Latest cold war weaponary?

To Russia with Shivers.

Laser Weapon Test

Will the US find this another good opportunity to test airborne lasers... or are the gases; subject to 1 year of space radiation, now sufficiently mutated to bring a virus to the earth....

@Pete

I think your irony-detector may be in need of an upgrade, mate!

(Or maybe yours was an ironic comment?)

It's not very fast is it?

I know a 15lb lump of something travelling at 100mph could easily kill someone, but 100mph doesn't seem very fast for something that fell from space.

Tracking

If anyone has the overwhelming desire to know exactly where this reservoir is (like me), have a butchers here:

http://www.n2yo.com/?s=31928

Pong

Oi! This is a tech site -- pong can only mean one thing.

(Nothing to do with smells.)

Disposal of space junk

> There were never any plans to engage the innocuous coolant assembly with a volley of missile-defence interceptors

Did the author mean "noxious" rather than "innocuous"?

And can anyone explain why this sort of space junk isn't propelled in the direction of The Sun (no, not the tabloid 'newspaper'!), just like we always used to throw stuff into the wide, wide, ocean, confident in the knowledge that it was So Big that no harm would result?

rocket belt

On the assumption we're going to keep chucking large lumps back down to earth, would it be practical to have a rocket pack, which could be 'joined' to such stuff, and used to make a more predictable impact area ?

I'd imagine over a year, a very low amount of thrust, maybe even from solar cell's would be sufficient ?

WOW!

A Fridge thrown from a space station!

Now that has to be way more fun than throwing a humble shopping trolly off the top floor of a block of flats.

Be glad its not that blocked portaloo

Ewww.

@Nick

> Even in orbit the gravitational force is still significant, it's just balanced by the centripetal force.

No.

In this particular case, the gravitational pull of the Earth *is* the centripetal force that acts on said orbiting object. Imagine that gravity suddenly failed... no centripetal force, so said object carries on in a straight line, i.e. at a tangent to the previous circular orbit.

What you mean is that the gravitational acceleration of the object for that particular orbit is equal to the value for centripetal acceleration (the rate of change of tangential velocity) that keeps the object's distance from the Earth constant: the radial rate of descent is zero.

@Mark - Not really

You are right that the terminal velocity of a skydiver is about 120mph, but that's because skydivers are particularly un-aerodynamic things.

My conjecture is that a large stinky space fridge would be quite a bit more aerodynamic than a man. For example, I went to NASA's online terminal velocity calculator here:

http://www.grc.nasa.gov/WWW/K-12/airplane/termv.html

And I entered a weight of 15lb (like the article suggests), a cross-sectional area of 0.25 sq ft (a guess) and a drag coefficient of 2.1 (what Wikipedia suggests as the Cd of a "smooth brick").

Falling from 60,000 feet, that gets up to a fairly decent 345mph.

You can have all sorts of fun lobbing large imaginary objects from space to the ground. I reckon a Toyota Prius (Cd 0.26, mass 2921lb, cross-sectional area about 25 sq ft) would hit the deck at a monster 1306mph, which is a fair bit better than it can manage down the M4.

So thanks for the science lesson, but I think we have to dig deeper. What is NASA not telling us?

Low energy transfers

Ok, Joe, you apparently don't have a job and want to calculate something. So don't forget to factor in http://en.wikipedia.org/wiki/Low_energy_transfers for your Rube Goldberg badge.

@AC (shoving the space junk to the Sun)

" I think the clue was in the word 'propelled' - I was hardly suggesting that an astronaut should give a gentle push to this chunk of space stuff, and expected it to whiz off sun-wards.

Perhaps someone knowledgeable (like a few of the subsequent posters?) could assess how much effort would be required to break it out of orbit and direct it towards the sun?"

Sure thing. According to the article, the tank is 1400 lbs (call it ~600 kg) and tudelft.nl lists impulsive shot (i.e. all the delta v is applied in a short time period) delta v for LEO to escape velocity as 3.2 km/sec. From kinetic energy = 1/2 mv^2, this gives us 300 * 3200 * 3200 or ~ 3 gigajoules (roughly 850 KWh) of energy. From there, if you were to kill off your orbital velocity around the Sun, then the Sun's gravity would take over and the tank would fall into the Sun. I didn't see any delta v listed (Solar impact is not a very popular space probe mission), but I can't see it as being worse than Earth's orbital velocity of ~30 km/sec which would require about 270 gigajoules (75000 KWh). In other words, I think you could safely characterize the energy requirements for solar impact as a "sh*t load"

Even if you used some really fancy orbital slingshot trajectory work to reduce the solar impact delta v to little more than Earth escape delta v, you would still have to bring up a rocket motor and reaction mass (at a price of ~ $10,000 a pound or more) to manage this. Executive summary- using the Sun as a trash disposal is extremely expensive.

This is why you dont drink with astronauts!

Hey mate could you chuck us a beer...

Here have a couple [CRASH!]

@Evil Graham - It's worse than that, Jim

NASA's calculator is only accurate for objects falling vertically, so if you lifted a Prius up to (say) 100,000 feet in a balloon and then dropped it, it would indeed reach a terminal velocity (the speed at which air resistance balances weight) of 1,300mph. But our pong-bomb will reach the upper atmosphere with an (almost) horizontal component of orbital speed - say 17,500mph.

My powers are too weak to calculate whether air resistance will have time (free fall to earth in a vacuum from 100,000 feet is about 80 seconds - reentry times are typically around a couple of minutes) to scrub off all this horizontal speed, but I observe that meteors (which admittedly reach the atmosphere with 2-3x greater speed) don't land vertically.

No brain'r

What goes up.... must come down.

@Chris - nice one

I hadn't thought of that (which is why I'm not in charge of any orbital pong-fridge equipment or anything).

But I still reckon it's safe to say these ex-fridge lumps are going to hit the deck at more than 100mph, even diagonally.

Sad

Yes, just like on Earth so it is in Heaven. You pitiful little meatsacks strewing you garbage all over the place.

I shall now double my efforts in the lobbying of the Galatic Council to keep you vermin in your own solar system. Yes, the cost of a Dyson Sphere is astronomical but it will be worth it, at the very least the place will be tidy.

Smell you later, smell you later forever.

Aerodynamic

"My conjecture is that a large stinky space fridge would be quite a bit more aerodynamic than a man. For example, I went to NASA's online terminal velocity calculator here:"

Actually the human body is suprisingly aerodynamic. One reason may be why the aquatic ape idea is true. Scuba divers (especially those spellunking) KNOW to a great degree how much harder it is to push yourself backwards through water because that way is not as aerodynamic as going head first.

Add to that jobbies float probably even better than the human body does and this frigde won't be 100% jobbie, and you have a shape that is much LESS aerodynamic than a skydiver and less dense along with it (though of greater volume, maybe). A terminal velocity of less than 120mph seems acceptable.

cosmic chiller screams to earth

Sweet mother of Zeus, I love this website!