'no main manifest'

I downloaded Orekit 10.1. I tried executing the JAR in Windows 10, and it did not do anything. I tried to execute it in Linux, and was told that there is ‘no main manifest’. I successfully built Orekit 10.1 in Linux, but have the same error.

Did I do something wrong with trying to run Orekit 10.1?

Hi @pbhuter and welcome.

Orekit is a library, not an application. It has no main method by itself, hence the error message.
Applications are built by users on top of Orekit, and users write their own main method.
There are tutorials that are now published separately from the library itself, see the orekit tutorials gitlab project. Note that the project gathers several tutorials at once, each one with its own main method, so here again you cannot just create a single jar from the project and run it, because we did not set up a manifest with one of the tutorials arbitrarily selected. You could do that if you wish. People usually set up the tutorials project in their IDE of choice and run manually the tutorial they want from the IDE.

Another thing that you may try if you want to get an idea of Orekit capabilities is to check the Orekit as a Service web site. There are several service demos their that you can run online, including measurements generation and orbit determination.