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Post by swamprat on Nov 4, 2019 21:47:01 GMT
NASA's Voyager Spacecraft May Have 5 Years Left to Explore Interstellar Space
By Meghan Bartels | Nov. 4, 2019
An artist's visualization of NASA's Voyager 1 spacecraft. (Image: © NASA/JPL-Caltech)
The twin Voyager probes are the ultimate spaceflight overachievers, but everyone knows their run can't last forever.
Right now, it's looking like the grizzled spacefarers have about five years before they fall silent, when they'll be no longer able to send word of their adventures back to the humans who have eagerly awaited their telegrams for 42 years and counting. The Voyagers' journey will continue indefinitely, but we will no longer travel with them.
"It's cooling off, the spacecraft is getting colder all the time and the power is dropping," Ed Stone, the mission's project scientist and a physicist at Caltech, said during a news conference held Oct. 31 in conjunction with the publication of a handful of new scientific papers. "We know that somehow, in another five years or so, we may not have enough power to have any scientific instruments on any longer."
Their success is unprecedented, even by NASA standards; the mission has lasted for two-thirds of the agency's existence. "We're certainly surprised but also wonderfully excited by the fact that they do [still work]," Stone said. "When the two Voyagers were launched, the Space Age was only 20 years old, so it was hard to know at that time that anything could last over 40 years."
Just as stunning as the spacecraft's longevity has been the longevity of a handful of instruments on board the probes. Four instruments on Voyager 1 continue to work; their twins and a fifth instrument are still gathering data on Voyager 2.
Stamatios Krimigis, a space scientist at the Johns Hopkins University Applied Physics Laboratory and the principal investigator of the mission's low-energy charged particles experiment, explained that the devices were designed to last just four years, during which they would need to conduct 250,000 turns of a motor (dubbed "steps") to take measurements. Both versions of the experiment are still running.
"That device has been stepping every 192 seconds for the last 42 years," Krimigis said during the news conference. "It's close to 8 million steps, and we're absolutely amazed that it's still working."
The Voyager spacecraft launched two weeks apart in 1977, taking slightly different trajectories past Jupiter and Saturn. Then, the probes parted ways. Voyager 1 scouted out Saturn's moon Titan and then made a beeline out of our solar system; Voyager 2 took a more leisurely route, giving humans our only look at Uranus and Neptune.
Their longevity has translated to speed and distance that are difficult to fathom. Both spacecraft are traveling at more than 30,000 mph (48,000 km/h). On NASA's tracking page for the mission, each spacecraft's odometer ticks up by 10 miles (16 kilometers) or more twice a second, a constant churn that makes the passage of time suddenly excruciating.
But the Voyagers are traveling at nowhere near the speed of light (186,000 mps, or 300 million km/s), as their messages do. And yet, it takes nearly 17 hours for messages from Voyager 2 to travel back to Earth and more than 20 hours for those sent by Voyager 1. A whole meme cycle can roil the internet here on Earth between a message's dispatch and its arrival.
The probes' distance only makes them more compelling emissaries. A year ago, the mission checked off yet another achievement when Voyager 2 followed its twin through the bubble that surrounds our solar system. In just a couple of hours, Voyager 2 went from being surrounded by material born in the sun to being bathed by the local neighborhood — a transition Voyager 1 had made in 2012.
Stone and Krimigis spoke to mark the publication of the first batch of scientific papers comparing the two crossings. The twin spacecraft's transitions to interstellar space have been similar but not identical, variations on a theme that humans have no concrete plans to experience again anytime soon. Unless something very dramatic happens in the universe around us, Pluto veteran New Horizons, like the Pioneer spacecraft before it, will fall silent long before it escapes our little bubble.
What the Voyager mission has made clear, the scientists speaking at the news conference said, is that two crossings are hardly enough to begin understanding this bubble — and that, nevertheless, the spacecraft have completely changed what we know about it.
"We had no good quantitative idea of how big this bubble is that the sun creates around itself," Stone said. "We didn't know how large the bubble was, and we certainly didn't know that the spacecraft could live long enough to reach the edge of the bubble and leave the bubble and enter interstellar space, at least nearby interstellar space."
And now, of course, they do.
