Lecture Notes
Updated Wednesday, 21-Jan-2004 10:04:50 EST

Space Stations

Spinning section was a hollow toroid (doughnut). Hollow tubes connected it to the central hub (non-spinning) via an elaborate mechanism that joined the spinning and non-spinning sections. Various air-tight hatches allowed different sections to be sealed in the event of a leak.

 

 

A popular amusement park ride consists of a cylinder that spins around a vertical axis. People stand with their backs to the inside wall and the cylinder spins up. Once it's going fast enough, the floor drops away and everyone is stuck to the wall by the artificial gravity. What's really happening is that the cylinder wall is exerting a force (centripetal force) to keep everyone moving on a curved path (in this case, a circular path). But to the people or any other object in the cylinder, the effect is the same as if there were a force pushing them outward (called the centrifugal force) -- that's the artificial gravity.

where S is the spin rate (in rotations/second) and R is the distance from the center (of the spinning section) out to the point of interest (usually where the astronaut is).

Note: this formula looks different from the one in the textbook, where one uses the velocity v at distance R from the center and the formula is ac = v2/R. But v is just 2p SR, so a little algebra shows that the two formulas represent the same thing.

S = 0.05 rot/sec

So ac = 4p 2(0.05)2(30) = 2.9 m/sec2

On Earth, normal gravity is 1 g (which is 9.8 m/sec2), so

ac = (2.9 m/sec2)/(9.8 m/sec2) = 0.302 g

  • On a really large space station,
  • If R = 150 m., what spin rate is required to produce an artificial gravity of 0.3 g

        0.3 g = 0.3 x 9.8 m/s2 = 2.94 m/s2

        2.94 m/s2  = 4p 2 S2 R = 39.48 S2 150 m.

        S2 = 2.94 m/s2 / (39.48 150 m.) = 4.96 10-4 (rot/sec)2

        S = 0.022 rot/sec.  (or approx. 1 rotation every 45 seconds)

Floor -- dark green carpet

Walls -- light green

Ceiling -- white w/fluorescent lamps


 

Summary of Mir's Modules

Module

Mass (kg)

Length (m)

Habitable Volume (m3)

Power Generated (kW)

Core

20900

13.13

90

10.1

Kvant

11050

5.8

40

None

Kvant-2

18500

12.4

61

6.9

Kristall

19640

11.9

61

5.5-8.4

Spektr

19640

12

62

6.9

Priroda

19700

12

66

none

TOTALS

109430

 

380

(PSU dorm room has 9.5 m3)

29.4-32.3

  • Mir deorbited on March 23, 2001. Although most of its 147,000 pounds burned up in the atmosphere, approximately 50,000 pounds reached the South Pacific Ocean.


  •    Photo of Mir's remaining modules as they passed over Fiji during the descent


  • Animated simulation of Mir's descent and breakup, based upon simulation data from the Russian Space Agency. This animation was creatd by Analytical Graphics, Inc., using Satellite Took Kit.
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