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Nasa spacecraft embarks on historic journey into interstellar space.

NASA’s Voyager 1 spacecraft officially is the first human-made object to venture into interstellar space. The 36-year-old probe is about 12 billion miles (19 billion kilometers) from our sun.

New and unexpected data indicate Voyager 1 has been traveling for about one year through plasma, or ionized gas, present in the space between stars. Voyager is in a transitional region immediately outside the solar bubble, where some effects from our sun are still evident. A report on the analysis of this new data, an effort led by Don Gurnett and the plasma wave science team at the University of Iowa, Iowa City, is published in Thursday’s edition of the journal Science.

“Now that we have new, key data, we believe this is mankind’s historic leap into interstellar space,” said Ed Stone, Voyager project scientist based at the California Institute of Technology, Pasadena. “The Voyager team needed time to analyze those observations and make sense of them. But we can now answer the question we’ve all been asking — ‘Are we there yet?’ Yes, we are.”

Voyager 1 first detected the increased pressure of interstellar space on the heliosphere, the bubble of charged particles surrounding the sun that reaches far beyond the outer planets, in 2004. Scientists then ramped up their search for evidence of the spacecraft’s interstellar arrival, knowing the data analysis and interpretation could take months or years.

Voyager 1 does not have a working plasma sensor, so scientists needed a different way to measure the spacecraft’s plasma environment to make a definitive determination of its location. A coronal mass ejection, or a massive burst of solar wind and magnetic fields, that erupted from the sun in March 2012 provided scientists the data they needed. When this unexpected gift from the sun eventually arrived at Voyager 1’s location 13 months later, in April 2013, the plasma around the spacecraft began to vibrate like a violin string. On April 9, Voyager 1’s plasma wave instrument detected the movement. The pitch of the oscillations helped scientists determine the density of the plasma. The particular oscillations meant the spacecraft was bathed in plasma more than 40 times denser than what they had encountered in the outer layer of the heliosphere. Density of this sort is to be expected in interstellar space.

The plasma wave science team reviewed its data and found an earlier, fainter set of oscillations in October and November 2012. Through extrapolation of measured plasma densities from both events, the team determined Voyager 1 first entered interstellar space in August 2012.

“We literally jumped out of our seats when we saw these oscillations in our data — they showed us the spacecraft was in an entirely new region, comparable to what was expected in interstellar space, and totally different than in the solar bubble,” Gurnett said. “Clearly we had passed through the heliopause, which is the long-hypothesized boundary between the solar plasma and the interstellar plasma.”

The new plasma data suggested a timeframe consistent with abrupt, durable changes in the density of energetic particles that were first detected on Aug. 25, 2012. The Voyager team generally accepts this date as the date of interstellar arrival. The charged particle and plasma changes were what would have been expected during a crossing of the heliopause.

“The team’s hard work to build durable spacecraft and carefully manage the Voyager spacecraft’s limited resources paid off in another first for NASA and humanity,” said Suzanne Dodd, Voyager project manager, based at NASA’s Jet Propulsion Laboratory (JPL), Pasadena, Calif. “We expect the fields and particles science instruments on Voyager will continue to send back data through at least 2020. We can’t wait to see what the Voyager instruments show us next about deep space.”

Voyager 1 and its twin, Voyager 2, were launched 16 days apart in 1977. Both spacecraft flew by Jupiter and Saturn. Voyager 2 also flew by Uranus and Neptune. Voyager 2, launched before Voyager 1, is the longest continuously operated spacecraft. It is about 9.5 billion miles (15 billion kilometers) away from our sun.

Voyager mission controllers still talk to or receive data from Voyager 1 and Voyager 2 every day, though the emitted signals are currently very dim, at about 23 watts — the power of a refrigerator light bulb. By the time the signals get to Earth, they are a fraction of a billion-billionth of a watt. Data from Voyager 1’s instruments are transmitted to Earth typically at 160 bits per second, and captured by 34- and 70-meter NASA Deep Space Network (DSN) stations. Traveling at the speed of light, a signal from Voyager 1 takes about 17 hours to travel to Earth. After the data are transmitted to JPL and processed by the science teams, Voyager data are made publicly available.

“Voyager has boldly gone where no probe has gone before, marking one of the most significant technological achievements in the annals of the history of science, and adding a new chapter in human scientific dreams and endeavors,” said John Grunsfeld, NASA’s associate administrator for science in Washington. “Perhaps some future deep space explorers will catch up with Voyager, our first interstellar envoy, and reflect on how this intrepid spacecraft helped enable their journey.”

Scientists do not know when Voyager 1 will reach the undisturbed part of interstellar space where there is no influence from our sun. They also are not certain when Voyager 2 is expected to cross into interstellar space, but they believe it is not very far behind.

JPL built and operates the twin Voyager spacecraft. The Voyagers Interstellar Mission is a part of NASA’s Heliophysics System Observatory, sponsored by the Heliophysics Division of NASA’s Science Mission Directorate in Washington. NASA’s DSN, managed by JPL, is an international network of antennas that supports interplanetary spacecraft missions and radio and radar astronomy observations for the exploration of the solar system and the universe. The network also supports selected Earth-orbiting missions.

The cost of the Voyager 1 and Voyager 2 missions — including launch, mission operations and the spacecraft’s nuclear batteries, which were provided by the Department of Energy — is about $988 million through September.

