Engineers regain full control over Voyager 2

A longshot effort by engineers has succeeded in re-establishing full communications with Voyager 2, launched in 1977 and flying outward at the edge of the solar system.

“The Deep Space Network used the highest-power transmitter to send the command (the 100-kw S-band uplink from the Canberra site) and timed it to be sent during the best conditions during the antenna tracking pass in order to maximize possible receipt of the command by the spacecraft,” Voyager project manager Suzanne Dodd told AFP. This so-called “interstellar shout” required 18.5 hours traveling at light speed to reach Voyager, and it took 37 hours for mission controllers to learn whether the command worked, JPL said in a statement.

The probe began returning science and telemetry data at 12:29 am Eastern Time on August 4, “indicating it is operating normally and that it remains on its expected trajectory,” added JPL.

Based on a weak signal received earlier, engineers were confident that the spacecraft was functioning in good order despite the loss in communications, and would automatically re-orient itself properly when it did an automatic reset in October. This attempt however fixed things now.

Regardless, the spacecraft probably only has a few more more years of operations before its nuclear powered source finally runs out sometime after 2025.

NASA detects weak signal from Voyager 2

Though communications with Voyager 2 have not been re-established, JPL engineers using NASA’s Deep Space Network of antennas have detected a weak signal from Voyager 2 that indicates the spacecraft is still functioning.

Using multiple antennas, NASA’s Deep Space Network (DSN) was able to detect a carrier signal from Voyager 2. A carrier signal is what the spacecraft uses to send data back to Earth. The signal is too faint for data to be extracted, but the detection confirms that the spacecraft is still operating. The spacecraft also continues on its expected trajectory. Although the mission expects the spacecraft to point its antenna at Earth in mid-October, the team will attempt to command Voyager sooner, while its antenna is still pointed away from Earth. To do this, a DSN antenna will be used to “shout” the command to Voyager to turn its antenna. This intermediary attempt may not work, in which case the team will wait for the spacecraft to automatically reset its orientation in October.

The hope is that new commands to re-orient, sent by the strongest signal possible, might be heard by the spacecraft, causing it to obey now. If not, this weak signal from Voyager 2 still suggests that the October reset will occur as normal and engineers will be able to recover communications then.

Contact lost with Voyager 2, hopefully temporarily

New but planned commands to Voyager 2, presently flying beyond the solar system, caused the spacecraft to point its antenna incorrectly so that communications with Earth have been lost.

A series of planned commands sent to NASA’s Voyager 2 spacecraft on July 21 inadvertently caused the antenna to point 2 degrees away from Earth. As a result, Voyager 2 is currently unable to receive commands or transmit data back to Earth.

Voyager 2 is located almost 12.4 billion miles (19.9 billion kilometers) from Earth and this change has interrupted communication between Voyager 2 and the ground antennas of the Deep Space Network (DSN). Data being sent by the spacecraft is no longer reaching the DSN, and the spacecraft is not receiving commands from ground controllers.

The spacecraft is also programmed to periodically reset its orientation so that its antenna points to Earth, with the next reset scheduled for October 15th. Engineers hope that at that point contact will be recovered.

If not, this incident will mark the end of the mission, which launched in 1977 and has been functioning for 46 years as it has made close fly-bys of Jupiter, Saturn, Uranus, and Neptune, and then eventually entering interstellar space.

Engineers extend Voyager-2’s life by tapping into reserve power supply

Engineers have begun using a backup power supply on the Voyager-2 spacecraft — launched in 1977 and presently traveling in interstellar space — in order to extend the life of one of its five instruments one additional year.

To help keep those instruments operating despite a diminishing power supply, the aging spacecraft has begun using a small reservoir of backup power set aside as part of an onboard safety mechanism. The move will enable the mission to postpone shutting down a science instrument until 2026, rather than this year.

