Voyager Is 30!

rynner2

Great Old One
Joined
Aug 7, 2001
Messages
55,271
Likes
8,908
Points
284
Location
Under the moon
#31
Voyagers ride 'magnetic bubbles'
By Jonathan Amos, Science correspondent, BBC News

Humankind's most distant emissaries are flying through a turbulent sea of magnetism as they seek to break free of our Solar System.
Nasa's Voyager probes, which were launched in 1977, are now approaching the very edge of our Sun's influence, more than 14 billion km from Earth; and they are still returning data.
That information has allowed scientists to build a better picture of what conditions are like in the zone where matter blown out from our star pushes up against interstellar space.

Computer modelling based on the Voyager insights suggests the edge of our Solar System is a froth of activity, like "an agitated jacuzzi", said Eugene Parker from the University of Chicago, US.
Magnetic field lines carried in the "wind" of material coming off our star are breaking and reconnecting.
This process is sculpting the wind into discrete bubbles that are many tens of millions of kilometres wide.

Researchers say this assessment has implications for our understanding of cosmic rays - the storm of high-energy particles that are accelerated in Earth's direction by exploded stars, black holes and other exotic locations in the galaxy.
It is highly likely the mass of individual magnetic structures actually makes the Solar System more porous to cosmic rays.
"It's more like a membrane that is permeable to the galactic cosmic rays, so we expect the galactic cosmic rays to enter and slowly wander through this sea of magnetic bubbles until they can access field lines that connect back to the Sun and quickly escape," explained Professor Parker.

The observation is of interest not just to physicists but also to astronauts, who must protect themselves from the damaging health effects of cosmic rays, and to spacecraft engineers who have to "harden" the electronic circuitry in satellites against the impacts from high-energy particles.
The modelling results will make no difference to their predicament; but it does say something about why the cosmic ray issue takes on such importance.

Researchers confess to being surprised; they thought the outskirts of our solar neighbourhood would be more sedate - that the Sun's field lines would simply turn around and reconnect with the Sun.
"The findings are significant as we will have to change our view on how the Sun interacts with particles, fields and gases from other stars, and this has consequences that reach down to Earth," commented Arik Posner, Nasa's Voyager programme scientist.

It is a demonstration once again of the extraordinary capabilities of the Voyagers, which continue to excite and intrigue more than three decades on from their launch.
Voyager 1 was put in space on 5 September 1977, and its sister spacecraft, Voyager 2, lifted off on 20 August 1977.
The Nasa probes' initial goal was to survey the outer planets Jupiter, Saturn, Uranus and Neptune, a task completed in 1989.
They were then despatched towards deep space, in the general direction of the centre of our Milky Way Galaxy.


[video
David Shukman takes a close look at a replica of the Voyagers]

Sustained by their radioactive power packs, the probes' instruments continue to function well and return data to Earth, although the vast distance between them and controllers in California means a radio message now has a travel time of about 16 hours (in the case of Voyager 1).

The primary task of the spacecraft currently is to define our Sun's limits - to map the extent of its heliosphere, as scientists call it.
Our star blows out huge volumes of excited particles. This wind, laced with a magnetic field, travels out at high speed until it crashes into the interstellar magnetic field, at which point the Sun's outpouring abruptly slows and begins to move sideways.

It is at this boundary - the heliopause - where the Voyagers find themselves today, and where the Sun's magnetic field lines are snapping and reconnecting to produce the structures reported by scientists.


No-one is quite sure where our Solar System ends and interstellar space begins, but the expectation is that the probes will break through soon - perhaps in the next three or four years.

http://www.bbc.co.uk/news/science-environment-13715764
 

rynner2

Great Old One
Joined
Aug 7, 2001
Messages
55,271
Likes
8,908
Points
284
Location
Under the moon
#32
Journey into the uncharted voids of the Milky Way
Nasa's Voyager 1 spacecraft is about to become the first man-made object to leave the Solar System
Steve Connor Wednesday 07 December 2011

After a voyage lasting more than 34 years, a spacecraft that has travelled further than any man-made object is on the verge of leaving the Solar System and entering the mysterious region of interstellar space, where nothing terrestrial has gone before.

[graphic ]

Scientists at the US National Aeronautics and Space Administration (Nasa) said that the Voyager 1 space probe, which has travelled about 11 billion miles since its launch in 1977, has entered the cosmic equivalent of the doldrums, where the high-speed solar winds die down at the very edge of the Solar System.

Voyager 1, launched within weeks of its twin probe,Voyager 2, was originally designed to explore Jupiter and Saturn. After making a string of important observations, such as active volcanoes on Jupiter's moon Io and the intricacies of Saturn's rings, the mission was extended. Voyager 2 went on to explore the faraway planets of Uranus and Neptune.

However, long after the official planetary missions ended, both spacecraft continued to plough through the farthest regions of the Solar System, while maintaining radio contact with mission control through its Deep Space Network.

Nasa expects that within the next few months – or possibly years if margins of error are taken into account – Voyager 1 will finally leave the Solar System for good and begin its journey through the vast void of interstellar space that comprises most of the Milky Way galaxy. Voyager 2 – travelling not far behind – will follow suit.

Scientists at Nasa said that over the past year, Voyager 1 had entered a kind of "cosmic purgatory" where the wind of electrically charged particles streaming from the Sun has calmed.

Both spacecraft are now in a region known as the "heliosheath", the outermost layer of the Solar System, where the solar wind, which can travel 16 miles per second, is being slowed down by the rising pressure of interstellar gas. Nasa scientists believe this indicates the imminent entry of Voyager 1 into the interstellar region, which is dominated by another kind of magnetic wind coming from a different direction of deep space.

"Voyager tells us now that we're in a stagnation region in the outermost layer of the 'bubble' around our Solar System. Voyager is showing that what is outside is pushing back. We shouldn't have long to wait to find out what the space between the stars is really like," said Ed Stone, Voyager project scientist at the California Institute of Technology in Pasadena.

Nasa changed the orientation of Voyager 1 four times this year to see whether the solar wind and magnetic field lines had switched direction. Data released at the American Geophysical Union meeting in San Francisco shows the magnetic field lines have not changed, indicating that Voyager 1 is still just within the "heliosphere", the magnetic bubble of charged particles created by the Sun.

