Author Topic: NASA - Voyager 1 and 2 updates  (Read 173045 times)

Offline Chris Bergin

Re: NASA - Voyager 1 and 2 updates
« Reply #140 on: 09/14/2013 03:51 am »
A good question from a friend of mine....

If Voyager was made today, using today's technology, how long do you think you could keep it going, given Voyager is expected to power off completely in 10-15 years or so?
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Offline Bubbinski

Re: NASA - Voyager 1 and 2 updates
« Reply #141 on: 09/14/2013 05:41 am »
I have also been wondering about something re: interstellar space and Voyager's results reported so far.  There was a big uptick in cosmic rays when she broke through to the other side.

Question: What would happen if you were to magically put, say, the ISS, right where Voyager 1 is now.  With what we know, would the crew of ISS survive okay in interstellar space, or is the radiation environment not habitable?
I'll even excitedly look forward to "flags and footprints" and suborbital missions. Just fly...somewhere.

Offline baldusi

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Re: NASA - Voyager 1 and 2 updates
« Reply #142 on: 09/14/2013 02:47 pm »
A good question from a friend of mine....

If Voyager was made today, using today's technology, how long do you think you could keep it going, given Voyager is expected to power off completely in 10-15 years or so?
Pu238 decay is equal for everybody. In fact, new production might not even be that pure, since they might mix new batches with old (couple of dacades of decay). And, if I remember correctly, the SiGe thermoucouples are no longer available. But I guess that would only mean more mass. If more mass is acceptable, you could use Americum-241, which has a half life of over 400 years, but requires a bit more shielding and has worse specific energy. But that's just the power issues. Voyager use core memory, which is impervious to radiation. I don't think modern electronics are upto a 80year tolerance to deep space radiation. Nor modern sensors.

Offline a_langwich

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Re: NASA - Voyager 1 and 2 updates
« Reply #143 on: 09/14/2013 09:39 pm »
A good question from a friend of mine....

If Voyager was made today, using today's technology, how long do you think you could keep it going, given Voyager is expected to power off completely in 10-15 years or so?

If you just look at the power question, it's easy:  doubling the size of the RTG, or halving the power budget, would double the useful lifetime.  But getting all the components to last even as long as the Voyagers have is exceedingly tough.

Examining the New Horizons probe is instructive.  There's a history of it and various other predecessor proposals for Pluto / Kuiper Belt probes at http://www.boulder.swri.edu/pkb/ssr/ssr-intro.pdf .  In particular, the Voyagers massed 722 kg and had a 420 W power budget, while New Horizons massed 428 kg and had a 228 W power budget. 

That history describes several wild swings during the history of proposed Pluto probes.  At one point, a NASA group (PFF) was trying to hit a total spacecraft size of 50 kg, with 9 kg for science instruments, but the size ballooned to 140 kg total, still only 9 kg for science.  :(  Pluto Express, or Pluto-Kuiper Express, was a follow-on design for a 175 kg spacecraft, still only 9 kg for the science payload.  The New Horizons proposal added mass to get the science instrument mass budget to around 30 kg.  That allowed many redundant systems to be added, which increases reliability via backups.  It also allowed the use of more conservative designs, which may increase reliability a bit, but is essential for getting the project approved, helping it through the Hall of Whirling Axes budget process, and avoiding cost overruns which would send it back to the Hall of Whirling Axes.

Maybe I should note that the New Horizons power budget was not designed to be as small as possible, but was designed to fit a particular RTG they were offered by NASA, and maximize the amount of science produced (~ power usage) for that power budget, which of course is getting smaller over time.

Voyager's primary mission lasted 3 years, so I imagine that was its primary design lifetime.  Asking if we could now design a probe to last longer than the 36 years we've been exceedingly lucky to get, is tackling a design problem orders of magnitude harder than Voyager's design.  It assumes that if we launched an exact duplicate of Voyager, we'd get the same lifetime, and that's probably unlikely.  A very similar argument could be made about designing a Mars rover to last longer than Opportunity. 

I think New Horizons' targeted lifetime is about 15 years, which is similar to GEO satellites, which to my knowledge is about the longest time frame for which electronic systems are designed to last without any parts replacement.


