Retired Nasa satellite to re-enter atmosphere – but risk from debris is ‘low’
A 300kg Nasa satellite will fall to Earth in the next few hours, and while parts are expected to survive the fiery re-entry, experts say the risk of anyone being injured by debris is ‘low’ at 2,467-1.
The satellite, known as Rhessi (Reuven Ramaty High Energy Solar Spectroscopic Imager), was retired in 2018 due to communication problems. Launched on February 5, 2002, it spent 16 years monitoring solar flares, helping scientists understand the underlying physics of how such powerful bursts of energy are created.
Nasa and the Department of Defense have not disclosed where the satellite is expected to re-enter the atmosphere, but estimates it will happen around 9.30pm ET (2.30am BST Wednesday) – plus or minus 16 hours.
A statement from Nasa said the risk of harm coming to anyone on Earth was ‘low’.
‘NASA expects most of the spacecraft to burn up as it travels through the atmosphere, but some components are expected to survive reentry,’ it wrote. ‘The risk of harm coming to anyone on Earth is low – approximately 1 in 2,467.’
The agency continued: ‘The spacecraft launched aboard an Orbital Sciences Corporation Pegasus XL rocket with a mission to image the high-energy electrons that carry a large part of the energy released in solar flares. It achieved this with its sole instrument, an imaging spectrometer, which recorded X-rays and gamma rays from the Sun.
Before Rhessi, no gamma-ray images nor high-energy X-ray images had been taken of solar flares.
‘Data from Rhessi provided vital clues about solar flares and their associated coronal mass ejections. These events release the energy equivalent of billions of megatons of TNT into the solar atmosphere within minutes and can have effects on Earth, including the disruption of electrical systems. Understanding them has proven challenging.
‘During its mission tenure, Rhessi recorded more than 100,000 X-ray events.’
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