"We have seen the same east-west direction of the magnetic field since we launched. That's the solar magnetic field. Once we leave the heliosphere we will enter the magnetic field of the galaxy and all the data to date suggest that this field is orientated more north-south," Dr Stone told the meeting.

...

http://www.independent.co.uk/news/scien ... 73178.html
 
Joined
Aug 19, 2003
Messages
47,870
Likes
19,194
Points
284
Location
Eblana
#33
Particles point way for Nasa's Voyager
http://www.bbc.co.uk/news/science-environment-18458478
By Jonathan Amos
Science correspondent, BBC News

The Voyagers are moving in the general direction of the centre of our Milky Way Galaxy

Related Stories

Dead stars 'to guide spacecraft'
To boldly go beyond the Solar System
Voyagers ride 'magnetic bubbles'

Scientists working on Voyager 1 are receiving further data suggesting the probe is close to crossing into interstellar space.

The Nasa mission, which launched from Earth in 1977, could leave our Solar System at any time.

It is now detecting a sharp rise in the number of high-energy particles hitting it from distant exploded stars.

The observation was predicted, and is another indication that Voyager will soon reach its historic goal.

"The laws of physics say that someday Voyager will become the first human-made object to enter interstellar space, but we still do not know exactly when that someday will be," Ed Stone, the Voyager project scientist at the California Institute of Technology in Pasadena, said in a Nasa statement.

"The latest data indicate that we are clearly in a new region where things are changing more quickly. It is very exciting. We are approaching the Solar System's frontier."

Voyager 1 is travelling at about 17 km per second (38,000 mph), and is almost 18 billion km (11 billion miles) from Earth.

The vast separation means a signal from the probe takes more than 16 and a half hours to arrive at Nasa's receiving network.

In the last three years, Voyager has seen a steady increase in the number of cosmic rays entering its two high-energy telescopes, but in the past month the counts have jumped markedly.

Continue reading the main story
Nasa's Voyager probes

Voyager 2 launched on 20 August 1977; Voyager 1 lifted off on 5 September the same year
Their official missions were to study Jupiter and Saturn, but the probes were able to continue on
The Voyager 1 probe is now the furthest human-built object from Earth
Both probes carry discs with recordings designed to portray the diversity of culture on Earth
To boldly go beyond the Solar System
The cosmic ray count is one of three indicators Nasa is using to determine when the probe has moved to interstellar space.

The second is a change in the intensity of the energetic particles Voyager detects around it coming from our Sun.

The number of these hits is declining, but not dramatically so, which should happen when Voyager leaves the region of space dominated by our star.

A third indicator will be a change in the direction of the magnetic field lines. These are expected to undergo a major reorientation when Voyager breaks into interstellar space.

Voyager 1 was launched on 5 September 1977, and its sister spacecraft, Voyager 2, on 20 August 1977.

The probes' initial goal was to survey the outer planets Jupiter, Saturn, Uranus and Neptune, a task they completed in 1989.

They were then despatched towards deep space, in the general direction of the centre of our Milky Way Galaxy.

Their plutonium power sources will stop generating electricity in about 10-15 years, at which point their instruments and transmitters will die.

The Voyagers will then become "silent ambassadors" from Earth as they move through the Milky Way.

Voyager 1 is on course to approach a star called AC +793888, but it will only get to within two light-years of it.

Voyager 2 was launched before Voyager 1 and was put on a slower path to interstellar space. It is currently 14.7 billion km from Earth.

It is hurtling towards a star named Ross 248, but, again, even at its closest, it will still be a whole light-year away.


The domain of the Sun's influence is called the heliosphere: The Voyagers are approaching the edge of this enormous balloon of charged particles thrown out into space by our star

[email protected]. and follow me on Twitter
 
Joined
Aug 19, 2003
Messages
47,870
Likes
19,194
Points
284
Location
Eblana
#34
Voyager approaches the edge of the abyss.

Voyager’s long goodbye
NASA probes find surprises at the edge of the Solar System.
http://www.nature.com/news/voyager-s-lo ... ye-1.11348
Ron Cowen
05 September 2012

Are we there yet? Ed Stone, the project scientist for NASA’s two Voyager spacecraft, wants to know. Since their launch in 1977, the probes have ventured billions of kilo­metres beyond the outer planets. Now, Stone and his colleagues are looking for signs that Voyager 1 may finally be nearing the edge of the Solar System — where the heliosphere, the bubble of electrically charged particles blown outwards by the Sun, gives way to interstellar space (see ‘Edging into the unknown’).

Detecting and characterizing this threshold — called the heliopause — would be the ultimate bonus for a probe that logged its 35th year in space on 5 September. When Voyager 1 set out, says Stone, a physicist at the California Institute of Technology in Pasadena, who has coordinated the mission since the probes launched, “the space age was only 20 years old and there was no evidence that any spacecraft could travel this long and this far from the Sun”.

The extraordinarily long-lived Voyager 1 began detecting hints of a boundary region eight years ago. But exiting the Solar System is proving to be a longer and more complicated affair than Stone and his colleagues had anticipated. By the time Voyager 1 is well and truly out, it may have transformed researchers’ ideas about the Solar System’s invisible edge.

In the latest twist in the story, the craft seems to be traversing an unexpected ‘dead zone’. This week, Robert Decker, a space scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, and his colleagues report1 in Nature that at Voyager 1’s current location, some 121.6 astronomical units (18.2 billion kilometres) from the Sun, the average velocity of solar particles has dropped to nearly zero. (Voyager 2, which is about 3 billion kilometres closer to the Sun and moving in a different direction, has yet to detect the same reduction in velocity.)

Decker’s team first reported2 the change last year, when it had measurements of the particles’ velocity only in the radial direction, outwards from the Sun. At the time, the team thought that the change was a sign that the craft was nearing the heliopause, where solar particles are expected to collide with powerful winds generated by supernovae that exploded some 5 million to 10 million years ago. The collision would force the solar particles to stop moving outwards and push them sideways, like a stream of water hitting a solid surface.

