Spaceflight Formation Flying Test Bed Takes Off

coondoggie writes "Getting complicated systems onboard a single spacecraft to operate as one integrated unit can be hard enough, but some space agencies are trying to address the challenges of getting multiple spacecraft to fly in formation and operate together as one unit. Such challenges are exactly what a new European Space Agency lab in the Netherlands is set to address. The test bed addresses crucial operational factors for formation flying, including mission and vehicle management, guidance navigation, dealing with faults and communicating between satellites."

Comments

Will we be seeing...

[munozdj]

The Space Angels?

DARPA has been investigating this concept a while

[FullBandwidth]

Their most recent direction has a decidedly "open source" feel to it ... and you still have a chance to submit proposals: http://www.darpa.mil/news/2010/SystemF6NewsRelease.pdf

It will be a critical ability.

[Jane Q. Public]

Traveling in formation is essential if you want multiple spacecraft to travel together. It's not like airplanes which can each have a pilot at the controls. Automatic formation will be absolutely necessary to avoid collisions.

But I want to berate the author of TFA, because the issue is traveling in formation, not "flying". Spacecraft do not "fly". I'm not nitpicking; there is a pretty big difference. It's just plain intellectual laziness on his part.

Re:It will be a critical ability.

[geekoid]

Man, you must just about have an anurism every time you read "space flight".

Bottom line,. people will use the term fly. get use to it.

Re:It will be a critical ability.

[starless]

Spacecraft do not "fly". I'm not nitpicking; there is a pretty big difference. It's just plain intellectual laziness on his part.

No. This is a standard term. Please check before criticizing others if you don't know the field.
See e.g.
http://dst.jpl.nasa.gov/

Re:It will be a critical ability.

[AJWM]

Spacecraft do not "fly". I'm not nitpicking; there is a pretty big difference. It's just plain intellectual laziness on his part.

Nope, ignorance on yours. Spacecraft do indeed fly. Flying has nothing to do with wings or aerodynamic forces, it has to do with moving without touching the ground. There are certainly other terms for how spacecraft move -- which depend on the particular spacecraft and what they're doing -- but even pure ballistic flight (aka "orbit") is still flight.

Re:It will be a critical ability.

[geekoid]

what do you expect from a girl~

zing! or maybe BA-ZING~

Re:It will be a critical ability.

[HeLLFiRe1151]

So when swimming under water, you're actually flying under water?

Re:It will be a critical ability.

[Jane Q. Public]

Bottom line: people will cheat you in your life, too. Get used to it.

If it's wrong, why should I just "get used to it"? What, you don't think setting things right is worthwhile?

Re:It will be a critical ability.

[Jane Q. Public]

Okay, I will concede that in the dictionary I consulted, that use was indeed listed... in the 5th meaning of the word. The first is still "to move through the air using wings."

Re:It will be a critical ability.

[Sulphur]

So when swimming under water, you're actually flying under water?

Especially Penguins fly under water.

Re:It will be a critical ability.

[ErkDemon]

"Traveling" is too vague. Spacecraft "travel" when you trundle them to the launchpad on trucks, and if we're doing astrometrics, motion is relative and the concept of whether something is "traveling" or not becomes complex. You're "travelling" right now as the Earth orbits the Sun.

If we want a term to describe orderly controlled non-surface relative motion through a rarefied medium, "flight" isn't bad, "fly" has the advantage of only being one syllable, and we already have the concepts of "powered" and "unpowered" flight. Sure, it's not aerodynamic flight, but there are other cool environmental things to make use of, like the gravitomagnetic fields of passing planets, for slingshotting.

Re:It will be a critical ability.

[geekoid]

In a lot of respects..yes.

Re:It will be a critical ability.

[JustOK]

Especially Penguins fly under water.

in theory. There's no mathematical proof that penguins exist..

Re:It will be a critical ability.

[ErkDemon]

Well, if we're going to be picky, if you check what your dictionary defines as a "wing", you'll probably find that the corresponding first definition is something to do with the flappy things on birds. Dictionary.com doesn't mention the "aeronautical" definition of "wing" until definition #9, so by the argument you used, we probably shouldn't call what aircraft do "flying", either, because their "wings" aren't biological structures, and don't flap.

