By Loren Grush
As aerospace companies vow to fill Earth’s orbit with thousands of new satellites over the next decade, industry experts say it’s time to grade these operators on their efforts to keep space a safe and sustainable place. A rating system could keep companies honest, and ensure that Earth orbit remains open for business and doesn’t become bogged down with excess satellites and debris.
Right now, there are nearly 2,000 operational satellites in orbit, according to the European Space Agency, and agencies are tracking more than 22,000 pieces of debris. But companies like SpaceX, OneWeb, and Amazon have proposed adding giant new constellations of satellites in space, numbering in the hundreds or thousands. As the number of satellites in orbit around Earth grows, the risk of these vehicles colliding will invariably go up, too. Those impacts could create hundreds of pieces of debris that threaten other functioning spacecraft.
“IT’S ACTUALLY ENCOURAGING COMPANIES TO TRY TO BEAT EACH OTHER IN HOW GOOD THEY BEHAVE.”
Satellite operators can take certain measures when building and launching spacecraft that will reduce the likelihood of collisions. Changes to a satellite’s design, position above Earth, or its mission plan can affect its chances of threatening other spacecraft and creating more debris in orbit. Now, two teams of experts, led by MIT and the European Space Agency, plan to put together an independent process that evaluates the decisions that operators make when creating their constellations. The concept, known as the Space Sustainability Rating or the SSR, is meant to provide an extra layer of accountability for companies that send vehicles into space. “It’s actually encouraging companies to try to beat each other in how good they behave, so they can build their brand,” Danielle Wood, an assistant professor of media arts and sciences at MIT and leader of the MIT team, tells The Verge.
There are already regulations in place that are designed to keep Earth orbit clean. Government agencies in the United States that regulate launches, like the FCC, consider how a satellite might affect the space environment before allowing it to fly. And in the 1990s, the US government developed guidelines and best practices for operators to follow that are meant to lower the risk of space debris. The United Nations adopted similar standards to the US, while other countries have developed their own guidelines.
But the World Economic Forum, an international non-profit that aims to improve “the state of the world,” thought there needed to be a parallel system for policing space companies, one that is driven by the industry and requires voluntary action. That prompted the World Economic Forum to select the teams at MIT and ESA to develop the SSR. The teams haven’t come up with specific details for the rating yet, but will spend the next few years figuring out the basics.
One important aspect of the rating will be a company’s adherence to current standards. “Part of the question we’ll ask is: is this operator of a satellite choosing to abide by one of these sets of rules or guidelines?” says Wood. A big part of these standards revolves around the lifetime of a satellite, requiring operators to eventually take their satellites out of orbit. The US calls for satellites to be safely disposed of within 25 years. That either means bringing the satellite close to Earth, where it’s dragged down by gravity and burns up in the atmosphere, or putting the satellite into a “graveyard orbit” — a region of space that no active satellites use.
THE SPACE FOOTPRINT WILL CONSIDER THINGS LIKE A SATELLITE’S ORBIT
The SSR will consider how a company gets rid of its satellites, but it will also consider all of the physical characteristics of a spacecraft that might make the vehicle more dangerous. It’s a concept that Moriba Jah, one of the MIT team’s partners, calls the “space footprint” — similar to the concept of a carbon footprint here on Earth. “It’s the burden that any object — dead or alive — poses on the safety and sustainability of anything else in space,” Jah, a professor of aerospace engineering at the University of Texas who specializes in space tracking, tells The Verge.
The space footprint will consider things like a satellite’s orbit, for instance. “Some orbits are extremely sparse, and there’s nothing else around,” says Jah. “And other orbital regions have many other objects that share that same kind of space highway.” There’s an orbit 22,000 miles above the equator, known as the geostationary belt, that is a very popular place for communications satellites, while orbits between 250 and 500 miles up are also crowded with Earth-observing satellites. A satellite in one of these more crowded orbits will have a bigger footprint than one in a lonelier orbit.
A spacecraft’s maneuverability is also important: does it have thrusters that will let it avoid collisions? And can it move out of the way quickly? The answers to these questions will all factor into the footprint score, says Jah. How a satellite is constructed will also be taken into consideration. If it’s built to withstand extreme temperatures and vibrations, it’ll be less likely to fall apart and create debris. That could mean a lower footprint.
The MIT and ESA teams will need to figure out how much weight to give to each of these satellite characteristics. To get all of the information they need, the teams plan to use publicly available data that companies share on the license applications for their spacecraft. These include the orbits that a satellite is going to, for instance, as well as disposal plans. Wood says the teams might also develop questionnaires that operators can fill out about their spacecraft. “They can choose what to share and what not to share,” she says. “They’ll have to make choice: would I rather get a better rating or hide information, basically.”
Once the rating system is decided, the teams will come up with an algorithm that evaluates how a satellite or constellation might affect other vehicles in space. And it’s possible that when all of this is complete, a new entity, perhaps a non-profit, will be tasked with overseeing those scores. “We’re here to help design the operations and we’ll have to decide through the design process what entity will actually execute it,” says Wood.
“NEAR EARTH SPACE DOES REQUIRE ENVIRONMENTAL PROTECTION.”
Wood sees this tool as a way for companies and operators to enhance their image, by having a good SSR score. It’s also something that could be useful for companies that insure spacecraft, as the SSR could be a good guide for evaluating the liability of a satellite.
But above all, the goal is to come up with another way to keep Earth orbit a functioning place. If too many collisions and debris muck up space, certain orbits could become unusable. And that means we could potentially lose certain capabilities that rely on satellites, from satellite TV and communications to Earth observations and space research. That’s one major reason why Jah and Wood are working on the SSR, as it would provide another way of protecting space as if it were an ecosystem.
“Near-Earth space does require environmental protection,” says Jah. “It’s not necessarily like [the] climate change thing, but it is a global commons, which could suffer a tragedy of the commons if we don’t do something.”