Any ideas of what would happen if you tossed a paper airplane out of a space shuttle as it began to reenter the atmosphere? My assumption is that it would burn up, but I was just watching the news and apparently a research group at some university (maybe Tokyo University) was actually testing it in a wind tunnel. So it must be an interesting question.

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As above, so below

1/ Would its lack of mass and weight mean that it would loose velocity very quickly on contacting the Earths atmosphere and just slow down to a gentle descent.
2/ Or would it just incinerate shortly after entering any significant density of atmosphear....
I am suggesting option 2. The shuttle de-orbits from 39000km/hr. Puts new meaning to the 'Running Hot' idea a?

That'd be a wonderfully cheap experiment, but a PR nightmare: spacewalking astronaut throws out a thousand handbills, all printed with "If you find this, contact NASA 1-800-548-8377"

Did they say how this wind tunnel would get air at ~30 Pa moving at Mach 29 ???

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"Those who cannot remember the past are condemned to repeat it" - George Santayana

Here's an old (short) discussion about a feather.

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Numbers are not case sensitive. (me)

Extensive discussion about whether a party balloon would survive reentry:

Balloon in orbit

A balloon has a greater surface area to mass ratio than a paper airplane, which makes me think it has a greater chance.

However it probably depends on the size and design of paper airplane, type of paper, etc.

If constructed of very thin paper for the lightest possible weight and greatest ratio of surface area to mass, it's conceivable it might survive.

E.g, the shuttle orbiter has a wing loading of about 100 lb per square foot. This gives an idea of how much mass (hence at orbital velocity, kinetic energy) is supported per unit area.

By contrast a paper airplane constructed from an 8.5 x 11" of thin paper weighs about 3 grams, and (depending on the design) might have wing loading of 0.01 to 0.027 pounds per square foot.

So at the low end, the wing loading is 1/10,000th the space shuttle.

Like a styrofoam cooler blown from a pickup truck, it would decelerate very rapidly at the slightest hint of atmospheric drag. It might never develop a hypersonic shock wave, hence might survive to reach earth.

might never? this is a piece of paper right? hard to imagine

Supposedly they found a couple of embroidered shoulder patches from the space shuttle Challenger astronaut uniforms that were in near perfect condition. So if a shoulder patch can survive reentry, a paper airplane might be able to as well.

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"Ignorance more frequently begets confidence than does knowledge" -- Charles Darwin

Challenger did not reach orbit. It blew up at about 48,000 feet, well shy of orbital velocity.

You are correct. I should have written "Columbia" instead of "Challenger".

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"Ignorance more frequently begets confidence than does knowledge" -- Charles Darwin

Even the videotape from one of the Columbia astronaut's camcorder survived and was playable, sort of. It had to have some repair work done to it.

I was under the impression that the Columbia shuttle had already taken the brunt of the re-entry at the time of the accident. No? Maybe I should look it up.

PS: This wiki article has a timeline, and it says the shuttle "entered a 10-minute period of peak heating" at around 8:51, and a transmission from the mission commander was recorded almost 9 minutes later.

Columbia broke up at about 203,000 ft (61 km) altitude at a speed of Mach 18 (13,700 mph, 6.1 km/sec).

Small objects like shoulder patches, papers, etc were immediately disgorged into an intense thermal environment, however some survived to reach the ground.

This was a much MORE intense situation than similar lightweight objects reentering from orbit. In that case they'd more slowly decelerate as atmospheric friction gradually increased.

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Everyone is entitled to his own opinion, but not his own facts.

...not to mention orientation...

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Everyone is entitled to his own opinion, but not his own facts.

The small "grain of sand sand" meteoroids illustrate an object:

(1) With a low ratio of surface area to mass
(2) On a steep reentry angle (30 degrees typical)
(3) At very high velocity (11 to 71 km/sec)

...will burn up

None of these apply to a paper airplane or a balloon reentering from earth orbit.

As opposed to a tiny meteoroid, a paper airplane:

(a) Has a high ratio of surface area to mass
(b) Is on a shallow reentry angle (1 degree)
(c) Is going much slower on average (7.8 km/sec)

For the airplane, the faint air drag at entry interface would cause aerobraking and rapid deceleration due to the large surface area, low mass and kinetic energy.

Compare a tiny "grain of sand" meteroid to a paper airplane:

Consider a reentering spherical meteoroid that is 1 cubic millimeter, specific gravity of 3 g/cm^3 (average), moving at 15 km/sec on a 30 degree entry angle (also average).

The cross-sectional area is 1.2 mm^2, and the mass is .003 grams. The ratio of cross-sectional area to mass is 4 square cm per gram, or 0.5 lb per square foot.

Kinetic energy is given by KE = 1/2 * m * v^2, so the sand grain's kinetic energy is 33,750 Joules.

Compare this to a paper airplane, mass 3 grams, wing area 500 square cm, reentering from orbital velocity of 7.8 km/sec.

The paper airplane's ratio of wing area to mass (wing loading) is 0.012 pounds per square foot, or 40 times lower than the "grain of sand" meteoroid.

The paper airplane's kinetic energy is 91,260 Joules, 3x the tiny meteor, but dispersed over 41,000 times the surface area.

The paper airplane must only dissipate 182 Joules per square cm, vs the meteroid's 2.75 MILLION Joules per square cm. That's why the tiny meteroid burns up.

I don't know for sure a paper airplane would survive, but it seems conceivable once you think about the physics involved.

My gosh, you mean that cliche has a basis in reality?
(The cliche of the hero finding a camera in the ruins of a disaster, and the hero plays it and finds out...)

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"If you think the LHC will create black holes, you might as well believe Hobbits are at the bottom of your garden."- Dr. Mike Inglis
Rovers forever! - ToSeek
"Carl Sagan sent a message to ET,
Neil Armstrong walked in the Sea of Tranquility
Steve Squyers built Spirit and Opportunity
Dan Haylen upchucked in zero gravity." -Brent Simon, The Space Camp Song

Make the "paper" airplane out of aluminum (aluminium if you're English) foil and track it with radar!

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Any day you wake up on "the right side of the dirt" is a good day.

T. Anderson

Wouldn't that just be space junk?

No, space junk is RCH's books.

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"If you think the LHC will create black holes, you might as well believe Hobbits are at the bottom of your garden."- Dr. Mike Inglis
Rovers forever! - ToSeek
"Carl Sagan sent a message to ET,
Neil Armstrong walked in the Sea of Tranquility
Steve Squyers built Spirit and Opportunity
Dan Haylen upchucked in zero gravity." -Brent Simon, The Space Camp Song