The simmering debate over the future direction of our nation's human space flight program hit even more air turbulence over the past couple weeks. On the cusp of the Augustine Report on NASA's future space flight plans (that was delivered to the White House last month to await a presidential decision), the debate has gotten more polarized in publications and Internet articles -- even with thinly veiled allegations of deception.
On an uplifting note, this week the space shuttle Atlantis had a flawless launch and rendezvous with the International Space Station on another milk run carrying 15 tons of spare parts and supplies. This is the last scheduled shuttle mission to ferry crew to or from the ISS. Until a shuttle replacement starts flying sometime before the end of the next decade, astronauts will ride Russian Soyuz capsules to the station. Ticket price: $50 million per seat –- round trip of course.
And just a week earlier Time Magazine awarded the shuttle's planned successor, the Ares-1 rocket, the "Best Invention of 2009." Time cited it as a "worthy descendant" of the rocket lineage: "lightweight composites, better engines and exponentially improved computers give it more reliability and power." (This reads like an auto showroom brochure.)
But none other than the second man to walk on the moon, Buzz Aldrin, bluntly asserted that the Ares test flight last October 27 was more for boosting the new rocket's sagging PR image rather than for the next-generation of space flight. In a blistering editorial in the Huffington Post, Aldrin said that the Ares 1-X prototype that blazed skyward was largely dead weight: a mock upper stage, a mock Constellation capsule, and mock solid rocket motor segment. Aldrin accused NASA of "sleight-of-hand" and "dead-end" rocketry.
Aldrin feels that NASA should leave the chore of transporting humans to low Earth orbit to the private sector –- just as the Augustine commission does. Space tourism is often cited as a potential commercial market for weekend astronauts. But in this week's Space News, two European Space Agency flight managers, Fredrick Engstrom and Heinz Pfeffer, chimed in to say that off-Earth tourism is a fraud.
Simply do the math say the authors. One of the most efficient heavy lift rockets in operation is the Ariane 5. But –- like all chemically propelled rockets -– a whopping 85 percent of the vehicle is fuel, 10 percent expendable tank structure, leaving only 5 percent for payload. At $200 million a launch, tickets would have to run as much as $40 million a passenger depending how many people you could squeeze onboard. This isn't exactly a romantic weekend getaway special.
For decades there has been a lot of discussion of dramatically lowering launch costs with a single-stage-to-orbit (SSTO) vehicle that would not dump most of its hardware into the ocean. NASA's X-33 was to be the prototype, but was cancelled in 2001. It was bedeviled by a variety of technical problems and never flew. What's more, NASA's aerospace partner on the project, Lockheed-Martin Corp., began to question the commercial viability of the X-33's planned successor, the VentureStar. It would have been the world's first privately operated SSTO space cruiser.
To realize a practical SSTO, engineering breakthroughs are
needed to overcome the exorbitant cost of just getting off the ground. Many
options have been considered over the decades: accelerating a vehicle along a
launch rail, having it ride skyward on a powerful laser beam which heats a
working fluid, or using a nuclear reactor to heat propellant. (The ultimate
answer is a space elevator, but that dream is farthest into the future.)
Pound for pound a nuclear powered shuttle would be twice as efficient as a chemical rocket and therefore launch a larger payload at less cost per pound. A working fluid, typically hydrogen, would be pumped through narrow channels in a small hot fission nuclear reactor and heated into high-energy plasma ejected from the ship.
The most promising concept is the so-called Particle Bed Reactor that has been under study by the U.S. Defense Department. Though this would be derided and politically blocked as "Chernobyl in the sky," the effects to Earth would be small even following a worst-case accident say some engineers.
This week Russia's space chief, Anatoly Perminov, proposed building a nuclear powered interplanetary rocket to carry humans to Mars. Perminov said the preliminary design could be ready by 2012, and then it would take nine more years and cost the equivalent of $600 million (U.S.) to build the ship. President Dmitry Medvedev backed the project and urged the Russian government to find the money.
But as long as we stick with chemical propulsion we will remain in the covered wagon days of space travel. "They'll [NASA] probably keep the International Space Station going out of bloody-mindedness. The shuttles will fly a few more times. There will be some vague plans, more studies. Robots, of course, but no concerted attempt to look for alien life, the most compelling raison d'être for space exploration," wrote British science editor Michael Hanlon in this week's New Scientist magazine.
Our unwillingness to consider something as bold as nuclear propulsion would be as misguided as if our ancestors turned down steam locomotives for transcontinental travel. If you've ever watched a space shuttle take off on its Promethean flame you dramatically realize that space travel requires truly furious levels of raw energy to scramble out of the Earth's gravitational field. Frontier exploration isn't an adventure for the timid, as our pioneers well knew.
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