| Size: 2535 Comment:  | Size: 2535 Comment:  | 
| Deletions are marked like this. | Additions are marked like this. | 
| Line 29: | Line 29: | 
| || #H / m³ || 2.1e10 || 1.2e10 || 3.1e9 || 8.2e8 || 1.8e8 || 6.7e7 || 4.5e7 || 3.5e7 || 1.4e7 || 1.1e7 || 1.0e7 || | || #H / m³ || 2.1e10 || 1.2e10 || 8.2e8 || 1.8e8 || 6.7e7 || 4.5e7 || 2.2e7 || 3.5e7 || 1.4e7 || 1.1e7 || 1.0e7 || | 
Propellant Plume Gas Scattering
H density versus altitude
|   | alt km | radius km | #/m3 | 
| 1000 | 7378 | 21000e6 | |
| 2000 | 8378 | 12000e6 | Constr. perigee | 
| 5000 | 11378 | 3100e6 | |
| 10000 | 16378 | 820e6 | |
| 20000 | 26378 | 180e6 | |
| 30000 | 36378 | 67e6 | |
| 35786 | 42164 | 45e6 | GEO circular | 
| 40000 | 46378 | 35e6 | |
| 50000 | 56378 | 22e6 | |
| 60000 | 66378 | 14e6 | |
| 69572 | 75950 | 11e6 | Constr. apogee | 
| 70000 | 76378 | 10e6 | |
. https://www.sciencedirect.com/science/article/pii/0022407372900052
| Estimated hydrogen mass per 1000 km height, 1.67e-27kg/H | |||||||||||
| Altitude km | 1000 | 2000 | 10000 | 20000 | 30000 | 35786* | 40000 | 50000 | 60000 | 69572* | 70000 | 
| Radius km | 7378 | 11378 | 16378 | 26378 | 36378 | 42164* | 46378 | 56378 | 66378 | 75950* | 76378 | 
| Volume km³ | 6.8e11 | 1.6e12 | 3.4e12 | 8.7e12 | 1.7e13 | 2.2e13 | 2.7e13 | 4.0e13 | 5.5e13 | 7.2e13 | 7.3e13 | 
| #H / m³ | 2.1e10 | 1.2e10 | 8.2e8 | 1.8e8 | 6.7e7 | 4.5e7 | 2.2e7 | 3.5e7 | 1.4e7 | 1.1e7 | 1.0e7 | 
| H kg | 24000 | 32000 | 18000 | 12000 | 5100 | 2500* | 2300 | 2300 | 1300 | 1300* | 1200 | 
Less than 20 tonnes of hydrogen (and almost nothing else) above GEO, out to the bow shock.
Collision cross section table
| Gas | (nm)² | (nm)² with H₂ | 
| H₂ | 0.27 | 1.02 | 
| He | 0.21 | 0.99 | 
| Ar | 0.36 | 1.06 | 
| O₂ | 0.40 | 1.07 | 
| N₂ | 0.43 | 1.08 | 
| CH₄ | 0.46 | 1.09 | 
| CO₂ | 0.52 | 1.11 | 
| Cl₂ | 0.93 | 1.22 | 
The second column is the combined collision cross section with an H₂ molecule ... the square of the sum of the square roots.
from libretexts
- http://hitran.org . . . . . . . . . k*l at k*l dot com on kao3 

