The PACE spacecraft completed a month of critical thermal testing at NASA's Goddard Space Flight Center, paving the way for its planned launch in January 2024. We could say this is the "mother of all tests". This summer, the PACE spacecraft (short for Plankton, Aerosols, Clouds, and Ocean Ecosystems) completed a critical stage in its launch journey: Thermal Vacuum Testing (TVAC), in which the spacecraft was subjected to extreme temperatures and pressures in a specialized test chamber at NASA's Goddard Space Flight Center in Greenbelt, Maryland.
NASA's PACE (Plankton, Aerosols, Clouds, Marine Ecosystems) spacecraft orbits above Earth. Image source: NASAGSFC
What's the purpose? Verify satellite performance after launch and operation.
The PACE observatory enters a thermal vacuum chamber at NASA's Goddard Space Flight Center in Greenbelt, Maryland. It was tested in the cabin for 33 days. Image source: NASA Goddard Space Flight Center/Denny Henry
"This is the best way to simulate what PACE will experience in space," said Craig Stevens, director of spacecraft systems. "Space is a vacuum, and the observatory will be exposed to extreme temperatures. We have to make sure PACE can adapt to this environment."
After months of day and night shifts, countless protocols and teamwork, the mission completed environmental testing in August, moving one step closer to launch in early January 2024.
Mission project manager Mark Voyton said: "This proves that the PACE observatory can withstand the rigorous thermal environment once it is launched and enters the operational environment. Completing the TVAC test is extremely significant because it is the last environmental test in our six-month environmental test campaign."
A full view of the PACE satellite entering the thermal vacuum chamber. Additional tests were conducted throughout the observatory before the hatch was closed. Image source: NASA Goddard Space Flight Center/Denny Henry
Considering the time and resources required for TVAC, conducting final tests was a challenge for team members. Before starting, the satellite spent a week setting up in a hot chamber at NASA's Goddard Space Flight Center in early June.
Daniel Powers, head of thermal product development at PACE, said that before the door closes on testing, each team involved in the PACE work will check whether the observatories they are responsible for are in normal working order. Members of the control room are also on call to ensure everything is working properly once the thermal test power is turned on.
PACE mission systems engineer Gary Davis inspects the observatory before a critical test. Image source: NASA Goddard Space Flight Center/Denny Henry
After the hatch was closed, formal testing lasted approximately 33 days.
"This is the last validation that everything on the spacecraft is working as expected," Powers said. "We also tested it with extreme temperatures. "By taking it to the expected extreme environments that we'll see in orbit, we can see that, from a thermal perspective, everything we set up and designed is correct. "
PACE team members continue testing at Goddard’s TVAC test facility. Image source: NASA Goddard Space Flight Center/Denny Henry
The team operates three shifts and works 24 hours a day to ensure strict compliance with the schedule.
PACE now needs two more tests at ambient temperature and pressure to complete the observatory's post-stage environmental testing. The team then began preparing the spacecraft for its journey to Florida and its launch pad.