LADEE Project Manager Update
20 Mar 2013
Engineers at NASA's Ames Research Center, Moffett Field, Calif., are about to begin the Thermal-Vacuum (TVAC) phase of environmental testing on NASA's Lunar Atmosphere and Dust Environment Explorer (LADEE) Observatory. During the TVAC environmental testing phase, LADEE will undergo a variety of rigorous tests that simulate the full range of extreme temperatures and vacuum the spacecraft will experience during the course of its mission.
Previous mechanical tests confirmed the LADEE Observatory is able to withstand the loud shaking conditions the spacecraft will endure during its launch, including acoustic, vibration, and shock.
LADEE also has completed a Comprehensive Performance Test, which confirmed everything is working properly after the mechanical testing, and also established a baseline for the spacecraft before going into TVAC testing.
Engineers are preparing the observatory for chamber closure and TVAC testing the week of March 18, 2013. During the TVAC test phase, the observatory will be mounted inside a large vacuum chamber at NASA Ames, and the chamber will be depressurized to create a vacuum.
Engineers then will use a heating system to simulate the strong, direct sunlight shining onto the spacecraft and the resulting heating of the parts facing the sun. The system will heat the parts of the observatory to their highest expected temperatures, near 140 degrees Fahrenheit (60 Celsius).
Once the heating phase of the TVAC test is complete, engineers will turn off the heating system and the chamber will cool the various components down to their lowest expected temperatures, near -58 degrees Fahrenheit, or -50 degrees Celsius. This will subject LADEE to the coolest temperatures engineers expect the spacecraft to experience in space.
Engineers then will use the heating system to heat up different sides of the observatory during a sequence simulating the sun's varying positions around the spacecraft as it orbits from the light to dark side of the moon.
Once engineers complete all of the temperature testing, which will take several weeks, the vacuum chamber will slowly re-pressurize until it is safe to open. After the chamber is open, engineers will inspect LADEE and begin communications performance testing and a final comprehensive performance test to confirm that everything successfully survived the TVAC tests.
-- Butler Hine, LADEE project manager
Ames Research Center, Moffett Field, Calif.