dictate.

5. Conservative design.

6. Low cost to launch.

You will be hard pressed to assert that SSTO satisfies any of the above criteria! (The current space shuttle doesn’t meet any of these criteria either! For example, the solid rocket boosters are recovered and refurbished without regard to the cost. The design criterion was that they be reusable, period. ) Note that high performance is not one of the design criteria. High performance is costly in every aspect of the design, and will likely fail every one of my design goals. Minimum fuel usage is probably not a design goal, either. The design must meet the performance requirements with some margin for error. Any improvements over designed efficiency will be considered good fortune!

My guess for a suitable design would be a two stage to orbit vehicle, with the first stage booster to be a very simple design – pressure fed engines using RP-1 and liquid oxygen. The orbital stage will be designed to accept 2, 3, 4, or 6 first stage boosters to allow maximum load flexibility. We might fly these stage 1 boosters to a soft landing a la DCX, then barge them back to the launch site. The orbital stage will be very DCX in design, but of lesser base performance dictated by overall system cost. This stage will likely be reusable, so it will be designed with low cost maintenance considerations.

Another stage 1 option might be “stage trees”, to borrow a term. I wonder how cheap we could make reliable, single use solid fuel boosters? Especially, if we made a lot of them.

I personally doubt that NASA would allow anyone to build and launch such a vehicle from the US. Perhaps Japan might be interested – I’m surprised they haven’t done this already.

In the following I have taken an angrier tone than this letter deserves, but I have grown weary of saying all this over and over. If people want to address the subject, surely it is not unreasonable to ask that I be challenged on what I have said and proposed, not on some myths? It isn’t as if the papers weren’t available, many of them RIGHT HERE.

I presume your letter covers the subject? It contains a mass of bad assumptions, none made explicit, while what is made explicit is delivered as a revelation when in fact every bit of that was considered before the Council recommended SSX to the National Space Council. The problem with this analysis is that it assumes that the Council consists of idiots. In fact, we had the very people who produced the arguments against SSTO that kept it in limbo for so very long, and who had figured out what was flawed in their original thinking.

Given that nearly everyone, including me, failed to see all this for 20 years or so, I suppose it’s not surprising that others still don’t get it; but I do wonder that few have bothered to read the original Council reports and the arguments we made then, so that I have to do it all over again. In future, before writing me on this, at least read what I have written. You can start with papers available right here on this web site. One was my Congressional testimony about SSTO and SSX. It was under oath: I may be wrong, but I certainly wasn’t making things up. At least read that.

You might also want to see just who this Council is, and some of what it said. That’s here too.

Now to take a few obvious points.

  1. Spacecraft are expensive. At the moment they are made extremely expensive by the high costs of launch: they have to last a long time. They are generally obsolete about the time they get up given new technology. But even cheap spacecraft are expensive, and if they are lost on takeoff this is A Bad Thing.
  2. It is desirable to have SAVABLE space craft: ships that on launch can be saved if one of the more common problems develops; saved before they get to orbit or even to re-entry altitudes. The first criterion of SSX was SAVABLE.
  3. We don’t want to “buy a lot of rockets” to get costs down. That may be the right way to do it, but rocket ships are expensive, and even in mass produced quantities the ammunition concept concedes some fairly heavy costs. The goal is to get costs down: not to buy a lot of rockets. As to “expensive” vs. “cheap” spacecraft, the same analysis applies as to airplanes. Each copy of a 747 is a very expensive proposition; but if that plane flies many times the cost per flight is minimized. What we want to look at is the cost of getting stuff into orbit, and those costs need to include operations costs.
  4. Trying to minimize the cost per launch vehicle is a classic case of suboptimization, of solving for the wrong variable, and the fact that this is a very common mistake doesn’t excuse it.
  5. We learned nothing from “X”-33 and no one expected to learn anything from it. Why you wish to beat me up about a project I opposed and about which I forecast disaster is beyond me. All “X”-33 proved is that Lockheed was able to influence decisions a lot better than I or my Council could. That probably wouldn’t have happened in Reagan’s day, but Bush First got rid of every Reagan person in the Administration as soon as possible, leaving us with no one to talk to but Mr. Quayle. Quayle was in fact able to get DC/X funded, but not to get enough money for SSX.
  6. X”-33 wasn’t intended to be SAVABLE, and thus threw away a major cost benefit of the kind of spacecraft we advocated.
  7. The major advantage of the SSX approach to spacecraft design was that it could be incrementally tested. That is, like DC/X it could be flown to low altitudes and landed. Then progressively higher altitudes and speed regimes. We would be developing flight data. We would be learning about operations costs, as well as about performance requirements.
  8. The assumption that SSX design was to be performance driven is flat wrong and demonstrates unfamiliarity with the concept as proposed and advocated.
  9. One of the major features of the SSX approach to space ship design was that this was to be an operations driven design. By concentrating on operational factors we would learn what performance we required. If the performance proved to be beyond our capability within permissible costs we would know that reasonably early. The data developed would be useful in determining what the new approach should be.
  10. By having an X ship that could be incrementally tested and operations driven, we could determine what kind of performance improvements we could make through incremental changes in structure design. Most early models of high performance craft are over-designed. By flight testing you see what parts are more than strong enough, and lighten the structure. This is what Hunter used to call “nickel and dime” improvements, and they can result in very significant performance improvements without risks.

