Space Elevators Could Be Lethal

Maggie McKee writes, "A new study reports that passengers on space elevators of current design could be killed by radiation. Even traveling at 200 kilometers per hour, passengers would spend several days in the Van Allen radiation belts, long enough to kill them." Looks like the elevator scientists will get this one solved before liftoff.

Aqua viva

[TheSHAD0W]

One of the most popular (and massive) items that will need to be shipped to orbit will be water; and water makes a good shield against radiation. Just make your passenger cars with a living unit inside a larger freight unit, and fill the gap in between with water. If you used filtered fresh water you could even have windows on both walls and be able to look through.

Rockets?

[Odin_Tiger]

How much thrust would a rocket need to zip you through those sections if you waited to fire it until reaching, say, 500 - 800km? Surely by then you'd be far enough away from Earth that a little bit of push would go a long ways, compared to firing a rocket from the ground?

Re:Aqua viva

[malsdavis]

Many water companies already treat tap water with gamma radiation to remove things like bacteria.

Radiation - unlike radioactive particles - won't cause any further radioactivity within water.

C'mon, COMMON SENSE!

[ShooterNeo]

Why do people even waste their time on this idea. WHY DO WE NEED SPACE ELEVATORS?

For all the engineers here: why would you want to build a cable tens of thousands of miles long out of currently UNAVAILABLE materials (unobtanium) to slowly ratchet up one payload at a time? It's a horrid idea, and it STILL takes just as much actual energy to put anything in orbit...just it does so pathetically slowly.

The plan is to use PHOTOVOLTAIC PANELS to receive the energy being beamed from the ground. That is a patheticaly slow method of energy conversion considering the payload still has to receive the equivalent energy of being accelerated to several miles/second!

There's a simple and really OBVIOUS idea that has been on the drawing board for at least a decade. It would involve a heck of a lot less work, be likely much simpler and cheaper, and be flat out cool.

Instead of building just a few lasers to beam the energy, lets make a whole bunch of them and use the latest electrically powered pulse laser technology being developed for the joint strike fighter. Our spacecraft is just a payload module with stabiliers BOLTED to a block of inert material. A very short and simple linear accelerator kicks the spacecraft about half a mile into the air, high enough for all the lasers spread across the industrial plant infrastructure to 'see' it.

Pulses of light vaporize the fuel in a sequence such that the shock wave of superheated vaporized gas is planar : basically a rocket engine without needing :

A nozzle pumps, combustion chambers, volatile fuel, electrical systems, elaborate control systems and sensors, just enormouse amounts of hardware gets taken out of the spacecraft and left sitting on the ground. Sure, there's a LOT more delicate hardware left sitting on the ground...WHERE IT BELONGS. The laser launch system would be designed for almost continuous duty, launching one capsule after another all day long. Spacecraft would be MUCH simpler, and with a lower cost of launch could be made MUCH more cheaply as well. After all, why bother with all the checks and cleanrooms if you can send 10-20 Mars probes for the price of what 1 costs today? No need to shave every gram if launches only cost about 20 bucks a kilogram instead of about 1-10 thousand.

And finally, after testing this laser launch system by actually launching thousands and thousands of missions to find out what the REAL failure rate is, and gradually scaling it up to launch bigger, but just as simple, spacecraft we use it for manned missions as well.

  Seems like a no-brainer approach. I think the current planning for space travel is like trying to transport goods by horse and buggy across the continent on a massive scale when the same money could be used to install a railroad.

Re:C'mon, COMMON SENSE!

[TheSHAD0W]

Blasting something up with lasers is less expensive than using mechanical coupling. Though I agree, putting solar panels on the cars to power them is sort of silly. I'd run parallel rails up the beanstalk and let the cars tap the electricity.

There's something else you've overlooked: A car coming DOWN can use regenerative braking and feed power INTO the rails. If we're going to be mining for metals in space, we might wind up generating more electricity from the cars coming down than we'd spend in bringing cars UP. Net profit, even before selling the metals.

Re:Feces?

[TheSHAD0W]

Actually, feces would probably be a huge commodity in space; it'd be invaluable as fertilizer for the farms.

And no, I'm not joking; if farms are at all feasible, you'd want them, not just to supplement the diet of the population in space, but also to regenerate oxygen from carbon dioxide.

Earning the Penthouse Suite

[Doc Ruby]

Why would I travel at only 200KPH? How about 2000Km:h, on an engineered track, through the near-vacuum past 100-200Km out? Space is an acceleration game, so really I'm concerned only with how long I have to spend under the crush. At 1G, I could get to 2Mm:h (Megameters per hour) in under 1 minute. 15 minutes through the atmosphere, another minute up to 2Mm:h, then a couple of hours to the top (another 1.5G deceleration for a minute) once friction is immaterial. At 1.5G all the way up halfway, then slowing 1.5G the rest of the way, that's 2 minutes [cthreepo.com] to the top. I don't know if I'd want to fry on a daily commute, but why live with Earth limits when we're leaving the Earth?

The other solution they're not considering in that article is to engineer the elevator car to travel inside the cable, rather than outside. Use the mass necessary for tensile strength for radiation shielding, too.

These are 30 second solutions. I'm sure the next decades before we actually deploy the spacehooks will find lots of better solutions.

Re:Aqua viva

[Squalish]

Yes [yahoo.com].

Heavy water is unable to sustain cell division, by not forming hydrogen bonds necessary for our biochemistry with the same ease. But apparently, it doesn't really interfere either.

Re:Math error?

[drsquare]

What's to stop space stations etc being tethered to the cable?

Re:Aqua viva

[meringuoid]

But how do you avoid the radiation on the way back down? Free fall?

Sure, why not? It worked for Apollo. The expensive part of a spaceflight is liftoff, and that's where a space elevator really helps. Even if you've got to bring along a capsule to come home, you've still saved the costs of a Bloody Huge Rocket to get to orbit in the first place.