NASA's Voyager Spacecrafts

[selvaarchi]

looked for some old treads on Voyager but could not locate any

Reason for this post are August and September marks the 40th anniversary of the launches of Voyager 1 and 2 respectively. To mark it NASA has released a few articles.

https://www.jpl.nasa.gov/news/news.php?feature=6907

Humanity's farthest and longest-lived spacecraft, Voyager 1 and 2, achieve 40 years of operation and exploration this August and September. Despite their vast distance, they continue to communicate with NASA daily, still probing the final frontier.

Their story has not only impacted generations of current and future scientists and engineers, but also Earth's culture, including film, art and music. Each spacecraft carries a Golden Record of Earth sounds, pictures and messages. Since the spacecraft could last billions of years, these circular time capsules could one day be the only traces of human civilization.

"I believe that few missions can ever match the achievements of the Voyager spacecraft during their four decades of exploration," said Thomas Zurbuchen, associate administrator for NASA's Science Mission Directorate (SMD) at NASA Headquarters. "They have educated us to the unknown wonders of the universe and truly inspired humanity to continue to explore our solar system and beyond."

https://www.jpl.nasa.gov/news/news.php?feature=6908

Few missions can match the achievements of NASA's groundbreaking Voyager 1 and 2 spacecraft during their 40 years of exploration. Here's a short list of their major accomplishments to date.

https://www.jpl.nasa.gov/news/news.php?feature=6910

As NASA's twin Voyager spacecraft were changing our understanding of the solar system, they also spurred a leap in spacecraft communications.

The mission's impact is still visible in California's Mojave Desert. There, at NASA's Goldstone Deep Space Communications Complex, the arcs of antenna dishes peek out over craggy hilltops. Goldstone was the first place where the two Voyagers started to change the landscape. The farther they traveled, the bigger these dishes needed to be so they could send and receive radio waves necessary to track and communicate with the probes.

[Glom]

It's a spacecraft. It doesn't have treads. Or tyres for that matter.

[bknight]

I remember the vivid images of the Planets as they passed by. Most impressive.

[selvaarchi]

Emily Lakdawalla take on how the 40th anniversary of the spacecrafts on August 20th will be celebrated.

http://www.planetary.org/blogs/emily...f-voyager.html

Sunday, August 20 marks the 40th anniversary of the launch of Voyager 2. Tuesday, September 5, will be the 40th anniversary for Voyager 1. Round anniversaries like these have no special significance for spacecraft that have departed Earth's orbit; the significance is for those of us that the spaceships left behind on a planet that still revolves around the Sun once a year. Anniversaries are a good time to look back and consider our past. Throughout the next three weeks, we'll be posting new and classic material in honor of the Voyagers. Here's a preview of that material; I'll update this post with links as it's published.

[Noisy Rhysling]

Since the spacecraft could last billions of years, these circular time capsules could one day be the only traces of human civilization.

This would be true if we never launched anything else into interstellar space. Lyrical, but a bit silly.

[Sardonicone]

This would be true if we never launched anything else into interstellar space. Lyrical, but a bit silly.

New Horizons and I believe two of the Pioneer probes are also on Stellar escape trajectories.

[selvaarchi]

Now The Planetary Society is making available their back issues on the Voyager to mark the 40th anniversary.

http://www.planetary.org/blogs/emily...rsary-the.html

The Planetary Society came into being at the same time that the Voyagers began their grand tour of the outer solar system. Except for the Voyager missions, the 1980s were a grim period for planetary exploration. Consequently, the first decade of our member magazine, The Planetary Report, was dominated by Voyager coverage alongside reporting on the Russian missions to Mars and editorials about the future of planetary exploration.

Before the spread of the Internet, this magazine was how many space enthusiasts got any news about the Voyager missions beyond newspaper articles and television. As it still does today, The Planetary Report features the voices and perspectives of the scientists, engineers, and managers directly involved in the missions. In honor of the 40th anniversary of the Voyager missions, we're making publicly available seven back issues of The Planetary Report, featuring writing from Planetary Society founder Carl Sagan alongside numerous scientists and engineers from the Voyager mission: Ellis Miner, Torrance Johnson, William McLaughlin, David Morrison, Jeff Cuzzi, Bob Brown, Norman Ness, Carolyn Porco, Garry Hunt, David Stevenson, and more.

