V’GER

From NASA

July 8, 2019

A New Plan for Keeping NASA’s Oldest Explorers Going

7-8voyager-annotated

This artist’s concept depicts one of NASA’s Voyager spacecraft, including the location of the cosmic ray subsystem (CRS) instrument. Both Voyagers launched with operating CRS instruments.

Credits: NASA/JPL-Caltech

Unannotated version

With careful planning and dashes of creativity, engineers have been able to keep NASA’s Voyager 1 and 2 spacecraft flying for nearly 42 years — longer than any other spacecraft in history. To ensure that these vintage robots continue to return the best science data possible from the frontiers of space, mission engineers are implementing a new plan to manage them. And that involves making difficult choices, particularly about instruments and thrusters.

One key issue is that both Voyagers, launched in 1977, have less and less power available over time to run their science instruments and the heaters that keep them warm in the coldness of deep space. Engineers have had to decide what parts get power and what parts have to be turned off on both spacecraft. But those decisions must be made sooner for Voyager 2 than Voyager 1 because Voyager 2 has one more science instrument collecting data — and drawing power — than its sibling.

After extensive discussions with the science team, mission managers recently turned off a heater for the cosmic ray subsystem instrument (CRS) on Voyager 2 as part of the new power management plan. The cosmic ray instrument played a crucial role last November in determining that Voyager 2 had exited the heliosphere, the protective bubble created by a constant outflow (or wind) of ionized particles from the Sun. Ever since, the two Voyagers have been sending back details of how our heliosphere interacts with the wind flowing in interstellar space, the space between stars.

Not only are Voyager mission findings providing humanity with observations of truly uncharted territory, but they help us understand the very nature of energy and radiation in space — key information for protecting NASA’s missions and astronauts even when closer to home.

Mission team members can now preliminarily confirm that Voyager 2’s cosmic ray instrument is still returning data, despite dropping to a chilly minus 74 degrees Fahrenheit (minus 59 degrees Celsius). This is lower than the temperatures at which CRS was tested more than 42 years ago (down to minus 49 degrees Fahrenheit, or minus 45 degrees Celsius). Another Voyager instrument also continued to function for years after it dropped below temperatures at which it was tested.

“It’s incredible that Voyagers’ instruments have proved so hardy,” said Voyager Project Manager Suzanne Dodd, who is based at NASA’s Jet Propulsion Laboratory in Pasadena, California. “We’re proud they’ve withstood the test of time. The long lifetimes of the spacecraft mean we’re dealing with scenarios we never thought we’d encounter. We will continue to explore every option we have in order to keep the Voyagers doing the best science possible.”

Voyager 2 continues to return data from five instruments as it travels through interstellar space. In addition to the cosmic ray instrument, which detects fast-moving particles that can originate from the Sun or from sources outside our solar system, the spacecraft is operating two instruments dedicated to studying plasma (a gas in which atoms have been ionized and electrons float freely) and a magnetometer (which measures magnetic fields) for understanding the sparse clouds of material in interstellar space.

Taking data from a range of directions, the low-energy charged particle instrument is particularly useful for studying the probe’s transition away from our heliosphere. Because CRS can look only in certain fixed directions, the Voyager science team decided to turn off CRS’s heater first.

Voyager 1, which crossed into interstellar space in August 2012, continues to collect data from its cosmic ray instrument as well, plus from one plasma instrument, the magnetometer and the low-energy charged particle instrument.

Why Turn Off Heaters?

Launched separately in 1977, the two Voyagers are now over 11 billion miles (18 billion kilometers) from the Sun and far from its warmth. Engineers have to carefully control temperature on both spacecraft to keep them operating. For instance, if fuel lines powering the thrusters that keep the spacecraft oriented were to freeze, the Voyagers’ antennae could stop pointing at Earth. That would prevent engineers from sending commands to the spacecraft or receiving scientific data. So the spacecraft were designed to heat themselves.

But running heaters — and instruments — requires power, which is constantly diminishing on both Voyagers.

Each of the probes is powered by three radioisotope thermoelectric generators, or RTGs, which produce heat via the natural decay of plutonium-238 radioisotopes and convert that heat into electrical power. Because the heat energy of the plutonium in the RTGs declines and their internal efficiency decreases over time, each spacecraft is producing about 4 fewer watts of electrical power each year. That means the generators produce about 40% less than what they did at launch nearly 42 years ago, limiting the number of systems that can run on the spacecraft.