For a sound file of the oscillations detected by Voyager in interstellar space, animations and other information, visit:

For an image of the radio signal from Voyager 1 on Feb. 21 by the National Radio Astronomy Observatory’s Very Long Baseline Array, which links telescopes from Hawaii to St. Croix, visit:

Protected: Milky Way’s Black Hole Was “Birth Cry” of Radio Astronomy

Dwayne Brown Headquarters, Washington 202-358-1726 [email protected] Jia-Rui C. Cook Jet Propulsion Laboratory, Pasadena, Calif. 818-354-0850 [email protected]

Voyager 1: 'The Spacecraft That Could' Hits New Milestone

Voyager 1, already the most distant human-made object in the cosmos, reaches 100 astronomical units from the sun on Tuesday, August 15 at 5:13 p.m. Eastern time (2:13 p.m. Pacific time).

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Stephen Clark, Ars Technica

How NASA Repaired Voyager 1 From 15 Billion Miles Away

Engineers have partially restored a 1970s-era computer on NASA's Voyager 1 spacecraft after five months of long-distance troubleshooting , building confidence that humanity's first interstellar probe can eventually resume normal operations.

Several dozen scientists and engineers gathered Saturday in a conference room at NASA's Jet Propulsion Laboratory, or connected virtually, to wait for a new signal from Voyager 1. The ground team sent a command up to Voyager 1 on Thursday to recode part of the memory of the spacecraft's Flight Data Subsystem (FDS) , one of the probe's three computers.

“In the minutes leading up to when we were going to see a signal, you could have heard a pin drop in the room,” said Linda Spilker, project scientist for NASA's two Voyager spacecraft at JPL. “It was quiet. People were looking very serious. They were looking at their computer screens. Each of the subsystem (engineers) had pages up that they were looking at, to watch as they would be populated.”

Finally, a Breakthrough

Launched nearly 47 years ago, Voyager 1 is flying on an outbound trajectory more than 15 billion miles (24 billion kilometers) from Earth, and it takes 22.5 hours for a radio signal to cover that distance at the speed of light. This means it takes nearly two days for engineers to uplink a command to Voyager 1 and get a response.

In November, Voyager 1 suddenly stopped transmitting its usual stream of data containing information about the spacecraft's health and measurements from its scientific instruments. Instead, the spacecraft's datastream was entirely unintelligible. Because the telemetry was unreadable, experts on the ground could not easily tell what went wrong. They hypothesized the source of the problem might be in the memory bank of the FDS.

There was a breakthrough last month when engineers sent up a novel command to “poke” Voyager 1's FDS to send back a readout of its memory. This readout allowed engineers to pinpoint the location of the problem in the FDS memory . The FDS is responsible for packaging engineering and scientific data for transmission to Earth.

After a few weeks, NASA was ready to uplink a solution to get the FDS to resume packing engineering data. This datastream includes information on the status of the spacecraft—things like power levels and temperature measurements. This command went up to Voyager 1 through one of NASA's large Deep Space Network antennae on Thursday.

Then, the wait for a response. Spilker, who started working on Voyager right out of college in 1977, was in the room when Voyager 1's signal reached Earth on Saturday.

“When the time came to get the signal, we could clearly see all of a sudden, boom, we had data, and there were tears and smiles and high fives,” she told Ars. “Everyone was very happy and very excited to see that, hey, we're back in communication again with Voyager 1. We're going to see the status of the spacecraft, the health of the spacecraft, for the first time in five months.”

Scott Gilbertson

Christopher Null

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Throughout the five months of troubleshooting, Voyager's ground team continued to receive signals indicating the spacecraft was still alive. But until Saturday, they lacked insight into specific details about the status of Voyager 1.

“It’s pretty much just the way we left it,” Spilker said. “We're still in the initial phases of analyzing all of the channels and looking at their trends. Some of the temperatures went down a little bit with this period of time that's gone on, but we're pretty much seeing everything we had hoped for. And that's always good news.”

Relocating Code

Through their investigation, Voyager's ground team discovered that a single chip responsible for storing a portion of the FDS memory had stopped working, probably due to either a cosmic ray hit or a failure of aging hardware. This affected some of the computer's software code.

“That took out a section of memory,” Spilker said. “What they have to do is relocate that code into a different portion of the memory, and then make sure that anything that uses those codes, those subroutines, know to go to the new location of memory, for access and to run it.”

Only about 3 percent of the FDS memory was corrupted by the bad chip, so engineers needed to transplant that code into another part of the memory bank. But no single location is large enough to hold the section of code in its entirety, NASA said.

So the Voyager team divided the code into sections for storage in different places in the FDS. This wasn't just a copy-and-paste job. Engineers needed to modify some of the code to make sure it will all work together. “Any references to the location of that code in other parts of the FDS memory needed to be updated as well,” NASA said in a statement.

Newer NASA missions have hardware and software simulators on the ground, where engineers can test new procedures to make sure they do no harm when they uplink commands to the real spacecraft. Due to its age, Voyager doesn't have any ground simulators, and much of the mission's original design documentation remains in paper form and hasn't been digitized.

“It was really eyes-only to look at the code,” Spilker said. “So we had to triple check. Everybody was looking through and making sure we had all of the links coming together.”

This was just the first step in restoring Voyager 1 to full functionality. “We were pretty sure it would work, but until it actually happened, we didn't know 100 percent for sure,” Spilker said.

“The reason we didn’t do everything in one step is that there was a very limited amount of memory we could find quickly, so we prioritized one data mode (the engineering data mode), and relocated only the code to restore that mode,” said Jeff Mellstrom, a JPL engineer who leads the Voyager 1 “tiger team” tasked with overcoming this problem.

