FALLS CHURCH, Va. — The 72 data-transport satellites that the Space Development Agency plans to launch to orbit in 2026 can be probably the most complex yet, and can carry communications payloads which have never been deployed in low Earth orbit, a senior agency official said Aug. 29.
These satellites, which make up the Tranche 2 Transport Layer Beta portion of a U.S. military mesh network, have “recent capabilities that now we have not done before, including direct-to-weapon” communications, said Frank Turner, SDA’s technical director.
Turner spoke on the ExecutiveBiz space technology conference.
SDA split the $1.5 billion Tranche 2 Beta satellite order between Lockheed Martin and Northrop Grumman, firms that had previously won contracts for Tranche 1 Transport Layer satellites.
A corporation under the U.S. Space Force, SDA is constructing a mesh network of military satellites in low Earth orbit — called the Proliferated Warfighter Space Architecture — that features an information transport layer and a missile-tracking sensor layer.
Six bids were received for the Tranche 2 Beta contracts. Turner said the agency would have preferred to pick more vendors but had limited options because only experienced DoD contractors understand the best way to work with highly complex radios and waveforms required for military tactical communications.
Turner said SDA desires to work with a broader base of prime contractors and doesn’t favor “incumbents,” but few firms within the industry can handle the unique mission payloads of Tranche 2 Beta.
These satellites must be integrated with radios using the UHF (Ultra High Frequency) and S-band frequencies required by military and intelligence units in the sphere. Each satellite also has an Integrated Broadcast Service (IBS) payload. IBS is a legacy DoD network for transmitting tactical and strategic intelligence and targeting data from multiple sources. In space, IBS payloads operate from satellites in geosynchronous orbit just like the Mobile User Objective System (MUOS), developed by Lockheed Martin.
With the Transport Layer, SDA will seek to supply the identical service from low Earth orbit, which has never been done before, said Turner. “That’s not a trivial problem. It’s a really difficult problem.”
These payloads are “capabilities the warfighter asked for,” he said. “They need direct-to-weapon connectivity to enable engagements.”
The Beta satellites will attempt “extremely difficult” contacts with aircraft and missiles in flight, Turner added.
Industrial-like approach
As SDA builds DoD’s mesh network, the four-year-old agency is pursuing a commercial-like approach, counting on a broad base of suppliers of small satellites and laser communications terminals.
Turner said the choice to pick two incumbent providers for Tranche 2 Beta was not “made calmly, and was agonized over.”
“There was plenty of discussion,” he said. “Because we actually need to give you the chance to expand our supplier base.”
Turner said SDA officials are currently in conversations with military leaders about what capabilities could be needed in Tranche 3 of the Transport Layer.
Meanwhile, the agency is preparing to launch its second batch of Tranche 0 satellites this week. In September 2024 it plans to begin launching 126 Tranche 1 satellites.
The Tranche 1 satellites, equipped with inter-satellite optical links, “are the infrastructure,” said Turner. “Tranche 1 is putting a basic capability in space.”
With Tranche 2 is when “we are going to give you the chance to support communications.”