Astronautics
Videos
Page
Astronautics is the practice of sending spacecraft beyond Earth's atmosphere into outer space. Spaceflight is one of its main applications and space science is its overarching field.
Hubble Space Telescope over Earth (during the STS-109 mission)
Outer space
Videos
Page
Outer space is the expanse beyond celestial bodies and their atmospheres. It contains ultra-low levels of particle densities, constituting a near-perfect vacuum of predominantly hydrogen and helium plasma, permeated by electromagnetic radiation, cosmic rays, neutrinos, magnetic fields and dust. The baseline temperature of outer space, as set by the background radiation from the Big Bang, is 2.7 kelvins.
The boundary between space and Earth, at an altitude of 100 km, roughly where the yellow line of airglow is visible.
The black background is outer space as seen from Earth's surface at night. The interplanetary dust cloud is illuminated and visible as zodiacal light, with its parts the false dawn, gegenschein and the rest of its band, which is visually crossed by the Milky Way
Because of the hazards of a vacuum, astronauts must wear a pressurized space suit while outside their spacecraft.
Conventional anti-satellite weapons such as the SM-3 missile remain legal under space law, even though they create hazardous space debris