Researchers at the Ruhr University Bochum have broken the encryption of the two main standards used to protect calls from satellite phones. The attacks on the GMR-1 and GMr-2 standards are thought to be the first such work against the satellite phone ciphers. Although they were able to intercept the downlink from a satellite to the ground station, they could not actually reproduce the conversation. The researchers recommend that users should think twice before using satellite phones for private conversations.
Source: https://threatpost.com/researchers-crack-satellite-phone-ciphers-020812/76185/