Science operations for the Mini-RF radar on NASA’s Lunar Reconnaissance Orbiter are on hold now that the instrument is not transmitting sufficient energy to image the moon’s surface. The mission team continues to gather and analyze data in an attempt to determine the cause of the fault and whether it is recoverable.
Launched aboard LRO in June 2009, Mini-RF (short for Miniature Radio Frequency) has spent 18 months successfully mapping the moon. Original mission plans called for Mini-RF to gather two 6- by 240-mile “strips” of data per month; the instrument has since collected more than 2,000 strips of data covering about two thirds of the lunar surface, including 98 percent of both polar regions. Instead of the planned two hours of science collection, Mini-RF has gathered more than 400 hours of science data.
Mini-RF also collected the first radar images of the lunar far side –the hemisphere of the moon that is never visible from Earth – and imaged the floors of permanently shadowed impact craters that can’t be seen from Earth. More than 38 terabytes of data have been delivered so far to NASA’s Planetary Data System archive, where it is available to lunar scientists and the general public.
Mini-RF has proven that a small, lightweight synthetic aperture radar instrument can be part of a larger payload, instead of requiring a dedicated spacecraft (as was needed on past radar missions, such as Magellan to Venus). Meeting another mission goal, Mini-RF operated in a communications mode, able to transmit and receive signals from Earth – a technology that could allow future missions to save mass and power.
Mini-RF was developed and built by the Naval Air Warfare Center and several other government and commercial contributors, including Sandia National Laboratories, Raytheon, Northrop Grumman and BAE Systems. The Johns Hopkins University Applied Physics Laboratory, Laurel, Md., performed the final testing and integration of the instrument and runs the day-to-day science operations.