Question: What kind of things could these small spacecraft do?

Charlie Ryan answered on 14 Mar 2011:

That is a very good question – and i think you have cottoned on to a problem with them that is well known in the field – they are so small that they can only hold a limited number of instruments. Quite obvious really! Currently they are mostly doing basic earth observation (but still very useful – there was one called Quakesat that monitored earthquakes) and many physics experiments (like space weather testing).
But they are limited, especially so as there is not a propulsion system that will fit on them – that’s where our mini rockets come in!