The mission’s new power management plan explores multiple options for dealing with the diminishing power supply on both spacecraft, including shutting off additional instrument heaters over the next few years.

Revving Up Old Jet Packs

Another challenge that engineers have faced is managing the degradation of some of the spacecraft thrusters, which fire in tiny pulses, or puffs, to subtly rotate the spacecraft. This became an issue in 2017, when mission controllers noticed that a set of thrusters on Voyager 1 needed to give off more puffs to keep the spacecraft’s antenna pointed at Earth. To make sure the spacecraft could continue to maintain proper orientation, the team fired up another set of thrusters on Voyager 1 that hadn’t been used in 37 years.

Voyager 2’s current thrusters have started to degrade, too. Mission managers have decided to make the same thruster switch on that probe this month. Voyager 2 last used these thrusters (known as trajectory correction maneuver thrusters) during its encounter with Neptune in 1989.

Many Miles to Go Before They Sleep

The engineers’ plan to manage power and aging parts should ensure that Voyager 1 and 2 can continue to collect data from interstellar space for several years to come. Data from the Voyagers continue to provide scientists with never-before-seen observations of our boundary with interstellar space, complementing NASA’s Interstellar Boundary Explorer (IBEX), a mission that is remotely sensing that boundary. NASA is also preparing the Interstellar Mapping and Acceleration Probe (IMAP), due to launch in 2024, to capitalize on the Voyagers’ observations.

“Both Voyager probes are exploring regions never before visited, so every day is a day of discovery,” said Voyager Project Scientist Ed Stone, who is based at Caltech. “Voyager is going to keep surprising us with new insights about deep space.”

The Voyager spacecraft were built by JPL, which continues to operate both. JPL is a division of Caltech in Pasadena. The Voyager missions are a part of the NASA Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate in Washington. For more information about the Voyager spacecraft, visit:

https://www.nasa.gov/voyager

https://voyager.jpl.nasa.gov

67 thoughts on “V’GER

    • Back when we could afford to build stuff to last, now called over design and too expensive.

    • Yes, last long enough to reach the planet of the machines where V’GER will be outfitted to search for its mommy and endanger planet earth. And you thought global changie-change was bad.

    • Back in the 70’s when these things were built, we had precious little data on deep space environments effects on materials. Because of this ‘margin’ was incorporated into the designs. For those unfamiliar with the engineering term, “margin” is essentially the error margin (in material properties: strength, thermal, etc.) one can attribute to the measured data, and any other conservatism added to account for manufacturing deviations.
      In short, margin, allowed the designs to be by analyses to be “overdesigned” by an expected error band. Space hardware is required to work in the most extreme (worse superimposed upon worse) conditions predicted. Normal operation is therefore benign. As is often the case most of the potential problems did not materialize nor superimpose upon one another to reach the expected margins. But, because many of the environments were unknown and as yet unmeasured, including margin was deemed prudent.

      With any space hardware you do not get a second chance. Performance often will take precedent over a few extra ounces of margin. Are we better now, absolutely. But, only because we have continued to experiment and have learned where to adjust the margins safely.

      • The ‘no second chance’ was especially true of the Voyager missions, which took advantage of a perfect alignment of the planets to slingshot past all the gas giants. Such a chance won’t come again for a long time yet.

    • The Voyager probes were somewhat surreptitiously overdesigned by people who realized they might be useful far longer than the mission plan called for.

      I’m far more impressed with the performance of the Martian rovers Spirit and Opportunity because they had far more mechanical activity to do. Opportunity lasted 60X the original mission’s goal. Pretty awesome machine to survive so long in a rather inhospitable environment.

      Compare current space probe missions to Voyager – Voyager was launched from Earth directly toward its goal. Pretty much all recent probes have taken circuitous paths past planets like Venus and Jupiter to pick up speed from slingshot trajectories. This adds years to the primary mission, yet the designers are confident the probes will last that long.

      Don’t criticize current missions when you haven’t presented evidence that they are about to fail.

    • No way to transport goods sustainable on raylways there’s fossil fuel guzzling trucks needed to deliver just in time.

  1. The Voyagers and the way NASA continue to control them to provide data never fails to leave me awestruck. It must rank as one of mankind’s greatest achievements.

    • A gold plaque was placed inside Voyager 1, pictographically etched with various information about Earth and humanity, just in case at some point in the distant future, the long-defunct craft would be encountered by extraterrestrials.

