Engineers shut down one science instrument on Voyager-2 to conserve power
In order to keep the spacecraft functioning as its nuclear power source dwindles, engineers have now shut down one of Voyager-2’s operating science instruments in order to keep four instruments operating.
Mission engineers at NASA have turned off the plasma science instrument aboard the Voyager 2 spacecraft due to the probe’s gradually shrinking electrical power supply.
Traveling more than 12.8 billion miles (20.5 billion kilometers) from Earth, the spacecraft continues to use four science instruments to study the region outside our heliosphere, the protective bubble of particles and magnetic fields created by the Sun. The probe has enough power to continue exploring this region with at least one operational science instrument into the 2030s. [emphasis mine]
The highlighted sentence is the first time I have ever seen any prediction for the life of Voyager-2 to extend past 2030. Previously, project engineers have consistently stated that the power would run down sometime around 2026. This extension suggests the decision has been made to do whatever can be done to keep the spacecraft functioning for as long as possible, not so much to do science but to test the limits of its engineering. To do so, they will step-by-step shut down instruments rather than keep them all going.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
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In order to keep the spacecraft functioning as its nuclear power source dwindles, engineers have now shut down one of Voyager-2’s operating science instruments in order to keep four instruments operating.
Mission engineers at NASA have turned off the plasma science instrument aboard the Voyager 2 spacecraft due to the probe’s gradually shrinking electrical power supply.
Traveling more than 12.8 billion miles (20.5 billion kilometers) from Earth, the spacecraft continues to use four science instruments to study the region outside our heliosphere, the protective bubble of particles and magnetic fields created by the Sun. The probe has enough power to continue exploring this region with at least one operational science instrument into the 2030s. [emphasis mine]
The highlighted sentence is the first time I have ever seen any prediction for the life of Voyager-2 to extend past 2030. Previously, project engineers have consistently stated that the power would run down sometime around 2026. This extension suggests the decision has been made to do whatever can be done to keep the spacecraft functioning for as long as possible, not so much to do science but to test the limits of its engineering. To do so, they will step-by-step shut down instruments rather than keep them all going.
On Christmas Eve 1968 three Americans became the first humans to visit another world. What they did to celebrate was unexpected and profound, and will be remembered throughout all human history. Genesis: the Story of Apollo 8, Robert Zimmerman's classic history of humanity's first journey to another world, tells that story, and it is now available as both an ebook and an audiobook, both with a foreword by Valerie Anders and a new introduction by Robert Zimmerman.
The print edition can be purchased at Amazon or from any other book seller. If you want an autographed copy the price is $60 for the hardback and $45 for the paperback, plus $8 shipping for each. Go here for purchasing details. The ebook is available everywhere for $5.99 (before discount) at amazon, or direct from my ebook publisher, ebookit. If you buy it from ebookit you don't support the big tech companies and the author gets a bigger cut much sooner.
The audiobook is also available at all these vendors, and is also free with a 30-day trial membership to Audible.
"Not simply about one mission, [Genesis] is also the history of America's quest for the moon... Zimmerman has done a masterful job of tying disparate events together into a solid account of one of America's greatest human triumphs."--San Antonio Express-News
As the Voyagers traverse the outer boundaries of the Solar system, it makes sense to keep scientific data coming as long as possible in order to cover areas as far out as possible.
Thus, I am puzzled that the extension is deemed to be “… not so much to do science but to test the limits of its engineering.”
The scientific value of probing further outward seems indisputable, but I am less convinced of the value of studying the engineering limits of 47-year-old technology. Can you clarify your thinking?
Ray Van Dune: What I know is that before they were going to keep as many science instruments functioning for as long as possible, but that would cause power to run out by c2026. Now it appears they are going to shut down those instruments one-by-one so that they can extend the spacecraft life.
To me, this means they have shifted priority from science to engineering. Whether that shift makes sense however is another question — one that you quite correctly raise.
Maybe I’m the confused one, but given Voyager‘s power source, which converts radioactive decay by-products into electricity, you’d expect the power available to constantly decline. For instance, if your radioactive material has a half-life of ten years, after ten years it produces half as much power, and it’s down to a quarter the power after twenty.
Ancient battery tech or no, you’re mostly in a use-it-or-lose-it situation, because the radioactive material decays whether or not you’re using the electricity. Just as importantly, you can’t use up the radioactives faster to generate more electricity but a shorter lifespan.
I’d suggest that it’s more that they have a finer understanding of the decreasing, useful output of the power source than they once did.
With the decay rate of Pu-238 in the RTGs, it is down to 225 watts.
It can be testing the limits of Earth-bound engineering. A maximum of 225 watts from 20.5 billion km away can’t be much of a signal.
The Voyagers use a 23W radio that transmit a downlink back to Earth at two different frequencies-
Voy-1: 2296/8420 MHz
Voy-2: 2295/8415 MHz
The uplink from Earth to the Voyagers via the DSN uses 400kW-
Voy-1: 2114.6 MHz
Voy-2: 2113.3 MHz
Remember that those DSN dishes are 70 meters in diameter and have a gain of 48dbi. Not only that but they are the pioneers of weak signal processing at the receiver end.
Jay: Based on these numbers, it will be a significant engineering achievement to maintain communications with the spacecraft for as long as possible, and will provide good information for later missions to similar distances.
The late 70’s era technology is likely perfect for such missions…not as primitive as Apollo tech or as vulnerable as modern chips–tight programming, etc.
The one instrument, of course, that cannot be turned off, is the radio.