Artist's concept of NASA's Voyager spacecraft. Image credit: NASA/JPL-Caltech
[/caption]
Or, more appropriately, Voyager 1 is cooling its instruments. To help conserve power, the mission managers at NASA have decided to cut the electricity to a heating element – one that’s part of the nearby infrared spectrometer that’s not been in operation for some 14 years. This power cut will lower the temperature of the ultraviolet spectrometer by about 23 degrees Celsius (41 degrees Fahrenheit)… a temperature that’s mild compared to the below minus 79 degrees Celsius (minus 110 degrees Fahrenheit) that the instrument has dropped to in previous times. It’s not a drastic measure, however, but all part of a crucial plan to manage electrical power to keep the spacecraft operational and transmitting data for another 13 years.
Just because the power is cut back doesn’t mean the instrument quit working. At the present, the spectrometer is continuing to gather and transmit data. The resilient system was designed to work in temperatures as frosty as minus 35 degrees Celsius (minus 31 degrees Fahrenheit) and has even operated beyond the call of duty when heaters were switched off over the last 17 years. While it was taking a chance that the equipment might malfunction, the engineering team was confident since the spectrometer has worked at minus 56 degrees Celsius (minus 69 degrees Fahrenheit.) since 2005. “The spectrometer is likely operating at a temperature somewhat lower than minus 79 degrees Celsius, or minus 110 degrees Fahrenheit,” says the team. “But the temperature detector does not go any lower.”
While it has been awhile since Voyager 1’s encounter with Jupiter and Saturn which made the spectrometer busy, that doesn’t mean its data will be disregarded. Both scientists and mission management specialists will continue to monitor performance levels and an international team of scientists will further review spectrometer data.
The Voyager 1 spacecraft has started to transverse what JPL has dubbed as a "cosmic purgatory" between our solar system - and interstellar space. Image Credit: NASA/JPL
[/caption]
Voyager 1 is in uncharted territory. The long-lived spacecraft has entered a new region of space that lies between where our solar system ends and where interstellar space begins. This area is not a place of sightseeing however, as a NASA press release referred to it as a kind of “cosmic purgatory.”
Here, the solar winds ebb somewhat, the magnetic field increases and charged particles from within our solar system – is leaking out into interstellar space. This data has been compiled from information received from Voyager 1 over the course of the last year.
The Voyager spacecraft's compliment of scientific instruments have provided scientists back on Earth with information about what the space environment at the fringes of our sun's influence is truly like. Image Credit: NASA/JPL - Caltech
“Voyager tells us now that we’re in a stagnation region in the outermost layer of the bubble around our solar system,” said Ed Stone, Voyager project scientist at the California Institute of Technology in Pasadena. “Voyager is showing that what is outside is pushing back. We shouldn’t have long to wait to find out what the space between stars is really like.”
Despite the fact that Voyager 1 is approximately 11 billion miles (18 billion kilometers) distant from the sun – it still has not encounter interstellar space. The information that scientists have gleaned from the Voyager 1 spacecraft indicates that the spacecraft is still located within the heliosphere. The heliosphere is a “bubble” of charged particles that the sun blows around itself and its retinue of planets.
Voyager 1 has traveled far past the realm of the gas or even ice giants and is now in uncharted territory where scientists are learning more and more about the dynamic environment at the far-flung edges of our solar system. Image Credit: NASA/JPL - Caltech
The latest findings were made using Voyager’s Low Energy Charged Particle instrument, Cosmic Ray Subsystem and Magnetometer.
Experts are not certain how long it will take the Voyager 1 spacecraft to finally breach this bubble and head out into interstellar space. Best estimates place the length of time when this could happen anywhere from the next few months – to years. These findings counter findings announced in April of 2010 that showed that Voyager 1 had essentially crossed the heliosphere boundary. The discoveries made during the past year hint that this region of space is far more dynamic than previously thought.
Voyager 1 has entered into a region of space between the sun's influence and the beginning of interstellar space that NASA has dubbed the "stagnation region." Image Credit: NASA/JPL - Caltech
The magnetometer aboard Voyager 1 has picked up an increase in the intensity of the magnetic field located within this “stagnation field.” Essentially the inward pressure from interstellar space is compressing the magnetic field to twice its original density. The spacecraft has also detected a 100-fold increase in the intensity of high-energy electrons diffusing into our solar system from outside – this is yet another indicator that Voyager 1 is approaching the heliosphere.
The interplanetary probe was launched from Cape Canaveral Air Force Station’s Space Launch Complex 41 (SLC-41) on Sept. 5, 1977, Voyager 1’s sister ship, Voyager 2 is also in good health and is about 9 billion miles (15 billion kilometers) from the sun (it too was launched in 1977). The spacecraft itself was built by NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
“Voyager is a mission of discovery and it’s at the edge of the solar system still making discoveries,” said Stone said. “The stagnation is the latest in the whole journey of discovery. We are all excited because we believe it means we’re getting very close to boundary of heliosphere and the entry into interstellar space.”
Both of the Voyager spacecraft were thrust to orbit by the powerful Titan boosters - and both in the same year - 1977. Photo Credit: NASA
