On October 8, the Space Development Agency released a draught request for proposals for 18 spacecraft that will deliver experimental payloads. SDA’s envisioned mesh network of the 126 optically coupled data transit satellites will include these 18 spacecrafts.
The 126 satellites which are going to make up Transport Layer Tranche 1 are scheduled to launch in 2024, and SDA is already assessing proposals. The Tranche 1 Demonstration and Experimentation System (T1DES), will use the additional 18 satellites.
The adjustment happened after it was apparent that the previous plan to deploy 6 stacks of the 24 satellites was not going to work owing to launch vehicle limits, said Derek Tournear, SDA Director on the DefenseOne virtual event in September 27. The number of satellites in every stack had to be lowered to 21.
The deadline for bids for Transport Layer Tranche 1 has been extended to October 8. A mesh network will connect 126 data-relay communications satellites. SDA requested 126 “baseline” communications satellites to be deployed in 2024, as well as 18 “partner payload program” satellites (referred as P3) that is going to carry hosted payloads, in the original RFP dated August 30. The updated RFP was released on September 14th.
“T1DES will expand Tranche 1 Transport Layer constellation together with demonstration and experimental capability,” according to the preliminary request for proposals. The 18 satellites will be launched in a single plane around 600 miles above Earth, with 12 carrying industry-created payloads and six carrying government-supplied payloads. By 2025, up to 3 vendors could be chosen to build the satellites and provide launch services.
SDA will not say what kinds of payloads it is looking for. Only approved suppliers or those that have secret security clearances will be given access to the section of the RFP that defines the intended payloads.
The Transport Layer, according to the agency, will support a variety of Defense Department clients and military units. The Defense Advanced Research Projects Agency as well as the Air Force Research Laboratory are anticipated to provide government-developed experimental payloads. SDA is interested in the sensors as well as other technologies that assist the Department of Defense’s objective of using satellites in space to follow targets on the land, at sea, and in air and sharing that knowledge among military assets deployed throughout the world for industry-developed payloads.
For inter-satellite communications, T1DES satellites must utilize Ka-band frequencies and need two optical terminals. Contractors must provide fully integrated satellites and deal for launch services under “delivery in orbit” agreements.