NASA’s LADEE spacecraft reaches Moon month after launch
NASA’s latest lunar probe, the Lunar Atmosphere and Dust Environment Explorer (LADEE), successfully entered a stable lunar orbit on October 6, 2013, following its September 7, 2013 launch from Wallops Flight Facility, Virginia. Despite the partial federal government shutdown that idled an estimated 97 percent of the NASA workforce, sufficient “excepted” engineers and technicians at the NASA Ames Research Center and the Goddard Space Flight Center were permitted to continue guiding LADEE as planned.
LADEE took a rather unusual approach in its transit of the Moon. Launched into a highly elliptical Earth orbit, the spacecraft made three increasingly-larger laps around Earthbefore getting close enough to enter into Lunar orbit. These three”phasing orbits” of Earth allowed the spacecraft to gain velocity for the trans-Lunar injection, which occurred at perigee of the third orbit,, at which point LADEE’s engine fired to increase the altitude of its apogee to within the Moon’s sphere of influence.” After a long coast phase, Lunar orbit insertion (LOI) occurred using another three-minute engine burn.
Two further burns are planned, tentatively on October 9 and October 12, to position LADEE into a circular obit around the moon’s equator. There, it will begin its nominally 100-day mission to use instruments aboard the spacecraft to study the lunar exosphere and dust in the Moon’s vicinity.
LADEE, the first spacecraft designed, developed, built, integrated and tested at NASA’s Ames Research Center in Moffett Field, Calif., was launched aboard a Minotaur V rocket. The Minotaur V, provided by the U.S. Air Force, was a repurposed three-stage Peacekeeper Missile to which Orbital Sciences Corp., Dulles, Va., added two additional stages and new avionics and guidance software. Aerojet Rocketdyne built the SR119 Peacekeeper second stage solid rocket motor that helped launch LADEE into an Earth-centric trajectory.
Explained Warren Yasuhara, Aerojet Rocketdyne’s Vice President of Space Systems, “From the crewed Apollo vehicle to the orbiters of Lunar Prospector and LADEE, Aerojet Rocketdyne provides propulsion and power for lunar exploration. LADEE is designed to characterize the tenuous lunar atmosphere and dust environment–an important study in preparation for returning astronauts to the Moon.”
The roughly $280 LADEE mission, initially announced as part of NASA’s FY2009 budget, has three major science goals:
- Determine the global density, composition, and time variability of the tenuous lunar exosphere before it is perturbed by further human activity.
- Determine if the Apollo astronaut sightings of diffuse emission at tens of kilometers above the surface were sodium glow or dust.
- Document the dust impactor environment (size-frequency) to help guide design engineering for the outpost and also future robotic missions.
The science payload consists of:
- Neutral Mass Spectrometer (NMS), that will perform in situ measurements of exospheric species. The instrument has heritage from the SAM instrument on the Mars Science Laboratory.
- UV-Vis Spectrometer (UVS), that will measure both the dust and exosphere. The instrument has heritage from the UV-Vis spectrometer on the LCROSS mission.
- Lunar Dust EXperiment (LDEX), that will directly measure dust. The instrument has heritage from instruments on Galileo, Ulysses and Cassini.
- LADEE also carries a technology demonstration payload for testing an optical communication system. The Lunar Laser Communication Demonstration (LLCD) will use a laser to transmit and receive data as pulses of light, much the same as data is transferred in a fiber optic cable, to three ground stations. This method of communication has the potential to provide five times the current data return, as compared to radio frequency communication, from both LADEE and future missions. The technology is a direct predecessor to NASA’s Laser Communication Data Relay (LCDR) satellite due to launch in 2017.
Due to the partial government shutdown, comment from NASA will not be available until NASA reopens.
Jim Siegel comes from a business and engineering background, as well as a journalistic one. He has a degree in Mechanical Engineering from Purdue University, an MBA from the University of Michigan, and executive certificates from Northwestern University and Duke University. Jim got interested in journalism in 2002. As a resident of Celebration, FL, Disney’s planned community outside Orlando, he has written and performed photography extensively for the Celebration Independent and the Celebration News. He has also written for the Detroit News, the Indianapolis Star, and the Northwest Indiana Times (where he started his newspaper career at age 11 as a paperboy). Jim is well known around Celebration for his photography, and he recently published a book of his favorite Celebration scenes. Jim has covered the Kennedy Space Center since 2006. His experience has brought a unique perspective to his coverage of first, the space shuttle Program, and now the post-shuttle era, as US space exploration accelerates its dependence on commercial companies. He specializes in converting the often highly technical aspects of the space program into contexts that can be understood and appreciated by average Americans.