“The next step, to relocate the remaining three actively used science data modes, is essentially the same,” Mellstrom said in a written response to Ars. “The main difference is the available memory constraint is now even tighter. We have ideas where we could relocate the code, but we haven’t yet fully assessed the options or made a decision. These are the first steps we will start this week.”

It could take “a few weeks” to go through the sections of code responsible for packaging Voyager 1's science data in the FDS, Spilker said.

That will be the key payoff, Spilker said. Voyager 1 and its twin spacecraft, Voyager 2, are the only operating probes flying in the interstellar medium, the diffuse gas between the stars. Their prime missions are long over. Voyager 1 flew by Jupiter and Saturn in 1979 and 1980, then got a gravitational boost toward the outer edge of the Solar System. Voyager 2 took a slower trajectory and encountered Jupiter, Saturn, Uranus, and Neptune.

For the past couple of decades, NASA has devoted Voyager's instruments to studying cosmic rays, the magnetic field, and the plasma environment in interstellar space. They're not taking pictures anymore. Both probes have traveled beyond the heliopause, where the flow of particles emanating from the Sun runs into the interstellar medium.

But any scientific data collected by Voyager 1 since November 14 has been lost. The spacecraft does not have the ability to store science data onboard. Voyager 2 has remained operational during the outage of Voyager 1.

Scientists are eager to get their hands on Voyager 1's science data again. “With the results we got on Saturday, we have new confidence that we can put together the pieces we need to now get back the science data,” Spilker said.

“One thing I'm particularly excited about—there's this feature in the Voyager 1 data. We nicknamed it Pressure Front 2,” Spilker said. “Pressure Front 2 is a jump in both the density of the plasma around the spacecraft and the magnetic field. It's lasted for three-and-a-half years.”

“We'd like to see, is this still there?” she continued. “It's different from what we've seen in the past, and we're trying to figure out, is it some influence coming from the Sun, or is it actually something coming from interstellar space that's creating this feature? So we'd like to see it again, get more data, and be able to study it more carefully.”

This story originally appeared on Ars Technica .

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The July issue of Scientific American magazine has a terrific review of the Voyager space mission that details the trips Voyagers 1 and 2 have made through the Solar System. The article is titled “ Record-Breaking Voyager Spacecraft Begin to Power Down .” Both spacecraft have now entered interstellar space and are the first human artifacts to do so. Tim Folger wrote the article for Scientific American . Towards the end of the article, Folger points out that Voyagers 1 and 2 were designed before the advent of the microprocessor and that the mission has lasted 44 years, so far, which is about 40 years longer than the planned design life for the spacecraft.

The article then quotes Stamatios Krimigis, a PhD physicist and space scientist who’s spent more than half a century at the Johns Hopkins Applied Physics Laboratory. Krimigis says, “The amount of software on these instruments is slim to none. On the whole, I think the mission lasted so long because almost everything was hardwired. Today’s engineers don’t know how to do this. I don’t know if it’s even possible to build such a simple spacecraft [now]. Voyager is the last of its kind.”

Now hold on there.

I mean no disrespect to Dr. Krimigis, but he’s somewhat myopic about hardwired circuits. Many of today’s engineers know how to design hardwired logic circuits; we just don’t use TTL or CMOS chips any longer, because that’s an inefficient and outmoded way to design circuits at the board level. Instead, hardware engineers design systems based on FPGAs. We no longer rely solely on schematics for our hardware designs; VHDL and Verilog allow us to develop far more complex logic circuits.

Hardware design for space applications is alive and well and closely tracks the rest of hardware design, and it has migrated to FPGAs. Engineers designing for high-radiation environments in space have developed several radiation-tolerant design techniques for FPGAs including safe FSMs (finite state machines), Hamming-coded FSMs, and Triple Module Redundancy (TMR). Major FPGA vendors including AMD/Xilinx, Lattice, and Microchip (formerly Microsemi and Actel) either have sent devices into space as essential components on various missions or they offer radiation-tolerant FPGAs for space applications, or both.

For example, various Microchip and AMD/Xilinx FPGAs were aboard the twin Spirit and Opportunity Mars rovers and are on the plutonium-powered Perseverance rover currently trundling around on Mars. Also, a Microchip ProASIC3 FPGA buzzed around the thin Martian atmosphere aboard the enormously successful Ingenuity helicopter, serving as an interface to the helicopter’s sensors and servo actuators. (See “ An FPGA Flies on Mars .”) Another Microchip FPGA took the express bus to Pluto aboard NASA’s New Horizon’s mission as part of an instrument package designed to measure Pluto’s atmospheric temperature and pressure profiles. These are just a few examples. There are many.

In addition to FPGAs that have flown in space, there are FPGAs that aspire to fly in space. CAES (Cobham Advanced Electronic Solutions) signed an agreement early this year with Lattice Semiconductor and now offers versions of the Certus-Pro NX FPGAs, which are manufactured with a 28nm FDSOI process that’s inherently radiation-tolerant.

Voyager 1 and 2 launched in 1977. That was several years before FPGA’s were invented, so there are no FPGAs on these spacecraft. In addition, the circuit design of the Voyager spacecraft did not rely exclusively on hardwired electronics as you might infer from the Scientific American article. There’s a lot of software onboard these space vehicles. In fact, Voyager 1 and 2 each carry six onboard computers, originally organized as a distributed system consisting of three dual-redundant computers: the Computer Command System (CCS), the Attitude Articulation Control System (AACS), and the Flight Data System (FDS). Without these six embedded computers, which have operated continuously for nearly half a century, the two spacecraft would never have reached the Solar System’s outer planets, and all the scientific data collected by the instruments on board the spacecraft would never have made it back to Earth.

