ABL Space Systems X-63

The Air Force Research Lab (AFRL) has a program called ARMR (Affordable Responsive Modular Rocket), under which a number of new technologies are to be evaluated and verified, which are intended to make future rocket propulsion development faster and cheaper. The most ambitious part of ARMR is ARISE (Aerospike Rocket Integration and Suborbital Experiment). The objectives of ARISE include the demonstration of a modular approach to rocket engine design and construction, as well as building and flight-testing an aerospike engine nozzle in all relevant flight regimes during a sub-orbital flight.

In December 2019, two contractors received contracts to build and fly a demonstrator rocket for ARISE - ABL Space Systems, and a team lead by Invocon, Inc. The original contracts ran for three years, so that the rockets should have made their first flights by the end of 2022. In April 2022, the official MDS designation X-63A was assigned to the ABL Space Systems vehicle, while the Invocon rocket became the X-64A.

Image: AFRL		Photo: ABL Space Systems
Left: X-64A, Right: X-63A		RS1 Block 1

The X-63A was called RS1A by ABL Space Systems, and consisted basically of the first stage core of ABL's RS1 2-stage orbital rocket design. The RS1 itself had been in development since ABL Space Systems was founded in 2017, with the focus on providing a simple and cost-effective easy-to-produce and easy-to-launch small-satellite launcher. However, in the end it never made a successful flight. After some delays, an initial launch was attempted in January 2023, but it failed only 10 seconds into flight, when a malfunction caused the shutdown of the first-stage engines. ABL then decided to move on with the development of an improved "Block 2" variant of RS1 with increased thrust and more propellant. However, a flight-ready RS1 Block 2 rocket was irrepairably damaged in a fire during a static test firing in July 2024. In early 2025, ABL Space Systems renamed itself as Long Wall, abandoning the commercial launch market and concentrating on missile defense. It can therefore be assumed that the X-63A program has been cancelled.

Specifications

Detailed physical characteristics of the X-63A are not available.

Main Sources

[1] AFRL: ARISE and Fly
[2] AFRL: AFRL's Rocket Lab Past, Present and Future
[3] Wright-Patternson AFB: AFRL awards agreements under Aerospike Rocket Integration and Sub-orbital Experiment (ARISE) program
[4] ABL Space Systems Website
[5] Wikipedia: ABL Space Systems

Back to Directory of U.S. Military Rockets and Missiles, Appendix 4

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Last Updated: 17 December 2025