Thursday, November 20, 2008

Constellation



Now for a serious post about outer space...

Constellation is the name of NASA's program to return to the moon, and possibly continue on to Mars, or even maybe other destinations in the solar system. It consists of two major components, the Ares booster system and the Orion crew vehicle.

The Ares system consists of two major components, the Ares I for launching the Orion crew vehicle into orbit, and the Ares V heavy-lift booster for launching major Constellation components into low earth orbit for on-orbit assembly and rendezvous with the Orion for subsequent deep space exploration.

The first thing that strikes almost anyone about the Constellation program is its uncanny resemblance to Apollo. The Ares I and Ares V boosters seem very similar in performance, size, and function to the Saturn Ib and Saturn V. (Perhaps they will eventually rename it the Ares Ib.) It seems almost impossibly retro.

NASA clearly recognizes the obvious similarity, and refers to Apollo five times on the Orion web page. They point out that Orion is much more advanced technology, despite the outward similarity, and has 2 1/2 times the internal volume of the Apollo command module, and referred to Constellation as "Apollo on Steroids" at the introductory press conference.

The Orion "crew exploration vehicle" (CEV) will carry 6 astronauts to low earth orbit, or four to the moon, will land ashore instead of at sea, and be reusable. It is NASA's final format to replace the space shuttle, which is a very disappointing decision.

The reason that the US space program ended up being based on missiles (specifically on the Nazi V2) is because the people at NASA who developed the program were Nazi rocket scientists. At the same time, the Air Force (with some NASA cooperation) was developing aerodynamic spacecraft - vehicles capable of using lift, instead of pure thrust, to escape the earth's atmosphere.

Although there were some additional technical obstacles with true "flying" spacecraft (mainly associated with the heat shielding), the potential advantages were substantial. There's a reason that United and Southwest fly airplanes and not rockets - they are a lot more efficient. You can lift a lot more payload with a lot less fuel than you can with a rocket.

The Air Force was already, by the early 1960s, flying to the edge of space in an aircraft, the rocket powered X-15. There was a huge and impassioned debate about the best strategy to launch payloads into space, via aircraft or rockets, with NASA and the Army on the side of rockets and the Air Force and much of the aerospace industry favoring aircraft. Ultimately NASA won out because of the enormous influence and persuasive abilities of Werner von Braun. Ironically, von Braun had proposed and advocated aerodynamic space vehicles at various times in his career, but had been employed by the Army's Ballistic Missile Agency (which became NASA's Marshall Space Flight Center) since WWII and was parochially aligned with the Army and missiles.

The Air Force had a "mini space shuttle" design by the late 1950s - the X-20 Dyna-Soar, but that program was scuttled by the political efforts of NASA and Werner von Braun, who claimed it would compete with and reduce resources available to the Apollo lunar program.

This was all very unfortunate. Von Braun originally proposed the moon mission be stages as an Earth Orbit Rendezvous (EOR), using re-usable boosters and spacecraft to deliver large quantities of material and components for a very substantial moon expedition. That model - which has been revived for Constellation - would have been very well served by simple, rugged, reusable aerodynamic orbital vehicles like the Dyna-Soar.

Officially, Dyna-Soar was killed by Secretary of Defense Robert McNamara in 1963 because he said "there was no significant advantage in controlled re-entry", the publicly-stated main difference between Dyna-Soar and the Gemini Program. But a tremendous amount of the real history of the Dyna-Soar is shrouded in secrecy.

Dyna-Soar was originally intended to serve as a global exo-atmosperic, hypersonic weapons platform, similar to a Fractional Orbital Bombardment System (FOBS). It was a direct decendent of the Eugene Sanger's proposed Silbervogel, also known as Hitler's Amerika Bomber. Eugen Sanger, of course, was a colleague and competitor of Werner von Braun in Nazi Germany. The Amerika Bomber was the Nazi's planned unstoppable delivery platform for their nuclear bomb. The Silbervogel, which was designed in 1934 but never flew, looked a whole lot like an X-15. I think in my old blog I did a post comparing the designs of Sanger, the Horten brothers, and others in Germany in the early 1930s with the most advanced aircraft in the United States at the time.