AFAIK, "spaceflight" is pretty much the standard term for the technical subject, for instance, here's an introductory NASA page on the subject.

Re:It will be a critical ability.

[geekoid]

It's not wrong. however;

Because we are talking about a common use of a common word being used in the commons. Not in scientific literature. It does no harm, and causes no confusion. It's not being used to 'teach the controversy' .
It's like spazzing over the term 'hacker'.

"What, you don't think setting things right is worthwhile?"
tsk, tsk. Seriously? you jump to a logical fallacy? I've read your posts, you're smarter then that.

In THIS case, if you don't 'get used to it' you will spend a lot of time frustrated.

OTOH maybe it's just age. I have fought so many technically correct*, but useless in any practical way battle over terminology I just don't see it worth while for a term that doesn't hurt anyone.

"*technically correct -- the best kind of correct." Bureaucrat #1.0

Re:It will be a critical ability.

[Anonymous Coward]

You appeal to vanity? I've read your posts, you're smarter than that.

Re:It will be a critical ability.

[Idiomatick]

"a surface used to produce lift for flight through the atmosphere - or occasionally through another gaseous or fluid substance." was the first defn on google search for 'wing'.

Re:It will be a critical ability.

[AJWM]

Water could be considered really, really soft ground, so not necessarily. But as another poster observed, what penguins do underwater is more like flying than anything else.

Re:It will be a critical ability.

[AJWM]

Okay, I will concede that in the dictionary I consulted, that use was indeed listed... in the 5th meaning of the word.

Doesn't matter whether it was the 5th, the 1st, or the 97th, it invalidated your statement that "Spacecraft to not 'fly'". If you're going to accuse somebody of intellectual laziness, you'd better have done your homework yourself.

Re:It will be a critical ability.

[Geirzinho]

Poor intellectual judgement on his part? It's the accepted term. Just look at
http://spaceflight.nasa.gov/home/index.html, and the about 1,430,000 other results just at nasa.gov pages.

Re:It will be a critical ability.

[dominious]

From wikipedia:

Flight is the process by which an object moves either through the air, or movement beyond earth's atmosphere (as in the case of spaceflight), by generating lift, propulsive thrust or aerostatically using buoyancy, or by simple ballistic movement.

Re:It will be a critical ability.

[AikonMGB]

Well, if you believe that planes fly through the air, then what is different about water? Air and water are both fluids, they just have different densities. Think of a submarine -- it has control surfaces just like an airplane.

The term "flight" is widely used in the space industry, regardless of how appropriate the original meaning was at describing the motion of spacecraft and satellites (recall that early rockets didn't even make it to orbit, but still passed the edge of "space").

Aikon-

Re:It will be a critical ability.

[treebeard77]

good point. however, it makes me wonder how applicable the recent software which mimics how birds and fish travel in flocks/schools will be to this problem

Re:It will be a critical ability.

[ZygnuX]

"Or by simple ballistic movement" That means that people can fly unaided, for very short amounts of time?

Re:It will be a critical ability.

[WolfWithoutAClause]

Do arrows fly?

Do stones?

I think most people agree that they do when they are thrown, even though they may have no propulsion and no aerodynamic lift.

How is this different to what spacecraft do?

It isn't. They are all examples of ballistic flight.

Re:It will be a critical ability.

[Jane Q. Public]

No sh*t, Sherlock. That's why I used the word "concede".

awkward headline

[jewishbaconzombies]

At first glance all I can think of is Serta Sleepers being thrown into space.

Liftoff! We have liftoff of Stainy One, ushering in America's new in-orbit dumping of unwanted mattresses. Next month will see the launch of Smelly Two.

I recommend you use control type A or B

[game kid]

One way they can address this is with indiscernible warnings from fellow pilots.

formations

[nimbius]

arguably are not relevant in space...or at least i fail to see the relevance from any standpoint other than purely tactical. The only thing spacecraft require
is an understanding of eachothers location, and an understanding of the location of objects around them. a significantly well developed computer program
would certainly be capable of tracking this information

it just shouldnt be capable of singing daisy.

Re:formations

[geekoid]

it's incredibly complex, and will be needed for robotic swarms. Imagine trying to keep 1000 robots in formation with each other without have an unexpected event start to cascade thought the swarm and cause a formation collapse.

