Page 72 - BBC Sky at Night - September 2017 UK

72 VOYAGER AT 40 SEPTEMBER

The spacecraft and its instruments

Each Voyager is the size of a small car, has a 3.7m high-gain antenna and launched with 11 scientific instruments

Plasma spectrometer Low-energy charged
Radio Science System particle detector
Magnetometer Defective on Voyager 1;
Used communications active on Voyager 2 Measures cosmic radiation,
Investigates magnetic system to determine and analyses interplanetary
fields of planets, their planets’ physical Cosmic ray subsystem energetic particles.
moons, interplanetary properties Active on both
space, the solar wind Studies energetic particles
and interstellar space. Active on both
Active on both Ultraviolet spectrometer
Disabled on both.
Radioisotope thermoelectric
generators
Imaging
Supplies power for the spacecraft systems science system
Plasma wave antenna Narrow- and wide-
angle camera system.
Studied plasma Optical Disabled on both
(ionised gas) signals calibration
from planetary rings; target and Infrared
continues to study radiator radiometer,
plasma in interstellar interferometer
space. Partially disabled Planetary radio and spectrometer
on Voyager 2; Active antenna Bus Photopolarimeter
on Voyager 1 Defective on Voyager 1; Disabled on both
Disabled on both Main body housing disabled on Voyager 2
electronics

Voyager 1 has now left
the heliosphere, with
Voyager 2 expected
to follow in the next
five years

<! Neptune had a huge
storm named the Great
Dark Spot (left) while its
moon Triton was found to
have ice geysers (above)

> the beginning of the Interstellar Mission. In 1998, as they are sending us something new to learn,”
Voyager 1 overtook Pioneer 10 to become the explains Ed Stone. From 2020, however, the
most distant spacecraft from the Sun. Voyager 2 remaining instruments will be switched off one by
is expected to pass Pioneer 10 by April 2019. one to conserve power. It’s hoped they will fly for
In December 2004, Voyager 1 crossed the at least 10 more years. “My goal is to have a 50th
NASA/JPL-CALTECH X 3, MARK GARLICK ray particles. Voyager 2 followed in August 2007. ABOUT THE WRITER ambassadors”. In 40,000 years, they will each
anniversary party for Voyager,” says Suzanne Dodd,
termination shock, marked by a massive drop in
project manager of the Voyager Interstellar Mission.
particles detected from the Sun and a rise in cosmic
Stone considers the Voyagers to be “our silent
Finally, on 25 August 2012, at 121 AU from the Sun,
Jenny Winder is a
science writer
pass 1.5 lightyears from stars in Andromeda and
Voyager 1 officially crossed into interstellar space.
and broadcaster
Camelopardalis. Having increased our knowledge
The Voyager team is still listening. “We listen
with a passion for
of our solar neighbourhood, the Voyagers will take
every day, for four to eight hours per day, per
spacecraft, and we’ll continue to do that as long
skyatnightmagazine.com 2017 astronomy outreach the story of Earth on to other star systems. S