[selvaarchi]

Scientific American talks about a new documentary "The Farthest” about the Voyager flights.

https://www.scientificamerican.com/a...back-to-earth/

For many people who grew up in the 1970s and 1980s, the most emblematic space missions aren’t the pioneering flights of Yuri Gagarin, Alan Shepard or John Glenn. Or the audacious Apollo moon landings, or even the decades-spanning orbital journeys of space shuttles and Soyuz rockets to and from the International Space Station. Instead, the missions that have defined a generation’s conception of the space age are those of Voyager 1 and Voyager 2, twin spacecraft launched on a “Grand Tour” of the outer planets in the late summer of 1977. This week marks the 40th anniversary of the Voyager missions—and also the release of a new feature-length documentary, The Farthest: Voyager in Space, that celebrates their legacy.

[selvaarchi]

"NASA Voyager 2 Could Be Nearing Interstellar Space"

https://www.jpl.nasa.gov/news/news.php?feature=7252

NASA's Voyager 2 probe, currently on a journey toward interstellar space, has detected an increase in cosmic rays that originate outside our solar system. Launched in 1977, Voyager 2 is a little less than 11 billion miles (about 17.7 billion kilometers) from Earth, or more than 118 times the distance from Earth to the Sun.

Since 2007 the probe has been traveling through the outermost layer of the heliosphere -- the vast bubble around the Sun and the planets dominated by solar material and magnetic fields. Voyager scientists have been watching for the spacecraft to reach the outer boundary of the heliosphere, known as the heliopause. Once Voyager 2 exits the heliosphere, it will become the second human-made object, after Voyager 1, to enter interstellar space.

[schlaugh]

Looks like Voyager 2 has crossed the interstellar boundary.

https://mobile.twitter.com/NASAVoyager

Grand Tour Encore: Voyager 2, the only spacecraft to have visited Jupiter, Saturn, Uranus and Neptune, has left the Sun's bubble and joined me in interstellar space!

ETA: annnd...looks like I copied the wrong tweet. The one above is “from” Voyager 1. But you get the drift.

Sent from my iPhone using Tapatalk Pro

[selvaarchi]

Looks like Voyager 2 has crossed the interstellar boundary.

https://mobile.twitter.com/NASAVoyager



ETA: annnd...looks like I copied the wrong tweet. The one above is “from” Voyager 1. But you get the drift.

Emily Lakdawalla on the event. She also highlights that, Voyager 2 still has a working Plasma Spectrometer (PLS).

http://www.planetary.org/blogs/emily...eliopause.html

At a press briefing at the American Geophysical Union meeting today, NASA announced that several instruments on Voyager 2 confirmed that it had passed beyond the solar system boundary known as the heliopause. Unlike Voyager 1, which spent several years flirting with this boundary, the signs were pretty clear on Voyager 2. It helps that Voyager 2’s Plasma Spectrometer (PLS) is functioning (Voyager 1’s failed in 1980). Voyager 2 passed the termination shock in 2007; its passage across the heliopause means that it is now sensing the interstellar medium and is beyond the reach of the solar wind. It is still well inside the solar system: the Voyagers will take a few hundred years to reach the Oort cloud, the birthplace of comets. I like Phil Metzger’s framing of this news: Voyager 2 “went outside the Sun.”

More from Space Daily.

http://www.spacedaily.com/reports/NA...Space_999.html

For the second time in history, a human-made object has reached the space between the stars. NASA's Voyager 2 probe now has exited the heliosphere - the protective bubble of particles and magnetic fields created by the Sun.

Comparing data from different instruments aboard the trailblazing spacecraft, mission scientists determined the probe crossed the outer edge of the heliosphere on Nov. 5. This boundary, called the heliopause, is where the tenuous, hot solar wind meets the cold, dense interstellar medium. Its twin, Voyager 1, crossed this boundary in 2012, but Voyager 2 carries a working instrument that will provide first-of-its-kind observations of the nature of this gateway into interstellar space.

[pumpkinpie]

Emily Lakdawalla on the event. She also highlights that, Voyager 2 still has a working Plasma Spectrometer (PLS).

http://www.planetary.org/blogs/emily...eliopause.html
At a press briefing at the American Geophysical Union meeting today, NASA announced that several instruments on Voyager 2 confirmed that it had passed beyond the solar system boundary known as the heliopause. Unlike Voyager 1, which spent several years flirting with this boundary, the signs were pretty clear on Voyager 2. It helps that Voyager 2’s Plasma Spectrometer (PLS) is functioning (Voyager 1’s failed in 1980). Voyager 2 passed the termination shock in 2007; its passage across the heliopause means that it is now sensing the interstellar medium and is beyond the reach of the solar wind. It is still well inside the solar system: the Voyagers will take a few hundred years to reach the Oort cloud, the birthplace of comets. I like Phil Metzger’s framing of this news: Voyager 2 “went outside the Sun.”



