Planetology with small satellites: results and perpectives

Under the common name of small mission actually lies a wide range of satellites from the one unit CubeSat to the S class ESA missions. The history of space exploration did indeed start with satellites that now would be considered small like the Sputnik or the Explorer one. In the years to follow the complexity of the science observations increased with the consequence of a constant growing of the size of the spacecrafts. This situation also lead to the development of larger launchers and costs increase. Consequently, the interest in small satellites, usually defined as those under 500 kilograms up to less than 1 kg, has grown over the years. The miniaturization of once-bulky satellite components, standardization of many satellite parts, and other factors have trimmed costs and realization time substantially.

No doubt that for the human exploration or for deep space exploration missions sizes and masses will continue to be very significative. In contrast, smaller and lighter satellites require smaller and cheaper launch vehicles and can sometimes be launched in multiples. They can also be launched as `piggyback` on mother satellites or planetary carriers.

Even if a quite a large number of small missions have been realized, from the Sputnik times till today a prudent estimate may count almost 900, there are very few examples of planetary missions so far.

In the next future minisats, better known as Cubesats, are under development to be used for planetary sciences as carried as piggy-back of larger missions. Also, small sats with very few instruments on boars, devoted to the measure of specific planetary characteristics will be proposed and likely they will be essential to provide answers to critical observations in a reasonable short time.