NASA has put out a proposal for a greener fuel source for launching satellites, rockets and eventually space taxis. Space launches add “several kilotons” of carbon dioxide into the air each year. So far it isn’t a large percentage of the CO2 that gets spewed from cars, trains, planes and ships, but over the next several decades that could change. Because more governments and private enterprises are looking at space for new ventures, less harmful fuel is needed.
According to NASA the current fuel it uses is hydrazine. It is a highly toxic and corrosive fuel. It can be stored for long periods of time and provides the energy necessary for rocket launches but it is hazardous to the environment. NASA wants a cleaner greener alternative.
Madsci.org has an article that describes the four types of fuel normally used for rocket launches – solid, cryogenic, petroleum and hypergolic. The space shuttle used three of these types. According to Starts with a Bang, the solid fuel rocket used a noxious fuel called ammonium pecholorate composite that creates hydrogen chloride which mixed with water makes hydrochloric acid. The second fuel used was liquid hydrogen that expelled water vapor, by far the least toxic emission. The shuttles engines use a small amount of hypergolic fuel, relatively speaking, for maneuvering. That only covers the space shuttle and not the numerous rockets used for launching satellites and other items into space.
According to Slate, one of the dangers of rocket propellants it that they emit reactive gases that destroy the ozone, as well as soot and aluminum oxide that add to the problem. Crosslink commented that the build up of black soot in the stratosphere will last for years so multiple launches could accumulate more soot that absorbs sunlight. Most man made pollutants do not reach the levels that rocket exhaust does which creates unique problems.
Even though the amount of propellant burned by rockets—and so, too, their carbon dioxide emissions—is small compared to the fuel burned each year by the aviation industry, the accumulation of stratospheric soot could represent a net additional heating, or radiative forcing, on the atmosphere comparable to all of aviation.
Now start adding in more launches coming from more countries like China and you begin to see the problem. The fuels used for the ever increasing launches of GPS, defense, spy, and climate satellites is simply adding more stuff into parts of our atmosphere we previously had been unable to reach. Add to the those launches what some hope will be a burgeoning space tourist industry and we simply compound our climate change issues.
Unfortunately, liquid hydrogen is unable to be the only fuel used to lift rockets into the air thus NASA’s need to find other fuels that won’t produce the dangerous byproducts of the fuels used today.
Photo from NASA.Tags: greener fuel, NASA, rocket, rocket fuel