Swift thinking buys NASA observatory a little more time before re-entry

NASA halted most science operations on the Swift observatory, and updated re-entry forecasts now place the descent past the point of no return at the end of summer rather than the start. The latest forecasts indicate Swift will drop below the critical 300 km altitude in September instead of July, improving chances for rescue because higher altitude increases survival likelihood. Forecast updates became more frequent once Swift entered the two-year window before re-entry. Changes in 2024, including solar maximum conditions and atmospheric expansion, increased drag and worsened outlooks, with many forecasts pointing to re-entry by summer 2026. Weekly forecasts guided the decision to pause science operations and will be critical for predicting Swift’s location when a reboost mission is launched.

"NASA's decision to halt most science operations on its Swift observatory has paid off. Estimates now put the spacecraft's descent past the point of no return to the end of summer rather than the start. The space agency presented the latest set of re-entry forecasts for the spacecraft, which now point to a descent below the critical altitude of 300 km (185 miles) in September rather than July. The figure is important, since the higher the spacecraft is, the better the chances of a successful rescue mission."

"Scientists continually update forecasts for the orbital decay of spacecraft. Once a mission is within two years of re-entry, those forecasts are updated more frequently. In November 2023, forecasts suggested Swift was entering that two-year window. Others estimated it would remain in orbit well into the 2030s. However, the outlook changed in 2024 as the Sun reached its solar maximum phase and Earth's atmosphere expanded slightly, increasing drag on Swift."

"By 2025, the picture was less rosy, with most forecasts estimating the observatory would re-enter by summer 2026. NASA put out a call to industry for a solution, eventually awarding the contract to Katalyst. The forecasts eventually became weekly and were key to deciding when to halt most science operations aboard the spacecraft. They will be equally critical in predicting where Swift will be when the reboost mission is launched."

""These predictions evolve, based on space weather forecasts and other factors like Swift's current height and orientation. It's also an iterative process with members of Swift's operations team. They determine new ways to point the spacecraft to reduce drag, and we do some new computations to see how much extra time that buys them.""

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