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Comment by wtracy | Hacker News Reader

It's probably another case of a non-specialist reporter oversimplifying the information he was given to the point that the summary is no longer correct.

Hobbyists have sent balloons to "space" at 100,000 feet <http://www.brooklynspaceprogram.org/>; though that obviously isn't going to get you into orbit.

Groups like CU Spaceflight are experimenting with launching rockets from high-altitude balloons. The idea is that the balloon will get you through most of the atmosphere for dirt cheap, hopefully bringing launch costs down within the reach of private citizens.

A project like that could put a satellite in space using a balloon, just not in the way that you're thinking of. :-)

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I've read a lot of technical stuff about rockets and space missions lately to the point of hurting my brain. I am not a rocket scientist (yet ;-) but I think what one needs is to launch a single robot in orbit while more components are sent to be assembled up there with balloons e.g. to build a unmanned space station. Could that work?

"... launch a single robot in orbit while more components are sent to be assembled up there with balloons e.g. to build a unmanned space station. Could that work?"

No. What could work, with regard to a space station, is to send up thousands of robotic panels, and insert them into orbit at roughly the same spot. They would communicate with each other to figure out where they are in relation to one another, and then they would, one pair at a time, fire their own thrusters to come together, and permanently join with each other, to form not only the space station itself, but also the station's distributed computing system and sensor network. The robots might even go further, by generating an atmosphere, thus allowing for the station to be occupied by humans. We already have the ability to easily send up such robots, by using Orbital's Pegasus, which is launched by a modified L-1011 from 40,000 feet. All we really need is to design, build and test the robots, such that each is no more than 1,000 pounds, as well as scale up the process of building and launching those rockets, which is covered below, in an article by John Walker, co-author of AutoCAD.

http://www.orbital.com/spacelaunch/pegasus

http://www.fourmilab.ch/documents/rocketaday.html (A Rocket a Day Keeps the High Costs Away)

No. You'd avoid friction. You may be able to accelerate faster, meaning less waste (as you won't be fighting gravity for as long). And you'd gain potential energy by already being up so high. But there's still a minimum amount of energy you need to get to orbital velocity.

If you didn't burn fuel to match speeds, you'd smack into the robot, which will be moving at orbital velocity.

See, the way a satellite stays "up" is by moving really fast in a straight line perpendicular to the earth's surface, like this:

satellite earth

   ^-> falls "down"
   |      /
   |      |
 d-0-b    |
          |
          \

The satellite "falls" towards the Earth, but it's moving so fast that this "falling" just becomes part of a giant circle, around the earth. If it was any faster, it would shoot away (or move to a higher orbit). If it was slower, it would fall down to a lower orbit, and if it was too slow it would hit the atmosphere where it slows down even more (eventually crashing down).

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