XL1 / XL1T

Under Development in Partnership with NASA CATALYST (SAAM ID 18250)

The Lunar CATALYST initiative is a public-private partnership that began in October 2015 with the competitive selection of three U.S. companies to partner with NASA via a “no funds exchanged” space act agreement with each company. The goal of the initiative is to encourage the development of robotic lunar landers that can be integrated with U.S. Commercial launch capabilities to deliver payloads to the lunar surface.

XL-1_LunarSurface - Moon.jpg

MSS is instituting an incremental development approach that is based upon evolving the existing MSS lander technology into two families of robotic landers. MSS’ robotic lander concepts are the XL and XEUS families of landers.


The first lander concept, the XL-1, is a small, single-use lander capable of placing a 100-kg payload on the lunar surface. The XL-1 is sized for launch as a secondary or ride-share payload on Falcon 9, Atlas V, or Delta IV launch vehicles. XL-1 uses Masten's MXP-351, a non-toxic storable hypergolic propellant system. The XL-1 is designed to offer a mission duration that is minimally sufficient to land on the lunar surface, transmit payload activation commands, and activate the payload release/deployment mechanism. The XL-1 vehicle will provide an opportunity to evaluate and improve common systems and technologies that are incorporated into XEUS.


XL-1_LunarOrbit - Moon.jpg

The implementing philosophy for the development of MSS’ lunar lander families is an iterative one, with each iteration conquering a new development area. Leveraging off of their vertical test bed heritage, Masten plans to build a terrestrial demonstrator (XL-1T) version of their XL-1 lunar lander as an initial step. This activity is intended to tackle four engine control authority, general risk reduction, and provide a tangible proof-of-concept for potential clients. All lessons learned from the design, build-up, and testing of the XL-1T will feed directly into the XL-1 vehicle. Masten will tackle formal space qualification of their systems for the XL-1 vehicle. The next development leap to the XEUS family of landers will have Masten conquering cryogenic propulsion with long duration storage, propulsion modules vs. a distributed system, and rotation of the vehicle for soft landing.


Notable contributions through the MSS and NASA partnership include:


  • Identifying and fast-tracking knowledge of a new hypergolic fuel combination with testing in less than nine months
  • Conducting stress, thermal, and fatigue analysis that accelerated design efforts by a factor of two
  • Training and migrating of MSS legacy flight software code to Core Flight Software (cFS), a current path forward for all MSS programs
  • Co-developing a new valve driver and distributed avionics architecture, accelerating MSS efforts over one year
  • Producing a hazard detection system (HDS) survivability report that allows MSS to quickly evaluate the current state of the art approaches and create a risk-cost matrix for use in future mission planning
  • Co-developing tools and systems to work with a geographically diverse team while maintaining MSS’ agility and core competencies


Activities on the horizon include joint manufacturing of the XL-1T vehicle, testing of the XL-1T vehicle, design refinement for the XL-1 vehicle, and development of qualification approaches for the XL-1 hardware.


Related Paper: "NASA Lander Technologies Project Status", AIAA SPACE 2016, AIAA SPACE Forum, (AIAA 2016-5221), Dr.Greg Chavers