GRAIL satellites launched today.
Grail went up on a Boeing-heritage ULA Delta II. It consists of two satellites which will fly in tandem, mapping the gravity field of the moon, from which may be inferred a great deal about the internal structure, from which may be inferred quite a bit about how the moon cooled.
Satellites built and day to day operations by Lockheed Martin. Lead scientist is Maria Zuber of MIT. Ms. Zuber says that US schoolchildren will be allowed to participate in a contest to name the two satellites; I will bet a fair number of "Spongebob and Patrick" nominations will be submitted.
More below the Orange Squiggle of Power.
NASA Press Kit on Grail (PDF).
GRAIL fact sheet (PDF)
The two spacecraft will fly at a nominal altitude of 50 kilometers (30 miles for the metric impaired) and separated by 200 kilometers (120 miles).
The two satellites also carry cameras, and middle school students will be allowed to submit nominations for what should be photographed.
Total cost is about $500M.
This I did not know: if earth did not have the moon, it would spin thrice as fast, and days would only last 8 hours.
The six science missions:
- Map the structure of the lithosphere
- Understand the moon's asymmetric thermal evolution
- Determine the subsurface structure of impact basins and the origin of mascons¹
- Ascertain the temporal evolution of crustal brecciation and magmatism
- Constrain deep interior structure from tides
- Place limits on the size of a possible solid inner core
1: A mascon is a "mass concentration", detected beneath certain impact craters by the perturbations induced in the orbits of lunar spacecraft.