Why Intelsat’s going with life extension over refueling

Intelsat-901, a 17-year-old communications satellite running low on propellant, is awaiting a first-of-its-kind service call from a robotic spacecraft carrying a fresh tank of fuel.
SpaceNews.com

            This article originally appeared in the June 4, 2018 issue of SpaceNews magazine.
Intelsat-901, a 17-year-old communications satellite running low on propellant, is awaiting a first-of-its-kind service call from a robotic spacecraft carrying a fresh tank of fuel.
Orbital ATK’s first Mission Extension Vehicle, MEV-1, is slated to launch in early next year on a groundbreaking mission to dock with Intelsat-901 and take over orbital station-keeping duties, extending the satellite’s service life by several more years.
But first the two spacecraft will spend two or three months in a graveyard orbit 300 kilometers above Intelsat-901’s geostationary neighbors conducting tests and demonstrating the pair can fly as a connected unit before climbing back down under MEV-1’s control and return to commercial service sometime in 2019.
It’s been just over two years since Intelsat — one of the world’s largest satellite fleet operators — signed on as the first customer for the satellite-servicing venture Orbital ATK revived under its SpaceLogistics subsidiary after its ViviSat joint venture with U.S. Space ended in a lawsuit.
In December, the U.S. Federal Communications Commission gave SpaceLogistics approval to rendezvous and dock with Intelsat-901, a Space Systems Loral-built satellite that’s being replaced by the high-throughput Intelsat-37e satellite Intelsat launched in September to serve the Americas, Africa and Europe.
Earlier this year, Intelsat ordered a second Mission Extension Vehicle from Orbital ATK. Intelsat hasn’t said which one of its more than 50 geostationary satellites will be given an extended lease on life when MEV-2 enters service in mid-2020.
Ken Lee, Intelsat’s senior vice president of space systems. Credit: Intelsat
Intelsat is not a stranger to satellite servicing. In 1992, the crew of NASA’s Space Shuttle Endeavour grappled the Intelsat 603 satellite stranded in low Earth orbit and attached a new kick motor, saving the mission. In 2011, Intelsat signed a contract with MDA Corp., now part of Maxar Technologies, for a satellite servicing mission that never materialized.
Though Space Systems Loral and fellow Maxar acquisition MDA are offering a satellite-servicing spacecraft that can refuel and repair an ailing satellite, Intelsat is more comfortable with MEV’s simpler approach — at least for now.
“We are also looking at additional capabilities. It’s not just limited to MEV,” Ken Lee, Intelsat’s senior vice president of space systems, said during an interview from his Tysons Corner, Virginia, office late last month. “We might be looking at refueling and other concepts for life extension.”
Are you designing satellites today with satellite servicing in mind?
Good question. Satellite servicing could mean many things. The MEV approach that we have taken is the more conservative technology choice that allows us to extend the service of the spacecraft. But we can envision future services that would not just be life extension but replacement of failed components or even changing the mission. There are a lot of ideas on how we could design satellites to enable those services. Today we don’t have those concepts rolled into the satellite design. I think this requires an industry effort to standardize certain features so we are more easily able to expand the service scope in the future.
Can you give some specific examples?
Think about consumer products, where USB connections all have the same interfaces so you don’t have to buy a special type for every computer or cellphone. If we can have similar common interfaces for satellites, that makes the job a lot easier.
We can envision an interface that is able to provide power or data or a lot of different things. That could even allow us to change the type of mission of the spacecraft. The options are endless.
What is Intelsat doing to prepare for the MEV-1 mission?
Intelsat and Orbital ATK have been working together developing a concept of operations for operating these two spacecraft together as one. We also have done significant work on the whole design of MEV. We’ve been working pretty closely with Orbital ATK in developing their capabilities and how we are going to operate the spacecraft.
Orbital ATK recently finished compatibility assessments with Intelsat-901, the first spacecraft MEV-1 is going to be docking with. It was very successful. We have various key design reviews coming up and have been working really well as a team.
Have you decided on the use of MEV-2?
Yes, we have but I am not going to disclose what it is.
Do you have plans for more satellite-servicing missions beyond those two?
Yes, we are constantly looking at potential options. We are also looking at additional capabilities. It’s not just limited to MEV. We might be looking at refueling and other concepts for life extension.
Do you see advantages to MEV’s approach over what Maxar is doing with refueling and separating?
I think each vehicle has its own advantages and disadvantages. When we signed up for MDA’s satellite-servicing effort a few years ago, their concept was refueling instead of docking. The MEV approach is a more conservative technology choice. For us, because it is still relatively new, we want to be more conservative, but it does not preclude us from getting refueling with a Maxar-type of system.
Why do you consider the MEV approach to be more conservative?
To refuel a satellite on orbit, you have to get into the inside of the spacecraft, open up fill and drain valves, put in fuel — which is very volatile — and then seal up all the interfaces and separate from the spacecraft. There is significantly more operational complexity that’s involved in refueling whereas MEV’s approach is to go and attach to your client’s spacecraft and that’s it. Then MEV takes care of station keeping and attitude control. It’s a much simpler concept.
At Space Tech Expo in May, Intelsat’s vice president for satellite operations and engineering said he would like satellites to be able to function indefinitely. Do you agree?
We have some satellites that have been operating for 25 years and are still providing very valuable service to our clients. To the extent that the service is relevant, then it could stay there for a long time. There is a fine trade between having a spacecraft for a long time and not being able to provide the kind of services that are current in today’s market.
Last year, three satellites near or past their 15-year design lives malfunctioned in GEO and became space debris concerns. How do you decide how long a satellite’s life can be extended without putting its orbital neighbors at greater risk?
We have full telemetry so we know the health of the spacecraft. Our typical experience is that the spacecraft has to be limited due to fuel life. That’s the primary limitation. There are exceptions when you have anomalies and potentially could have catastrophic failures but those are few and far in between. We tend to have good assessments of which spacecraft are at risk and we make decisions accordingly.
SpaceNews.com

Source: Why Intelsat’s going with life extension over refueling