Linked Questions
20 questions linked to/from How is the altitude of a satellite defined, given that the Earth is not spherical?
1
vote
1
answer
800
views
How large would be the seasonal variation of eclipse duration for a spacecraft in LEO?
The question How long will a 500 km altitude satellite spend in Earth - shade per orbit has several answers, and there is some discussion of constraints related to maximum eclipse, due to some issues ...
- 149k
5
votes
2
answers
568
views
Did Tiangong-1 turn the engines on?
The following graph shows the Tiangong-1 radius vector at the perigee, semi-major axis and apogee (scaled to 6371 km just to show an approximate altitude) and its orbit eccentricity:
I used the SGP4 ...
- 1,760
1
vote
2
answers
933
views
What is the Fischer 1960 Mercury Ellipsoid, and why is it called that?
Don't be distracted by the 1960 Mercury shown below. Reading about Irene Fischer (also here, and mentioned in this answer) and seeing the Fischer 1960 Mercury Ellipsoid turn up in tables of ellipsoid ...
- 149k
6
votes
3
answers
4k
views
Determine orbit type from TLE
I was wondering if, and how, one can tell from the values in a TLE whether an orbit is LEO, MEO, HEO, or GEO. I'd like to do this in code eventually, so any formulas or threshold values would be much ...
- 63
9
votes
2
answers
5k
views
In "spacecraft talk" is nadir just a fancy word for "down"?
Assume the approximation that the Earth is spherically symmetric — without higher order gravitational multipoles, and other effects that might be related to gravity from other bodies or the ...
- 149k