The CCS – designed by the Jet Propulsion Laboratory (JPL) in Pasadena, California – controls all major spacecraft systems, monitors the spacecraft’s health, maintains temperatures inside of the spacecraft, manages the AACS and FDS computers, and controls the eleven onboard scientific instruments by sending them commands. The CCS employs an 18-bit instruction word with a 6-bit opcode and a 12-bit address, and it has an 18-bit data word.

To control development costs, the CCS is nearly identical to the embedded computer developed for the Viking spacecraft that went to Mars, with the addition of interface ports for the FDS and AACS. The CCS is constructed entirely of TTL logic chips, because that’s how things were done in the early 1970s; It was the heyday of the 7400 series TTL family, which was dominated by Texas Instruments. The paired CCS computers use dual-redundant plated-wire read/write memory, which works like magnetic-core memory but uses wire plated with a magnetic coating instead of ferrite beads. The CCS is an interrupt-driven computer and runs bare-metal code. There is no operating system.

The AACS has a very similar architecture to the CCS and therefore also traces its lineage to the earlier Viking spacecraft computer. This computer handles attitude control for the spacecraft and controls articulation of the scan platform, which was mounted on a boom to give the spacecraft’s imaging instruments a moving platform for a better field of view. The AACS controls the spacecraft’s boom servomotors and hydrazine thrusters and is responsible for keeping Voyager’s large dish antenna pointed at the Earth so that contact isn’t lost. Superficially, at least, the architecture of the CCS and AACS seem to have more in common with the Digital Equipment Corporation PDP-9 minicomputer that I learned to program in 1971 than it has with the early 4- and 8-bit microprocessors of the day.

The FDS was custom designed for the Voyager spacecraft because JPL needed a faster computer to format, store, and transmit images (the data that we most identify with the Voyager missions) and to send the spacecraft’s science and engineering telemetry data back to Earth. Unlike the other two computer systems used on Voyager, the FDS is not built with TTL chips. It’s the first computer based on CMOS chips to be flown in space.

Instead of plated-wire memory, the FDS employs volatile CMOS RAM for read/write memory. This choice was heretical in JPL spacecraft design back in the day. JPL preferred nonvolatile memory so that the spacecraft computer could survive a temporary power loss. However, the Voyager spacecraft are powered by plutonium-fueled, nuclear-thermoelectric generators, and the FDS had a direct connection to the generator’s output, so a power loss indicates much bigger problems on the spacecraft than a mere computer glitch.

Part of the data formatting performed by the FDS includes forward error correction (FEC) using Golay coding. As the two Voyager spacecraft get more and more distant, their signals become weaker, the radio channel becomes noisier, and so the signal-to-noise ratio falls. Golay coding allows data sent to Earth to survive three bits of reception error per data word. However, Golay coding also doubles the number of bits sent, thus cutting effective channel bandwidth in half.

JPL enhanced the FDS capabilities on Voyager 2 when the original Jupiter/Saturn mission was extended to the outer planets. The enhancements included image compression and a switch to Reed-Solomon FEC for image processing. Reed-Solomon codes incur significantly less overhead than the original Golay FEC code and are now widely used for data storage and communications applications. The Voyager FDS software was a pioneer in its use of this coding algorithm.

Both FDS enhancements allow Voyager 2 to push more data through the increasingly diminished radio bandwidth as the spacecraft travels farther and farther away from Earth, but at a cost. The enhancements require full-time use of the second, redundant FDS computer for the new image-processing algorithms because one FDS computer is no longer sufficient to run all the FDS software. So, the price for the enhancements was a loss of FDS redundancy. It’s important to note that the enhancements were possible only because they could be uploaded to Voyager’s computers as software upgrades.

The CCS, AACS, and FDS constitute a sophisticated, distributed, dual-redundant, embedded computer system that JPL designed and built into the Voyager spacecraft. It was the instruments on the spacecraft that lacked computers and software. This is one of the odd ways that the US builds uncrewed spacecraft for scientific missions. The main mission owner is JPL, which designs and assembles the spacecraft from components made by contractors. JPL is the system integrator. But the JPL spacecraft are trucks or buses that carry instruments to a destination, and those instruments are usually designed and built by a variety of academic consortia and research labs, including the Johns Hopkins Applied Physics Laboratory.

Voyager’s instruments did not have the power budgets or the available time for custom computer development, and microprocessors were far too new at the time, so the electrical engineers working on these projects created simpler systems using hardwired logic.

The eleven instruments on the two identical Voyager spacecraft are:

