Dead satellites and rocket bodies that linger in low Earth orbit can present risks of collision to active satellites.
As the ship flies around a planet to use gravity as an aid, something goes awry, deviating from its intended path and striking instead a collision course with that planet – not ideal.
Mechanics
NASA engineers dedicate considerable resources and energy to ensure spacecraft are resilient enough to withstand the harsh environment of outer space, but sometimes that isn’t enough. A leak, collision, sensor malfunction or wear and tear may wreak havoc inside an otherwise functional machine and send its contents flying free into outer space, altering its trajectory or leading to its total demise.
Breaking free from Earth’s gravitational pull requires immense amounts of energy, which explains why so many satellites and machines end up in orbital graveyards above our planet, destroyed by either being burned up by the Sun or falling back into Earth’s atmosphere. Even to leave orbit and enter solar space requires even greater power, and violating treaties against this activity is considered highly illegal.
On occasion, a ship’s crew may choose to purposefully crash-land on a planet for experimental reasons. Such decisions can be extremely risky and may prove fatal; but such ventures could also yield new information about the destination planet and open doors to future missions.
Damage
Spaceflight presents unique risks. From its first lunar landing in 1959 to recent incidents involving SpaceX Falcon 9 rockets at Cape Canaveral and other locations, human space travel has seen many accidents and crashes over its history.
SpaceX’s Falcon 9 rocket explosion produced a range of debris, from broken windows in Port Isabel homes to plastic and metal fragments and clouds of dust and sand-like particles that may pose health hazards to people with asthma. All this debris created a public health emergency for some who live nearby and presents risks to others who live near by.
Liability Convention requires States to compensate private individuals and legal entities harmed by spacecraft damage; however, this only applies when launching State has direct interests in the claim (Article VIII). This note discusses the difficulty associated with identifying responsible States as well as why current liability law fails to adequately address this matter.
Environment
Many materials used in spacecraft construction are extremely toxic, and their breakup upon reentry could release dangerous chemicals into Earth’s environment. Hydrazine rocket fuel, for instance, poses a severe threat to life on our planet if it comes into contact with ocean waters.
Engineers devote much time and energy to designing machines that can withstand the hazards of spaceflight, including crashes into planets or asteroids that could provide useful data that would help scientists create more successful missions in future missions.
As companies and governments follow IADC guidelines more strictly, the less likely a spacecraft accident will result in either the loss of an essential satellite or astronaut death. One step towards reaching this goal is clearing away larger debris objects from orbital highways before they become hazardous fragments that threaten spacecraft even decades later.
Survival
Spacecraft engineers spend much time and effort designing their machines so they are resilient enough to withstand the stresses associated with launch, travel and reentry/landing. Unfortunately, even well-constructed machines may contain small imperfections which could have disastrous results.
As one example, while Ryan Stone was floating through space aboard the Space Shuttle that brought her to Hubble Space Telescope, an item from its path struck her helmet, resulting in a 1-inch cut requiring stitches.
Most objects re-entering Earth usually disintegrate completely during their re-entry as Earth’s dense atmosphere quickly converts their orbital energy into heat, but occasionally larger spacecraft or rocket parts composed of high melting-point materials may survive and reach the ground or ocean surface, known as cosmic bullets.