In its first mission since 2021, a Northrop Grumman Pegasus XL rocket is scheduled to be air-launched from the Lockheed L-1011 TriStar Stargazer. Driving aboard Pegasus XL is NASA’s Swift Increase Mission, a mission using a robotic servicing spacecraft from Katalyst House Applied sciences to lift, or “enhance,” the orbital altitude of NASA’s Neil Gehrels Swift Observatory.
Pegasus XL is scheduled to be dropped from Stargazer on Tuesday, June 30, at 10:23 UTC over the South Pacific Ocean. Stargazer will take off from the Ronald Reagan Ballistic Missile Protection Take a look at Web site at Kwajalein Atoll within the Marshall Islands. The rocket will ignite its strong motor 5 seconds after dropping from Stargazer.
NASA’s Swift Observatory and orbital decay
Launched in November 2004 atop a Delta II rocket from Florida, NASA’s Neil Gehrels Swift Observatory, generally often called Swift, is an area telescope designed to look at gamma-ray bursts and the X-ray, ultraviolet, and visible-light afterglows they produce. Gamma-ray bursts are the brightest and most energetic explosions within the universe and may final wherever from milliseconds to hours. The bursts are thought to originate mostly from supernovae, the explosions of high-mass stars on the finish of their lives.
A Delta II launches Swift in November 2004. (Credit score: NASA)
A successor to NASA’s Compton Gamma Ray Observatory, which operated from 1991 to 2000, Swift incorporates a gamma-ray burst detection price of 100 per yr and has greater than double the detection sensitivity of Compton.
When launched, Swift was anticipated to function for 2 years and research solely gamma-ray bursts. Nonetheless, with the spacecraft persevering with to function in good situation after 2006, NASA groups continued to help the mission and alter its scientific scope to incorporate observations of all astrophysical transient occasions throughout a number of wavelengths.
Swift detected its five hundredth gamma-ray burst in Might 2010, after which its 1,000th in October 2015. As of publication, Swift has detected 1,760 gamma-ray bursts, having detected 11 in 2026 alone.
When Swift was launched in 2004, Delta II inserted it right into a round low-Earth orbit (LEO) with a perigee altitude (the bottom level in its orbit) of 585 km and an apogee altitude (the very best level in its orbit) of 604 km at an inclination of 20.60 levels. Nonetheless, whereas LEO is technically above the Karman Line, the very outer areas of Earth’s ambiance nonetheless permeate into the orbital area of LEO. Thus, spacecraft travelling at these altitudes can work together with the ambiance and have their orbits degraded by atmospheric drag.
Swift, being situated in LEO, has seen vital orbital degradation because of atmospheric drag. Over the 21 years it’s been working in LEO, Swift’s perigee altitude has lowered to 373 km and its apogee altitude to 378 km. The Worldwide House Station, situated in a 413 km by 422 km LEO, faces the identical difficulty and makes use of visiting cargo and crewed spacecraft to lift its orbital altitude to stop re-entry into Earth’s ambiance. The House Shuttles did the identical for the Hubble House Telescope throughout their servicing missions to the observatory.
Nonetheless, Swift sees no visiting automobiles to spice up its orbit, which has decayed extra rapidly than anticipated because of elevated photo voltaic exercise over the previous couple of years. With out an orbital enhance, Swift has a 90% probability of reentering Earth’s ambiance earlier than the tip of 2026. With the spacecraft in operable situation and persevering with to return helpful scientific information, NASA turned to the personal spaceflight sector for choices to avoid wasting the telescope.
Artist’s rendering of NASA’s Neil Gehrels Swift Observatory. (Credit score: NASA/Chris Smith)
Swift Increase Mission and Katalyst’s LINK spacecraft
Below the company’s Small Enterprise Innovation Analysis program, NASA awarded Katalyst House Applied sciences a $30 million contract in September 2025 to develop a spacecraft able to boosting Swift’s orbit. Whereas the mission’s main aim is to spice up the orbit of Swift, the mission may also function a expertise demonstration for future missions that might service and “save” scientifically vital space-based missions.
“Given how rapidly Swift’s orbit is decaying, we’re in a race in opposition to the clock, however by leveraging business applied sciences which can be already in growth, we’re assembly this problem head-on. This can be a forward-leaning, risk-tolerant strategy for NASA. However trying an orbit enhance is each extra inexpensive than changing Swift’s capabilities with a brand new mission, and helpful to the nation — increasing using satellite tv for pc servicing to a brand new and broader class of spacecraft,” mentioned Shawn Domagal-Goldman, Director of NASA’s Astrophysics Division, within the September 2025 press launch.