Offline Robotbeat

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Re: NASA - Voyager 1 and 2 updates
« Reply #144 on: 09/14/2013 09:49 pm »
I would argue that amount of science produced is more proportional to the logarithm of the power available, but that's just me. ;)
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Offline Chris Bergin

Re: NASA - Voyager 1 and 2 updates
« Reply #145 on: 09/15/2013 12:22 am »
Thanks for the responses guys.

And here's Chris Gebhardt's feature article on the historic announcement:

Into the unknown: Voyager 1 begins interstellar space adventure
http://www.nasaspaceflight.com/2013/09/the-unknown-voyager-1-begins-interstellar-space-adventure/
Hosted thread: http://forum.nasaspaceflight.com/index.php?topic=32856.0
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Offline joek

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Re: NASA - Voyager 1 and 2 updates
« Reply #146 on: 09/15/2013 04:13 am »
A good question from a friend of mine....

If Voyager was made today, using today's technology, how long do you think you could keep it going, given Voyager is expected to power off completely in 10-15 years or so?

As others have suggested, essentially as long as there is sufficient power.  Hard to compare the RTG's then with what might be fielded today.  Rad hardening is much better understood now than then.  Today's components would allow at least as much, if not more, rad resistance and resiliency as then.

Also depends on whether you intend to retrace Voyager's path, and specifically Jupiter encounter.  (Arguably we only really started to understand what "rad hard" meant in practice for outer planet missions, and develop the discipline to deal with it, after Pioneer 10 Jupiter encounter when it became apparent just how nasty it can be.)  Beyond that, providing a good thermal environment for the electronics (which for some configurations depends on electric power) appears to be a key element in prolonging life.

I'm not sure how much people appreciate that it was not so much the technology per-se at that time that has allowed Voyager to survive, but the selection and application of the available technology, and the amount of rework that was required after the results from Pioneer 10's Jupiter encounter were received, which arguably resulted in Voyager overbuilt for the perceived hazards.

In short, if Voyager was built today, using today's available technology (power being the wildcard), and with a similarly paranoid attitude towards the unknown, then I have no doubt it would last at least as long, and likely far longer.

Offline baldusi

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Re: NASA - Voyager 1 and 2 updates
« Reply #147 on: 09/15/2013 12:42 pm »
I'm still not convinced current electronics can be more rad hard than those. At least I'm pretty sure that memony isn't. Core memory is a hand weaved matrix of wires and metallic rings. The feature size is measured in 0.1mm. In those sizes cosmic rays are simply not an issue. Thermal and vibration would be critical, though. Regarding processing, yes, current IC might be better.
But, the critical issue would be how would you get to the final acceleration. GA at Jupiter are hard (thermal, magnetic and radiation wise).

Offline ugordan

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Re: NASA - Voyager 1 and 2 updates
« Reply #148 on: 09/15/2013 12:47 pm »
At least I'm pretty sure that memony isn't.

Cassini was one of the first planetary missions to use solid state memory and has been in space for 16 years now. I remember one episode with a bad memory sector during that time, but that seems to have been it. I don't see why radiation would be a showstopper for a 30+ year mission.

Offline Bob Shaw

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Re: NASA - Voyager 1 and 2 updates
« Reply #149 on: 09/15/2013 01:05 pm »
The early circumsolar Pioneers (late 60s) lasted longer than the Voyagers, with mid 1960s electronics and solar cells. I seem to recall that they were being listened to now and again until quite recently. Like outer planet Pioneers they were spin stabilised particles and fields spacecraft. I don't think they even had a tape recorder (generally the weak spot in early US efforts, that and batteries). There are several other ancient spacecraft out there, still ticking away in the sunshine.

Offline Nomadd

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Re: NASA - Voyager 1 and 2 updates
« Reply #150 on: 09/15/2013 01:39 pm »
A good question from a friend of mine....

If Voyager was made today, using today's technology, how long do you think you could keep it going, given Voyager is expected to power off completely in 10-15 years or so?
Most of the responses are missing the problem. It's not the size of the RTG or the half-life of the P238 that's Voyager's limiting factor. It's the degrading thermocouples in the RTGs that are reducing their output. The ones now days, like in New Horizons, are much better in that respect and shouldn't be a problem, so it should maintain power levels much longer. And electronics don't really wear out. The probe could very well be functional 60 years from now. Comms range might be the limit. New Horizons has a smaller and lower gain antenna than Voyager. Taking a wild-ass guess that the receiver is about 3db more sensitive than Voyager's, they should have about the same receive range. I don't know New Horizon's output power on the high gain dish so can't guess the transmit range.  But I assume the DSN will continue to improve over the next half century, so 60 years isn't out of the question.
 Of course, running out of fuel for desaturating reaction wheels could screw up that whole estimate. But I assume it won't need much of that since it probably won't be doing that much pointing after it's hoped for encounter with some Kuiper Belt object after Pluto.
« Last Edit: 09/15/2013 01:44 pm by Nomadd »
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Online jebbo

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Re: NASA - Voyager 1 and 2 updates
« Reply #151 on: 09/15/2013 05:26 pm »
And electronics don't really wear out.

