Yes & no - depends of course on the hardware you have, and its capability:
You will need:
1) Microwave dish and feed for the right frequencies
2) and of course a receiver capable of not only the freq's, but capable of digital demodulation of the type used and the required selectivety
.. and you are going to have to know where the satellite is
Suggest you start off reading up on satellite comms to get an understanding of the techniques and methodoligies used, and then perhaps kick off monitoring the UHF Inmarsat analogue comms - they are relatively easy to hack into and will give you a grounding and the experiance needed to understand how to go about things (up/downlink channel selection, channel spacing, bandwidths, demodulation requirements ect etc ... ) - but to answer your question: nope, in principal: its not too difficult a task to monitor sat comms
........ and don;t muddle up digital modulation with encyrption (you can always record what you are listening to and then compare it with one of the many online sites that have recordings of analogue and digital modulation samples on them). Forget trying to decrypt - can be done in some cases, but you'll be at it all day for next to no return.