As to your breathless revelation that Shuttle doesn’t do this, you may well have got some of that observation from me, and almost certainly you achieved that revelation from people who were part of the Council. Did you think we were unaware of it?

Accusing me of wanting a new supershuttle is absurd given all I have written on the subject, and my apologies if this seems a bit curt, but I am weary of people using that argument. The Shuttle is not reusable, it is refurbishable, and Columbia’s 28 flights over its lifetime are absurd compared to, say, the lifetime flights of an early 707.

Your guesses on what might be the final ship may well be correct, but are based on guesswork and theory. The SSX approach was intended to find out by flying hardware. None of us were locked on to Single Stage to Orbit: but of course it’s convenient to label us with that and then spend time talking as if all reusable ships have to be SSTO and have to have super high performance.

Our approach was a series of experimental programs to develop ships that would be:

  1. Savable
  2. Reusable
  3. Higher
  4. Faster
  5. Cheaper

The notion was to develop those ships through incremental testing.

All that was in the reports. Continued later.


At this point I urge you to go read the material in Mail, including spread sheets and the like. It’s well worth the effort, but it’s a bit long for inclusion here.

Then partly in reply to that, Henry Vanderbilt sent:

And Henry Vanderbilt on SSTO and unexamined assumptions:

Jerry, I can appreciate the irritation you must feel over your anonymous mainstream aerospace correspondent; he is to a considerable extent a prisoner of unexamined assumptions, and he seems to be taking you (us) to task for failing to treat these assumptions as laws of physics.

To sum up, it’s not news that an SSTO requires that *everything* aside from propellant – structure, payload, engines, orbital maneuvering reserves, reentry and landing provisions, the pilot’s lunch – fit into something ranging from roughly one-eighth to one-sixteenth of the gross liftoff mass, depending on propellant choice and engine performance. All else, 88% to 94% of liftoff mass, must be propellant. Payload, if any, must fit into the remaining 6% to 12% of GLOW. [And in early models that is likely to be around 1% of GLOW. JEP]

Nobody I know says that engineering such a system to carry a useful payload with a useful vehicle life in a practical vehicle size at an affordable cost is easy. Indeed, NASA has provided us with multiple demonstrations that under its habitual space-launch system development model (contractor-in-every-district mass-assault engineering with a major extraneous-agenda burden) weights and costs will reliably grow to impractical levels, whether the goal is SSTO or not.

Your correspondent bases his modeling on assumptions derived from historical experience with this system, produces a spreadsheet that shows impractical weights and costs, and asserts this proves SSTO impractical.

In fact, what he proves is something we knew back in 1988 when we steered what became DC-X away from NASA: SSTO (indeed, cheap space transportation in general) is impractical *within the existing NASA-Industrial complex*.

I can’t blame a fish for not realizing there are environments other than the water it swims in, but your correspondent really ought to be able to think things through a bit further than the average fish. Other better space-launch development environments are possible. Easy to achieve, no, no more than radically-cheaper reusable space launch systems are easy to engineer. But neither is impossible. And (plug time) anyone who wants to learn more about the possibilities should come to our next conference, April 24-26 in Scottsdale AZ. ( )

Henry Vanderbilt Executive Director, Space Access Society

Precisely. It’s not so much irritation as dismay: I feel the way Max Hunter must have felt when Arthur Clarke began his campaign against SDI with incorrect assumptions. I think you were not there the day that Arthur came into a council meeting to see Max ready to oppose him, and exclaimed “But Max, I learned everything I know about celestial mechanics from you!” Whereupon Max said, gently, “I didn’t teach you enough, Arthur.”

That’s how I feel: I didn’t teach enough in Step Farther OUT and Strategy of Technology.

Or, I have become entirely senile; but if so, then all the other signers of the 1988 SSX report including Max Hunter and Gordon Woodcock and Chuck Lindley and the rest had become senile too…

Our briefing to Quayle had a chart on potential problems. The first item on that chart was “Capture by NASA.” Had NASA been put in charge of DC/X it would not have been built, nor ever flown. When NASA did get control of SSTO development the result was X-33. NASA simply cannot do X projects. It has forgotten how, or even what X Projects are.

NASA can do, and sometimes does, space science. Not space technology development. Space science. But the glory days of expanding space technology are gone, and NASA will never regain them.

I have recently been dismayed to learn that we probably have no aerospace team left in the US that would be capable of building a 600,000 GLOW multi-engine savable SSX for flight testing. No one. If we wish to revive the X projects we will have to start smaller and build new teams that relearn lessons we once knew.