To test the idea, engineers commanded Voyager 1 to roll on its side seven times, so that its instruments could record particle velocities along a line perpendicular to its course. Given that sending a command to Voyager 1 now takes 17 hours, and that the spacecraft’s transmitter runs at 23 watts — about as powerful as a refrigerator light bulb — such communication is a feat in itself. The researchers were astonished to find that the particles had zero velocity in this polar direction, too — indicating that they were almost stationary rather than being buffeted by stellar winds. That cannot happen at the heliopause, says Decker. “We therefore conclude … that Voyager 1 is not at the present time close to the heliopause, at least in the form that it has been envisioned,” the team writes1.

Voyager 1 was launched in 1977. Four of its original instruments (labelled in yellow) are still returning data on conditions at the edge of the Solar System.
NASA/JPL-CALTECH

Decker and his colleagues now think that since 2010, when the craft first recorded a velocity drop, it has been in an antechamber to the heliopause, at least 1 billion kilometres thick. Why the particles are becalmed remains a mystery, says Stamatios Krimigis, a space scientist at Johns Hopkins and a co-author of the paper. This leaves theorists in a bind. “There no longer exists any guidance on what constitutes getting out of the Solar System and into the Galaxy,” says Krimigis.

Gary Zank, a theoretical physicist at the University of Alabama in Huntsville, disagrees. “I don’t regard the paper as forcing us to revise our models,” he says. His team and others theorize3 that a magnetic wall in the outer heliosphere, caused by a pile-up of magnetic field lines, could slow down the flow of charged particles and account for the near-zero velocities recorded by Voyager 1.

Although the craft has not yet made it to the helio­pause, the boundary may be within reach. This May, Voyager 1 recorded unprecedented bursts of cosmic rays — highly energized protons and atomic nuclei — coming from outside the Solar System. The spikes returned in July, this time along with a drop in the incidence of lower-energy cosmic rays thought to be accelerated in the Solar System. The changes suggest that Voyager 1 is nearing the fringe of the Solar System, and could cross the heliopause by the end of the year, says Krimigis. But, he adds, “nature seems to be much more imaginative than we are, so I could be quite wrong”.

Indeed, David McComas, a physicist at the Southwest Research Institute in San Antonio, Texas, and Nathan Schwadron, a plasma physicist at the University of New Hampshire in Durham, suggest an alternative explanation. In an article in press in The Astrophysical Journal, they propose that Voyager 1 is in a region where magnetic field lines running through the outer heliosphere link up with the magnetic field of the rest of the Galaxy. Here the field would create a conduit for galactic cosmic rays, causing the spikes in detection. Cosmic rays accelerated within the heliosphere would tend to move along other field lines and be less likely to get to Voyager. If this model is correct, say McComas and Schwadron, the heliopause may still be years away.

“There no longer exists any guidance on what constitutes getting out of the Solar System.”

When Voyager 1 does leave the Solar System, it may meet further surprises. Researchers have long assumed that a bow shock lies outside the heliopause. Similar to the shock wave around a supersonic aircraft, the bow shock is thought to form as the Solar System ploughs through the interstellar medium, forcing the local ionized gas to change density abruptly and discontinuously. But in May, McComas and his colleagues reported4 that data from NASA’s Interstellar Boundary Explorer (IBEX) mission cast doubt on this picture. From Earth orbit, IBEX probes the interstellar medium by detecting electrically neutral atoms that slip into the Solar System through the heliopause. Its measurements suggest that the Sun and planets are moving through the interstellar medium about 12% slower than previously calculated — too slow to generate a bow shock.

None of this uncertainty bothers Stone, who expects both Voyagers to cross the heliopause well before 2025, when the craft are due to go silent as the plutonium isotopes that supply their power run out. On the contrary, Stone adds, he is pleased that the one-way journey has taken so many unexpected turns. “One thing Voyager has taught us is to be prepared to be surprised.”

Nature 489, 20–21 (06 September 2012) doi:10.1038/489020a

See Editorial page 6

References

Decker, R. B., Krimigis, S. M., Roelof, E. C. & Hill, M. E. Nature 489, 124–127 (2012).
Article
Show context

Krimigis, S. M., Roelof, E. C., Decker, R. B. & Hill, M. E. Nature 474, 359–361 (2011).
ArticlePubMedISIChemPort
Show context

Zank, G. P. Space Sci. Rev. 89, 413–688 (1999).
ArticleISI
Show context

McComas, D. J. et al. Science 336, 1291–1293 (2012).
ArticlePubMedISIChemPort
Show context

Related stories and links

From nature.com

Moonlight drive
05 September 2012

A whiff of interstellar cloud
01 February 2012

Voyager at the edge
15 June 2011

IBEX spacecraft set to map the final frontier
17 October 2008

Scientific exploration: What a long, strange trip it's been
02 July 2008

From elsewhere

Voyager
IBEX
 

rynner2

Great Old One
Joined
Aug 7, 2001
Messages
55,271
Likes
8,908
Points
284
Location
Under the moon
#35
Voyager: the space explorers that are still boldly going to the stars
Nasa's two Voyager ships have reached the edge of the solar system – and their incredible 35-year journey is far from over
Email Dallas Campbell and Christopher Riley
The Observer, Sunday 21 October 2012

The year 1977 was an important one for music. Fleetwood Mac's Rumours and the Sex Pistols' Never Mind the Bollocks were released. Elvis left the building for the last time, dying at the age of only 42. But amid all this rock'n'roll history another less celebrated but far more significant album was quietly being made.

Fashioned from copper rather than vinyl, and plated with gold for longevity, The Sounds Of Earth was compiled by the American astronomer Carl Sagan. It was a broader range of music than most of the other albums released that year, aiming to encapsulate 5,000 years of human culture; from an Australian Aborigine song and an Indian raga to Azerbaijani bagpipes, bamboo flutes, Bach, Beethoven and Chuck Berry.

Like any compilation album, each piece was carefully selected and its merit, to make the cut, hotly debated. But unlike most other records, only two copies were made. They were placed inside their aluminium album covers, complete with artwork in the form of a "clear", universally understandable, pictorial depiction of what they were and instructions for how to play them. A stylus was also included, to help any creatures that might chance upon them in the future to hear the music and other recordings. In a scene that would not have been out of place in Ridley Scott's recent Prometheus, they were then carefully bolted to the outside of the two Voyager spacecraft, by the last human beings ever to touch them.

