More than 30 years after they left Earth, NASA’s twin Voyager probes are now at the edge of the solar system. Not only that, they’re still working. And with each passing day they are beaming back a message that, to scientists, is both unsettling and thrilling.

The message is, "Expect the unexpected."

"It’s uncanny," says Ed Stone of the California Institute of Technology in Pasadena, Voyager Project Scientist since 1972. "Voyager 1 and 2 have a knack for making discoveries."

Today, April 28, 2011, NASA held a live briefing to reflect on what the Voyager mission has accomplished–and to preview what lies ahead as the probes prepare to enter the realm of interstellar space in our Milky Way galaxy.

The adventure began in the late 1970s when the probes took advantage of a rare alignment of outer planets for an unprecedented Grand Tour. Voyager 1 visited Jupiter and Saturn, while Voyager 2 flew past Jupiter, Saturn, Uranus and Neptune.  (Voyager 2 is still the only probe to visit Uranus and Neptune.)

When pressed to name the top discoveries from those encounters, Stone pauses, not for lack of material, but rather an embarrassment of riches. "It’s so hard to choose," he says.

Stone’s partial list includes the discovery of volcanoes on Jupiter’s moon Io; evidence for an ocean beneath the icy surface of Europa; hints of methane rain on Saturn’s moon Titan; the crazily-tipped magnetic poles of Uranus and Neptune; icy geysers on Neptune’s moon Triton; planetary winds that blow faster and faster with increasing distance from the sun.

"Each of these discoveries changed the way we thought of other worlds," says Stone.  In 1980, Voyager 1 used the gravity of Saturn to fling itself slingshot-style out of the plane of the solar system. In 1989, Voyager 2 got a similar assist from Neptune. Both probes set sail into the void.

Sailing into the void sounds like a quiet time, but the discoveries have continued.  Stone sets the stage by directing our attention to the kitchen sink. "Turn on the faucet," he instructs. "Where the water hits the sink, that’s the sun, and the thin sheet of water flowing radially away from that point is the solar wind. Note how the sun ‘blows a bubble’ around itself."

There really is such a bubble, researchers call it the "heliosphere," and it is gargantuan. Made of solar plasma and magnetic fields, the heliosphere is about three times wider than the orbit of Pluto. Every planet, asteroid, spacecraft, and life form
belonging to our solar system lies inside.

The Voyagers are trying to get out, but they’re not there yet. To locate them, Stone peers back into the sink: "As the water [or solar wind] expands, it gets thinner and thinner, and it can’t push as hard. Abruptly, a sluggish, turbulent ring forms. That outer ring is the heliosheath–and that is where the Voyagers are now."

The heliosheath is a very strange place, filled with a magnetic froth no spacecraft has ever encountered before, echoing with low-frequency radio bursts heard only in the outer reaches of the solar system, so far from home that the sun is a mere pinprick of light.

"In many ways, the heliosheath is not like our models predicted,” says Stone.  In June 2010, Voyager 1 beamed back a startling number: zero. That’s the outward velocity of the solar wind where the probe is now. No one thinks the solar wind has completely stopped; it may have just turned a corner. But which way? Voyager 1 is trying to figure that out through a series of "weather vane" maneuvers, in which the spacecraft turns itself in a different direction to track the local breeze. The old spacecraft still has some moves left, it seems.

No one knows exactly how many more miles the Voyagers must travel before they "pop free" into interstellar space. Most researchers believe, however, that the end is near. "The heliosheath is 3 to 4 billion miles in thickness," estimates Stone. "That means we’ll be out within five years or so."

There is plenty of power for the rest of the journey. Both Voyagers are energized by the radioactive decay of a Plutonium 238 heat source. This should keep critical subsystems running through at least 2020.

After that, he says, "Voyager will become our silent ambassador to the stars."  Each probe is famously equipped with a Golden Record, literally, a gold-coated copper phonograph record. It contains 118 photographs of Earth; 90 minutes of the world’s greatest music; an audio essay entitled Sounds of Earth (featuring everything from burbling mud pots to barking dogs to a roaring Saturn 5 liftoff); greetings in 55 human languages and one whale language; the brain waves of a young woman in love; and salutations from the secretary general of the United Nations. A team led by Carl Sagan assembled the record as a message to possible extraterrestrial civilizations that might encounter the spacecraft.

