Sierra Space proposes 18-month refueling plug standard if Space Force orders China’s SJ-25 demo

Satnews.com reported on Oct. 29, 2026, that Sierra Space executive Erik Daehler told the U.S. Space Force at the MilSat Symposium to settle the satellite refueling plug standards dispute within 18 months. The timeline applied only if the Space Force ordered a demonstration to refuel China’s SJ-25 satellite. In that case, all companies present would adapt their systems to a common interface within the period. Daehler made the proposal during a panel discussion at the conference.

Sierra Space and Northrop Grumman are each deploying fully refuelable satellites to geostationary orbit, a belt where spacecraft remain fixed above one point on Earth, but they use incompatible refueling interfaces. The physical connection used to move propellant between satellites prevents cross-refueling between the two systems. Erik Daehler, senior vice president of Sierra Space Defense, highlighted the issue during a panel at the symposium, emphasizing that the lack of standardization means servicing providers cannot refuel each other’s satellites. The interfaces are not interchangeable.

The U.S. Space Force released a common interface payload standard in 2019, but acquisition offices treat it as optional and do not require industry adoption. Owen Cupp, an executive director at Boeing, said the rule lacks mandatory enforcement despite its existence. He compared the situation to military standards that are often not strictly required.

John Rood, chair and CEO of Momentus and a former under-secretary of defense for policy, warned against mandating a single refueling plug standard. He cited outdated government standards, such as those for European hotel room plugs, as a model to avoid. Rood argued for industry-led convergence on open standards, beginning with simpler aids like grapple bars, which are handles used to grasp a satellite, and orientation markers, rather than relying on government-mandated solutions. Rood suggested that industry-led initiatives could foster innovation and flexibility in satellite servicing standards.

U.S. Space Command has prioritized sustained space maneuver and refueling capabilities, yet the U.S. Space Force has not allocated significant funding to on-orbit servicing programs. David Denhard, chief scientist and technical adviser for U.S. Space Command, acknowledged the lack of financial investment in servicing but emphasized that adversarial capabilities, including China’s refueling satellites, create urgency for U.S. funding and development.

In September 2026, the U.S. Space Force planned refueling and relocation demonstrations for 2027 with Astroscale U.S. and Starfish Space, using standardized docking fixtures. The upcoming test marks a step toward addressing interface fragmentation, though it does not yet resolve the broader industry-wide standardization issue. The demonstrations will involve refueling and relocation operations using hardware built to a common connection design.

“We’re really doing refueling because our adversaries are refueling their spacecraft so that they can fly them like fighters,” Daehler said. He framed refueling as a critical countermeasure to adversarial capabilities, saying U.S. standardization must match or exceed such advancements. Adversarial advancements drive the U.S. military’s refueling efforts, particularly China’s development of refuelable satellites like the SJ-25, which threatens U.S. operational dominance in space.

Industry groups such as CONFERS and COSMIC are encouraged to develop open standards for satellite servicing, including grapple bars and orientation markers, to avoid reliance on outdated government-mandated solutions. These industry-led groups are exploring open standards for satellite servicing to promote interoperability and flexibility.