The military spends a lot of money on building communication satellites and sending them into space. Lots of them are still up there, long after they've failed or become obsolete.
Wouldn't it be neat to recapture and recycle the components, which are often still working, while also getting rid of all that space junk? The Defense Advanced Research Projects Agency (DARPA) thinks so, and it wants to use robots for the job.
The Phoenix program's goal is the development of technologies that can harvest the components of retired, nonworking geostationary earth orbit (GEO) communication satellites. Reusing those components, such as space apertures, solar arrays, and antennas, would slash the costs of building new ones. It might also speed their replacement, in the military's effort to maintain 24/7 global communication capability for soldiers on the ground.
In the proposed Phoenix program, robotic arms and end effectors can decouple an antenna from its retired military communication satellite and reuse it in a new satellite, saving money, maintaining global coverage, and cleaning up space junk. (Source: DARPA)
Very small satellites, or "satlets," would ride along during commercial satellite launches in a payload orbital delivery system (PODS). Separately, an on-orbit tender, or satellite servicing satellite, will be launched into GEO. When the tender arrives on orbit, the PODS will detach itself from the commercial satellite host and connect with the tender.
The tender will be equipped with robotic grasping arms that will remove a satlet and attach it to, for example, the antenna of a nonfunctioning or decommissioned satellite that it has harvested from the graveyard orbit. The result is a new satellite created in GEO that's ready to be deployed. The robotic arms could also replace parts on, and perform other service tasks for, satellites that are still functional. (Watch the video below showing an artist's depiction of the proposed tender salvaging a retired satellite's still usable antenna.)
Several different technologies are needed for the Phoenix program, and many are still in development. As part of the project's first phase, DARPA has selected Honeybee Robotics Spacecraft Mechanisms to develop two different types of new telerobotic end effector prototypes for satellite rendezvous and docking. End effectors function as the hands of a robot arm, or manipulator. The prototypes will be designed to enable a servicing satellite to dock with and manipulate communications satellites in GEO.
Other robotics-related technologies being developed for the program include industrial robotics and tool changeout mechanisms, as well as remotely operated surgical robotics tools and imaging systems.
Love, love, love this idea. Just this weekend, I was up in the mountains of New Hampshire with my family and we were scoping out the meteor showers in the big, big sky. We were noticing all the satellites and got to talking about space junk and how crazy it is that humans not only litter their earth, but now space as well. Leveraging robotics to clean up our mess is a beautiful thing.
Love the video showing how this would work. Great use of robotics, as well as good use for the used satellites. Looks like recycling has expanded beyond our atmosphere.
The comments about space junk on some of the stories I wrote on using composites in satellites piqued my interest in the subject, so when I saw this announcement I grabbed it. Rob is right: the idea of recycling has reached beyond Earth's atmosphere.
What's interesting is the extent of the space junk. There are thousands of pieces, including an astronaut's glove. I'm sure there's a great backstory there. And all of those pieces are tracked so they know when a piece might slam into the space station. One piece came close to the space station not long ago.
I didn't get to see the video yet (at work), but I am wondering how easy or hard it is for parts to be scavenged from one sat and then applied to another.
Even on sats of the same type there could be hardware and alignment issues. We make small changes to print packs all the time. I'd hate to see a bot going from one out of service sat to another searching for a hole/pin alignment match. Or filing out a hole to get a fit... ; )
Also, a lot of things might be potted in place, or otherwise hard to remove. Perhaps a tile knife, some outer space approved duct-tape, and a spool of bailing wire would be a handy addition to the tool box.
On the other hand, if it hasn't already happened... a plug and play, snap in place assembly line-one size fits all design regimen in the future could insure a high rate of retro-booting.
We made 100+ battery packs for a sat network some years back. They were all identical. If some of those are bricks, and other sats have been shut down for other reasons but the batteries might still be good... that might be a worthwhile swap depending on how the 2kg packs were installed.
I like your plug and play idea, Ralphy Boy. And if that fails, I'd opt for the duct tape. There are very few things duct tape won't fix -- except a leak in a swamp cooler hose, as I found out recently.
I agree, Rob. The video is phenomenal. It's amazing how easy the docking procedure looks on the video, considering that those satellites are moving at about 3 km/sec.
