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What's your favorite method of space launch or travel? (realistic only please)


Mr Skeptic
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A cannon, by itself cannot work for orbital insertion. See the reference in Mr. Skeptics post # 20: http://www-istp.gsfc.nasa.gov/stargaze/SSHARP.htm

 

...by Kepler's first law, any orbit is an ellipse with one focus at the Earth's center. If the payload is launched from point A on the Earth's surface, by necessity its orbit intersects the surface again at a symmetrically placed point B. An orbital adjustment is therefore essential.

 

The cannon/rail gun/etc. must be used to either acheive an escape velocity (and therefore there is no orbit), or must be supplemented by something else (such as a rocket) if orbit is desired.

 

Edit: Although, I suppose the ability to launch from the moon such that lunar escape is reached could be used to insert satelites into earth and/or solar orbit. Could this make it cheaper at some point to manufacture satelites and space probes on the moon rather than on earth?

Edited by SH3RL0CK
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  • 3 weeks later...

I don't forsee it being too difficult to get such a package relatively close to light speed, with a rather loose definition of "relatively" (and no pun intended). Half light speed? 75% light speed? It's certainly better than what we could do with a spaceship containing a large and fragile human.

Edited by swansont
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Could this gun be scaled up by a factor of 4 to 5? I would think there is a reason why rockets and not guns were attempted for the first space flights in the 1950's and 1960's...but I'm not sure these reasons mean a cannon must be impractical.

 

I can see two reasons why a rocket was used for the first space flight:

 

If you attempt to put a 10 kg satellite in orbit, a rocket is simple. The cannon is a lot bigger than the rocket. I think a 5-10 km barrel is realistic. The rockets were only 50 meters tall.

However, if you attempt to put a thousand 10 kg satellites in orbit, a cannon is might be simpler.

 

In the 1950's and 1060's, the goal was to put a single satellite in orbit. Nowadays we want as many as possible.

 

Also, in the 1950's and 1060's, the technology wasn't so robust that a radio transmitter could survive 1000 G acceleration. Nowadays this is entirely possible.

 

[edit] And as SH3RLOCK correctly points out, a satellite would still require an engine (though a lot smaller (?)) to correct its trajectory and to get into a proper orbit that does not intersect with the earth itself... unless the escape velocity is achieved.

Edited by CaptainPanic
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What about solar sails? Of course these would only work once you exited the atmosphere but it would be a much more efficient way of space travel.

I think solar sails lose efficiency the further away from the sun you go.

Also, I think that space dust eventually will destroy them?

but you're right that they require zero fuel, yet still provide some acceleration. It's hard to beat that in terms of efficiency.

 

However:

The following part of my response is totally subjective (meaning that it's my opinion, and it's not based on any science or valid reasoning):

Personally I hope we won't be sailing through space. I'd rather have us get a cheap way to get lots of fuel into space. Big engines. Lots of steel. And a jacuzzi on board. I also find formula 1 more attractive to watch than the world solar challenge. It's more fun to see a sprint than a marathon. And I rather have a steak than a carrot.

 

I hope we'll go into space in big, bulky, steel machines. I'd rather waste some fuel in space (no greenhouse problems there anyway) than save on weight if I have to spend an eternity up there.

In other words: I'd rather have this one than this one. This one is good, and this one I don't like.

The ships with huge glowing exhausts look fine to me. Why save on weight if you can also blast another ton of fuel into orbit cheaply (or better: when you can create it in orbit)? Bigger is better anyway.

If one engine isn't enough, add another one. If one fuel tank isn't enough, add another one. With a staged design, there is no limit.

 

A sail is just annoying. It's very slow, will easily break, doesn't attract girls, doesn't work far away from a star and you can't see a damned thing of where you're going half the time because your sail is blocking your view...

Edited by CaptainPanic
more subjective ranting :)
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A sail is just annoying. It's very slow, will easily break, doesn't attract girls, doesn't work far away from a star and you can't see a damned thing of where you're going half the time because your sail is blocking your view...

 

That assumes that the sail is opaque to the entire electromagnetic spectrum. ;)

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Actually solar sails are not slow at all. But I think it would be important to have a plethora of different propulsion systems available on future space-craft because different systems are better at different times.

 

IE) if your rockets ran out of fuel it would be nice to have a solar sail rather than not having one.

 

As for getting girls maybe we could design a space-craft that uses a good old v8-hemi or corvette engine lol, even get a manual tranny on that. And captain your post made me laugh pretty hard haha.

Edited by toastywombel
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Yes, I've considered that for the future of space travel. It would be ideal once we develop nanorobots. So far, it seems like it would have to be far into the future. Also, you will need to make your rocket big enough to survive space radiation and collisions with particles. Also, you will be wanting to decelerate so as not to vaporize at the destination.

 

All of that could be solved by surrounding the ship with a plasma field, among other things.

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