A summary:

Germany, 1934



United States, 1934:



Clearly there were very different things going on there.

What was going on in the early 1960's, however, was very heavily influenced by the cold war and the desire to contain the Soviet Union. Anything that could potentially prove to be an assymetrical advantage, such as a fractional orbital bombardment system or orbital reconnaissance systems, was very heavily classified.

The apparent promise of aerodynamic space vehicles, however - their ability to maneuver much more radically in orbit than NASA's capsules, their re-usability, and their ability to fly to any point on the earth and land in a very short time - made their seeming abandonment in the early 1960s, after the spectacular success of the X-15, very puzzling indeed.

While the publicly known history indicates it was NASA and von Braun's political persuasion that shifted the emphasis to rockets and away from aircraft, there have long been rumors that the space-planes simply "went undercover".

Those long-circulating rumors were ratified in 2006 by Aviation Week and Space Technology magazine, with a cover story claiming the existance of a highly covert space plane program, derived from the Dyna-Soar and known as "Blackstar". According to "Aviation Leak", as it is often known, the "Blackstar" program was a two-stage-to-orbit binary system based on not only the Dyna-Soar but also the cancelled XB-70 "Valkyrie" supersonic bomber. The Valkyrie served as the first-stage "mother ship" which lifted the orbital vehicle to around 100,000 feet for launch into space. Such a system makes a lot of sense as a much more efficient way to achieve orbit, in comparison to a multi-stage rocket.

The theory goes that the Air Force has had a space-plane program for many years, possibly since the mid-1980s, and many of the publicly-announced space plane development efforts since then, such as the X-30 National Aerospace Plane, were derived from, or used as cover for, the secret spaceships.

But if any of this is true, it's a really good secret. While there is plenty of evidence the Department of Defense spent billions on the 80s and 90s on very highly classified projects, there's no good evidence they bought any manned spacecraft with all that money. There is also solid evidence that the Air Force has flown something that goes very high and very fast since the retirement of the SR-71, but again there's nothing to say with any reliability its a space plane. An unmanned hypersonic demonstrator prototype may be a more likely scenario.

It should be remembered that there were several aerodynamic spacecraft proposed to replace the Space Shuttle. Lockheed's most recent proposal in 2006 looked pretty much exactly like the X-20X Dyna-Soar III.

But once again, after many years of signaling that the Space Shuttle would be replaced with something truly versatile and innovative, NASA decided to go back to the 1950s with Werner von Braun's rocket-and-capsule format.

What the heck? After all the work done on aerodynamic space vehicles, hypersonic pulse-detonation-wave and aerospike engines, advanced composite heat-dispersing materials, and digital flight controls, we're going to chunk it all and build "Apollo on steroids".

Is there something I'm missing here? The Apollo redux will use von Braun's original Earth Orbit Rendezvous, which is tailor-made for a rapid-turnaround, highly efficient aerodynamic lift platform. What you need to do is make a lot of trips to orbit to assemble the parts for your deep-space exploration vehicle, which could be boosted in pieces on existing launchers. You create a new "space shipyard" to exist as the permanent launching point for further exploration, which you can get to easily by launching an aerodynamic vehicle from a two-stage-to-orbit system like the rumored "Blackstar", or cancelled Dyna-Soar. Why do you want a new Apollo system for that requirement? It just doesn't seem to make a lot of sense.

One of the angles that might explain it is the desire for safety. The loss of Columbia and Challenger revealed just how dangerous the aerodynamic Space Shuttle is, while the Russians early-60s vintage Soyuz capsules are tried and true. In many ways, the Soyuz system is much superior to either Apollo or the Space Shuttle, and certainly it's proved its worth. The first Soyuz flew in 1966, and the United States will rely on Soyuz for access to the International Space Station in between the retirement of the Space Shuttle in 2010 and the first flight of Orion, which is hoped for 2014, but given the US Government's record in recent years with this sort of thing, may be fantastically optimistic.

