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Spaceflight Before 1951

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Re: Spaceflight Before 1951

#21

Post by OJFord »

dmd wrote: post #10
crubier wrote: post #7

Earlier quoted context omitted.

The delta-v from Earth Surface to Low Earth Orbit (beginning of space exploration) is 9km/s. The delta-v from Earth Surface to Moon is 15km/s. So basically once you learned to go to space, going to the Moon is "only" 60% harder, even thought the moon is 1000x further away.

The delta-v from Earth Surface to the bottom of the ocean is 0, so by your logic, going there is trivial.

Well when did you ever hear of a space agency bothering?

Jokes aside, I hadn't heard the term before and from what I could guess/infer didn't see how it could be a measure between two places: https://en.wikipedia.org/wiki/Delta-v

Re: Spaceflight Before 1951

#22

Post by gumby »

> Beginning life as a weapon, the V-2 was pressed into peaceful service after the war at the United States' White Sands Missile Range as well as the Soviet Union's Kapustin Yar.

This is a rather generous explanation. They began as weapons and their use was explored by the militaries of the victorious powers. Those research efforts were primarily to gain the knowledge of how to continue development of rocket weapons.

In the case of the US: NACA worked on air flight only; civilian space research only began with the formation of NASA in 1958.

Re: Spaceflight Before 1951

#23

Post by beerandt »

7373737373 wrote: post #4
david_draco wrote: post #3

Earlier quoted context omitted.

Does it really count if it is vaporized before leaving the atmosphere?

These calculations suggest that it indeed probably vaporized within a few meters due to the insane amount of heat: https://physics.stackexchange.com/questions/488151/could-the...

That meteor equation isn't the right one to use. It's based on assumptions that don't apply here. It has to be re-derived, at a minimum, if it can even be repurposed.

Any dt equation like that should have some value of X_final-X_initial for any constants that change.

For rho, he plugs in rho_initial for rho_final. And rho_initial in space is zero, so it likely got dropped from the equation when it was derived.

That said, if it even survived the initial xray ablation, yeah, it probably burnt up before reaching space, or at least slowed down enough that it came back down.

Re: Spaceflight Before 1951

#24

Post by mhh__ »

ustolemyname wrote: post #11
crubier wrote: post #7

Earlier quoted context omitted.

The delta-v from Earth Surface to Low Earth Orbit (beginning of space exploration) is 9km/s. The delta-v from Earth Surface to Moon is 15km/s. So basically once you learned to go to space, going to the Moon is "only" 60% harder, even thought the moon is 1000x further away.

I'm going to nit this for several reasons: 1. Walking on the moon implied a return trip which requires an extra ~3km/s. 2. Under the rocket equation the fuel requirements for more delta v grows superlinearly, which then awkwardly makes your rocket bigger, which requires more fuel... 3. 22 years prior a metal can went to space. The scale of a manned moon mission in comparison is absolutely nuts, even basic things like…

Addendum to point 3. It's not just a metal can, it's a metal can with some people in it. You have to keep them alive and useful for roughly a week, not just fling them at the moon.

Re: Spaceflight Before 1951

#25

Post by Xophmeister »

nautilius wrote: post #18
Xophmeister wrote: post #5

I realise this is a trite observation, but it never ceases to amaze me that it took just 22 years from the beginning of space exploration to walking on the moon.

27 years; that's what the whole linked article on wikipedia is about.

> Exploration of space began in earnest in 1947

22, 27...either way it's incredible.

Re: Spaceflight Before 1951

#26

Post by JKCalhoun »

areoform wrote: post #6

A few weeks ago a Russian-speaking friend in the aerospace industry (hey Dennis!) surprised me with photos of Yuri Gagarin (and other cosmonauts from Air Force Group 1) engaging with a re-usable lifting body aircraft, https://cdn.discordapp.com/attachments/836685279875956746/87... The vehicle was the subject of his thesis with the following diagrams apparently being sourced from it, https://cdn.discordapp.com/attachm…

I would just take issue with your use of "lifting body". The photo you linked to (and DynaSoar and the U.S. Space Shuttle for that matter) are closer to simple winged spacecraft and not what I would call lifting bodies.

