![]() ![]() Range was reconfigured for omni antennae instead of tracked ones to support 99 degree azimuth.Īn issue with the rocket's propulsion system was detected while the Delta 2 rocket was drained of fuel.Īnimation of GRAIL-A 's trajectory around Moon from 31 December 2011 to 30 April 2012 Mission profile Launch attempts Ī weather balloon was released minutes before the decision point to take the latest readings of upper level winds and Air Force weather reconnaissance aircraft were aloft beginning at 7 am. The propulsion subsystem consisted of a main fuel tank and a Re-repressurization system which were activated shortly after lunar orbit insertion. Įach spacecraft was fueled with 103.5 kilograms (228 lb) of hydrazine to be used by the thrusters and main engine to enable the spacecraft to enter lunar orbit and transition to the science phase of its mission. Thrusters aboard each spacecraft were capable of producing 22 newtons (4.9 lb f). Click here for a MoonKAM photo from lunar orbit. Each MoonKAM system (one per spacecraft) consists of a digital video controller and four camera heads. Moon Knowledge Acquired by Middle school students (MoonKAM).90% of the GRACE software was reused for GRAIL. K a band Lunar Gravity Ranging System (LGRS), derived from the Gravity Recovery and Climate Experiment (GRACE) instrument.The knowledge acquired will aid understanding of the evolutionary history of the terrestrial planets and computations of lunar orbits. ![]() On 5 December 2012 NASA released a gravity map of the Moon made from GRAIL data. A second phase, at a lower altitude, of data collection began 31 August 2012, and was followed by 12 months of data analysis. The data collection phase of the mission lasted from 7 March 2012 to, for a total of 88 days. Place limits on the size of the Moon's inner core.Constrain the deep interior structure of the Moon.Ascertain the temporal evolution of crustal brecciation and magmatism.Determine the subsurface structure of impact basins and the origin of lunar mascons.Understand the asymmetric thermal evolution of the Moon.Map the structure of the lunar crust and lithosphere.The gravitational field of the Moon was mapped in unprecedented detail. Changes in distance as small as one micrometre were detectable and measurable. The two spacecraft were able to detect very small changes in the distance between one another. By measuring the change in distance between the two spacecraft, the gravity field and geological structure of the Moon was obtained. Įach spacecraft transmitted and received telemetry from the other spacecraft and Earth-based facilities. The winning names, Ebb and Flow, were suggested by 4th grade students at Emily Dickinson Elementary School in Bozeman, Montana. Nearly 900 classrooms from 45 states, Puerto Rico and the District of Columbia, participated in the contest. Upon launch the spacecraft were named GRAIL A and GRAIL B and a contest was opened to school children to select names. As of August 5, 2011, the program had cost US$496 million. NASA's Jet Propulsion Laboratory managed the project. Maria Zuber of the Massachusetts Institute of Technology was GRAIL's principal investigator. Massachusetts Institute of Technology, LMSS Artist's interpretation of the GRAIL tandem spacecraft above the lunar surface.
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