Voyager1 – so far out, there's no solar wind anymore

What is really amazing is that the probe still operates after over 3 decades, which is a testament to the design team. It’s a SNAP to keep powered up though. – Anthony

Artist concept of Voyager near interstellar space. Image credit: NASA/JPL Artist concept of Voyager near interstellar space. Image credit: NASA/JPL

From NASA JPL: (h/t to Dr. Leif Svalgaard)

PASADENA, Calif. – The 33-year odyssey of NASA’s Voyager 1 spacecraft has reached a distant point at the edge of our solar system where there is no outward motion of solar wind.

Now hurtling toward interstellar space some 17.4 billion kilometers (10.8 billion miles) from the sun, Voyager 1 has crossed into an area where the velocity of the hot ionized gas, or plasma, emanating directly outward from the sun has slowed to zero. Scientists suspect the solar wind has been turned sideways by the pressure from the interstellar wind in the region between stars.

The event is a major milestone in Voyager 1’s passage through the heliosheath, the turbulent outer shell of the sun’s sphere of influence, and the spacecraft’s upcoming departure from our solar system.

“The solar wind has turned the corner,” said Ed Stone, Voyager project scientist based at the California Institute of Technology in Pasadena, Calif. “Voyager 1 is getting close to interstellar space.”

Our sun gives off a stream of charged particles that form a bubble known as the heliosphere around our solar system. The solar wind travels at supersonic speed until it crosses a shockwave called the termination shock. At this point, the solar wind dramatically slows down and heats up in the heliosheath.

Launched on Sept. 5, 1977, Voyager 1 crossed the termination shock in December 2004 into the heliosheath. Scientists have used data from Voyager 1’s Low-Energy Charged Particle Instrument to deduce the solar wind’s velocity. When the speed of the charged particles hitting the outward face of Voyager 1 matched the spacecraft’s speed, researchers knew that the net outward speed of the solar wind was zero. This occurred in June, when Voyager 1 was about 17 billion kilometers (10.6 billion miles) from the sun.

Because the velocities can fluctuate, scientists watched four more monthly readings before they were convinced the solar wind’s outward speed actually had slowed to zero. Analysis of the data shows the velocity of the solar wind has steadily slowed at a rate of about 20 kilometers per second each year (45,000 mph each year) since August 2007, when the solar wind was speeding outward at about 60 kilometers per second (130,000 mph). The outward speed has remained at zero since June.

The results were presented today at the American Geophysical Union meeting in San Francisco.

“When I realized that we were getting solid zeroes, I was amazed,” said Rob Decker, a Voyager Low-Energy Charged Particle Instrument co-investigator and senior staff scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. “Here was Voyager, a spacecraft that has been a workhorse for 33 years, showing us something completely new again.”

Scientists believe Voyager 1 has not crossed the heliosheath into interstellar space. Crossing into interstellar space would mean a sudden drop in the density of hot particles and an increase in the density of cold particles. Scientists are putting the data into their models of the heliosphere’s structure and should be able to better estimate when Voyager 1 will reach interstellar space. Researchers currently estimate Voyager 1 will cross that frontier in about four years.

“In science, there is nothing like a reality check to shake things up, and Voyager 1 provided that with hard facts,” said Tom Krimigis, principal investigator on the Low-Energy Charged Particle Instrument, who is based at the Applied Physics Laboratory and the Academy of Athens, Greece. “Once again, we face the predicament of redoing our models.”

A sister spacecraft, Voyager 2, was launched in Aug. 20, 1977 and has reached a position 14.2 billion kilometers (8.8 billion miles) from the sun. Both spacecraft have been traveling along different trajectories and at different speeds. Voyager 1 is traveling faster, at a speed of about 17 kilometers per second (38,000 mph), compared to Voyager 2’s velocity of 15 kilometers per second (35,000 mph). In the next few years, scientists expect Voyager 2 to encounter the same kind of phenomenon as Voyager 1.

The Voyagers were built by NASA’s Jet Propulsion Laboratory in Pasadena, Calif., which continues to operate both spacecraft. For more information about the Voyager spacecraft, visit: http://www.nasa.gov/voyager . JPL is a division of the California Institute of Technology in Pasadena.

