For Questions That Don't Merit Their Own Thread

[munlander1]

Once the iss is decommissioned, what are  they going to do with it?

[kerbiloid]

What is English common word for (space)ships, rocket boosters, orbital station modules, satellites?
"Vessel"? (Is rocket a vessel?)
"Vehicle"? (is orbital station module a vehicle?)
(Except "craft", as in terms of KSP it strongly refers to *.craft files).
I mean, how can I name a subdirectory with all this stuff.

5 hours ago, munlander1 said:

Once the iss is decommissioned, what are  they going to do with it?

Any possibilities except deorbiting? (Except "all at once" vs "one by one").

Edited March 30, 2017 by kerbiloid

[p1t1o]

6 hours ago, munlander1 said:

Once the iss is decommissioned, what are  they going to do with it?

 

34 minutes ago, kerbiloid said:

Any possibilities except deorbiting? (Except "all at once" vs "one by one").

 

Well one thing is for certain, they sure as heck aren't going to turn it into an orbiting museum, or bring any part of it back to Earth intact.

[Kryten]

7 hours ago, munlander1 said:

Once the iss is decommissioned, what are  they going to do with it?

The plan for is to deorbit it into the south Pacific using a pair of Progress' or one of the new Russian TGK PGcargo vehicles. Some bits will probably come down intact, but you'll have a hard time finding and recovering them.

[StrandedonEarth]

11 hours ago, Kryten said:

The plan for is to deorbit it into the south Pacific using a pair of Progress' or one of the new Russian TGK PGcargo vehicles. Some bits will probably come down intact, but you'll have a hard time finding and recovering them.

I understand all the reasons why there is really no other option but splashing it, but I still can't help but think it's a waste of all that mass-on-orbit (a precious resource, IMO)

[munlander1]

1 hour ago, StrandedonEarth said:

I understand all the reasons why there is really no other option but splashing it, but I still can't help but think it's a waste of all that mass-on-orbit (a precious resource, IMO)

Well, we have gotten a lot out of it. I think the only other option would be boosting it in to a grave yard orbit. That would do nothing though.

[shynung]

On 30/3/2017 at 2:21 PM, kerbiloid said:

What is English common word for (space)ships, rocket boosters, orbital station modules, satellites?
"Vessel"? (Is rocket a vessel?)
"Vehicle"? (is orbital station module a vehicle?)
(Except "craft", as in terms of KSP it strongly refers to *.craft files).
I mean, how can I name a subdirectory with all this stuff.

I think "craft" would make sense as a common word. We have such words as "watercraft", "aircraft", and "spacecraft".

Not a linguist, so please don't quote me on that.

[sevenperforce]

2 hours ago, shynung said:

I think "craft" would make sense as a common word. We have such words as "watercraft", "aircraft", and "spacecraft".

Not a linguist, so please don't quote me on that.

Not a linguist either, but I did stay at a Holiday Inn Express last night.

Did I date myself? I think I just dated myself.

Craft is the preferred term to encompass everything. "Vehicle" works for anything other than a space station (launch vehicle, landing vehicle, transfer vehicle, ascent vehicle, etc.). "Module" can refer to the individual segmented components of a craft, some of which may be independently operable (crew module, boost module, propulsion module, landing module, excursion module, service module, command module, hab module, docking module, etc.).

[Spaceception]

What would it sound like on a planet with a third of Earth's sea level pressure?

Edited April 3, 2017 by Spaceception

[sevenperforce]

9 minutes ago, Spaceception said:

What would it sound like on a planet with a third of Earth's sea level pressure?

Not a lot different.

Humans can handle low air pressures (to a point) without difficulty, as long as the partial pressure of oxygen remains the same. John Glenn's capsule flew a pure-oxygen mix at 5.5 psi, which is just barely more than a third of STP. I don't think there was any great change in what he could hear, or how his voice sounded.

There might be a change due to air density, though, since the chemical mixture is very different.

https://www.ncbi.nlm.nih.gov/pubmed/8128881

 

[Spaceception]

2 minutes ago, sevenperforce said:

Not a lot different.

Humans can handle low air pressures (to a point) without difficulty, as long as the partial pressure of oxygen remains the same. John Glenn's capsule flew a pure-oxygen mix at 5.5 psi, which is just barely more than a third of STP. I don't think there was any great change in what he could hear, or how his voice sounded.

