NASA's defunct satellite to fall to Earth this week: Is it dangerous?

The defunct RHESSI satellite, which belongs to NASA and was used to study the Sun, will fall to Earth in the coming days. The device does not pose any threat and the chances of causing harm on Earth are very small.

RHESSI, which weighs just over 270 kg, should enter Earth's atmosphere on Wednesday, April 19, around 05:30 Yerevan time, possibly a little earlier or later.

According to NASA, RHESSI is a relatively small satellite and most of it will literally burn up and disappear in the atmosphere on the way to Earth. However, parts of it are expected to reach Earth, although the risk of harming anyone is very low, at 1 in 2,467.

RHESSI was launched into low Earth orbit on a Pegasus XL rocket in February 2002. The device helped study solar flares and coronal mass ejections using a spectrometer sensitive to X-rays and gamma rays. During the mission, more than 100,000 events in the X-ray range were recorded, which helped to better understand the phenomena taking place on the Sun. RHESSI was decommissioned in 2018.

There is a huge volume of potentially dangerous space debris in the near-Earth orbit. The European Space Agency estimates that there are about 36,500 pieces of space objects larger than 10 centimeters in size, about one million fragments that are 1-10 cm in size, and 130 million fragments that are smaller than 1 cm in near-Earth orbit.

In addition, collisions with larger objects continue to produce especially small fragments that form debris clouds. And while fragments of 10 cm size are regularly monitored, the trajectories of smaller fragments are generally unknown.

The only problem caused by space debris is not that it can reach the Earth. They create obstacles, and will create more in the future, for operating artificial satellites and spaceships.

Recently, researchers of the Byurakan observatory have restored 700 orbits for artificial satellites through monitoring, thanks to which these satellites can avoid a catastrophic collision with space debris.