LADEE Project Manager Update
NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) Mission is making great progress towards its 2013 launch to explore the lunar environment. Work is being completed in parallel in five major areas: the radiator panel, the main structure of the spacecraft, the propulsion system, the instruments, and the launch vehicle.
The radiator panel is a flat octagonal metal panel that sits at the top of the spacecraft and holds almost all of the electronics, sensors, and power controls for the rest of the satellite. It is almost a small spacecraft all on its own; so integrating it is a major step for the LADEE Mission. Engineers at NASA’s Ames Research Center, Moffett Field, Calif., have pieced together the radiator panel with the avionics and power control unit, the battery, the star tracker, the inertial measurement unit, one of the two omni-antennas that allow us to command the spacecraft, the medium-gain antenna used to transmit science data to the ground, and a version of the flight control software. Other important components still to come are the communications transponder and two larger science instruments - the Neutral Mass Spectrometer (NMS), led by Paul Mahaffy at NASA’s Goddard Space Flight Center, Greenbelt, Md., and the Lunar Laser Communications Demonstration (LLCD) technology demonstration led by NASA Goddard and built by MIT Lincoln Labs.
The main spacecraft structure is a lightweight, yet extremely strong, metal composite frame that holds everything together. It will carry four reaction wheels to help steer the spacecraft, along with solar arrays that will help generate power to this structure. Before NASA engineers begin integrating it, the structure has to be tested to make sure it is strong enough for the launch loads. During the tests, the structure was placed on a special table designed to intentionally put the structure through rigorous conditions and test its strength; that’s when we encountered a problem - the test table gave an unexpected, big jolt to the structure. Amazingly, the structure held up to the jolt, but as a precaution, we switched to a second structure that had already been built for just this type of contingency. That second structure is now in strength testing and soon will go through a “bake-out,” which removes possible contaminants from it. Meanwhile, a big electrical harness that attaches to the main structure and carries power from the solar arrays to the radiator panel, as well with commands to the propulsion system, is assembled and has already completed its own bake-out.
The propulsion system, which will be used to travel to the moon and go into orbit around it to conduct science observations, completed its bake-out in May. Engineers then inspected the alignment of its thrusters and exercised its functions with simulated commands. Everything looks good, so we will soon begin to integrate it with the rest of the spacecraft at NASA Ames..
While the spacecraft is being tested and assembled, the science teams have been completing their work on the LADEE instruments. As each instrument is finished, it goes through a pre-shipment, or “pre-ship,” review to look at all of its test data and verification documentation, and approve its delivery for integration with the spacecraft. So far, the Lunar Dust EXperiment (LDEX) instrument led by Mihaly Horanyi at the Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, Colo., is all done, having wrapped up its pre-ship review. The UltraViolet Spectrometer (UVS), led by Tony Colaprete at NASA Ames, is following closely behind. Because these two science instruments will be integrated onto the radiator panel, they need to be completed soon. The NMS and the LLCD are still being tested and are scheduled to arrive in the fall.
Finally, Orbital Sciences Corp., is making progress on its design reviews of the Minotaur V launch vehicle that will lift LADEE into space. This month at NASA’s Wallops Flight Facility’s launch complex in Virginia, a team performed a Launch Vehicle Pathfinder. This is an important exercise that involved a large part of the LADEE team, to practice bringing the launch vehicle segments together at the launch range and stacking everything together as if preparing for the launch. This exercise demonstrated all of the transportation steps work, the equipment is ready, and that all the many parts fit together properly.
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