World-wide watch
Flipside’s latest issue reveals the single most detailed portrait of Earth’s surface ever made. It was created by Europe’s giant-sized Envisat satellite. Here are ten further facts about our continent’s leading eye in the sky…
1.Size is everything
Envisat is about the size of a lorry and it weighed in at more than 8 tonnes at launch in 2002, making it the single largest satellite ever flown by Europe.
2. Fully equipped
The satellite carries a total of ten different instruments, to look back on the Earth’s surface in many different ways.
3. Seeing in the dark
As well as observing in visible light, Envisat operates in radar vision allowing it to see through clouds and darkness.
4. Fast mover
It orbits at a height of 800 km, moving around the planet at a speed of 7 km/s, much faster than a speeding bullet, orbiting the Earth every 100 minutes.
 5. Pole position
Like most Earth observing satellites, Envisat orbits from pole to pole rather than around the equator like manned spacecraft. This enables it to cover the entire planet because the Earth is rotating beneath it.
6. Made in Britain
The spacecraft cost a billion pounds and took a decade to construct. Parts came from all over Europe, but key elements including its solar panels were built in the UK.
7. All in a day’s work
Every day it returns sufficient data back down to the Earth to fill a standard PC. Its results are employed in a large number of ways – to check on the ozone layer, respond to disasters such as floods or forest fires, take the temperature of the ocean, even to help predict the path of hurricanes. Inuit even use Envisat to check on the stability of ice they plan to hunt on!
8. Violent neighbourhood
When the Chinese blew up one of their old weather satellites with a missile in January 2007, it created a vast cloud of hundreds of pieces of space debris, some of which have since drifted into Envisat’s orbit. No collision has occurred – yet!
9. Seeing the Earth move
By combining together separate Envisat radar images, scientists can spot ground movements occurring slower than the rate your fingernails grow, helping to identify tectonic faults and areas in danger of subsidence.
10. What’s in a name?
Envisat’s name is the least impressive thing about it – it is short for 'Environmental Satellite'.
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