The records sit on one face of each craft's 10-sided "chassis" or bus, above which sits the large, white 3.7-metre wide communications dish, which dominates the structure. Protruding, insect-like, from the craft are "limbs" and antennae. The radioisotope thermoelectric generators, which power the Voyagers in the darkest reaches of the outer solar system, stretch out to on one side, just below a proboscis-like, 13m-long magnetometer boom. Across the other side of the craft, another broad arm juts out. It carries Voyager's "eyes" – an array of cameras, spectrometers, particle detectors and other equipment.

The challenge for Nasa's Jet Propulsion Lab, which designed and constructed the Voyagers, was to build a craft that could survive in space for years. In the early 1970s, when the JPL team began the project, they'd never built a craft rated for longer than a few months of interplanetary travel. It was a big jump to create something that would reach the outer planets, and perhaps even farther.

"At that point in time, that was a mind-blowing thought," says Voyager systems engineer John Casani. "How you build a spacecraft that can survive failures and still keep on chugging. We thought we could do it. Nobody else did!"

...

It's not just the Voyagers that are ageing. Everyone on the team has lived out their lives against the backdrop of their mission. "When I started on Voyager my two daughters were young," says Ed Stone, who has been on board since day one. "By the time they were in college we had passed Saturn and were on our way to Uranus. They got married and the Voyagers just kept going, and we had grandchildren and Voyager just kept going and our grandchildren are now aware of what's happening to the Voyagers just like our children were."

etc...

Campbell and Riley's documentary, Voyager – to the Final Frontier, is on BBC4 at 9pm on 24 October. Hear the Voyager golden discs' playlist at goldenrecord.org

http://www.guardian.co.uk/science/2012/ ... lar-system
 

Kondoru

Antediluvian
Joined
Dec 5, 2003
Messages
5,378
Likes
36
Points
114
#36
Its a beautiful article and for once the comments are generaly positive and informed.
 

rynner2

Great Old One
Joined
Aug 7, 2001
Messages
55,271
Likes
8,908
Points
284
Location
Under the moon
#37
The maths that made Voyager possible
By Christopher Riley and Dallas Campbell, BBC Four

[video: In 1961, mathematics graduate Michael Minovitch decided to take on the hardest problem in celestial mechanics - the "three body problem".
Continue reading the main story]

Nasa's Voyager spacecraft have enthralled everyone with their exploits at the edge of the Solar System, but their launch in 1977 was only possible because of some clever maths and the persistence of a PhD student who worked out how to slingshot probes into deep space.

On the 3 October, 1942, the nose cone of an early V2 test rocket soared high above the north German coast before falling back to a crash-landing in the Baltic Sea.
For the first time in history, an object built by humans had crossed the invisible Karman line, which marks the edge of space.
Astonishingly, within 70 years - just one human lifespan - we'd hurled another spacecraft right to the edge of the Solar System.

Today, 35 years after leaving Earth, Voyager 1 is 18.4 billion km (11.4 billion miles) from Earth and about to cross over the boundary marking the extent of the Sun's influence, where the solar wind meets interstellar space.
Sometime in the next five years, it will likely break through this so called "bowshock" and head out into the galaxy beyond. Its twin, Voyager 2, having flown past all the outer giant planets, should pass over into interstellar [space] not long after.

It's easy to take this monumental achievement for granted, but the gateway to the outer Solar System remained shut for the first 20 years of the space age.
In 1957, as Sputnik 1 became the first engineered object to orbit our home planet, mission planners started to look towards other worlds to propel their probes.
Spacecraft were quickly dispatched to the Moon, Venus and Mars. But there was one major limiting factor to reaching more distant destinations.

For a voyage to the outer planets, you must escape the gravitational pull of the Sun, and that demands a very large rocket indeed. And given what an "uphill" gravitational struggle it would be to reach them, such a journey to the furthest planet - Neptune, more than four billion km (2.5 billion miles) away - could easily take 30 or 40 years.

At the time, Nasa couldn't guarantee a spacecraft for more than a few months of operational life, and so the outer planets were considered out of reach.
That was until a 25-year-old mathematics graduate called Michael Minovitch came along in 1961.
Excited by UCLA's new IBM 7090 computer, the fastest on Earth at the time, Minovitch decided to take on the hardest problem in celestial mechanics: the "three body problem".

The three bodies it refers to are the Sun, a planet and a third object such as an asteroid or comet all travelling through space with their gravities acting on each other. The problem is predicting exactly how the gravity of the Sun and the planet will influence the third object's trajectory.

Astronomers had been pondering the three-body problem for at least 300 years, ever since they'd started plotting the path that comets took as they fell through the inner Solar System towards the Sun.
Undeterred by the fact that some of the finest minds in history, including Isaac Newton hadn't solved the three-body problem, Minovitch became focused on cracking it. He intended to use the IBM 7090 computer to home in on a solution using a method of iteration.

In his spare time, whilst studying for his PhD during the summer of 1961, he set about coding a series of equations to apply to the problem.
Feeding data on planetary orbits into his model, Minovitch had made progress by the autumn, but was anxious to check his data. So in the summer of the following year, during an internship at Nasa's Jet Propulsion Lab he persuaded his boss to give him more accurate data on planetary positions to re-test his model.
To his delight, he ran the simulations again and found his solution still worked. What he had achieved made possible an extraordinary breakthrough in spacecraft propulsion.

Minovitch had shown that as a craft flew close to a planet orbiting the Sun, it would steal some of the planet's orbital speed, and be accelerated away from the Sun. Such acceleration, without using a single drop of rocket propellant seemed too good to be true, and Minovitch's critics were quick to try to discredit him.

Without funds for further computer time, and in a bid to persuade Nasa to embrace his discovery, he drew up by hand hundreds of theoretical mission trajectories to the outer planets. Among them was one very special flight path that would become the Voyagers' trajectory.

But in 1962 the Jet Propulsion Lab was preoccupied with supporting Project Apollo, and no-one spotted Minovitch's breakthrough.
It would take another summer intern called Gary Flandro to identify the opportunity.

A spacecraft engineer, grounded in the hard realities of spaceflight, Flandro knew that any mission to the outer planets would have to be flown as fast as possible, otherwise the craft might not last long enough to reach its destination.

