NASA just got a response from an inactive spacecraft 13 billion miles away
On September 5, 1977, the NASA spacecraft Voyager 1 was launched from the Kennedy Space Center Launch Complex in Florida. Since then, other Voyager probes have been launched, but this particular model has remained the one that has travelled the furthest away. In fact, it is the only human-made object that has made it to interstellar space.
The Voyager spacecraft travels at speed of over 35,000 miles per hour, which means it can travel approximately 900,000 miles further from our planet with each passing day. To put that monumentally huge number into perspective, this is equal to roughly 26 times Earth's circumference.
When an object is is travelling at these speeds, with several decades to put distance between it and its planet of origin, there is a lot that can go wrong. Now, Voyager 1 has reported that it has fired up its thrusters after 37 years of inactivity, meaning that these instruments have remained functional despite nearly four decades of disuse and four decades since the spacecraft's launch. Amazingly, this means it can now communicate with Earth, despite being 13 billion miles away.
The reason for this lack of communication is that the Voyager relies on its thrusters to correctly position itself, so that it can aim its signal to our planet - a very specific angle when you're billions of miles away. These thrusters fire in tiny pulses which last milliseconds, making subtle changes to the position of its antenna.
In 2012, Voyager 1 crossed the edge of the heliosphere, called the heliopause, venturing for the first time into the space between stars, where no other human-made object had gone before. Two years later, NASA realised that the thrusters on board the Voyager 1 were degrading at a fast rate. NASA’s Jet Propulsion Laboratory analysed options and predicted how the space probe would respond to different scenarios.
This team, which was made up of Chris Jones, Carl Guernsey, Robert Shotwell, and Todd Barber, agreed to take the risk of giving the job of orientation to a set of thrusters that had been inactive for four decades. Jones, chief engineer at the JPL, said that they "dug up decades-old data and examined the software that was coded in an outdated assembler language, to make sure we could safely test the thrusters."
On November 28, Voyager engineers fired up the thrusters and tested it out, sending a signal from the spacecraft back to its point of origin. 19 hours and 35 minutes later, the signal reached NASA's Deep SpaceNetwork, located in Goldstone, California.
"The Voyager team got more excited each time with each milestone in the thruster test," Todd Barber said. "The mood was one of relief, joy and incredulity after witnessing these well-rested thrusters pick up the baton as if no time had passed at all."
Suzanne Dodd, who works as the project manager for Voyager at NASA’s Jet Propulsion Laboratory unit, pointed out that this surprise will likely extend the life of the Voyager 1 by two to three years.