"A billion years from now, when everything on Earth we’ve ever made has crumbled into dust, when the continents have changed beyond recognition and our species is unimaginably altered or extinct, the Voyager record will speak for us," wrote Carl Sagan and Ann Druyan in an introduction to a CD version of the record.

Some people note that the chance of aliens finding the Golden Record is fantastically remote. The Voyager probes won’t come within a few light years of another star for some 40,000 years. What are the odds of making contact under such circumstances?  On the other hand, what are the odds of a race of primates evolving to sentience, developing spaceflight, and sending the sound of barking dogs into the cosmos?  Expect the unexpected, indeed.

The Voyagers were built by NASA’s Jet Propulsion Laboratory in Pasadena, Calif., which continues to operate both spacecraft. JPL is a division of the California Institute of Technology in Pasadena. The Voyager missions are a part of the NASA Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission
Directorate.

For more information about the Voyager spacecraft, visit: http://voyager.jpl.nasa.gov and http://www.nasa.gov/voyager.

Like forensic scientists examining fingerprints at a cosmic crime scene, scientists working with data from NASA’s Cassini, Galileo and New Horizons missions have traced telltale ripples in the rings of Saturn and Jupiter back to collisions with cometary fragments dating back more than 10 years ago.

The ripple-producing culprit, in the case of Jupiter, was comet
Shoemaker-Levy 9, whose debris cloud hurtled through the thin Jupiter
ring system during a kamikaze course into the planet in July 1994. 

Scientists attribute Saturn’s ripples to a similar object – likely another cloud of comet debris — plunging through the inner rings in the second half of 1983. The findings are detailed in a pair of papers published online today in the journal Science.

“What’s cool is we’re finding evidence that a planet’s rings can be affected by specific, traceable events that happened in the last 30 years, rather than a hundred million years ago,” said Matthew Hedman, a Cassini imaging team associate, lead author of one of the papers, and a research associate at Cornell University, Ithaca, N.Y.  “The solar system is a much more dynamic place than we gave it credit for.”

From Galileo’s visit to Jupiter, scientists have known since the late 1990s about patchy patterns in the Jovian ring. But the Galileo images were a little fuzzy, and scientists didn’t understand why such patterns would occur. The trail was cold until Cassini entered orbit around Saturn in 2004 and started sending back thousands of images. A 2007 paper by Hedman and colleagues first noted corrugations in Saturn’s innermost ring, dubbed the D ring.

A group including Hedman and Mark Showalter, a Cassini co-investigator based at the SETI Institute in Mountain View, Calif., then realized that the grooves in the D ring appeared to wind together more tightly over time. Playing the process backward, Hedman then demonstrated the pattern originated when something tilted the D ring off its axis by about 100 meters (300 feet) in late 1983. The scientists found the influence of Saturn’s gravity on the tilted area warped the ring into a tightening spiral.

Cassini imaging scientists got another clue when the sun shone directly along Saturn’s equator and lit the rings edge-on in August 2009. The unique lighting conditions highlighted ripples not previously seen in another part of the ring system. Whatever happened in 1983 was not a small, localized event; it was big. The collision had tilted a region more than 19,000 kilometers (12,000 miles) wide, covering part of the D ring and the next outermost ring, called the C ring. Unfortunately spacecraft were not visiting Saturn at that time, and the planet was on the far side of the sun, hidden from telescopes on or orbiting Earth, so whatever happened in 1983 passed unnoticed by astronomers.

Hedman and Showalter, the lead author on the second paper, began to wonder whether the long-forgotten pattern in Jupiter’s ring system might illuminate the mystery. Using Galileo images from 1996 and 2000, Showalter confirmed a similar winding spiral pattern. They applied the same math they had applied to Saturn – but now with Jupiter’s gravitational influence factored in. Unwinding the spiral pinpointed the date when Jupiter’s ring was tilted off its axis: between June and September 1994. Shoemaker-Levy plunged into the Jovian atmosphere during late July 1994. The estimated size of the nucleus was also consistent with the amount of material needed to disturb Jupiter’s ring.

The Galileo images also revealed a second spiral, which was calculated to have originated in 1990. Images taken by New Horizons in 2007, when the spacecraft flew by Jupiter on its way to Pluto, showed two newer ripple patterns, in addition to the fading echo of the Shoemaker-Levy impact.

