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### Where does space begin on planets without atmospheres?

On Earth the Karman Line is used as the boundary of space, and I believe it is defined as the height where you would have to go faster than orbital speed in order to obtain aerodynamic lift. Therefore ...
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### How did the X-15 control attitude above the Kármán line?

This interesting, archived page https://www.webcitation.org/618QHms8h?url=http://www.fai.org/astronautics/100km.asp which I found in this answer, says: In the early 1960´s, the U.S. X-15 Aircraft ...
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### Karman line analog on other celestial bodies

Is there a common definition of where the space begins on other planets (and other celestial bodies)? An equivalent of the Karman line. How far one should go from the martian surface to get to the ...
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### What does it take for a craft to perform a flight simulating weightlessness without having to fly a steep parabola/ellipse?

Alright, I'll try to ask a better question on what I mean so that we figure out how one becomes weightless in a craft without having to fly steep parabolae. Other than flying parabolae or nose-down ...
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### When do aircraft become solarcraft?

Any body travelling through particles undergoes drag. Any body able to generate lift (for instance spheres cannot generate lift) can generate lift if it undergoes drag. First by assuming one body in ...
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### Why does Earth's atmospheric density have a big "knee" around 100 km? Is there a good analytical approximation?

I've used a quick very rough approximation of the drop of atmospheric density with altitude in this answer and in this answer by using a single exponential and scale height parameter, but that's not ...
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### Did the Soviet Union put an unmanned satellite in "very low orbit"above the Kármán line which used aerodynamic attitude control?

This interesting, archived page https://www.webcitation.org/618QHms8h?url=http://www.fai.org/astronautics/100km.asp which I found in this answer, says: Later in the same decade (or very early in ...
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### Did the crew of Soyuz MS-10 pass the Karman Line?

Just wondering if Nick Hague got his gold astronaut wings.
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### Where are the "World's First Space Engines" now?

From the Wikipedia article Pioneer P-30: At an altitude of about 370 km (230 mi), the first stage separated from the second stage. When the second stage was ignited, telemetry showed abnormal burning,...
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### Is it possible to perform powered flight on the upper atmospheres of gas giants?

After reading about Ingenuity, whose main challenge I heard was dealing with the relatively thin atmosphere of Mars, I wondered if the thicker atmospheres of gas giants could allow for powered flight ...
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### Orbital reentry glider with no heat shield

Let's assume a reentry craft designed to not use heat protection like Soyuz or the Space Shuttle, and budget is not an issue. The Concorde max surface temperature was 400 K, so let's use this as a max ...
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### Is the equation showed below the right one for an airplane flying at the Kármán line altitude?

$$\frac{GM_Em}{(R + h)^2} - \frac{ \rho v^2 S C_L}{2} = \frac{mv^2}{R + h}$$ $GM_E$ is Earth's standard gravitational parameter , $R$ is Earth's radius and $h$ the altitude of the airplane above the ...
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### Where does the definition of the Kármán line on Wikipedia come from?

According to Wikipedia's article about the Kármán line: The Kármán line is the altitude where the speed necessary to aerodynamically support the airplane's full weight equals orbital velocity ( ...