43 years and 14 billion miles later, Voyager 1 still crunching data to reveal secrets of the interstellar medium
- Reference: 1620727385
- News link: https://www.theregister.co.uk/2021/05/11/voyager_1_interstellar_medium/
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Scientists at Cornell University have used data from the spacecraft, first launched in 1977, to uncover a weak signal that details interstellar plasma density over about 10 au (astronomical unit, roughly the distance from Earth to the Sun) with an average sampling distance of 0.03 au, according to a [1]paper in Nature Astronomy .
Voyager 1, whose original mission was supposed to finish in 1980, crossed the heliopause in 2012, making it the first human-made object to do so. This gave researchers an opportunity to directly measure activity outside the solar system, or at least as much as the spacecraft's ageing arsenal of instruments would allow.
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Interstellar plasma is a dilute gas of neutral and ionized particles. Using a repurposed [5]Plasma Wave Subsystem , designed to record data on the magnetospheres of planets like Jupiter and Saturn, Voyager 1 was able to measure the medium, but only in the presence of solar events, lead author Stella Ocker told The Register .
[6]Voyager 1 fires thrusters last used in 1980 – and they worked!
[7]Considering the colonisation of Mars? Werner Herzog would like a word
[8]Let's go space truckin': 1970s probe Voyager 1 is now 14 billion miles from home
[9]Imagine surviving WW3, rebuilding computers, opening up GitHub's underground vault just to relive JavaScript
"Previously, to measure the density you had to wait for a so-called plasma oscillation event, a finite burst of plasma activity that's triggered by solar activity like coronal mass ejections which send shock waves out into the interstellar medium," she said. "Now, we can measure the plasma density in the absence of these plasma oscillation events, allowing us to trace underlying properties of the plasma and see how the plasma is responding to these shock waves from the Sun. This work gives us the most complete map of the plasma along Voyager 1's trajectory to date."
The original plan for the Voyager project was only to fly by gas giants Jupiter and Saturn following some NASA descoping. Voyager 1 and sister probe Voyager 2 passed Jupiter in 1979 with Voyager 1 performing a flyby of Saturn and its moon, Titan, in 1980. Voyager 2 made its Saturn flyby in 1981.
Having seen sense, NASA extended the mission, and Voyager 2 took in Uranus in 1986 and Neptune in 1989. Voyager 1 headed off out of the Solar System on a course that could allow the probe to turn its imaging platform back toward Earth and capture a "family portrait" of the Solar System, and the [10]Blue Dot image made famous by Carl Sagan in 1990 .
Yet a new generation of researchers is finding value in Voyager's data.
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Born nearly two decades after the spacecrafts launched, Ocker has a keen interest in studying the interstellar medium as a graduate researcher at Cornell's Department of Astronomy.
"I never even thought using Voyager data would be a possibility until my second year of graduate school (in 2019), when my advisor pointed out an opportunity to work on the Voyager team through the NASA Outer Heliosphere Guest Investigator Program," she said. "When we saw the opportunity to work with Voyager, we jumped at it. It's been absolutely thrilling to work with a spacecraft that has such an incredible legacy."
But, now 14 billion miles from Earth, the probe will not continue to send data indefinitely. It is not expected to have the power remaining to operate a [12]single scientific instrument beyond 2025 .
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Still, Ocker and the team hope to make the most use of the data while they can.
"I'm very hopeful that we can continue to measure this new signal with Voyager 1, but I don't know how much longer the spacecraft will be able to collect the high-resolution data that we need to detect this signal."
The information could provide insight into where extremely narrowband, weak plasma waves come from and how far away Voyager 1 needs to go to see the "quiescent" interstellar medium, beyond significant activity related to the Sun, Ocker said. ®
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[1] https://dx.doi.org/10.1038/s41550-021-01363-7
[2] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2YJqqHUaFsC-BZIfg1ddccQAAAFY&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[3] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44YJqqHUaFsC-BZIfg1ddccQAAAFY&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
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[5] https://en.wikipedia.org/wiki/Plasma_Wave_Subsystem
[6] http://www.theregister.com/2017/12/04/voyager_1_mission_extension_thanks_assmbler_code_and_thrusters_unused_since_1980/
[7] http://www.theregister.com/2020/11/25/herzog_slams_musk_mars_plan/
[8] http://www.theregister.com/2020/09/18/voyager_1_14_billion_miles/
[9] http://www.theregister.com/2020/07/17/github_svalbard_storage/
[10] https://www.theregister.com/2020/02/14/pale_blue_dot/
[11] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44YJqqHUaFsC-BZIfg1ddccQAAAFY&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[12] https://en.wikipedia.org/wiki/Voyager_1#Remaining_lifespan
[13] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_offbeat/science&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33YJqqHUaFsC-BZIfg1ddccQAAAFY&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[14] https://whitepapers.theregister.com/
"It is not expected to have the power remaining to operate a single scientific instrument beyond 2025."
I wouldn't put it past the abilities of this amazing team to devise some means of enabling an instrument to be used intermittently even beyond that date. And I'm sure there'll be investigators working through the existing data a good while after that.
It's good to be reminded of the best we humans are capable of.
"It's been absolutely thrilling to work with a spacecraft that has such an incredible legacy"
I'll bet it is.
It is incredible that we've been able to do such things. It is indispensible that we continue to milk Voyager for every ounce of scientific data we can get while we still can.
And it is a tribute to Science and to the entire human race that NASA selflessly grants access to such data, instead of hoarding it.
