Until February 2020, when a satellite on orbit ran out of propellant, that was the end of its life. Most major communications and military satellites are designed with prolonged lifetimes and carry enough fuel for a 15 year mission.
But the struggle for some satellite operators has been that at the end of that 15 year period, satellites running out of fuel are still working perfectly well in every other regard. Therefore, perfectly good satellites have to be decommissioned. But not anymore.
Enter Northrop Grumman’s two Mission Extension Vehicles, the first of which is already on orbit and providing life extension services to Intelsat 901 in Geostationary Orbit (GEO).
Northrop Grumman will now follow with a second MEV that will launch on an Ariane 5 mission scheduled for No Earlier Than 28 July 2020.
This second MEV will likewise go into GEO, but will rendezvous with the Intelsat 10-02 satellite to provide life extension services.
Speaking to NASASpaceflight about the two missions, Joe Anderson, Vice President of Business Development and Operations for Space Logistics, a wholly-owned subsidiary of Northrop Grumman, stated: “The MEV has been successfully performing the orbit and attitude controls of the combine stack and providing service to the 901 spacecraft.”
MEV-1 launched in October 2019 as part of a rideshare mission on a Russian Proton-M rocket. After reaching Geostationary Transfer Orbit, MEV-1 began a three-month process of firing its Solar Electric Power engine to raise itself from its transfer orbit into the GEO graveyard.
The GEO graveyard is located at an altitude of roughly 36,086 km above Earth’s surface, 300 km above GEO.
The craft then performed a series of co-located operations with Intelsat 901 before closing in for the historic first-ever docking in GEO in February 2020.
“Everything really went according to expectations,” said Mr. Anderson. “During the docking, we experienced a small attitude transient, but that was well within expectations to the customer.”
Over the following two months, MEV-1 took over numerous operations previously performed independently by Intelsat 901. The MEV brought Intelsat 901 back into position for active service by reducing its orbital inclination to just 1.5 degrees and relocating it to a new operational location of 27.5 degrees west longitude in the GEO belt.
“On April 3rd, Intelsat brought  back into service after transitioning traffic from an old satellite,” noted Mr. Anderson.
Part of that extended service involves using MEV-1 to perform fine-tune positioning of the satellite needed to carry out all of its telecommunication duties for Africa, North and South America, and Europe.
For MEV-1’s mission, Intelsat decommissioned the 901 satellite and moved it up into the GEO graveyard for rendezvous and docking operations.
However, the main result of the excellent performance of MEV-1 and a full demonstration of the docking and capture process is that MEV-2 will not be required to rendezvous with its target in the GEO graveyard. Nor will the satellite be deactivated.
Instead, MEV-2 will move directly to the main operational GEO belt and approach Intelsat 10-02 while the satellite is still actively relaying telecommunications.
“Intelsat has confirmed their desire on the next MEV, MEV-2, to do the docking directly in GEO orbit. They will be maintaining customer traffic as we do the docking with MEV-2,” noted Mr. Anderson.
This new approach, which was always the goal for future MEV operations, was aided in large part by confirmation to a high degree of accuracy that all of MEV’s systems worked as planned during Intelsat 901 operations.
That’s not to say there weren’t lessons learned that will be applied to MEV-2. Specifically, Mr. Anderson noted that one thing done on the initial rendezvous using MEV-1 that will be carried forward to MEV-2 is a practice approach to verify that all the MEV’s sensors are calibrated properly for final approach and docking to the target satellite.
“One of the key lessons learned is that we confirmed the approach we were using on MEV-1 that we want to carry forward on subsequent missions,” said Mr. Anderson. “[That involves] doing an initial rendezvous to calibrate our sensors and making sure that everything is working well before we try to attempt the actual docking.
“So one of the things [we’ll do on] the initial approach is make sure we’re seeing the spacecraft correctly before we do the actual docking.”
After that initial approach, and once the spacecraft’s systems alignment is completed and confirmed, Intelsat will establish a “maintenance window” during which MEV-2 will approach and execute the physical docking maneuver to the satellite.
Future MEV-like missions
At present, MEV-2 is the last of Space Logistics’ Mission Extension Vehicles that has been built, though if a customer wishes to purchase an additional MEV — some customers are currently in talks with Space Systems to do just that — then others may follow.
The two MEVs currently built will also have years of available operations remaining when their currently contracted jobs with Intelsat 901 and 10-02 are complete, making them available for service to other geostationary platforms until at least 2035.
At present, Space Logistics is transitioning to their next round of products, which include Mission Robotic Vehicles (a partnership with DARPA) and Mission Extension Pods.
With this fleet of offerings, it is certainly within the technological realm for an MEV-like vehicle to perform similar operations with satellites in Low Earth Orbit.
While no plan exists to use the vehicles in such a manner, an example of their potential use in Low Earth Orbit include a hypothetical rendezvous with the Hubble Space Telescope, whereafter an MEV-like craft could take over precision pointing operations for the telescope once its gyroscopes fail.
Mission Robotic Vehicles could also be used in coordination with a human spaceflight to perform servicing operations on the iconic observatory.
Additionally, a fleet of robotic vehicles could also be used, if there is a customer base for such operations, to declutter the Low Earth Orbit environment by dragging satellites into lower orbits that will decay into Earth’s atmosphere in a matter of weeks instead of years.
“All that is in the realm of possibility,” confirmed Mr. Anderson. “The technology we are developing for MEV and the Mission Extension Pods are all clearly within the capabilities of doing those sorts of missions.
“Today we don’t have a customer base for that. But everything we’re doing can be directly tied to those types of missions.”
(Lead image via Northrop Grumman)
The post Mission Extension Vehicles Validate New Satellite Lifeline in Orbit appeared first on NASASpaceFlight.com.