Re:formations

[cynyr]

why do they need to be in tight formation? a voltron style bot? well i guess something like each bot has a mirror, and they are making a huge telescope, but i fail to see how thats better than just using a rigid structure in the first place. bolt it together so it can be put together by 6 bots, and then taken back down the same way, and be hauled "up" in pieces.

Re:formations

[butalearner]

[Formations] arguably are not relevant in space...or at least i fail to see the relevance from any standpoint other than purely tactical. The only thing spacecraft require is an understanding of eachothers location, and an understanding of the location of objects around them. a significantly well developed computer program would certainly be capable of tracking this information

Disregarding the fairly major difficulty of accurately determining the location of objects around them (not to mention the nontrivial bit of understanding its own location), they also need to have an understanding of the velocity and acceleration as well. In space, moving in one direction doesn't mean what you think it means. If one accelerates in the direction of motion, it will take longer to orbit the Earth. If two satellites at the same altitude are traveling parallel to each other in the same direction, they will collide in 1/4th of an orbit. There's a reason that there was a spacecraft recently whose sole purpose was to demonstrate autonomous rendezvous.

If that still sounds simple, now add a dozen satellites, and realize you can't just make them fly in the same formation all the time. The fuel requirements for stationkeeping of the outermost satellites would be astronomical. You have to minimize course corrections if you want a reasonable mission lifetime. Or carry a great deal of fuel, which can easily defeat the purpose of using smaller spacecraft in the first place. On top of that, when you need to apply collision avoidance maneuvers, you have to make sure you don't put yourself onto a collision course with the other 10 satellites.

As for the purpose of formation flying (note we're talking about the cluster kind - the trailing formations are fairly straightforward):
Wikipedia

Re:formations

[butalearner]

Increasing the distance between mirrors increases the effective radius, while decreasing the distance increases the light collection capabilities. A cluster may want to do either depending on what it's trying to image.

Re:formations

[John Hasler]

but i fail to see how thats better than just using a rigid structure in the first place.

Rigid structures are massive.

bolt it together so it can be put together by 6 bots, and then taken back down the same way, and be hauled "up" in pieces.

Many heavy and therefor very expensive pieces. Much, much, much cheaper to use ion engines, laser interferometers, and clever software to maintain relative position.

Re:formations

[John Hasler]

Increasing the distance between mirrors increases the effective radius

Yes.

while decreasing the distance increases the light collection capabilities.

What makes you think that?

words that conjure images

[Junior J. Junior III]

Spaceflight Formation Flying Test Bed... wait wasn't that a Pink Floyd album cover?

Re:words that conjure images

[Anonymous Coward]

When I first read the title, it brought (rather confusingly) this to mind.

Put out SPS?

[xenapan]

Space positioning system?to track the satellites in orbit of earth!

Re:Put out SPS?

[by (1706743)]

This could certainly be done with pulsars, though I think the resolution would leave something to be desired.

Prior Art from the 80s

[RobK]

Wasn't this solved in Galaga?

Re:Prior Art from the 80s

[JustOK]

Space Invaders!

Re:Prior Art from the 80s

[scottrocket]

An unauthorized Star Fleet academy graduation exercise! Or was that the nineties?

Gemini

[YrWrstNtmr]

Um, wasn't that the purpose of the Gemini missions? To prove and define the concept of 2 or more spacecraft flying in formation (and docking)?
And later unmanned Progress craft flying in formation, and docking with, the ISS.

Didnt E.E. "Doc" Smith already solve this?

[Anonymous Coward]

At the very least, they should name one ship the Directrix.

Is it only me?

[allaunjsilverfox2]

I suddenly had a image of rockets being attached to a bunk bed and being launched. Am the only one that got this image?

re: Flying Test Bed Takes Off

[randy of the redwood]

Flying Test Bed Takes Off - giving a whole new meaning to the mile high club.

Sorry couldn't be bothered to RTFS

Nothing new

[photonic]

The article unfortunately contains almost no information, except for the fact that ESA wants to do formation flying and is developing some testbed. This is not news, since ESA has been studying missions involving satellites flying in close formation for more than 10 years: for example the Darwin mission, which would have flown some telescopes at a few hundred meters to do optical aperture synthesis for detecting extra-solar planets (mission appears to be shelved right now) and XEUS which is a 'standard' 100 meter long x-ray telescope, but instead of physically connecting lens and focal plain it consists of 2 spacecraft that are virtually connected by a system that measures the mutual positions.

