Pegasus and Atlas: The end of two eras
Two launches on consecutive days last week marked milestones that, taken together, say a great deal about the transition under way in the launch industry.
On July 2, United Launch Alliance launched the final Atlas 5 mission purchased by Amazon Leo for its low Earth orbit broadband constellation, closing one of the most important commercial launch campaigns in the rocket's history. A day later, Northrop Grumman's Pegasus XL air-launched rocket successfully deployed a spacecraft that will attempt to extend the life of an operational NASA vehicle.
The missions had little in common operationally. But each represented the end of one chapter and the beginning of another.
For Pegasus, the July 3 launch from Kwajalein Atoll could prove to be its last. Developed by Orbital Sciences — now part of Northrop Grumman — and first flown in 1990, Pegasus became the world's first privately developed orbital launch vehicle and the first operational rocket launched from an aircraft. Over 46 missions, a modified L-1011 carrier aircraft carried the winged rocket to about 40,000 feet before releasing it for ignition.
The Swift Boost mission deployed a robotic servicing spacecraft built by Katalyst Space Technologies. Its assignment is to rendezvous with NASA's Neil Gehrels Swift Observatory, capture it and raise it into a higher orbit.
Swift, launched in 2004 to study gamma-ray bursts and other high-energy astrophysical phenomena, remains scientifically productive. But increasing atmospheric drag caused by heightened solar activity is slowly pulling the spacecraft toward reentry. Because Swift has no propulsion system, NASA faced a choice: replace a functioning observatory or attempt to save it.
The agency chose the latter, concluding that a roughly $30 million servicing mission was significantly less expensive than building a replacement spacecraft.
The changing launch economics
When it entered service, Pegasus offered capabilities few others could match. Air launch eliminated dependence on fixed launch pads, allowed access to a broad range of orbital inclinations and provided scheduling flexibility that appealed to government science missions.
Over time, however, those advantages became less compelling.
As satellites became smaller and cheaper, many customers opted to fly as rideshare payloads rather than purchase dedicated launches. At the same time, Rocket Lab, Firefly Aerospace and other companies entered the small-launch market, while SpaceX's Falcon 9 rideshare program dramatically lowered the cost of reaching orbit.
Pegasus also carried structural disadvantages. Maintaining a dedicated L-1011 carrier aircraft, specialized crews and supporting infrastructure made economic sense when the rocket flew regularly. As launch cadence slowed, those fixed costs became increasingly difficult to justify.
Northrop Grumman has stopped short of declaring Pegasus retired. Company officials have said they would consider flying it again if customers determined that an air-launched orbital capability had value for tactically responsive space missions. Commercially, however, Pegasus no longer competes in the market it helped create.
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