•         Imaging Science Subsystem: a two-camera video system, with one narrow-angle camera and one wide-angle camera. The system used monochrome, slow-scan vidicon tubes and as many as eight filters per camera in a filter wheel to generate monochrome, color, and UV images.
•         Radio Science Subsystem: used the spacecraft’s radio systems to determine the physical properties of planetary and satellite ionospheres and atmospheres and determine their masses, gravity fields, and densities during encounters with these bodies.
•         Infrared Interferometer Spectrometer: a Michelson interferometer and a single-channel radiometer that measured the composition of planets’ and satellites’ atmospheres.
•         Ultraviolet Spectrometer: measured atmospheric properties and atmospheric radiation in the UV band (400 to 1600 A).
•         Triaxial Fluxgate Magnetometer: designed to investigate the magnetic fields of Jupiter and Saturn, the solar-wind interaction with the magnetospheres of these planets, and the interplanetary magnetic field out to the solar wind boundary and beyond.
•         Plasma Spectrometer: investigated the macroscopic properties of plasma ions and measured electrons in the energy range from 5 eV to 1 keV.
•         Low Energy Charged Particle Instrument: designed to study energetic particles including electrons, protons, alpha particles, and heavier nuclei in both planetary and interplanetary environments.
•         Cosmic Ray Subsystem: a High-Energy Telescope System (HETS) and a Low-Energy Telescope System (LETS) that studied the origin, life history, and dynamic contribution of interstellar cosmic rays, element nucleosynthesis in cosmic-ray sources, the behavior of cosmic rays in the interplanetary medium, and trapped energetic particles in the planetary environment.
•         Planetary Radio Astronomy Investigation: studied the physics of magnetospheric plasma resonances and nonthermal radio emissions using a swept-frequency radio receiver operating in two polarization states at frequencies ranging from 20kHz to 40.5MHz.
•         Photopolarimeter Subsystem: an 8-inch Cassegrain telescope with a polarizer and filters for eight bands in the 2200A to 7300A spectral region that feeds a photomultiplier tube, used to study surface texture and composition of planets, to capture information about the size distribution and composition of the bodies in planetary rings, and to obtain information on atmospheric scattering properties and density for the atmospheres of the planets.
•         Plasma Wave Subsystem: a 16-channel, step-frequency receiver and a low-frequency waveform receiver used to provide continuous, sheath-independent measurements of the electron-density profiles at Jupiter, Saturn, and the other visited planets.

These instruments helped to alter our understanding of the Solar System. We also know from these instruments, at least the ones still powered up and working, that the two Voyager spacecraft have now traveled beyond the Solar System’s boundary and into interstellar space.

In addition to these eleven scientific instruments, the Voyager spacecraft carry a gold-plated LP record that encodes sounds and images, just in case one or both spacecraft are discovered by other civilizations eons from now. One of the sounds on the record is a message from Jimmy Carter, who was president when the Voyagers launched. Carter said, “We cast this message into the cosmos.”

Along with these recordings, we sent these other civilizations early examples of our embedded computer technology, circa the middle 1970s. With their snail-like clock rates and tiny memories, these computers may seem very primitive by today’s standards. But so far, they have shepherded the Voyagers for nearly 50 years, over billions of miles and through intense radiation belts, while continuing to send priceless scientific data back to Earth.

For more information about the Voyager spacecraft and its embedded computer systems, I recommend a wonderful 2019 presentation made by Aaron Cummings, titled “Uptime 15,364 days – The Computers of Voyager.” You’ll find it on YouTube, here .

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Well, hello, Voyager 1! The venerable spacecraft is once again making sense

Nell Greenfieldboyce

Members of the Voyager team celebrate at NASA's Jet Propulsion Laboratory after receiving data about the health and status of Voyager 1 for the first time in months. NASA/JPL-Caltech hide caption

Members of the Voyager team celebrate at NASA's Jet Propulsion Laboratory after receiving data about the health and status of Voyager 1 for the first time in months.

NASA says it is once again able to get meaningful information back from the Voyager 1 probe, after months of troubleshooting a glitch that had this venerable spacecraft sending home messages that made no sense.

The Voyager 1 and Voyager 2 probes launched in 1977 on a mission to study Jupiter and Saturn but continued onward through the outer reaches of the solar system. In 2012, Voyager 1 became the first spacecraft to enter interstellar space, the previously unexplored region between the stars. (Its twin, traveling in a different direction, followed suit six years later.)

Voyager 1 had been faithfully sending back readings about this mysterious new environment for years — until November, when its messages suddenly became incoherent .

NASA's Voyager 1 spacecraft is talking nonsense. Its friends on Earth are worried

It was a serious problem that had longtime Voyager scientists worried that this historic space mission wouldn't be able to recover. They'd hoped to be able to get precious readings from the spacecraft for at least a few more years, until its power ran out and its very last science instrument quit working.

For the last five months, a small team at NASA's Jet Propulsion Laboratory in California has been working to fix it. The team finally pinpointed the problem to a memory chip and figured out how to restore some essential software code.

"When the mission flight team heard back from the spacecraft on April 20, they saw that the modification worked: For the first time in five months, they have been able to check the health and status of the spacecraft," NASA stated in an update.

The usable data being returned so far concerns the workings of the spacecraft's engineering systems. In the coming weeks, the team will do more of this software repair work so that Voyager 1 will also be able to send science data, letting researchers once again see what the probe encounters as it journeys through interstellar space.

After a 12.3 billion-mile 'shout,' NASA regains full contact with Voyager 2

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10 Interesting Facts about the Voyager 1 Probe

October 29, 2017 James Miller Solar System , Space Missions 0

According to some reports, many of the mission scientists working on the Voyager space exploration program are “amazed” that both Voyagers are still functioning after forty years in service. This sentiment becomes clear when one considers that the Voyagers run on technology that was developed in the 1970’s, which incidentally, has not suffered any major breakdowns and malfunctions in four decades.

The fact that Voyager 1 had made it to outer space is a testament to the skill, knowledge, and dedication of the engineers who designed, built, and still operate the craft. Furthermore, Voyager 1 has made major contributions to our knowledge of the outer planets over the years, and is expected to continue collecting and returning data to Earth until about 2025. Below are ten interesting facts about this amazing craft.

