Rocket Science 301: Radical Concepts in Propulsion; Man

[theberlindoctor]

Great video man. As a layman, I learned a lot.

[matthewakian2]

For all you scientific minded people (cause I don't have a clue), would it be possible to have a space station in low earth orbit (or maybe a bit higher), where a section of the space station could be lowered on a tether into the Earth's atmosphere, low enough that a high flying plane or similar could board, and then be pulled back up into Low Earth Orbit?

[currentliabilities]

@matthewakian2 In theory, yes. If you did not lower it deep into the atmosphere, because of overheating and drag. Realistically, no. It's not practical. The ISS orbits at an altitude of about 390km at a speed of 7.7km/s (the atmosphere ends at about 80km). If you're going to get something going that fast (Mach 28 at 75km altitude), then you're better off just boosting into orbit. The SR-71 max was Mach 3.3 at 24k.

[matthewakian2]

@currentliabilities Thanks. 

[matthewakian2]

The hypersonic craft discussed around the 20:00 point sounds a lot like the Skylon spaceplane the Brits are developing.

[AeonicMedia]

i deduce that at any point below geostationary orbit the cable will want to fall and beyond that point it will want to fly away from the earth......it is just a hunch but the weight of the cable closest to the earth will be much greater than the cable out of gravitys reach so as such my hunch is that the inner cables length will be the RMS (Root Means Square ) of the outside length of cable to make a balanced(ie Untensioned) cable

[aepceo1]

Yes, we've flown scramjets. Infact we have been for a while. They are all prototypes from NASA and whatnot though. Technically what they do is they take in supersonic air, the air compresses by shockwaves, compression gets so high that it heats the air, they inject fuel and it combusts. Theoretical maximum velocity is around mach 24 although the fastest anytime soon is around mach 12-14.

[surfsup927]

this guy is slow. he knows what he is talking about but he must be one of those aerospace engineers that took 30 years to get his degree

[sourmanofcoal]

@surfsup927 and what do you have? Instead of calling people dumb, clean your own asshole faggot.

[sourmanofcoal]

@surfsup927 he doesn't look 50

[Dudeness21]

if only magneto-ion (anti gravity) technology actually worked. Rather like communism; The theory is sound, in practice however it's too complicated to achieve economically.

[JJGMUSIC]

Also, imagine a composite material lighter than aluminum but could be magnetized the rest is secret.

[JJGMUSIC]

The string would collapse inward towards the earth because of centrifugal force below the stratosphere. Rocket propulsion is gay. If they found this awesome type of metal or composite they wouldn't use it for a retarded elevator. They would use it for those antigravity space ships that i worked on at area 51. The secret is any american can learn from nasa on not what to do. Obama is shutting them down cause they are a bunch of retards stuck in the past. KISS Keep it simple stupid.

[UnTiedMusicStudio]

@JJGMUSIC Go do a little research. The only thing keeping a space elevator from being built today is the tensile strength of the tether. They're about 3x away from being able to do it today (2011). Check the Spaceward Foundation, the Strong Tether challenge (not won yet), and the Beamed Power Challenge (which has already been won by Laser Motive). The physics is completely sound. We could build one on the moon today and use it to launch materials back to earth.

[hayden50]

thanks !!!

[goobtron]

There is no centrifugal force. It's called inertia.

[GenevaSuspension]

Reply 1 of 4

There are a few major flaws with the space elevator concept:

1. feeding a the cable from a geo stationary orbit won't work because the rope is in geostationary orbit with the satellite "cable dispenser", so the pull of gravity is exactly opposed by the angular momentum, and the cable won't "fall" to Earth. The cable won't be stiff enough to feed to a sufficiently lower orbit such that the pull of gravity is greater than the angular acceleration keeping it in orbit.

[Blazeus2]

Ohh sry that's what he says.. my mistake..

[lejink]

i have a question about the space elevator.

when its constructed, and a payload is climbing the line.. wont it slow the line's orbit? because the payload must be accelerating as its climbing, and gaining that acceleration from the line itself.

so it will be pulling on the line as it climbs so the middle will lag behind both ends..so if the space end accelerates to save its orbit it would slingshot the load forward causing another wave to correct. know what i mean? how would this be worked out?

[bellavitarox]

Thats what she said.

[BeingSomeoneHuman]

Ramjets are very proven and are still in operational use one of the most famous examples is the sr71 blackbird which channels its input around a standard engine to a ramjet after it reaches 700mph. Scramjets were first used by QU in Australia and later by nasa. Ramjets were first used by the Germans before WWII and have been in lots of cruse missiles.

[AlwaysHopeful87]

Another nice video. This subject may become very ripe if the H3 mining on the moon takes-off.

[ikanipo]

yea but there aren't alot of "smart" people in the world.

[midnighttutor]

rocketscientist say:  a lot not alot

[Dudeness21]

@midnighttutor I think you proved his point though...

[sourmanofcoal]

@Dudeness21 he doesn't look 60.

[GenevaSuspension]

There are more children in India with higher IQ's than the highest IQ values determined in US children, than there are children in the US. There are a lot of smart people in the world, but a lot of them lack direction and mentorship.

[evilferret132]

@GenevaSuspension very veryh true

[kryptoniterxn117]

this is wat ppl need to pay attention to, not what's in bt britney's legs or how lindsay is a lesbo.

[sparky577]

Yes Yes YES!

Britney's crotch gets more attention than a space shuttle mission these days!!! If we devoted as much time, money and popularity to developing space travel and solving problems like the lack of rail transport in the U.S. we'd be a hell of a lot better off.

[limpanbe]

can i quote that on my blog ?

[alfwiz]

Nice drawing at 23:35