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Pull My Finger

Astounding. Well on its way to meeting Captain Kirk.

John Phillips

“In science, there is nothing like a reality check to shake things up, and Voyager 1 provided that with hard facts,” said Tom Krimigis, principal investigator on the Low-Energy Charged Particle Instrument, who is based at the Applied Physics Laboratory and the Academy of Athens, Greece. “Once again, we face the predicament of redoing our models.”
Except in climate science, which is settled. (<———– sarcasm)

Katherine

“In science, there is nothing like a reality check to shake things up, and Voyager 1 provided that with hard facts,” said Tom Krimigis, principal investigator on the Low-Energy Charged Particle Instrument, who is based at the Applied Physics Laboratory and the Academy of Athens, Greece. “Once again, we face the predicament of redoing our models.”

That’s how science should be done! Now if only climate “scientists” would do the same.

rbateman

What happens to Voyager I when it passes into interstellar space… i.e. – will it then sail along caught in the interstellar wind?
We’ve only a few years to await the answer. Cool.
NASA Space is worth every last penny.

kwik

“Once again, we face the predicament of redoing our models.”
OMG !!

I am a little disappointed they cancelled the other 4 Voyagers. 😉

Djozar

Amazing! Any idea of how long we’ll be able to keep up communications, and the time lag involved?

Andrew30

Amazing.
I have followed this crafts journey for all of its life, I watched the launch and have seen other craft launch and after many years go quiet, but Voyager has been different.
I never thought it would still be able to communicate so much for so long. I once heard a speaker that said the power of the sattelite times the area of the reciver was a constant value, and I have seen over the years that as Voyager got quieter our ears grew bigger and bigger and are now the largest global array of co-ordiated listening devices. Seeking out the flickering signal of a 50 watt light 10 billion miles away. Unbelieveable.
They have and continue to do the impossible. We, and all of science, owe them all a debt of gratitude for both their insight and their craftsmenship. Thank you all.

Rhoda R

NASA used to do good science – cutting edge science. What happened?

The outward speed has remained at zero since June.
This is a big clue to something else. ‘The outward speed has remained at zero’ i.e. is not positive or negative but zero. Since no particle can have zero velocity in all direction, obviously it must be perpendicular, so no an outward component. These solar wind particles would be pulled back by Sun’s gravitation, not along the heliospheric sheet, but at the higher latitudes, forming a return current of protons, closing the loop, creating possibility of a feedback!

Stephen Brown

1977, a good year for design, engineering, planning and execution to have come together to launch such an astounding human achievement.
Voyager 1 must be one of the most incredible accomplishments of our species.
33 years later and BILLIONS of miles away and it is still working.
Stunning.

H.R.

They don’t make ’em like they used to, eh?
Here’s to many more years and more discoveries out of the Voyagers.

yamaka

Andrew30 says:
December 14, 2010 at 2:01 pm
Amazing.
I have followed this crafts journey for all of its life, I watched the launch and have seen other craft launch and after many years go quiet, but Voyager has been different.

They have and continue to do the impossible. We, and all of science, owe them all a debt of gratitude for both their insight and their craftsmenship. Thank you all.
======================================================
Like you I have followed Voyager I & II since their inception.
Sadly, working in Avionics for the last 20 odd years means that I understand that the levels of achievement considered normal for the Voyager era are a forgotten thing. Now “management” dictate the level of achievement considered affordable whilst trying to pretend that the level of engineering & testing is as good as it always was…
If you’ve never come across it, I’d suggest “Skunk Works” as a good (but saddening) read for those working in the industry these days…

Gary D.

It has been 33 years in earth time, but how long has it been travelling in Voyager 1 time?

I’m confused, a not unusual circumstance where this blog is concerned. From the article,

When the speed of the charged particles hitting the outward face of Voyager 1 matched the spacecraft’s speed, researchers knew that the net outward speed of the solar wind was zero.

