Said Rick Homans, executive director of , where Galactic is the anchor tenant: “I think that as the industry moves forward, it wants to do this in the cleanest way possible and avoid any kind of damage to the planet.”
Virgin Galactic is competing with several other companies in California and the Southwest to be the first in commercial space, including XCOR in Mojave, California; Armadillo Aerospace in Rockwall, TX; Sierra Nevada Corp. in Sparks, NV; Masten Space Systems in Mojave, CA; and SPACEX in Hawthorne, CA. There’s also a broker, Space Adventures, in Vienna, VA.
Galactic deliberately chose to use hybrid rocket fuel, which combines the properties of liquid and solid rocket fuel, Whitesides said. Galactic also constructed its space vehicles from an all-carbon composite because it’s lighter and can take a smaller engine, requiring less propulsive force, and therefore less fuel.
“These are choices we’ve made that have a lower environmental impact,” Whitesides said.
Criticism of Study, and a Response
Whitesides had two major criticisms of the study. “One of the things that’s a little disappointing is that the authors didn’t include a range of uncertainty in their model,” he said. “What’s the confidence around that number? I don’t think we know that.”
“Given the lack of detailed knowledge of the microphysical rocket black carbon and an unknown growth rate of the space transport sector, we cannot place a formal uncertainty on our model,” Ross said. “There are no measurements of soot from rocket engines of any kind, whether they’re 50 years old or are going to be used 10 years from now.”
Whitesides also said the amount of fuel propulsion used in the simulation is twice what Virgin Galactic would use in a typical launch. Moroever, that amount—up to 20,000 pounds per launch—is a fraction of what is employed in current global rocket launches. “The [NASA] shuttle flies five times a year, so you’re talking about five million pounds of solid propulsion being burned every year—which is roughly a thousand times one of our flights. And they’ve been doing it for 30 years.
“I don’t think anyone is attributing a .4 degree change in temperature to the space shuttle program,” Whitesides said.
Ross said the Space Shuttle has been the subject of a “modest amount” of scientific inquiry, which he has been involved in, since the 1990s. It focused on the impact of chlorine from solid rocket fuel on the ozone layer. “I am not aware of scientific studies of the climate impact of solid rocket motors of the type that the Space Shuttle uses,” Ross said.
Both Whitesides and Homans said they may be among the industry representatives at a conference The Aerospace Corporation is planning to host in January. The details are still being developed, but the emissions issue will be front and center at that conference, according to an Aerospace Corporation spokesman.
Industry positions will be key indicators for how the emerging sector handles concerns about emissions, said NRDC’s Lovaas. “It’s kind of an extra burden on the leaders in this new industry to make sure they’re responsible,” he said. “A lot of people are going to be paying attention.”
Image: Mike Miley via flckr Creative Commons license