I agree about the speed, Chuck. It all looks like it's in slow motion. And maybe in some sense it is. But it must be a technological wonder to match speeds and connect like that. Just a slight speed difference and you have crash.
The video, of course, is a simulation, so things may look a lot easier than in reality. OTOH, it's amazing how we've been doing accurate synchronization in 4D for decades, including when human lives are at stake.
Yes, but I think the simulation is probably pretty accurate. We've seen the same type of seemingly slow motion hookups with the space station. It's quite amazing.
The slow speed shown in the video is typical of zero G/microgravity maneuvers: it's to make sure they don't richochet off of each other and fly out into the great beyond.
You're right about that motif, Ann. I remember one of the first space movies I saw as a kid in the 1950s. An astronaut was outside the spaceship doing some maintenance and bumped into something outside the ship and it sent him flying, tearing his tether and sending him out into space spinning with no oxygen. Probably pretty accurate.
The astronaut-outside-the-spaceship motif is the classic scenario of the opportunity for that disaster. I've seen it in many movies, as well as learned about the dangers with real astronauts.
Yes, I love that motif. It's one of the fascinating aspects to science fiction movies, the actual science. So I was thrilled when Apollo 13 came out. Here was an exciting science fact movie -- the ultimate Sherlock Ohms.
Is it complete science fiction that in movies they wear magnetic boots or would it be reasonable to use electromagnets to make sure items don't bounce away from each other? Would it make sense to save parts in an orbit higher or lower than geosynchronous and count on the different angular velocities account for most of the positioning?
Just imagine the wealth of failure analysis information available from recovered satellites! On the one hand this would provide a wealth of information to future builders but it also would justifiably scare the heck out of everyone who ever made a satellite that hasn't yet burned up in re-entry. There's a whole lot of really proprietary information floating around out there. Imagine the US permitting the Russians (and Chinese and Indians and Pakastanis and . . .) to perform detailed failure analysis of technology and software used during the cold-war. All those "weather" satellites with gamma ray detectors and high resolution photographic assemblies. This could start a whole other space-race of countries (and companies) rushing to recover their satellites before anyone else did.
bob, good point. Since the "junk" is getting recycled in space and not returning to Earth, I wonder if DARPA, or NASA, is considering equipping Phoenix (the tender) with telematics of some kind that can send such data back for analysis. And since Phoenix is aimed at US military comms satellites, maybe DARPA is thinking preemptively about protecting its IP.
The ability to do failure analysis on this reclaimed "junk" should be a no brainer. There would be a wealth of really critical engineering data to be mined that could only help improve future satelittes and other related products.
Deja vu... Didn't someone just have a space shuttle program that was supposed to be able to capture and repair satelites in orbit or bring them back to earth for reuse?
You'd think that if you can track with any degree of precision where all this LEO junk is, you could use an intelligent satellite to catch up these items and give them a "tap", enough to destabilize them and cause re-entry. I know there's an initiative to require all satellites to be equipped with some de-orbit mechanism so that when they reach end of life they don't become just another piece of flotsam out there. I wonder how long it would take for this stuff to re-enter on it's own. Safe to assume that with all the stuff that's up there now, not anytime soon.
How about cleaning up our oceans. Millions of tonnes of junk have collected in the middle of our oceans. Surely an economical means of collecting this could be found. Much of it, I assume, is plastic which could be recycled.
Now that is the best idea of all! We have sunk tons of steel and aluminum, plus who knows how much plastic and even wood that could be salvaged without having to use space-faring technology.
However, space does need to be cleaned up. There is a lot of hazardous material "floating" around up there. I don't want a skylab full of nukes and garbage coming down on my head in the middle of the night. Nor do I want to have a high risk of being smashed by Russian/American/Chinese/European/Iranian/Pakistani/N. Korean/Japanese/Texan flotsam and jetsam if and when I decide to venture into space with my junkyard-built touring rocket. Yes, let's get space cleaned up!
I meant floating junk. Space junk could be "kicked" into a decaying orbit to land on a vacant lot in NY ! sorry, I meant N. Canada, Russia, or central Oz. ... somewhere that what little remains could relatively easily be salvaged, rather than dumping even more junk in the sea.
