12 September 2011
Credit: NASA/Darrell McCall
On 10 September 2011, NASA launched its new lunar mission, the Gravity Recovery and Interior Laboratory (GRAIL). GRAIL will study the Moon’s gravitational field and internal structure. The mission consists of two small spacecrafts, and will last 90 days. The GRAIL spacecrafts were launched aboard a powerful Delta II rocket, from Cape Canaveral Air Force Station, in Florida.
The GRAIL spacecrafts, termed GRAIL A and GRAIL B, will enter low polar orbits around the Moon. A polar orbit passes above or near the poles of its central object. While the Apollo manned missions took about three days to travel to the Moon, the GRAIL probes will fly to the Moon for more than three months. GRAIL A will arrive at the Moon on 31 December 2011, and GRAIL B will reach the Moon, a day later, on 1 January 2012. As they orbit the Moon, in tandem, at a very low altitude of approximately 50 km, the GRAILs will be about 200 km apart.
References
NASA
www.nasa.gov/
Wikipedia
Aymen Mohamed Ibrahem
Senior Astronomy Specialist