Un- conventional ways to LEO

JoshNH4H · 2007-12-28 08:28:08

What about giving it some added velocity by something cannon like at ground level. Very jules verne, but still somewhat feasible. nothing huge, maybe a ton of TNT (is that a lot? I dont know) As it's not on the rocket, the rocket equation doesn't apply.

RedStreak · 2007-12-28 13:18:08

I might have one semi-worthwhile idea: blimps as launching platforms.

As I recall earlier in this discussion, the main problem with blimps and planes is they have a limit to how they can float. After hearing that I thought "Ok...so obviously not much good for manned craft, and designers might still worry over the hydrogen ala Hindenburg which continues to haunt diregible-nauts to this day."

What about rockets like, say, Pegasus? Here we have a rocket that already is lofted into space via airplane, is briefly dumped and fires into space while it's launch platform returns to Earth. An unmanned hydrogen blimp cruises/floats up to its maximum altitude and does the same thing. Assuming the blimp can reach an altitude above clouds and even jet streams would this altitude lift ease the pressure put on the rocket during its launch - I know that is a factor all rockets accomidate hence the nosecone shroud that's shed in space; lessening one burden always helps.

Before anyone criticizes outright, can I get some figures? How high can a jet get and then how high could a helium/hydrogen blimp do? For that matter, moving parts included, how does the complexity of a ramjet compare to a blimp?

Liquid hydrogen is annoying to contain, but gaseous at least no cryogenics required. If you're worried about maneuvering the blimp in a low oxygen/low atmosphere condition consider either small rockets or better still air-jet thrusters (no combustion at all).[/b]

JoshNH4H · 2007-12-28 15:12:26

I have pressure on air density above. about 1-2 km/s are lost to drag in a craft launching from earth. Launching from balloons to remove this is somewhat silly, as if you go too high, the balloons become too big to be economical

noosfractal · 2007-12-28 16:50:47

blimps as launching platforms.

JP Aerospace has probably taken this idea the furthest ...

http://en.wikipedia.org/wiki/JP_Aerospace

What about rockets like, say, Pegasus?

The problem is that mere altitude doesn't get you much. You need orbital velocity and lots of it. The main benefit of Pegasus' carrier aircraft is that they can avoid some launch scrubs due to bad weather. But balloons are even more sensitive to weather.

RedStreak · 2007-12-29 00:58:31

Well that kills off the balloon idea if all you can get is 2 or 3 km high. I was aware of velocity but curious on if the lack of atmosphere at higher altitudes could help any. :?

That pretty much leaves scramjets and space tethers now for ideas with current technology.

Terraformer · 2007-12-29 06:58:24

JP aerospace managed to get to 140,000 feet, if I recall correctly. That is 42 km high. If you can boost that to 50 km you're halfway into space.

JoshNH4H · 2007-12-29 11:28:05

but just b/c you're in space doesn't mean that you're in orbit. the redstone rocket went into space, but was only traveling at mach 10, while orbit is 25.

Terraformer · 2007-12-30 06:34:18

Ah, but for suborbital flights it saves a lot of fuel. And maybe if a pickup idea could work (the craft gets to the orbit as the station comes round and locks onto the station, giving it the nessercary speed to remain in orbit.)

JoshNH4H · 2007-12-30 09:14:50

but then the station needs to boost to regain the velocity it lost by speeding the rocket up. Balloons are only helpful in suborbit applications.

Terraformer · 2007-12-30 11:53:04

But... a not-for-profit group like Marsdrive can afford sub-orbital flights with blimps. And that means they can charge money. Which vastly increases their funding. Meaning they can start work on an orbital craft.

Another upshot: Access to microgravity for cheaper. Universities could afford to do more tests for the same budget (currently they have to fly on the Vomit Comet) The craft then wouldn't need rockets (it doesn't need to reach the Karman Line) and could just be a glider. Maybe even schools would be able to afford flights on it.

JoshNH4H · 2007-12-30 19:00:24

yes, it can. but only it. Face it- the applications of suborbit are 1/100 the applications of LEO (which, in turn, is 1/10 that of the moon, which is 1/10 that of mars)

Terraformer · 2007-12-31 07:47:51

And you plucked those figures from which thin air? Wikipedia?

JoshNH4H · 2007-12-31 10:00:39

And you plucked those figures from which thin air? Wikipedia?

Firstly, wikipedia is very reliable.

Secondly, no, those are my own guesses. However, I used them to illustrate that the only use for suborbit is quicker plane services. Let me straiten something out for you: If you were on a non-mooving pskyscraper 300 km tall, there would be about .95 g. Suborbit is just like the vomit comet. It has its applications, but very few of them.

