Voyager 1: 'The Spacecraft That Could' Hits New Milestone
August 15, 2006
Voyager 1, already the most distant human-made object
in the cosmos, reaches 100 astronomical units from the
sun on Tuesday, August 15 at 5:13 p.m. Eastern time (2:13
p.m. Pacific time). That means the spacecraft, which
launched nearly three decades ago, will be 100 times
more distant from the sun than Earth is.
In more common terms, Voyager 1 will be about 15 billion
kilometers (9.3 billion miles) from the sun. Dr. Ed Stone,
Voyager project scientist and the former director of
NASA's Jet Propulsion Laboratory in Pasadena, Calif.,
says the Voyager team always predicted that the spacecraft
would have enough power to last this long.
"But what you can't predict is that the spacecraft
isn’t going to wear out or break. Voyager 1 and
2 run 24 hours a day, seven days a week, but they were
built to last," Stone said. The spacecraft have
really been put to the test during their nearly 30 years
of space travel, flying by the outer planets, and enduring
such challenges as the harsh radiation environment around
The spacecraft are traveling at a distance where the
sun is but a bright point of light and solar energy is
not an option for electrical power. The Voyagers owe
their longevity to their nuclear power sources, called
radioisotope thermoelectric generators, provided by the
Department of Energy.
Voyager 1 is now at the outer edge of our solar system,
in an area called the heliosheath, the zone where the
sun's influence wanes. This region is the outer layer
of the 'bubble' surrounding the sun, and no one knows
how big this bubble actually is. Voyager 1 is literally
venturing into the great unknown and is approaching interstellar
space. Traveling at a speed of about one million miles
per day, Voyager 1 could cross into interstellar space
within the next 10 years.
"Interstellar space is filled with material ejected
by explosions of nearby stars," Stone said. "Voyager
1 will be the first human-made object to cross into it."
Voyager Project Manager Ed Massey of
JPL says the survival of the two spacecraft is a credit
to the robust design
of the spacecraft, and to the flight team, which is now
down to only 10 people. "But it’s these 10
people who are keeping these spacecraft alive. They’re
very dedicated. This is sort of a testament to them,
that we could get all this done."
Between them, the two Voyagers have explored Jupiter,
Uranus, Saturn and Neptune, along with dozens of their
moons. In addition, they have been studying the solar
wind, the stream of charged particles spewing from the
sun at nearly a million miles per hour.