How a satellite sees. Earth-observation satellites carry three main kinds of sensor:

How a satellite sees: optical cameras take pictures but need daylight and a clear sky, radar sees through cloud and at night, and hyperspectral sensors read hundreds of narrow bands of colour.

Where they fly. Most of these satellites are in low Earth orbit, a few hundred kilometres up. That is many times higher than a passenger plane, which cruises at about 11 kilometres. A satellite at this height goes round the Earth in about 90 minutes. To see the same place often, companies fly many satellites together, called a constellation.

Where they fly: Earth-observation satellites circle in low Earth orbit, a few hundred kilometres up, many times higher than a passenger plane, and companies fly many together as a constellation.

Why start-ups can now do it. Satellites have become small and cheap. Some are the size of a suitcase. They can share a rocket with other satellites, which cuts the cost of launch. In 2020, India opened its space sector to private companies. It set up IN-SPACe, a government body that authorises and supports them.

How the money flows. Satellite companies sell images, sold by the area covered. They also sell analysis: not the picture, but the answer, such as which fields are under stress. The buyers are governments and armed forces, farming and insurance companies, mining companies, and those who watch shipping. (More on how satellite images are used for farm loans and crop insurance in Market Segment 45.1, Satellite crop monitoring, in Industry Vertical 45, Agritech.)

Tracking what is in orbit. Thousands of satellites now circle the Earth, along with many pieces of debris, such as old rocket parts. A collision can destroy a satellite. So satellite operators need to know where everything in orbit is, and when to move out of the way.

A small group of start-ups in Bengaluru now builds imaging satellites and the software that tracks objects in orbit.

Every company named here has posted software engineering jobs in India. Famous companies that don't actively hire software engineers in India are left out.