Is Virgin Galactic's Claim To Be Green Reasonable? Actually, Sort Of
Flight photos Mark Greenberg via boingboing
It must have been a beautiful sight, the maiden flight of the Enterprise. Burt Rutan says that it "signifies the start of what we believe will be an extremely exciting and successful spaceship flight test program." The space travel we dreamt of as kids is finally getting close. Virgin also calls it green, saying that in Autopia that it has "an incomparably smaller environmental impact, lower cost and greater flexibility than anything that has gone before"
But some are not so happy; in the Guardian, Leo Hickman wrote last fall that It's not rocket science: leaving the planet costs the Earth. (Treehugger covered it here)
Hickman didn't believe Virgin's claims that "it has built a "clean spaceship" and that the "CO2 emissions per passenger on a spaceflight will be equivalent to approximately 60% of a per passenger return commercial London/New York flight". He concludes:
Why doesn't Virgin Galactic just call it as it is? Sure, sell your dreams of space flight to the super-rich if you must - I'm as drawn to the boyish wonder of it all as the rest of them - but let's not keep up the pretence that it isn't one of the most extravagant and self-centred uses of a fossil fuel imaginable.
Virgin Galactic responded to Hickman; Sami wrote about it and quoted President Will Whitehorn:
The company is developing a 21st-century space launch system based on the principles of an entirely carbon composite construction, a unique benign hybrid rocket motor, biofuels where permissible and very high-altitude air launch and firing of the benign rocket rather than launching it from the ground. The air launch negates the need to use dirty carbon-intensive solid chemical fuelled rocket boosters. The result is a very low-energy and low environmental impact approach to getting humans, scientific payload and eventually even small satellites into space.
Triple Pundit picks up the story, and gets it wrong. They write:
Indeed, space exploration is an expensive, fuel-intensive, and polluting venture. Rockets and spacecraft need liquid hydrogen fuel, which at first appears to be clean-burning. However, one kilogram of liquid hydrogen requires 15 kilowatt hours of electricity, and a space shuttle launch blasts about 113 tons of it at takeoff: the equivalent of what 130 American homes' electricity need for an entire year. Add the 28 tons of carbon and 23 tons of particulates that are belched around Florida's Kennedy Space Center, and you have a very dirty science program.
Except Virgin Galactic isn't using either liquid hydrogen and oxygen, or the filthy solid fuel rockets that dump tons of perchlorates and aluminum into the atmosphere and our water.
Liquid fuel rockets are controllable but seriously explosive, and solid fuel rockets cannot be shut off or controlled very well once they are fired up. So they are using a hybrid rocket, which combines a solid fuel with a liquid oxidizer.
The solid is a type of rubber called hydroxy-terminated polybutadiene, or HTPB. The oxidizer is Nitrous oxide. According to an article in Space.com back when the hybrids were first being tested, besides being a lot safer,
The system also touts a somewhat cleaner way to reach space. Its byproducts -- water vapor, carbon dioxide, carbon monoxide and nitrogen -- are preferable to the waste produced by the shuttle's solid rocket boosters, which burn ammonium perchlorate and aluminum.
Is it green? No, of course not. As I noted in Contradiction in Terms Dept.: a LEED Certified Spaceport:
Tourists and passengers will drive into the middle of the desert, where Richard Branson and others will literally burn rubber, mixed with nitrous oxide, to fire people into space for seven minutes at $ 200,000 a pop.
But It may well be, as Virgin says, greener than any spaceflight that has gone before.