So in the summer of 1965, he began to look at whether the solution to the three-body problem could be put to practical use in exploring the outer planets. He started by drawing graphs of where these planets were going to be in the coming years.
And to his surprise, the plots revealed that Jupiter, Saturn, Uranus and Neptune would all be on the same side of the Solar System in the late 1970s.

Using a solution to the three-body problem, a single mission, launching from Earth in 1977, could sling a spacecraft past all four planets within 12 years. Such an opportunity would not present itself again for another 176 years.

With further lobbying from Minovitch and high level intervention from Maxwell Hunter, who advised the president on US space policy, Nasa eventually embraced Minovitch's slingshot propulsion and Flandro's idea for a "grand tour" of the planets.

Initially named "Mariner-Jupiter-Saturn", or MJS, funding to build two spacecraft was released in the early 1970s. The twin craft would eventually become known as the Voyagers.
To reach Neptune they would have to last for over a decade in space, operating in the darkest reaches of the Solar System billions of km from the Sun.

They would require radiation-hardened electronics to survive their encounters with the magnetosphere of Jupiter, and an artificial intelligence autonomous enough to make independent decisions when too far away from Earth for help.

Although still lacking funding to extend its mission beyond Saturn, Nasa's optimistic engineers loaded enough control propellant on board to keep the probes' dishes orientated towards the Earth for decades after passing Saturn.
They'd also built the Voyager power supply system to last until at least the year 2020. But most visionary of all, they'd included five experiments on board that were capable of analyzing space beyond the Solar System.

In 1977, as the duo launched from Earth, no-one dared imagine that they would survive long enough to make such measurements. But in 2012, they're still going strong - their pitifully weak signals just a billionth of a billionth of a billionth of a watt of power by the time they reach the Earth. New discoveries are still being made.

Today, in a darkened lecture theatre at JPL - named after the same Theodore von Karman whose boundary to space our machines first crossed 70 years ago - sits a model of the Voyagers.
These great machines are now carrying our spirit of exploration across a boundary the Hungarian-American engineer could only dream of - into interstellar space.

Voyager: To The Final Frontier will be broadcast on BBC Four on Wednesday 24 October, 2012. It is produced and directed by Christopher Riley and presented by Dallas Campbell.

http://www.bbc.co.uk/news/science-environment-20033940
 

Novena

Offanonagin
Joined
Nov 23, 2002
Messages
1,020
Likes
417
Points
114
#38
Kondoru said:
Its a beautiful article and for once the comments are generaly positive and informed.
Indeed. It made me quite wistful and teary-eyed to think of them trundling into space forever. What things they'll see after we lose contact with them... :cry:
 

GNC

King-Sized Canary
Joined
Aug 25, 2001
Messages
26,875
Likes
11,376
Points
284
#39
They will be back to destroy the Earth in three hundred years or so, but fortunately Captain Kirk will be there to deal with them.
 

rynner2

Great Old One
Joined
Aug 7, 2001
Messages
55,271
Likes
8,908
Points
284
Location
Under the moon
#40
Voyager 1 on the brink of leaving the solar system
Nasa's Voyager 1 spacecraft has entered a new region at the edge of the solar system and is close to becoming the first spaceship to journey into interstellar space.
11:34PM GMT 03 Dec 2012

Scientists have dubbed this previously unknown region the "magnetic highway" and it's the last stop before interstellar space, or the space between stars.
The region allows charged particles from inside the heliophere to flow outward and particles from the galaxy outside to come in.

The news of Voyager's progress was presented on Monday at a meeting of the American Geophysical Union meeting in San Francisco.
"We do believe this may be the very last layer between us and interstellar space," MSNBC reported Edward Stone, a Voyager project scientist, as saying.
"This region was not anticipated, was not predicted."

It could take up to two years for Voyager to exit the solar system, he said.

Voyager 1 and its twin Voyager 2 launched 35 years ago on a tour of the outer planets. After they completed the tour, both spacecraft continued to hurtle toward the fringes of the solar system.

Mission chief scientist Ed Stone says it's unknown when Voyager 1 will finally break through to interstellar space. Once that happens, it'll be the first man-made object to leave the solar system.

Source: AP

http://www.telegraph.co.uk/science/spac ... ystem.html
 

rynner2

Great Old One
Joined
Aug 7, 2001
Messages
55,271
Likes
8,908
Points
284
Location
Under the moon
#41
Voyager Solar System 'exit' debated
By Jonathan Amos, Science correspondent, BBC News

The possibility that the Voyager-1 spacecraft may have left the Solar System is being hotly debated.
Launched in September 1977, the probe was sent initially to study the outer planets, but then just kept on going.

Researchers studying its data say the craft appears now to be in a realm of space beyond the influence of our Sun.
But the US space agency (Nasa), which manages Voyager, says that it regards the probe as still being inside the Solar System.

The mission is currently moving more than 18 billion km from Earth, or 123 times the distance between our planet and the Sun.

The latest research is published online in the journal Geophysical Research Letters (GRL).
It concerns data the spacecraft has been gathering about changes in its environment which for some time now have suggested it is about to cross over the Solar System's border - the so-called heliopause.

It has been detecting a rise in the number of high-energy particles, or cosmic rays, coming towards it from interstellar space, while at the same time recording a decline in the intensity of energetic particles coming from behind, from our Sun.

A big change occurred on 25 August last year, which the GRL paper's authors say was like a "heliocliff".
"Within just a few days, the heliospheric intensity of trapped radiation decreased, and the cosmic ray intensity went up as you would expect if it exited the heliosphere," explained Prof Bill Webber from New Mexico State University in Las Cruces.

Nasa funded the study but said any assessment that Voyager might be in interstellar space did not reflect the view of everyone working on the project, and Prof Weber acknowledges there is an on-going debate about the probe's status.
Many researchers would like a long period with the data all pointing in one direction before calling the exit definitive.

"It's outside the normal heliosphere, I would say that," Prof Webber said in a release from the American Geophysical Union, publishers of GRL.
"We're in a new region. And everything we're measuring is different and exciting."

The Voyager project scientist at Nasa's Jet Propulsion Laboratory, Ed Stone, said he wanted to see a reorientation of the magnetic fields around the probe before declaring it to be in interstellar space. This was a "critical marker", he added. "…that change of direction has not yet been observed."