That says to me the wind velocity is zero relative to the Voyager’s speed, but not zero, say relative to the sun. If relative velocity is zero, then actual (relative to the solar system?) is whatever speed Voyager is moving. Have I missed some key to the story?
cheers,
gary

Jenn Oates

Unbelievably COOL!

Anything is possible

“Now hurtling toward interstellar space some 17.4 billion kilometers (10.8 billion miles) from the sun,”
If I’ve done the maths right, this is 1/2357th of the way to Alpha Centauri, our nearest star, making it another 70,,000 years before Voyager would arrive there were it heading in the right direction.
I hope this gives some sense of the sheer vastness of outer space…..

Tom in freakin cold Florida

V1 has actually traveled farther than the distance shown. Total mile traveled since launch is 13,896,000,000
Check the info at the bottom of this page:
http://voyager.jpl.nasa.gov/mission/weekly-reports/index.htm
That means it has traveled about .86 of a light day in 33 years. At that rate it would take about 60,000 years to reach the next nearest star. Pretty big place out there.

John F. Hultquist

What’s all the fuss about. Here is another vehicle launched about the same time and – you can own it:
http://dixie-dream-cars.ebizautos.com/detail-1977-cadillac-eldorado-cabriolet-used-1176793.html
Has fewer miles too!

Rational Debate

It makes me proud. Gives me one of those warm fuzzy feelings, proud of what we (mankind) has managed at times to accomplish. Can you imagine the pride of the folks who were directly involved in the design and manufacture, and in dealing with any technical problems that may have been encountered along the way?
Talk about awe inspiring in so many different ways. May Voyager continue to have a very very long life, sending us all sorts of nifty tidbits!

Fit_Nick

I am sure i saw Blue Peter do an arcticle on this in their studio on what Voyager was going to do and what it was also taking with it about our planet, the ‘Golden Record’.. Goodness me that makes me feel old… !!
When are NASA going to make time capsules??

Doug in Seattle

Rhoda R says:
December 14, 2010 at 2:02 pm
NASA used to do good science – cutting edge science. What happened?

They realized that our trust, which they had earned, could be used to fund ever more ambitious things, and ultimately be used to direct policy at the highest level of government.
In other words they have abused our trust and no longer deserve it.

gary turner says:
December 14, 2010 at 2:40 pm

I’m confused, a not unusual circumstance where this blog is concerned. From the article,

When the speed of the charged particles hitting the outward face of Voyager 1 matched the spacecraft’s speed, researchers knew that the net outward speed of the solar wind was zero.

That says to me the wind velocity is zero relative to the Voyager’s speed, but not zero, say relative to the sun. If relative velocity is zero, then actual (relative to the solar system?) is whatever speed Voyager is moving. Have I missed some key to the story?

When the particles hitting the ship are hitting at exactly the same speed as the ship is moving, then the particles are (at least in the direction of travel) not moving.
The key is they are not at zero velocity relative to the ship, but at zero velocity relative to the Sun.

ShrNfr

And every year they have to fight for the couple of million dollars to keep funding the analysis of data. My wife works on the Voyager 2 data and it is year to year as to if she will have a job.

DesertYote

My dad was involved with these missions, back when NASA meant science. Three of the missions I work never made it. One blew up (with the Challenger 🙁 ), one just disappeared, and one made a big crater. At least some of the stuff I worked on has made it 20 years. Boy I hate socialists. They destroy everything they touch in the name of ideology.
Now, NASAs latest chief scientist is a AWG propagandist, Waleed “The Ice is Melting” Abdalati.
http://www.nasa.gov/topics/people/features/abdalati.html
Providing a foundation for propaganda is so much more important then providing a foundation for science. We can kiss space good bye.

There’s even a song:

If you like that you might like the rest of “Minus Ten and Counting” also.
Just search for it on YouTube.

Mark T

NASA space scientist: “The data does not match our models. Our models must be wrong.”
NASA climate scientist: “The data does not match our models. The data must be wrong.”
These people work for the same “company?”
Mark

DesertYote

yamaka
December 14, 2010 at 2:24 pm
###
I also witnessed the destruction of a culture of excellence from the inside. I do believe the destruction was deliberate, having lived through the democratic parties GAO witch hunts of the late 80s. They literally set this country back a decade on technology and tripled the cost of doing anything.
This “Work with Business to get to Space” thing they are now advertising, is just a scam. SpaceX is a crony capitalist venture that is in bed with the current administration. I mean, everything NASA has ever built was built by businesses.
Sorry if I sound bitter, but I am.

