from the get-out-of-my-solar-system dept.
NASA's historic Voyager mission has now been exploring the heavens for four decades.
The Voyager 2 spacecraft launched on Aug. 20, 1977, a few weeks before its twin, Voyager 1. Together, the two probes conducted an unprecedented "Grand Tour" of the outer solar system, beaming home up-close looks at Jupiter, Saturn, Uranus, Neptune and many of the moons of these giant planets.
This work revealed a jaw-dropping diversity of worlds, fundamentally reshaping scientists' understanding of the solar system. And then the Voyagers kept on flying. In August 2012, Voyager 1 became the first spacecraft ever to reach interstellar space — and Voyager 2 is expected to arrive in this exotic realm soon as well.
The rest of the article is a Q&A with Voyager project scientist and former director of the NASA Jet Propulsion Laboratory Ed Stone.
No missions have been sent to Uranus or Neptune since Voyager 2 visited them in 1986 and 1989.
The Ice Giants Pre-Decadal Study group has proposed sending a mission to either Uranus or Neptune. Only one mission is likely to be approved due to a shortage of plutonium-238 for the radioisotope thermoelectric generators required for an outer solar system mission:
Uranus and Neptune have never got much attention from us – we've only passed each once and never hung around. But that could change. A NASA group has now outlined possible missions to make it to one of these outer worlds to gather data on their composition. This should teach us about them and similar planets in other solar systems.
"The preferred mission is an orbiter with an atmospheric probe to either Uranus or Neptune – this provides the highest science value, and allows in depth study of all aspects of either planet's system: rings, satellites, atmosphere, magnetosphere," says Amy Simon, co-chair of the Ice Giants Pre-Decadal Study group.
There are four proposed missions – three orbiters and a fly-by of Uranus, which would include a narrow angle camera to draw out details, especially of the ice giant's moons. It would also drop an atmospheric probe to take a dive into Uranus's atmosphere to measure the levels of gas and heavy elements there.
The three must-haves for each orbiter mission are a narrow-angle camera, a doppler imager and a magnetometer, while an orbiter containing 15 instruments would add plasma detectors, infrared and UV imaging, dust detection and microwave radar capability. The orbiter could be either a Neptune mission with an atmospheric probe, a Uranus probe of the same design, or a craft sent to a[sic] Uranus that ditches the atmospheric probe for the suite of 15 instruments.
Obligatory grade school humor:
Also at The Verge.
Forty years ago, we sent a map to Earth sailing deep into the cosmos. Copies of this map are etched into each of the twin Voyager spacecraft, which launched in the late 1970s and are now the farthest spacecraft from home. One of the probes has already slipped into interstellar space, and the other is skirting the fringes of our sun's immediate neighborhood. If it's ever intercepted and decoded by extraterrestrials, the map will not only reveal where to find our watery little world, but also when the space probe that delivered it to alien hands left home.
[...] "Back when Drake did the pulsar map, and Carl Sagan and the whole team did the Voyager record, there hadn't been very much debate over the pros and cons of contact with extraterrestrial intelligence," says York University's Kathryn Denning, an anthropologist who studies the ethics of sending messages to extraterrestrials. "Now, however, as you know, there is a major debate among scientists and a variety of stakeholders about the wisdom of doing anything other than listening."
[...] "In those days, all the people I dealt with were optimists, and they thought the ETs would be friendly," Drake says. "Nobody thought, even for a few seconds, about whether this might be a dangerous thing to do." So what are the chances of the map actually reaching extraterrestrial shores aboard the Voyagers? "Very small," Drake says. "The thing is going something like 10 kilometers per second, at which speed it takes—for the typical separation of stars—about half a million years to go from one star to another. And of course, it's not aimed at any star, it's just going where it's going."
Of course, aliens could just use gigantic space telescopes to find Earth and other watery planets instead of accidentally intercepting a tiny spacecraft. And humanity will either be super-advanced, post-apocalyptic, or just gone by the time aliens can find a map and head for Earth (even if they have faster-than-light travel, the spacecraft won't be relatively far away from Earth anytime soon).
