The Argos system on the yacht carried a transmitter that radiated a code signal at 60 second intervals. The satellite Noah 9 carried the receiver for the Argos system and the signal data was downloaded every few orbits to a computer in Virginia, USA. The data was then sent to Toulouse, France, and from France to the Centre for Marine Science & Technology (CMST) in Bentley, WA. The signal was guaranteed accurate to within three kilometres, but was usually more accurate than this, being reliable to within 100 metres. If Sanders had to abandon ship, he could activate the alarm button on the transmitter platform to alert scientists in Toulouse who would in turn notify the French Coast Guard, CMST and the Sea Safety and Surveillance Centre in Canberra. If the transmitter stopped sending the signal, the CMST would also be notified.
At 11.35am on 25 November 1987, the Argos satellite reporting system on the yacht went into distress mode and an alarm was relayed to John Penrose and his assistant, Tim Pauly, at the CMST. At the time, Sanders was off the Falkland Islands. Penrose telephoned the Canberra Sea Safety Centre, Parry Corporation, the Falklands Governor in Port Stanley and the Port Stanley Harbour Master, Captain John Jackson. By 10pm, Penrose was notified that a Royal Navy Sea King Helicopter had made an aerial sighting of Sanders on his yacht and all was well. The false alarm had ceased after 100 minutes and it is still not known what caused the malfunction in the ARGOS system. At 3.15am the next day, the Canberra Centre phoned John Penrose to inform him of another mayday message, calling back some 15 minutes later to report that it was an error. The message was actually from the previous day’s false alarm. (Source Project Endeavour)