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Let's assume that there is a way to travel into space that's not in a rocket, and a human can essentially just walk/be carried into the upper atmosphere and beyond.

Would there be anything that, physically, would stop a human traveling into space from Earth at a reasonable pace on a escalator/elevator? There is no outer shell on the transportation to protect the person from the harshness of space. It would be more like a paternoster than an actual enclosed elevator.

This device is attached to a man-made satellite station in geo-stationary orbit. It is just outside of our atmosphere and serves the best sushi anywhere. Don't ask how they get the fresh fish.

Let's assume that the person is wearing a space suit like the one Felix Baumgartner wore to go into space, but more advanced and longer-lasting so the person can survive in it for however long it takes to reach somewhere safe that they can rest. It allows the person to survive the change in pressure and temperature from the Earth's surface to the space station.

How far would this person be able to get? That is, how high up could this space station reasonably be that a human could reach it? If the perfect transportation and space suit and space station exist, could a human escape from Earth's atmosphere on their own for as long as it takes the oxygen to run out? Or are there other considerations for a human exiting the atmosphere?

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    $\begingroup$ How is this different from a space elevator except that the person moving is the one providing power? $\endgroup$ – ratchet freak Apr 20 '15 at 14:57
  • $\begingroup$ Space elevators are currently not possible due to lack of tensile strength of our current materials. So your ladder wouldn't be possible either. $\endgroup$ – ratchet freak Apr 20 '15 at 15:02
  • $\begingroup$ What about a rope? (Or cable with one of those brake/handle thingies) $\endgroup$ – Spacemonkey Apr 20 '15 at 15:11
  • $\begingroup$ You can't have the combination of geostationary orbit and Earth's atmosphere. As the answers to space.stackexchange.com/q/5163/415 explain, GEO is merely the balance point (point of center of mass) for a space elevator anchored on the surface, so it would need to extend further than to GEO to be balanced. Even at the ~10km altitude that airliners fly at, an unprotected human will die both from the cold as well as the lack of oxygen, but it's still low enough to support aircraft, so not orbitable in any sense. $\endgroup$ – a CVn Apr 20 '15 at 16:29
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    $\begingroup$ what-if.xkcd.com/126 $\endgroup$ – Loren Pechtel Apr 20 '15 at 18:08
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A sufficiently good spacesuit is essentially a spacecraft in and of itself. There is thus nothing to prevent a person from being bodily lifted into space, as long as the suit is good enough.

Wind speeds get really high at high altitudes, though. Such a person had better brace him or herself really well.

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This document seems to indicate that a typical escalator is inclined at 30 degrees and has a speed of around 100 feet per minute. This gives a vertical speed of about 0.25 meters per second, or 0.57 miles per hour. The corresponding slowness is around 105 minutes per mile. We'll take that as the vertical speed of your space escalator.

At first, it seems that we just need to make it to the Kármán line at 100 kilometers. Assuming you start at sea level, it would take around four and a half days to reach space. Note how I didn't say "reach orbit": Although you'd be at the correct altitude, you'd be around 8 kilometers per second short of the right speed.

The altitude at which you'd be at the correct speed is geostationary orbit, 35,786 kilometers. At escalator speed it'd take around 4 years, 5 months to reach this altitude. The additional problem is that you'd get a high radiation dose from going through the radiation belts and outside the Earth's magnetic field. (The dosage level would be around 100 times the limit for radiation workers.)

Considering that current space suits have around 8 hours of life-support capacity anyway, you'd only make it 12,000 feet before you had to turn back; enough to climb Mount McKinley starting at the base, or to climb Everest starting from one of the base camps, but not enough to get to space.

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    $\begingroup$ I'm pretty sure they'd get that thing going faster than a walking pace... $\endgroup$ – Rob Watts Apr 21 '15 at 22:19
  • $\begingroup$ @RobWatts I interpreted "at a reasonable pace on a escalator" to mean reasonable for an escalator, not necessarily reasonable for space. You'd need about a 15x speed increase to make it to 100 km, and a 5000x increase to make it to geosynch (both one-way only). $\endgroup$ – 2012rcampion Apr 21 '15 at 22:31
  • $\begingroup$ I read it as "traveling into space from Earth at a reasonable pace" with the escalator/elevator being the means of travel. Still, I do like how this gives you a sense of the scales involved. You should add the 15x and 5000x bit into your answer. $\endgroup$ – Rob Watts Apr 21 '15 at 22:38
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Most reasonable projections of space elevator technology suggest that the elevator car will be moving through the Van Allen radiation belts for a prolonged period of time, making it hazardous for human and live cargo unless the elevator car is heavily shielded, which will dramatically reduce payload or reduce the speed of the elevator car be a large amount (or make the energy cost of raising an elevator car extremely high). And this is with a powered climber device, essentially a space capsule riding up the elevator cable.

Humans can survive so long as they are protected from radiation, extremes of heat and cold, have a pressurized environment and sufficient food and water to last the trip. A space elevator with proper design can provide all these, and have a very gentle acceleration as well. Most common ideas for space elevators have platforms at various heights above the Earth for various purposes (observation decks, releasing payloads into various orbits), but the two most important platforms are at Geostationary orbit, and at the far end of the elevator. Geostationary orbit is fairly straight forward, you can simply push off from the elevator and with a minimum of rocket power reach any point in geostationary orbit that allows you to observe the desired area (communications satellites with huge antenna will be able to send and receive signals from your smartphone, for example.)

Depending on how far the end of the elevator extends, a payload released there would be provided with the energy of Earth's rotation, and a sufficiently long elevator could in theory fling loads to Saturn on minimum energy orbits. In reality, a practical design might be shorter, using a large counterweight on the end of the elevator cable to keep everything in tension, so your release velocity will depend on just how far past geostationary orbit the cable ends. Flinging payloads to Mars seems reasonable.

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The distance involved is too long to realistically expect people to walk/climb it. Most plans for a space elevator have exactly that - pressurized cabins that climb up the cable. Usually there would be a row climbing on one side and descending on the other.

Manned elevators would be pressurized, but cargo ones might well not be. In that case it would be possible to put on a space suit and climb onto a cargo elevator and get carried up into space.

You would need a large oxygen supply to last for long enough as even without using your legs it would still be a long journey. You would see the ground sinking away further and further. The sky would get darker and darker as the atmosphere thinned while the horizon would start to curve.

Eventually you would see the circle of the earth dropping away beneath you and just the darkness of space lit by stars above.

But so long as you had a long enough duration space suit it would be entirely possible, and apart from the spectacular view, rather boring and uneventful.

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  • $\begingroup$ I doubt that: given the necessary equipment, some people will come to see it as a challenge. Why do people climb Mt. Everest, run ultramarathons, or through-hike the Appalachian & Pacific Crest trails? $\endgroup$ – jamesqf Apr 21 '15 at 18:56
  • $\begingroup$ The OP specifically mentions an escalator/elevator, no climbing necessary. $\endgroup$ – 2012rcampion Apr 21 '15 at 21:43

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