Experts say a dead NASA spacecraft will fall to Earth in the coming days. NASA’s RHESSI satellite, which studied the Sun from 2002 until its decommissioning in 2018, re-entered Earth’s atmosphere around 9:30 p.m. ET on Wednesday, April 19 (April 19; 01:30 GMT 20 April), plus -minus 16 hours. expected to enter. , according to the latest estimates of the US military.

RHESSI (short for Reuven Ramaty High Energy Solar Spectroscopic Imager) is not a very large satellite. It weighs just 600 pounds (270 kilograms), and much of that mass would have been reduced to ash and vapor during RHESSI’s deadly dive, NASA officials said. However, “some components are expected to survive reentry,” agency officials said in an update Monday, April 17. “The risk of harming anyone in the world is low – about 1 in 2,467.”

RHESSI’s impending fall is another reminder that Earth orbit is becoming an increasingly crowded and dangerous place. For example, global space surveillance networks are currently tracking more than 30,000 orbital debris. But there are many others that are too small for us to control.

The European Space Agency reports that about 1 million objects with a width of 0.4 to 4 inches (1 to 10 centimeters) are currently orbiting our planet. And the estimated number of parts from 0.04 inches (1 millimeter) to 0.4 inches is really impressive – about 130 million.

Even these tiny bits can cause serious damage if they hit a satellite or crewed spacecraft, given their enormous speed: In low Earth orbit, where the International Space Station and many other spacecraft fly, objects move at around 17,500 mph (28,160 mph). it does. km/h).

And collisions in space produce much more space debris, which can lead to more collisions on the way. If there are enough of these, we will face a terrifying cascade known as the Kessler Syndrome that could severely hamper our ability to explore and use space. The RHESSI satellite entered low Earth orbit in February 2002 aboard a Pegasus XL rocket. The spacecraft studied solar flares and coronal mass ejections with the Imaging Spectrometer, the only science instrument to record X-rays and gamma rays.