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2

An example of this are the lunar probes of the Apollo missions. One probe orbited extremely close to the surface before its crash. See(https://jacanswers.com/how-low-have-satellites-orbited-the-moon/)


13

An example of a planetary mass object or planemo that is almost airless is the Moon. It does have an atmosphere, but very, very thin. The Moon has an atmosphere so tenuous as to be nearly vacuum, with a total mass of less than 10 tonnes (9.8 long tons; 11 short tons).[141] The surface pressure of this small mass is around 3 × 10−15 atm (0.3 nPa); it varies ...


38

Yes, but. Firstly the 400km orbits of the ISS are already extremely low, in comparison to the 6400km radius of the Earth. See https://what-if.xkcd.com/58/ for pictures of orbits. So if you rephrase in terms of orbital radii it becomes "We can orbit at 6800km. Can we orbit at 6401.75km?" And the answer is certainly "yes" However take ...


4

Existence of an atmosphere simply means you'd need to supply boost power to maintain orbital speed. Maybe a lot more than, say, the ISS generates to maintain its position :-) . As the comments point out, nonuniformity of surface and/or gravitational field (perhaps due to density variations in the planet's crust, e.g.) mean there's a minimum altitude ...


0

Short Answer: The question and answers seem to ignore one important factor in the ability of planets and other worlds to retain atmosphere. Escape velocity. The escape velocity of a world depends on the mass, radius, and average density of that. At the present time a minimum mass of 0.12 Earth mass seems to be considered necessary, but not sufficient, for a ...


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