I had the pleasure of getting a tour on the JPL campus a few years ago, which to me seemed like a place where they build nothing else than super-cool over-engineered testbeds just for fun. I probably saw some early version of this testbed. They had a large hall with a smooth floor over which the 'satellites' could slide on air-bearings (3 degrees of freedom), on which a vertical piston was mounted (1 DOF) and finally an over-sized ball-air-bearing for the remaining 2 tilt DOFs. This provides a platform that can move freely in all degrees of freedom, which would carry a satellite-simulator consisting of small air-jets and a shitload of sensors to do the 'formation flying'. Very impressive, even if it was not operational at the time. If ESA would be starting now with their testbed, they would trail NASA by at least 5 years. Lets hope they have been doing something in the meantime.

Re:Nothing new

[Morty]

NASA has a number of Earth-observing satellites already in orbit that do formation flying as part of the so-called "A-Train". TFA mentions this, although it links to a PDF instead of HTML. See:

    http://en.wikipedia.org/wiki/A-train_(satellite_constellation)

Re:Nothing new

[photonic]

That is probably not the same kind of formation flying as TFA was talking about. At 690 km altitude, the A-train has an orbital velocity of 7.5 km/s, so the minimum separation of 15 seconds translates to more than 100 km of mutual distance. Although this is not really trivial to do and would probably require some daily adjustments of the orbits, it is more like 'flying several satellites in the same orbit', totally controlled from the ground. The missions I was mentioning operate within 1 km of each other and should fly with relative position accuracy of better than 1 mm, based on local sensors and active feedback using small thrusters that can actuate with a force of milli or even micro-Newtons.

I'm Dumb as a Stone

[b4upoo]

Apparently I must be dumb as a rock as it would seem to me that several jets flying information have the same problem as satellites traveling together. Speed, position and collision avoidance seem to be old issues to me. I wonder if the government actually farmed out money to grow a solution? Am I a dummy or what goes here?

Re: I'm Dumb as a Stone

[Moridin42]

Jets flying in formation have their own organic computers that require offline maintanence roughly every 18 hours. Spacecraft don't have the luxury of landing to let their pilots off, or for hauling months of food, or the means to keep their pilots from going insane with the monotony. Not if they're going to be financially feasible anyway. Hence.. automated systems for maneuvering and analyzing sibling craft position, as well as getting physically discrete systems to interoperate as a single platform.

Re: I'm Dumb as a Stone

[wagnerrp]

Aircraft have aerodynamic control surfaces to maneuver, spacecraft must do everything with reaction thrust. Not only do you have a limited amount of fuel, of which you cannot get more, but you have to worry about dousing others in the formation with your exhaust. Formation flight is generally for the purpose of some sort of phased array telescope, and you don't want to gunk up your optics with rocket fuel.

Re: Flying Test Bed Takes Off

[Colin Douglas Howell]

Flying Test Bed Takes Off - giving a whole new meaning to the mile high club.

Reminded me of the Flying Bedstead.

so it is what space powers did for real ..

[BigGerman]

.. back in 60s? http://en.wikipedia.org/wiki/Soyuz_7

Flying vs Falling?

[sjs132]

Since they are not using propulsion once they obtain an orbit, would it not be more realistic to call them "formation falling"?

Just a thought...

Re:Flying vs Falling?

[wagnerrp]

A satellite without propulsion is a dead satellite. LEO satellites require fuel for occasional boosts to prevent reentry. GEO satellites require fuel or else they will drift off station. Everything needs some reserve to push it out of the way once its functional life is up, and let other satellites take its place.

interesting

[db10]

My ex wife did a stint at nasa on this very subject, using controls theory or whatever

Something like the classified NOSS???

[Dr La]

The US Navy has quite some experience (decades, actually) with formation flying with their NOSS (Naval Ocean Surveillance System) SIGINT satellites (http://www.satobs.org/noss.html). The old one flew in tight triangular formations of three (quite a sight to see), the newer ones do it with two. They serve to pinpoint ships based on their radio communications.

