The days of dumping communications satellites into graveyard orbits simply because they are out of fuel are coming to a close, with implications that go beyond the revenue streams of the big satellite operators.

ViviSat, a satellite-servicing startup developing life-extension vehicles for end-of-life commercial communications satellites in geostationary orbit, has booked two customers for three missions, and expects to start building its specialized spacecraft by the end of 2014. The company hopes to advance beyond a “jet-pack” lashed onto the target's kick-motor nozzle and start using robots for refueling and simple repairs. After that the imagination is the limit, with robotic spacecraft that do maintenance, repair and overhaul (MRO) to keep satellites in business indefinitely.

“It has really gone from . . . 'could this be done' to 'when are you going to be ready,'” says Bryan McGuirk, chief operating officer of the ViviSat joint venture of ATK Space Systems and U.S. Space.

The company has “a number of clients” who may reserve a fourth “Mission Extension Vehicle” (MEV), McGuirk says. Once that mission is booked, he says, ViviSat will pursue its final financing and begin bending metal. Given the expected start this year, a first flight should come about three years later, according to CEO Craig Weston.

McGuirk declines to identify the satellite operators that have reserved MEV missions, or the amount of financing ViviSat needs to build spacecraft and begin operations. ATK will assemble the MEVs at its Beltsville, Md., facility, where a robotics laboratory has recently been upgraded to perfect the software needed for rendezvous and proximity operations (photo).

Joe Anderson, director of MEV services at the ATK unit, says the vehicle will be designed to approach a customer's spacecraft using optical sensors and a laser ranger to navigate. At the end of its approach at “centimeters per minute,” it will halt about 1 meter away from the target's apogee kick motor, extend a probe into the motor nozzle to grapple the spacecraft, and pull it toward the MEV until the servicing spacecraft's four “legs” brace it against the target's launch adaptor ring.

The resulting connection will be purely mechanical, with no electrical or data hook ups. The MEV will take over the customer-spacecraft's station-keeping and attitude control for as long as 15 more years. There are “more than 200” satcoms that will run out of fuel by 2022, and are candidates for life extension with the addition of an MEV.

“If we did not exist, they would just run out of fuel,” McGuirk says. “The current solution is they would purchase a new satellite, and on average that costs $300 million.”

Instead, McGuirk says, customers will be able to lease the spacecraft to avoid the up-front capital costs, opening up a new kind of market in geostationary orbit. ViviSat uses its laboratory mockups of a full-scale MEV and a generic commercial satcom to demonstrate its technique to potential customers and insurers, according to Weston.

Plans call for the first MEV to demonstrate its capability in the graveyard orbit about 300 km higher than the geostationary arc occupied by operational satcoms. It will use one of the inaugural customer's satellites that has reached the end of its fuel supply but has been kept alive for the test, before descending to the target bird.

Weighing approximately 2,000 kg at launch, with a body measuring 5 X 6 ft., the solar-powered MEVs will ride one or two to a launch vehicle, and carry enough fuel for the rendezvous, berthing and extended operations on more than one satellite. McGuirk says ViviSat's concept has been “widely accepted” by insurers, but the prospect of proximity operations raises eyebrows among civilian and military spacecraft operators who worry about collision, tampering and radio-frequency interference.

“Any satellite can be used to tamper with another satellite, whether it is interference [or] whether it is collision. Any satellite is potentially a space weapon,” argues Dennis Wingo, an engineer and writer specializing in private space ventures. “How do you then constrain the growth of satellite servicing when any satellite can be used in that same manner?”

In fact, spacecraft servicing is receiving a lot of positive attention from the U.S. government, even as the FAA wrestles with setting up safety and other regulations for emerging commercial-space activities. NASA is running an experimental testbed on the International Space Station to evaluate robotic techniques for satellite servicing, and the Defense Advanced Research Projects Agency is pushing a three-pronged effort called Phoenix that hopes to build specialized spacecraft in orbit from modular “satelets.”

NASA will make its future large space observatories robot-serviceable, says Ben Reed, deputy project manager in the Satellite Servicing Capabilities Office at Goddard Space Flight Center. Eventually satellite manufacturers can take a similar approach, he says, despite Wingo's contention that “the incumbent satellite manufacturers do not have any vested interest in doing this.”

Before they start building-in serviceability, Reed says, manufacturers can make use of target decals and Velcro thermal-blanket closures to make their spacecraft easier to find and fix.

“Robotic servicing in GEO is inevitable,” he says. “We have experience over three-plus decades of human and robotic servicing in orbit, going all the way back to the parasol on Skylab”—a cooling sunshade astronauts installed in 1973. c