Despite the recent whinging about whether or not the maps on the Pioneer and Voyager space probes might have been a big mistake that might lead to Earth being invaded by hostile aliens, it turns out that the pulsar maps included on these probes are actually worthless for determining the location of our Solar System. Pulsars were first discovered in 1967 by Jocelyn Bell-Burnell, and at the time they were believed to be unique and stable landmarks suitable for that purpose. However, subsequent discoveries have shown that they are not actually as stable and reliable as they were first believed. Ethan Siegel at Starts With A Bang has an article on this:
[...] While fear-mongers foolishly claim that hostile aliens could follow the Voyager maps back to Earth, the maps themselves are actually among the most useless information aboard Voyager. According to Frank Drake, who worked on the Voyager message with Carl Sagan:
"We needed to put something on the Voyager that said where it came from, and how long it was traveling... There was a magic about pulsars ... no other things in the sky had such labels on them. Each one had its own distinct pulsing frequency, so it could be identified by anybody, including other creatures after a long period of time and far, far away."
Although these identifiers were thought to be unique and stable, we now know that long-term changes will render this map useless. If you tried to identify Earth by the presence of Pangaea, you'd be sorely disappointed. By sending the messages we did with Voyager, we actually delivered a much more challenging problem to any aliens "lucky" enough to come upon it. The idea to send pulsar positions and frequencies was a brilliant one, but by the time anyone receives it, they'll only encounter one of the most difficult-to-decipher riddles we could have possibly imposed.
In summary, it turns out that pulsars are far from being as unique, rare, and stable as they were believed to be in the 1970s when they came up with the idea. There are an estimated one billion neutron stars in the Milky Way, and almost all of these will look like pulsars somewhere in space because their spin and magnetic axes aren't perfectly aligned and so they will beam radio waves in some direction. The pulsar periods are also not as unique as they were at the time believed, so any extraterrestrial finding the Voyager plaque will have a hard time figuring out which fourteen pulsars out of a billion are described. Second, the properties of a pulsar can change in unpredictable fashion. Pulsars have since been observed to appear and disappear as the orientations of their spins relative to Earth change due to various factors, such as their motion in space and events internal to the pulsar itself such as starquakes and pulsar speedup. If one really wanted to tell aliens were we were it would have been better to give them a description of the Solar System, with the astronomical properties and description of our sun and the planets. It is, after all, how we identify exoplanet systems today.
Voyager 1 is still alive out there, barreling into the cosmos more than 15 billion miles away. However, a computer problem has kept the mission's loyal support team in Southern California from knowing much more about the status of one of NASA's longest-lived spacecraft.
The computer glitch cropped up on November 14, and it affected Voyager 1's ability to send back telemetry data, such as measurements from the spacecraft's science instruments or basic engineering information about how the probe was doing. [...] "It would be the biggest miracle if we get it back. We certainly haven't given up," said Suzanne Dodd, Voyager project manager at NASA's Jet Propulsion Laboratory, in an interview with Ars. "There are other things we can try. But this is, by far, the most serious since I've been project manager."
Dodd became the project manager for NASA's Voyager mission in 2010, overseeing a small cadre of engineers responsible for humanity's exploration into interstellar space. Voyager 1 is the most distant spacecraft ever, speeding away from the Sun at 38,000 mph (17 kilometers per second). [...] The latest problem with Voyager 1 lies in the probe's Flight Data Subsystem (FDS), one of three computers on the spacecraft working alongside a command-and-control central computer and another device overseeing attitude control and pointing. [...] In November, the data packages transmitted by Voyager 1 manifested a repeating pattern of ones and zeros as if it were stuck, according to NASA. Dodd said engineers at JPL have spent the better part of three months trying to diagnose the cause of the problem. She said the engineering team is "99.9 percent sure" the problem originated in the FDS, which appears to be having trouble "frame syncing" data. [...] "It's likely somewhere in the FDS memory," Dodd said. "A bit got flipped or corrupted. But without the telemetry, we can't see where that FDS memory corruption is."
[...] "We have sheets and sheets of schematics that are paper, that are all yellowed on the corners, and all signed in 1974," Dodd said. "They're pinned up on the walls and people are looking at them. That's a whole story in itself, just how to get to the information you need to be able to talk about the commanding decisions or what the problem might be." [...] "It is difficult to command Voyager," Dodd said. "We don't have any type of simulator for this. We don't have any hardware simulator. We don't have any software simulator... There's no simulator with the FDS, no hardware where we can try it on the ground first before we send it. So that makes people more cautious, and it's a balance between getting commanding right and taking risks."
[...] The spacecraft's vast distance and position in the southern sky require NASA to use the largest 230-foot (70-meter) antenna at a Deep Space Network tracking site in Australia, one of the network's most in-demand antennas.
"The data rates are very low, and this anomaly causes us not to have any telemetry," Dodd said. "We're kind of shooting in the blind a little bit because we don't know what the status of the spacecraft is completely."
Previously on SoylentNews:
Engineers Work to Fix Voyager 1 Computer - 20231215