Society for Popular Astronomy

Skydiving for Nasa ..
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Author:  brian livesey [ Thu Oct 11, 2012 9:47 am ]
Post subject:  Skydiving for Nasa ..

Well, not quite, but Nasa will be interested to know how Austrian skydiver, Felix Baumgartner, makes out on his planned 25 mile drop from the upper atmosphere. Nasa's interest concerns the possiblity of having individual astronauts safely dropping back from space in special suits or pods in emergency situations.
Baumgartner might have a smoother trip on an airbed. He could lie back and read a magazine or listen to Johnny Cash on the way down. He'd better set his alarm clock too for the 'chute release :lol: .

Author:  David Frydman [ Thu Oct 11, 2012 10:22 am ]
Post subject:  Re: Skydiving for Nasa ..

Hi Brian,
I understand there are escape capsules on some aircraft possibly 747s for top politicians to use, although I am not sure how well they work.
Some aircraft, possibly the Mach 2 plus Hustler I think had the whole cockpit as an escape pod.
I think maybe the Miles supersonic jet we stupidly gave to the Americans also had an escape pod, which was the cockpit.

But starting off at say 17.000 mph should be quite a ride.

The fellow trying to break the sound barrier just falling.
The previous thread about the speed of sound on Mars is relevant here.

I think over 600 mph has been achieved already by a skydiver long ago jumping out of a balloon.
I am not sure if he was quite supersonic.

When I was in the air cadets I was told not to bother too much with parachute training as I would probably fall out of the parachute pack.

Regards, David

Author:  brian livesey [ Mon Oct 15, 2012 9:43 am ]
Post subject:  Re: Skydiving for Nasa ..

It was a relief to know that the Austrian stratonaut made a successful descent and landing. His downward acceleration exceeded expectations at just over 833 MPH!

Author:  David Frydman [ Mon Oct 15, 2012 1:32 pm ]
Post subject:  Re: Skydiving for Nasa ..

Someone will point out it is speed not acceleration.

I think somehow he reduced the resistance compared to long ago when somebody got up to 600 mph plus.
It could be the suit is more streamlined and has less drag.
Or the adopted position different.
In a normal jump terminal velocity is 120mph for the human body, but in a streamlined dive they get up to 190mph.
There are several cases where instructors have chased students who failed to open their parachutes, caught up with them and saved their lives.

Does it say what the Mach No. was for 833 mph? It varies with height and temperature.
At what height did he reach 833 mph?

Regards, David

Author:  brian livesey [ Mon Oct 15, 2012 3:19 pm ]
Post subject:  Re: Skydiving for Nasa ..

How fast would a stratonaut have to be travelling through the atmosphere to burn his breeches off ( wool not Polyester! :lol: )?

Author:  David Frydman [ Mon Oct 15, 2012 3:40 pm ]
Post subject:  Re: Skydiving for Nasa ..

Strangely enough my test to see what material a carpet was made of was to take a tuft out and try to light it.
Wool and different artificial fibres burn differently or sizzle, and by smelling the smoke a diagnosis is made.

Not sure I want to smell the burning or smouldering breeches though, but I probably could tell you what they were made of.

If he is coming from outer space I suppose the skipping stone method might work and Nomex?
Maybe make some toasted sandwiches on the way down.

Regards, David

Author:  brian livesey [ Tue Oct 16, 2012 9:29 am ]
Post subject:  Re: Skydiving for Nasa ..

Does anyone know the maximum attainable altitude a ballon is capable of reaching in Earth's atmosphere? Presumably, if Baumgartner had used an hydrogen-filled balloon instead of helium, he would have gone higher than he did.

Author:  David Frydman [ Tue Oct 16, 2012 9:48 am ]
Post subject:  Re: Skydiving for Nasa ..

I think it is near the limit with a payload.
At a guess 140,000 ft.
Not sure how much hydrogen would go.
Without a payload maybe quite a bit higher.
I think the density and temperature varies, so it might depend where, what season, what place etc.

the older record was held by his mentor. I knew long ago, maybe 1960.
The reason the speed was so high is that just a little increase in height brings big speed increases, because there is so little air very high up.
So I think 1,000 mph will be quite easy if you go a litttle higher.

I have seen suggestions of Mach 1.25 still somewhere around 100,000 ft was his 833 mph.
They say Mach 1 was 690 mph.
Normally at 36,000 ft and higher it is about 662 mph.

I think the diving Spitfire from 52,000 ft in the 1950s at around Mach 0.93? is incredible for a non jet.
I wouldn't like to try it.
A few airliners have just past Mach 1 in screaming dives I think a Boeing 727 and some others.
Also A Victor bomber exceeded Mach 1 over Hatfield I think.
at Mach 0.88 in a Trident the cockpit vibrated like crazy although the pilots did not seem to notice it.
To me it was obvious in the cockpit.
Yet in the passenger cabin it was smooth.
Very strange.

I used to regularly hear sonic booms in the 1950s and 1960s.
The RAF had to pay for lots of broken windows.
I also used to see aircraft at height at clearly Mach 2 with the contrail and tiny dot of an aircraft seemingly at Warp factor 5.

I am not sure how much of a bang this skydiver achieved. I doubt anyone heard it?

regards, David

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