NASA's Swift telescope falls to Earth on Wednesday after rescue attempt fails

The telescope launched in 2000 on a two-year prime mission to study the origin of gamma-ray bursts. It kept working for almost 22 years. On Wednesday it comes back down.

NASA's Swift Observatory should re-enter Earth's atmosphere at about 3:30AM ET on Wednesday, with a margin of about 11 hours either way, according to The Verge's report on 3 November. The agency expects most of the spacecraft to burn up. Some components, though, will likely survive re-entry and reach the surface.

The numbers NASA has published are not alarming. Swift weighs around 3,200 pounds and measures 5.6 meters (18.4 feet) high and 5.4 meters (17.7 feet) wide, much of the latter made up of its deployable solar arrays. The observatory's low orbital inclination limits where debris can fall. Any surviving fragments can only come down between 20.6 degrees south latitude and 20.6 degrees north latitude. The agency puts the risk of harm to anyone on Earth at roughly 1 in 2,100.

That figure is the one piece of the story worth reading slowly. A 1 in 2,100 chance sounds small until you remember it is a per-re-entry number attached to a single object. The object is a truck-sized piece of hardware that was never designed to come home in one piece. NASA's own statement, quoted by The Verge, is careful: re-entry locations "can vary from hemisphere to hemisphere and depend on when it re-enters."

"The risk of harm coming to anyone on Earth is unlikely, approximately 1 in 2,100. NASA and Space Force will continue to monitor the re-entry and update predictions."

The agency gave up on saving the telescope earlier this year. The Link spacecraft attempting the rescue ran into technical problems with attitude control. That is the part of the story that reads like an ending rather than an accident. Nobody lost control of Swift in a dramatic failure. A repair mission was sent. The repair mission did not work. The orbit kept decaying until the only remaining question was where the debris lands.

What Swift was actually for

Swift was built to chase gamma-ray bursts, the most energetic explosions in the universe. It did that job well enough to outlast its design life by two decades. As The Verge notes, it went on to serve as a general-purpose multi-wavelength observatory long after its prime mission ended. Solar storms eventually pushed it into a lower orbit. That is how a working science platform becomes a re-entry prediction.

The wider picture is that this is a normal end for a low-Earth-orbit satellite, not an anomaly. NASA is tracking the descent and says it will update predictions, and the Space Force is monitoring alongside it. Readers who want to follow the timeline can watch NASA's blog for continuing updates.

Space.com reported on 3 November that the agency's planetary defense work relies on military and civilian satellites watching fireballs and meteors to keep track of what enters the atmosphere. That is the same monitoring infrastructure that will be watching Swift come down, just pointed at a much larger and much better catalogued object.

Not the only thing falling, or flying

The same week brings a reminder that orbital infrastructure is a mix of the very old and the very new. Space.com marked 2 November as the anniversary of Expedition 1. NASA astronaut Bill Shepherd and cosmonauts Yuri Gidzenko and Sergei Krikalev arrived at the International Space Station in 2000 and began four and a half months of continuous occupation. Space.com notes that there has been a continuous astronaut presence aboard the station for 26 years since then. The first crew unpacked supplies and installed the station's first solar arrays.

The station got another hardware upgrade this week. Space.com reported on 29 October that astronauts deployed a new solar array during the 100th US spacewalk by ISS crew members, and ScienceDaily covered the same upgrade on 30 October. A robot cube called Astrobee, roughly the size of a toaster, is also still working aboard the station. The first two units arrived in 2019, seven years ago, according to Space.com's photo feature on 3 November.

Further out, Space.com reported on 3 November that the number of Starship refuelling flights needed for a crewed Artemis lunar landing remains unresolved. A Government Accountability Office audit in summer 2021 estimated up to 16 launches. A member of the Aerospace Safety Advisory Panel recently put the figure as high as 22, and Elon Musk posted on X that it would be closer to six or eight. The sources disagree, and nobody has published a settled number.

Science results that did not make the front page

For readers who came for mission science rather than re-entry arithmetic, there is a thinner but real set of results. The Smithsonian's National Air and Space Museum opened its final renovated spaceflight gallery, "At Home in Space," on 30 October, Ars Technica reported on 2 November. The opening capped seven years of work and nearly $1 billion in renovation. Curator Jennifer Levasseur described the gallery as the story of long-duration spaceflight, and said its centerpiece is the ISS.

"It's the prep story, the space shuttle story. It's what allows us to end up at a place where we have 25-plus years of long-duration spaceflight experience," Levasseur said.

The gallery includes a space shuttle main engine, the Robonaut 1A prototype humanoid robot, and what Levasseur said is the first and possibly only public display of a fully flown extravehicular mobility unit. The suit is missing a working portable life support system, because all the backpacks are still needed in service, according to Ars Technica.

On the commercial side, Rocket Lab launched a Japanese Earth-observing radar satellite on its 99th mission to date, Space.com reported on 2 November, and SpaceX flew 27 Starlink satellites from California on 31 October. The Air Force Research Laboratory confirmed on 26 October that it recovered cargo pods from SpaceX's Starfall capsule after a point-to-point delivery test, Space.com reported on 29 October. The pods carried sensors to measure temperature, shock and vibration through launch, reentry and splashdown.

None of that changes the arithmetic on Swift. The telescope is coming down on Wednesday, the risk estimate is 1 in 2,100, and the window runs to about 11 hours on either side. NASA and the Space Force will keep updating the prediction. That is the only useful thing anyone can do until the object is gone.