On the time of its choice by NASA, Katalyst was already creating robotic servicing spacecraft with an anticipated demonstration mission in 2026. The Swift Increase Mission will function an illustration mission for the corporate’s upcoming NEXUS servicing spacecraft, which shall be able to servicing a number of spacecraft throughout a number of completely different orbits. In line with NASA, the mission will “be the primary time a business robotic spacecraft captures a authorities satellite tv for pc that’s uncrewed, or not initially designed to be serviced in house.”
For the Swift Increase Mission, Katalyst will use its LINK servicing spacecraft to rendezvous with, examine, dock with, and enhance Swift. LINK’s growth was vastly accelerated after the mission contract was awarded, with the spacecraft finishing environmental testing in Might 2026, simply eight months later.
LINK will use three parallel-manipulator robotic arms to work together with Swift, with every of the three arms that includes a lidar sensor and grippers. The spacecraft shall be able to capturing and conducting the mission with only one arm, however will use all three for higher management. Provided that Swift was not designed with a docking port for servicing, LINK will use ground-handling flanges on Swift’s satellite tv for pc bus to “dock” to the spacecraft. Forward of docking, the 2 spacecraft will coordinate their attitudes so LINK can visually examine the docking factors and guarantee they aren’t obstructed.
The precise docking process that LINK will observe was examined and validated on an air-bearing desk utilizing a mock mannequin of Swift. LINK has the flexibility to abort a docking try and retry.
For the enhance itself, LINK is supplied with three Corridor-effect thrusters that make the most of xenon gas and 16 response management system thrusters. Every of the Corridor-effect thrusters is angled to align with the middle of mass of LINK and Swift when docked. Following the enhance — which, if profitable, will return Swift to its authentic near-600 km LEO — LINK will undock, deorbit, and reenter Earth’s ambiance.
LINK built-in with Pegasus XL forward of fairing encapsulation. (Credit score: NASA/Ron Beard)
Northrop Grumman’s Pegasus XL rocket was chosen because the launch automobile for LINK because of its capability to launch the spacecraft into Swift’s distinctive 20.6-degree orbit inclination. Pegasus XL is a three-stage small-lift launch automobile that’s air-launched horizontally from the Lockheed L-1011 TriStar Stargazer. The rocket’s first three phases make the most of strong propellants, with an Orion 50SXL as the primary stage, an Orion 50XL because the second stage, and an Orion 38 because the third stage.
Pegasus XL is a extra highly effective variant of the unique Pegasus rocket, which first launched in April 1990. Over its profession, Pegasus and Pegasus XL have launched 45 missions, with 40 successes, three failures, and two partial failures. Pegasus XL stands 17.6 m tall with a diameter of 1.28 m, and is able to launching 450 kg to a 200 km LEO.
Pegasus XL was mated to Stargazer at NASA’s Wallops Flight Facility on June 12, with LINK arriving at Wallops on June 5 and Pegasus XL integration accomplished on June 9. Stargazer and Pegasus XL departed Wallops for Kwajalein Atoll within the Marshall Islands on June 18.
On launch day, Stargazer and Pegasus XL, with the LINK spacecraft encapsulated inside its fairing, will depart from the Ronald Reagan Ballistic Missile Protection Take a look at Web site at Kwajalein Atoll. After cruising over the South Pacific, Pegasus XL shall be launched from Stargazer at 10:23 UTC on Tuesday, June 30. After falling away from Stargazer for 5 seconds, Pegasus XL will ignite its first stage, starting the Swift Increase Mission.
Pegasus XL is launched from Stargazer on a earlier mission. (Credit score: NASA)
At T+01:19 minutes, the primary stage will burn out and separate, with the second stage igniting at T+01:35 minutes. The second stage will burn for over a minute, with burnout and separation occurring at T+02:50 minutes. Fairing separation is predicted in the course of the second stage burn at T+02:17 minutes. Pegasus XL will then coast for a number of minutes, igniting its third stage at T+06:35 minutes. Third stage burnout is predicted at T+07:44 minutes, with LINK deployment at T+12:44 minutes.
LINK checkouts will start instantly following deployment and final for 2 weeks. The spacecraft will then spend two to a few weeks rendezvousing and inspecting Swift, earlier than spending one other one to 2 weeks docking with the telescope. The enhance section of the mission is predicted to final round three months, with the recommissioning of Swift after the enhance taking round a month to finish.
The Swift Increase Mission will mark the forty sixth and presumably closing mission for the Pegasus XL rocket. The mission may also mark the rocket’s first because the Odyssey (TacRL-2) mission in June 2021, and the 156th total orbital launch try in 2026.
(Lead picture: Pegasus XL mated to Stargazer forward of the Swift Increase Mission. Credit score: Micah Pieczarka for NSF)
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