This article is based on an official press release from NASA.

NASA Bolsters Supersonic Research Fleet with Retired Air Force F-15s

NASA has officially expanded its flight research capabilities by acquiring two retired F-15 Eagle aircraft from the U.S. Air Force. According to an official announcement from the agency, the jets arrived at NASA’s Armstrong Flight Research Center in Edwards, California, on December 22, 2025. These Military-Aircraft are slated to play a critical role in supporting the agency’s ongoing supersonic flight research, specifically the X-59 Quesst mission.

The transfer involves aircraft previously assigned to the Oregon Air National Guard’s 173rd Fighter Wing, based at Kingsley Field in Klamath Falls, Oregon. Rather than being sent to long-term storage, these high-performance jets have been redirected to support civil aviation research. NASA officials confirmed that the acquisition is part of a strategic effort to maintain a robust fleet capable of keeping pace with next-generation experimental aircraft.

The primary objective for these newly acquired assets is to support the X-59 Quesst (Quiet SuperSonic Technology) demonstrator. As the X-59 prepares for high-speed trials, the F-15s will serve as “chase planes,” providing essential visual verification and data collection during supersonic flight tests.

Operational Strategy: One to Fly, One for Parts

In a move designed to ensure long-term sustainability for the program, NASA revealed that the two aircraft will serve different functions. One of the F-15s will be modified to become an active research platform, joining the flight line at Armstrong. The second aircraft will be utilized as a “parts bird,” effectively serving as a donor airframe to provide spare components to keep the flying aircraft operational.

This logistical strategy addresses the challenge of maintaining older military airframes. By securing a dedicated source of spare parts immediately, NASA ensures that the active chase plane can remain flight-worthy throughout the duration of the X-59 program without facing supply chain delays common to legacy aircraft.

Role as a Chase Plane

The active F-15 will act as a chase plane, a vital component of flight testing. Chase planes fly in close formation with experimental aircraft to monitor safety, verify the operation of control surfaces, and capture high-resolution imagery. For the X-59 mission, the chase plane must match the experimental jet’s speed and altitude capabilities.

Troy Asher, Director for Flight Operations at NASA Armstrong, emphasized the importance of this Acquisitions in the official release:

“These two aircraft will enable successful data collection and chase plane capabilities for the X-59 through the life of the Low Boom Flight Demonstrator project.”

, Troy Asher, Director for Flight Operations at NASA Armstrong

Supporting the X-59 Quesst Mission

The timing of this acquisition aligns with critical milestones for the X-59 Quesst mission. The X-59 is designed to fly at supersonic speeds while generating a quiet “thump” rather than a disruptive sonic boom. Validating this technology requires a chase aircraft capable of sustained supersonic flight.

According to mission data, the X-59 completed its first flight on October 28, 2025, validating its subsonic airworthiness. The program is currently undergoing planned maintenance, with supersonic flight testing scheduled to begin in March 2026. The F-15, with a top speed exceeding Mach 2.5 (approximately 1,650 mph), is one of the few platforms capable of keeping up with the X-59 during these high-speed envelope expansion flights.

Technical Capabilities

NASA has a long history of utilizing the F-15 Eagle, dating back to the 1970s. The aircraft is favored for its robust airframe, twin-engine reliability, and high service ceiling of over 60,000 feet. The specific aircraft acquired are expected to be modified with research instrumentation, potentially including air-to-air schlieren photography equipment to visualize shockwaves.

“NASA has been flying F-15s since some of the earliest models came out… The F-15s allow NASA to operate in high-speed, high-altitude flight-testing environments.”

, Troy Asher, Director for Flight Operations at NASA Armstrong

AirPro News Analysis

Strategic Asset Management: We view this acquisition as a prime example of government efficiency through asset “upcycling.” The 173rd Fighter Wing is currently retiring its F-15 fleet as part of a broader Air Force transition. By transferring these assets to NASA rather than sending them to the “boneyard” (the Aerospace Maintenance and Regeneration Group in Arizona), the government extends the return on investment for these airframes.

Furthermore, the “parts bird” strategy suggests that NASA is preparing for an intensive flight schedule in 2026. As the X-59 moves toward community overflight testing to gather data for regulators, the reliability of the support fleet will be just as critical as the experimental aircraft itself. Without a reliable supersonic chase plane, the X-59 cannot safely push the boundaries of quiet supersonic travel.

Sources

• NASA: NASA Adds Two F-15 Aircraft to Support Supersonic Flight Research