DirkH

“Once again, we face the predicament of redoing our models.”
I have yet to hear such an honest statement from a climate modeler.

DirkH

Doug in Seattle says:
December 14, 2010 at 3:00 pm
“They realized that our trust, which they had earned, could be used to fund ever more ambitious things,[…]”
Like not measuring the temperature in Bolivia. Doesn’t sound THAT ambitious to me…

Jimash

V-ger is indeed a great accomplishment . I remember all the planet-stops. Inspiring.
All the “vastness” talk is defeatism.
It took a mere 100 years to go from coal fed railroads to Voyager.
If we kept at it “vastness” would just be a matter of patience, eventually.
Of course, our current administration really doesn’t believe in manned spaceflight.
So very soon Astronauts will be hitting the unemployment line, while Asimo takes their jobs.
“They took our jobs “!

hotrod (Larry L)

Djozar says:
December 14, 2010 at 1:58 pm
Amazing! Any idea of how long we’ll be able to keep up communications, and the time lag involved?

If my math is right, the radio delay would be about 16.1222646012 hours, based on their 14.4 Billion Km distance or about .67 light days.
So somewhere between .67 and .86 light days.
Now if we develop warp drive in another 33 years we will be able to run it down in less than 2 days travel at light speed 😉
Larry

Eric Dailey

There is a reason why NASA doesn’t do Voyager level exploration now but you are not meant to know about it . If you will stop believing everything you read in the press and hear on TV you can begin to find out what is really going on.
Americas’ finest engineers and scientists did not become stupid all of a sudden in 1985. Somebody is driving this wreck and they mean to run it in the ground.

Dr. Dave

To get some perspective on just how amazing this is consider the state of consumer electronics in 1977 compared to today. There aren’t even a lot of cars from 1977 that still function unless they have been completely refurbished. What was cutting edge in 1977? A really good cartridge on your turntable? A cassette deck? Maybe a digital watch or a calculator? Little CB radios with 4 watts of output on the 11 meter band were about the best mobile communications that average citizen could hope for. Even much more sophisticated 2m VHF rigs for hams were crude by today’s standards. The average home didn’t have a computer. Virtually no one had a cell phone.
Now consider that against this backdrop NASA engineers designed and built a space craft that is STILL sending useful information back to Earth 33 years later. I have an electric shoe polisher from 1968 that still functions amazingly well. Other than that I don’t possess a single item that takes batteries or plugs into the wall that is 33 years old.

Regg_upnorth

He wrotes:
What is really amazing is that the probe still operates after over 3 decades, which is a testament to the design team
Well of course it is still operating, it’s not running on fossils fuel. Electric power with radioactive generator.

Robert of Ottawa

vukcevic,
generally, space plasmas are neutral in charge, so there is no electrical current. However, the sheath may separate the charges, with electrons heading North and ions heading South – or whichever. Interesting thought though.

Steve Oregon

Dave Bowman: Hello, HAL. Do you read me, HAL?
HAL: Affirmative, Dave. I read you.
Dave Bowman: Open the pod bay doors, HAL.
HAL: I’m sorry, Dave. I’m afraid I can’t do that.
Dave Bowman: What’s the problem?
HAL: I think you know what the problem is just as well as I do.
Dave Bowman: What are you talking about, HAL?
HAL: This mission is too important for me to allow you to jeopardize it.
Dave Bowman: I don’t know what you’re talking about, HAL.
HAL: I know that you and Frank were planning to disconnect me, and I’m afraid that’s something I cannot allow to happen.
Dave Bowman: Where the hell’d you get that idea, HAL?
HAL: Dave, although you took very thorough precautions in the pod against my hearing you, I could see your lips move.
Dave Bowman: Alright, HAL. I’ll go in through the emergency airlock.
HAL: Without your space helmet, Dave, you’re going to find that rather difficult.
Dave Bowman: HAL, I won’t argue with you anymore. Open the doors.
HAL: Dave, this conversation can serve no purpose anymore. Goodbye.

