Tag: Gehrels Swift

Katalyst completes final ground testing of its Swift rescue spacecraft

8:01 am

Katalyst's proposed Swift rescue mission
Katalyst’s proposed Swift rescue mission.
Click for original image.

The orbital servicing startup Katalyst has now successfully completed the final ground testing of its Swift rescue spacecraft, dubbed LINK, that it hopes will be able to catch the Gehrels-Swift Telescope and raise its orbit, thus saving the telescope.

During vibration testing at NASA Goddard, engineers mimicked the shaking the spacecraft will experience during its launch from a Northrop Grumman Pegasus rocket. In the footsteps of Swift itself and NASA’s upcoming Nancy Grace Roman Space Telescope, the Katalyst team also used NASA Goddard’s Space Environment Simulator for thermal vacuum testing.

Once the air was pumped out of this 27-foot-wide chamber, LINK experienced space-like hot and cold temperature extremes. The team also practiced firing the satellite’s three xenon-powered ion thrusters and deployed one of the arms.

After some more testing in Arizona, the spacecraft will be integrated in June onto Northrop Grumman’s Pegasus rocket — the last one in its inventory — and launched later that month.

Katalyst has never done this before. It was preparing LINK as a demo mission when NASA requested bids for saving Swift. It proposed reconfiguring LINK for that purpose, and won the contract in September 2025, only eight months ago.

If this mission succeeds it will be a big feather in Katalyst’s cap.

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Final ground testing begins of Katalyst’s Swift rescue spacecraft

5:46 am

Katalyst's proposed Swift rescue mission
Katalyst’s proposed Swift rescue mission.
Click for original image.

Only seven months after NASA awarded the satellite repair startup Katalyst the contract to save the Gehrels-Swift space telescope, the company has delivered the completed LINK spacecraft to the Goddard Space Flight Center in Maryland for final ground testing.

Katalyst will move forward with LINK’s vibration and thermal tests using NASA Goddard’s in-house facilities in the coming weeks before installation into Northrop Grumman’s Pegasus rocket at the agency’s Wallops Flight Facility in Virginia.

Gehrels-Swift has been one of NASA’s most productive space telescopes. Unfortunately its orbit is decaying and if nothing is done to raise that orbit it will burn up in the atmosphere in 2029 or so. To extend this timeline engineers have stopped almost all science work in February.

Katalyst hopes to launch LINK as soon as later this year. It was able to get it built so quickly because it was already under construction as the company’s first demo of its repair technology. When NASA put out a bid for boosting Swift, the company shifted gears and reconfigured LINK for this mission.

If successfully, the achievement will be a major coup for this startup.

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Astronomers detect the first comet whose nucleus’ reversed its rotation

11:28 am

Astronomers using data collected by the orbiting Gehrels Swift and Hubble space telescopes now think the nucleus of a small comet reversed its rotation sometime in 2017, caused by the force of the material sublimated off its surface.

From the abstract of their paper [pdf]:

The rotations of cometary nuclei are known to change in response to outgassing torques. The nucleus of the Jupiter-family comet 41P/Tuttle–Giacobini–Kresak exhibited particularly dramatic rotational changes when near perihelion in 2017 April. Here, we use archival Hubble Space Telescope observations from 2017 December to study the postperihelion lightcurve of the nucleus and to assess the nucleus size.

From both Hubble photometry and nongravitational acceleration measurements, we find a diminutive nucleus with effective radius 500 ± 100 meters. Systematic optical variations are consistent with a two-peaked (i.e., rotationally symmetric) lightcurve with period 0.60 ± 0.01 days, substantially different from periods measured earlier in 2017. The spin of the nucleus likely reversed between perihelion in 2017 April and December as a result of the outgassing torque.

In plain English: the thrust of the material being thrown from the surface as the comet made its close approach to the Sun was sufficient to slow and then reverse the nucleus’s rotation. This process was helped by the relatively small size of the nucleus compared to the material being sublimated from it.

The data also suggests the nucleus was once much larger, and has been whittled down to its present small size as it made its multiple close fly-bys of the Sun during the past 1,500 years. Rather than break-up, as most comets do at some point as their nucleus gets smaller, this comet’s nucleus simply kept shrinking, to the point that the thrust of that material could change its rotation.

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Two companies to study ways for extending the life of the Gehrels Swift space telescope

9:15 am

NASA yesterday announced that it has awarded two companies, Cambrian Works in Virginia and Katalyst Space Technologies in Arizona, each $150K study contracts for reviewing whether it makes sense to send a robotic servicing mission to Gehrels Swift space telescope to raise its orbit and extend its life.

