NASA’s JPL are using the TCM thrusters to adjust the directions of the antenna in interstellar space.
The Voyager 1 has been an important spacecraft for NASA and the world since it left the Earth in 1977. The spacecraft has helped eager eyes look at different worlds of the solar system and even has pushed the human race into interstellar space. However, as with all spacecraft, Voyager 1 needs to correct its course while being adrift in space and NASA has discovered a new way to keep its antenna pointing the right direction.
The Voyager 1’s propulsion system has two kinds of thrusters to help it steer through space — Altitude Control Thrusters (ACT) and Trajectory Correction Manoeuvre thrusters (TCM). The ACT is responsible for keeping the antenna aligned towards Earth so as to let Voyager 1 ‘talk’ to NASA scientists. These thrusters use tiny puffs of energy to adjust the alignment of the spacecraft. Since 2014, NASA has observed that the ACT has been degrading, i.e. they are running out of energy. This could have shortened the life of the spacecraft, letting it out of reach of us earthlings.
However, NASA eggheads never like to give on their space equipment so soon and they figured out a way to save these dying thrusters — use the TCM thrusters situated at the back of the spacecraft. The TCM thrusters were responsible for giving the Voyager 1 a grand tour of some of our biggest planets in the solar system. These thrusters fired in continuous firing mode and allowed NASA to adjust the trajectory to get a perfect flyby of Jupiter, Saturn and its moons in 1980’s, after which they didn’t need it anymore and therefore shut it down. The controllers have now figured out a way to use these thrusters to adjust the alignment using brief bursts of the TCM thrusters.
On November 28, 2017, they fired up the four TCM thrusters in short 37 milliseconds bursts after a period 37 years. After a long waiting period of 19 hours and 35 minutes (that’s time it takes a message to reach from the outer space to us), the controllers in California got positive news of the thrusters working the way they wanted it to. However, there’s a major limitation to these thrusters — they need the power to operate the heater and power is something that’s getting scarce day by day on the ageing Voyager 1. The TCM will be fired in January to make the course correction and once there’s not enough power to use them, scientists will switch back to the ACT.
NASA suggests that Voyager 1 should keep on running for another 2-3 years before it runs out of fuel in the interstellar space. Not bad for a 40-years old spacecraft working constantly. Its younger sibling, the Voyager 2, is in a good shape though and will follow it to interstellar space within a few years.