NASA's 47-year-old Voyager 1 spacecraft recently established contact with Earth after a brief halt with the help of a radio transmitter that has not been used since 1981. NASA engineers at Jet Propulsion Laboratory (JPL) in California re-established contact with the spacecraft on October 24.
The spacecraft, which is in interstellar space over 15 billion miles away, experienced a brief interruption in communication on October 16 due to a shutdown of one of its transmitters. This shutdown was likely triggered by the spacecraft's fault protection system, which powers down certain systems when power usage is too high.
According to NASA, a message takes around 23 hours to travel one way - from Earth to Voyager 1 and vice-versa. On October 16, when the NASA engineers sent a command to the spacecraft, they could not detect its response till October 18. A day later, communication with Voyager 1 stopped completely.
After an investigation, the space agency team discovered that Voyager 1's fault protection system had switched the spacecraft to a second, lower-power transmitter.
Voyager 1 has two radio transmitters, but has been using only one for years called an 'X-band'. However, the other transmitter - the 'S-band' - uses a different frequency which has not been employed since 1981.
Presently, NASA has opted to avoid switching back to the X-band transmitter until they can determine what activated the fault protection system - which may take weeks.
"Engineers are being cautious because they want to determine whether there are any potential risks to turning on the X-band. In the meantime, engineers sent a message to Voyager 1 on October 22 to check that the S-band transmitter was working and received confirmation on October 24. But it's not a fix the team wants to rely on for too long," Voyager mission assurance manager, Bruce Waggoner told CNN.
Voyager 1 was launched after Voyager 2, but because of a faster route it exited the asteroid belt earlier than its twin, and it overtook Voyager 2 on December 15, 1977. The spacecraft is the first human-made object to venture into interstellar space.
The spacecraft was the first to cross the heliosphere - the boundary where the influences from outside our solar system are stronger than those from the Sun.
So far, the Voyager 1 has discovered a thin ring around Jupiter and two new Jovian moons - Thebe and Metis. It also found five new moons and a new ring called 'G-Ring' at Saturn.
