The latest version of the ESPA ring uses experiments, but also more advanced small operational satellites
WASHINGTON, a ring-shaped satellite that the US Air Force developed a decade ago for experimentation, has evolved into a reliable means of transporting small national security payloads into geosynchronous earth orbit.
The so-called ESPA ring — short for Evolved Expendable Launch Vehicle (EELV) Secondary Payload Adapter — was created to fill the unused capacity of national security space rockets. The latest version of the ring designed by Northrop Grumman, Long Duration Propulsive ESPA or LDPE, uses experiments but also more advanced small operational satellites.
Each ring has six ports that can hold 320 kilograms of payload per port.
“LDPE provides additional propulsion, power and avionics subsystems to enable it to function as a fully functional satellite,” Space Systems Command program manager Lieutenant Colonel Michael Rupp said in a press release.
Under contract with US Space Systems Command, Northrop Grumman built three rings of LDPE for national security missions. One took off December 2021second century November 2022 and the third will fly on the SpaceX Falcon Heavy in incoming USSF-67 mission. A more advanced version of the ring is in the works in July 2022 $22 million contract.
Space Systems Command has reported that all payloads on LDPE-1 and LDPE-2 have been successfully deployed to geostationary orbits.
The original ESPA ring originated as a joint project of the Air Force and Orbital Sciences Research Laboratory in 2012, said Troy Brashear, Northrop Grumman’s vice president of national security systems. Orbital Sciences was later acquired by Northrop Grumman.
Military customers see the usefulness of the ESPA ring as a much less expensive option than dedicated launches, and the rings are flexible enough to swap 11 o’clock payloads, Brashear said. Space news.
“The interesting part about this satellite program is the ability to make changes on the fly,” he said. This is not possible for most space missions where payloads are designed for specific interfaces and replacements are difficult to make. “With LDPE, we were able to show that cargo at each of the six ports can only be exchanged at the point of departure.”
Northrop Grumman manufactures ESPA satellites in Gilbert, Arizona. He said that after being sent to Cape Canaveral, individual payloads on recent missions were changed just before launch. “And it gave the client a lot of flexibility.”
A form of immunity
Brashear said being able to add a new payload to the mission at short notice is increasingly important form of elasticitygiving the Space Force options to deploy experiments or operational satellites in response to emerging needs.
“The foreign threat environment is changing quite rapidly. And for our customers, speed and agility are paramount to meet these challenges,” he said. “This program provides this kind of flexible architecture to get things into orbit faster and cheaper because it’s a very small satellite structure, using empty space on the ride that would be unused.”
LDPE satellites fly into geostationary orbit on large rockets that usually carry a large main payload and a ring as a secondary payload. Upon reaching orbit, the LDPE is released from the second stage. Once the ring is deployed, individual payloads can remain permanently attached to the platform, or they can be deployed as independent satellites that go off and carry out their own missions.
“The US government’s investment in ESPA products over the last 10 years has timed very well with the threat environment,” he said. “If those investments hadn’t been made 10 years ago, we wouldn’t have this freight train into space from which we could cost-effectively take six payloads.”
Another advantage of these rings is that they are interchangeable with any national security spacecraft used by the Space Force that are operated by the United Launch Alliance and SpaceX. LDPEs have been launched on Atlas 5 ULA and SpaceX Falcon Heavy. “Of course there are different loads, dynamics and tests,” said Brashear. “But the collaboration with ULA and SpaceX has been fantastic.”