Voyager-1 was launched on 5 September 1977, and its sister spacecraft, Voyager-2, on 20 August 1977.
The probes' initial goal was to survey the outer planets Jupiter, Saturn, Uranus and Neptune - a task they completed in 1989.

They were then despatched towards deep space, in the general direction of the centre of our Milky Way Galaxy.
Their plutonium power sources will stop generating electricity in about 10-15 years, at which point their instruments and transmitters will die.

Voyager-1 is on course to approach a star called AC +793888, but it will only get to within two light-years of it and it will be tens of thousands of years before it does so.

http://www.bbc.co.uk/news/science-environment-21866532

Unusually, the Beeb adds: This page was updated following clarifications issued by both the AGU, the GRL publishers, and Nasa.
 
Joined
Dec 11, 2009
Messages
13
Likes
2
Points
9
#42
Hi there. I am a fan of the Voyager probes, and as there are a couple of questions on this thread which have not been replied-to, I thought I'd stick my oar in, if I may.

Ronson8 said:
It's fascinating to think a man made object is heading out to interstellar space, how long I wonder will it take to travel one light year?
Voyager 1's current velocity is approximately 17.034 kilometers per second away from the Sun. Just supposing it carried on at that speed, it would take about 17,600 years to chalk up one light year. Voyager 2, travelling more slowly, would take approx. 19,440 years to chalk up one light year if it continued at its present speed.

Unfortunately the probes are gradually slowing down as they climb out of the Sun's mighty gravity well, so to get an exact answer to this question, you would need to factor-in the rate of slowdown, which makes it a bit more complicated. However, the above gives you a good idea, based on the current velocity.

skinny said:
Can you tell us if there's a destination? A direction? I could find out linkwise, but I reckon you'd know. so..
The direction of the Voyager probes into interstellar space is random and unplanned from NASA's point of view. Voyager 1 visited Jupiter and Saturn, and Voyager 2, uniquely and astonishingly, visited 4 different planets, namely Jupiter, Saturn, Uranus and Neptune.

Once the probes had finished their magnificently successful mission to visit the above planets, whilst receiving a gravitational "kick" each time they did a flyby (see Rynner's post above on the slingshot effect) then they simply carried on with their current trajectory. However, for the record, to answer your question, the current position of the probes in the sky is as follows:

Voyager 1: Right Ascension 17h 11m, Declination 12 degrees 25 mins.

Voyager 2: Right Ascension 19h 57m, Declination -56 degrees 11 mins.

If this data means nothing to you, imagine if we could see the Voyager probes shining like a bright star. Voyager 1 would be shining in the constellation of Ophiuchus, and Voyager 2 would be shining in the constellation of Telescopium.

Voyager 1 is climbing out above the plane of the ecliptic, whereas Voyager 2 is diving down below the ecliptic. They are headed in rather different, but not opposite, directions.

Another little snippet for you - where Voyager 1 is, right now, the Sun is approximately 12,500 times less bright than we see it on a hot summer's day, in a clear sky.

Just my tuppence worth.

Bill.
 

The late Pete Younger

Venerable and Missed
Joined
Jul 31, 2001
Messages
5,919
Likes
124
Points
129
#43
One day when we discover warp drive, as I'm sure we will one day despite what present day science tells us, both voyagers will brought back to Earth and put on show in a museum.
 

rynner2

Great Old One
Joined
Aug 7, 2001
Messages
55,271
Likes
8,908
Points
284
Location
Under the moon
#44
Ronson8 said:
One day when we discover warp drive, as I'm sure we will one day despite what present day science tells us, both voyagers will brought back to Earth and put on show in a museum.
..unless some other race with a warp drive gets them first! ;)
 

Bigphoot2

Not sprouts! I hate sprouts.
Joined
Jul 30, 2005
Messages
5,939
Likes
14,094
Points
294
#45
Ronson8 said:
One day when we discover warp drive, as I'm sure we will one day despite what present day science tells us, both voyagers will brought back to Earth and put on show in a museum.
Unless one comes back by itself, looking for its creator :)
 

rynner2

Great Old One
Joined
Aug 7, 2001
Messages
55,271
Likes
8,908
Points
284
Location
Under the moon
#48
Voyager surfs Solar System's edge
By Jonathan Amos, Science correspondent, BBC News

"It could be any day, but it could also be several more years."
Ed Stone cannot say when the Voyager-1 spacecraft will leave the Solar System, but he believes the moment is close.

The latest data from this extraordinary probe, reported in this week's Science journal, suggests it is surfing right on the very edge of our Sun's domain.
The particles streaming away from our star have reduced to a trickle at its present location, 18.5 billion km from Earth.
Particles flying towards it from interstellar space, by contrast, have jumped markedly in the past year.
It all points to an imminent departure, which would make Voyager the first man-made object to cross into the space between the stars.

"It's hard to imagine there's another layer between the one we're in and the outside," Dr Stone told BBC News. "Topologically, it makes sense that this is the outermost layer. The only question is: how thick is it?"

Launched way back in 1977, the probe has now travelled so far from home that its constant chatter of data takes 17 hours to arrive at the US space agency's receiving network. And chatter, it does.
Voyager's instruments are busy sampling the far-flung environment. This has allowed Dr Stone and colleagues to map the shape and reach of the heliosphere - the giant bubble of charged particles blown off from our Sun.

In 2004, it reached a turbulent region referred to as the heliosheath, where particles bounced around in all directions.
It was expected this would be the final stage before the leap to interstellar space. But, as has been the case throughout this 35-year mission, Voyager threw up yet another surprise.

Last year, it detected what appears to be a discrete boundary layer that Ed Stone's team call the "heliosheath depletion region" in Friday's three Science papers.
It is a kind of magnetic highway where energetic particles on the inside can get out easily, and the galactic cosmic ray particles on the outside can zoom in.

"It is where the Sun's magnetic field has piled up, compressed up against itself. It has also doubled in strength. It's smoother than anything we've ever seen with Voyager," Dr Stone explained.
The team is now watching the direction of the field lines very carefully. Currently, they orientate east-west, wound into a spiral by the rotating Sun. But when Voyager finally breaks through into interstellar space, they are expected to shift dramatically, running north-south.

