A "Black Box" For Space Debris?

jonerik writes: "Space.com has this piece on engineers at El Segundo's Aerospace Corporation, who are trying to create a black box - similar to those used in civilian, commercial, and military aircraft - for satellites and other pieces of equipment bound for space, with the aim of trying to figure out why certain pieces of space debris survive reentry largely intact while others burn up in the atmosphere. The box - about the size and shape of a paperback book - would sit dormant perhaps for years and reactivate when a thermal switch senses the temperature rising, signalling reentry. 'Loaded with ultra-small sensors, including accelerometers and a Global Positioning System navigation chip, the box would record the stresses and strains on the hardware during its fall from space.'"

Why wait years

[dolphin558]

Just attach microjets to the black box and propel it toward the Earth's atmosphere. that way you won't have to wait for gravity to do its work.

Re:Why wait years

[Fantanicity]

You don't even need to do the experiment :-

If you want to have something survive reentry then make it out of the same stuff the black box is made of.

If you want something to burn up on reentry then make it out of not (the same stuff the black box is made of.)

In a word -- Spin

[Anonymous Coward]

Call it spin, tumble, or chaos, an object survives if it is able to spin. This distributes what part of the object heats, and how much damage is done.

Plus objects that spin tend to generate lift, which means drag, which means they slow down quickly after the initial entry.

Homework: go find a 1" x 2" x 30" piece of wood. Grasp it on one end. Out of doors, throw the wood in a level plane, attempting to induce much spin in it (like a boomerang). Make the plane level, and inclined slightly up.

When you let go, that piece of wood will start rolling and spinning, and will generate lift. It'll generate an audible hum, and toward the end of your throw, it'll stop moving forward, but the spinning and rolling will continue. The piece of wood will fall gently down to earth.

We used to play a game of catch with a piece of wood like this in my neighborhood as kids. Some yardsticks work, but they have to be heavy enough, and need to approach being square, but to not actually be square in cross section. (So thin and winglike is bad.)

Insightful? Not by a long shot!

[JUSTONEMORELATTE]

I can picture a boardroom at NASA

Hmmmmm.... We could build on 30+ years of research from the respective space agencies of France, the (then) Soviet Union, the United States and maybe a few others, then try to collect first-hand data via a transmitting device placed in some actual orbital craft which are performing uncontrolled re-entry. We could capture and track these data to see if we could correllate certain behaviours with re-entry breakup or lack thereof.

Or we could listen to a guy who throws sticks.

In a word -- Ouch

[Qwerpafw]

Homework: go find a 1" x 2" x 30" piece of wood. Grasp it on one end. Out of doors, throw the wood in a level plane, attempting to induce much spin in it (like a boomerang). up.

Interesting...

When you let go, that piece of wood will start rolling and spinning, and will generate lift. It'll generate an audible hum, and toward the end of your throw, it'll stop moving forward, but the spinning and rolling will continue. The piece of wood will fall gently down to earth.

So far, so good...

We used to play a game of catch with a piece of wood like this in my neighborhood as kids. Some yardsticks work, but they have to be heavy enough,

::thinks about throwing a heavy piece of wood::

::thinks about heavy piece of wood flying through the air::

::thinks about kid standing right in the trajectory of heavy piece of wood::

ouch!!!

what about heat?

[littlerubberfeet]

Size of a book? It better be the size of The Art of Computer Programming (Knuth). Most of the material would burn off. You would need to make it out of the silicon-based stuff the shuttle uses, and then reinforce it. In order to build it most efficently, it would need to be shaped like a water droplet (I forget the scientific name) as this is most aero-dynamic.

At any rate, due to material loss by heat, then loss due to impact, why not have it separate from the craft, then transmit the data, then burn up. This would be easy, just set a 24 hiur looped recording on a certain frequency, and leave it on. If it doesn't work, its not like a chunk of charred GPS components and silicon are gonna survive any more then a radio in space would.

Re:what about heat?

[hplasm]

I don't think it's meant to be aerodynamic, it's supposed to simulate space junk re-entering?

Re:what about heat?

[des09]

I am not an expert, but if I recall correctly, an erratic electromagnetic field is generated around an object re-entering the atmosphere, requiring a powerfull transmitter to generate a signal that would be usefull. Another challenge would be spin.