Satellite servicing industry seeks interface standards
WASHINGTON — As another satellite life extension spacecraft is readied for launch, both developers and customers of such systems called for the creation of standard interfaces to support servicing of future spacecraft.
Northrop Grumman’s Mission Extension Vehicle (MEV) 2 is now scheduled to launch Aug. 15 on an Ariane 5. That launch, which was postponed by weather and technical issues with the rocket, will also place the Galaxy 30 and BSAT-4b communications satellites into orbit.
MEV-2 will rendezvous with the Intelsat 10-02 spacecraft later this year in geosynchronous orbit to extend the life of that 16-year-old satellite. Intelsat is also the customer for MEV-1, which launched last October and docked with the Intelsat 901 satellite in February.
The MEV docks with the host satellite by attaching to the nozzle of the liquid apogee motor, used to raise the orbit of the satellite after being placed into a transfer orbit by its launch vehicle but not used by the spacecraft once it reaches GEO. That nozzle, along with a launch adapter ring around it, provides a means of grappling most existing GEO satellites.
“We’re very fortunate in the fact that we have those two features available on most satellites in orbit,” said Joseph Anderson, director of Mission Extension Vehicles at SpaceLogistics, a wholly owned subsidiary of Northrop Grumman that operates the MEVs, during an Aug. 13 panel discussion of the Space Tech Expo Connect online conference. “We were able to design our Mission Extension Vehicle with a capture mechanism so that it can accommodate the different liquid apogee engines.”
That may not be the case in the future. Jean-Luc Froeliger, vice president of space systems engineering and operations at Intelsat, noted the increasing number of satellites they rely exclusively on electric propulsion, and thus lack liquid apogee motors. “They’ll need to find another interface to grab to,” he said.
Anderson said he hopes future satellites will be designed with interfaces so that servicing vehicles can dock with them. “Starting in the next few years, every satellite launched should have a grapple fixture on it, a standard grapple fixture that a servicing vehicle can use to capture,” he said.
Jonathan Goff, chief executive of Altius Space Machines, said the adoption of standard interfaces would make it easy to service satellites and even add capabilities to older satellites, drawing an analogy to USB ports on computers. “If you have an interface for it that’s standardized, that people can design to, then it becomes a lot easier to create an ecosystem of other services,” he said.
How an interface becomes a standard that gains widespread adoption is a challenge. Altius has a contract to provide grappling fixtures for OneWeb’s satellites without knowing what system may eventually be used to attach to those satellites for servicing or deorbiting them.
“It’s designed to enable as large a number of different grappling methods as possible,” Goff said, including both mechanical and magnetic systems. “We win a whole lot more if everybody’s using something similar. We can all just design to the same point.”
The issue of standard interfaces came up during an Aug. 12 webinar by Astroscale, another satellite servicing company. Jeremy Schiel, co-founder of in-space refueling company Orbit Fab, outlined several areas for standards, including docking fixtures as well as interfaces for refueling spacecraft and providing power and data connections.
“Generally agreed-upon standards are the bedrock of a healthy global economy,” he said, by reducing friction in the market. “When you have good standards in place, companies can build on that prevailing level of infrastructure.”
How those standards should be set is an open question, he said, with options such as using a global coordinating body or allowing a standard to emerge in the market, but he warned against prematurely setting one. “It’s increasingly important that we don’t put unnecessary standards on today or the next few years, letting industry have a chance to innovate and grow naturally.”
NASA is also playing a role. “There’s no excuse to do nothing. Every satellite should have something put on the back,” said Ben Reed, head of the satellite servicing projects division at NASA’s Goddard Space Flight Center, during the Astroscale webinar. He said the agency solicited designs from industry for grapple fixtures earlier this year that will be examined in a lab.
“There’s no need for the government to develop a small, lightweight grapple fixture if commercial industry has already done it,” he said. NASA will soon announce the companies it has entered into Space Act Agreements with for evaluating their grapple fixtures.
The discussions around grapple fixtures and other interface standards is a sign of the growing interest in satellite servicing and the maturity of the technologies. Another is how Intelsat is approaching its use of Northrop Grumman’s MEVs. On the MEV-1 mission, Intelsat moved the target satellite out of GEO into the “graveyard” orbit several hundred kilometers higher, in the event the docking created debris or disabled the satellite.
For the MEV-2 mission, though, Froeliger said Intelsat 10-02 will remain in GEO for the docking with servicing spacecraft. “Now that we’ve proven the concept, we’re going to dock directly at GEO,” he said. “We expect the disruption of service to be at a minimum: probably less than 30, maybe 20, minutes.”