Origami Plane to Fly From the Int. Space Station

SK writes "The University of Tokyo and the Japan folded paper (origami) plane society hopes to fly a paper airplane from the International Space Station to Earth. The plane will be 30-40cm long and weigh about 30 grams. A University of Tokyo research group has successfully designed a special paper plane model that was able to withstand a Mach 7 high velocity stream for 10 seconds. The experimental plane was about one-fifth the size and withstood temperatures as high as 300C without burning up." Unfortunately for most of us reading this, the original source is all in japanese.

flip?

[192939495969798999]

won't the paper flip when it starts to hit air, and burn up? How do you get a paper airplane to get to mach anything? I know how to make a very fast paper airplane for hand throwing, but it only goes maybe into the low 100 range... I never clocked it, though. Still, I think it would flip before getting that fast.

why not metal foil?

[G4from128k]

I would think that a metal foil would provide a better "paper" for the plane. Not only would it resist higher temperatures, but it would conduct heat from the hot side to radiate heat on the upper side. Chemically etching the foil on the upper surface to make it black would also help radiate heat. Finally, a metal foil plane would have a higher radar cross-section so it might be possible to track the trajectory and recover the plane.

If purists insist on paper, the one could deposit a thin foil veneer on the leading edges or deposit a trace-work of metal to create a reflector of radar waves (extra credit for adding an RFID chip to the mix).

Re:flip?

[calebt3]

The summary says the mini model was able to withstand 300 degrees C. And what's wrong with flipping? Paper airplanes that I make usually orient themselves that way, and they do quite well.

De-Orbit?

[twifosp]

Since I can't read japanese and therefore can't RTFA, I have a few questions.

The ISS Orbits the Earth at around 7.400k/s at an altitude of 365k. You can't just throw something out of the ISS and hit the Earth's atmosphere for Re-entry. If you "throw" it out of the ISS, it'll orbit, just like the ISS. In order to intersect with the Earth's atmosphere for areo-braking, you are going to need to lower he perigee of your orbit to at least 50-60k. You'll need a delta V of about 100 m/sec to do this.

What gives? Have they built an oragami retrograde rocket as well?

Re:flip?

[aadvancedGIR]

But your paper airplaines don't encounter strong temperature gradients or supersonic shock waves. In such conditions, even having the sun illuminate one side of the plane and not the other one could significantly alter the trajectory of the plane, and I believe is what makes the experiment interesting: will the real course match the planned one?

Re:why not metal foil?

[Speare]

People immediately wonder "why" they would do something like this. As far as has been reported, there won't even be an attempt to track the actual landing, and as we could expect, it would even be difficult to pinpoint which continent (if any) would receive the landing.

The point isn't what happens to the plane in ACTUAL freefall, the point is to do the materials and aerodynamics studies on the ground. Why not use foil? Because they have already tested foil in space and know quite a bit about it. Whether foil would work or not is not what this particular group wants to study. They haven't tested this kind of treated paper. Maybe there are some surprising benefits in heat-treated papers that could change the way we do satellites.

Of course, the final "experiment" is more like playing golf on the moon, if they even bother to do it at all. It's just a part of joie de vivre, which I think is sorely lacking in western society today. Stop griping needlessly. They won't spend a billion dollars to take a piece of scrap paper to space and chuck it into the big blue swirly spherical rubbish heap. However, thanks to this outlandish conversation-starter concept, they might be allowed to spend a significantly smaller budget on traditional material and aerodynamic science.

Some maths

[ringman8567]

400km up 27700 km/h the energy loss required is about 117kJ potential and 888kJ kinetic to land. say 1MJ. This is slightly reduceded as to get to an eacth grazing orbit the plane must be thrown backwards fom the space station eith a relative velocity of about 700km/h.

If we assume a surface area of 1000 sq cm, not unreasonable for a length of 30-40 cm, then and a re-entry time of 1000 seconds the energy must be lost at about 1 watt/sq cm, which seems possible.

The launch from the space station would appear to require rocket assistance.

If flying slow enough, why should it burn?

[ballestra]

We always think of re-entry of a spacecraft as this fiery process, but would it be possible for a paper airplane to approach the atmosphere slowly and enter it gently without any high temperatures? Perhaps someone can explain how this is impossible.

Paper planes for planetary exploration

[ErkDemon]

As far as has been reported, there won't even be an attempt to track the actual landing ...

New Scientist:

Suzuki says he would like to develop an ultra small tracking device to attach to the plane.

If you can track it, you can learn stuff about the reentry characteristics of ultra-light probes.

Now, think about the consequences of that for a moment. Most existing reentry vehicles are reentry vihicles designed to return personnel and equipment and data to ground level, but when you explore other planets the data flow goes the other way. There's also a lot of data that doesn't have to be collected from the ground. So, instead of an orbiter chucking two or three big chunky armored landers which attempt to survive crashing into the surface, and then trying to get a rover to crawl out of the lander and chug for miles to get somewhere interesting (without falling down a hole), why not release a cloud of ultralites and have them beam back picture info and data as they they drift earthwards? If you could insert an ultralite robotic aircraft into the atmosphere (of the type they currently use for weather sensing), it wouldn't have to land, and some of these designs might be able to stay aloft for years. Couple that with a microsatellite relay network and you potentially have a good system.

Alternatively you could go down the balloon path ... instead of a conventional balloon carrying a heavy heavy metal box with electronics in ... instead, stick your CCD chips to the balloon, print additional circuitry and perhaps solar cells directly onto the surface, perhaps use the upper and lower surfaces as charge carriers to avoid batteries, or have the lower surface metallised and the upper transparent, and use it as a solar collector.

With a whole bunch of these balloons drifting about in the upper atmosphere, you have an ad-hoc signal relay system. Hell, give em internet protocols. You won't be able to steer them, and you'd always be losing contact with a few, but a mission could carry along hundreds of them. The transponders would only have to be comparatively short-range, maybe you could even beam power from the orbiter. If you want random mapping plus a study of the atmosphere, bung 'em into a low orbit and wait for them to decay.

Perhaps a future Venus mission might well involve an orbiter repeatedly chucking a series of fifty cheap, disposable, "smart" transponder-equipped paper planes into the Venusian atmosphere and relaying that data back to Earth.

The first step is developing and testing materials. The second is using a tracking system to see how well they cope with reentry. The third is embedding smarter electronics.