AERSP/STS 055 Space Science & Technology 

Lecture Notes 
Space Stations
Spinning section was a hollow toroid (doughnut). Hollow tubes connected it to the central hub (nonspinning) via an elaborate mechanism that joined the spinning and nonspinning sections. Various airtight 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 a_{c} = v^{2}/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 a_{c} = 4p ^{2}(0.05)^{2}(30) = 2.9 m/sec^{2}
On Earth, normal gravity is 1 g (which is 9.8 m/sec^{2}), so
a_{c} = (2.9 m/sec^{2})/(9.8 m/sec^{2}) = 0.302 g
 On a really large space station,
R = 806 m. (about half a mile!)
S = 1 rot/57 sec = 0.0175 rot/sec.
So a_{c} = 9.8 m/sec = 1 g
 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/s^{2} = 2.94 m/s^{2}
2.94 m/s^{2} = 4p ^{2 }S^{2 }R = 39.48 S^{2} ´ 150 m.
S^{2} = 2.94 m/s^{2} / (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 (m^{3}) 
Power Generated (kW) 
Core 
20900 
13.13 
90 
10.1 
Kvant 
11050 
5.8 
40 
None 
Kvant2 
18500 
12.4 
61 
6.9 
Kristall 
19640 
11.9 
61 
5.58.4 
Spektr 
19640 
12 
62 
6.9 
Priroda 
19700 
12 
66 
none 
TOTALS 
109430 

380 (PSU dorm room has 9.5 m^{3}) 
29.432.3 
Copyright © 1998, Robert G. Melton
Updated Wednesday, 21Jan2004 10:04:50 EST
AERSP/STS 055 Space Science & Technology 