More from Space Daily.

http://www.spacedaily.com/reports/NA...Space_999.html

Yes, yes, yes. Finally someone has validated what I have been seeing as a misinterpretation of "interstellar medium." The comets in the Oort cloud orbit the Sun, so if the Voyagers have left the solar system, as many articles report, that implies the comets are not a part of it. I teach about the solar system using a 3D visualization software where you can fly from Earth, through the Oort cloud, and beyond, at accurate distance scales. It even has the trajectories of the Voyager spacecraft, so you can see how much farther away the Oort cloud is, yet the objects are still bound to the Sun by gravity.

It really comes down to definitions and semantics. The interstellar medium is outside the Sun's heliopause, and that is determined by one of the Sun's influences. The solar system is, according to Merriam-Webster, "the sun together with the group of celestial bodies that are held by its attraction and revolve around it." As an educator, it's important for me to know these differences and be able to explain them, because if I say one thing and the media says another, there is a good chance some space aficionado in the audience will call me on it!

Now, this doesn't solve the problem of having to describe the difference between "interstellar medium" and "solar system." But I'm happy to do so and not seem like I'm contradicting these reports.

[Swift]

As they say, pumpkinpie, it makes for a "teachable moment".

[selvaarchi]

"Voyager Wide-Angle Views of Jupiter"

http://www.planetary.org/blogs/guest...s-jupiter.html

Last month marked the 40th anniversary of the historic Voyager 1 encounter with Jupiter in 1979. Voyager 1 was not the first robotic visitor to Jupiter; Pioneers 10 and 11 flew past the gas giant in 1973 and 1974. But while the Pioneers’ primitive spin-scan photopolarimeters took very good, groundbreaking images of the planet, they couldn’t compete with the TV cameras of the Voyagers.

The cameras, while not at the forefront of technology in the late-1970s, were still a reliable and proven method of capturing images in deep space. They had a pedigree stretching back to the early Mariner probes—not surprising, given that the Voyager program was essentially a continuation of Mariner (the two Voyager probes were developed under the moniker ‘Mariner-Jupiter-Saturn’).

Each Voyager carried a pair of TV cameras, mounted behind telescopes of differing focal length, giving the operators the option of taking images spanning 0.4 degrees (the NAC or narrow-angle camera), or 3 degrees (the WAC or wide-angle camera). In traditional photographic terms, both systems are squarely in the telephoto category.

Most of the valuable photographic data came from the NAC, given the greater resolution it offered. However, the overlooked WAC had two principal roles: to provide context views of the highly localized NAC shots, while also providing continuous photographic surveillance of global-scale features on Jupiter and its moons near the period around closest approach.

[selvaarchi]

"Keeping NASA's Oldest Explorers Going"

http://www.spacedaily.com/reports/Ke...Going_999.html

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.

[Swift]

Interesting article. The excerpt sounded like bad news (they weren't going to operate the CRS), but upon reading the full article, I think it is actually good news: the CRS can operate without the heater.

[selvaarchi]

"NASA Has Found a Weird, Unexplained Boundary in Interstellar Space"

https://www.vice.com/en_in/article/d...rstellar-space

For instance, Voyager 2 discovered a previously unknown border just outside the heliopause, reports a team led by Edward Stone, a professor of physics at Caltech and project scientist on the Voyager program since its inception in the 1970s.

The researchers call this threshold a “cosmic ray boundary layer” because it signals where the probe experienced a shift in the gradient of cosmic rays from the great beyond and the lower-energy particles typical of the familiar environment around our Sun.

There’s evidence that Voyager 1 also encountered one of these cosmic ray boundary layers, but interestingly, it was located on the inside of the heliopause.

“There appear to be cosmic ray boundary layers on both sides of the heliopause, with the outer one only being evident at the position of Voyager 2,” Stone’s team said in the study. “This cosmic ray boundary layer on the outside of the heliopause was not evident at the place and time where Voyager 1 crossed it.”

[Roger E. Moore]

Voyager 2 articles on its interstellar space experience.

https://arxiv.org/abs/1912.02476

Voyager 2 enters interstellar space
R. Du Toit Strauss
(Submitted on 5 Dec 2019)

After 41 years of travel, the Voyager 2 spacecraft joins its twin in interstellar space. A suite of papers report Voyager 2's experience of its transition through the heliosheath and heliopause to what lies beyond.

