Despite the fact that its power source is becoming fainter
and its communications must travel a greater distance, this remarkable
spacecraft is not yet finished.
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Voyager 2’s scientific instruments have got a reprieve |
All of Voyager 2’s scientific instruments will continue to
operate until 2026 thanks to a small supply of backup power that has been
activated to delay a planned shutdown this year. By carrying out the operation,
humanity will be able to keep two eyes on the universe outside of the
heliosphere, where the solar wind dominates interstellar space.
There is a compelling argument. The most important
scientific tool in history is Voyager 2. It is the only spacecraft to have
visited Uranus and Neptune, and for a while, it will be the primary source of
the majority of the information we have about those planets. While this was
going on, its observations of Jupiter and Saturn were just as important as
those of its twin, Voyager 1, in letting us know what areas future missions
should concentrate on. Although its scientific output has decreased since
leaving Neptune, it has still contributed to mapping the heliopause’s
boundaries and discovered an unexpected rise in density outside the Solar
System.
The Jet Propulsion Laboratory’s Dr. Linda Spilker, the
project scientist for the Voyager spacecraft, said in a statement that
“the science data that the Voyagers are returning gets more valuable the
farther from the Sun they go. Therefore, we are definitely interested in
keeping as many science instruments operating as long as possible.”
Voyager 2 was launched with the sole goal of keeping it
operational until it arrived at Neptune 12 years later. The prospect that it
might continue to work 34 years later was not given any thought. The energy for
both Voyagers comes from the breakdown of plutonium atoms, which provide heat
that thermoelectric generators can, albeit imperfectly, turn into electricity.
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Voyager 2 is powered by three radioisotope thermoelectric |
This was just 470 Watts even at launch, which is less than
the typical household in a developed nation consumes. With a half-life of 88
years, enough plutonium has decayed for this power to be around 30% lower at
this time.
NASA has been able to keep the others running by gradually
turning down heaters, moving to backup thrusters, and turning off other no-longer-needed equipment, but that procedure can’t continue on indefinitely. It
was anticipated that at least one instrument would cease to function this year,
but Spilker and colleagues discovered that a voltage regulator needed a little
amount of power to keep the instruments safe from power surges.
The five scientific instruments are all slightly at danger
when the regulator is turned off, but this was deemed better than shutting down
one to make room for the others. The operators decided to make the change
permanent after a few weeks of testing operations without the regulator.
By 2026, it will still be necessary to decide which
instrument to play first, barring any additional miracles.
Compared to its twin, Voyager 1 uses a little less energy
because one of its instruments malfunctioned early on. If eliminating the
regulator for Voyager 2 is successful, Voyager 1 will likely follow suit in a
year.