They feel heavy. Their vestibular system is still recovering, so their balance is off. They often feel like they are spinning. Moving their head too quickly can be disconcerting and painful.

Weightlessness causes several key systems of the body to relax, as it is no longer fighting the pull of gravity. Astronauts’ sense of up and down gets confused, NASA said, because the vestibular system no longer can figure out where the ground and the ceiling are.

The astronauts, the ISS itself and other objects in Earth orbit aren’t floating, they are actually falling. So, as they accelerate towards the Earth, the Earth curves away beneath them and they never get any closer. Since the astronauts have the same acceleration as the space station, they feel weightless.

In the absence of gravity there is no weight load on the back and leg muscles, so they begin to weaken and shrink. In some muscles degeneration is rapid, and without regular exercise astronauts may lose up to 20 percent of their muscle mass within 5-11 days.

In space, of course, you can’t have any fires because there isn’t any oxidizer (i.e. oxygen) to sustain the combustion process. In space, of course, you can’t have any fires because there isn’t any oxidizer (i.e. oxygen) to sustain the combustion process.

Fires can’t burn in the oxygen-free vacuum of space, but guns can shoot. Modern ammunition contains its own oxidizer, a chemical that will trigger the explosion of gunpowder, and thus the firing of a bullet, wherever you are in the universe.

Smoke from your cigarette rises because the particles that make up the smoke are driven upwards by the rising of the hot air from the flame. In space hot air doesn’t rise up because there is no ‘up’. Smoke rises because it’s hotter, therefore lighter, than surrounding air. It won’t rise in a weightless environment.

Yes, provided there is an oxidizer. A spaceship with liquid hydrogen and liquid oxygen will blow up quite well in the vacuum of space. Chemical explosives will also explode in space since they function by breaking weakly bonded chemical components; no oxygen is necessary.

There is no atmosphere to transmit sound in space, so no. Sound needs a medium to travel (such as air), but space generally doesn’t have it. Therefore, sound can’t really propagate in space. So you can’t hear an explosion or any other sound in space.

GRB 080916C is a gamma-ray burst (GRB) that was recorded on September 16, 2008 in the Carina constellation and detected by NASA’s Fermi Gamma-ray Space Telescope. It is the most powerful gamma-ray burst ever recorded.

Missile defense does not station weapons in space, but is designed to intercept incoming warheads at a very high altitude, which requires the interceptor to travel into space to achieve the intercept.

One key realm in which the ODNI has identified China to have an especially aggressive hold is its ASAT (anti-satellite) weapons, which China has prepared its militaries to use to destroy U.S. satellites. The threat of these space weapons has grown in recent years.

Orbital weaponry As of September 2017, there are no known operative orbital weapons systems, but several nations have deployed orbital surveillance networks to observe other nations or armed forces. Several orbital weaponry systems were designed by the United States and the Soviet Union during the Cold War.

Weapons are very dangerous objects to keep on the ISS, so the American astronauts do not bring guns for safety reasons. There is, however, a gun located in the Russian return capsule, should the need arise to use it upon an emergency return against wildlife back on Earth.

In 1975, the Soviet Union did something that had never been done in space before. They fired a gun from a space station, the one and only time such a thing has happened. It was an event that was only uncovered after the fall of the USSR in the early 1990s.