Why does NASA stop systems on Voyager 2 while it's flying into interstellar space?

TheLaunched in 1977, NASA engineers managed to fly the Voyager 1 and 2 satellites for nearly 42 years – longer than any other spaceship in history. But as announced on July 8 NASA's Jet Propulsion Laboratory, it's time to close some parts of Voyager 2.

Voyager 2 is more than 11.2 billion kilometers from Earth, but its travel speed is 34,391 miles per hour, or 10 miles per second, so the distance is increasing rapidly. In December 2018, it became the second object created by humans, after Voyager 1, to penetrate into what is considered an interstellar space. This happened as he was crossing the heliosphere, the ionized particle bubble that envelops the solar system.

And it still sends data that is picked up by radio telescopes in Australia.

But to ensure that these probes of the past continue to send the best possible scientific data to the boundaries of space, the mission engineers were forced to implement a new plan to manage them. This involves making difficult choices, especially with regard to instruments and thrusters.

A key problem with both Voyager vehicles is that they have less and less energy over time to operate their scientific instruments and the heaters that keep them running in the cold of space. The engineers had to decide which parts would be powered and which parts had to be turned off on both spacecraft.

But these decisions need to be made earlier for Voyager 2 than for Voyager 1, because Voyager 2 has an additional scientific instrument to collect data – and draw its energy – from its siblings.

After extensive discussions with Voyager's science team, mission officials announced Monday that they have shut down a heater for the Cosmic Ray Subsystem (CBC) instrument on Voyager 2 as part of of the new food management plan. The cosmic ray instrument played a crucial role last November in determining whether the Voyager 2 was out of the heliosphere. Since then, the two Voyageurs have returned details of how our heliosphere interacts with the wind in space.

Why did he have to be the instrument of the cosmic ray subsystem?

According to the JPL, mission team members can now preliminarily confirm that the Voyager 2 CRS is standards compliant. again back data, despite a drop of -59 ° C (-74 ° F). This is below the temperatures at which the CRS was tested over 42 years ago (up to -49 ° F or -45 ° C). So, that already exceeds expectations.

But the operation of heaters and instruments requires current, which is constantly decreasing for both travelers.

Each of the probes is powered by three thermoelectric radioisotope generators (RTGs), which produce heat through the natural decay of the plutonium 238 radioisotopes and convert this heat into electrical energy. As the thermal energy of plutonium in GTR decreases and their internal efficiency decreases over time, each spacecraft produces about 4 watts of electrical energy less each year. This means that the generators produce about 40% less than the launch nearly 42 years ago, limiting the number of systems that can operate on the spacecraft.

So, for example, if the fuel lines that power the thrusters that keep the spacecraft freeze, the antennas of Voyagers could stop pointing to the Earth. This would prevent engineers from sending commands to the spacecraft or receiving scientific data.

The Mission's new energy management plan explores many options to address the decreasing energy supply to both spacecraft, including the shutdown of additional space heating radiators in the coming years. JPL engineers will try to ensure that both spacecraft can continue to collect data from interstellar space for years. It is hoped that Voyager 2 will continue to transmit weak radio messages until the mid-2020s.

What does the universe have in store for Voyager?

Voyager 2 is not heading for a particular star, although in about 42,000 years it will be 1.7 light years ahead of the small red dwarf star Ross 248, located in the northern constellation of Andromeda. If the probe is not disturbed for 296,000 years, Voyager 2 is expected to be 4.3 light years ahead of star Sirius, the brightest star in the night sky. Delta Pavonis and Gliese 754, about 100,000 years later.

It is possible that Voyager 2 survives the human race.

After leaving the heliosphere and entering interstellar space, the next cosmological phenomenon that Voyager 2 will encounter is the Cloud of Oort, in 300 years. Unfortunately, it will be long after the power is exhausted.

The Oort cloud is a theoretical cloud composed mainly of frozen planetesimals, supposed to surround the sun at distances up to 200,000 AU (3.2 light-years). The outer limit of the Oort cloud defines the limit of the solar system, because that is where the gravitational influence of our sun ends. But it's a big cloud: it will take more than 30 000 years for Voyager 2 to cross it.

Alone, up there, in the dark

The two spacecraft have captivated the imagination of science fiction writers and scientists, which is not surprising if you take a moment and imagine that you are plummeting in a deep and totally unexplored space. Maybe forever.

One of the best-known examples is that of Star Trek: the movie, which was released in 1979. In this, the first of the big-screen features of Star Trek, the crew of Enterprise must determine the purpose of a giant alien spaceship threatening to extinguish all life on Earth. And what we know, at the heart of this huge alien ship is a Voyager probe. (It's actually a fiction called Voyager 6, but that's beside the question.)

Kirk, McCoy, Spock et al. Discover to their astonishment that during its mission, the Voyager probe disappeared into a black hole and emerged on the other side of the galaxy, where it fell into the gravitational field of a planet populated by living machines.

The inhabitants found that the probe was unique in its kind: primitive, but nevertheless related. Discovering its simple twentieth-century programming, which required Voyager to collect all possible data and return it to the creator, the machines literally interpreted it and built an enormous ship around the probe to facilitate the implementation of this directive.

When he returned to Earth, he accumulated so much knowledge that he reached consciousness itself, becoming a living thing.

Until that this In this case, you can check the speed and trajectory of Voyager 1 and 2 in real time on the mission status page of NASA.