Voyager 1 is the furthest space craft from Earth

The image below shows Voyager 1 being propelled into space by a Titan IIIE lift vehicle. Launched on September 5, 1977, sixteen days after Voyager 2 which lifted off on August 20, Voyager 1 is now the furthest manufactured object from Earth, even further than the dwarf planets Eris and V774104, which are 96 AU and about 103 AU away, respectively. From a distance of 140 AU away (as on September 22, 2017), Voyager 1 is still in regular contact with the Deep Space Network, and receiving control inputs and return data. In practice, this means that Voyager 1 is the most distant object in the solar system whose exact location is known at all times.

Voyager 1 was originally part of the Mariner 11 program

When NASA first conceived of a “Grand Tour” of the solar system in the 1960’s, the proposed craft that would conduct the tour was designed to be a part of the Mariner 11 program. However, based on the lessons on solar radiation learned from the Mariner 10 program, (as well as severe budget cuts), the craft was designed to be able to cope more effectively with the strong radiation fields around Jupiter, which it was meant to visit. Eventually, the design and specifications of the proposed craft started to deviate from the Mariner designs so radically that the proposed craft was renamed as Voyager 1.

Voyager 1 has three nuclear reactors that generate power

Voyager 1 is the third craft to reach solar system-escape velocity

After completing its planetary mission in November of 1980, Voyager 1 became one of only a handful of spacecraft to obtain enough velocity (about 17 km/sec) to escape from the solar system, the other craft being Pioneer 10, Pioneer 11, and Voyager 2. Apart from the New Horizons craft, Voyager 1 also had the fastest launch speed; it overtook Voyager 2 a few months after launch, flew past Pioneer 11 in the late 1980’s, and passed Pioneer 10 on February 17, 1998. Incidentally, New Horizons will, despite its high velocity, never overtake either of the two Voyagers.

Voyager 1 discovered the source of Saturn’s excess heat

Voyager 1 detected during the Saturn fly-by that the planet’s upper atmosphere contains only about 7% helium, which was surprising considering its helium abundance was expected to be about 11%, or the value for both the Sun and Jupiter . Investigators are surmising that the heavier helium is sinking downward through the less-dense hydrogen in the planets’ atmosphere creating heat, which might explain why Saturn radiates more heat than it receives from the Sun. Voyager 1 also discovered winds that blow at more than 500 m/sec (1,100 mph) through Saturn’s atmosphere in an easterly direction.

Voyager 1 also discovered volcanoes in the Jovian system

Since it was long thought that Earth is the only body in the solar system on which active volcanoes are present, this image taken by Voyager 1 of an erupting volcano on Jupiter’s moon Io came as a major surprise. Voyager also discovered that material ejected from volcanoes on Io permeates the entire Jovian system, since sulphur, oxygen, and sodium was detected by Voyager 1 right at the outer limits of Jupiter’s magnetosphere, which is the region of space around the system that is affected and influenced by Jupiter’s magnetic field.

Voyager 1 took the first solar system “family portrait”

The assembled mosaic above represents the first ever image of the solar system taken from outside of the solar system. This image was taken by Voyager 1 on February 14, 1990, shortly before the crafts’ imaging equipment was purposely disabled by deleting the software that control the cameras. This was done to conserve both power and computer resources, but also because Earth-based technology to receive and “read” images from the craft are no longer available.

The modified image below shows one small part of the above mosaic. This image is known as the Pale Blue Dot, and it shows Earth as the bright spot at the centre of the blue circle, with Voyager 1 having taken the photo on February 14, 1990 from a distance of 4 billion miles (6.4 billion km). The brown line in which Earth appears is one band of sunlight that is reflecting off a part of the spacecraft.

Voyager 1 is now officially in outer space

While the question of when Voyager 1 had left the solar system , or even if it had left at all, was the subject of heated debate among scientists for several years, most investigators now accept August 25, 2012 as the date on which the craft officially exited the solar system. This was decided based upon the increase of the average density of electrons in the craft’s vicinity, which in turn is based on a solar outburst that had occurred March of 2012, and the frequency of plasma oscillations caused by the outburst. The final conclusion was that since the electron density outside of the Sun’s heliosheath is expected be twice that of the electron density inside it, Voyager must be in the interstellar medium.

Despite the above, Voyager 1 is still in the solar system proper

While many people consider leaving the heliosheath as being synonymous with leaving the solar system,, the fact is that the two are vastly different. The Sun’s heliosheath merely refers to the region of space that is influenced by the Sun’s gravity and radiation, while the term “solar system” refers to the region of space that is inhabited by all the bodies that orbit the Sun.

Based on the above, Voyager 1 is still in the solar system, since it will take another three hundred years or so for it to reach the inner edge of the Oort cloud and another 30,000 years or so for it to exit the Oort cloud. Note that while Voyager 1 is not headed toward any particular star, it will pass within 1.6 light years of the star Gliese 445 (which is approaching us at about 119 km/s (430,000 km/h; 270,000 mph), in about 400,000 years’ time.

Voyager 1 carries a message of love

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Voyager 1 transmitting data again after Nasa remotely fixes 46-year-old probe

Engineers spent months working to repair link with Earth’s most distant spacecraft, says space agency

Earth’s most distant spacecraft, Voyager 1, has started communicating properly again with Nasa after engineers worked for months to remotely fix the 46-year-old probe.

Nasa’s Jet Propulsion Laboratory (JPL), which makes and operates the agency’s robotic spacecraft, said in December that the probe – more than 15bn miles (24bn kilometres) away – was sending gibberish code back to Earth.