“We now know that collisions into the rings are very common – a few times per decade for Jupiter and a few times per century for Saturn,” Showalter said. “Now scientists know that the rings record these impacts like grooves in a vinyl record, and we can play back their history later.”

The ripples also give scientists clues to the size of the clouds of cometary debris that hit the rings. In each of these cases, the nuclei of the comets – before they likely broke apart – were a few kilometers wide.

“Finding these fingerprints still in the rings is amazing and helps us better understand impact processes in our solar system,” said Linda Spilker, Cassini project scientist, based at NASA’s Jet Propulsion Laboratory, Pasadena, Calif. “Cassini’s long sojourn around Saturn has helped us tease out subtle clues that tell us about the history of our origins.”

The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the Cassini-Huygens mission for NASA’s Science Mission Directorate, Washington. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging team is based at the Space Science Institute in Boulder, Colo. JPL managed the Galileo mission for NASA, and designed and built the Galileo orbiter. The New Horizons mission is led by Principal Investigator Alan Stern of Southwest Research Institute, Boulder, Colo., and managed by the Johns Hopkins Applied Physics Laboratory, Laurel, Md., for NASA’s Science Mission Directorate.

More information about Cassini can be found at http://www.nasa.gov/cassini

In addition to U.S. Senator Jim Inhofe, others worldwide have been standing strong in rebuke of environmental zealots claiming man causes global warming.  U.K. forecaster Piers Corbyn is an astrophysicist and meteorologist that was first mocked. 

When Corbyn proclaimed early this year that Europe would see the greatest
snow accumulation in 100 years and that America’s Eastern Seaboard would
endure a blizzard of extreme proportions, critics laughed. 

They are not laughing now. 

In a follow-up story, FOX News did an interview with Corbyn where he says, “The science of these so-called scientists (global warming advocates) that you refer to is failed science based on fraudulent data.

“We understand that the sun, solar particles and magnetic effects, control earth’s weather and climate which allow us to predict weather a long time ahead,” Corbyn added.

Click on the link to view the video interview posted on www.TheBlaze.com. 

PASADENA, CALIF. – NASA’s EPOXI mission successfully flew by comet Hartley 2 at about 7 a.m. PDT (10 a.m. EDT) today, and the spacecraft has begun returning images. Hartley 2 is the fifth comet nucleus visited by a spacecraft.

Scientists and mission controllers are currently viewing never-before-seen images of Hartley 2 appearing on their computer terminal screens.

"The mission team and scientists have worked hard for this day," said Tim Larson, EPOXI project manager at NASA’s Jet Propulsion Laboratory, Pasadena, Calif.  "It’s good to see Hartley 2 up close."

Mission navigators are working to determine the spacecraft’s closest approach distance. Preliminary estimates place the spacecraft close to the planned-for 700 kilometers (435 miles). Eight minutes after closest approach, at 6:59:47 a.m. PDT ( 9:59:47 a.m. EDT), the spacecraft’s high-gain antenna was pointed at Earth and began downlinking vital spacecraft health and other engineering data stored aboard the spacecraft’s onboard computer during the encounter. About 20 minutes later, the first images of the encounter made the 37-million-kilometer (23-million-mile) trip from the spacecraft to NASA’s Deep Space Network antennas in Goldstone, Calif., appearing moments later on the mission’s computer screens.

"We are all holding our breath to see what discoveries await us in the observations near closest approach," said EPOXI principal investigator Michael A’Hearn of the University of Maryland, College Park.  

A post-encounter news conference will be held at 1 p.m. PDT (4 p.m. EDT) in the von Karman auditorium at JPL.  It will be carried live on NASA TV.  Downlink and schedule information is online at http://www.nasa.gov/ntv .  The event will also be carried live on http://www.ustream.tv/nasajpl2 .

EPOXI is an extended mission that utilizes the already "in-flight" Deep Impact spacecraft to explore distinct celestial targets of opportunity. The name EPOXI itself is a combination of the names for the two extended mission components: the extrasolar planet observations, called Extrasolar Planet Observations and Characterization (EPOCh), and the flyby of comet Hartley 2, called the Deep Impact Extended Investigation (DIXI). The spacecraft has retained the name "Deep Impact."

