A solution seems to be approaching for the enigmatic communication problem that has been preventing NASA's Voyager 1 probe from sending intelligible data from interstellar space since last November.
After receiving a 'feedback' from the control center, on March 3 the probe sent a different signal than usual which contains a reading of the entire memory of the faulty on-board computer.
NASA technicians are analyzing it to try to find the origin of the problem and a way to solve it, as the space agency itself explains on the mission blog.
All attention is focused on one of the three on-board computers, the Flight Data Subsystem (Fds), which serves to package the scientific and engineering data to be sent to the ground through the telemetry modulation unit.
It was precisely from a section of this computer that a signal different from the usual flow of incomprehensible data arrived on March 3rd.
The signal was not in the format used by Voyager 1 when the FDS functions properly, but a Deep Space Network engineer was able to decode it anyway, discovering that it contains a readout of the entire FDS memory.
Inside there is code (i.e. instructions for the tasks to be performed) and variables, i.e. values that can change based on commands or the state of the spacecraft, together with scientific and engineering data for the downlink.
The team is already comparing this reading with the one received before the problem occurred, to identify any discrepancies that could reveal the cause.
The signal was obtained in response to a command that the control center had sent to the probe on March 1, with the aim of inducing the FDS computer to try different sequences of its software package in an attempt to bypass the corrupted section.
Because Voyager 1 is more than 15 billion miles from Earth, it took 22.5 hours for the radio signal to reach the probe and another 22.5 hours for the probe's response to be picked up by antennas on the ground.
Reception occurred on March 3: on March 7 the engineers began to decode the signal and only on March 10 were they able to decipher its content.
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