Author Topic: FAILURE: Soyuz MS-10 - October 11, 2018 - Baikonur (DISCUSSION)  (Read 83650 times)

Online Svetoslav

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Okay, I correct myself. Choosing a random number just for convenience is pseudoscientific, of course. But according to Johnatan's latest research paper, the boundary of space is at least closer to 80km than to 100km.

Offline eeergo

It's a real space mission, as recent research papers confirm that space begins at 80km.

It's high time to consider the 100km boundary as arbitrary and pseudoscientific.

Since it is a gradual transition, setting it exactly at 80km is just as arbitrary and pseudoscientific. If a real measurement is used, are we to believe it fell exactly at 80km instead of 79.4km?  ::)

There's a nice paper by this very forum's Jonathan McDowell on the scientific reasons behind the proposed 80 km boundary. Of course there isn't a wall at 80-and-not-a-single-meter-less km so there's always gonna be some sigma in the definition.
-DaviD-

Offline Lars-J

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It's a real space mission, as recent research papers confirm that space begins at 80km.

It's high time to consider the 100km boundary as arbitrary and pseudoscientific.

Since it is a gradual transition, setting it exactly at 80km is just as arbitrary and pseudoscientific. If a real measurement is used, are we to believe it fell exactly at 80km instead of 79.4km?  ::)

There's a nice paper by this very forum's Jonathan McDowell on the scientific reasons behind the proposed 80 km boundary. Of course there isn't a wall at 80-and-not-a-single-meter-less km so there's always gonna be some sigma in the definition.

Yes I am aware of this paper, but that does not reduce the arbitrariness of setting it exactly at 80km.

Offline eeergo

Yes I am aware of this paper, but that does not reduce the arbitrariness of setting it exactly at 80km.

Any boundary, by definition, is gonna have that problem. Where's the boundary of the sea? How long is a coastline?

The conservative uncertainty interval given in that paper is ±10 km, surely it can be brought down a bit with more in-depth studies.
-DaviD-

Offline whitelancer64

Excellent analogy with the coastline. All coastline measurements are approximate, and they have to be, because the precise length changes constantly. Sediment loss / gain, tides, etc.

The atmosphere is similar, it is constantly in flux. In many respects, the higher the altitude, the more it can change. Decay rates of LEO satellites can vary quite dramatically depending on solar and geomagnetic activity.

So there will always be a "+ -" uncertainty for any definition of the altitude at which space begins.

Frankly, I'm fine with keeping 100 km for the purpose of aeronautical / spaceflight records. It's a nice, round number.
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Offline Phillip Clark

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I know that this is taking the conversation even more off-topic, but if 80 km were to be accepted as the new definition of "space", I wonder whether any non-Americans would then become an "astronaut".   And how many Americans would be added to the "astronaut list".
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Offline Olaf

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I know that this is taking the conversation even more off-topic, but if 80 km were to be accepted as the new definition of "space", I wonder whether any non-Americans would then become an "astronaut".   And how many Americans would be added to the "astronaut list".
At the moment this could only be pilots from the X-15 program.

Offline Moskit

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Maybe Nick Hague could be called "90.3% astronaut", and Felix Baumgartner a "38% astronaut"? ;-)
<duck&run>

Online Svetoslav

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Maybe Nick Hague could be called "90.3% astronaut", and Felix Baumgartner a "38% astronaut"? ;-)
<duck&run>

Then how percent astronaut is Mike Hughes? :)

Offline RonM

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I know that this is taking the conversation even more off-topic, but if 80 km were to be accepted as the new definition of "space", I wonder whether any non-Americans would then become an "astronaut".   And how many Americans would be added to the "astronaut list".

80 km is the American standard. No Americans would be added, they are already considered astronauts in the US.

Offline MattBaker

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Maybe Nick Hague could be called "90.3% astronaut", and Felix Baumgartner a "38% astronaut"? ;-)
<duck&run>

I guess we should change astronaut recruitment then since all those kids in Ecuador, Peru, Tibet or Bhutan are much more astronauts than those military pilots we've been getting. I mean, Annapolis is sea-level, how is that the foundation for an astronaut? Jorge, 12, lived all his life as a 3% astronaut in Ecuador, got one hell of a headstart

Online Steven Pietrobon

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80 km is the American standard. No Americans would be added, they are already considered astronauts in the US.

Technically, it is 50 statute miles or 80.4672 km. The US Standard Atmosphere has two regions, below and above 86 km. The lower atmosphere is explicitly stated with relatively simple equations for molecular temperature T_M (K) and pressure P (Pa). The upper atmosphere is much more complicated, requiring numerical integration to determine the number densities n_i (m^{-3}) of the major gas constituents (N2, O, O2, Ar, He, and H). When you enter the atmosphere where atomic oxygen is present, then I think that's a good definition of where "space" begins.

http://www.sworld.com.au/steven/space/atmosphere/
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Offline RonM

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50 miles or 80 km is close enough for two significant digits. We're not talking about atmospheric science, just when the bureaucrats feel comfortable handing out astronaut wings.

Online Steven Pietrobon

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50 miles or 80 km is close enough for two significant digits. We're not talking about atmospheric science, just when the bureaucrats feel comfortable handing out astronaut wings.

What if they fly 80.2 km? That is below 50 statute miles and therefore does not qualify for astronaut wings in the US.
« Last Edit: 12/14/2018 07:30 am by Steven Pietrobon »
Akin's Laws of Spacecraft Design #1:  Engineering is done with numbers.  Analysis without numbers is only an opinion.

Online Stan Black

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So you can only count swimming in the sea as an action below sea-level?

Offline RonM

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50 miles or 80 km is close enough for two significant digits. We're not talking about atmospheric science, just when the bureaucrats feel comfortable handing out astronaut wings.

What if they fly 80.2 km? That is below 50 statute miles and therefore does not qualify for astronaut wings in the US.

Jeez, what is wrong with you people? I was responding to someone who rounded off the number in an internet forum post. Yes, the number for handing out a reward in the USA is 50 statute miles. Not one inch less. Does that make you happy? Go design a rocket or something.

Offline jacqmans

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Rare (Roscosmos) photo of recovered orbital module of aborted Soyuz MS-10 spacecraft.
Jacques :-)

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