Sunday, November 25, 2012
Associated Press
CLEVELAND
A government-industry team including engineers from government research facilities in Ohio will be testing a space propellant researchers say would be safer and more efficient than toxic fuel now powering satellite and spacecraft thrusters.
The test project aims to fly a small unmanned spacecraft in 2015 with modified thrusters powered by an experimental alternative fuel called AF-M315E, The Plain Dealer reported.
Engineers at Cleveland’s NASA Glenn Research Center and Dayton’s Air Force Research Lab will be helping test the alternative fuel as part of the $45 million “Green Propellant Infusion Mission.”
If the fuel performs as hoped, officials say it could pave the way for cheaper, cleaner satellites and spacecraft.
NASA, military and commercial satellites now use thrusters fueled with the fuel hydrazine to hold or alter their positions, but hydrazine fumes sickened astronauts on the final Apollo flight in 1975, and satellite and spacecraft fueling crews must take extraordinary precautions when handling the fuel — adding to already high launch costs.
“We think the payoff for this is going to be really huge if we can take the first step in getting rid of toxic propellant,” said Randy Lillard, an aerospace engineer with NASA’s Office of the Chief Technologist who’s leading the mission.
The demonstration mission, using a satellite about the size of a two-drawer file cabinet, will have to prove that AF-M315E works in real space conditions and show that its advantages outweigh the costs of making the switch.
“It has to work precisely, and every time,” Lillard said.
Special permits and driver training are required to transport hydrazine, which is stored in remote bunkers.
The ammonialike vapors can irritate throat and eyes, and a splash can cause a skin rash.
High-level or long-term exposure may damage the lungs, kidney, liver and nervous system and lead to tumors, seizures, coma or death.
Spacecraft fuel crews handling that fuel must wear full-body protective outfits.
Those protective measures contribute to the soaring costs of satellites as operators who use them for navigation, weather forecasting, global communication and national defense already face money crunches.
Testing has shown that AF-M315E is not a poisonous-vapor or cancer-causing risk, and officials say its use could open access to space for potential satellite operators now priced out of the market.
“It could allow customers from academia or small customers from the government to lower the cost of preparing and launching spacecraft into orbit,” said Brian Reed, an aerospace engineer with NASA Glenn’s space propulsion branch who’s part of the propellant team.
Another advantage is that AF-M315E doesn’t boil or explosively expand when exposed to the atmosphere and doesn’t require extra-thick tank walls. It’s denser than hydrazine, so its fuel tank can be as much as 40 percent smaller — freeing up satellite or spacecraft room.
Researchers say it’s also more efficient.
Rocket fuels are judged by specific impulse, a measure of the fuel amount needed to achieve a certain momentum — basically, a propellant’s pushing power. IAF-M315E has a higher specific impulse than hydrazine, requiring less of it to do the same amount of pushing.
A potential downside is that it burns much hotter than hydrazine.
Catalyst material that ignites the propellant and engine housings where the combustion occurs would have to be upgraded to withstand the higher temperature.
Lillard acknowledges it won’t be easy getting the propellant to flight in three years, but “it’s something we believe is important.”