Gary D. says:
December 14, 2010 at 2:39 pm
It has been 33 years in earth time, but how long has it been travelling in Voyager 1 time?
=============================================================
Arf, Arf, 231??

Carla

33 years and keeps on ticking. Pretty impressive.
swt
Still.. the dent and ribbon, haven’t given up all their secrets yet.
10Au difference in the Voyagers distance is still intriguing for me.
That would be quite alot of turbulence or two different interstellar flow directions striking the heliospheric nose, type location or.. I’m tired zzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzzz

Monty

This kind of thing inspired me to become an engineer. Unfortunately I arrived fresh out of school at a prime contractor working under NASA to discover that what I wanted to do was over with before I was born….sad. Oh well, life moves on, still inspired by what was done way back when before all the *change*. I jumped ship and haven’t looked back. A wise move in retrospect.
Those of you on the outside looking in have no idea how dysfunctional the place is. JPL does some neat things, but the rot flows from the top down. I no longer support NASA. I think the space science should be farmed out to various universities, with grants to continue the actual science missions. Climate data….I’ll listen to the people the commodities traders pay…..
As far as the analogies to the progress made in the previous first half of the last century, the theoretical framework was there for the physics at least a century ago. We are up against a brick wall there right now. Poo-Poo the vastness of space at your peril. It’s a big cold universe out there and it makes Antarctica look like palm beach.
I sure hope there is somebody working on the flux capacitor warp drive in their garage. Something that will cause the Physicists to re-write their models, but short of that…the rocket equation is a b&*%ch. Nothing in my life has ever been as disappointing as that realization. Other than the fact that if there is that person out there and they succeed….they will be sent to the gulag for crimes against the planet if discovered. Oh, and I’m stuck here with the dead-enders.

Just returning from AGU, hence this late repsonse.
vukcevic says:
December 14, 2010 at 2:03 pm
These solar wind particles would be pulled back by Sun’s gravitation, not along the heliospheric sheet, but at the higher latitudes, forming a return current of protons, closing the loop, creating possibility of a feedback!
Robert of Ottawa says:
December 14, 2010 at 5:07 pm
generally, space plasmas are neutral in charge, so there is no electrical current. However, the sheath may separate the charges, with electrons heading North and ions heading South – or whichever.
As Robert says there is no electric return current. Sadly, the press release is completely screwed up. Voyager 1 is now just matching the solar wind speed, which means that they both travel outwards at 17 km/sec [for the moment]. The solar particles left the Sun with a speed higher than the escape velocity and will therefore never return to the Sun [and surely not ‘at higher latitudes’ – what makes them go up there?]. When the solar wind hits the Earth’s magnetic field it is also deflected around the Earth. And the wind is still moving outwards at 17 km/sec, so has not slowed to zero. NASA gets an F for this nonsense.

Jimash

” Poo-Poo the vastness of space at your peril.”
While completely respecting your opinion, and even more, your facts, I would say I don’t poo-poo it, I sort of embrace it.
Shouldn’t there be something between chemical rockets and flux-capacitor warp drives ?

Baa Humbug

Fascinating.
Obviously the New York office of GISS had nothing to do with the data interpretation.
Also, having been built in the 70’s, the Voyagers had no parts built in China, hence they last.
Further, politicians aren’t demanding a particular outcome from the Voyager venture.
All the above leads me to believe this story rather than not.
p.s. Can an amateur intercept the Voyager signals or just NASA? Just asking.