There might be a change due to air density, though, since the chemical mixture is very different.

https://www.ncbi.nlm.nih.gov/pubmed/8128881

 

Thanks! So this would make sense?

“Woah,” said Morales, somewhere behind her. He sounded about the same, but there was a small echo, which she supposed was from the helmets.

[kerbiloid]

http://www.engineeringtoolbox.com/air-altitude-pressure-d_462.html

1/3 atm ~= top of Everest

Probably her ears were plugged up and she got it as echo.

[sevenperforce]

46 minutes ago, Spaceception said:

Thanks! So this would make sense?

“Woah,” said Morales, somewhere behind her. He sounded about the same, but there was a small echo, which she supposed was from the helmets.

I guess we'd need to know a little more about the setup. Are they talking in the Martian atmosphere? What sort of helmets are they using? Is there an electronic relay?

[Spaceception]

16 minutes ago, sevenperforce said:

I guess we'd need to know a little more about the setup. Are they talking in the Martian atmosphere? What sort of helmets are they using? Is there an electronic relay?

It's a habitable moon with around 1/3 the atmosphere of Earth.

Similar to the ones that NASA has in their new helmets, but smaller, with flexible, strong glass (They can't breathe the atmosphere, and it's a bit too thin).

Yeah, but it's on the arm, and silent.

[Green Baron]

Long term adaptations to low air pressure work until about 5500; max. 8000 meters for a few specially trained persons at a very high risk and for a very sort time (hours). Anyway the risk of edemas rises. An untrained flatlander can have respiratory problems hiking at 2000m altitude.

See high altitude sickness, long term adaptation to altitude of the human body. We're not made for that :-)

Edited April 3, 2017 by Green Baron

[Spaceception]

11 minutes ago, Green Baron said:

Long term adaptations to low air pressure work until about 5500; max. 8000 meters for a few specially trained persons at a very high risk and for a very sort time (hours). Anyway the risk of edemas rises. An untrained flatlander can have respiratory problems hiking at 2000m altitude.

See high altitude sickness, long term adaptation to altitude of the human body. We're not made for that :-)

I know that, I've hiked before, I just don't know how it would sound with a helmet on to communicate.

[sevenperforce]

9 minutes ago, Spaceception said:

It's a habitable moon with around 1/3 the atmosphere of Earth.

Similar to the ones that NASA has in their new helmets, but smaller, with flexible, strong glass (They can't breathe the atmosphere, and it's a bit too thin).

Yeah, but it's on the arm, and silent.

Oh, so they are speaking through their helmets, in normal Earth atmosphere, without electronic amplification?

In that case you have sound traveling at one speed which is then attenuated by the glass, phase-shifted (with compression losses) by air of a different density, then attenuated again by glass, then phase-shifted again. So it would be REALLY muffled and slightly distorted, but not a different pitch.

So yes, basically correct.

20 minutes ago, Green Baron said:

Long term adaptations to low air pressure work until about 5500; max. 8000 meters for a few specially trained persons at a very high risk and for a very sort time (hours). Anyway the risk of edemas rises. An untrained flatlander can have respiratory problems hiking at 2000m altitude.

See high altitude sickness, long term adaptation to altitude of the human body. We're not made for that :-)

Risk of edema is there, yes, but otherwise altitude sickness mostly has to do with lack of oxygen, not with the pressure itself. People can last for long periods of time at very low pressure as long as the partial pressure of oxygen is high enough.

[Green Baron]

When exposed rapidly to lower oxygen partial pressure (>5000m for a sporty young person) funny things happen. The sense of judgement is severely limited. You feel great, invincible, but a simple calculation like glide ratio / altitude can become a real task.

[sevenperforce]

If they were speaking through a mask rather than a helmet (e.g.,  something like a respirator) and their ears were open to the surrounding air, then they'd hear everyone's voices with a pitch phase-shifted really, really low. The ordinary vibrations in ordinary-density air would be frequency-multiplied when they hit lower-density air.

[DerekL1963]

7 hours ago, sevenperforce said:

If they were speaking through a mask rather than a helmet (e.g.,  something like a respirator) and their ears were open to the surrounding air, then they'd hear everyone's voices with a pitch phase-shifted really, really low. The ordinary vibrations in ordinary-density air would be frequency-multiplied when they hit lower-density air.

