Race against re-entry: Swift's would-be saviour straps itself to a rocket

NASA's sprint to save the Swift observatory has reached another milestone: Katalyst Space's LINK robotic servicing spacecraft is now installed atop its Pegasus XL launcher. The milestone came less than a year after the space agency awarded the rescue contract. The next step will be to attach the Pegasus XL to the Stargazer carrier aircraft (the last airworthy Lockheed L-1011 TriStar), which will carry it from NASA's Wallops facility to the Kwajalein Atoll in the South Pacific Ocean for launch. Launch is expected to occur later this month. The goal is to boost the Swift observatory, whose orbit is decaying faster than expected due to increased solar activity. Swift lacks thrusters to compensate for the problem, so a return to Earth in the coming months is inevitable without intervention. Engineers recently bought the vehicle a little extra time by orienting the spacecraft and reducing the science output, but there is precious little margin in the timelines. The mission is high-risk, and Swift has little to lose. However, if successful, the approach could extend the lifetimes of other craft, including the Hubble Space Telescope, which will also re-enter the atmosphere in the coming years without intervention. Although NASA rejected a proposal by its now administrator Jared Isaacman to reboost the observatory using a SpaceX Dragon spacecraft, if the mission to Swift is a success, the agency will have another, far less expensive, option to consider. Like Swift, Hubble's orbit is decaying, and there will come a point in the coming years when managers must decide whether to attempt to extend the life of the veteran observatory, devise a way of performing a controlled re-entry, or let nature take its course. Swift was one of the missions slated for the chopping block under proposed budget cuts, so a successful rescue would mark a remarkable turnaround. Extending spacecraft beyond their primary mission isn't unusual. ESA, for instance, just endorsed extensions for several veteran missions, including Mars Express, XMM-Newton, and SOHO. But a Swift-style orbital rescue is something altogether different, and one that operators of other spacecraft facing decaying orbits will be watching closely. (R)