  2. Great to hear the Ed Stone is still in charge (or at least still part of the team)!

    • Vestiges from a time when we invested in science rather than subsistence welfare for 50 million.

      • Far beyond “subsistence” welfare. Show me a section 8 household (subsidized housing) without cable TV to a HD flat panel TV with every member of the family having a smart phone.

        Where I live, Las Vegas, NV, there are no longer any government housing with only evaporative coolers for the summer, they all now have air conditioners. There ARE still houses without AC that working poor live in, you know the people paying taxes to fund the welfare state. I lived in a house with only evaporative cooling for years while working my way up the income ladder, although at that time almost all of the government housing was also cooled that way. (35 years ago)

        About 10 years back the Las Vegas Housing Authority built new government single family housing that even included GARAGES! Now that is some subsistence!

        • So many evaporative coolers were operating in Vegas at one point that the relative humidity of the city started increasing, reducing the coolers’ effectiveness and turning dry desert heat into even more unpleasant wet heat. I expect this was a major reason the government housing switched to ACs.

      • Sal: The whole world has benefitted greatly. Spinoff electronic development makes these early investments cheap.

        Why is it you didnt touch on idiots throwing away trillions on a non problem like climate change. The destruction of economies and the deaths of hundreds of millions of peoples by marxy environmentalists makes space exploration look like chump change. What about the welfare of those unfotunates? To you, my question is purely rhetorical.

    • Or Barack Obama: Nasa must try to make Muslims ‘feel good’

      NASA administrator Charles Bolden said Obama told him one of his top priorities was to “find a way to reach out to the Muslim world and engage much more with dominantly Muslim nations to help them feel good about their historic contribution to science, math and engineering.”

      • Well they did put together what the Greeks left after Alexandria was sacked by the Persians and then Romans.

  3. Space is lovely, dark and deep,
    But they have missions to keep,
    And miles to go before they sleep,
    And miles to go before they sleep.

    with apologies to Robert Frost

    • My little probe must think it queer
      to wander through the dark out here,
      striving to keep its systems hot,
      and point its dish at a little dot…

      • I never refer to my probe as … little. But I was thoroughly entertained by your verse!

    • Oh, dear
      Wot’s That outside me now?
      So dark and cold and eerie

      Must be
      Outer space wi’ mysteries enow
      To keep me from gettin’ weary

  4. For semiconductors to last 42 years in such a harsh environment is insanely fantastic. If the the mission had been started one or two decades later, the amount of semiconductors would likely have been thousandths more, with a statistical larger chance of failure.

    Had they been sent off today, the greens would probably have demanded that the twins were powered by solar panels, thus would have been almost as useful as the industrial scale wind turbines. /SARC

    • Had they set off today, it would take another 42 years to travel four light-hours.

    • Interestingly the older semiconductors probably fare better because the traces are so thick, they are less likely to be affected by cosmic radiation and various stresses that newer 14 nanometer circuits could not cope with.

      In fact in around 2005 there was significant worry about single neutron events affecting commercial airplane components, because the traces were so small it was much easier to change the polarity of the transistors. This caused problems even with the ECC memory and triple redundant circuitry. The effect didn’t happen often, but often enough to be a concern.

    • There’s a solar “wind”.
      That means they would have demanded the solar panels be mounted on the solar windmill vanes or they would glue themselves to something.

      • Shhhhh, or some green moron will demand government investment in solar wind farms.

      • They can’t install solar wind farms unless there’s no more enough solar wind to produce enough radiation for plasmatising Earth’s dark side atmosphere.

        Correct me where I’m wrong.

    • Had they been sent off w/i the past 15 years, greens would have protested the radioactive 9 volt batteries on board. They would have claimed if an accident occurred during launch, the whole planet would be un-inhabitable due to a global winter.
      Note, not entirely sarcastic…

  5. Minus 74 degrees F? Much warmer than I would have thought. According to Wikipedia “the lowest natural temperature ever directly recorded at ground level on Earth is −89.2 °C (−128.6 °F; 184.0 K) at the Soviet Vostok Station in Antarctica on 21 July, 1983 by ground measurements.”

    • Space systems are tested in cryogenic vacuum chambers here on Earth. We have 2 such test chambers. The large (30 foot diameter) spherical chambers are pump evacuated to near vacuum and cryogenically cooled to -270° C. This process takes several days if not over a week to thermally chill all the structure and the test article (satellite, space telescope, etc.) down to cold soak temperatures. In addition the test set-up must include “radiation absorber panels” placed near any radiation devices (antennas, solar panels) to account for emitted radiation which could effect the tests. Often we are testing heat rejection systems (radiator panels) to allow the spacecraft to properly control its heat budget and not overheat sensors because even minute heating from electronic components can cause issues. But, as we travel more into deep space keeping things warm becomes the driving requirement.

