“Deployments don’t create moments of terror,” Townsend said. “Obviously, launch carries risk — the shock and the rates you see when you separate from the launch vehicle… And then getting the aperture door to open and deploy is another potential issue. But these are typical aerospace risks, not extraordinary, harrowing events for Roman.”
It also helps that Roman will fly with a primary mirror donated to NASA by the National Reconnaissance Office, the U.S. government’s spy-satellite agency. The NRO had originally ordered the mirror for a telescope intended to look down at Earth, but the agency no longer needed it. Before NASA acquired the surplus mirror in 2012, scientists working on the early design that became Roman were considering a smaller telescope.
The larger mirror makes Roman a more capable scientific instrument, and the NRO’s gift removed the risk of a delay or defect from manufacturing a new mirror. The trade-off was that NASA had to build a heavier spacecraft and select a larger rocket to carry it, which increased the observatory’s cost.
Tests of Roman’s components have gone well this year. Work at Goddard continued through the government shutdown in the fall. By contrast, Webb’s engineers uncovered problem after problem while trying to verify that observatory’s space performance: leaky valves, tears in Webb’s sunshield, a damaged transducer, and loose screws. With Roman, engineers so far have found no “significant surprises,” Townsend said.
“What we always hope for during this final round of environmental tests is that you’ve exercised the hardware at lower assembly levels, and it looks like, in Roman’s case, we did an exceptional job at those lower levels,” she said.
With Roman now fully assembled, attention at Goddard will shift to an end-to-end functional test of the observatory early next year, followed by electromagnetic interference testing and another series of acoustic and vibration tests. Then, likely around June, NASA will ship the observatory to Kennedy Space Center in Florida to prepare it for launch on a SpaceX Falcon Heavy rocket.
“We’re really into the final stretch of environmental testing for the system,” Townsend said. “It’s already been exposed to the harshest environments it will see until launch.”