"This has really been a wonderful journey," Stone said.
www.space.com/voyager-spacecraft-lose-power-in-5-years.html
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Post by swamprat on Nov 5, 2019 16:52:09 GMT
Voyager 2's Trip to Interstellar Space Deepens Some Mysteries Beyond Our Solar System
By Mike Wall | Nov. 4, 2019 | Science & Astronomy
The boundary region between the sun's sphere of influence and the broader Milky Way galaxy is complicated indeed.
NASA’s Voyager 2 spacecraft entered interstellar space in November 2018, more than six years after its twin, Voyager 1, did the same. Data from Voyager 2 has helped further characterize the structure of the heliosphere, the huge bubble the sun blows around itself. (Image: © NASA /JPL-Caltech)
Humanity's second taste of interstellar space may have raised more questions than it answered.
NASA's Voyager 2 spacecraft popped free of the heliosphere — the huge bubble of charged particles that the sun blows around itself — on Nov. 5, 2018, more than six years after the probe's pioneering twin, Voyager 1, did the same.
The mission team has now had some time to take stock of Voyager 2's exit, which occurred in the heliosphere's southern hemisphere (as opposed to Voyager 1, which departed in the northern hemisphere). In a series of five papers published online today (Nov. 4) in the journal Nature Astronomy, the researchers reported the measurements made by the probe as it entered interstellar space.
These data are full of surprises. For example, Voyager 2 traversed the heliopause — the boundary between the heliosphere and interstellar space — when the probe was 119 astronomical units (AU) from the sun. (One AU is the average Earth-sun distance, which is about 93 million miles, or 150 million kilometers.) Voyager 1 made the crossing at nearly the same distance, 121.6 AU.
This consistency is "very strange, in the sense that one [Voyager 2's crossing] occurred at the solar minimum, when the solar activity is the least, and the other one occurred at the solar maximum," Stamatios Krimigis, lead author of one of the new Voyager 2 papers, said during a teleconference with reporters last week, referring to the sun's 11-year activity cycle.
"If we take our models at face value, we expected that there would be, indeed, a difference," added Krimigis, who's based at the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, and the Office of Space Research and Technology at the Academy of Athens in Greece.
Voyager project scientist Ed Stone, of the California Institute of Technology in Pasadena, also emphasized the dynamism of the solar bubble. "The heliosphere itself is breathing in and out," he said during the same teleconference.
In addition to the large-scale expansion and contraction noted by Krimigis, Stone said, there are shorter-term heliospheric perturbations caused by coronal mass ejections, powerful explosions that blast huge amounts of solar plasma out into space.
"It's a very complicated interaction that's going on that we're studying," said Stone, who led one of the new studies and co-authored another one.
Voyager 2's measurements of the interstellar magnetic field are also intriguing. "Before Voyager 1's 2012 crossing, the team expected to see significant differences in the direction of the magnetic field outside the heliosphere compared to the one inside," said Leonard Burlaga of
NASA's Goddard Space Flight Center in Maryland.
But Voyager 1 found that the interstellar field was largely aligned with the heliospheric field — and so did Voyager 2, we learned today. So this appears to be a real phenomenon, not some fluky coincidence.
"We have to come to some understanding of why the magnetic field doesn't change," Burlaga, the lead author of one of the new Nature Astronomy papersand a co-author on another one, said in the telecon.
"There must be some process causing the alignment," he added, and "that process is simply not understood."
Then there's the "leakage" observed by both spacecraft. Voyager 1 detected interstellar particles on two separate occasions as it neared the heliopause, and the mission team has attributed that finding to two intruding "interstellar flux tubes." But Voyager 2's experience was quite the opposite: The probe detected some solar particles for a while after it left the heliosphere.
The difference may have something to do with heliospheric geometry, given that Voyager 1 and Voyager 2 left the solar bubble in very different places. "But we don't really know the answer to that," Krimigis said.
There are other differences reported by the two probes as well. For example, Voyager 1 observed that the speed of the solar wind — the stream of charged particles flowing continuously from the sun, "inflating" the heliosphere — dropped nearly to zero close to the heliopause. But Voyager 2 measured relatively high solar-wind speeds almost all the way through until crossing. And Voyager 2's data suggest a smoother and thinner heliopause than that observed by Voyager 1 (though both spacecraft apparently traversed the boundary in less than a day).
A long ride nears the end
Voyager 1 and Voyager 2 launched a few weeks apart in 1977, tasked with performing an unprecedented "grand tour" of the solar system's giant planets. Voyager 1 flew by Jupiter and Saturn; Voyager 2 did the same but then zoomed past Uranus and Neptune as well.