I found the opposite when wearing an EAB...  Everyone's voices seemed higher pitched than normal.

[sevenperforce]

8 minutes ago, DerekL1963 said:

I found the opposite when wearing an EAB...  Everyone's voices seemed higher pitched than normal.

Soundwave phase transitions from a high-density medium to a low-density medium cause the frequency to decrease. The reverse case causes the frequency to increase. That's why breathing helium makes your voice sound high-pitched; your vocal cords are vibrating in low-density helium, which increases in frequency when it hits the denser surrounding air.

Was this in a sub? Is the EAB pumped at a different mixture or pressure than the surrounding atmosphere?

[DerekL1963]

Just now, sevenperforce said:

Soundwave phase transitions from a high-density medium to a low-density medium cause the frequency to decrease.

The transition from mask-to-atmosphere involves two transitions (light (interior of mask)->heavy (material of mask) and then heavy (material of mask)->light (open atmosphere)), you're only accounting for one.  (Not that frequency changes at a phase transition AIUI.)
 

3 minutes ago, sevenperforce said:

Was this in a sub? Is the EAB pumped at a different mixture or pressure than the surrounding atmosphere?

The EAB's drew from the compressed air banks and served via a regulator at atmospheric pressure, the air banks were charged from the open atmosphere.  So, long version short - bog standard air at local pressure.  (The boat's interior pressure could vary, usually *up*, from sea level pressure.)

[sevenperforce]

7 minutes ago, DerekL1963 said:

The EAB's drew from the compressed air banks and served via a regulator at atmospheric pressure, the air banks were charged from the open atmosphere.  So, long version short - bog standard air at local pressure.  (The boat's interior pressure could vary, usually *up*, from sea level pressure.)

Okay, then there wouldn't be any change in pitch from pressure gradients.

8 minutes ago, DerekL1963 said:

The transition from mask-to-atmosphere involves two transitions (light (interior of mask)->heavy (material of mask) and then heavy (material of mask)->light (open atmosphere)), you're only accounting for one.  (Not that frequency changes at a phase transition AIUI.)

Multiple transitions won't change pitch if the start density is the same as the final density. Water and glass will refract light, but the light coming through a flat windowpane isn't visibly refracted because transitioning from the air to the glass is cancelled by the following transition from the glass to the air.

The reason voices sounded high-pitched is probably because of differential attenuation. High frequencies and low frequencies are attenuated differently; the sound-through-mask effect probably attenuated low frequencies more than higher frequencies, making the remaining voices sound tinny.

[Green Baron]

From paragliding and small aircraft i can tell that the sound does not change pitch in lower pressure. Though the paraglider's helmet itself, if full face, dampens the sound of the surroundings.

Aircraft headsets and microphones usually filter out the noise of the surrounding. The better ones at least :-)

 

Edited April 5, 2017 by Green Baron

[K^2]

On 4/4/2017 at 1:31 PM, sevenperforce said:

Soundwave phase transitions from a high-density medium to a low-density medium cause the frequency to decrease. The reverse case causes the frequency to increase. That's why breathing helium makes your voice sound high-pitched; your vocal cords are vibrating in low-density helium, which increases in frequency when it hits the denser surrounding air.

No, this is absolutely wrong. Once sound is produced, its frequency will stay the same. The wavelength will change, certainly, but frequency has to stay the same. If you received more oscillations than were produced, where did additional ones come from? The future? Unless you are dealing with relativistic red/blue shifts that actually have to do with time behaving in a funny way, frequencies never, ever change. Be it light or sound.

On the other hand, certain means of producing sound will change in the source frequency as the speed of sound changes. Resonant frequencies of your voice will shift in Helium. But you'll hear that shift even if you are in a room filled with nothing but helium. Sound produced by your voice is already higher pitched in helium, and whether it transitions to normal air or not makes no difference. Likewise, any wind instrument will change pitch in a different atmosphere. And by the way, @Green Baron, speed of sound, and consequently certain sounds, will change with altitude. It won't touch things like engine sound, though, and won't be noticeable enough with voice, so it's easy to miss. Indeed, to get a sufficient shift, you need to climb to the point where you need an oxygen mask.