Actually at small process geometries they can thanks to electromigration.  However, I agree with your basic point. This is a well known issue and all design tools check for minimum lifetimes, etc.  Actually, now I'm wondering if the thermocouple degradation is due to this . . . wasn't as well understood back then.

Offline Star One

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NASA - Voyager 1 and 2 updates
« Reply #152 on: 07/08/2014 07:15 pm »
Sun Sends More 'Tsunami Waves' to Voyager 1

NASA's Voyager 1 spacecraft has experienced a new "tsunami wave" from the sun as it sails through interstellar space. Such waves are what led scientists to the conclusion, in the fall of 2013, that Voyager had indeed left our sun's bubble, entering a new frontier.
"Normally, interstellar space is like a quiet lake," said Ed Stone of the California Institute of Technology in Pasadena, California, the mission's project scientist since 1972. "But when our sun has a burst, it sends a shock wave outward that reaches Voyager about a year later. The wave causes the plasma surrounding the spacecraft to sing."
Data from this newest tsunami wave generated by our sun confirm that Voyager is in interstellar space -- a region between the stars filled with a thin soup of charged particles, also known as plasma. The mission has not left the solar system -- it has yet to reach a final halo of comets surrounding our sun -- but it broke through the wind-blown bubble, or heliosphere, encasing our sun. Voyager is the farthest human-made probe from Earth, and the first to enter the vast sea between stars.
"All is not quiet around Voyager," said Don Gurnett of the University of Iowa, Iowa City, the principal investigator of the plasma wave instrument on Voyager, which collected the definitive evidence that Voyager 1 had left the sun's heliosphere. "We're excited to analyze these new data. So far, we can say that it confirms we are in interstellar space."
Our sun goes through periods of increased activity, where it explosively ejects material from its surface, flinging it outward. These events, called coronal mass ejections, generate shock, or pressure, waves. Three such waves have reached Voyager 1 since it entered interstellar space in 2012. The first was too small to be noticed when it occurred and was only discovered later, but the second was clearly registered by the spacecraft's cosmic ray instrument in March of 2013.
Cosmic rays are energetic charged particles that come from nearby stars in the Milky Way galaxy. The sun's shock waves push these particles around like buoys in a tsunami. Data from the cosmic ray instrument tell researchers that a shock wave from the sun has hit.
Meanwhile, another instrument on Voyager registers the shock waves, too. The plasma wave instrument can detect oscillations of the plasma electrons.
"The tsunami wave rings the plasma like a bell," said Stone. "While the plasma wave instrument lets us measure the frequency of this ringing, the cosmic ray instrument reveals what struck the bell -- the shock wave from the sun."
This ringing of the plasma bell is what led to the key evidence showing Voyager had entered interstellar space. Because denser plasma oscillates faster, the team was able to figure out the density of the plasma. In 2013, thanks to the second tsunami wave, the team acquired evidence that Voyager had been flying for more than a year through plasma that was 40 times denser than measured before -- a telltale indicator of interstellar space.
Why is it denser out there? The sun's winds blow a bubble around it, pushing out against denser matter from other stars.
Now, the team has new readings from a third wave from the sun, first registered in March of this year. These data show that the density of the plasma is similar to what was measured previously, confirming the spacecraft is in interstellar space. Thanks to our sun's rumblings, Voyager has the opportunity to listen to the singing of interstellar space -- an otherwise silent place.
Voyager 1 and its twin, Voyager 2, were launched 16 days apart in 1977. Both spacecraft flew by Jupiter and Saturn. Voyager 2 also flew by Uranus and Neptune. Voyager 2, launched before Voyager 1, is the longest continuously operated spacecraft and is expected to enter interstellar space in a few years.
JPL, a division of Caltech, built and operates the twin Voyager spacecraft. The Voyagers Interstellar Mission is a part of NASA's Heliophysics System Observatory, sponsored by the Heliophysics Division of NASA's Science Mission Directorate in Washington. NASA's Deep Space Network, managed by JPL, is an international network of antennas that supports interplanetary spacecraft missions and radio and radar astronomy observations for the exploration of the solar system and the universe. The network also supports selected Earth-orbiting missions. The spacecraft's nuclear batteries were provided by the Department of Energy.
For more information on the Voyager mission, visit:
http://voyager.jpl.nasa.gov
Whitney Clavin (818) 354-4673
Jet Propulsion Laboratory, Pasadena, Calif.
[email protected]