I'm not saying that NASA has a habit of hoarding data, I'm saying that NASA is the embodiement of Knowledge, giving access without hesitation to any data it has on our Universe.
There are some forces for Good in our world, and NASA is one of them.
A sign of (past) times
This is a testament to the days when in order to try to ensure that something would last it's expected life, it was over-engineered.
We now know so much about materials science that we can engineer to the limits of the materials. These new things will not last in the same way.
I'm not sure whether this is a good thing or not. On one hand, we get much more bang for the buck during the initial mission. On the other, we're less likely to get these amazing windfalls in the future.
43 years
Was that before or after the pandemic started?
Re: 43 years
meh, as I see it, today is the 437th of March, 2020
Re: 43 years
>Was that before or after the pandemic started?
Yes
I like to think
That one day humanity will catch up with Voyager, give it an overhaul and up grade it then set it back on its path outward from Sol to continue doing the incredible job it has done so far.
Re: I like to think
Wasn't there an science fiction story in which a later Earth spaceship smashed into it? Possibly by Arthur C. Clarke?
Re: I like to think
One of the Star Trek films ("The Search for Spock" I think) started with a Klingon Bird of Prey destroying an old probe that looks remarkably like Voyager. Also in the original Star Trek film, V'ger was a Voyager-class probe that had been massively upgraded by an alien civilisation (you caught a glimpse of the probe hidden in the core of the vat V'ger structure).
The link budget for this distance would be interesting.
Often overlooked
Our ability to get the really weak radio signals back from the probe.
We continue to pollute the radio spectrum on our planet like all the other things we screw up!
Also one has to wonder where our early radio transmissions have got to by now.
Re: Often overlooked
Over a hundred light years.
Now, that's a sobering thought (and a bit early in the day to start correcting it).
Re: Often overlooked
... a bit early in the day to start correcting it...
I think you mean that its a bit too late. The vast invasion fleet is already on its way (that is until it gets swallowed by small dog - scale is a bugger sometimes).
Re: Often overlooked
I believe the 'too early' was referring to it being too early to correct the sobriety issue!
But then the sun is always over the yardarm somewhere!
Re: Often overlooked
Indeed. But not here at the time.
Re: Often overlooked
Well they were beaming Coldplay into space last week, any civilisations that weren't already on their way to wipe us out will definitely have set off now
Re: Often overlooked
Just in my lifetime (and speaking from my own country, YMMV):
* Growth of analog TV channels, then sudden conversion to digital = likely lower total broadcast power and less "noise" of spillage to other frequencies.
* Death of many radio stations (which may have a digital conversion of their own someday).
* Rise of analog mobile phones, then quickly killed for digital, which is limited to only a few frequency bands.
* Rise of Wi-Fi, again limited in frequency spread.
* Overall better EM design in many products compared to industry and appliances of 50 to 100 years ago.
Does this actually mean we're wasting less EM/RF into space even as we use more in this thin shell of atmosphere? Maybe. Can NASA tell us?
Re: Often overlooked
Doesn't really matter, every frequency is used in multiple locations around the globe, that's not a problem on the ground as you will only get the one that's nearest to you but out in space they are all about the same distance away so extracting a single signal from the mush of multiple signals would be pretty close to impossible.
In fact the combined mush might be indistinguishable from random noise.
Uplink spill might be detectable from a distance but that will sweeping round like a lighthouse beam as the Earth rotates so that's not too much of a concern.
Progress...
So we can get a signal from a satellite that is 43 years old, and 14 billion miles away, yet I struggled to get Radio 2 on my car stereo when I ventured into the sticks last week.
That's progress for you.
Re: Progress...
I would suggest fitting a 70M steerable dish to your car roof, then all you need is an auto steer mechanism to keep it aligned with the nearest transmitter.
Re: Progress...
Out here in the sticks is where they stick the VHF transmitter at 250kw ERP per channel. On top of what my granddaughter, when a toddler, thought was a stick on the horizon until we took her closer to see it disappearing several hundred feet into the sky.
1977
Form 4 at high school.
We did a project on Voyager.
Still can’t fathom the distances involved.
Re: 1977
> Still can’t fathom the distances involved.
If you 'fathom' it 12320000000000 times you'll be in the ballpark of 14 billion miles.
Voyager
The probes that just keep on giving, decades after any reasonable person would have assumed that they had died.
If one can value sent by a 43-old space probe, imagine the value of the data collected from any online usage.
Anyway, Voyager is the proof that nuclear technology is very efficient to be a long-lasting and reliable source of energy!
> nuclear technology is very efficient
It's not really "nuclear" technology as we usually understand it, it's just a radioisotope thermoelectric generator ( [1]Wikipedia ).
There is no fission or fusion, or whatever else we call "nuclear power" going on, just a normal, natural process you find all around you in nature.
[1] https://en.wikipedia.org/wiki/Radioisotope_thermoelectric_generator
There is no fission or fusion, or whatever else we call "nuclear power" going on
Not strictly true. What they use is the heat from radioactive decay, much the same as in a nuclear power plant just a lot less heat.
Sky is closing
> It is not expected to have the power remaining to operate a single scientific instrument beyond 2025.
Not to mention we might be unable to listen to its incredibly weak signal by then, even if it had enough power left: Money talks louder.
Shades of Spirit
Have I been a good robot? Is it time to come home yet?
"Born nearly two decades after the spacecrafts launched"
Respect to those engineers and scientists who built it, and those who continue to push the boundaries (from someone born nearly 2 decades before they launched!)