WASHINGTON — SpaceX and and L3 Harris will contribute satellites to track hypersonic weapons to the Space Development Agency’s planned mega-constellation, with the nascent agency announcing Oct. 5 it has selected the two companies to build its first wide field of view satellites.

Under the contracts, each company will design and develop four satellites equipped with wide field of view (WFOV) overhead persistent infrared (OPIR) sensors. Operating in low Earth orbit, the sensors will make up the inaugural tranche of the SDA’s tracking layer — the Pentagon’s new effort to track hypersonic weapons from space.

“This SDA tracking layer is going to consist of a proliferated, heterogeneous constellation of WFOV space vehicles that provide persistent global coverage and custody capability. That’s going to combine with activities in the Missile Defense Agency as they build toward their Hypersonic and Ballistic Tracking Space Sensor (HBTSS) medium field of view (MFOV) space vehicles,” Acting Deputy Undersecretary for Research and Engineering Mark Lewis told C4ISRNET.

Per the announcement, SpaceX will receive $149 million, while L3 Harris will receive $193 million. According to SDA Director Derek Tournear, the awards were the result of a full and open competition, with the selection based purely on technical merit.

SpaceX has made waves with its Starlink constellation — a series of satellites built to provide commercial broadband from low Earth orbit — and the Department of Defense has tested using Starlink to connect various weapon systems. However, the company does not have a history building OPIR sensors.

According to Tournear, the company will work with partners to develop the sensor, which it will then place on a bus it is providing. SpaceX already has a production line in place to build a bus based on its Starlink technologies, added Tournear.

“SpaceX had a very credible story along that line — a very compelling proposal. It was outstanding,” he said. “They are one of the ones that have been at the forefront of this commercialization and commodification route.”

L3 Harris will develop an OPIR solution based on decades of experience with small satellites, small telescopes and OPIR technologies.

“They had an extremely capable solution. They have a lot of experience flying affordable, rapid, small satellite buses for the department,” noted Tournear. “They had the plant and the line in place in order to produce these to hit our schedule.”

Tracking hypersonic weapons

The contracts are the latest development as the SDA fleshes out its National Defense Space Architecture (NDSA), a new constellation to be comprised of hundreds of satellites primarily operating in low Earth orbit. These satellites are expected to make up tranche 0 of the SDA’s tracking layer, which will provide global coverage for tracking hypersonic threats.

The glue that holds the NDSA together will be the transport layer, a space-based mesh network made up of satellites connected by optical intersatellite links. Like most planned SDA satellites, WFOV satellites will plug directly into that network.

“The idea is it connects to the National Defense Space Architecture — the NDSA transport layer — via optical intersatellite links,” said Lewis. “And that will enable low latency dissemination for missile warning indications. It will provide track directly to the joint war fighters.”

SDA issued two contracts in August for its first 20 transport layer satellites. York Space Systems was awarded $94 million to build its 10 satellites, while Lockheed Martin was awarded $188 million for its 10 systems.

That transport layer capability is essential to the tracking layer’s mission.

Because they are so much closer to the Earth’s surface than the U.S. Space Force’s missile tracking satellites in geosynchronous orbit, the WFOV sensors will naturally have a much more limited field of vision. In order to track globe traversing hypersonic missiles, the WFOV satellites will have to work together.

Once the first satellite picks up a threat, it will begin tracking it until it disappears over the horizon. During that time, it is expected to transmit its tracking data to other WFOV satellites over the transport layer. So as the first satellite loses sight of the threat over the horizon, the next WFOV is ready to pick it up, and so on and so forth.

From there, the WFOV satellites will pass the tracking data — either directly or via the transport layer — on to the medium field of view satellites being developed by the Missile Defense Agency as their HBTSS.

“SDA is developing the low cost proliferated WFOV space vehicles that provide the missile warning and the tracking information for national defense authorities, as well as tracking and cueing data for missile defense elements,” explained Lewis. “Meanwhile, the Missile Defense Agency is developing the high resolution HBTSS MFOV space vehicles — those can receive cues from other sources including the WFOV system — and they’ll provide low latency fire control quality tracking data.”

“The MFOV HBTSS satellites will then be able to hone in and actually be able to calculate the fire control solution for that missile, send those data to the transport satellites with a laser [communication] system … and then the transport system will disseminate that to the weapons platform as well as back to" the continental United States, where MDA can broadcast that information, added Tournear.

MDA issued $20 million contracts to Northrop Grumman, Leidos, Harris Corporation and Raytheon to develop HBTSS prototypes in Oct. 2019. Tournear noted that proposals for HBTSS “are being written as we speak.”

Together, HBTSS and the SDA’s tracking layer are meant to provide the data needed to take out hypersonic threats — which Congress is increasingly concerned by.

“It’s part of an integrated DoD OPIR strategy. So the wide field of view sensors and the medium field of view sensors are really integral to this whole NDSA system and legacy strategic missile warning capability,” said Lewis, praising MDA and SDA for working together to build a heterogeneous solution.

Spiral development

Of course, this initial tranche won’t provide global coverage up front. As part of its spiral development approach, SDA plans to continuously add satellites to its mega-constellation in two-year tranches, with each tranche including more advanced technology. The tracking layer is not expected to reach global coverage until 2026, said Tournear.

But as the constellation is built out, the more limited initial capabilities will be used to help integrate the space-based assets with war fighters.

“We call tranche 0 our war fighter immersion tranche,” said Tournear. “What that means is, its goal is to provide the data in a format that the war fighters are used to seeing on tactical timelines that they can be expected to see once we actually become operational. The whole purpose of tranche 0 is to allow the war fighters to start to train and develop tactics, techniques and procedures so that they can create operational plans for a battle where they would actually incorporate these data.”

With tranche 1 in 2024, the tracking and transport layers will essentially reach initial operating capability, said Tournear. That will include persistent regional coverage.

According to Tournear, the tranche 0 satellites are set to launch in September 2022.

Tournear told C4ISRNET his agency is planning to issue a separate solicitation for launch services later this week. That solicitation will cover all of the tranche 0 satellites, including the 20 transport layer satellites the agency ordered in August, the eight WFOV satellites and the HBTSS satellites.

Nathan Strout covers space, unmanned and intelligence systems for C4ISRNET.

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