‘Apophis’ asteroid could take out satellites in...

‘Apophis’ asteroid could take out satellites in 2029.

The European Space Agency had updated it’s predictions for the trajectory of asteroid 99942 ‘Apophis’, based on new data gathered as it passed about 14.5 million from Earth last weekend.

The new data shows the asteroid is bigger than previously thought. “The 20% increase in diameter, from 270 to 325m, translates into a 75% increase in our estimates of the asteroid’s volume or mass,” says Thomas Müller of the Max Planck Institute for Extraterrestrial Physics in Garching, Germany, who is leading the analysis of the new data. The team also gathered new data on the albedo (a measure of reflectivity) of Apophis, which is important for trajectory modelling, given that heating from the Sun can influence it’s path.

The updated model shows Apophis will pass within 36,000km of Earth’s surface - well within the orbit of some satellites. That distance just happens to be the lower limit of geostationary satellite orbits, which are most often used for communication and broadcast, as well as weather and classified military satellites. Although there’s currently around 400 currently outside this geosynchronous orbit, there are even more at the most used altitude of around 20,200km. If future updates on the trajectory show it coming that close there’s a chance it could take out navigation and communication satellites in Medium Earth Orbit, such as GPS and Glonass.

Apophis will pass Earth yet again in 2036, but that orbit is unlikely to be fully understood until after the 2029 pass with Earth, which will change the trajectory of the asteroid.

esa.int