This is an acid test for Dr Stone. Although some might argue the particle data is evidence of Voyager being outside the Solar System, the project leader believes the probe cannot truly be said to be beyond the Sun's domain until it has also escaped our star's magnetic influence.

But do not expect an immediate, definitive announcement from Nasa that Voyager is in interstellar space when the magnetic signal does switch.
Instead, the instrument scientists will sit and listen to the probe's chatter, perhaps for several months. They will want to be absolutely sure Voyager has broken through the so-called heliopause.

Like the surfer who rides the front of a breaking wave, battling the foam, Voyager will take some time to move completely clear of everything behind.
"The edge may be somewhat turbulent. We just don't know," Dr Stone told BBC News. "This is exploration after all, and we will find out how Nature makes this interface. But it will be moving because the Sun does 'breathe' in and out."

Voyager 1 is on course to approach a star called AC +793888, but it will only get to within two light-years of it and take some 40,000 years to make the passage.

Voyager 2, which was launched a few weeks before Voyager 1, is on a slightly slower path to interstellar space and is probably a few years from seeing the heliosheath depletion region.
Both probes have sufficient power in their plutonium "batteries" to keep working into the next decade.

http://www.bbc.co.uk/news/science-environment-23075332
 

skinny

Antediluvian
Joined
May 30, 2010
Messages
6,885
Likes
6,254
Points
284
#49
rynner2 said:
Voyager surfs Solar System's edge

Voyager 1 is on course to approach a star called AC +793888, but it will only get to within two light-years of it and take some 40,000 years to make the passage.

http://www.bbc.co.uk/news/science-environment-23075332
I can't wait. :lol:

This voyage stimulates the imagination. Scripting here. Imagine Dr Stone's surprise when Voyager reported back that it had hit a stationary object just outside the heliopause. "Watson... Get me the President." Cue dramatic score - Floyd's Echoes would do nicely.
 

rynner2

Great Old One
Joined
Aug 7, 2001
Messages
55,271
Likes
8,908
Points
284
Location
Under the moon
#50
skinny said:
Scripting here. Imagine Dr Stone's surprise when Voyager reported back that it had hit a stationary object just outside the heliopause. "Watson... Get me the President." Cue dramatic score - Floyd's Echoes would do nicely.
Which raises the question, 'Stationary relative to what?' ;)

If it's stationary with respect to the Sun, then Voyager would slam into it at a velocity of just over 17km per sec (according to Big Bill Robins, above), or over 60,000 kph. I doubt that it would send any signals after that! :twisted:
 

skinny

Antediluvian
Joined
May 30, 2010
Messages
6,885
Likes
6,254
Points
284
#51
She's out! ... maybe.
NASA's Voyager 1 is first spacecraft to leave solar system, scientists say


By North America correspondent Michael Vincent, wires

Updated 57 minutes ago


The Voyager 1 spacecraft has become the first man-made object to leave the solar system, scientists say.

NASA says the spacecraft left the solar system last year, but its scientists have only just been able to measure electron plasma oscillations to confirm the exit.

"This is the first time that humanity has been able to step outside of the cradle of the solar system to explore the larger galaxy," said Marc Swisdak, an astrophysicist at the University of Maryland.

The unmanned probe was launched in 1977 to study Jupiter and Saturn but has continued for 19 billion kilometres and is now exploring the galaxy.

It is carrying a golden disc with spoken greetings, earth sounds and a collection of music in case it is found by intelligent life forms.

The precise position of Voyager has been fiercely debated in the past year.

This is because scientists have not known exactly what it would look like when the spacecraft crossed the boundary of the solar system and the tool on board that was designed to detect the change does not work.

However, US space agency scientists now agree Voyager is officially outside the protective bubble, known as the heliosphere, that extends at least 13 billion km beyond all the planets in our solar system, and has entered interstellar space.

"Voyager has boldly gone where no probe has gone before, marking one of the most significant technological achievements in the annals of the history of science," said a statement by John Grunsfeld, NASA's associate administrator for the Science Mission Directorate.

Voyager 1, with Voyager 2 a few years behind in its travels to the edge of the solar system, sent back data to scientists on Earth on August 25 last year, showing an abrupt drop in energetic charged particles, or cosmic rays, that are produced inside the heliosphere.
It costs $5.4 million per year operate the twin spacecraft

Scientists expected the direction of the magnetic field in space would reverse at the barrier known as the heliopause.

The Voyager 1 magnetometer did not show this change, leading scientists to be extra cautious about declaring whether the spacecraft had left the solar system.

However, an analysis of data from Voyager's plasma wave science instrument between April 9 and May 22 this year showed the spacecraft was in a region with an electron density of about 0.08 per cubic cm.
Voyager 1 facts

Launched from Cape Canaveral on September 5, 1977 onboard a Titan-Centaur rocket
Voyager has been the most distant human-made object in space since 1998, when it passed the Pioneer 10 probe
Between them, Voyager 1 and 2 explored the giant planets of our outer solar system and the moons, rings, and magnetic fields that surround them
Both Voyager spacecraft carry a 12-inch gold-plated copper phonograph record containing sounds and images selected to portray the diversity of life and culture on earth
The records are intended for any intelligent extraterrestrial life form, or future humans, who may find them
Famous space scientist Carl Sagan headed the NASA committee responsible for selecting material for the records

Sources: NASA, Wikipedia

Astrophysicists have projected that the density of electrons in interstellar space would be between 0.05 and 0.22 per cubic cm, placing Voyager in that range.

"Now that we have new, key data, we believe this is humankind's historic leap into interstellar space," said Ed Stone, Voyager project scientist based at the California Institute of Technology, Pasadena.

"The Voyager team needed time to analyse those observations and make sense of them. But we can now answer the question we've all been asking: 'Are we there yet?' Yes, we are."

But not everyone is convinced.

"I don't think it's a certainty Voyager is outside now," space physicist David McComas of the Southwest Research Institute in San Antonio, Texas told Science magazine.

"It may well have crossed," he said. "But without a magnetic field direction change, I don't know what to make of it."

The spacecraft is expected to keep cruising for now, though the radioisotope thermo-electric generators that power it are beginning to run down, and its instruments will have to shut down permanently in 2025, Science reported.

