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Following on from a previous post regarding the descent of the Upper Atmosphere Research Satellite (UARS), it would appear that the bus sized piece of space junk safely re-entered the Earth’s atmosphere early on Saturday morning 24th September 2011.

By a stroke of luck the vessel plunged to earth somewhere over the southern Pacific Ocean about as far from large land masses as you can get, reducing any possibilities of damage or injury being caused by the 26 parts that would survive the fiery heat of re-entry.

After the launch of this satellite in 1991, NASA and other space agencies agreed to adopt new procedures in an effort to reduce space junk and lessen the possibilities of future satellites causing problems when falling back to Earth.

However, in the immediate future the German satellite ROSAT, launched in 1990 and weighing in at 2.5 tonnes is expected to fall back to Earth in late October or early November this year. Some 30 pieces of debris are expected to survive re-entry, potentially including sharp mirror shards, so we should all continue to keep looking warily to the skies for now! 

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A redundant six-tonne NASA satellite is expected to re-enter the Earth’s atmosphere with the next few hours, potentially scattering debris over a 500km wide area of the planet’s surface.

Whilst the majority of the bus sized Upper Atmosphere Research Satellite (UARS) will burn up upon re-entry into our atmosphere, NASA has indicated that about 26 parts will survive the intense heat and will fall to Earth: including 4 titanium fuel tanks, 3 batteries, 4 steel flywheel rims and an aluminium structure that on its own will weigh 158kg.

Although NASA is tracking the orbit of the falling satellite, the final destination of these objects won’t be known until minutes beforehand due to continuous changes in the atmosphere caused by the Sun.

Target zone is anywhere between 57 degrees latitude north and 57 degrees latitude south, i.e if you live further north than Quebec or further south than Argentina you should not be at risk.

Though you may cast an occasional look to the skies over the next day, I wouldn’t worry too much as you would have to be incredibly unlucky to be struck by some of the falling debris. NASA calculates that there is a 1 in 3,200 chance that a piece will hit a person somewhere on the planet, whilst you own personal risk of you specifically being struck is 1 in 21 trillion – you are far more likely to win this week’s lottery!

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Earth's gravitational pull measured by the GOCE satellite
New images were revealed yesterday in Munich Germany, of planet Earth looking a bit like a multi-coloured revolving potato!

The images, better known as geoid maps, are compiled from data collected by the European Space Agency sponsored Gravity Field and Steady-State Ocean Circulation Explorer – GOCE for short, which was launched in 2009. This satellite flies at an unusually low altitude of just 254km, in a pole to pole orbit, and can measure even the tiniest changes in gravity.

The images show a map of the changes in gravitational pull over the Earth’s surface from the top of mountain ranges down to the depths of the ocean floor.  The bright yellow areas show where gravity is at its strongest and range down to the blue areas where it is at its weakest.

Scientists involved in the project say that although the movements of tectonic plates can not be observed from Space, the patterns of gravity data may assist in understanding the processes involved in natural disasters such as this year’s Japan earthquake, and ultimately enable a better prediction of such events. 

Click the play button below to see the all round view.

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SBSS Satellite
The launch of a new satellite to track space debris was delayed again last week due to continuing software problems. The $500 million Space Based Space Surveillance satellite (SBSS) to be launched by the US airforce,  is set to continually monitor the ‘traffic’ –i.e satellites and rubbish, around the Earth, something that is currently done via ground based radar which can only be used on clear nights.

It is estimated that there are at the moment about 1,000 working satellites and about 20,000 pieces of debris orbiting the Earth, including such things as nuts and bolts, jettisoned spacecraft parts, tools lost on spacewalks and solid fuel fragments. Mankind seems to leave litter where ever he goes!

Although most of the debris in space is relatively small, the danger lies in the fact that it is travelling fast. Below altitudes of 2,000 km, the average relative impact speed is 36,000kmph or 21,600 mph, and so at this velocity any collision can be dangerous. For example, it is calculated that a 1mm metal chip could do as much damage as a .22 calibre bullet, whereas a piece the size of a tennis ball could be as effective as using dynamite – perhaps penetrating and seriously damaging any spacecraft.

All being well, a revised launch date should be set in about a month’s time after further testing of the software has taken place, and the new SBSS satellite will then take its place 627kms above the earth to begin its litter patrol.
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Nasa
Released by NASA this week were some of the first pictures to be taken by the Solar Dynamics Observatory (SDO).

This hefty satellite weighing in at 3 ton was launched in Florida 10 weeks ago as part of a 5 year plan to develop a better scientific understanding of the Sun and its influence on the Earth.

The magnificent images show never before seen detail of extreme close-ups of the surface and material flying out from sunspots, and has also made the first high resolution measurements of solar flares in a broad range of extreme ultraviolet wavelengths.
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Nasa
The imaging assembly contains four telescopes designed to be sensitive at different temperatures which will give scientists more information about how heat is transferred across the sun. Another piece of equipment, called the Helioseismic & Magnetic Imager will look into the interior of the sun to track solar storms from their beginning deep inside to the violent eruptions that take place on the surface.

If you want to see more images then take a look at the film clip below for some impressive shots.
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ESA Cryosat-2
8th April 2010 saw the successful launch in Kazakhstan of the European Space Agency (ESA) sponsored CryoSat-2 satellite.

The original launch of the first version of the £100 million satellite ended in disaster, back in 2005 when the Russian launch rocket carrying it failed, and plunged into the Arctic Ocean.

CryoSat-2 will now sit in its polar orbit and send back data about how the ice caps are reacting to global change. The melting ice of the polar regions is considered a matter of great environmental concern, with future implications for ocean currents, sea levels, and the entire global climate.

This satellite is part of ESA's 'Living Planet Programme' which focuses attention not outwards to Space itself, but, instead seeks to look inwards to see what impact and effects human activity is having on natural planet Earth processes. 
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