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Voyager probe nears edge of interstellar space NASA NEWS RELEASE Posted: May 24, 2005 NASA's Voyager 1 spacecraft has entered the solar system's final frontier. It is entering a vast, turbulent expanse, where the sun's influence ends and the solar wind crashes into the thin gas between stars.
In November 2003, the Voyager team announced it was seeing events unlike any in the mission's then 26-year history. The team believed the unusual events indicated Voyager 1 was approaching a strange region of space, likely the beginning of this new frontier called the termination shock region. There was considerable controversy over whether Voyager 1 had indeed encountered the termination shock or was just getting close. The termination shock is where the solar wind, a thin stream of electrically charged gas blowing continuously outward from the sun, is slowed by pressure from gas between the stars. At the termination shock, the solar wind slows abruptly from a speed that ranges from 700,000 to 1.5 million mph and becomes denser and hotter. The consensus of the team is Voyager 1, at approximately 8.7 billion miles from the sun, has at last entered the heliosheath, the region beyond the termination shock. Predicting the location of the termination shock was hard, because the precise conditions in interstellar space are unknown. Also, changes in the speed and pressure of the solar wind cause the termination shock to expand, contract and ripple. The most persuasive evidence that Voyager 1 crossed the termination shock is its measurement of a sudden increase in the strength of the magnetic field carried by the solar wind, combined with an inferred decrease in its speed. This happens whenever the solar wind slows down. In December 2004, the Voyager 1 dual magnetometers observed the magnetic field strength suddenly increasing by a factor of approximately 2 1/2, as expected when the solar wind slows down. The magnetic field has remained at these high levels since December. NASA's Goddard Space Flight Center, Greenbelt, Md., built the magnetometers. Voyager 1 also observed an increase in the number of high-speed electrically charged electrons and ions and a burst of plasma wave noise before the shock. This would be expected if Voyager 1 passed the termination shock. The shock naturally accelerates electrically charged particles that bounce back and forth between the fast and slow winds on opposite sides of the shock, and these particles can generate plasma waves. "Voyager's observations over the past few years show the termination shock is far more complicated than anyone thought," said Dr. Eric Christian, Discipline Scientist for the Sun-Solar System Connection research program at NASA Headquarters, Washington. The result is being presented today at a press conference in the Morial Convention Center, New Orleans, during the 2005 Joint Assembly meeting of Earth and space
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This animation shows the Voyager spacecraft heading into the solar system's final frontier and the edge of interstellar space. (1min 24sec file)
NASA Administrator Mike Griffin and Kennedy Space Center Director Jim Kennedy chat with reporters at the Cape on a wide range of topics. The press event was held during Griffin's tour of the spaceport. (27min 48sec file)
The NOAA-N weather satellite is launched aboard a Boeing Delta 2 rocket from Vandenberg Air Force Base, California.
Officials from NASA, NOAA, the Air Force and Boeing hold the pre-launch news conference at Vandenberg Air Force Base to preview the mission of a Delta 2 rocket and the NOAA-N weather satellite. (29min 54sec file)
Watch shuttle Discovery's countdown dress rehearsal that ends with a simulated main engine shutdown and post-abort safing practice. (13min 19sec file)
The five-man, two-woman astronaut crew departs the Operations and Checkout Building to board the AstroVan for the ride to launch pad 39B during the Terminal Countdown Demonstration Test countdown dress rehearsal. (3min 07sec file)
After breakfast, the astronauts don their launch and entry partial pressure suits before heading to the pad. (3min 14sec file)
Dressed in festive Hawaiian shirts, Discovery's seven astronauts are gathered around the dining room table in crew quarters for breakfast. They were awakened at 6:05 a.m. EDT to begin the launch day dress rehearsal at Kennedy Space Center. (1min 57sec file)
As part of their training at Kennedy Space Center, the Discovery astronauts learn to drive an armored tank that would be used to escape the launch pad and receive briefings on the escape baskets on the pad 39B tower. (5min 19sec file)
Shuttle Discovery's astronauts pause their training at launch pad 39B to hold an informal news conference near the emergency evacuation bunker. (26min 11sec file)
