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WG3K > ANS 16.06.24 02:23l 74 Lines 3775 Bytes #85 (0) @ AMSAT
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Subj: Voyager 1 is Back To Life, But For How Long?
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Sent: 240616/0018Z 5362@WG3K.#SMD.MD.USA.NOAM LinBPQ6.0.24
NASA engineers have succeeded in breathing new life into Voyager 1, the
spacecraft launched in 1977 and once again communicating after it went
silent seven months ago. But now comes another challenge: Keeping Voyager 1
scientifically useful for as long as possible as it probes a realm where no
spacecraft has gone before.
Voyager 1 and its twin, Voyager 2, are treasured at NASA not only because
they have sent home astonishing images of the outer planets, but also
because in their dotage, they are still doing science that canâ€Öt be readily
duplicated.
They are now in interstellar space, far beyond the orbits of Neptune and
Pluto. Voyager 1 is more than 15 billion miles from Earth and Voyager 2
nearly 13 billion miles. Both have passed the heliopause, where the “solar
wind” of particles streaming from the sun terminates.
“Theyâ€Öre going someplace where we have nothing, we have no information,”
NASA Deputy Administrator Pam Melroy said. “We donâ€Öt know anything about
the interstellar medium. Is it a highly charged environment? Are there a
lot of dust particles out there?”
*Ed Stone, who guided the mission from 1972 until 2022, died on June 9.
(Luis Sinco/Los Angeles Times/Getty Images)*
Even as the Voyagers continue their journeys, engineers and scientists at
the NASA Jet Propulsion Laboratory in Pasadena, Calif. are mourning the
loss of Ed Stone, the scientist who guided the mission from 1972 until his
retirement in 2022. Stone, a former director of JPL, died June 9 at the age
of 88.
Voyager 1 has four scientific instruments still operational in this
extended phase of its mission, but it suddenly ceased sending intelligible
data on Nov. 14. A “tiger team” of engineers at JPL spent the ensuing
months identifying the problem â€ö a malfunctioning computer chip â€ö and
restoring communication.
What no one can change, though, is the mortality of a spacecraft with a
limited power supply. Voyager 1 is running on fumes, or, more precisely, on
the dwindling power from the radioactive decay of plutonium. The Voyagers
use a radioisotope thermoelectric generator. But an RTG doesnâ€Öt last
forever. Voyager 1 and Voyager 2 will eventually go silent as they continue
to cruise the galaxy.
“At some point, weâ€Öll have to start turning off the science instruments one
by one,” project scientist Linda Spilker said. “Once weâ€Öre out of power,
then we can no longer keep the spacecraft pointed at the Earth. And so [the
Voyagers] will then continue on as what I like to think of as our silent
ambassadors.”
In a sense, this is all a bonus because the primary mission for the two
Voyagers was the exploration of the outer planets. Both visited Jupiter and
Saturn, and Voyager 2 went on to Uranus and Neptune in what was known as
the “Grand Tour” of the outer solar system, enabled by a rare orbital
arrangement of the planets. The Voyagers delivered spectacular close-up
images of the outer planets, and the mission ranks among NASAâ€Ös greatest
achievements.
The gravitational slingshot from the planetary encounters sent Voyager 1
out of the elliptical plane of the solar system and did the same to Voyager
2 in a different direction.
About four years ago, Voyager 1 encountered something unexpected â€ö a
phenomenon scientists have dubbed a pressure front. Jamie Rankin, deputy
project scientist, said the instruments on the spacecraft picked up a
sudden change in the magnetic field of the interstellar environment, as
well as a sudden increase in the density of particles.
What exactly caused this change remains unknown. But NASA scientists are
eager to get all the data flowing normally again to see whether the
pressure front is still detectable.
[ANS thanks The New York Times for the above information
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