Sample return, however, isn't the only objective for the mission. This asteroid crosses Earth orbit, and the International Astronomical Union's Minor Planet Center has officially classified RQ36 as a "potentially hazardous asteroid," with a slight chance one in 1,800 of an impact in the year 2170.
"We'll orbit RQ36 for about a year to analyze its surface and select a sample site. This will give us experience with operating spacecraft in the vicinity of an asteroid, experience that will be useful if we ever have to send a mission to deflect one," said Nuth.
Piloting a spaceship near an asteroid is not easy. Most are lumpy and rotate more rapidly than planets, which makes for challenging landings. These small objects have feeble gravity, so other forces can significantly influence the spacecraft's position.
"Gravity on this asteroid is so weak, if you were on the surface, held your arm out straight and dropped a rock, it would take about half an hour for it to hit the ground. Pressure from the sun's radiation and the solar wind on the spacecraft and the solar panels is about 20 percent of the gravitational attraction from RQ36. It will be more like docking than landing," adds Nuth.
The mission will also help to better track the orbits of asteroids that might hit Earth by accurately measuring the "Yarkovsky effect" for the first time. The Yarkovsky effect is a small push on an asteroid that happens when the asteroid absorbs sunlight and emits heat. The small push adds up over time, and it is uneven due
|Contact: Bill Steigerwald|
NASA/Goddard Space Flight Center