  6. “One key issue is that both Voyagers, launched in 1977, have less and less power available over time to run their science instruments and the heaters that keep them warm in the coldness of deep space.”

    Space – the Hotter Frontier

    One of the heated issues underlying greenhouse theory is whether space is hot or cold.

    Greenhouse theory says that without an atmosphere the earth would be exposed to a near zero outer space and become a frozen ice ball at -430 F, 17 K.

    Geoengineering techniques that increase the albedo, the ISS’s ammonia refrigerant air conditioners, an air conditioner in the manned maneuvering unit, space suits including thermal underwear with chilled water tubing, UCLA Diviner lunar data and Kramm’s models (Univ of AK) all provide substantial evidence that outer space is relatively hot.

    But outer space is neither hot nor cold.

    By definition and application temperature is a relative measurement of the molecular kinetic energy in a substance, i.e. solid, liquid, gas. No molecules (vacuum), no temperature. No kinetic energy (absolute zero), no temperature. In the void & vacuum of outer space the terms temperature, hot, cold are meaningless, like dividing by zero, undefined. Same reason there is no sound in space – no molecules.

    However, any substance capable of molecular kinetic energy (ISS, space walker, satellite, moon, earth) placed in the path of the spherical expanding solar photon gas at the earth’s average orbital distance will be heated per the S-B equation to an equilibrium temperature of: 1,368 W/m^2 = 394 K, 121 C, 250 F.

    Like a blanket held up between a camper and campfire the atmosphere reduces the amount of solar energy heating the terrestrial system and cools the earth compared to no atmosphere.

    This intuitively obvious as well as calculated and measured scientific reality refutes the greenhouse theory.

    Zero greenhouse effect, Zero CO2 global warming and Zero man caused climate change.

    Since the earth is actually hot without an atmosphere, radiative greenhouse effect goes straight into the historical trash bin of failed theories and all the handwavium, pseudo-science, thermodynamic nonsense pretending to explain it follows close behind.

    • Nick, as with all environments we wish to control we must include energy budgets. “Space” has no substance or mass and therefore no “temperature”. What space does have is an infinite heat sink to which any body may radiate its own energy. Hopefully you won’t encounter convective heat transfer in space, because that means you’ve collided with something. The items traveling through space do have mass and substance and therefore do have measurable temperature. These items will either act as heat sources or heat sinks depending on whether they have more or less thermal energy than you do.
      Space near a star like our sun has considerable thermal radiation from that source, but only during direct exposure. The side facing the sun gets hot, the other side is radiating to deep space and quite cold. Additionally the spacecraft or astronaut generates its own heat which must be controlled. That’s why special thermal undergarments are worn by astronauts to both keep them from overheating and to keep the hot side from cooking and cold side from freezing. Satellites use similar heat transport systems such as heat pipes and radiator panels.

      • Rs, what’s the signal strength these days from the Voyagers, from 11 billion miles out?

        PicoWatts? 🙂

        • I worked that out about two years ago, so it will be a bit less than this.

          I figured -124 dBm, which is about 0.4 femtowatt (.0004 picowatt). It will be less today, but distance has to double to drop it by 6dB (1/4 of that power) so “less than 1/2 femtowatt” is probably all the significant digits I can justify.

        • 50w. That all. Less than an incandescent bulb. That signal travels for OWLT (One way light time) 20:10 and 16:40 [HH:MM] for Voyager 1 and 2 respectively. The Voyagers signals are received by the Deep Space Network’s 37 meter dishes.

          I’m former operations at JPL.

      • I inherited a computer in the early 1990’s, which was late 1980’s, and it was a kludge.

    • I maintain a 1940s transmitter at a museum that still keeps its vacuum tubes and Mercury vapour rectifiers glowing nicely, but not fully operational. Probably would run ok if I fully fired it up though. Occasionally I power up other very old electronic gear.

