Vital services including internet access, weather forecasts and navigation could be put at risk by increasing greenhouse gas emissions, as well as growing space debris, a report has found.

The warning came in a study published by the Massachusetts Institute of Technology on Tuesday, which found low-earth orbit satellite numbers would need to be cut by as much as 66 per cent under a high-emissions scenario.

Australian aerospace experts warned the problem could hit households in rural and remote areas of the nation hardest, and called for worldwide regulations to prevent the cutbacks.

The report also comes as the number of satellites launched around the world grows, with low-earth orbit satellite numbers expected to reach 100,000 within five years.

The study, led by MIT’s Dr William Parker and published in the journal Nature Sustainability, investigated the future of low-earth orbit satellites and modelled the impact of three carbon emission scenarios on the technology.

Previous research found greenhouse gas emissions shrank the upper atmosphere in which satellites could be used, and increased the time space debris remained in orbit.

This study found the number of low-earth orbit satellites that could safely operate would be reduced by 50 to 66 per cent by the end of the century under a high-emissions scenario, depending on solar activity.

“If no governance action is taken to manage the occupation of earth’s orbit, the environment will very likely become over-utilised, diminishing the orbital resource and limiting future access,” the report said.

“Reasonable constraints include (satellite) launch limitations, spectrum allocation, limited capabilities in tracking and conjunction assessment, operational requirements and dynamical stability.”

Low-earth orbit satellites are used to deliver critical services including weather forecasts, environmental monitoring, high-speed internet, and navigation.

But the number of satellites has risen exponentially in recent years, Swinburne University of Technology astrophysicist Sarah Webb said, with almost 10,000 satellites expected to be in orbit by the end of the year and 100,000 by 2030.

Dr Webb said commercial aerospace firms including Elon Musk’s SpaceX had made it easier to launch satellites, as well as launching large constellations of their own satellites to provide Starlink broadband services.

“A pragmatic view is that we do need satellites in space to be able to have internet access in remote and rural communities – that’s really important and it’s something that we can’t say we’re not going to support – but we also don’t need it to be ridiculously crowded with a high amount of assets up there,” she told AAP.

“Not only are we launching more satellites, but the debris problem is going to get out of hand.”

In addition to reducing carbon emissions, Dr Webb said space agencies and regulators from around the world needed to develop uniform space debris policies, which included an end-of-life strategy for satellites so they did not become hazardous.

“This is a global citizen problem where every nation needs to work together to determine what is the best path forward,” she said.

“We have to have a debris-mitigation strategy in place.”

Jennifer Dudley-Nicholson
(Australian Associated Press)