The absolutely most amazing thing of all about this story: 35 years after it was launched Voyager 1 is still sending back data and we are able to receive its signal even though it is nearing interstellar space where the sun's heliosphere stops. If we built a space probe to send beyond the solar system today would we use technology that lasts as long?
"Although Voyager 1 still is inside the sun's environment, we now can taste what it's like on the outside because the particles are zipping in and out on this magnetic highway," said Edward Stone, Voyager project scientist based at the California Institute of Technology, Pasadena. "We believe this is the last leg of our journey to interstellar space. Our best guess is it's likely just a few months to a couple years away. The new region isn't what we expected, but we've come to expect the unexpected from Voyager."
Since December 2004, when Voyager 1 crossed a point in space called the termination shock, the spacecraft has been exploring the heliosphere's outer layer, called the heliosheath. In this region, the stream of charged particles from the sun, known as the solar wind, abruptly slowed down from supersonic speeds and became turbulent. Voyager 1's environment was consistent for about five and a half years. The spacecraft then detected that the outward speed of the solar wind slowed to zero.
The intensity of the magnetic field also began to increase at that time.
Voyager data from two onboard instruments that measure charged particles showed the spacecraft first entered this magnetic highway region on July 28, 2012. The region ebbed away and flowed toward Voyager 1 several times. The spacecraft entered the region again Aug. 25 and the environment has been stable since.
"If we were judging by the charged particle data alone, I would have thought we were outside the heliosphere," said Stamatios Krimigis, principal investigator of the low-energy charged particle instrument, based at the Johns Hopkins Applied Physics Laboratory, Laurel, Md. "But we need to look at what all the instruments are telling us and only time will tell whether our interpretations about this frontier are correct."
So where does Voyager get the electricity to send a signal back to Earth? plutonium-238 nuclear power. The US stopped producing it in 1992. But this has been restarted to use in future space probes.
What I'd like to know: Could we build a probe with today's technology that would use nuclear propulsion to get into interstellar space much more quickly? 35+ years to get a probe to interstellar space is just too long.
|Share |||Randall Parker, 2012 December 03 09:51 PM|