WASHINGTON — The Space Development Agency remains optimistic it will launch next month the first satellites of a planned mesh network of sensors and communications nodes in low Earth orbit, the agency’s director Derek Tournear said Nov. 10.

“We have high confidence … but there’s obviously risk there because we are pushing industry to go as quickly as possible,” he said on an online forum hosted by the National Security Space Association.

SDA’s goal is to deploy 28 satellites in two launches contracted with SpaceX, one in December and one in March. These include 20 satellites that make up the Transport Layer Tranche 0, and eight for the Tracking Layer Tranche 0. 

The December mission is expected to carry four tracking satellites made by SpaceX and an unspecified number of Transport satellites made by Lockheed Martin and York Space Systems. This launch was originally scheduled in late September but was delayed due to supply chain problems that have affected all vendors in the program.

The March mission will include four L3Harris Tracking Layer Tranche 0 satellites and an unspecified number of Transport Layer satellites. 

Tournear said it’s important for the agency to get Tranche 0 satellites on orbit by March so they can be tested in military exercises next summer. 

“Tranche 0 is our minimum viable product to do a demonstration that shows that we can get data from a satellite to a targeting cell … and that we can detect and track a hypersonic glide vehicle,” Tournear said. “Those are our two demonstrations that we want the warfighter to experiment with.”

The satellites trying to make the December launch are “in integration right now, doing last minute finishing touches, putting the payloads on the satellites,” he said. “There was some ground software that we actually had to change.”

SDA reassigned the ground software development that was being done by the Naval Research Laboratory to the satellite contractors “to help with the schedule,” Tournear said. “There’s not a lot of margin.”

Tournear said there’s also some risk in the schedule of L3Harris’ satellites. “It’s something that we’re tracking daily to make sure that we get the parts delivered and the satellites built on time.”

The first Tranche 0 launch is SDA’s main focus right now, he said. “We are all tracking this every day, almost hourly.”

People are used to seeing Starlink launches go up every month with a lot of satellites, Tournear noted. SpaceX makes it look easy “but it does take years to get this kind of model up and running and going.”

Tournear said his biggest worries regarding SDA’s constellation are cyber attacks and supply chain issues.

“Those are the ones that keep me up at night,” he said. 

There are two main concerns about the supply chain. One is the possibility that an adversary infiltrates the supply chain and inserts counterfeit components. 

The other is having enough resiliency in the supply chain so the government is not dependent on a single supplier, a problem that contributed to the delays in the Tranche 0 satellites. Tournear said the vendors producing Tranche 1 satellites for the next deployment are seeing improvements in their supply chains.

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...