Re: Spaceflight Before 1951

#27

Post by jefftk »

areoform wrote: post #6

A few weeks ago a Russian-speaking friend in the aerospace industry (hey Dennis!) surprised me with photos of Yuri Gagarin (and other cosmonauts from Air Force Group 1) engaging with a re-usable lifting body aircraft, https://cdn.discordapp.com/attachments/836685279875956746/87... The vehicle was the subject of his thesis with the following diagrams apparently being sourced from it, https://cdn.discordapp.com/attachm…

Re-usable spaceplanes were a technological dead end. They're much more expensive than even single-use rockets, let alone reusable rockets.

More on the Buran: https://en.wikipedia.org/wiki/Buran_(spacecraft)

Re: Spaceflight Before 1951

#28

Post by areoform »

JKCalhoun wrote: post #26
areoform wrote: post #6

A few weeks ago a Russian-speaking friend in the aerospace industry (hey Dennis!) surprised me with photos of Yuri Gagarin (and other cosmonauts from Air Force Group 1) engaging with a re-usable lifting body aircraft, https://cdn.discordapp.com/attachments/836685279875956746/87... The vehicle was the subject of his thesis with the following diagrams apparently being sourced from it, https://cdn.discordapp.com/attachm…

I would just take issue with your use of "lifting body". The photo you linked to (and DynaSoar and the U.S. Space Shuttle for that matter) are closer to simple winged spacecraft and not what I would call lifting bodies.

This was one of Yuri's original designs, https://cdn.discordapp.com/attachments/836685279875956746/87...

As you can see, it is much closer to the lifting body concept than the other craft. I suspect they converged on the Shuttle-like design because of cost and manufacturing constraints. But this unsupported speculation.

Also his designs incorporated grid fins! In the 1960s!

Re: Spaceflight Before 1951

#29

Post by areoform »

jefftk wrote: post #27
areoform wrote: post #6

A few weeks ago a Russian-speaking friend in the aerospace industry (hey Dennis!) surprised me with photos of Yuri Gagarin (and other cosmonauts from Air Force Group 1) engaging with a re-usable lifting body aircraft, https://cdn.discordapp.com/attachments/836685279875956746/87... The vehicle was the subject of his thesis with the following diagrams apparently being sourced from it, https://cdn.discordapp.com/attachm…

Re-usable spaceplanes were a technological dead end. They're much more expensive than even single-use rockets, let alone reusable rockets. More on the Buran: https://en.wikipedia.org/wiki/Buran_(spacecraft)

From a certain perspective, the Starship is a more evolved version of certain STS-Apollo variants - https://www.wired.com/2012/04/the-lut-the-shuttle-and-the-sa..., one proposed North American X15B design http://www.astronautix.com/x/x-15b.html and a few dynasoar configurations.

Spaceplanes haven't gone away. They've just been evolved. The Shuttle, for all its mistakes, got a lot of things right and brought incredible capabilities to the table that are well worth re-exploring and re-imagining.

Re: Spaceflight Before 1951

#30

Post by [deleted] »

mhh__ wrote: post #24
ustolemyname wrote: post #11

Earlier quoted context omitted.

I'm going to nit this for several reasons: 1. Walking on the moon implied a return trip which requires an extra ~3km/s. 2. Under the rocket equation the fuel requirements for more delta v grows superlinearly, which then awkwardly makes your rocket bigger, which requires more fuel... 3. 22 years prior a metal can went to space. The scale of a manned moon mission in comparison is absolutely nuts, even basic things like…

Addendum to point 3. It's not just a metal can, it's a metal can with some people in it. You have to keep them alive and useful for roughly a week, not just fling them at the moon.

[deleted]
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