Regardless of the format or direction NASA wishes to take in the manned spaceflight program, it may be that almost anything associated with space exploration could be very hard to pay for in the coming years. Its looking like the government isn't going to have the money to pay for much of anything "optional", because of steadily increasing non-discretionary costs and steadily decreasing revenues.

President-elect Obama initially said he would defer Constellation to pay for improvements in education, but has since changed his position, saying he would ask for additional funding for NASA to accelerate development of Constellation.

It is very interesting that Obama did a near "about face" on NASA, and it is somewhat hard to determine what motivated the change. The most obvious and likely cause was the desire to win votes in Florida, which hosts much of NASA's infrastructure. Another scenario is that Obama became aware of the difficult and potentially embarrassing situation the country will face when the shuttles are retired and NASA must contract with Russia for access to the space station. A more improbable scenario is that Obama was briefed on how NASA's development of Constellation interrelates with some possible classified military space program.

But the apparent ultimate reality is that NASA wouldn't be planning to build a new version of Apollo if it had any better ideas. Given the record of the government in recent decades (since the 1960s) for building anything new and innovative, perhaps NASA is making a very smart decision by keeping the technological risk to a minimum.

But wouldn't it be great if we could recapture the spirit and the energy of NASA's "golden age", and strive to do something really new and exciting?

3 comments:

Jeri said...

It's my off-the-cuff opinion that money invested in initiatives like space travel are like Heinlein's Long Range Foundation - they end up paying off in the long run a hundredfold and more. NASA's early space travel efforts did so; the requirements of space travel accelerated our electronics and computer industry and the benefits are seen across the board.

I do hope that Obama's waffling commitment to a space program holds - I'd like to see it regain some prominence and momentum too.

Jim Wright said...

Constellation is a huge step backwards and shows just how hidebound and conservative NASA has become. True innovation is long long since been lost to NASA and is the now purview of men like Burt Rutan and Robert Zubrin. I also suspect that Constellation is driven primarily by defense contractors and aerospace hardware manufacturers who are used to building missiles and can't think beyond the spinoff applications to the military (I used to work on the military side of defense system procurement, Aerospace contractors always have a separate agenda from the project at hand. Always).

CW, You made a good point about aerodynamic spacecraft and the inherent dangers of the basic concept, and for that reason (and the shrinking budget) I can see NASA's desire to return to a less complex and less costly launch concept. Constellation isn't it though. Only the Orion crew module is reusable, and then only partially and the launch and mission control ground asset requirements are similar to the Shuttle and the Apollo program.

A much better concept would have been the
MD Delta Clipper
design - which flew very successfully as the unmanned proof of concept DC-X prototype (the DC-X was destroyed in a crash due to failure of a landing leg, not a flaw in the basic design). The DC-X testbed proved the Single Stage to Orbit concept was doable, and should have led directly to the DC-Y test platform and final Delta Clipper SSTO production ship. The concept was advanced yet simple, relatively cheap and required minimal infrastructure.

Why funding for this project was canceled is an exercise in the stupidity of letting politicians determine the best engineering solutions.

Great post, BTW, thanks.

CW said...

Jim:

Delta Clipper is worth its own post. I have my own conspiracy theories about the strange cancellation of the Delta Clipper, and NASA's competitor the X-33.

Both programs failed following very similar failures in oxidizer/fuel tanks - the LOX tank on the Delta Clipper and the Hydrogen tank on the X-33. It just seems really strange.

It seems terribly obvious that aerospike engines are the future of space travel, but Constellation ignores all the progress on aerospikes to literally re-use the engines (J-2's) from the Apollo program.

My big question now is will it work? Will "return to Apollo" get us back to the moon by 2020? If so, NASA's decisions have to look pretty good. If not, the big question becomes "what was the point?".

I wish I was more optimistic that Constellation will actually be successful.