NASA's Swift Observatory Rescue Mission: A Bold Leap in Space Servicing

Despite everything that US government bodies have faced under the Trump administration, from budget cuts to blocked websites, NASA's still good for innovation.

Not only is it aiming to rescue a two-decade-old space-based telescope with an emergency mission designed and developed in about a year, but it will also launch that mission from the belly of an airplane.

Packed into a Pegasus XL rocket — the world's only airborne-launched rocket — a robotic spacecraft called LINK is supposed to boost the Neil Gehrels Swift Observatory back into its orbit.

The Swift Observatory is a "unique telescope that has reinvented itself over the years," wrote Brad Cenko, Swift's Principal Investigator at NASA, in an email to DW.

"This mission is a great opportunity for NASA to try something novel, with real positive scientific benefit," said Cenko.

As it's the first time this has ever been attempted, the mission may fail. But if NASA doesn't even try to save Swift, the telescope will re-enter Earth's atmosphere — in an uncontrolled way — by the end of this year.

Why save the Neil Gehrels Swift Observatory?

The short answer is that NASA wants to save Swift "for science," said Cenko. But it's also to save money.

"While it would certainly be possible to build a new and improved Swift, the cost would be much larger than the cost for the boost, which is $30m (€26m), including the launch. Swift cost about $250m to build and launch in 2026 dollars," said Cenko. "So, this could be quite a bargain."

Swift was designed to study gamma-ray bursts. It was launched in 2004.

Gamma-ray bursts are a by-product of powerful explosions in the universe, released for instance when stars explode or celestial objects collide.

Those explosions and collisions can create particular chemical elements. And scientists say that by studying gamma rays, they can deduct how certain chemicals form.

"[Swift] has been extremely successful in this regard, detecting over 2,000 of these sources all the way out to the edge of the visible universe, and helping confirm that most of the heaviest elements in the periodic table, like the gold and platinum in our jewelry, are forged in these systems," Cenko said.

In its more than 20 years of operation, Swift has adapted into an "astrophysics multitool" that now surveys radiation in the visible, ultraviolet, X-ray, and gamma-ray parts of the spectrum.

"The universe is an incredibly dynamic place," said Cenko, "somewhere in the cosmos a massive star explodes every second. Hubble takes at least 1-2 days to repoint at a target of interest. Swift routinely conducts follow-up of things that go bump in the night within minutes. It is NASA's first responder."

Originally launched into an orbit about 600 kilometers (370 miles) above Earth's surface — higher than the average orbit of the International Space Station — Swift has since lost more than 220 kilometers of altitude. Experts think this is likely due to increased activity on the sun, like solar flares, which can create extra drag on spacecraft circling the Earth, causing orbits to decay.

Robotic servicing: How LINK will boost Swift

The central piece in the Swift Boost Mission is a robotic servicing spacecraft known as LINK. It was made by a commercial company in the US called Katalyst Space.

Because Swift is falling so fast, the firm only had a year to design, build, test — and now launch — the spacecraft.

LINK will launch from a Northrup Grumman Stargazer L-1011 aircraft in a small Pegasus rocket that measures 17.6 meters (less than 57 feet) in length.

Launching from Kwajalein Atoll in the Marshall Islands, it will be lifted to about 40,000 feet over an open area of ocean and then released into a five-second freefall before the rocket ignites the first of three motor stages.

Once LINK is released from the rocket in space, Katalyst will need to establish a signal between it and ground control, then perform tests for a few weeks before moving the servicing spacecraft towards Swift.

It could then take another month before LINK latches onto Swift, because the telescope was not designed with docking ports or grappling fixtures. NASA compares the difficulty of the maneuver to landing on an asteroid.

If the attempt to dock with Swift is successful, LINK will fire three electric propulsion thrusters to raise the telescope over a period of several more months.

This is all new technology in an area known as on-orbit servicing (OOS) in the US and in-space operations and servicing (ISOS) in Europe.

"There are broad commercial and defense applications for robotic servicing," said Cenko, referring to a trend towards dual-use technologies in space — technologies for civilian and military use.

If the orbit-boosting mission goes as planned, Swift will resume science operations until its planned end of operation in 2030.

Europe's eyes on in-space operations and servicing

The European Space Agency is also working on dual-use in-space operations and servicing technology. And – similar to NASA – ESA says the focus helps support its domestic commercial space industry.

"We are working on a portfolio of technologies for rendezvous and capture," said Berengere Houdou, Head of ESA's Space Safety Missions Office. "For example, space sensors and image processing algorithms for autonomous navigation to know the position of a target satellite and robotic arms to seize and secure it."

Houdou said these technologies were required for the next era of operations in space, and that "there are indeed synergies with dual use applications."

Edited by: Derrick Williams