[Roger E. Moore]

And where are our interstellar probes going, anyway?

https://arxiv.org/abs/1912.03503

Future stellar flybys of the Voyager and Pioneer spacecraft
Coryn A.L. Bailer-Jones (MPIA Heidelberg), Davide Farnocchia (JPL Pasadena)
(Submitted on 7 Dec 2019)

The Pioneer 10 and 11 and Voyager 1 and 2 spacecraft, launched in the 1970s, are heading out of the solar system. Using the astrometric and radial velocity data from the second Gaia data release, we integrate the trajectories of 7.4 million stars, and the spacecraft, through a Galactic potential in order to identify those stars the spacecraft will pass closest to. The closest encounters for all spacecraft take place at separations between 0.2 and 0.5 pc within the next million years. The closest encounter will be by Pioneer 10 with the K8 dwarf HIP 117795, at 0.23 pc in 90 kyr at a high relative velocity of 291 km/s.

[Glom]

I don't think the spacecraft will be able to send back useful data during those flybys. They're RTG powered and they lose power output over time.

[CJSF]

I don't think the spacecraft will be able to send back useful data during those flybys. They're RTG powered and they lose power output over time.

Yes. Both are expected to run out of sufficient power for any instrumentation or communication in the next 5-10 years.

CJSF

[selvaarchi]

"Revisiting Decades-Old Voyager 2 Data, Scientists Find One More Secret"

https://www.jpl.nasa.gov/news/news.php?feature=7623

Eight and a half years into its grand tour of the solar system, NASA's Voyager 2 spacecraft was ready for another encounter. It was Jan. 24, 1986, and soon it would meet the mysterious seventh planet, icy-cold Uranus.

Over the next few hours, Voyager 2 flew within 50,600 miles (81,433 kilometers) of Uranus' cloud tops, collecting data that revealed two new rings, 11 new moons and temperatures below minus 353 degrees Fahrenheit (minus 214 degrees Celsius). The dataset is still the only up-close measurements we have ever made of the planet.

Three decades later, scientists reinspecting that data found one more secret.

Unbeknownst to the entire space physics community, 34 years ago Voyager 2 flew through a plasmoid, a giant magnetic bubble that may have been whisking Uranus' atmosphere out to space. The finding, reported in Geophysical Research Letters, raises new questions about the planet's one-of-a-kind magnetic environment.

[selvaarchi]

"NASA Contacts Voyager 2 Using Upgraded Deep Space Network Dish"

https://www.jpl.nasa.gov/news/news.php?feature=7775

On Oct. 29, mission operators sent a series of commands to NASA's Voyager 2 spacecraft for the first time since mid-March. The spacecraft has been flying solo while the 70-meter-wide (230-foot-wide) radio antenna used to talk to it has been offline for repairs and upgrades. Voyager 2 returned a signal confirming it had received the "call" and executed the commands without issue.

The call to Voyager 2 was a test of new hardware recently installed on Deep Space Station 43, the only dish in the world that can send commands to Voyager 2. Located in Canberra, Australia, it is part of NASA's Deep Space Network (DSN), a collection of radio antennas around the world used primarily to communicate with spacecraft operating beyond the Moon. Since the dish went offline, mission operators have been able to receive health updates and science data from Voyager 2, but they haven't been able to send commands to the far-flung probe, which has traveled billions of miles from Earth since its 1977 launch.

[Selenite]

"NASA Contacts Voyager 2 Using Upgraded Deep Space Network Dish"

https://www.jpl.nasa.gov/news/news.php?feature=7775

Not sure why, but I must admit I find it heartening that we still have a tenuous contact with these probes after 43 years.

[publiusr]

TAU type missions will go even farther afield. I hope for Project Lyra.

[Swift]

Not sure why, but I must admit I find it heartening that we still have a tenuous contact with these probes after 43 years.

Yes, very much so

[Van Rijn]

Not sure why, but I must admit I find it heartening that we still have a tenuous contact with these probes after 43 years.

The Voyagers are my favorite robot spacecraft, what with the number of worlds visited, the interstellar mission and their longevity. It’s amazing so much was done with 1970s technology.

[Selenite]

The Voyagers are my favorite robot spacecraft, what with the number of worlds visited, the interstellar mission and their longevity. It’s amazing so much was done with 1970s technology.

Yes they are remarkable machines. One of them even managed to work in an album cover flyby in the 1980s.