NASA
NASA’s Voyager 2 probe, launched on August 20, 1977, has been operating in space for 45 years.Its brother Voyager 1, which was launched a few days later, was launched on September 5 and is about to cross its 45th anniversary.Both are NASA’s longest ongoing missions。
The Voyager series of probes took advantage of a unique launch window in 1977, allowing the probes to continuously use the gravitational boost of Jupiter and Saturn to detect the more distant Uranus and Neptune in succession without much fuel. Among the two probes, Voyager 2 was the first to launch, but due to a slight difference in orbit, Voyager 1 passed Jupiter first in March 1979 and arrived at Saturn in November 1980. At Saturn, NASA astronomers decided to prioritize the observation of Titan (Titan) with a thick atmosphere, so Voyager 1 was set to pass Titan at the best angle, but could not continue to move towards other planets. ‘s channel. After bypassing Titan, Voyager 1 left the ecliptic plane and headed towards the edge of the solar system.
Voyager 2, which arrived more slowly, passed Jupiter in July 1979 and Saturn in August 1981, and then passed by in January 1986 and September 1989, respectively, according to the original plan. Uranus and Neptune. After leaving many photos, Voyager 2 also left the ecliptic plane and headed towards the edge of the solar system in the other direction. The lonely and long journey of the two has ushered in changes in 2012 and 2018 respectively.The first is that Voyager 1 detected charged particles from outer space for the first time in 2012 – because the sun continues to send out the solar wind, and the solar wind will isolate these charged particles, so this can be regarded as Voyager 1 has beenbeyond the reach of the solar wind, entered the “interstellar space”. The slower Voyager 2 took a few more years, but also entered interstellar space in 2018. This is not the first human probe to enter interstellar space, but it is the only two still in operation, bringing us valuable information on the state of interstellar space.
Both Voyager probes use “radioisotope thermoelectric machines” as their power sources, that is, they use the heat energy generated by the decay of nuclear substances they carry to generate electricity. However, as the plutonium-238 on board gradually decays, the generator can provide less and less power, so scientists have to gradually turn off scientific research equipment and even necessary life-sustaining equipment to keep the detector operating at a minimum. Taking Voyager 2 as an example, the main imaging equipment was shut down in 1998, the tape data recorder was shut down in 2007, the radio observation equipment was shut down in 2008, and in 2019, even the instruments that were still operating were closed. The thermal insulation also had to be turned off, but fortunately, even though the temperature was well below the designed limit, this did not seem to affect the operation of the instrument.
NASA currently estimates that around 2025, Voyager’s power wattage will be too low to sustain any scientific instrumentation, and 2036 is the limit for Voyager’s communication system to connect to the deep space network and transmit data. NASA’s current plan is to announce the end of the Voyager mission in 2025 after closing the final scientific instruments, so we may not have the opportunity to celebrate the Voyager mission’s 50th anniversary.