Rocket Lab still hasn’t commented on their massive new contract win, and we’ll likely have to wait until after Christmas to hear more, but SpaceNews cites sources that unsurprisingly point to SDA:

SDA Director Derek Tournear speaking at a conference earlier this month said the agency was negotiating a contract with an unspecified supplier for 18 satellites to expand the U.S. military low Earth orbit constellation.

…Tournear said Dec. 7 at a National Security Space Association event that SDA was planning to add another 18 Beta satellites to the constellation and was in negotiations with another vendor that he did not disclose.

The Transport Layer Tranche 2 Beta satellites — projected to launch in 2026 and 2027 — will carry radios using the UHF (Ultra High Frequency) and S-band frequencies that military and intelligence units rely upon for voice and low-speed data transmissions.

“We are looking at putting another approximately 18 satellites on contract, and we’re working with a third vendor to do that, and we should make that announcement shortly,” Tournear said Dec. 7 at the NSSA forum.

While unconfirmed, SDA was my first thought when I read the SEC disclosure. I think the likelihood that this is confirmed in a few days is extremely high.