NASA spends $5.4 million per year operating the twin spacecraft.
 

rynner2

Great Old One
Joined
Aug 7, 2001
Messages
55,271
Likes
8,908
Points
284
Location
Under the moon
#52
The spacecraft is expected to keep cruising for now, though the radioisotope thermo-electric generators that power it are beginning to run down, and its instruments will have to shut down permanently in 2025, Science reported.
Chances are that it will outlive me, then...

But I'm grateful that I've been able to follow this adventure, from 1977, when I was in my prime, to now, in my decrepitude...

Go Voyager, go!

And if our civilization should collapse and fall, or even if mankind becomes extinct, the Voyagers will be little reminders that once we did aspire to the stars...
 

rynner2

Great Old One
Joined
Aug 7, 2001
Messages
55,271
Likes
8,908
Points
284
Location
Under the moon
#53
http://www.bbc.co.uk/news/science-environment-24026153

Today, the veteran Nasa mission is almost 19 billion km (12 billion miles) from home.
This distance is so vast that it takes 17 hours now for a radio signal sent from Voyager to reach receivers here on Earth.

...

When the Voyager team put the new data together with information from the other instruments onboard, they calculated the moment of escape to have occurred on or about 25 August, 2012. This conclusion is contained in a report published by the journal Science.

"This is big; it's really impressive - the first human-made object to make it out into interstellar space," said Prof Don Gurnett from the University of Iowa and the principal investigator on the PWS.

On 25 August, 2012, Voyager-1 was some 121 Astronomical Units away. That is, 121 times the separation between the Earth and the Sun.

Breaching the boundary, known technically as the heliopause, was, said the English Astronomer Royal, Prof Sir Martin Rees, a remarkable achievement: "It's utterly astonishing that this fragile artefact, based on 1970s technology, can signal its presence from this immense distance."
 

Bigphoot2

Not sprouts! I hate sprouts.
Joined
Jul 30, 2005
Messages
5,939
Likes
14,094
Points
294
#54
Still going strong!
Voyager 1 Fires Up Thrusters After 37 Years

The Voyager team is able to use a set of four backup thrusters, dormant since 1980. They are located on the back side of the spacecraft in this orientation. Credit: NASA/JPL-Caltech
› Full image and caption
If you tried to start a car that's been sitting in a garage for decades, you might not expect the engine to respond. But a set of thrusters aboard the Voyager 1 spacecraft successfully fired up Wednesday after 37 years without use.

Voyager 1, NASA's farthest and fastest spacecraft, is the only human-made object in interstellar space, the environment between the stars. The spacecraft, which has been flying for 40 years, relies on small devices called thrusters to orient itself so it can communicate with Earth. These thrusters fire in tiny pulses, or "puffs," lasting mere milliseconds, to subtly rotate the spacecraft so that its antenna points at our planet. Now, the Voyager team is able to use a set of four backup thrusters, dormant since 1980.

"With these thrusters that are still functional after 37 years without use, we will be able to extend the life of the Voyager 1 spacecraft by two to three years," said Suzanne Dodd, project manager for Voyager at NASA's Jet Propulsion Laboratory, Pasadena, California.

Since 2014, engineers have noticed that the thrusters Voyager 1 has been using to orient the spacecraft, called "attitude control thrusters," have been degrading. Over time, the thrusters require more puffs to give off the same amount of energy. At 13 billion miles from Earth, there's no mechanic shop nearby to get a tune-up.

The Voyager team assembled a group of propulsion experts at NASA's Jet Propulsion Laboratory, Pasadena, California, to study the problem. Chris Jones, Robert Shotwell, Carl Guernsey and Todd Barber analyzed options and predicted how the spacecraft would respond in different scenarios. They agreed on an unusual solution: Try giving the job of orientation to a set of thrusters that had been asleep for 37 years.

"The Voyager flight team dug up decades-old data and examined the software that was coded in an outdated assembler language, to make sure we could safely test the thrusters," said Jones, chief engineer at JPL.

Etc
https://www.jpl.nasa.gov/news/news.php?feature=7014
 

skinny

Antediluvian
Joined
May 30, 2010
Messages
6,885
Likes
6,254
Points
284
#55
^ Very cool (npi).

And if our civilization should collapse and fall, or even if mankind becomes extinct, the Voyagers will be little reminders that once we did aspire to the stars...
Amen to that.

Evidence of (our) intelligent designs. Be proud, humanity. Capability realised. That's us out there beyond the heliopause, ranging. Checking out the vibe beyond the burbs. Visioning on.
 

GNC

King-Sized Canary
Joined
Aug 25, 2001
Messages
26,875
Likes
11,376
Points
284
#56
If you haven't seen The Farthest, this year's cinema documentary about the Voyagers, I thoroughly recommend it, it's very moving. It was part of the BBC Storyville strand last Thursday, so will be on iPlayer if you're in the UK.
 

Bigphoot2

Not sprouts! I hate sprouts.
Joined
Jul 30, 2005
Messages
5,939
Likes
14,094
Points
294
#59
Voyager 2 has left the Solar System

Nasa's Voyager 2 probe 'leaves the Solar System'
By Victoria GillScience correspondent, BBC News, Washington DC
Image copyrightNASAImage captionVoyager 1 and Voyager 2 launched from Nasa's Kennedy Space Center to explore the outer planets
The Voyager 2 probe, which left Earth in 1977, has become the second human-made object to leave our Solar System.
It was launched 16 days before its twin craft, Voyager 1, but that probe's faster trajectory meant that it was in "the space between the stars" six years before Voyager 2.

etc
https://www.bbc.co.uk/news/science-environment-46502820
 

Schrodinger's Zebra

Waiting and watching and seeking a sign..
Joined
Mar 8, 2018
Messages
2,048
Likes
3,685
Points
154
Location
.. in the wilderness
#60

Whenever I think of this, I also feel a little sad for it... out there all on its own, leaving the Solar System and heading into the unknown... hard to explain, but hopefully you know what I mean?

Anyway... good excuse to play this song, which contains sample sounds from Voyager...


Mankind's ability to send a beautiful machine 12 billion miles out of 'Our System' continues to be contrasted by our inability to function within our own social systems! That's what the song was about.

Andy
 
Top