After Voyager 2's Neptune encounter, which occurred in August 1989, the two spacecraft entered a new phase known as the Voyager Interstellar Mission. They would journey on into the distant unknown, lighting up the darkness as they flew.
And that darkness was nearly total at the time; very little was known about the heliosphere's outer reaches.
"We didn't know how large the bubble was," Stone said. "And we certainly didn't know that the spacecraft could live long enough to reach the edge of the bubble and leave the bubble and enter interstellar space."
(A quick note here: Entering interstellar space is not the same thing as leaving the solar system, because the sun's gravitational influence extends far beyond the heliosphere. Indeed, trillions of comets orbit in the Oort Cloud, thousands of AU from the sun, and they're still considered part of the solar system.)
But the Voyagers are nearing the end of the line. Each spacecraft is powered by three radioisotope thermoelectric generators (RTGs), which convert to electricity the heat generated by the radioactive decay of plutonium-238. The RTGs' power output decreases over time as more and more of the plutonium decays.
The mission team has already taken steps to squeeze the most out of the remaining nuclear fuel, turning off certain heaters and scientific instruments over time to lower the power needs. (Voyager 2 retains five working instruments out of its original 10, but Voyager 1 is down to four; its plasma spectrometer failed in 1980.) "But there aren't many more such levers to pull, so each Voyager can probably collect and return data for just five more years or so," Stone said.
Those five years could end up being very productive, potentially revealing key characteristics of the "true" interstellar medium — the vast region beyond the tangled and complicated swath near the heliosphere, where our solar bubble exerts considerable influence.
For example, "as we move further away, will we see the [magnetic] field outside slowly but surely sort of twist and turn to relax to an unperturbed state, which is what's farther away?" Stone said. "How far can we get from the heliosphere and measure the Milky Way galaxy without the perturbation of the heliosphere changing it?"
Other important questions may be answered only with the launch of new missions. For example, we still don't know the shape of the heliosphere, whether it's roughly spherical or has a long, comet-like tail. Both Voyagers popped free from the "head" of the heliosphere, the leading edge that's plowing through the interstellar medium on our solar system's long orbit around the center of the Milky Way.
"We would certainly like to have a spacecraft go down the tail, if it exists," said Don Gurnett of the University of Iowa, the lead author of one of the new Nature Astronomy papers. "But, of course, the tail might be really long — I mean, hundreds of AU."
Voyager 1 and Voyager 2 are currently about 148 AU and 122.4 AU from Earth, respectively, and 160 AU from each other. The next-most-distant operational spacecraft, NASA's New Horizons Pluto probe, is just over 46 AU from our planet at the moment.
"And we shouldn't bank on interstellar data from New Horizons; that spacecraft will likely run out of power by the time it's about 90 AU away," Krimigis said. (But New Horizons will keep gathering interesting data about the Kuiper Belt, the ring of objects beyond Neptune, well into the future. The spacecraft has already performed two flybys in the region — one of Pluto and one of the small body 2014 MU69 — and has enough fuel for another encounter if NASA greenlights another mission extension, New Horizons team members have said.)
