GRAIL

ODE: Moon

The primary objective of the GRAIL mission is to obtain accurate global models for the mean components of the Moon's gravity field. This objective will be achieved by making measurements of inter-satellite range and its derivative for co-planar, low altitude, near-polar orbiting satellites, using the Lunar Gravity Ranging System (LGRS) instrumentation, which includes the Radio Science System (RSS). All raw data transmitted by the twin spacecraft are collected by the Deep Space Network (DSN) and processed to higher level products by the GRAIL Science Data System (SDS) at JPL and GRAIL Science Team members at their respective institutions.

There are two payload elements on each GRAIL orbiter: the Lunar Gravity Ranging System (LGRS) which is the science instrument, and the MoonKAM lunar imager which is used for education and public outreach. The LGRS is based on the instrument used for the Gravity Recovery and Climate Experiment (GRACE) mission [32], which has been mapping Earth's gravity since 2002. The LGRS is responsible for sending and receiving the signals needed to accurately and precisely measure the changes in range between the two orbiters. The LGRS consists of an Ultra-Stable Oscillator (USO), Microwave Assembly (MWA), a Time-Transfer Assembly (TTA), and the Gravity Recovery Processor Assembly (GPA).

Search Grail mission data in Lunar ODE: Product Search • Map Search