Uncontrolled rockets pose unnecessary risk, study finds

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There is a chance that one person will be killed by a rocket in the world. If current practices in the space industry stay the same, there will be about a 10% chance over the next 10 years.

The threat in some parts of the world is much larger than in others. Many countries in the Global South are likely to deal with a larger share of space trash even though they are not responsible for it. As more and more satellites are launched into space, it could become a bigger problem.

Michael Byers is the lead author of the analysis and a professor at the University of British Columbia. Is it a good idea to eliminate casualty risks? He thinks the answer should be yes.

As rockets propel themselves into space, they usually drop dead weight because of the empty fuel tanks and engines that are no longer useful. It helps that oceans cover most of the Earth's surface, and some rockets can aim for the ocean with a bit of accuracy.

It is possible to guide equipment back down to Earth safely if a rocket has already made it into space. The company has become famous for landing parts of its rocket so that they can be used again, and it also performs controlled deorbits of the parts it can't save.

The focus of this new paper is the abandonment of some rocket stages after they are launched.

There have been no documented deaths from a rocket reentering the atmosphere. In 2020 a 12-meter-long pipe and other debris from China's Long March 5B rocket crash landed into two villages.

The Chinese rocket stage that fell back down to Earth last year was 100 feet tall. After frightening cities like New York and Madrid, it dropped down in the Indian Ocean. The spark for the research was provided by his son, an undergraduate at the University of Victoria, who is one of the authors on the paper.

Byers and his colleagues found that Jakarta, Indonesia, Mexico City, Mexico, and Lagos, Nigeria are more likely to see a rocket reenter the atmosphere than Washington, DC and New York City.

If you live in a densely populated city at 30 degrees north latitude, then it should be of more concern to you. In order for a satellite to match the Earth's rotation it needs to follow the Earth's equator. The population density at that latitude increases the risk by 30 degrees.

The risk can be eliminated if governments mandate changes and the space industry is willing to pay for them. The 1987 Montreal Protocol that phased out the use of ozone-depleting substances in air conditioners and refrigerators is an example of an international agreement. There is enough fuel left to guide a discarded rocket stage back down to earth. Industry is already adapting.

Current common practice is to say that it is too bad. We will leave the rocket stage in the middle of the ocean and have it return to normal. Jonathan McDowell is an astronomer at Harvard. The Space Force now requires deorbiting of rocket stages. The next- generation rocket is being designed by the company.

The practice is to maximize safety. We think that the same approach should be taken to space launches. Byers believes there is more that can be done to make spaceflight as safe as possible.