International Space Station (Courtesy of NASA)
It may surprise the reader but today there are over 8,000 satellites orbiting the Earth of which just under 50% are no longer active. What is more surprising is that the number of satellites may rise to 40,000 in the next few years.
What do satellites do? A multitude of tasks including spying, providing communications including the internet, mapping the world and weather forecasting.
Why is there such an increase? Private companies are finding the cost of developing and manufacturing satellites within their financial reach.
What happens to a satellite when it’s life expires? Sadly, there is no internationally agreed plan of retrieving obsolete satellites, so they continue orbiting the Earth. However; Amazon one of the companies involved has disclosed plans to de-orbit their satellites within 355 days following mission completion. Should other countries and companies, follow suit then this will help relieve a potentially dangerous situation
How much debris is orbiting our Earth? The figures are mind boggling, there are presently an estimated 128 million pieces of debris orbiting the Earth. Of these around 34,000 are over 4 inches in size (figures obtained from the Natural History Museum in London). Space debris can be caused by prolonged exposure to intense ultra violet radiation as well as the collisions of satellites. In June 2021 the International Space Station was struck by a piece of debris that punctured a hold in a robotic arm, fortunately none of the astronauts were harmed.
Of course, the main concern for those of us on Earth is that of a spent satellite re-entering the Earth’s atmosphere and crashing on a populated area even though they are designed to break up on re-entry.
What of the future?
The launch of ELSA-d is a small but significant step in cleaning up space debris. Let us hope it is not too little too late.
For further information:
https://astroscale.com/astroscale-celebrates-successful-launch-of-elsa-d/
https://www.space.com/how-many-satellites-are-orbiting-earth
https://www.livescience.com/how-many-satellites-orbit-earth#:
Spring Equinox: Sunday 20th March at 15.33 hours
Meteorite Showers: Lyrid Meteor Showers peak on the 22nd April.
Mercury Not observable until 29th April in the early evening sky.
Venus Visibility declines in early mornings of March, but can still be observed towards the south east horizon throughout April.
Mars Not the clearest planet to be seen but can be identified to the right of the brighter Venus during the early mornings of March and April.
Jupiter Not observable during March but towards the end of April will be seen close to Venus in the early mornings.
Saturn Starts to emerge in the pre-dawn sky towards the end of March forming a small triangle along with Venus and Mars. Throughout April it continues to climb higher by the time sunrise arrives.
John Harris