Graveyard Scavengers

Imagine virtual reality game, where characters are human like robots which live in the central station, without any humans on-board. To survive perils of space, they need to scavenge...not asteroids, but pieces of satellites brought to this central station. Power supplies, processors, boards, and even remnants of fluids become rare commodities. They need to assemble failing solar panels to keep their station powered. They don't have enough cooling fluids but need to keep the temperature stable. And they need to scavenge any suitable propulsion material to enable their ships to go out and search for more satellite parts.

Occasionally, mother ship from Earth brings them new supplies and new spare parts - but these are rare events, often insufficient to make them running. So participants are forced to trade parts, knowledge and work in order to achieve any goal. Some of them can buy a ship, and try scouting and bringing back a lost satellite. Others can risk work in open space, taking the incoming cargo apart. Or they could scout around the station, catching any drifting items as they float away from the station.

And imagine that such game could be linked to a true reality. Where players would control their robotic avatars on a robotic space station. Could this be done today? And could be done with reasonable costs? Is there a place in space, where we have a lot of easily accessible defunct satellites? Readily available telecommunication infrastructure? Frequent launches?

There is such a place, near the most valuable orbit around the Earth - geosynchronous orbit. It is called graveyard orbit, just a few hundred kilometers above. It is a set of orbits where old, decommissioned geosats are moved at the end of their commercial life.Then they are safed by venting any pressurized gasses, fluids an by emptying batteries.Typical geosat has a lifetime of 15 years, mostly limited by fuel requirements for station keeping. At the end of that period, satellites are moved to graveyard orbit using just 11m/s of delta-V.

Numbers are staggering. There are 20-25 satellites launched to GEO ANNUALLY. Which means that there are roughly 20 ride-share opportunities per year (similar to ISS). If we assume average end-of-life mass of 2000kg per satellite and 20 decommissioned satellites per year, that is 40t of mass disposed to graveyard orbit each year. Total mass of  disposed satellites is nearing 1000t of useless garbage, which represents long term risk to active space assets.

Big issue in every space debris cleanup/removal plan is who is going to pay for it. Graveyard orbits do not provide long term solution, they are just a way of temporary piling up the garbage. Any collision in graveyard orbit would likely created debris that would put any GEO sat in great danger. Especially since ground based radar tracking cannot detect larger objects at that distance.

One possible solution is to pile up all graveyard satellites together, in a fixed, rigid structure. That way, instead having large number of heavy independent objects, there would be just one which would accept all "GEO" junk. Most satellite owners would be glad to get rid of any potential liabilities. But the big issue is who would be paying for the establishment and operation of such facility. Government led effort and imposition of any "space-tax" would be hard to establish on the international level.

By adopting "less serious" approach of using gaming/entertainment approach to space business, such approach can be done in gradual and commercially acceptable way. How could such an effort be bootstrapped? First step would be redesigning some of space related vehicles to act as a long term station hub (OATK Cygnus seems like a perfect candidate). It has power, attitude control, electronics, pressurized hull, communications already as part of the standard package.

The second part is the payload - dozens of robots, built from replaceable parts, that can function both in pressurized volume and in open vacuum of space. Outside hull would be equipped with robotic arm, and some kind of docking module. Other tools would be 3D printer, metal cutting tools, etc.

Primary mission: dock with defunct satellite in GEO orbit, capture it and move to graveyard orbit. Secondary mission: unleash the robot horde upon it. Then launch smaller resupply missions as ride-shares with other geosat launches. Robots would be tele-operated by consumers from Earth. The actual goals - how to (re)use existing "junk" would be left to the players in the game.

What about business perspective? Typical GEOsat mission ranges between 200 and 400 million dollars.  Cygnus CRS-1 per mission cost was around 240 million. In 27m3 of internal volume it could easily support 100 robots. Except hardware and launch, this type of mission would need extensive down-link requirements (over 100 HD channels), which perfectly fits into current capabilities of optical terminals.

On the sales side, providing a hundred robots for tele-operation at $100 per hour leads to 87 million dollars of yearly revenue. That excludes any other possible revenue stream. Many MMORPG type of games have sustained concurrent user activity measured in tens of thousands. So providing access to real thing (control of a real robot in space environment) should justify much higher pricing point. For most space enthusiasts that would be the closest thing to space exposure they can hope to experience. Market potential can probably scale to thousands of concurrent players.

After the initial mission, this robotic station would move to the next target, since any remaining target is very close (measured in needed delta-V). Solar panels could be recycled to provide additional power. Batteries would not be needed much. Since the Earth's shadow is small at that distance, and there is no requirement for station keeping on the same place relative to Earth, it can be easily avoided.

After a few captured satellites, it would be no more cost effective to move whole station to the satellite. Instead, new scavenger ships (scaled down version of the initial module), could depart the initial station to fetch designated target and bring it back to the station. With this approach, whole "virtual economy" of GEO graveyard station would be jump-started. Imagine that: thousands of players around the world would control tiny robots on a 1000t space station. Tiny space ships would depart and return to the station with the cargo. And not only that. What if some GEO sat stop functioning suddenly? Why not dispatch a rescue mission of mini-robots already near by? Or to install new equipment? Or to refuel? Would it not be easier than building a custom spacecraft, procuring GEO launch, waiting three years until anything happens? No wonder that in-space satellite repair missions did not took off for commercial payloads. In this model, all needed equipment might already be near the defunct satellite. If not, just add it to the next resupply mission, that leaves in a few months.

In that world, why would commercial satellite operators require fool-proof, fully redundant, heavily tested design that will function flawlessly for the next 15 years? Maybe, knowing that experienced hands-on repairmen (actually their robotic avatars) exist "next door", launch simpler satellites which would cost much less to begin with?

This approach would provide many space enthusiasts the fulfillment of their dreams. At the same time, it would reduce potential debris problem in GEO and reduce cost of GEO based telecommunication satellites to compete against onslaught of LEO constellations.


Comments

Popular Posts