by Douglas Messier
As space has become a war-fighting domain, the Defense Department (DOD) faces challenges in assessing how its satellites can survive threats against them, erecting a Space Fence to better track satellites and debris in Earth orbit, and upgrading the Global Positioning System (GPS), according to a new report from the director of Operational Test and Evaluation (DOT&E).
“The DOD intends to invest at least $100 billion in space systems over the next decade, and we are not alone,” the report stated. “We therefore must thoroughly understand how our systems will perform in space, particularly when facing manmade threats,” Robert F. Behler wrote in the 2019 annual report.
“Yet, the DOD currently has no real means to assess adequately the operational effectiveness, suitability, and survivability of space-based systems in a representative environment,” he added. (Download full report)
Behler said DOT&E is working with the Test Resource Management Center (TRMC) to develop “a space warfighting combined test force, a ‘National Space Test and Training Range,’ and ground-based space test facilities. The threat array would include cyber, directed-energy, kinetic and electronic warfare threats, as well as natural hazards.”
The test force “would enable validation of space-based warfighting [tactics, techniques, and procedures], and development of multi-domain operating concepts,” the report added. “It also would provide more effective warfighter training, directly supporting the Secretary of Defense’s call for greater force readiness.”
Space Fence Testing
A key element for keeping U.S. space assets safe is being able to track satellites and debris in Earth orbit. The U.S. Air Force has been erecting a Space Fence (SF) to enhance its ability to detect and track these objects.
The fence is a S-band radar system that detects, tracks and characterizes objects in Earth orbit using a site on Kwajalein Atoll in the Marshall Islands and an operations center in Huntsville, Ala.
The Space Fence is primarily focused on detecting and tracking objects in low Earth orbit (LEO), with additional capability for medium Earth (MEO) and geostationary Earth (GEO) orbits.
Behler’s organization conducted testing on the Space Fence from Aug. 6 through Nov. 1.
“SF demonstrated the capability to find many small objects that had not previously been tracked or cataloged,” the report stated. “Once SF becomes operational, the number of tracked following preliminary findings: objects confirmed orbiting the earth is expected to grow significantly.”
Although the fence met its accuracy requirements for LEO, it was not as effective in tracking objects in higher orbits. SF was also limited in its ability due to its single site.
“However, with only one sensor site, SF does not have the power or coverage to be able to continuously track and maintain awareness of these small objects,” the report said.
Plans call for the construction of a second radar site in Australia. Funding for the facility has not been approved yet, the report added.
The testing found a number of technical issues as the Space Fence was being stood up. Software issues prevented the system from consistently planning, scheduling and conducting tasks correctly.
The glitches resulted in operators spending more time monitoring automated tasks and correcting missed observations, the document said. Software patches have largely addressed the problem.
“Network latency is affecting system performance between the SF Operation Center and the Sensor Site causing queries and tasks to time out, often forcing a reset of the system client interface,” the report stated.
The review also found inadequate user training prior to the start of operational testing. System and user documentation also lacked final corrections, processes and procedures before testing began.
Global Positioning System (GPS)
The Air Force is upgrading the satellite navigation system with advanced GPS III spacecraft, improved ground control systems, and upgraded military user equipment that will provide greater accuracy, anti-jamming capabilities, cyber security and military signals.
There are currently 31 operational GPS satellites in Earth orbit. The upgraded constellation will include 10 GPS III satellites and 22 GPS III Follow-on Production (GPS IIIF) satellites.
Two advanced GPS III spacecraft have been launched. Officials expect contractor Lockheed Martin to have the first GPS IIIF satellite available for launch in 2026.
“GPS III lacks a testing plan with adequate space threat representation. The Program Office plans to conduct environmental testing, but it is not currently planning for sufficient test articles to support full characterization of adversary threats against the system,” the report stated.
“More work is needed to comprehensively replicate space threats, their effect on the space segment, mitigation efforts, and the strategy to conduct operational space segment testing using realistic threats,” the document added.
The Air Force is also upgrading the control segment, which includes ground stations, satellite antennas, and geographically distributed monitoring and tracking stations.
DOT&E’s review identified concerns in the development of upgraded military GPS user equipment (MGUE).
“The MGUE program continues to experience delays integrating the new technology into the lead platforms and in developing final software and hardware builds by MGUE vendors,” the report stated.
The report recommended that the U.S. Air Force:
- conduct operational testing of the GPS Enterprise against
current and emerging space threats, to assess the ability of
the system and its operators to support DOD missions in a
contested space environment.
- inform users of GPS across the DOD of GPS Enterprise
test results and schedule delays, to enable users to plan for
integration of new GPS capabilities.