Since its launch in 2004, NASA’s Swift mission has led the agency’s fleet of space telescopes in investigating changes in the high-energy universe. The spacecraft’s low Earth orbit has been decaying gradually, which happens to most satellites over time. Because of recent increases in the Sun’s activity, however, Swift is experiencing additional atmospheric drag, speeding up its orbital decay. This lowering orbit presents an opportunity for NASA to advance a U.S. industry capability, while potentially extending the science lifetime of the Swift mission. The concept studies will help determine whether extending Swift’s critical scientific capabilities would be more cost-effective than replacing those capabilities with a new observatory.

According to this paper [pdf], the telescope’s orbit will decay before the end of 2029, so speed is of the essence. Why NASA is thus spending time and money on a “study” contract from companies that don’t do orbital servicing or have orbital tugs is very curious. Wouldn’t make more sense to request bids from the many orbital servicing and tug companies that now exist (D-Orbit, Astroscale, Northrop Grumman, Firefly, Blue Origin, Rocket Lab, Impulse) to see if any can do the job at a reasonable cost and are willing?

Gehrels Swift has proven to be one of the most valuable and useful high energy space telescopes ever launched. First of all its cost was relatively low. Second, it is designed to quickly observe a gamma ray burst (GRB) location in multiple other wavelengths (optical especially). That ability helped solve the mystery of GRBs, as well as numerous other high energy events. It would be a tragedy to lose it.

It would also be far more expensive to build a replacement.

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Gehrels-Swift returns to science operations

2:13 pm

The Gehrels-Swift orbiting space telescope has returned to full science operations, after engineers determined the shut down on January 18th was caused by the failure of one reaction wheel and uploaded software allowing the telescope to function using only its remaining five gyroscopes.

In the last two decades satellite engineers have developed a range of software to allow spacecraft to point with acceptable accuracy using as few as two gyroscopes, even one in some circumstances. Thus, Gehrels-Swift has significant margin with five working reaction wheels.

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Engineers determine failed gyroscope caused Gehrels-Swift shutdown

1:56 pm

Engineers have now determined that the failure of one of the six reaction wheels that point the orbiting Gehrels-Swift Observatory was the cause of its shutdown into safe mode on January 18th, and are now reconfiguring the space telescope to operate with only five gyroscopes.

The team is currently testing the settings for operating the spacecraft using the five operational reaction wheels. After the tests for these settings have been completed, they plan to upload them to the spacecraft next week.

Swift can fully carry out its science mission with five wheels. After careful analysis, the team has determined that the five-wheel configuration will minimally impact the movements necessary for Swift to make science observations. The team expects the change will slightly delay the spacecraft’s initial response time when responding to onboard gamma-ray burst triggers, but this will not impact Swift’s ability to make these observations and meet its original operational requirements.

Only after getting Gehrels-Swift operating again will the engineers then consider trying to recover the failed reaction wheel.

Gehrels-Swift was one of the key space telescopes that made it possible for astronomers to solve the mystery of gamma ray bursts. It is also used today to help identify the source of mysteries like fast radio bursts and other supernovae events. It was designed to quickly begin observing in multiple wavelengths any spot in the sky where a mystery burst or new supernova has occurred, thus getting astronomers the earliest new data possible.

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NASA renames Swift telescope to honor Neil Gehrels

10:48 am

NASA has renamed the Swift space telescope, designed to quickly detect and observe fast transient events in space like gamma ray bursts, to honor the late Neil Gehrels, the man who led the project from day one.

During a presentation at a NASA town hall meeting at the 231st Meeting of the American Astronomical Society here, Thomas Zurbuchen, NASA associate administrator for science, said that Swift would now be known as the Neil Gehrels Swift Observatory.

Gehrels, who died in February 2017, had been principal investigator for Swift, a mission launched in 2004. The spacecraft was designed to be able to rapidly respond to transient events, such as gamma-ray bursts, observing them at wavelengths ranging from gamma rays to visible light.

“Neil wore many hats in service to the astrophysics community,” said Paul Hertz, director of NASA’s astrophysics division, at a later press conference at the meeting. In addition to being the principal investigator for Swift, had served as project scientist on the Compton Gamma-Ray Observatory and Fermi missions. At the time of his death last year he was project scientist for the Wide-Field Infrared Survey Telescope, NASA’s next flagship astronomy mission after the James Webb Space Telescope.

Knowing astronomers, they will now refer to this observatory as the NGSO. Not I. It will be “Gehrels Swift” to me, whenever I need to mention it. Gehrels was one of the most friendly, open, and easy-to-work-with astronomers I ever had to deal with. He is sorely missed.

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