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2
votes
0answers
180 views
+100

Exact speed/distance of JWST (& others in L1/L2 halo) from Earth; is it measured any differently than for more distant deep-space missions?

How is the exact speed and distance from Earth of the JWST or any spacecraft in a Sun-Earth L1/L2 halo orbit determined? While deep space missions require ranging at hundreds of millions of kilometers ...
3
votes
0answers
42 views
+100

Fjeldbo, Kliore, & Eshleman 1971 Fig. 22 planetary atmosphere index of refraction increasing with altitude; physics insight or convenient abstraction?

this answer to Is it possible for a spacecraft to communicate with Earth when a planet is in the way? suggesting that atmospheric refraction could be used to get at least some kind of signal around a ...
7
votes
0answers
213 views
+50

Would it be possible to receive the transmissions from JWST as an amateur?

Would it be possible to receive the transmissions from JWST (James Webb Space Telescope) as an amateur, building your own antenna? Would the transmissions be encrypted? One source cites it using: S-...
4
votes
0answers
300 views
+200

Why is DSCOVR in a Lissajous orbit? Wouldn't a halo orbit completely avoid the Sun exclusion zone?

Halo orbits are a sub-class of Lissajous orbits. See this answer for (much) more on that. DSCOVR's orbit will put it in it's Sun Exclusion Zone in about 2020 where the communications line of sight ...