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.
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.
https://www.youtube.com/watch?v=o-mZ9pKvCmk - "Surprise!"
Sputnik wore out and spiraled back to Earth
On re-entry it burned up very soon
Hail and good-bye to that goose in the sky...
And in 12 more years a man walked on the Moon!
22, 27...either way it's incredible.
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.
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 having rocket motors that can be relit is a large technical challenge.
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
They were pretty visionary when it came to space exploration and even made the first serious study into potential manned lunar mission in 1938 using a ‘step rocket’. (https://www.bis-space.com/the-bis-lunar-spaceship/)
The control connections between cabin and hull would uncouple automatically on separation and the communication system would be switched from the four-dipole arrays arranged in blisters near the stem of the hull to arrays situated under the floor of the cabin. --->>>This moment can be described as the action of sildenafil.<<<--- Cabin attitude and rate of spin would be controlled by hydrogen peroxide jets.
[1] I assume it to be a salespitch by the URL, not having followed the link I can not be sure
The vehicle was the subject of his thesis with the following diagrams apparently being sourced from it, https://cdn.discordapp.com/attachments/836685279875956746/87... The design is a fairly striking, lifting body design being pursued in the early 60s! (Russian source, http://www.buran.ru/other/Buran_Gagarin.pdf )
This meant that the first human in orbit and on another heavenly body both worked on reusable space vehicles (Gagarin's vehicle and the Dyna-Soar by Neil Armstrong). That's a fairly incredible coincidence that begs the question; why? Why did two different agencies - walled off from each other at opposite ends of the world - converge on the same design?
Apparently, as with many things from that era, the answer is the Nazis. More specifically, the Silbervogel, a lifting-body, sub-orbital, liquid-fuel-rocket-powered vehicle designed in the 1930s by Irene Bredt and Eugene Sanger. This is the very first known design of its kind, and it seems to have shaped much of aerospace history. For e.g. regeneratively cooled nozzles trace their history back to this design, as the Silbervogel was designed to operate with one due to their early experiments/tests. They also did substantial work in the physical and physio-chemical properties of liquid-fueled rockets that stands as some of the earliest work on the subject.
Eugene Sanger has become well known in rocketry circles and has been credited for some of the analytical techniques used to estimate the performance of liquid-fueled rockets due to his book, Raketenjlugtechnik (Rocket Flight Technology) that he published in 1933 (along with additional literature later on). Because of this public material, the field remembers him as one of the origin points for these analytical techniques. But it turns out that might be wrong.
Thanks to the records about the silbervogel and subsequent reports - http://www.astronautix.com/data/saenger.pdf , I've found that Sanger was the engineer who designed the lifting body, but Irene was the mathematician and physicist who modeled their experiments and derived the calculations we use today. This fact is fairly exciting to a nerd like me. It's my first contribution to academia/the official record! :)
However, it's not that far off to say that Bredt & Sanger are both the progenitors of multiple sub-fields of modern aerospace research, especially re-usable spaceplanes.
More on the Buran: https://en.wikipedia.org/wiki/Buran_(spacecraft)
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.
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!
