Research

MIT and ESA have proposed creating a satellite safety rating

As aerospace companies promiseto flood the Earth’s orbit with thousands of new satellites over the next decade, industry experts say it’s time to classify these operators according to their desire to keep space safe and clean. The rating system will help companies to remain honest and ensure that the Earth’s orbit is open to business and free from unnecessary debris, debris and satellites.

It's time to fight debris in orbit

Currently, according to the Europeanthe space agency has about 2,000 active satellites in orbit, and the agencies are tracking more than 22,000 debris. But companies such as SpaceX, OneWeb, and Amazon have proposed adding giant new satellite constellations in the hundreds or thousands. As the number of satellites in Earth orbit increases, the risk of collision of these vehicles increases. Collisions can create hundreds of fragments that threaten other functioning devices.

Satellite operators can accept certainmeasures in the creation and launch of a spacecraft aimed at reducing the likelihood of a collision. Changes in the design of the satellite, its position above the Earth or in terms of its flight may affect its chances of threatening other spacecraft and creating excess debris in orbit.

Space Sustainability Rating

And so, two groups of experts from MIT and ESAplan to create an independent process for evaluating decisions made by satellite operators when creating their constellations. The concept of Space Sustainability Rating (SSR, "space stability rating") should provide an additional level of responsibility for companies that send vehicles into space. “This essentially encourages companies to compete with each other for good behavior, for building reputation,” says Daniel Wood, associate professor of media art and science at MIT and head of the MIT team.

Already there are regulations intendedto maintain the purity of the Earth’s orbit. Government agencies in the US that regulate launches, such as the FCC, are considering how a satellite can affect the space environment before allowing it to fly. In the 1990s, the US government developed guidelines and methods for operators to follow to reduce the risk of space debris. The UN adopted standards similar to those of the United States, while other countries developed their own guidelines.

But at the World Economic Forumsuggested that there should be some kind of parallel system for controlling the space companies, managing the industry and requiring voluntary action. Therefore, MIT and ESA were chosen to develop SSR. The teams have not yet decided on the details of the rating, but will spend the next few years learning the basics.

One of the most important aspects of the rating will bethe company's compliance with current standards. “One of the questions we’ll ask is this: does this satellite operator comply with certain rules and guidelines?” Says Wood. Most of these standards revolve around the life of the satellite, requiring operators to eventually bring their satellites out of orbit. The US requires the safe disposal of satellites after 25 years. This means either the satellite is approaching the Earth, where it is attracted by gravity and burns in the atmosphere, or the satellite is put into an “orbit-cemetery” - an area of ​​space that no active satellite uses.

SSR will consider how a company disposesfrom their satellites, as well as take into account all the physical characteristics of the spacecraft, which can make the vehicle more dangerous. This is a concept that Moriba Jha, one of the partners of the MIT team, calls the “space footprint” - similar to the carbon footprint concept on Earth. “This is the burden that any object, living or dead, places on the safety and stability of everything else in space,” says Jha.

The space trace will take into account, for example,satellite orbit. “Some orbits are extremely empty, there’s nothing in the area,” says Jha. "Some contain many other objects in the same space highway." There is an orbit of 40,000 kilometers above the equator - the geostationary belt is a very popular place for communications satellites; and orbits at an altitude of 400-900 kilometers are also crowded with Earth observation satellites. A satellite in one of these relatively crowded orbits will have a larger footprint than a satellite in a relatively empty orbit.

The maneuverability of the spacecraft is also important: Does he have engines that will avoid collisions? Can he quickly get out of the way? According to Jah, the answers to these questions will be taken into account when calculating the area. As the satellite is built, this will also be taken into account. If it is designed to withstand extreme temperatures and vibrations, it is less likely to fall apart and turn into garbage.

MIT and ESA teams will have to figure out how much weightgive each of these satellite characteristics. To get all the necessary information, the teams plan to use publicly available data that companies exchange in licensing bids for their devices. These include, for example, satellite orbits, as well as disposal plans. Wood says that operators will have to choose between the best rating and the ability to hide some of the information.

As soon as the rating system is adopted, the teamswill propose an algorithm estimating how a satellite or a constellation can affect other vehicles in space. It is possible that when this is completed, it will be the responsibility of another organization to monitor these indicators.

Companies and operators will be able to improve their image,boosting your SSR. It will also be useful for companies that insure their ships - SSR can be a good guide for assessing satellite liability.

But the main goal is to keepEarth orbit in working condition. If there is too much debris in space, some orbits may become unusable. So, in theory, we can lose certain capabilities that depend on satellites, such as satellite television and communications, Earth observations and space research. This is one of the main reasons Ja and Wood are working on SSR — it provides another way to protect space.

"Near-Earth space requires protectionenvironment, ”says Jha. “It’s not as big a problem as climate change, but a global treasure that can suffer from tragedy if we don’t do anything.”

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