The last Space Shuttle launch is scheduled to happen within a year. I have never been a fan of the Space Shuttle so it couldn't happen too soon for me. What follows is a quick history of rocketry in general and the Shuttle in particular with an admittedly U.S. bias.
The rocket was invented by the Chinese several hundred years ago. Various efforts to transform the rocket from a novelty into a useful and practical device, e.g. for use in warfare, were generally unsuccessful until recently. That all changed with the work of Robert Goddard and a small number of associates operating on a shoestring budget. Goddard developed the scientific foundations of rocketry in the early part of the twentieth century. He launched a number of rockets, primarily in the 1930's, to turn his theoretical work into practical devices. Unfortunately, the only ones paying attention were a bunch of Nazi Scientists, most notably Werner von Braun.
Von Braun and his team refined Goddard's work and turned it into a practical military device, the V-2 rocket used against the British in World War II. The V-2 would have been more successful except for a British intelligence effort called "Double Cross". Double Cross convinced the Nazis that they were scoring direct hits in downtown London when, in fact, the rockets were actually landing in the suburbs to the east. In spite of this, the V-2 was a clear demonstration that rockets could actually be put to practical use. And the obvious practical use was to carry nuclear weapons.
As a result of this several countries, most notably the U.S. and the U.S.S.R. (Russia), launched efforts to build large rockets for military and other purposes. The U.S. put its efforts on a slower path because they had airplanes (e.g. B-52 bomber) that could be used to effectively deliver nuclear weapons. The USSR, without this option, put more effort into their program with the result that the USSR launched the first Satellite, Sputnik, in 1957. The USSR was also behind in efforts to miniaturize nuclear weapons so they aimed for rockets with heavier "lift" capacity than comparable early US efforts. This resulted in a number of other USSR space "firsts" like the first man in space (Uri Gagarin). The USSR reaped a PR bonanza for its efforts. Understanding that the USSR would continue to rack up "firsts" for at least a couple of more years, President Kennedy set a US goal of "landing a man on the moon and returning him safely" in a speech on May 25, 1961. The goal would take about ten years, giving the US a chance to catch up and go ahead in the "space race", an important aspect of the "cold war".
NASA configured the Mercury (one man flights), Gemini (two man flights), and Apollo (three man flights) programs into a path to achieve the "man on the moon" goal. Apollo resulted in the first manned moon landing on July 20, 1969. The "man on the moon" stunt was essentially a PR stunt, in terms of reasons for the political backing necessary to find the money to make it happen. And by July of 1969, when the landing happened, Nixon had taken over from Kennedy and then Johnson as US President. Nixon, unlike his two Democratic predecessors, was not a fan of the space program. But it was immensely popular so he had to come up with a follow on to Apollo. The obvious choice was a "man on Mars" program but this was way too expensive and likely not feasible. The fall back option was a permanent moon base. Again this was fantastically expensive but probably barely feasible. It was certainly too expensive for Nixon's tastes. So the next fallback option was a space station. This lacked "sex appeal", as had the moon base, but even this limited objective was deemed too expensive. So the Nixon administration proposal was the Space Shuttle. The theory was that whatever follow on manned space project was selected, the Space Shuttle would be useful.
So the Space Shuttle was chosen because it was the cheapest alternative. And one justification was to make spaceflight cheaper. But more justification was needed for public consumption. So the other official objective was to make spaceflight ecologically friendly. Up to this time all rockets were "one off" proposals that spewed out vast amounts of pollution. This seemed wasteful. So how about creating a reusable space vehicle? It would save on resources because it would not have to be built over from scratch. And this would help make it cheaper to operate. That's what the Nixon administration came up with.
The concept for the base vehicle was a "space capable" DC-9 (commercial airplane). But there was not enough room inside for all the rocket fuel. So a cheesy external tank was added to hold the fuel. Well, this made the whole thing less efficient so two cheap "strap on" solid fuel external rockets were added. That gave the whole vehicle enough power to get off the ground. And the strap on rockets were supposed to be reusable too. The result was an abortion. The "engineering" that went into the basic design was awful. But the engineering to actually make the abortion work was awe inspiring.
I can not overemphasize the amount of genius engineering that was necessary to make the Shuttle work at all. But the result of slapping all this together was that the Shuttle failed to achieve any of its design objectives. It quickly went massively over budget. It went over budget both with respect to time (it was years late) and cost (its actual cost was several times the original estimate). At one point the cost problem got so bad that NASA promised that operationally it would be so cheap that the US no longer needed traditional ELV (Expendable Launch Vehicle) rockets. This allowed NASA to steal the money that would otherwise have been used to purchase them to plug into the Shuttle budget deficit.