http://www.nasa.gov/jpl/voyager/sun-sends-tsunami-waves-20140707/index.html#.U7xC7WK9KK0
« Last Edit: 07/08/2014 07:17 pm by Star One »

Offline Liss

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Re: NASA - Voyager 1 and 2 updates
« Reply #153 on: 07/09/2014 09:09 am »
Finally found the Launch Press Kit for Voyager 1 & 2. Enjoy :-)
« Last Edit: 03/05/2017 06:23 pm by Liss »
This message reflects my personal opinion based on open sources of information.

Offline Nomadd

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Re: NASA - Voyager 1 and 2 updates
« Reply #154 on: 11/01/2015 12:44 pm »
Talk about a seldom visited thread. Cassini, Opportunity and Odyssey get lots of press for their incredibly long lived missions, but this old girl humbles them all and still makes the news.

http://www.engadget.com/2015/10/31/study-answers-lingering-questions-about-voyager-1-in-interstella/
« Last Edit: 11/01/2015 12:47 pm by Nomadd »
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Offline jgoldader

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Re: NASA - Voyager 1 and 2 updates
« Reply #155 on: 11/02/2015 08:30 pm »
FWIW, Voyager 2's cosmic ray counts are doing very weird things the last couple of weeks.  Recent data for two channels are shown at http://voyager.gsfc.nasa.gov/heliopause/recenthist.html.  The high energy  (>70 MeV/nucleon) channel is dropping fast after a pretty constant rate of increase, and the low-energy channel is also dropping after a recent ~50% climb.  This is not like what V1 saw as it crossed the heliopause, but is pretty unusual; I watch the page frequently and don't remember seeing this behavior before.
Recovering astronomer

Offline YesRushGen

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Re: NASA - Voyager 1 and 2 updates
« Reply #156 on: 11/03/2015 01:27 pm »
Here is another recent article related to the Voyagers:

Why NASA Needs a Programmer Fluent In 60-Year-Old Languages

Offline LouScheffer

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Re: NASA - Voyager 1 and 2 updates
« Reply #157 on: 11/05/2015 02:32 pm »
A good question from a friend of mine....

If Voyager was made today, using today's technology, how long do you think you could keep it going, given Voyager is expected to power off completely in 10-15 years or so?
[...] Comms range might be the limit. New Horizons has a smaller and lower gain antenna than Voyager. Taking a wild-ass guess that the receiver is about 3db more sensitive than Voyager's, they should have about the same receive range. I don't know New Horizon's output power on the high gain dish so can't guess the transmit range.
The receive range for any deep space mission will almost never be the limiting factor.  Comparing uplink and downlink, the product of the two antenna gains and the free-space loss are identical (by reciprocity).  So you only need to compare receiver noise and transmit power.  The receiver on the spacecraft is not cryogenically cooled, so might have a noise temperature of 300K, perhaps 10x worse than the downlink receiver.  But the transmitter on the ground is about 1000x stronger than that on the spacecraft (20 KW vs 20 watts).  So overall the uplink margin should be about 100x the downlink margin.

And if you don't need fast data, the downlink ranges are really large.  Here'a an estimate by JPL showing that if they drop the data rate to 40 bits/sec, they can receive Voyager until 2057, on their smaller antennas (and in theory, they'd get twice this range with the bigger antenna, or an array of 4 smaller ones.).  http://descanso.jpl.nasa.gov/DPSummary/Descanso4--Voyager_new.pdf  .  So almost surely something else (like running out of power) will give out first.

