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An artist's concept of Voyager 1
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NASA's two venerable Voyager spacecraft are celebrating
three decades of flight as they head toward interstellar space. Their
ongoing odysseys mark an unprecedented and historic accomplishment.
Voyager 2 launched on Aug. 20, 1977, and Voyager 1 launched on Sept.
5, 1977. They continue to return information from distances more than
three times farther away than Pluto.
"The Voyager mission is a legend in the annals of space exploration.
It opened our eyes to the scientific richness of the outer solar
system, and it has pioneered the deepest exploration of the sun's
domain ever conducted, " said Alan Stern, associate administrator for
NASA's Science Mission Directorate, Washington. "It's a testament to
Voyager's designers, builders and operators that both spacecraft
continue to deliver important findings more than 25 years after their
primary mission to Jupiter and Saturn concluded."
During their first dozen years of flight, the spacecraft made detailed
explorations of Jupiter, Saturn, and their moons, and conducted the
first explorations of Uranus and Neptune. These planets were
previously unknown worlds. The Voyagers returned never-before-seen
images and scientific data, making fundamental discoveries about the
outer planets and their moons. The spacecraft revealed Jupiter's
turbulent atmosphere, which includes dozens of interacting
hurricane-like storm systems, and erupting volcanoes on Jupiter's
moon Io. They also showed waves and fine structure in Saturn's icy
rings from the tugs of nearby moons.
For the past 19 years, the twin Voyagers have been probing the sun's
outer heliosphere and its boundary with interstellar space. Both
Voyagers remain healthy and are returning scientific data 30 years
after their launches.
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Artist concept of the two Voyager spacecraft as they approach interstellar space.
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Voyager 1 currently is the farthest human-made object at a distance
from the sun of about 9.7 billion miles. Voyager 2 is about 7.8
billion miles from the sun. Originally designed as a four-year
mission to Jupiter and Saturn, the Voyager tours were extended
because of their successful achievements and a rare planetary
alignment. The two-planet mission eventually became a four-planet
grand tour. After completing that extended mission, the two
spacecraft began the task of exploring the outer heliosphere.
"The Voyager mission has opened up our solar system in a way not
possible before the Space Age, " said Edward Stone, Voyager project
scientist at the California Institute of Technology, Pasadena, Calif.
"It revealed our neighbors in the outer solar system and showed us
how much there is to learn and how diverse the bodies are that share
the solar system with our own planet Earth."
In December 2004, Voyager 1 began crossing the solar system's final
frontier. Called the heliosheath, this turbulent area, approximately
8.7 billion miles from the sun, is where the solar wind slows as it
crashes into the thin gas that fills the space between stars. Voyager
2 could reach this boundary later this year, putting both Voyagers on
their final leg toward interstellar space.
Each spacecraft carries five fully functioning science instruments
that study the solar wind, energetic particles, magnetic fields and
radio waves as they cruise through this unexplored region of deep
space. The spacecraft are too far from the sun to use solar power.
They run on less than 300 watts, the amount of power needed to light
up a bright light bulb. Their long-lived radioisotope thermoelectric
generators provide the power.
"The continued operation of these spacecraft and the flow of data to
the scientists is a testament to the skills and dedication of the
small operations team, " said Ed Massey, Voyager project manager at
NASA's Jet Propulsion Laboratory in Pasadena, Calif. Massey oversees
a team of nearly a dozen people in the day-to-day Voyager spacecraft
operations.
The Voyagers call home via NASA's Deep Space Network, a system of
antennas around the world. The spacecraft are so distant that
commands from Earth, traveling at light speed, take 14 hours one-way
to reach Voyager 1 and 12 hours to reach Voyager 2. Each Voyager logs
approximately 1 million miles per day.
Each of the Voyagers carries a golden record that is a time capsule
with greetings, images and sounds from Earth. The records also have
directions on how to find Earth if the spacecraft is recovered by
something or someone.
NASA's next outer planet exploration mission is New Horizons, which is
now well past Jupiter and headed for a historic exploration of the
Pluto system in July 2015.
For a complete listing of Voyager discoveries and mission information,
visit the Internet at: http://www.nasa.gov/voyager
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