The questions that we are trying to answer today are:
What were the first satellites like?
How have satellites changed?
Are all satellites the same?
The first artificial satellite that was ever launched was the Sputnik 1, on 1957. A metallic sphere of 83 kilograms and 58 centimetres of diameter was the first object to be put in orbit, and it changed forever the way we see space. In the following audio it is possible to listen to an audio recording of Sputnik’s radio transmission by NASA.
Sputnik’s signal.
Since that first piece of metal that was launched technology has been greatly improved, satellites are more efficient and are able to accomplish bigger goals. Satellites have also grown in size, the development of propulsion technology and the improvement of structures, materials and hardware has allowed bigger deployments with bigger payloads, bigger solar panels and bigger antennas.
Evolution of Intelsat satellites.
However, with the progress towards bigger satellites there has also been a tendency towards smaller and cheaper satellites. More efficient batteries, materials, the same way Moore’s Law works, have allowed space companies to create smaller and smaller satellites. Which has made possible to launch more satellites together at the same time in the same rocket. All of this has helped in the democratization of space, by making it more accessible and open to bigger audiences.
Satellites of different sizes.
As satellites got smaller new categories of satellites were born depending on their weight. In the following list you can have an idea of the classes in which satellites are divided.
- Mini satellites ~100-500 kg
- Micro satellites ~50-100 kg
- Nano satellites <10 kg
- Pico satellites 0.1-1 kg
Yet this paradox has an explanation, bigger satellites are used for Geosynchronous Earth Orbits, as it takes more resources to put a satellite in such orbits and the longer they can last the less money that must be invested for the next substitute satellite. On the hand, in Low Earth Orbit, as the effects of the atmosphere are greater and the lifetime of satellites is lower, the smaller we make satellites, the less drag forces they produce on orbit and the more efficient they become.
The course of space history was also changed with the introduction of the cubesat in the industry. In 1999 professors Jordi Puig-Suari from California Polytechnic State University and Bob Twiggs from Stanford University proposed the CubeSat reference design. A standardized miniaturized satellite for space research that is made up of multiple 10 cm × 10 cm × 10 cm cubic units with a mass of no more than 1.33 kilograms per unit.
Puig-Suari and Twiggs with a cubesat from NASA.
More recently a new step was made in the path to make space more reachable, it was thanks to Zac Manchester from Stanford University in 2011 with a model of femtosat, the KickSat. Despite being still in the early stages of development and has been launched only twice to space, it could be possible that we could soon acquire one of this tiny satellites for just a few hundred euros/dollars.
KickSat in action, deploying the femtosats from the mothership.
Regarding the actors who execute space missions, there are different interests and motivation for it and different entities that do it.
The first one of them is civil institutions, which are mainly space agencies, rather national, like CNES (France), or international, like ESA (Europe). Their main interests are science, research and the creation of technological infrastructure for the improvement of society, such as Earth observation platforms.
The next kind of body that participates in space are military institutions, which can be again national (U.S. Space Force), or international (NATO). They could have interests such as surveillance of global navigation systems.
Finally, there are commercial corporations, like (Starlink), their motivation is to make a profit and the business could be for example telecommunications.
