NASA's Ladee Moon-bound For Atmosphere Study

By Frank Morring, Jr. morring@aviationweek.com
Source: AWIN First
September 09, 2013
Credit: NASA

Planetary scientists are preparing for at least 100 days of intensive study in the Moon’s tenuous atmosphere, after a spectacular nighttime launch from Wallops Island, Va., on a solid-fuel Minotaur V rocket that was visible up and down the U.S. East Coast.

Built by NASA’s Ames Research Center, the 383-kg (884-lb.) Lunar Atmosphere and Dust Environment Explorer (Ladee) gave its handlers a few bad hours right after its Sept. 6 liftoff when fault protection limits shut down the spacecraft reaction wheels. Controllers disabled the fault limits and restarted the wheels, allowing spacecraft checkout to continue.

The next scheduled maneuver will come on or about Sept. 11, when the spacecraft’s on-board propulsion system will fire to push Ladee out of its highly elliptical Earth orbit into a trajectory governed by lunar gravity that will pull it into orbit around the Moon.

Launch from the seaside pad at the Wallops Flight Facility came at 11:27 p.m. EDT, the opening of the mission’s five-day launch window. A clear, moonless night gave observers from South Carolina to Nova Scotia a view of the five-stage rocket as it streaked up the coast. At ground level in Washington, D.C., due west of the launch site, the first three stage burnouts and the second and third-stage ignitions were visible to the unaided eye.

Ladee is built on NASA’s Modular Common Spacecraft Bus to explore the very thin atmosphere that surrounds the Moon — described as comparable to Earth’s atmosphere at the altitude of the International Space Station — to learn more about its composition, and the lunar dust believed to be lofted into the near-Moon environment by electric charges that develop on the surface at the day/night terminator.

During its 40-day commissioning period at the Moon, when it will orbit at an altitude between 200-300 km (124-186 mi.), Ladee’s Lunar Laser Communications Demonstration will test techniques for high-bandwidth datalinks using laser light. Once commission is complete, its three instruments will spend 100 days collecting science data on the atmosphere and dust environment. An ultraviolet and visible light spectrometer from Ames Research Center in California and a neutral mass spectrometer from Goddard Space Flight Center in Maryland will determine the atmosphere’s composition and variations. The Lunar Dust Experiment supplied by the Laboratory for Atmospheric and Space Physics at the University of Colorado/Boulder will capture and analyze lunar dust, which may be responsible for the glow that Apollo astronauts in lunar orbit saw just before sunrise.

During the mission’s science phase the spacecraft will dip to as close as 20 km to the surface. After 100 days the spacecraft will use its dwindling propellant supply to maneuver toward an untargeted impact with the Moon’s surface.


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