JPL manages the EPOXI mission for NASA’s Science Mission Directorate, Washington. The University of Maryland is home to the mission’s principal investigator, Michael A’Hearn. Drake Deming of NASA’s Goddard Space Flight Center, Greenbelt, Md., is the science lead for the mission’s extrasolar planet observations. The spacecraft was built for NASA by Ball Aerospace & Technologies Corp., Boulder, Colo.

For more information about EPOXI visit http://www.nasa.gov/epoxi and http://epoxi.umd.edu/.

PASADENA, Calif. – NASA’s EPOXI mission continues to close in on its target, comet Hartley 2, at a rate of 12.5 kilometers (7.8 miles) per second. On Nov. 4 at about 10:01 a.m. EDT (7:01 a.m. PDT) the spacecraft will make its closest approach to the comet at a distance of about 700 kilometers (434 miles). It will be the fifth time that a comet has been imaged close-up and the first time in history that two comets have been imaged with the same instruments and same spatial resolution.

"Hartley 2 has already put on a great show with more than a few surprises for the mission’s science team," said EPOXI principal investigator Mike A’Hearn from the University of Maryland, College Park. "We expect more of the unexpected during encounter."

Science observations of comet Hartley 2 began on Sept. 5. The imaging campaign is more than a tantalizing tease of things to come. It is providing EPOXI’s science team the best extended view of a comet in history during its pass through the inner solar system. The observations will continue through the encounter phase of the mission.

The hours surrounding comet encounter will be especially challenging for the mission team as they are commanding a recycled spacecraft that was not designed for this comet flyby. The spacecraft was designed and employed successfully for NASA’s Deep Impact encounter of comet Tempel 1 back on July 4, 2005. By recycling Deep Impact’s already built, tested and in-flight spacecraft, the EPOXI mission provided savings on the order of 90% that of a hypothetical mission with similar goals, starting from the ground up.

"If we were starting from scratch we’d probably move some of the spacecraft’s components to different locations," said Tim Larson, project manager for the EPOXI mission from NASA’s Jet Propulsion Laboratory in Pasadena, Calif. "But we’ve developed a creative way to work with what we have.  This spacecraft, and mission team, have logged 3.2 billion miles over the past five years, and we are confident that we have a successful plan in place to give Hartley 2 a thorough look-see."

The mission’s encounter phase begins the evening of Nov. 3, when the spacecraft is about 18 hours from the time of closest approach to the comet’s nucleus. At that time the spacecraft will stop transmitting through its large high-gain antenna and reorient itself so its two visible-light and one infrared imager maintain lock on the comet for the next 24 hours-plus.

"When the encounter phase begins all images the spacecraft takes will be stored aboard its two computers," said Larson. "Soon after we fly past the comet at about 7 a.m. local time, we will be able to re-orient the spacecraft so that we maintain imaging lock on the comet nucleus while pointing our big high gain antenna at Earth."

At that point, the spacecraft will begin beaming down its cache of cometary close-ups while continuing to take new images. It is expected to take several hours for all the images held aboard spacecraft memory to be downlinked.

"We will be waiting," said A’Hearn. "The images at closest approach won’t get to Earth until many hours after the actual encounter due to the way we use memory on the spacecraft.  We will get some early hints at how this nucleus differs from that of comet Tempel 1 based on five images that will get to Earth only about one hour after closest approach."
 
EPOXI is an extended mission that utilizes the already "in-flight" Deep Impact spacecraft to explore distinct celestial targets of opportunity. The name EPOXI itself is a combination of the names for the two extended mission components: the extrasolar planet observations, called Extrasolar Planet Observations and Characterization (EPOCh), and the flyby of comet Hartley 2, called the Deep Impact Extended Investigation (DIXI). The spacecraft will continue to be referred to as "Deep Impact."
 
NASA’s Jet Propulsion Laboratory, Pasadena, Calif., manages the EPOXI mission for NASA’s Science Mission Directorate, Washington. The University of Maryland, College Park, is home to the mission’s principal investigator, Michael A’Hearn. Drake Deming of NASA’s Goddard Space Flight Center, Greenbelt, Md., is the science lead for the mission’s extrasolar planet observations. The spacecraft was built for NASA by Ball Aerospace & Technologies Corp., Boulder, Colo. 
 
For more information about EPOXI visit http://www.nasa.gov/epoxi  or  http://epoxi.umd.edu/.