Also, the Chinese appear to be experimenting with a similar concept (http://www.nasaspaceflight.com/2010/08/china-launches-military-satellite-yaogan-weixing-10/).

Here are two pictures I shot of two of the newer NOSS formations, NOSS 3-4 launched in 2007 and NOSS 3-2 launched in 2003:

http://i19.photobucket.com/albums/b176/marcoaliaslama/satellites/170109NOSS3_4.jpg
http://i19.photobucket.com/albums/b176/marcoaliaslama/satellites/131208NOSS3_2.jpg

Hasn't this been done?

[harris s newman]

Since before the moon missions, we have docked ships. I think that is multiple ships flying "in formation". Don't seem to understand the expense...

Flying in formation is easy

[Fear the Clam]

It's getting the "pew! pew! pew!" noises to sync up that's hard.

Alternative ways for manoeuvering than thrusters

[Dr La]

Actually, apart from reaction thrust you can use a 2nd way of manoeuvring in LEO orbit: adjusting your drag parameters.

Satellites in LEO still experience some drag from the outer layers of the atmosphere (this is why they decay if the orbit is not maintained by manoeuvres).

In theory, you can use that to adjust your orbit (e.g. by adjusting the attitude of the satellite so a larger surface points forward: or by temporarily increasing that forward facing surface, e.g. with adjustable or inflattable panels). It is rumoured that the US Navy NOSS satellites (see my comment elswhere in the comments to this topic) use manoeuvring techniques of that kind to maintain their thight formation

Not in Esa but in Sweden and France...

[Anonymous Coward]

There are two kinds of Formation Flying.

One just associates several Earth observation spacecrafts so that they pass above the same piece of ground roughly at the same time, gathering a larger set of observations (in different wavelenths, etc.).
It's an easy way, indeed you just coordinate the orbits through the ground control segments, and a more honest way of calling it would be "coordinated flying". This is the case for e. g. the meteo A-train in the US, and various other missions.

The other one is much more difficult and bring different outcomes.
It consists in actually servoing one spacecraft around another one, "in sight". Depending on the need and techno, the relative distance can be controlled to some cm, some mm, or microns, the latter through interferometric measurements.
Two spacecrafts actually flying in formation can create space instruments with very large sizes, for instance telescopes that otherwise would just be not launchable with present-day technology. This technology also is very interesting for tendering, or attacking, a target spacecraft, would it be to refuel it... or to blind its observation cameras, in case of need.
So, this technology -the real formation flying- is futuristic but quite interesting.
In this area, in spite of bold declarations and what is probably a sincere interest from their technology director, Michel Courtois, Esa just never managed to develop anything, which is probably why they now announce some ground testing thing, and a future small spacecraft, Proba 3, that will fly... someday.

The really nifty guys as of today are the Swedes, in association with the French, with their mission Prisma, where two initially connected sats do detach themselves and actually turn and manoeuvre, autonomously, one around the other.
Prisma was launched this summer, with a RF technology for formation measurement and control developed by the french CNES space agency onboard (the actual measurement hardware built by Thales Alenia Space, the -very nifty- supporting spacecrafts by Sweedish Space Corporation).
Since then, it does work perfectly, and is a wold premiere, unless nonpublic military tests happened before.
All the details are on the site from SSC: http://www.ssc.se/?id=5104&cid=17201
(a more general presentation of Prisma: http://www.ssc.se/?id=5686&cid=7611)

But, Europe being what it is, SSC remains a very small company; Sweden a relatively isolated country with reduced funding allowable to space developments; France, well, is the France of now, with a president far more interested in serving racist electors than having a vision of the future (which just blinds the national agency long-term ambitions, who won't fund Thales anymore), and so, it is quite predictable that the brilliant Prisma development, and associated know-how, will soon become a nice souvenir.

For the moment, go to the above urls, you'll get real photos, of a real couple of spacecrafts flying in formation.
This is today, not in Esa dreams, and paradoxically, it also has this dramatic flavor of those things bound to turn back to ashes soon.

(submitted AC for being dangerously close to all those guys)

Flying under water?

[Terje Mathisen]

Since I first learned to swim, I've always felt that moving around in a 3D environment under water is similar to flying.

Snorkeling on a reef is _very_ similar imho.

Terje