Roger Carr

John F. Hultquist says: (December 14, 2010 at 2:50 pm) What’s all the fuss about. Here is another vehicle launched about the same time and – you can own it:
But the steering wheel’s on the wrong side, John…

Leif Svalgaard says:
“Voyager 1 is now just matching the solar wind speed, which means that they both travel outwards at 17 km/sec”
This was under the interpretation that the speed was relative to the space craft. Actually, the solar wind speed monitor failed back in 1980, and Voyager 1 cannot measure the solar wind speed directly. It is, however, possible to estimate the speed from the distribution of low-energy particles hitting the spacecraft. The abstract [I didn’t hear the talk – too much going on] reads:
AN: SH23D-02
TI: Low-energy Charged Particles at Voyagers 1 and 2 10-20 AU into the Heliosheath (Invited)
AU: *Decker, R B
EM: robert.decker@jhuapl.edu
AF: Space, Johns Hopkins Univ. Applied Physcis Lab., Laurel, MD, USA
AB: Voyager 1 (115 AU, N34°) and Voyager 2 (93 AU, S29°) have been in the heliosheath since Dec. 2004 and Sep. 2007, respectively. Intensities of low-energy ions 40 keV – few MeV observed at Voyager 1 have been relatively steady since mid-2006. The heliosheath-averaged (5.6-year) Voyager 1 energy spectrum rolls over slightly with increasing energy, with the spectral index changing from -1.5 to -1.7. Intensities of ions 30 keV – few MeV observed at Voyager 2 have been relatively steady since about 2009.4, in contrast to the large quasi-recurrent variations observed from 2007.66 (termination shock) to 2009.4. The low-energy ion energy spectrum at Voyager 2 is slightly harder than that at Voyager 1. The Voyager 2 spectrum averaged over 2007.66-2009.4 shows a rollover, with the spectral index changing from -1.3 to -1.5. After about 2009.4 at Voyager 2, the lower energy ion channels show large anisotropies consistent with the observed direction of heliosheath plasma flow, but not with its speed. Preliminary analysis suggests that in addition to H+, these channels may also be measuring heavy ions, i.e., pickup He+ and/or O+ at energies gt 4 and gt keV/nuc, respectively, that could be boosted into sunward viewing sectors of the detector by the ~150 km/s heliosheath flow. Intensities of energetic (0.02-1.5 MeV) heliosheath electrons began decreasing exponentially at Voyager 2 on 2009.15, and are now at detection background. Energetic electron intensities at Voyager 1 remain high. We estimate the heliosheath plasma flow velocity in the R-T (instrument scan) plane at Voyager 1 by using angular data from the three lowest energy ion channels that cover 40-139 keV. We cannot measure the component of flow normal to the R-T plane. During 2007.7-2010.5, the estimated radial component of flow decreased from ~60 km/s to ~0 km/s at a rate of -20 km/s/yr. On average, the tangential component of flow has been at about -40 km/s from termination shock crossing onward, but continues to show broad variations of ±20 km/s.
This would mean that the spacecraft is now ploughing into the wind at 17 km/s. So, the interpretation of a sideways deflection seems to be reasonable. If so, the solar wind has been slowed by interaction with the interstellar medium, and is no longer just coasting outward. The particles cannot return to the Sun as they will be picked up by the outflow if they moved closer. The solar wind keeps both its own debris and interstellar ions at bay.

Mark Wagner

Amazing! Any idea of how long we’ll be able to keep up communications, and the time lag involved?
Both Voyagers have enough electrical power and thruster fuel to last until around 2020. Current communication time is about 13 hours one way.
It’s my understanding that they have to disable instruments along the way to compensate for declining electrical output and only a few instruments are still operational. The radio will be the last to power off.

Monty ,
The good people who can do this sort of stuff aren’t at NASA anymore. Their modern equivalents are working at SpaceX working on Falcons and Dragons, as shown by their OUTSTANDING performance last week.

savethesharks

Mind-blowing!
Chris
Norfolk, VA, USA

Jason Calley

Gary D. says:
December 14, 2010 at 2:39 pm
It has been 33 years in earth time, but how long has it been travelling in Voyager 1 time?
Someone check my math, I am a bit rusty, but if Voyager had been travelling at its current speed of 17 km/sec for all 33 years, it would have experienced a time dilation of about .016 seconds. In reality it was travelling faster earlier in its life, but still, I would not expect it to have accumulated more than perhaps .03 seconds total.
Got to go REAL fast before relativity makes much difference.

KR

Fantastic! Thanks for posting this.