Flying on its last bit of fuel, NASA’s Deep Impact probe is carefully reshaping its course toward a potentially hazardous near-Earth asteroid in hopes the spacecraft can survey the body in January 2020.
Engineer’s don’t know if Deep Impact has enough fuel to reach the asteroid, and NASA officials in Washington have not committed to funding the extended mssion.
But that isn’t stopping engineers from trying, according to Tim Larson, Deep Impact’s project manager at the Jet Propulsion Laboratory in Pasadena, Calif.
“There is a lot of uncertainty whether we’ll be able to pull this off,” Larson said in an interview with Spaceflight Now.
Engineers estimate there are just 4.4 pounds, or 2 kilograms, of hydrazine fuel left inside Deep Impact’s propellant tank. About 190 pounds of fuel were inside Deep Impact when it blasted off in January 2005.
NASA management in Washington gave the Deep Impact team authority to fire the spacecraft’s thrusters for 140 seconds on Nov. 24, changing the probe’s velocity 19.7 mph and changings its trajectory around the sun.
The burn started aiming Deep Impact toward asteroid 2002 GT, a mystical object that regularly crosses paths with Earth. It could be a target for future human expeditions and it has a risk of one day colliding with Earth.
Discovered in 2002, the asteroid is nearly one-half mile wide. But scientists do not know what it looks like or its composition.
A smaller burn by Deep Impact in October 2012 would finish targeting asteroid 2002 GT, setting up for a high-speed flyby in January 2020, Larson said.
“Unfortunately because of the small amount of fuel we have left, we’re pretty limited on our choices of where we can go,” Larson said.
Scientists at the Jet Propulsion Laboratory identified asteroid 2002 GT as the best opportunity to continue the Deep Impact mission, which completed its first extended phase early this year.
“We did a search of a catalog of available bodies that could be reachable with the fuel we have available,” Larson said. “Out of that, about a half-dozen potential bodies came up that we may be able to get to. This is the one that seemed most feasible to get some decent observations and science.”
Deep Impact is about the size of a sport utility vehicle. It fired a high-speed impactor into comet Tempel 1 in July 2005, blowing a hole in the nucleus and spraying icy debris into space. The Deep Impact mothership continued flying, and NASA offered the craft for scientists to propose new missions.