As the Space Development Agency (SDA) prepares to release a solicitation for Tranche 1 of the National Defense Space Architecture (NDSA) on Aug. 30, the agency is also working to establish command and control of two General Atomics Laser Interconnect Networking Communications System (LINCS) microsatellites that are to demonstrate optical space-to-space and space-to-air communications links–the latter next year with a General Atomics MQ-9 Reaper drone.

The two LINCS microsatellites are “the only ones [of the SDA satellites launched so far] that have some anomalies,” SDA Director Derek Tournear told reporters in a briefing at the Space Foundation’s Space Symposium on Aug. 24.

“They were launched differently, on the ‘surfboard’ on the launch vehicle, which is a way you can integrate and launch extremely quickly on these Transporter rides,” Tournear said. “We know that satellites are tumbling, and since we have limited ground station connectivity, we haven’t been able to get positive command and control of them. The satellites are on. They’re operational. We have a heartbeat from them, but we’re working with commercial ground providers in the high and low latitudes so we can get multiple contacts per day so we can get connecitvity with those, We’re still very optimistic that we’ll be able to get command and control and start to do that mission.”

In response to a question at the Aug. 24 briefing, Tournear suggested that SDA may try to test optical space-to-air links with other aircraft.”The Reaper is the only one I’ll comment on at this time as part of the LINCS demo,” Tournear said. “Other ones that we have, we have mission partners that prefer for us not to disclose what actual aircraft they’re going down, but I will say that if any mission partners–industry or government–has an aircraft that they are willing to modify and want to put an optical cross link, we’re always looking for additional partners to team with to do optical air-to-space demos.”

The LINCS are among six SDA satellites on orbit. The agency launched its first two satellite missions on June 30–the LINCS microsatellites, two Astro Orbital-built Mandrake II cube satellites with an SA Photonics payload, and a Loft Orbital satellite carrying the Prototype On-orbit Experimental Testbed (POET) payload (Defense Daily, June 30). The latter is to demonstrate a low-latency “battle management capability” in space.

SpaceX Falcon 9 rocket launched the rideshare satellites on the Transporter 2 mission. SDA’s first two sets of experimental satellites are “to gather data on optical communication terminal (OCT) performance in low-Earth orbit (LEO),” while the POET payload is to demonstrate “on-orbit data fusion, proving out core capabilities required for SDA’s future development efforts” for NDSA’s edge processing, SDA has said.

“Optical links between space, air, and ground assets offer significantly higher data rates and lower latency when compared to conventional radio frequency links, and demonstrate a pathway of getting real-time data to warfighter,” per the agency.

The sixth SDA satellite on orbit is a payload effort by SDA, the Missile Defense Agency, and Northrop Grumman [NOC] for the latter’s Cygnus resupply spacecraft for the International Space Station–a mission that will collect data “to understand how data transmits through earth’s atmosphere,” Tournear said.

The NDSA will effectively be an optically-connected Internet in space to provide tactical data–low latency communications and targeting information–to military forces in the field.

The backbone of NDSA, the Transport Layer, is to provide the targeting of ground and maritime targets, while the Tracking Layer–the Next-Generation Overhead Persistent Reconnaissance (Next-Gen OPIR) constellation–is to establish effective targeting of advanced missiles.

The Transport Layer mesh network satellites are to provide the rapid targeting of ground and maritime targets to military forces over Link 16. The optically-connected satellites will also supply position, navigation and timing to U.S. and allied forces in GPS-denied environments.

In addition, SDA is working to aid future intelligence, surveillance, and reconnaissance (ISR) satellites in the Custody Layer to fuse ISR tracking with the Transport Layer to devise the best targeting solution.

Tranche 0–the so-called “warfighter immersion” tranche–will consist of 28 demonstration satellites, 20 in the Transport Layer and eight in the Tracking Layer, for military forces to use in exercises and to develop tactics.

Those satellites are to launch in September next year.

Tranche 1, by contrast, will be an operational constellation. The solicitation to be released Aug. 30 for Tranche 1 is to be for 144 Transport Layer satellites built by three suppliers. The Transport Layer satellites are to launch in September 2024, while the Tracking Layer satellites are to launch a year later.

Last August, SDA awarded $281.5 million in firm, fixed-price contracts to Lockheed Martin [LMT] and York Space Systems to build 10 satellites each for Tranche O of the Transport Layer (Defense Daily, Sep. 1, 2020).

In addition to the 20 Transport Layer satellites for Tranche 0, the latter also will include eight satellites in the Tracking Layer–four by L3Harris Technologies [LHX] and four by SpaceX. Those eight satellites will be an initial SDA stab at monitoring threats from hypersonic and other advanced missiles.

SDA believes that the projected hundreds of low-cost Transport Layer satellites–each less than $14 million–will help deter DA-ASAT attacks, while the 1,000-kilometer polar orbit of the satellites will help protect them against ground-based directed energy attacks.