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1

Neither NASA nor Xinhua news, in their detailed descriptions of the overall mission, mention any role for the orbiter after the returner separates from it in Earth orbit to land. Any extended mission for the orbiter that requires equipment beyond what is needed to retrieve Lunar samples would have eaten into the payload budget and probably reduced the size ...


3

There is an issue with geosync orbit: You are in the outer Van Allen radiation belt. Oodles of relativistic electrons running around. Your space craft has to be shielded against those. If you parked at geosync orbit, then you'd receive about 25 Sieverts of radiation per year -- about 5 times lethal dose. Even that requries a 3 mm protective shell. Solar ...


5

To be stationary above ground we need an orbit with a period of about 24 hours ( exactly 23 hours, 56 minutes and 4 seconds, one sideral day). Such an orbit is called GEO and is 35,786 km above ground). Many communication and TV satellites are placed into a GEO orbit. We have rockets for the transfer of astronauts to the ISS into a LEO orbit. But we don't ...


2

For an object in orbit to remain at the same position relative to a point on the ground, it needs to be in geostationary orbit, i.e. at an altitude of 35,786 km, and directly over the equator. That orbit is quite densely occupied by a large number of satellites, so they would have to find an available spot. That orbit is also a much higher orbit that that ...


1

Sure these are possible. One would be a crew-containing capsule in Geostationary orbit. One might park there for some reason, perhaps waiting to meet another spacecraft with its fuel already in space, another might be to do some inspections, repair, "spacecraft archaeology1 for historical purposes" (i.e. spying or snooping) or even some outright ...


1

In 1986, Giotto closely approached Halley's comet flying through dust and gas and surviving with less damage than expected. I couldn't tell if Giotto was flying through Halley's tail or coma, but its journey can be taken as an upper bound of how harsh flying through the tail can get.


10

The International Cometary Explorer spacecraft passed through the plasma tail of 21P/Giacobini–Zinner in September, 1985, which I think was the first time the human race had engineered such a rendezvous. Many years ago, in my salad days, I did my PhD research on the encounter.


24

Ulysses, the shuttle-launched joint NASA/ESA probe to study the sun's polar regions, ran through three comet tails, more or less by chance. Ulysses Catches Record for Catching Comets by Their Tails ...comet Hyakutake ...On May 1, 1996, while Ulysses was cruising through space studying the solar wind, its data suddenly went wild for a few hours. The once-...


11

The two Vega probes comes to mind, ending their implausible sounding mission of slipping balloons into the atmosphere of Venus with a flyby of Halley's comet in 1986. They took a heavy beating flying through the coma, which is the shell of dust and gasses surrounding the comet itself, at the start of the tail. From a navigational point of view, the goal ...


13

Rosetta collected dust from 67P/Churyumov-Gerasimenko and anylyzed it under an atomic force microscope, without landing on the cometary body itself; depending on your definitions this would seem to imply having flown through its tail. Navigation isn't much of an issue; you simply navigate close to the cometary body and hang out on the sunny side -- though I ...


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