www.space.com/nasa-voyager-2-interstellar-space-mysteries.html
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Post by Deleted on Dec 30, 2019 6:40:30 GMT
I've studied heliophysics now as an amateur for several years. It only seems to get more and more complicated...The more I learn, the less I seem to know.....  |
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Post by SysConfig on Dec 30, 2019 9:25:39 GMT
I've studied heliophysics now as an amateur for several years. It only seems to get more and more complicated...The more I learn, the less I seem to know..... great stuff Cliff..the heliosphere appears to be breathing in and out...maybe the Sun worshippers were on to something..let's hope it doesn't tire of the carbon based units on Earth.. |
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Post by Deleted on Dec 31, 2019 0:50:31 GMT
We are aliens  Calculating the time it will take spacecraft to find their way to other star systems
December 27, 2019 by Bob Yirka, Phys.org A pair of researchers, one with the Max Planck Institute for Astronomy, the other with the Jet Propulsion Laboratory at CIT, has found a way to estimate how long it will take already launched space vehicles to arrive at other star systems. The pair, Coryn Bailer-Jones and Davide Farnocchia have written a paper describing their findings and have uploaded it to the arXiv preprint server. Back in the 1970s, NASA sent four unmanned space probes out into the solar system—Pioneer 10 and 11, and Voyager 1 and 2—which, after completion of their missions, kept going—all four are on their way out of the solar system or have already departed. But what will become of them? Will they make their way to other star systems, and if so, how long might it take them? This is what Bailer-Jones and Davide Farnocchia wondered. To find some possible answers, they used the Gaia space telescope. It was launched by the European Space Agency back in 2013 and has been stationed at a point just outside of Earth's orbit around the sun. It has been collecting information on a billion stars, including their paths through space. The latest dataset was released just last year on 7.2 million stars. With data describing the paths of the four spacecraft and data describing the paths of a host of stars in hand, the researchers were able to work out when the paths of the four spacecraft might approach very far away star systems. The researchers found that the four spacecraft will come somewhat close to approximately 60 stars over the course of the next 1 million years—and will come within two parsecs of approximately 10 of them. They also found that Pioneer 10 will likely be the first to pass by a star system—one called HIP 117795. It sits in the constellation Cassiopeia. Their calculations show that the spacecraft will pass within 0.231 parsecs of the star in approximately 90,000 years. They also found that all four of the spacecraft will travel for a very long time before they collide with or are captured by a star system—on the order of 10 to the 20th power years. m.phys.org/news/2019-12-spacecraft-star.html?fbclid=IwAR2_ENSDMeRQe8xT80DlYMjHi-Ibd70bL85GEmFIdIzB4QgqARHfYEPv8-M |
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Post by swamprat on Mar 4, 2020 17:17:34 GMT
Voyager 2 is gathering science data again after recovering from a glitch in interstellar space
By Meghan Bartels an hour ago
(Image: © NASA/JPL-Caltech)
All five remaining instruments on NASA's venerable Voyager 2 spacecraft are back to gathering science data after power overuse in late January interrupted the probe's operations.
NASA made the announcement yesterday (March 3), over a month after the incident occurred. Troubleshooting for the spacecraft is a slow process because of its distance from Earth; it takes 17 hours for each command to reach the probe and for data indicating its efficacy to reach engineers.
"Voyager 2 has returned to normal operations following the anomaly on Jan. 25, 2020," NASA officials wrote in a statement. "The five operating science instruments, which were turned off by the spacecraft's fault protection routine, are back on and returning normal science data."
Voyager 2, like its twin Voyager 1, launched in August 1977 and has been exploring ever since. Such extensive space travel takes its toll; as the spacecraft have long exceeded their mission expectancy, engineers have needed to improvise ways to keep the probes going, particularly as their power supplies dwindle.
The January problem occurred when Voyager 2 missed a spin maneuver to calibrate its magnetic-field instrument. That glitch left two power-hungry systems on simultaneously; the spacecraft recognized the risk of the situation and triggered a preprogrammed fault-protection mode.
Since then, mission engineers have been working to turn off the power-sucking systems and to get Voyager 2's five remaining science instruments back to work. Those instruments are helping scientists understand what happens beyond the heliosphere, the bubble of space influenced by our sun. Voyager 2 left that bubble in November 2018, entering interstellar space.
www.space.com/voyager-2-gathering-data-after-glitch.html
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Post by SysConfig on Mar 4, 2020 17:31:47 GMT
Maybe if it powers off..it will start drifting the Sun will pull it back home..rethaw and heehaw back in business !  |
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Post by swamprat on Mar 5, 2020 21:05:45 GMT
When Voyager 2 Calls Home, Earth Soon Won’t Be Able to Answer
NASA will spend 11 months upgrading the only piece of its Deep Space Network that can send commands to the probe, which has crossed into interstellar space.
By Shannon Stirone
March 5, 2020
Voyager 2 has been traveling through space for 43 years, and is now 13 billion miles from Earth. But every so often, something goes wrong.
At the end of January, for instance, the robotic probe executed a routine somersault to beam scientific data back to Earth when an error triggered a shutdown of some of its functions.
“Everybody was extremely worried about recovering the spacecraft,” said Suzanne Dodd, who is the Voyager project manager at NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
The mission’s managers on our planet know what to do when such a fault occurs. Although it takes about a day and a half to talk to Voyager 2 at its current distance, they sent commands to restore its normal operations.
