SpaceX Plans for In-Space Refueling Test for Starship in Early 2025

SpaceX is gearing up to test a key technology that could be essential for future space exploration. As early as March 2025, the company aims to transfer propellant between two Starship vehicles in orbit, a pioneering step in spacecraft refueling. This milestone could help SpaceX and NASA achieve their shared goal of returning astronauts to the Moon under the Artemis program, a mission that’s planned to include a crewed lunar landing by September 2026.

The U.S. space agency awarded SpaceX a $4.05 billion contract to build two human-rated Starships, specifically designed for landing on the lunar surface. NASA views these vehicles as pivotal to the success of the Artemis program and the goal of establishing a sustainable human presence on the Moon. Kent Chojnacki, deputy manager of NASA’s Human Landing System (HLS) program, recently discussed how NASA and SpaceX are working closely to meet these ambitious targets.

SpaceX has already conducted a series of test launches, the most recent of which made history on October 13, when SpaceX successfully recovered its Super Heavy booster using the “chopsticks” on its launch tower. Each test provides valuable data that NASA reviews to support mission planning.

Comparing NASA's SLS and SpaceX’s HLS Contracts

NASA’s Artemis program also utilizes the Space Launch System (SLS), a heavy-lift rocket built through a traditional “cost-plus” contract model. While this model compensates contractors for base costs plus expenses, critics argue it can lead to extended development times and increased costs. In contrast, SpaceX’s HLS contract is a fixed-price agreement: NASA pays a one-time fee of $2.99 billion if milestones are achieved.

The differing contract approaches reflect NASA's evolving strategy. While the SLS program follows a traditional, highly specified model, the HLS contract allows SpaceX more flexibility, with only 27 system requirements—significantly fewer than SLS contracts require.

SpaceX’s next big hurdle is a ship-to-ship propellant transfer test, scheduled for early next year. If successful, it will be the first demonstration of large-scale in-space refueling, which could enable the transport of substantial payloads beyond Earth’s orbit. This capability would be essential for a range of missions, from uncrewed lunar cargo deliveries to more complex Mars expeditions.

Next Steps and Milestones for SpaceX’s Starship

In addition to the refueling test, SpaceX’s Starship will undergo a Critical Design Review (CDR) by Summer 2025. NASA and SpaceX are also collaborating on interior design elements, as astronauts meet monthly with SpaceX to refine details for Starship’s crew cabin, which will feature workspaces, sleeping quarters, and lab areas.

NASA has also provided guidance on certain design aspects, such as cryogenic fuel storage and thermal tiles. If SpaceX’s Starship passes all remaining tests and meets NASA’s design requirements, the mission remains on track for a lunar landing in September 2026.

As Chojnacki stated, “We have a plan in place to demonstrate these first-of-a-kind capabilities and achieve the goal of returning astronauts to the Moon.