NASA's Swift Observatory Falling Uncontrollably, Expected to Burn Up Within Days
NASA's Swift telescope is falling uncontrollably after a failed rescue boost. It will burn up in Earth's atmosphere within days, ending over 22 years of gamma-ray science.
The story in focus
NASA's Neil Gehrels Swift Observatory, launched in 2004, is falling uncontrollably and expected to burn up in Earth's atmosphere within days. A rescue boost attempt in late August failed due to technical issues. The telescope operated for over 22 years, far exceeding its two-year design.
- Swift is falling uncontrollably and will burn up in Earth's atmosphere within days.
- A spacecraft commissioned to boost Swift out of danger launched in early July, but technical issues made a boost attempt impossible by late August.
- Swift launched in 2004 for a two-year mission and operated for over 22 years.
- The observatory uniquely combined gamma-ray, X-ray, and ultraviolet/visible instruments to rapidly point at transient events.
- Swift participated in the 2017 neutron-star merger observation and the first neutrino traced to its origin.
Failed rescue and orbital decay
NASA's Neil Gehrels Swift Observatory is falling uncontrollably and is expected to burn up in Earth's atmosphere within days. A spacecraft commissioned by NASA to lift Swift out of danger launched in early July, but by late August technical issues made a boost attempt impossible.
Over its decades in orbit, Swift lost about half its original altitude as it repeatedly struck atmospheric molecules, which slowed it and pushed it closer to Earth. Relatively high solar activity in recent years accelerated the decay, preventing the spacecraft from continuing into the 2030s as engineers had hoped.
Gamma-ray burst science
Swift launched in 2004 to study gamma-ray bursts, the most powerful outbursts known, which often faded before earlier telescopes could respond. Its Burst Alert Telescope monitored up to half the visible sky for gamma rays and pinpointed their locations. The spacecraft could then rapidly swing its X-ray and ultraviolet/visible instruments to the same patch of sky, a combination unlike any observatory before or since.
Its observations confirmed that long bursts stem from exploding stars and short bursts from merging neutron stars, while also revealing bursts that did not cleanly fit that division. Swift recorded the brightest gamma-ray burst of all time, nicknamed BOAT, and the highest-energy photons from such a burst. All of its data was made public immediately, an approach credited with inspiring other observatory teams.
Collaborations and final observations
Swift participated in two back-to-back discoveries in 2017: the explosion caused by two neutron stars merging and the first neutrino traced back to its origin. In its later years, it observed between five and 10 targets of opportunity most days, supporting studies of a wide range of changing objects.
After the boost attempt was called off, the team turned Swift's instruments back on for final observations, including technical checks to ensure the utility of recent data, indirect observations of Earth's lower atmosphere, and glimpses of a comet. A particularly energetic gamma-ray burst in late September was among the last science targets. Nothing is lined up to replace Swift's unique capabilities.
Why did the rescue boost for Swift fail?
A spacecraft commissioned to raise Swift's orbit launched in early July, but by late August technical issues made a boost attempt impossible, leaving the telescope to fall uncontrollably and burn up.
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