Terraformer · 2007-12-31 11:21:32

Firstly, wikipedia is very reliable.

If you're looking for a bit of general knoledge, yes. If you're looking for actual info to use to rubbish someones idea, no. They don't get there physics right. I take it with a pinch of salt.

Secondly, no, those are my own guesses.

So I can't trust them. Face it, the only exra application of LEO to suborbit is sustained microgravity. The only extra applications of Mars than the Moon is a slight atmosphere and exta surface area, which until new rockets are developed are cancelled out by the increased distance.

but then the station needs to boost to regain the velocity it lost by speeding the rocket up.

And the fuel nessecery can be delivered by unmanned rocket, leading to increased safety for manned flight.

If you were on a non-mooving pskyscraper 300 km tall, there would be about .95 g.

Th ISS is 360 km up and at that height the gravity of the Earth is 0.88 of ground level.

JoshNH4H · 2007-12-31 11:46:58

Your "idea" is completely ridiculous. Balloons are unreliable, low powered, expensive, flammable, and completely pointless. You're trying (and failing) to solve the dilemma of the 21st century with technology from the 18th. Youve seen the balloon size for JP aerospace, it's simply not equipped for mass transport. yes, basically the prime advantage of LEO over suborbit is that you can stay there. But think of what comes with that, good space stations, power generation, communications satellites. A whole economy that cannot be done in suborbit. This idea is completely unfeasible and pointless.

As a final note, this is NewMARS, not NewSUBORBIT

Terraformer · 2007-12-31 12:40:11

Yeh, I can see that. I can also see none of you will ever get to Mars if you carry on insisting using such expensive and dangerous tech as they have nowadays or the stuff being concentrated on like space elevators. 'Oh no, the space elevator has fallen out the sky and completely wrecked a continent. We'll have to rebuild it. What, the Continent? No, the Space Elevator.'

Balloons have a better track record than rockets, are cheaper, and, for your information, NOT FLAMMABLE! They are lower powered, yes, but that's because they require less energy than rockets to get to a given height (I admit, there is a limit, but that's is where you USE A ROCKET). Just because they can't be used to get into orbit, doesn't mean the entire idea should be thrown out of the window. I have much better ideas than you. A space elevator begining 102-3 km up would not work.

You lot focus to much on Mars. I don't know why I bother going on this forum. Nothing ever gets done. We just talk, talk some more, then throw out a perfectly good idea. I'm glad you lot aren't in charge of NASA, it would be even more inefficient than it is at the moment. NASA don't read these forums so there is no use in talking about ideas that will never get acted upon.

JoshNH4H · 2007-12-31 13:50:00

Yeh, I can see that. I can also see none of you will ever get to Mars if you carry on insisting using such expensive and dangerous tech as they have nowadays or the stuff being concentrated on like space elevators. 'Oh no, the space elevator has fallen out the sky and completely wrecked a continent. We'll have to rebuild it. What, the Continent? No, the Space Elevator.'
Balloons have a better track record than rockets, are cheaper, and, for your information, NOT FLAMMABLE! They are lower powered, yes, but that's because they require less energy than rockets to get to a given height (I admit, there is a limit, but that's is where you USE A ROCKET). Just because they can't be used to get into orbit, doesn't mean the entire idea should be thrown out of the window. I have much better ideas than you. A space elevator begining 102-3 km up would not work.
You lot focus to much on Mars. I don't know why I bother going on this forum. Nothing ever gets done. We just talk, talk some more, then throw out a perfectly good idea. I'm glad you lot aren't in charge of NASA, it would be even more inefficient than it is at the moment. NASA don't read these forums so there is no use in talking about ideas that will never get acted upon.

A space elevator falling would burn up in the atmosphere.

If I were you, I wouldn't poo poo the shorter space evevator. A suborbital craft would be needed to go there, providing some use for suborbit (Although, scramjet, NTR, NIXRS, ETC would be MUCH more effficient) that is, or course, ignoring its multiple advantages.

Oh, I'm sorry, terraformer, actually, I WAS under the impression that you were supposed to talk at forums. Silly me. :shock: Since I'm a multibillionare ( I wish) I'll just send people to the moon and mars all by myself.

You don't have to come to these forums, it's optional.

Don't worry, it's okay to feel angry at people who prove that your ideas are wrong, even if they're right.

Terraformer · 2007-12-31 15:21:34

A space elevator would not burn up in the atmosphee as when it ell it would fall at it's maximum unpowered velocity of 37 m/s.

