Satellites - much smaller than you might think

[AJB Temple]

No. I offspring, in his aspirations to stay at school seemingly forever, is doing a doctorate in space engineering.

Current project has been an eye opener for me. He's working with an agri business to design a tube satellite for them. Each satellite is only about 30cm long, and fits into a small tube. The size is measured bizarrely in litres, and this is a 3 litre satellite. It is propelled into space in a cluster of 25-30 tubes and everything deploys automatically (fold out solar or whatever). They last about 6 years and then burn to dust on re-entry.

It costs around Euros 400,000 to design and make the satellite (in this case it will analyse crop growth and characteristics across vast areas) and 250,000 per tube to launch.

Most large satellites are apparently quite old tech (computer processors from 10-20 years ago, as they must be made to withstand radiation damage. However, these very small ones use current chips similar to phones, as they are in effect “disposable” and are simply replaced every 5 years.

We are being watched by satellites the size of a rolling pin.

 

[Woodster]

It obviously depends on the use. For spying for example:

“Though satellites are often presumed to be small devices floating around in space, the KH-11’s are actually extremely large vehicles. They’re approximately the size of the Hubble Space Telescope, measuring 65 feet long and 10 feet wide, and weighing approximately 40,000 pounds.”

https://www.popularmechanics.com/milita ... atellites/

The article is from 2019 but I expect some are still in use.

 

[StevieB]

Nothing wrong with doing a doctorate, it is getting a job afterwards that is the challenging part :shock:

Payload measured in litres because presumably volume is more important than weight for a space launch?

 

[AJB Temple]

The bit I found interesting is that the larger satellites, orbiting higher, apparently must use much older computer tech because of the need to ensure that they are reliable in a high radiation environment. The costs are also in a different order of magnitude ($15m upwards plus launch).

I suspect that young people qualifying in aeronautical and space engineering are in high demand so getting jobs is easy enough. They get trained to advanced level in material sciences (graphene etc) which has wide application, as well as other things that readily apply across industries.