Space Train

[biostud]

http://www.gizmag.com/startram-maglev-to-leo/21700/

 

[TridenT]

So, I didn't read the article, but... how do they plan to support such a structure again?

IIRC, materials do not hold up well when trying to go as high as say... tens of thousands of feet...

 

[So]

Novel, active launch systems are not a new idea. Prepare to go down the rabbit hole.
http://en.wikipedia.org/wiki/Launch_loop
http://en.wikipedia.org/wiki/Mass_driver
http://en.wikipedia.org/wiki/Skyhook_(structure)
http://en.wikipedia.org/wiki/Space_fountain

More Generally:
http://en.wikipedia.org/wiki/Non-rocket_spacelaunch

Basically the problem with all of them is: They require expertise completely unlike that needed to build rockets, so the engineers doing spaceflight aren't good at it. Plus, they are radical new concepts. We know rockets work. Investing a billion dollars in a new rocket has a failure mode of the rocket being more expensive to fly than you expect. The failure more of a wholly new way of getting to space is "this will never work, due to unforseen problem X". Furthermore, the capitol costs are tens to hundreds of times higher, up front.

 

[dawp]

So, I didn't read the article, but... how do they plan to support such a structure again?

IIRC, materials do not hold up well when trying to go as high as say... tens of thousands of feet...

from the article

This new requirement begs the question - how do we hold up the exit end of the Startram vacuum tube? Well, the tube already contains superconducting cable and rings. Powell and Maise realized that the tube could be magnetically levitated to this altitude. If we arrange that there is a superconducting cable on the ground carrying 200 million amperes, and a superconducting cable in the launch tube carrying 20 million amperes, at an altitude of 20 km there will be a levitating force of about 4 tons per meter of cable length - more than enough to levitate the launch tube.

just hope you can maintain that power or it will come crashing down.

 

[Druidx]

Didn't anyone read "The Moon is a Harsh Mistress" from Robert A. Heinlein. This isn't a new idea.

"Luna must fight Terra as David does Goliath, hurling rocks."

 

[irishScott]

Ideas like this are nice, but bottom line any radical development in spaceflight either needs a spike in demand or a revolution in power generation (think cold fusion), preferably both.

 

[DisgruntledVirus]

Ideas like this are nice, but bottom line any radical development in spaceflight either needs a spike in demand or a revolution in power generation (think cold fusion), preferably both.

Get back to us on that one. Pretty sure it's junk science to say the least...

 

[SagaLore]

Its an impractical idea.

We can't safely build that large of a structure. The thing would lose its balance and come crashing down across a few cities. It would probably heavily disrupt the weather system too.

We already have a solution, I don't know why we are so resistant to pursuing it. You slowly fly the space vehicle up to the upper atmosphere then launch it the rest of the way. We could even build massive helium vehicles to just float the payload up, then cool the helium back into tanks to let the vehicle float back down.

 

[Saint Nick]

I love the artist renditions of future technologies. So stupid.

 

[irishScott]

Get back to us on that one. Pretty sure it's junk science to say the least...

I was speaking generally. Just saying we'd need something to the level of cold fusion for space travel to really take off.

 

[Soundmanred]

 

[feralkid]

 

[Newbian]

It's all fun and games until hobo's start riding it:

http://www.youtube.com/watch?v=qAmvlVMtLTw

 

[Linflas]

Didn't anyone read "The Moon is a Harsh Mistress" from Robert A. Heinlein. This isn't a new idea.

"Luna must fight Terra as David does Goliath, hurling rocks."

Many times, one of my favorites of his.

 

[MovingTarget]

Loaded like a freight train....
Flying like an aeroplane...
Feeling like a spaceplane one more time tonight....

 

[MovingTarget]

On a more serious note, I don't think a full-scale system like this would be a good idea for quite some time. However, a smaller hybrid system could make economic sense. A re-useable system to assist in launching payloads (along with rockets) could help bring down launch costs. It would launch a payload to some high initial velocity, which would rely on conventional rockets to get the rest of the way to space. This could save us considerably due to the sheer amount of weight (most of which is fuel) required in a rocket to get off the ground and reach orbital velocity.

 

[SagaLore]

On a more serious note, I don't think a full-scale system like this would be a good idea for quite some time. However, a smaller hybrid system could make economic sense. A re-useable system to assist in launching payloads (along with rockets) could help bring down launch costs. It would launch a payload to some high initial velocity, which would rely on conventional rockets to get the rest of the way to space. This could save us considerably due to the sheer amount of weight (most of which is fuel) required in a rocket to get off the ground and reach orbital velocity.

Imagine the amount of costly metals it would take to design an EM launching system, and the amount of raw electricity it would take to get the high weight payload going more than a snail's pace. They would need dedicated power plants just to charge this thing. I don't think it would be economic at all.

What we need is massive catapults. :awe::biggrin:

 

[uhohs]

 

[Newbian]

What we need is massive catapults. :awe::biggrin:

 

[bignateyk]

200 million amperes to keep it afloat? LOL

 

[MovingTarget]

Imagine the amount of costly metals it would take to design an EM launching system, and the amount of raw electricity it would take to get the high weight payload going more than a snail's pace. They would need dedicated power plants just to charge this thing. I don't think it would be economic at all.

What we need is massive catapults. :awe::biggrin:

Yeah, it would require dedicated power plants. Nuclear would be the only way to go. Perhaps once we get Fusion plants up and running this would be easier to do.

Also: Space Trebuchet :thumbsup:

 

[DesiPower]

Thanks, but I will take the elevator.

 

[SagaLore]

Hmm... I'm thinking about my helium lift idea, and now I'm thinking maybe it would be better to go with hydrogen. It would look like a huge mushroom... the massive hydrogen sack would lift the payload into the upper atmosphere, then rockets facing down from the payload would start burning the hydrogen and retracting the sack. By the time its in space all the hydrogen is gone and the sack is stored. For re-entry, they can deploy the sack which will create some drag to slow down the payload, and an air scoop would start to fill it back up. As it approaches the ground it should be descending at a safe speed. :hmm:

 

[skyking]

Hmm... I'm thinking about my helium lift idea, and now I'm thinking maybe it would be better to go with hydrogen. It would look like a huge mushroom... the massive hydrogen sack would lift the payload into the upper atmosphere, then rockets facing down from the payload would start burning the hydrogen and retracting the sack. By the time its in space all the hydrogen is gone and the sack is stored. For re-entry, they can deploy the sack which will create some drag to slow down the payload, and an air scoop would start to fill it back up. As it approaches the ground it should be descending at a safe speed. :hmm:

:awe:

Seriously, if anybody can provide me with a link explaining why we CAN'T use airplanes to launch payloads, I would appreciate it.
Half the atmosphere is below 18,000 feet. Fly a launch system up to 55,000 feet with current tech, and start out there at 550 MPH,
11 miles out of the gravity well, and above 80% of the atmosphere.

 

[irishScott]

:awe:

Seriously, if anybody can provide me with a link explaining why we CAN'T use airplanes to launch payloads, I would appreciate it.
Half the atmosphere is below 18,000 feet. Fly a launch system up to 55,000 feet with current tech, and start out there at 550 MPH,
11 miles out of the gravity well, and above 80% of the atmosphere.

IIRC, the issue is carrying enough rocket fuel on said plane to put the payload in an effective orbit. Even spaceship one, which is relatively light, was only suborbital using a plane-lift system.