Before Cbadini or Galileo, there were the Voyager probes. Launched in August and September of 1977, both Voyager 1 and Voyager 2 continue to communicate with Earth through the Deep Space Network. Voyager 1 is farther from Earth than Voyager 2, due to differences in its missions and trajectories, at an estimated 141 AU from Earth (1 AU is the distance between Earth and the sun). On Friday, NASA engineers were able to successfully shoot the Voyager 1 backup thrusters for the first time in 37 years.
These small backup thrusters use hydrazine propellant and could be vital to extend the mission of Voyager 1. Maintain an open communication link to a space probe that is now more than 13 billion miles away from Earth is not easy, and requires precise adjustments in the orientation of the spacecraft. Unfortunately, since 2014, NASA has noticed that the primary propellants in Voyager were burning more and more hydrazine to make the same course corrections. With the probe billions of kilometers away, there is no chance to stop it and look under the proverbial hood.
NASA describes the difference between traditional engines and attitude control boosters as follows:
In the first days of the mission, Voyager 1 flew by Jupiter, Saturn and important moons of each. To accurately fly and point the craft's instruments at a heterogeneous mix of targets, the engineers used "trajectory correction maneuver" or TCM, propulsors identical in size and functionality to the attitude control boosters, and are located in the back of the spacecraft. . But because the last planetary encounter of Voyager 1 was with Saturn, the Voyager team did not need to use the TCM thrusters since November 8, 1980. At that time, the TCM thrusters were used in a more continuous firing mode ; they had never been used in the brief bursts needed to orient the spacecraft.
But all the propellers are of the same model, MR-103, and all of them extract propellant from the same sources. With that in mind, NASA decided to shoot the older thrusters and see if they could take care of the attitude control settings. It takes 19 hours, 35 minutes for the information to reach Voyager 1 and another 19 hours, 35 minutes for you to report home, so NASA did not get the results of the data immediately. We now know, however, that the adjustment worked perfectly, and should allow Voyager 1 to continue communicating with Earth for a few more years.
The famous image of the "pale blue dot". The Earth, each one of us, is the pale spot about half the brown strip on the right.
The long-term trajectory of the Voyager mission still ends in only one way. Thermoelectric radioisotope generators in Voyager provided 470W of power when the ship was launched, but the average life of the 238 plutonium used by the ship is 87.7 years. As of today, Voyager 1 has 72.76 percent of its plutonium 238 still in operation. By 2018, the digital tape recorder of the probe will no longer have enough power to operate. The scientific instruments will be closed in 2020, and by 2025 or 2030, the spacecraft will no longer produce enough energy to power any instrument. The use of the old TCM thrusters will allow scientists more time to collect data as Voyager continues to explore interstellar space.