With less than a week to go before earnings day, satellite communications start-up stock AST SpaceMobile (ASTS 13.91%) announced on Wednesday that it has won a $43 million subcontract on a Space Force award.

AST SpaceMobile stock is up 16.7% through 10 a.m. ET.

Details, please

AST seems to be playing this news close to the vest. Management revealed the size of the award and that its role will be to "support ... the United States Space Development Agency (SDA) [which is part of the U.S. Space Force] through a prime contractor."

AST stated that it "will accelerate delivery of needed space-based capabilities to the joint warfighter." It also hinted at specifics, noting that the contract win "follows successful testing on BlueWalker-3 in orbit under the previous contract announced in February 2024." So the contract appears to have something to do with direct-to-cell communications service.

And AST noted that the contract falls under the Space Force's Proliferated Warfighter Space Architecture (PWSA) program. But that's about as specific as AST was prepared to get, not even confirming the identity of the prime contractor that has subcontracted work to AST.

Who is AST SpaceMobile working for?

AST's immediate customer on this contract remains a mystery, but we can at least narrow the range of suspects. So far, Space Force's SDA has awarded prime contracts to the following companies:

• L3Harris (LHX -0.41%)
• Lockheed Martin (LMT -0.73%)
• Northrop Grumman (NOC -0.72%)
• Rocket Lab (RKLB 4.54%)
• RTX (RTX 0.42%)
• SpaceX
• York Space Systems

But SDA has also named a whole host of other companies as permitted to bid for work on an offshoot of PWSA, dubbed the Hybrid Acquisition for Proliferated Low Earth Orbit (HALO) program. There's some overlap between the companies involved in PWSA and those involved in HALO, so it's likely that AST's new $43 million contract is with one of the companies named above.

When AST SpaceMobile reports Q4 earnings after close of trading on Monday, March 3, we may learn the answer.