WASHINGTON \u2014 Procurements of certain elements of the U.S. military\u2019s low Earth orbit satellite constellation known as the Proliferated Warfighter Space Architecture (PWSA) are on hold as the Pentagon reviews acquisition options and shifts responsibility for parts of the program outside the Space Development Agency (SDA).<\/p>\n
SDA, a U.S. Space Force organization created in 2019, was tasked with fielding a large constellation of low Earth orbit satellites using rapid, iterative procurement cycles. The architecture is intended to support missile warning, tracking, communications and other military missions through multiple \u201clayers\u201d<\/a> of satellites launched in two-year tranches.<\/p>\n GP Sandhoo, acting director of SDA, said a planned procurement of satellites for the next increment of the PWSA\u2019s data transport layer remains paused, along with the acquisition of a separate \u201ccustody layer\u201d designed to maintain continuous tracking of mobile targets on Earth\u2019s surface.<\/p>\n \u201cCustody is still getting shaken out,\u201d Sandhoo said last week at the SmallSat Symposium in Mountain View, California. \u201cIt\u2019s just been interesting times,\u201d he said, referring to potential realignments in the procurement of the PWSA.<\/p>\n The pause marks a shift from SDA\u2019s previous cadence, under which contracts for new tranches of satellites were awarded roughly every other year across different layers of the architecture.<\/p>\n Sandhoo said procurement of the tracking layer \u2014 satellites equipped with infrared sensors to detect missile launches and follow them through flight \u2014 is moving forward<\/a>. The custody layer, which would provide persistent tracking of maneuvering targets and maintain a continuous track file over time, is going to be acquired under a different organization.<\/p>\n \u201cThe solution may not come for SDA,\u201d Sandhoo said, noting that the custody layer likely will be the responsibility of a new Space Force portfolio acquisition executive focused on space-based sensing and targeting<\/a>. \u201cSo there\u2019s a lot of swirl,\u201d Sandhoo said, \u201cbut the fact remains that these capabilities are needed by the joint force, and somebody\u2019s gonna be doing this stuff.\u201d<\/p>\n He said the sensing and targeting office is expected to release a request for industry information for Air Moving Target Indicator, or AMTI, satellites. AMTI sensors are designed to detect, track and characterize airborne moving objects across wide areas, enabling continuous custody of a target throughout its flight.<\/p>\n Transport layer under review<\/p>\n Plans for Tranche 3 of the transport layer also are uncertain. \u201cOn the transport side of things, that is still up in the air,\u201d Sandhoo said.<\/p>\n The transport layer functions as the data backbone of the PWSA. It is designed as a mesh network of satellites equipped with Link 16 tactical data terminals and optical intersatellite links, which use laser communications to move large volumes of data between spacecraft. The layer is intended to relay missile warning and tracking data across the constellation, route it to ground stations for processing, or transmit it directly to users such as ships and aircraft.<\/p>\n Under SDA\u2019s original plan, Tranches 1 and 2 would provide limited regional capability, while Tranche 3 would expand coverage globally.<\/p>\n Part of the reassessment is driven by the administration\u2019s increased focus on homeland defense, Sandhoo said. \u201cBut again, the ability to be able to detect and track these threats, to move the information out to users to do something about it is not going to go away,\u201d he said. \u201cSo that will get shaken out at some point, hopefully sometime soon.\u201d<\/p>\n The transport layer is being absorbed into a broader Space Force-led space data transport initiative. The Space Warfighting Analysis Center (SWAC) is leading architecture studies to determine how future military satellite communications and data relay capabilities should be structured and integrated across classified and unclassified systems.<\/p>\n One option under review would replace future tranches of SDA\u2019s transport satellites with SpaceX\u2019s Starshield spacecraft<\/a>, a military variant of the company\u2019s commercial Starlink broadband constellation. The potential shift has drawn scrutiny from lawmakers<\/a>, who have argued that replacing SDA\u2019s multi-vendor tranche model with a single-provider solution could weaken competition and reduce industrial base diversity.<\/p>\n \u201cSo there\u2019s a force design that has to happen at some point,\u201d Sandhoo said. \u201cSpace Force has been focused on providing backward compatibility to everything out there. At some point in the future, they have to have a force design that defines the architecture,\u201d he added. \u201cWe are working closely with the SWAC.\u201d<\/p>\n It remains unclear how the changes will affect SDA\u2019s role in setting contracting strategies and pacing tranche procurements, as the Space Force reasserts more centralized control over portions of the architecture.<\/p>\n Supply chain issues persist<\/p>\n For tranches already under contract \u2014 Tranche 0, Tranche 1 and Tranche 2 \u2014 Sandhoo said supply chain constraints<\/a> continue to affect the program<\/a>. The most significant bottlenecks involve optical communications terminals, which enable laser crosslinks between satellites, and encryption devices used to secure data.<\/p>\n He also cited industry challenges with satellite checkout, the post-launch process of verifying that spacecraft subsystems and payloads are functioning properly before entering operational service.<\/p>\n \u201cOn the checkout side, there\u2019s many,\u201d Sandhoo said of bottlenecks. \u201cI don\u2019t think a lot of the industry is geared to do checkout.\u201d He noted that traditional military satellite programs typically require checkout for only one or two spacecraft. \u201cTrying to do this on 40 to 50 satellites is a little different,\u201d he said. \u201cSo I think there\u2019s some challenges there on the industry side, both from throughput perspective, testing perspective, and also on orbit checkout perspective.\u201d<\/p>\n