I hate that, and I would love to be proven wrong; but my advisors estimate that a more modest system with the goal of savable, reusable, and capable of Mach 12 for 1 minute as a Thermal Protection System testbed would be about right now; useful, within our capabilities, and leading to teams able to do more ambitious projects.

I would still like to see a 600,000 pound GLOW SSX, but I would be satisfied with the Mach 12 savable and reusable TPS test system as a preliminary step. But we better get to that or we may lose that capability too.

None of this is expensive compared to the cost of a war; the whole thing would cost less than was wasted on X-33. It is cheap compared with continued reliance on Shuttle.

“did anyone approach Douglas with this proposal?”

Having worked for McDonnell Douglas for 13 years during which I watched their airliner business go from 48% of the market to 0% (bought out by Boeing), I couldn’t let this comment go by without comment.

The whole reason there is no longer a company called McDonnell Douglas is that our management completely lacked any tolerance whatsoever for risk. We built excellent vehicles, but management turned down each and every opportunity in the late 80s and throughout the 90s to drive forward into the future. This, in the aerospace business, is pure death.

Sure, there were lots of other problems with the company but it was risk-aversion that guaranteed that McD-D would eventually die in its sleep.

Owen Strawn

Indeed. Thanks.


Things sort of died away after that, at least for a while, mostly overwhelmed by the war.

Then we got an inquiry about Prizes again. (June 11, 2003)

Hey Jerry,

I like your books, and I from reading both them and your site, it seems I agree with most of your politics. But (if memory serves) you have advocated a $1 Billion government funded incentive for the first private company to get to space. Why do we need government to get involved? Free enterprise is already doing much the same thing with the 10 million X prize. Why do we want the government to get involved and take credit for something that would have happened anyway, and that the existance of a government space program may very well have delayed? I read Diamondis wanted to get in space with NASA, decided their was not much of a chance of that, and got the X prize together. Why do we want a government X prize to compete with any future private prizes? I understand government having military space projects, but I don’t know that the government should be involved with civilian space transport. Private groups would not be able to leap straight to the moon, that is true; they would have to jump from one profitable step to another. They would have to build the infastructure gradually, but if private funds can get us to suborbital flight, (and is looks like this is going to happen early next year), why not orbital flight and beyond? The father private enterprize gets in space the more funds will be available to it. Why get the government involved? Sorry if I misstated or misremembered any of your opinions. I didn’t see the particular place on your site where you advocated a billion dollar incentive. I seem to remember you advocated something similar in one of your non fiction books.


Ian Perry.

The X Prize is $10 million, and hardly an incentive to get to orbit. Rutan’s efforts will not lead to orbit: there is no path from what he is doing with hybrid engines to real orbital flight. Hybrid engines are at best (assuming they can be made to work reliably) utility engines for small delta-vee.

If you can raise a billion dollar prize for a reusable manned orbital ship — if the Gates Foundation wants to offer one — then you will see efforts at building them. The X Prize doesn’t lead to orbit.

Meanwhile, there are more national defense needs for reaching orbit than there are commercial; if it were not so we would already have private orbital development a lot further along than it is.

For 40 years I have been trying to get both government and private industry to develop means for low cost manned access to space. With private industry it always goes this way: you convince people there are technical risks but we can solve them.

They then ask “And what is your business plan? We know the market for communications satellites, but that can be done unmanned. Why do we need on-orbit construction capability? What can people do for money in space? What is the market?”

To which the answer is, “If you build it, they will come,” and you wave your arms about a lot, and talk about tourism and such like, and the chap quite properly says, “Hmm. There are both technical risks and market risks, why don’t I invest my billion in an oil company?”

The fact that I believe there will develop markets using large manned space facilities doesn’t mean I can make arguments that survive due diligence inquiries. On the other hand I have no trouble at all showing why easy manned space access and on-orbit assembly capability has profound military implications.

We could have developed all this in the 60’s and 70’s, but we went another path. Arthur Kantrowitz tried to convince Kennedy’s people that the best way to the Moon was through development of manned space access, a von Braun manned space station, and on to the Moon in a logical way that left developed space assets. That didn’t work, because Johnson’s support of the Moon Mission was contingent on spending money in the South: the real objective was the reindustrialization of the South. The Moon mission itself was a stunt.

Developing space assets is not a stunt, and please do not send me mail citing all the various potential industrial uses of space. I wrote many of them, and G. Harry Stine wrote most the rest, Harry getting much of his data from the meetings I chaired (and don’t take this as any kind of resentment against Harry: we divided the labor and he did the popularizations, and I miss him). Industrial potential is not a market plan. I know. Boy do I know.

Prizes are a way for government to reap the benefits of developing space capabilities without the government dominating everything through the creation of another monster like NASA. Prizes cost nothing until the feat is accomplished.

Editors’ Note: Please leave your comments and thoughts on this subject below. Politeness is a virtue that should be followed as you enter your comments.

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