The first one was 83.6 kg, the heaviest is more than 6500 kg and the lightest are less than 10 kg and are classified as a Nano satellites. The sheer economics of sending a payload into orbit is forcing satellite designers to think small. Israel plans to launch two nano GPS satellites as a proof-of-concept later this year. The SSTL has a proven track record about the design and deployment of small satellites. Students from IIT Kanpur, India are designing a nano sat with imaging capabilities. These satellites will add to the already present man-made material orbiting our planet.

The news about the collision between an Iridium satellite and an expired Russian Cosmos spacecraft on the 10th of this month, made me run a frantic web search for the orbital heights of all the popular imaging satellites we have up there. The closest to the 785 km orbit of the Iridium and the Cosmos is RadarSat-2 at 798 km, albeit in a different plane. What happens to the nearly 300 new detectable fragments from the collision? As these fragments slowly but surely undergo orbital decay, the probability of collisions with other satellites cannot be ruled out. What can result is a chain reaction and if luck runs out we might suddenly be left with a few less imaging satellites and many more fragments...

In a lighter vein- might be the nano satellites are really the hope for the future as the probability of a small object colliding with a smaller object is much lower...