PACE Successfully Completes Key Environmental Test

Consider it the “mother of all tests.”

This summer, the PACE spacecraft (short for Plankton, Aerosol, Cloud, ocean Ecosystem) completed a critical phase of its launch journey: the thermal vacuum test (TVAC), where it was subjected to extreme temperatures and pressures in a specialized chamber at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.

The objective? To verify the performance of the satellite once it’s launched and operational.

“This is the best way to simulate what PACE will experience in space,” said Craig Stevens, spacecraft systems lead. “Space is a vacuum, and the observatory is exposed to extreme temperatures. We must make sure PACE is ready for that environment.”

After months of round-the-clock shifts, numerous protocols, and a lot of team synergy, the mission completed its environmental testing in August, making it one step closer to launching in early January 2024.

“This proves the PACE observatory can withstand the rigorous thermal environment once it is launched and inserted into its operational environment,” said Mark Voyton, the mission project manager. “Completing the TVAC test is extremely significant, as it represents the last environmental test in our six-month environmental test campaign.”

The perspective of the image is from the top of the chamber peering down, looking into the chamber at the observatory. The inner walls of the test chamber are black, and the observatory, centered in the image and in the chamber, contrasts that darkness with copper-colored reflective material shining against the black. There are four scientists in white protective clean suits around the observatory and wires scattered on the floor connecting to the observatory and the chamber walls.
An overview of the PACE satellite entering a thermal vacuum chamber. Before the doors closed, the whole observatory was run through additional testing. Image Credit: NASA’s Goddard Space Flight Center/Denny Henry

Getting to this final test was a challenge for team members given the time and resources TVAC can take.

Before things could begin, the satellite was placed in the thermal chamber for a week earlier in June at NASA Goddard for setup.

Before the door for testing was closed, each team that had worked on PACE verified their part of the observatory was in working order, said Daniel Powers, PACE’s thermal product development lead. Members of the control room were also standing by to ensure that when the power for thermal testing went on, things worked properly. 

Once the chamber door closed, official testing lasted about 33 days.

The camera peers through parts of the observatory, focusing on an engineer who is looking intently at parts of the observatory. The engineer is wearing white protective clean gear that covers up over his head, and also includes a mask, so the only part of his face that is seen are his glasses-covered eyes. The parts of the observatory surrounding the scientist are a glimmering silver color.
Gary Davis, the missions systems engineer for PACE, examines the observatory before critical testing. Image Credit: NASA’s Goddard Space Flight Center/Denny Henry

“This is the final verification that everything is working on the spacecraft as expected. We take it to temperature extremes as well,” said Powers. “By taking it to the expected extreme environments we will see on orbit, we can see that we have everything setup and designed properly from a thermal perspective.”

The team worked three shifts – covering 24 hours each day, every day – to ensure operations ran on a strict timetable.

“You have a full marching army, and it’s all hands-on deck,” Powers said. 

A majority of the image is taken up by the observatory, primarily from the left side of the image. The complex pieces of the observatory are surrounded by wires and reflective foil-like material. Centered in the image is a red piece of equipment on the observatory, stoutly cylindrically shaped. To the right of the image stands a scientist in a full white protective suit. They stand feet slightly apart with hands resting on their hips, in a superman-like pose.
Members of the PACE team continue testing in Goddard’s TVAC chamber. Image Credit: NASA’s Goddard Space Flight Center/Denny Henry

PACE now has two more tests at ambient temperature and pressure, which complete the observatory’s post-environmental testing. Then the team begins preparing for the spacecraft’s journey to Florida and its launchpad.

Header image caption: The PACE observatory enters a thermal vacuum chamber at NASA’s Goddard Space Flight Center in Greenbelt, Md. It stayed in the chamber for 33 days of testing. Image Credit: NASA’s Goddard Space Flight Center/Denny Henry

By Sara Blumberg, NASA Oceans Communications Lead at NASA’s Goddard Space Flight Center