In an update released on Monday , JPL announced the mission team had managed “after some inventive sleuthing” to receive usable data about the health and status of Voyager 1’s engineering systems. “The next step is to enable the spacecraft to begin returning science data again,” JPL said. Despite the fault, Voyager 1 had operated normally throughout, it added.

Launched in 1977, Voyager 1 was designed with the primary goal of conducting close-up studies of Jupiter and Saturn in a five-year mission. However, its journey continued and the spacecraft is now approaching a half-century in operation.

Voyager 1 crossed into interstellar space in August 2012, making it the first human-made object to venture out of the solar system. It is currently travelling at 37,800mph (60,821km/h).

Hi, it's me. - V1 https://t.co/jgGFBfxIOe — NASA Voyager (@NASAVoyager) April 22, 2024

The recent problem was related to one of the spacecraft’s three onboard computers, which are responsible for packaging the science and engineering data before it is sent to Earth. Unable to repair a broken chip, the JPL team decided to move the corrupted code elsewhere, a tricky job considering the old technology.

The computers on Voyager 1 and its sister probe, Voyager 2, have less than 70 kilobytes of memory in total – the equivalent of a low-resolution computer image. They use old-fashioned digital tape to record data.

The fix was transmitted from Earth on 18 April but it took two days to assess if it had been successful as a radio signal takes about 22 and a half hours to reach Voyager 1 and another 22 and a half hours for a response to come back to Earth. “When the mission flight team heard back from the spacecraft on 20 April, they saw that the modification worked,” JPL said.

Alongside its announcement, JPL posted a photo of members of the Voyager flight team cheering and clapping in a conference room after receiving usable data again, with laptops, notebooks and doughnuts on the table in front of them.

The Retired Canadian astronaut Chris Hadfield, who flew two space shuttle missions and acted as commander of the International Space Station, compared the JPL mission to long-distance maintenance on a vintage car.

“Imagine a computer chip fails in your 1977 vehicle. Now imagine it’s in interstellar space, 15bn miles away,” Hadfield wrote on X . “Nasa’s Voyager probe just got fixed by this team of brilliant software mechanics.

Voyager 1 and 2 have made numerous scientific discoveries , including taking detailed recordings of Saturn and revealing that Jupiter also has rings, as well as active volcanism on one of its moons, Io. The probes later discovered 23 new moons around the outer planets.

As their trajectory takes them so far from the sun, the Voyager probes are unable to use solar panels, instead converting the heat produced from the natural radioactive decay of plutonium into electricity to power the spacecraft’s systems.

Nasa hopes to continue to collect data from the two Voyager spacecraft for several more years but engineers expect the probes will be too far out of range to communicate in about a decade, depending on how much power they can generate. Voyager 2 is slightly behind its twin and is moving slightly slower.

In roughly 40,000 years, the probes will pass relatively close, in astronomical terms, to two stars. Voyager 1 will come within 1.7 light years of a star in the constellation Ursa Minor, while Voyager 2 will come within a similar distance of a star called Ross 248 in the constellation of Andromeda.

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Contact restored with NASA’s Voyager 1 space probe

Contact restored.

That was the message relieved NASA officials shared after the agency regained full contact with the Voyager 1 space probe, the most distant human-made object in the universe, scientists have announced.

For the first time since November, the spacecraft is returning usable data about the health and status of its onboard engineering systems, NASA said in a news release Monday.

The 46-year-old pioneering probe, now 15.1 billion miles from Earth, has continually defied expectations for its life span as it ventures farther into the  uncharted territory of the cosmos .

More: Voyager 1 is 15 billion miles from home and broken. Here's how NASA is trying to fix it.

Computer experts to the rescue

It wasn't as easy as hitting Control-Alt-Delete, but top experts at NASA and CalTech were able to fix the balky, ancient computer on board the probe that was causing the communication breakdown – at least for now.

A computer problem aboard Voyager 1 on Nov. 14, 2023, corrupted the stream of science and engineering data the craft sent to Earth,  making it unreadable .

Although the radio signal from the spacecraft had never ceased its connection to ground control operators on Earth, that signal had not carried any usable data since November, NASA said. After some serious sleuthing to fix the onboard computer, that changed on April 20, when NASA finally received usable data.

In interstellar space

The probe and its twin, Voyager 2, are the only spacecraft to ever fly in interstellar space (the space between the stars).

Voyager 2 continues to operate normally, NASA reports. Launched  more than 46 years ago , the twin spacecraft are standouts on two fronts: they've operated the longest and traveled the farthest of any spacecraft ever.

Before the start of their interstellar exploration, both probes flew by Saturn and Jupiter, and Voyager 2 flew by Uranus and Neptune.

More: NASA gave Voyager 1 a 'poke' amid communication woes. Here's why the response was encouraging.

They were  designed to last five years but have become the longest-operating spacecraft in history. Both carry  gold-plated copper discs  containing sounds and images from Earth, content that was chosen by a team headed by celebrity astronomer  Carl Sagan .

For perspective, it was the summer of 1977 when the Voyager probes left Earth. "Star Wars" was No. 1 at the box office, Jimmy Carter was in the first year of his presidency, and Elvis Presley had just died.

Contributing: Eric Lagatta and George Petras

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April 27, 2024

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NASA hears from Voyager 1, the most distant spacecraft from Earth, after months of quiet

by Marcia Dunn

NASA has finally heard back from Voyager 1 again in a way that makes sense.

