First Photos of the Reentry of the ATV "Jules Verne"

White Yeti writes with news of the reentry breakup of the ESA's Automated Transfer Vehicle. All went as planned, and the ESA blog has preliminary photos. An international team of observers, in two aircraft south of Tahiti, saw a series of explosions and over a hundred small pieces of debris. Observations were mostly made using optical cameras and spectrographs. The two images on the ESA site are low-res samples, so we should get more spectacular images soon.

Question about atmospheric friction

[Viol8]

At what speed do you have to travel in the atmosphere before the cooling effect of air rushing past is overtaken by the friction effect and you start heating up again? I remember reading that concorde used to heat up on the outside but subsonic airliners don't. Does it have anything to do with the speed of sound?

Re:Question about atmospheric friction

[juletre]

The Concorde was a foot or two wider during flight. A pilot once put his hat between two cabinets/shelves/storage units (can't remember) during flight. When they landed and he wanted his hat back, it was so squeezed in between the shelves it was impossible. It had to be removed on the next flight.

According to Top Gear's Jeremy Clarkson, at least.

Concorde widens during flight

[juletre]

I'll reply to myself with a link [wordpress.com], after I did some googling. It contains a picture of the hat-episode. (search in page for "hat in the seam")

I'm curious...

[apodyopsis]

I had a hunt on the net - but did not find anything.

did *anybody* ever get hit by a falling satellite?

or radiation damage?

or property damage?

anybody know?

Re:Question about atmospheric friction

[Richard_at_work]

Wrong dimension - Concorde did expand, but lengthways (not to say it didnt expand widthways, it just didn't do it noticably).

The flight engineers cap story is real - during the last flight of each Concorde at their retirement, each flight engineer placed his cap in the space between their console and the rear compartment bulkhead. The caps can be seen to this day, stuck there.

Re:Question about atmospheric friction

[Anonymous Coward]

Another example is the SR71 "Blackbird". It was designed so that all parts would fit perfectly only when it was very hot during flight. And since it lacked a heat resistant fuel containment seal, it would leak fuel in the ground until it took off, flew for some time to heat up and then it had to be refueled on air.

Wow !

[o'reor]

The video of the re-entry [esa.int] is just beautiful !

Re:I'm curious...

[meringuoid]

Some parts of Skylab landed in inhabited parts of Australia; IIRC, an American newspaper had offered a prize for the first Skylab fragments handed in, and an enterprising citizen picked up some bits from the roof of his house and took them with him on the first flight over there.

Re:Why explode?

[mbone]

... there is now talk of developing an upgraded ATV which would include a re-entry module, and make ATV into a complete manned spaceflight system.

There is pretty serious talk - they put together a model they showed off in Berlin [bbc.co.uk].

They would be crazy not to pursue this.

Re:This shows a failure of imagination.

[hanshotfirst]

If we really want to become a spacefaring civilization, we have to stop thinking in terms of billion dollar garbage runs, and start thinking in terms of what can we do with what we have.

Of course, this is the same civilization that makes it cheaper to scrap a printer and buy a new one than replace the ink.

Re:Question about atmospheric friction

[mbone]

Sorry, I am going to call BS on this.

Friction is not a basic concept - it has to do with the behavior of large number of atoms. It is thus basically a thermodynamic concept - ordered motion gets converted into heat via turbulence.

So, there can be fluid friction, even fluid-fluid friction (a useful concept in meteorology) and when the fluids are supersonic, shock effects become important. There is no reason you can't call that friction too.

In modeling real systems, you can almost never estimate friction from first principles. In many real systems, friction is a "bucket" for a host of complicated small scale effects that get lumped into some large "frictional" drag or heating model, typically depending on some power of the fluid velocity, which is exactly how supersonic friction is handled (at least to first order). So, putting shock effects into the friction bucket is a useful concept, which means it is good physics.