FALLS CHURCH, Va. — The 72 data-transport satellites that the Space Development Agency plans to launch to orbit in 2026 will be the most complex yet, and will carry communications payloads that 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 “new capabilities that we have not done before, including direct-to-weapon” communications, said Frank Turner, SDA’s technical director. 

Turner spoke at the ExecutiveBiz space technology conference. 

SDA split the $1.5 billion Tranche 2 Beta satellite order between Lockheed Martin and Northrop Grumman, companies that had previously won contracts for Tranche 1 Transport Layer satellites. 

An organization under the U.S. Space Force, SDA is building a mesh network of military satellites in low Earth orbit — called the Proliferated Warfighter Space Architecture — that includes a data 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 select more vendors but had limited options because only experienced DoD contractors understand how to work with highly complex radios and waveforms required for military tactical communications.

Turner said SDA wants to work with a broader base of prime contractors and does not favor “incumbents,” but few companies in the industry can handle the unique mission payloads of Tranche 2 Beta. 

These satellites have to be integrated with radios using the UHF (Ultra High Frequency) and S-band frequencies required by military and intelligence units in the field. 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 like the Mobile User Objective System (MUOS), developed by Lockheed Martin.

With the Transport Layer, SDA will seek to provide the same service from low Earth orbit, which has never been done before, said Turner. “That’s not a trivial problem. It’s a very difficult problem.”

These payloads are “capabilities the warfighter asked for,” he said. “They want direct-to-weapon connectivity to enable engagements.”

The Beta satellites will attempt “extremely difficult” contacts with aircraft and missiles in flight, Turner added. 

Commercial-like approach

As SDA builds DoD’s mesh network, the four-year-old agency is pursuing a commercial-like approach, relying on a broad base of suppliers of small satellites and laser communications terminals.

Turner said the decision to select two incumbent providers for Tranche 2 Beta was not “made lightly, and was agonized over.”

“There was a lot of discussion,” he said. “Because we really want to be able to expand our supplier base.”

Turner said SDA officials are currently in conversations with military leaders about what capabilities would 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 start 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 will be able to support communications.”

Sandra Erwin writes about military space programs, policy, technology and the industry that supports this sector. She has covered the military, the Pentagon, Congress and the defense industry for nearly two decades as editor of NDIA’s National Defense...