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<\/p>\nUnited Launch Alliance carried out an Atlas V launch Friday with the third pair of GSSAP satellites for the US Space Force. Flying in its never-before-used 511 configuration, Atlas lifted off from Cape Canaveral Space Force Station at 2:00 PM EST (19:00 UTC) for a lengthy mission that injected the satellites into a near-geostationary orbit.<\/p>\n<\/p>\n
The GSSAP (Geosynchronous Space Situational Awareness Program) is a US Space Force project using small satellites to inspect other spacecraft operating in geostationary orbit. Friday\u2019s launch, which is designated USSF-8 (US Space Force 8), is carrying the fifth and sixth satellites in this series.<\/p>\n
With the deployment of these two satellites, the Space Force is continuing a program which has given them a new capability in recent years to study foreign satellites and monitor their operations in orbit. This likely builds on the earlier experimental MiTEx (Microsatellite Technology Experiment) satellites which performed an array of experiments including satellite inspections during their time in geostationary orbit in the 2000s.<\/p>\n
Alongside GSSAP, a series of demonstration missions are being undertaken to further improve the capabilities of so-called \u201cspace situational awareness\u201d satellites, including the ANGELS (Automated Navigation and Guidance Experiment for Local Space) satellite that shared a ride to orbit with the first two GSSAP spacecraft, and the Mycroft satellite launched in 2018.<\/p>\n
GSSAP satellites are manufactured by Northrop Grumman, formerly Orbital ATK, and are based on the lightweight GeoStar-1 bus. This is a three-axis stabilized platform incorporating the systems that enable the satellite to carry out its mission. Each satellite is powered by a pair of deployable solar arrays and are capable of maneuvering on-orbit to set up inspection passes of other spacecraft.<\/p>\n
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A pair of GSSAP satellites in orbit (Credit: US Space Force)<\/p>\n
The first GSSAP launch took place in July 2014, designated AFSPC-4 (Air Force Space Command 4). At this point, GSSAP was a US Air Force program, with the formation of Space Force over five years in the future. The twin satellites were carried aloft by a Delta IV M+(4,2) rocket which deployed them and their ANGELS co-passenger, close to geostationary orbit. Another pair of spacecraft were launched by another Delta IV rocket in August 2016 as AFSPC-6. Prior to the program\u2019s transfer to Space Force, the USSF-8 mission was to have been designated AFSPC-8.<\/p>\n
The USSF-8 launch comes shortly after the retirement of the first two GSSAP satellites, with GSSAP-1 being decommissioned and moved to a \u201cgraveyard\u201d orbit above the geostationary belt around the start of last February. GSSAP-2 joined it in retirement in early October. The arrival of GSSAP-5 and 6 will restore the constellation to four satellites, although it is not clear for how much longer GSSAP-3 and 4 will be able to remain in service as they are only one year younger than GSSAP-1 was when it was withdrawn.<\/p>\n
Astronomy (adsbygoogle = window.adsbygoogle || []).push({});<\/p>\n In addition to their own names and their launch designations, the GSSAP satellites in orbit have also been assigned numbers under the series of USA designations given to most US military spacecraft. The first pair were designated USA-253 and 254, while the second pair are USA-270 and 271. USA designations are assigned sequentially, and the most recently-announced example was USA-319, given to the GPS-III-05 satellite launched last June. Assuming no unannounced numbers have been assigned in the meantime, this means that GSSAP-5 and 6 will most likely be given the designations USA-320 and USA-321 once they reach orbit.<\/p>\n Atlas V Rocket<\/p>\n Friday\u2019s launch was carried out by the ULA (United Launch Alliance). Formed in 2006 through the consolidation of the rocket programs of Boeing and Lockheed Martin, ULA has been the premier launch services contractor to the US government since its inception\u2014although this position has more recently come under threat with the advent of SpaceX and other new aerospace companies coming through. ULA inherited Boeing\u2019s Delta II and Delta IV rockets as well as Lockheed Martin\u2019s Atlas V, with the older Delta II being phased out in 2018 and the single-core versions of Delta IV following in 2019.<\/p>\n<\/p>\n