During the early days of the mission, Voyager 1 flew by Jupiter, Saturn and important moons of each.
Voyager was launched in 1977 and is now the only spacecraft in interstellar space, or the area beyond the solar system. NASA's Jet Propulsion Laboratory compared the feat to successfully starting up a auto that had been sitting idle in the garage for 37 years. We now know, however, that the adjustment worked perfectly, and it should allow Voyager 1 to keep communicating with Earth for a few more years.
NASA engineers have to resort to a set of thrusters called "trajectory correction maneuver" (TCM) since the ones that they have been using have degraded past beyond an acceptable point.
To NASA's delight, the four dormant thrusters came alive.
This is done by a series of puffs from thrusters aboard the craft - small puffs that fire only mere milliseconds, and are more than enough to orient Voyager 1 towards our planet, as NASA explained in their news update last Friday, Dec. 1.
NASA receives transmission from a spacecraft that's 13 billion miles away from Earth
As of August, Voyager 1 was almost 13 billion miles from Earth, and Voyager 2 about 11 billion miles out.
"The Voyager team got more excited each time with each milestone in the thruster test". Voyager 1 also has "trajectory correction maneuver" thrusters or TCMs, but they worked differently and were used for a different goal, despite having the same build. But because Voyager 1's last planetary encounter was Saturn, the Voyager team hadn't needed to use the TCM thrusters since November 8, 1980. It takes 19 hours, 35 minutes for information to reach Voyager 1 and another 19 hours, 35 minutes for it to report home, so NASA didn't get the results of the data immediately. The attitude control thrusters now used for Voyager 2 are not yet as diminished as Voyager 1's, however. The test went so well, that the team will also do a similar test on the TCM thrusters for Voyager 2, the twin spacecraft of Voyager 1.
On Tuesday, Nov. 28, 2017, Voyager engineers fired up the four TCM thrusters for the first time in 37 years and tested their ability to orient the spacecraft using 10-millisecond pulses.
The last time these engines were run in 1980.