Eventually construction was completed and the Shuttle went into service. But it turned you that the nightmare was just beginning. The Shuttle was NOT economical to operate. It turns out that spaceflight is very hard on hardware. So instead of an airplane like (roll it in, gas it up, clean the johns, replenish the in flight meals and booze, and roll it out) process after each flight the Shuttle needed extensive maintenance. So it couldn't be turned around quickly. It was not just a matter of paying for another batch of fuel. A lot of parts need to be replaced or refurbished, and all this required a large, well trained and therefore expensive, support operation. Shuttles were way more expensive to fly than the ELV rockets they competed with. So the flight rate has never even been half of what was initially predicted. And they are down frequently for some major fix so they are not dependable. And they are bloody expensive to operate when they are working. A typical flight cost between $600 million and $1 billion dollars. You can buy several ELV launches of even the largest expendable rockets like the Delta IV, Atlas V, or Ariane 5 for the price of one Shuttle launch.
And they are not safe. We have had two tragedies. The first one was caused by the famous "O-ring" problem with the strap on external rockets. This problem was not caused by any inherent problem with the Shuttle. Rather the problem was a direct result of NASA trying to keep costs as low as possible. Everything about the Shuttle was way more expensive than it was supposed to be. So NASA only funded the "necessary" and not the "nice to do but not absolutely necessary". The O-ring problem was only a "potential" problem and not an "actual" problem. Until, of course, the O-ring problem eventually became an actual problem with disastrous results.
The second tragedy, however was a direct result of the design. The Shuttle uses liquid Hydrogen and Oxygen for fuel. Both of these are very cold. So insulation is critical. But it must be thin and light. Insulation is sprayed on various things. Its primary job is to insulate so its strength is minimal. The Shuttle itself is also built as flimsily as possible to save weight. Now in a standard "stack of tubes" rocket design, if something falls off it tends to drift away from the vehicle slightly and, therefore, not hit it. But the Shuttle has all these things that are beside each other so when an object drifts slightly away from one part it can run not into empty air but into another part of the Shuttle. And, since the Shuttle is as flimsy as possible, when it hits, it can do a lot of damage, even if "it" is a light fluffy piece of foam. And that's what happened. A piece of foam broke off, hit another part of the Shuttle, and knocked a big hole in it.
Besides these two problems that resulted in tragedies the Shuttle has had a large number of less serious problems. These have led merely to costly (both in time and in money) delays. An obvious solution to the "problem" of the Shuttle is to replace it with a better design. And this NASA has tried to do in the last few years. President George W. Bush initiated the "Orion" program to develop two more traditional vehicles to replace the Shuttle. But Orion has run into schedule and budget problems too. An obvious alternative is to "man rate" one or both of the Delta IV/Atlas V. This seems the most sensible approach to me but has not been adopted for political reasons. And even man rating the Delta IV/Atlas V would run into a lot of money. What's going on here?
It turns out that Goddard did his work too well. For instance, he figured out that Hydrogen/Oxygen is the best fuel for a "chemical" rocket. You have to go with some kind of Science Fiction approach that does not depend on chemicals for fuel to do better. He also patented the multi-stage rocket concept in 1915. There was a lot of tough engineering work necessary to go from his primitive devices of the '30s to the V-2 of the '40s to the Sputnik of the '50s to the Saturn 5 of the '60s. And, in my opinion, the Shuttle of the '70s is no improvement on the Saturn 5 of the '60s. But the only fundamental advance over Goddard was the adoption of ceramics for insulation. The other advances were important and difficult to achieve but they were not fundamental. And there have been no fundamental advances since. The Orion rocket designs were based on modifications of components from the Saturn 5 or the Space Shuttle. There was no new breakthrough technology or even design. The design was a classic "stack of tubes".
We now have massive computer resources available to assist in the design. We have advances in materials. The metals available now are stronger and more heat resistant than the metals used in the Saturn 5 but not to the degree that results in a fundamental difference. Likewise, the ceramics available now are better but not to a fundamental degree. And there is no new design idea that makes a fundamental difference. So we can do the job better than we could then but not a lot better. And that means that modern rocket design is better but not a lot better than what was available in the '60s. And, most importantly, rocketry is not a lot cheaper.