@Shane: Love to hear more about robots cleaning up the junk on the ocean floor as well. My guess is there's probably more stuff to clean up in the deep waters than out in space.
@Beth, it is said that a teaspoonfull of sediment, from any bit of sea floor on the planet, will contain visible pieces of plastic. A shocking reflection of our habits IMO.
I know that there are bacteria that consume iron(very slowly), and oil, but not sure about polymers.
@sbkenn: On the subject of plastic contamination in the oceans, Donovan Hohn's book Moby Duck is a fascinating read. He tried to track the journey of 28,800 bath toys that fell off a container ship. I highly recommend it.
There are a few polymer-eating bacteria, although so far I don't believe any have been corralled to harvest plastic from the oceans. I'd love to find out differently. Anyone know?
There was a marvelous TV show for a short time with Andy Griffith who was a junkyard man who built his own space ship to go and "harvest" the space junk left on the moon. I guess someone finally watched the old show and put a plan together. Kudos to Andy! :-)
I do find that now with all the sats floating around dead and possible interference with GPS units and C3 sats that DARPA is looking at the junk. 25+ years ago some of us were looking at automated ways to do just this but found more roadblocks than a prison break. Even if we had eveything on the launch pad, NASA and the Govenrment were not going to let a private group launch. Things have changed some and hopefully enough that we can get the junk cleaned up.
I remember the program. It came out about 5 years after the design work had begun. My parents thought we were working on the show instead of the real thing.
Everyone knows Mayberry was built on a series of underground missile silos. Barney has a Ph.D. in physics, and Andy was a nuclear propulsion expert. Everyone knows that!
Adding a dash of relativity... As I sit here at my Chromebook, I'm spinning on the surface of the earth at nearly 0.5 km/s. We are all (including the geosynchronous satellites) orbiting the Sun at 30 km/s, orbiting the center of the Milky Way at 250 km/s, and flitting among our local cluster of galaxies at 300 km/s -- for a grand total velocity of over 580 km/s. I'm not sure how I'm able to keep my coffee from spilling on the keyboard.. =]
The Hollywood motif that comes to my mind is Transformers or more specifically Star Trek: The Motion Picture in which Voyager 6 was repaired by a race of machines to become V'Ger, a machine that grew by assembling salvaged parts into itself. It is also suggested that V'Ger was responsible for creating the race known as the "Borg".
While we develop the use of satellites in the creation of SkyNet, now we have to contend with a DARPA initiative to create the Borg. At least we are not genetically modifying apes... no wait...
Cute exercise in Gallilean relativity, but why did you add all those velocities as scalar quantities? Unless thye are all in the same direction, you need to add them vectorially. Still, what's the point? For the space junk problem what counts is the velocity of a piece ralative to a satellite with which it might collide.
Ann, great article--as usual--great job. This is one subject that really interest me and I certainly applaud DARPA for taking a look. NASA tells us the following about space junk:
The overwhelming number of particles are smaller than one centimeter; i.e., 0.39 inches, but others are of considerable size. Estimates are as follows:
· 1,500 pieces of debris weighing more than 100 Kg or 200 pounds
· 19,000 pieces of debris measuring between 1 to 10 centimeters; 3.9 inches
· An unestimated number of particles, mostly dust and paint "chips" resulting from collisions that have occurred with larger objects also orbiting. Some "guesses" put that number into the millions.
For the most part, the debris can be categorized as follows:
· Jettisoned garbage from manned spacecraft, purposefully disposed of into lower earth orbit
· Lost equipment; i.e. cameras, tools, measuring devices, fabric hold-down straps, nuts, bolts, cotter pins, etc.
· Debris from collisions tearing apart structures either jettisoned or lost
· Rocket boosters that orbit yet remain in space. Some, over time, experience decaying orbits, eventually falling to earth.
With at least fifty nations participating within the space environment, the amount of debris can only lessen but not be eliminated. At the present time, over 20,000 pieces of debris are being tracked by these fifty nations. Let's hope DARPA is successful and we can lessen the expense of space exploration.
bob, thanks for quoting that info from NASA's site on space junk. It's amazing how many small particles there are, but scary how many large ones weighing more than 200 lbs are flying around.
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