I don't get angry at people who prove my ideas are wrong. I get angry at people who say my ideas are wrong with no proof to back themselves up.

I've realised why I come to these forums. To find the few intelligent people who can point out flaws in my idea, explain why they are flaws (hence hy you don't fall into this category), and help me figure out how to solve them. Oh, and in the vain hope of correcting people like you, who are on a par with lschl13.

JoshNH4H · 2007-12-31 15:36:51

How about this. We call in someone not in this argument (Anyone is welcome, feel free) And ask them:

Is terraformer's idea workable?

sound fair to you?
(trying to be civil and ignoring petty insult)

Terraformer · 2008-01-06 03:37:06

Sorry for rubbishing the short space elevator idea, I found this site, which has been looked at by NASA and is apparantly the most realistic plan they have seen for cheap access to space.

JoshNH4H · 2008-01-06 13:06:07

That's kind of funny, because I scrapped it (not you, i think) when my caculations showed that it would put people in an orbit in the lower radiation belt. But...maybe that could be lowered/ raised w/rockets...

Low space elevator returned to favor

Terraformer · 2008-01-06 15:41:35

Have you read the site? If both tethers are the right length, the people would be taking in the same radiation doses people on suborbital flights and people in LEO.

JoshNH4H · 2008-01-06 16:51:36

I envision a EOSE in a 4 hour orbit, or 35% of orbital velocity at the bottom. If you'll notice, they don't say anything about that.

Terraformer · 2008-01-07 05:23:39

That's because it's just the same idea with a longer tether and different orbit for the Midpoint station.

Antius · 2008-01-07 07:19:33

I have lost the gist of this discussion. Are we talking about launching a rocket from a balloon on suborbital flights? A suborbital flight is basically a cop-out. As for using a balloon to launch rockets, we would be attempting to engineer a very complex system whose only function would be to save a little bit of mass on the lower stage of the rocket. Lower stages can be built cheaply (a la big dumb booster). There isn't really any economic advantage to launching from a balloon.

If we are serious about achieving large-scale access to space with present day technology, I would suggets that we reopen discussion on ground-launched nuclear powered spacecraft (Orion), using small and ultra-clean nuclear fusion bombs for propulsion. The radioactivity released by each launch would be small, resulting in less than one death globally. The spacecraft would mass anything from ten thousand to millions of tonnes and could carry many thousands or even millions of people into low earth orbit and beyond.

The only thing preventing the construction and use of Orion ships are political difficulties, the technical issues are more or less solved. If you want largescale access to space, this is the way to achieve it with technology available today.

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#51 2007-12-28 08:28:08

Re: Un- conventional ways to LEO

#52 2007-12-28 13:18:08

Re: Un- conventional ways to LEO

#53 2007-12-28 15:12:26

Re: Un- conventional ways to LEO

#54 2007-12-28 16:50:47

Re: Un- conventional ways to LEO

#55 2007-12-29 00:58:31

Re: Un- conventional ways to LEO

#56 2007-12-29 06:58:24

Re: Un- conventional ways to LEO

#57 2007-12-29 11:28:05

Re: Un- conventional ways to LEO

#58 2007-12-30 06:34:18

Re: Un- conventional ways to LEO

#59 2007-12-30 09:14:50

Re: Un- conventional ways to LEO

#60 2007-12-30 11:53:04

Re: Un- conventional ways to LEO

#61 2007-12-30 19:00:24

Re: Un- conventional ways to LEO

#62 2007-12-31 07:47:51

Re: Un- conventional ways to LEO

#63 2007-12-31 10:00:39

Re: Un- conventional ways to LEO

#64 2007-12-31 11:21:32

Re: Un- conventional ways to LEO

#65 2007-12-31 11:46:58

Re: Un- conventional ways to LEO

#66 2007-12-31 12:40:11

Re: Un- conventional ways to LEO

#67 2007-12-31 13:50:00

Re: Un- conventional ways to LEO

#68 2007-12-31 15:21:34

Re: Un- conventional ways to LEO

#69 2007-12-31 15:36:51

Re: Un- conventional ways to LEO

#70 2008-01-06 03:37:06

Re: Un- conventional ways to LEO

#71 2008-01-06 13:06:07

Re: Un- conventional ways to LEO

#72 2008-01-06 15:41:35

Re: Un- conventional ways to LEO

#73 2008-01-06 16:51:36

Re: Un- conventional ways to LEO

#74 2008-01-07 05:23:39

Re: Un- conventional ways to LEO

#75 2008-01-07 07:19:33

Re: Un- conventional ways to LEO

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