The latest idea is to privatize the whole endeavour. The idea is that NASA is stupid and inefficient. There is a case to be made that NASA is stupid. But most of the stupidity can be traced to two factors. The first is politics. NASA must site facilities and do work in many locations in order to spread the money around for political reasons. This is a stupidity forced on NASA by external forces. The second source of NASA stupidity is budgeting. NASA has repeatedly done stupid things because it has not had the money to do things right in the first place. The first Shuttle disaster is a classic example of this. But NASA has been running the manned space program on the cheap, as in too cheap, since about 1970. The cost of a PR spectacular is just too high. No one will pay it. And there is just no "hard nosed business" reason for the manned space program. There never has been one.
We will see if privatization is effective is solving NASA's twin "stupid" problems. I don't think it will. Privatization is a very good cover for pretending that space spectaculars can be had "on the cheap" so I expect that the pressure to drive NASA's manned space budget even lower will increase as the shift to privatization progresses. If privatization is substantially cheaper then the budget will go down enough to more than compensate for any increased efficiency. Now I think there is room for cost saving. A private operation that does not need to spread the work around to the districts of powerful members of congress can save some money. And theoretically the private sector can squeeze out "CYA" costs. But the private sector also wants to make a fat profit (NASA makes none) and pay its senior executives fat salaries and bonuses (a lot more than current NASA senior managers are making). So what's the balance point? I think privatization can possibly save 10-20%. And 10-20% is not enough to make a big difference. I think privatization will ultimately be used to kill off the manned space program.
People don't understand just how expensive the manned space program is. The US has sunk over $100 billion into the International Space Station (ISS). We have gotten some PR benefit. But due to budget problems, almost no scientific work has been done on the ISS. One justification for the Shuttle has been that it could be used for scientific purposes. But almost no scientific work has been done with the Shuttle because science has always been cut out of the program to solve budgetary problems. So the only payoff for the Shuttle has been PR. Like the ISS, there has been only a small amount of PR benefit from the Shuttle. And that has to be balanced against the fantastically high cost.
The cost of a single Shuttle launch is about the same as the New Horizons mission to Pluto. New Horizons will cost about $650 billion over the lifetime of the mission (2001 - 2015). It will do the first flyby of a "dwarf planet". We know almost nothing about dwarf planets in general and Pluto in particular. The scientific payoff will be tremendous. And, given the place Pluto plays in culture (think the Disney cartoon dog, for instance), it will also generate a large amount of PR benefit. Another unmanned program, the Spirit/Opportunity mission to Mars, cost far less than a single Shuttle launch. But if you say "Spirit and Opportunity" to a significant segment of the public they will recognize them as Mars rovers and have a very positive opinion of them. So the "Spirit/Opportunity" mission is another unmanned mission with a large scientific and a large PR payoff.
Contrast this with the manned space program. Most of the public no longer follow Shuttle launches. Among those who do, a significant segment is interested in the "car crash" aspect (is something going to go horribly wrong). Interest in the ISS is also at an all time low. I am interested in these kinds of things and I can't tell you who is currently aboard or what they are doing. So the PR payoff has been low for the manned space program for a long time now. People are generally in favor of a manned space program, Science Fiction movies are popular, but that general approval does not translate into any kind of political will. The only people who really care are the contractors. There principle interest is in a paycheck. People in congress who represent space heavy districts care. But what they care about is the payrolls and political contributions, not what the manned space program actually achieves.
Nearly all of the scientific benefit from the space program and nearly all of the PR benefit of the space program have come from the unmanned side, especially in the last 20 - 30 years. Given the lower cost of unmanned missions compared to manned missions, and given the much higher scientific payoff of unmanned missions compared to manned missions, and given even the higher PR payoff of unmanned missions compared to manned missions, I expect the payoff to continue to favor unmanned missions over manned missions by a large margin.
And given the high cost and meager returns both in science and PR, why do we even continue to have a manned program? I think it is because no politician wants to be known as the one who killed off the manned space program. But privatization provides an out. There has been some squawking about privatization but not enough to seriously affect its trajectory. Once NASA has handed over responsibility for manned space programs to private industry it becomes possible to do a "death by a thousand cuts". You just keep cutting the money you hand over to private contractors. When a specific project is killed it is due to "private sector incompetence or greed" rather than some bad thing a politician did. So the manned space program dies but no politician is arrested (loses an election) for the crime of killing the manned space program.
No comments:
Post a Comment