What's Up for September 2011?
Jane Houston Jones: What's Up for September. Enjoy a tour of lunar landing sites as NASA's GRAIL mission launches to the moon this month.
Hello and welcome. I'm Jane Houston Jones at NASA's Jet Propulsion Laboratory in Pasadena, California.
The moon is easily visible in everyone's night sky in the first part of September.
Look for the areas where all six of the Apollo missions landed on the moon.
You won't see the landers, flag or footprints, but it's fun and easy to see these historic areas
with your own eyes or with binoculars.
On the sixth, look for three dark, smooth maria -- or seas. The middle one is the Sea of Tranquility or Mare Tranquillitatis. Apollo 11 landed very near a bright crater on the edge of this mare in 1969.
The Apollo 15, 16 and 17 landing areas form the points of a triangle above and below the Apollo 11 site.
On the seventh, you'll be able to see the bright crater Copernicus.
Just below it are the landing sites of Apollo 12 and 14.
Sound: rocket launch. Jones: NASA's twin lunar probes, GRAIL-A and GRAIL-B, will launch on September 8.
GRAIL stands for Gravity Recovery And Interior Laboratory.
The two GRAIL spacecraft will be launched together and then will fly similar, but separate, trajectories to the moon after they separate from the launch vehicle.
It took astronauts about three days to get to the moon. But the two GRAIL spacecraft will take more than three months and won't arrive until Dec. 31, 2011, and Jan. 1, 2012.
This longer flight path allows GRAIL to arrive with a lower velocity and reduces the amount of propellant needed to get the spacecraft into orbit around the moon.
The two spacecraft will orbit the moon in formation to determine the structure of the lunar interior from the moon's crust to its core.
Each GRAIL spacecraft is about the size of a washing machine. And they're not identical twins.
They have minor differences resulting from the need for GRAIL-A to follow GRAIL-B as they circle the moon.
This Gravity Recovery And Interior Laboratory mission will create the most accurate gravitational map of the moon to date.
Accurate knowledge of how the moon's gravity varies from place to place will also be an invaluable navigational aid to future lunar spacecraft.
Next month you can celebrate International Observe the Moon Night on Oct. 8. The moon will then appear exactly as it does on the 8th of this month.
You can read about gravity in the solar system at solarsystem.nasa.gov/yss for Year of the Solar System.
You can learn about the GRAIL mission at grail.nasa.gov
And you can learn about all of NASA's missions at www.nasa.gov.
That's all for this month. I'm Jane Houston Jones.
NASA Jet Propulsion Laboratory, California Institute of Technology