The US Federal Aviation Administration (FAA) has proposed new rules to try and limit the proliferation of space junk.
It requires commercial space operators to choose from among five options to dispose of the upper stages of launch vehicles, including
- conducting a controlled re-entry
- moving the upper stage to a ‘graveyard orbit’ that lies away from common operational orbits
- sending the upper stage on an Earth escape orbit
- retrieving the upper stage within five years
- performing an uncontrolled atmospheric disposal.
The last option would give firms 25 years for the upper stage to burn up in the Earth’s atmosphere.
“Given that the entire mission lifetime of upper stages and their components is quite short, and spent upper stages pose a significant risk of debris propagation the longer they are in orbit, it may be appropriate to have a shorter disposal timeline of five years or another time period less than 25 years,” the proposed rule states.
The number of smaller pieces of space debris currently in orbit is thought to number more than 100 million. Due to their colossal orbital speeds, even small pieces can pose a threat to satellites and spacecraft, several of which have been damaged or destroyed already.
Furthermore, the number of satellites in orbit is expected to increase from around 9,000 today to over 60,000 by 2030 – further increasing the possibility of space collisions that will worsen the space debris problem.
There are fears the predicted growth of the industry could make large parts of Earth’s orbit totally unusable.
By strictly limiting the uncontrolled re-entry of upper stages, the FAA said it also wanted to mitigate the risk to people on the ground and in flight due to its significant size and mass and the uncertainty of where it will land.
Last year, scientists calculated that there is a 10 per cent chance that space debris will kill one or more people over the next decade as it falls from the sky.
The proposed rules would align commercial space orbital debris mitigation practices with those accepted by the US government for its space missions.
In March, scientists called for a legally binding treaty to cut the amount of space junk orbiting the Earth, which would include enforcement action taken on satellite sustainability for any nation with plans to use Earth’s orbit.
