I recently watched the series Altered Carbon. In that series, they showed a floating space station called "Head in the Clouds". Space station with a blue sky There is a blue sky here, even clouds. This would imply a height of <15km. It seems to be kept up solely using thrusters.

Let's say we want to put a space station into orbit at 18km. The orbital speed at this height would be 7.9km/s. However, it would suffer orbital decay. Even the ISS does at a height of ~400km, and according to Wikipedia altitudes below 160km will suffer "very rapid orbital decay"Wikipedia.

So the question is; how much acceleration would be required to counter this orbital decay and keep a space station in orbit at 18km? How about the mesosphere? What is the function for acceleration required at a given height to keep it in orbit (i.e, orbital decay as a function of altitude)?

  • 3
    $\begingroup$ 1) That orbital speed cannot be right. km/s? 2) Your station would be a plasma trail in seconds. $\endgroup$ – Organic Marble Feb 28 '18 at 14:26
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    $\begingroup$ In the show, the flying "Head in the clouds" is not actually in orbit. It just hovers over a specific spot. Orbiting at 18 km height in the traditional sense isn't really possible as air friction would disintegrate basically anything traveling at an orbital speed. Traveling at 7.9 -km/s- is the equivalent of 28440 kmh or mach 23--the current speed record by military jets is only a mere mach 6.8 $\endgroup$ – Dragongeek Feb 28 '18 at 14:54
  • $\begingroup$ Related $\endgroup$ – Manu H Feb 28 '18 at 17:32

As noted in comments, if it’s in significant atmosphere, it needs to be essentially stationary relative to the atmosphere; even 100m/s speed implies beyond-hurricane-force winds tearing at those delicate cables and signage. So it’s stationary relative to the atmosphere, thus stationary relative to the surface, therefore it needs approximately 1g of constant vertical acceleration to hold position against gravity’s pull.


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