The most distant spacecraft from Earth stopped sending back understandable data last November. Flight controllers traced the blank communication to a bad computer chip and rearranged the spacecraft's coding to work around the trouble.

NASA's Jet Propulsion Laboratory in Southern California declared success after receiving good engineering updates late last week. The team is still working to restore transmission of the science data.

It takes 22 1/2 hours to send a signal to Voyager 1, more than 15 billion miles (24 billion kilometers) away in interstellar space . The signal travel time is double that for a round trip.

Contact was never lost, rather it was like making a phone call where you can't hear the person on the other end, a JPL spokeswoman said Tuesday.

Launched in 1977 to study Jupiter and Saturn, Voyager 1 has been exploring interstellar space — the space between star systems — since 2012. Its twin, Voyager 2, is 12.6 billion miles (20 billion kilometers) away and still working fine.

© 2024 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed without permission.

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NASA's Voyager 1 spacecraft finally phones home after 5 months of no contact

On Saturday, April 5, Voyager 1 finally "phoned home" and updated its NASA operating team about its health.

NASA's interstellar explorer Voyager 1 is finally communicating with ground control in an understandable way again. On Saturday (April 20), Voyager 1 updated ground control about its health status for the first time in 5 months. While the Voyager 1 spacecraft still isn't sending valid science data back to Earth, it is now returning usable information about the health and operating status of its onboard engineering systems. 

Thirty-five years after its launch in 1977, Voyager 1 became the first human-made object to leave the solar system and enter interstellar space . It was followed out of our cosmic quarters by its space-faring sibling, Voyager 2 , six years later in 2018. Voyager 2, thankfully, is still operational and communicating well with Earth. 

The two spacecraft remain the only human-made objects exploring space beyond the influence of the sun. However, on Nov. 14, 2023, after 11 years of exploring interstellar space and while sitting a staggering 15 billion miles (24 billion kilometers) from Earth, Voyager 1's binary code — computer language composed of 0s and 1s that it uses to communicate with its flight team at NASA — stopped making sense.

Related: We finally know why NASA's Voyager 1 spacecraft stopped communicating — scientists are working on a fix

In March, NASA's Voyager 1 operating team sent a digital "poke" to the spacecraft, prompting its flight data subsystem (FDS) to send a full memory readout back home.

This memory dump revealed to scientists and engineers that the "glitch" is the result of a corrupted code contained on a single chip representing around 3% of the FDS memory. The loss of this code rendered Voyager 1's science and engineering data unusable.

The NASA team can't physically repair or replace this chip, of course, but what they can do is remotely place the affected code elsewhere in the FDS memory. Though no single section of the memory is large enough to hold this code entirely, the team can slice it into sections and store these chunks separately. To do this, they will also have to adjust the relevant storage sections to ensure the addition of this corrupted code won't cause those areas to stop operating individually, or working together as a whole. In addition to this, NASA staff will also have to ensure any references to the corrupted code's location are updated.

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On April 18, 2024, the team began sending the code to its new location in the FDS memory. This was a painstaking process, as a radio signal takes 22.5 hours to traverse the distance between Earth and Voyager 1, and it then takes another 22.5 hours to get a signal back from the craft. 

By Saturday (April 20), however, the team confirmed their modification had worked. For the first time in five months, the scientists were able to communicate with Voyager 1 and check its health. Over the next few weeks, the team will work on adjusting the rest of the FDS software and aim to recover the regions of the system that are responsible for packaging and returning vital science data from beyond the limits of the solar system.

Join our Space Forums to keep talking space on the latest missions, night sky and more! And if you have a news tip, correction or comment, let us know at: [email protected].

Robert Lea is a science journalist in the U.K. whose articles have been published in Physics World, New Scientist, Astronomy Magazine, All About Space, Newsweek and ZME Science. He also writes about science communication for Elsevier and the European Journal of Physics. Rob holds a bachelor of science degree in physics and astronomy from the U.K.’s Open University. Follow him on Twitter @sciencef1rst.

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• Robb62 'V'ger must contact the creator. Reply
• Holy HannaH! Couldn't help but think that "repair" sounded extremely similar to the mechanics of DNA and the evolution of life. Reply
• Torbjorn Larsson *Applause* indeed, thanks to the Voyager teams for the hard work! Reply
• SpaceSpinner I notice that the article says that it has been in space for 35 years. Either I have gone back in time 10 years, or their AI is off by 10 years. V-*ger has been captured! Reply

Admin said: On Saturday, April 5, Voyager 1 finally "phoned home" and updated its NASA operating team about its health. The interstellar explorer is back in touch after five months of sending back nonsense data. NASA's Voyager 1 spacecraft finally phones home after 5 months of no contact : Read more

evw said: I'm incredibly grateful for the persistence and dedication of the Voyagers' teams and for the amazing accomplishments that have kept these two spacecrafts operational so many years beyond their expected lifetimes. V-1 was launched when I was 25 years young; I was nearly delirious with joy. Exploring the physical universe captivated my attention while I was in elementary school and has kept me mesmerized since. I'm very emotional writing this note, thinking about what amounts to a miracle of technology and longevity in my eyes. BRAVO!!! THANK YOU EVERYONE PAST & PRESENT!!!

• EBairead I presume it's Fortran. Well done all. Reply

SpaceSpinner said: I notice that the article says that it has been in space for 35 years. Either I have gone back in time 10 years, or their AI is off by 10 years. V-*ger has been captured!

EBairead said: I presume it's Fortran. Well done all.

• View All 13 Comments

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