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Re: NASA - Voyager 1 and 2 updates
« Reply #158 on: 10/03/2016 04:44 am »
Voyager 2 Saturn Flyby in 1981 (1986) NASA JPL (Jet Propulsion Laboratory)

Jeff Quitney

Published on Oct 1, 2016

"AL HIBBS, DR. EDWARD STONE, DR. BRAD SMITH, DR. DANIEL GAUTIER, AND DR. ANDRE BRAHIC, SCIENTISTS, JET PROPULSION LABORATORY, DISCUSS THE DISCOVERY OF NEW MOONS, ATMOSPHERIC COMPOSITION... SHOWS RECENT VOYAGER PHOTOGRAPHS."

Reupload of a previously uploaded film, in one piece instead of multiple parts, and with improved video & sound.

The Voyager 2 spacecraft is a 722-kilogram (1,592 lb) space probe launched by NASA on August 20, 1977 to study the outer Solar System and eventually interstellar space. Operating for 34 years, 7 months and 2 days as of today (22 March 2012), the spacecraft receives routine commands and transmits data back to the Deep Space Network.

Part of the Voyager program with its identical sister craft Voyager 1, the spacecraft is currently in extended mission, tasked with locating and studying the boundaries of the Solar System, including the Kuiper belt, the heliosphere and interstellar space. The primary mission ended December 31, 1989 after encountering the Jovian system in 1979, Saturnian system in 1980, Uranian system in 1986, and the Neptunian system in 1989. It was the first probe to provide detailed images of the outer gas giants...

Conceived in the 1960s, a Grand Tour proposal to study the outer planets, prompted NASA to begin work on a mission in the early 1970s. The development of the interplanetary probes coincided with an alignment of the planets, making possible a mission to the outer Solar System by taking advantage of the then-new technique of gravity assist.

It was determined that utilizing gravity assists would enable a single probe to visit the four gas giants (Jupiter, Saturn, Uranus, and Neptune) while requiring a minimal amount of propellant and a shorter transit duration between planets. Originally, Voyager 2 was planned as Mariner 12 of the Mariner program however, due to congressional budget cuts, the mission was scaled back to be a flyby of Jupiter and Saturn, and renamed the Mariner Jupiter-Saturn probes. As the program progressed, the name was later changed to Voyager as the probe designs began to differ greatly from previous Mariner missions.

Upon a successful flyby of the Saturnian moon Titan, by Voyager 1, Voyager 2 would get a mission extension to send the probe on towards Uranus and Neptune...

Spacecraft design

Constructed by the Jet Propulsion Laboratory, Voyager 2 included 16 hydrazine thrusters, three-axis stabilization, gyroscopes and celestial referencing instruments (Sun sensor/Canopus Star Tracker) to maintain pointing of the high-gain antenna toward Earth. Collectively these instruments are part of the Attitude and Articulation Control Subsystem (AACS) along with redundant units of most instruments and 8 backup thrusters. The spacecraft also included 11 scientific instruments to study celestial objects as it traveled through space.

Communications

Built with the intent for eventual interstellar travel, Voyager 2 included a large, 3.7-meter parabolic, high-gain antenna (see diagram) to transceive data with the Deep Space Network on Earth. Communications are conducted over the S-band (13 cm wavelength) and X-band (3.6 cm wavelength) providing bandwidth as high as 115.2 kilobits per second. When the spacecraft is unable to communicate with Earth, the Digital Tape Recorder (DTR) is able to record up to 62,500-kilobytes of data to later transmit when communication is reestablished.

Power

The spacecraft was built with 3 Multihundred-Watt radioisotope thermoelectric generators (MHW RTG). Each RTG includes 24 pressed plutonium oxide spheres and provide enough heat to generate approximately 157 watts of power at launch. Collectively, the RTGs supply the spacecraft with 470 watts at launch and will allow operations to continue until at least 2020...

Public domain film from the US National Archives, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.
The soundtrack was also processed with volume normalization, noise reduction, clipping reduction, and/or equalization (the resulting sound, though not perfect, is far less noisy than the original).



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Offline Liss

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Re: NASA - Voyager 1 and 2 updates
« Reply #159 on: 03/05/2017 06:40 pm »
There is a nice set of Voyager weekly status reports from January 1995 till January 2015 at http://voyager.jpl.nasa.gov/mission/weekly-reports/ .
I wonder if an archive of earlier weekly reports exists. Judging from the number #845 at the 6 Jan 1995 report, they started at launch in 1977 or soon after.
This message reflects my personal opinion based on open sources of information.

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