But starting on Monday for the next 11 months, they won’t be able to get word to the spry spacecraft in case something again goes wrong (although the probe can still stream data back to Earth). Upgrades and repairs are prompting NASA to take offline a key piece of space age equipment used to beam messages all around the solar system.
The downtime is necessary because of a flood of new missions to Mars scheduled to leave Earth this summer. But the temporary shutdown also highlights that the Deep Space Network, essential infrastructure relied upon by NASA and other space agencies, is aging and in need of expensive upgrades.
On any given day, NASA communicates with an armada of spacecraft in deep space. These long distance calls require the most powerful radio antennas in the world. Luckily NASA has its own switchboard, the Deep Space Network or DSN.
The DSN is one of space exploration’s most valuable assets. It comprises one station in the United States — in Goldstone, Calif. — and two overseas in Canberra, Australia and Madrid. It has been in operation nonstop for 57 years, and without it, spacecraft that traveled beyond the moon couldn’t communicate with Earth. It is used not only by NASA, but also the European Space Agency and the space programs of Japan, India and soon even the United Arab Emirates.
This summer, four missions are scheduled to launch to Mars. When the spacecrafts arrive at the red planet next year, three of them will need additional bandwidth to speak to Earth (China will use its own dishes for its Mars mission).
Each station on Earth is outfitted with three 34-meter antennas and one 70-meter antenna. They switch back and forth depending on where a spacecraft is in relation to our planet, and you can see which spacecraft are talking to Earth in real time by visiting NASA’s DSN Now website.
Because of Voyager 2’s trajectory relative to Earth, it can talk to only one station and one antenna in the network: Canberra’s 70 meter dish, also known as DSS 43. And that dish will need to be improved for the new Mars missions, prompting a shutdown and temporary dismantlement.
“Frankly, there’s never a good time to take down an asset and never a good time to fix the potholes in the road,” said Ms. Dodd, who is also director of the group that manages the Deep Space Network for NASA. “But you know you’re going to do the work at the airport, not during the Christmas rush. You’re going to do it when it’s less busy.”
Because Voyager 2 is considered a “geriatric” spacecraft, losing contact with it for any length of time is risky. And for the next 11 months, Earth’s ability to communicate with the probe, now in what’s considered interstellar space, will be limited.
“There is risk in this business as there is in anything in spaceflight,” said Glen Nagle, NASA’s outreach and administration lead for the station in Australia. “It’s a major change and the longest downtime for the dish in the eighteen years I’ve been here.”
One of the biggest risks is keeping Voyager 2’s communication antenna pointed at Earth. To do this, the probe fires its thrusters more than a dozen times a day to stay oriented. The mission’s managers have to trust that the automation on board will be executed relatively flawlessly for nearly a year.
Staying warm enough is another major concern. The Voyager team has been slowly shutting off instruments in order to use their heaters to keep the spacecraft’s fuel lines at a balmy 32 degrees Fahrenheit.
“We’ve done the analysis to show that we can get through the downtime,” with some margin for error, said Todd Barber, the propulsion engineer for the twin Voyager spacecraft. (Voyager 1 is able to communicate with other dishes.)
While the team won’t be able to command Voyager 2, they will still be listening to the spacecraft. By combining the power of the other antennas in Canberra, they will be able to collect its scientific observations.
“The Canberra site will still be getting data back from the spacecraft,” Ms. Dodd said. “The science data will still be coming down.”
Being able to only listen could prompt some anxiety. While Voyager 2 will keep collecting and sending back science data, should something go wrong, members of the team will be powerless to help it, and will just have to watch with their hands tied.
“We’ve been planning on this for over a year,” Ms. Dodd said. “I think like any good planning, we’re prepared for it. And we’ve done our best, you know, we’ve done the best that we can.”
And the operations to restore Voyager 2 during its recent troubles may highlight how much more life it could have in deepest space, Ms. Dodd said. Never before had all of the spacecraft’s instruments been shut off in this manner. Much to the mission managers’ delight and surprise, they were all brought back to life.
“They also came back on, which is actually pretty remarkable,” she said.
www.nytimes.com/2020/03/04/science/voyager-2-nasa-deep-space-network.html?utm_source=Nature+Briefing&utm_campaign=e44050dc5e-briefing-dy-20200305&utm_medium=email&utm_term=0_c9dfd39373-e44050dc5e-43274133
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