Space debris concern for mini-sats

Space engineers are expressing concern about the threat posed by small satellites (mini-sats, cubesats) adding to the growing cloud of orbiting space debris around Earth.

Space debris expert warns of increasing small satellite collision risk

More than a third of all CubeSats launched to-date (around 160 between 2003 and 2013) are predicted to remain on-orbit for more than 25 years. Since 2005, CubeSats have been involved in more than 360,000 close approaches of less than 5 km with other orbiting objects.
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Dr Lewis and his team used their Debris Analysis and Monitoring Architecture to the Geosynchronous Environment (DAMAGE) model to simulate three future CubeSat launch traffic scenarios until the year 2043. By comparing these with close approach data from 2005 to 2013, the team found CubeSats are estimated to be involved in millions of close approaches over the next 30 years, with a handful leading to a collision. 

Analysis of the close approaches found that most of the collision risk from CubeSats comes from high-speed encounters with large spacecraft. In addition, many of these encounters were in Sun-synchronous orbits that are popular with remote sensing and Earth science satellites.

Oh Great.  Tell NASA.