Differences between revisions 25 and 43 (spanning 18 versions)

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
image source

. 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	3.5e7	2.2e7	1.4e7	1.1e7	1.0e7
H kg	240000	32000	4700	2600	1900	1700*	1000	1500	1300	1300*	1200

Less than 20 tonnes of hydrogen (and almost nothing else) above GEO, out to the bow shock.

Note: 75950 km radius is the apogee of a "24 hour" geosynchronous (but NOT geostationary) orbit with a 8378 km radius (2000 km equatorial altitude) perigee. The same 42164 km semimajor axis as a circular geostationary orbit. This is a High Eccentricity Earth Orbit (HEEO), suggested by space scientist John Lewis at the University of Arizona. Given the high perigee velocity of a launch loop, this orbit is easier to achieve with much less apogee insertion ΔV than a GEO orbit. The perigee velocity of this HEEO orbit is high, and that is an excellent place for a high ΔV thrust into an interplanetary orbit. Subnote: due to the J₂ nonlinearity of the Earth's gravity field, this orbit will precess, so an exact sun-synchronous orbit will have a slightly smaller semimajor axis.

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

-  ⇤ ← Revision 25 as of 2019-09-18 16:11:52 → 
  Size: 1693
  Editor: KeithLofstrom
  Comment:
+   ← Revision 43 as of 2020-08-27 07:32:13 → ⇥
  Size: 3326
  Editor: KeithLofstrom
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
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- . http://hitran.org . . . . . . . . . keithl@keithl.com on kao3
 
 . https://www.sciencedirect.com/science/article/pii/0022407372900052
+-------
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-H density versus altitude:
+=== H density versus altitude ===
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-||<|14> {{ attachment:geocoronaMarkup.png | | width=600 }} ||<)> '''alt km''' ||<)> '''radius km''' ||<)> '''#/m3''' ||
+||<|16> {{ attachment:geocoronaMarkup.png | | width=600 }} ||<)> '''alt km''' ||<)> '''radius km''' ||<)> '''#/m3''' ||
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+. https://www.sciencedirect.com/science/article/pii/0022407372900052
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+Line 24:
-from [[ https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Kinetics/Modeling_Reaction_Kinetics/Collision_Theory/Collisional_Cross_Section | libretexts ]]:
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-||<-3> Collision cross section    ||
+||<-12> 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  || 3.5e7  || 2.2e7  || 1.4e7  || 1.1e7  || 1.0e7  ||
|| H kg        || 240000 ||  32000 ||  4700  ||  2600  || 1900   || 1700*  || 1000   || 1500   || 1300   || 1300*  || 1200   ||

Less than 20 tonnes of hydrogen (and almost nothing else) above GEO, out to the bow shock.

Note: 75950 km radius is the apogee of a "24 hour" geosynchronous (but NOT geostationary) orbit with a 8378 km radius (2000 km equatorial altitude) perigee.  The same 42164 km semimajor axis as a circular geostationary orbit.  This is a High Eccentricity Earth Orbit (HEEO), suggested by space scientist John Lewis at the University of Arizona.  Given the high perigee velocity of a launch loop, this orbit is easier to achieve with much less apogee insertion ΔV than a GEO orbit.  The perigee velocity of this HEEO orbit is high, and that is an excellent place for a high ΔV thrust into an interplanetary orbit.  Subnote: due to the J₂ nonlinearity of the Earth's gravity field, this orbit will precess, so an exact sun-synchronous orbit will have a slightly smaller semimajor axis.

===  Collision cross section table ===
-Line 39:
+Line 49:
+from [[ https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Kinetics/Modeling_Reaction_Kinetics/Collision_Theory/Collisional_Cross_Section | libretexts ]]

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 . http://hitran.org . . . . . . . . . k*l at k*l dot com on kao3

Diff for "GasScatter"

Propellant Plume Gas Scattering

H density versus altitude

Collision cross section table