    • The software that put men on the moon can fit on a 1.44mb floppy disk with room to spare. 🙂

  7. Radio message recently received by NASA from Alpha Centauri:

    Dear Earthlings,

    We have just encountered your space probes Voyagers 1 and 2. We found the gold records included in them quite interesting and we wish to congratulate you on the progress your species is making in space exploration. We have been carefully monitoring your radio and television transmissions for over fifty years now and we are quite impressed with the rapid advances that you making. But if you persist in broadcasting old re-runs of Gilligan’s Island we will have no choice but to destroy your planet.

    Cordially,
    Alpha Centauri

  8. With the ability to launch bigger payloads today, I’m wondering why we don’t consider another deep space probe that would be bigger, faster and more capable. If we launched the probe in parts and assembled it in space, the resultant probe could better and more sophisticated sensors and attain a higher speed on launch and possibly include ion drives to accelerate it even more.

    It could do the planet flybys and answer some questions that came up from Voyager and the other probes. Since it takes so long to get these devices even to the edge of our solar system, to me it makes sense to launch it sooner than later.

    • Might be cheaper to launch much smaller single purpose drone-like travelers to the outer reaches of our world. Smaller is likely to be sturdier.

    • We have.
      New Horizons
      https://www.nasa.gov/feature/nasa-s-new-horizons-team-publishes-first-kuiper-belt-flyby-science-results
      And an interesting tid-bit on New Horizons: About 30 grams (1 oz) of Clyde Tombaugh’s ashes are aboard the spacecraft, to commemorate his discovery of Pluto in 1930. A Florida-state quarter coin, whose design commemorates human exploration, is included, officially as a trim weight.

      All Planetary exploration probes so far on extra-solar system trajectories:

      – Pioneer 10 – launched in 1972, flew past Jupiter in 1973 and is heading in the direction of Aldebaran (65 light years away) in the constellation of Taurus. Contact was lost in January 2003, and it is estimated to have passed 120 AU.

      – Pioneer 11 – launched in 1973, flew past Jupiter in 1974 and Saturn in 1979. Contact was lost in November 1995, and it is estimated to be at around 100 AU. The spacecraft is headed toward the constellation of Aquila, northwest of the constellation of Sagittarius. Barring an incident, Pioneer 11 will pass near one of the stars in the constellation in about 4 million years.

      Voyager 2 – launched in August 1977, flew past Jupiter in 1979, Saturn in 1981, Uranus in 1986, and Neptune in 1989. The probe left the heliosphere for interstellar space at 119 AU on 5 November 2018. Voyager 2 is still active. It is not headed toward any particular star, although in roughly 40,000 years it should pass 1.7 light-years from the star Ross 248. If undisturbed for 296,000 years, it should pass by the star Sirius at a distance of 4.3 light-years.

      – Voyager 1 – launched in September 1977, flew past Jupiter in 1979 and Saturn in 1980, making a special close approach to Saturn’s moon Titan. The probe passed the heliopause at 121 AU on 25 August 2012 to enter interstellar space.Voyager 1 is still active. It is headed towards an encounter with star AC +79 3888, which lies 17.6 light-years from Earth, in about 40,000 years. Voyager 1 has the highest solar system escape velocity of all the current missions. As a result none of the other probes launched so far will ever pass it in terms of distance from the Sun.

      New Horizons – launched in 2006, the probe flew past Jupiter in 2007 and Pluto on 14 July 2015. It flew past the Kuiper belt object (486958) 2014 MU69 (nicknamed Ultima Thule) on January 1, 2019, as part of the Kuiper Belt Extended Mission (KEM).

      source: https://en.wikipedia.org/wiki/List_of_artificial_objects_leaving_the_Solar_System

  9. Just think, this thing will still be flying after the sun goes to red giant stage and the earth is consumed. Even though space is immense, perhaps someone with extremely accurate scanning equipment will spot it as part of their concerted effort to track asteroid risk–after determining that was a wiser use of resources than global warming from trace gases.

  10. The ‘technological advancement’ of mankind is akin to an 8 month old babe peering out of his cradle and trying to make sense of a mobile of the moon, planets, sol, and a billion stars beckoning over his head. Hear his gurgling chuckles of delight, as his inquisitive wee hands reach upwards……

    First, we learn to crawl. Then, we learn to walk. Finally, we learn to run.
    It’s what we do. It’s who we are. Our future is beyond the cradle of Earth.

  11. A Solar Power Satellite could be used to propel small space probes to extremely high speeds.

    The Pioneer and Voyager spacecraft may not be the farthest from Earth in the not-too-distant future.

  12. The last news I heard was that these oldtimers had stopped working about a decade or more ago.

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