The solution is only temporary, as the end of the mission is inevitable as its radioisotope thermoelectric generator (RTG) was only designed to provide power for about a half century (!). As time passes its power supply slowly declines, forcing engineers in recent years to shut down other systems to allow the science instruments to operate. That all the other systems on both Voyager-1 and Voyager-2 remained operational until the end of their RTGs tells us how well these spacecraft were built by their 1970s creators.

Assuming this works, engineers will do the same thing on Voyager-1 sometime next year. In both cases, however, power from the RTGs will likely run out entire sometime in the next 5-10 years, ending the missions.

After 50 years Edward Stone retires as the project scientist for Voyagers 1 and 2

Edward Stone, the only project scientist the interstellar spacecraft Voyagers 1 and 2 have ever known, has now retired after 50 years service.

Stone accepted scientific leadership of the historic mission in 1972, five years before the launch of its two spacecraft, Voyager 1 and Voyager 2. Under his guidance, the Voyagers explored the four giant planets and became the first human-made objects to reach interstellar space, the region between the stars containing material generated by the death of nearby stars.

Until now, Stone was the only person to have served as project scientist for Voyager, maintaining his position even while serving as director of NASA’s Jet Propulsion Laboratory in Southern California from 1991 to 2001. JPL manages the Voyager mission for NASA. Stone retired from JPL in 2001 but continued to serve as the mission’s project scientist.

The new Voyager project scientist however is not new to the project.

Linda Spilker will succeed Stone as Voyager’s project scientist as the twin probes continue to explore interstellar space. Spilker was a member of the Voyager science team during the mission’s flybys of Jupiter, Saturn, Uranus, and Neptune. She later became project scientist for NASA’s now-retired Cassini mission to Saturn, and rejoined Voyager as deputy project scientist in 2021.

Signal to Voyager-2 confirms upgrade of NASA’s Deep Space Network

After months of downtime in order to install a major and very badly needed upgrade to NASA’s Deep Space Network (DSN) (the worldwide array of radio dishes used to communicate with planetary probes throughout the solar system) a test command to Voyager-2 beyond the orbit of Pluto was sent, received, and executed successfully this week, proving the upgrade is working.

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.

Among the upgrades to DSS43, as the dish is known, are two new radio transmitters. One of them, which is used to talk with Voyager 2, hasn’t been replaced in over 47 years. Engineers have also upgraded heating and cooling equipment, power supply equipment, and other electronics needed to run the new transmitters.

The successful call to Voyager 2 is just one indication that the dish will be back online in February 2021.

The upgrade has been overdue for years, and is essential to provide sufficient communications capability for the future interplanetary mission presently planned.

Upgrades to Deep Space Network to block commands to Voyager 2

A scheduled eleven month upgrade to one of the three Deep Space Network antennas used to communicate with planetary missions will prevent scientists from sending commands to Voyager 2 during that time period.

Data will still be downloaded, but if anything should go wrong, such as happened in January, it will be impossible to do anything about it. In January engineers were able to troubleshoot the problem and upload corrections. During these upgrades a fix will have to wait. To reduce the chance of serious issue, engineers will put Voyager 2 into a more dormant state during this time period.

The repairs are essential however, even if it means we lose Voyager 2. This network must work for all the other Moon and Mars missions planned for the next few decades, and an upgrade has been desperately needed for years.

Voyager-2 back in action

Engineers announced yesterday that Voyager-2 has resumed science operations after going into safe mode in late January.

“Mission operators report that Voyager 2 continues to be stable and that communications between Earth and the spacecraft are good,” agency officials wrote in a mission update yesterday. “The spacecraft has resumed taking science data, and the science teams are now evaluating the health of the instruments following their brief shut-off.”

Still ticking after 42 years in space. Take that, Timex!

Voyager 2 in safe mode

After forty years of operation and successfully leaving the solar system, Voyager 2 has experienced a technical issue that caused it to go into safe mode.

According to NASA, Voyager 2 failed to perform a scheduled maneuver on Saturday January 25. The craft was due to rotate a full 360 degrees to calibrate its magnetic field instrument, but for some reason the action was delayed. That in turn meant that two particularly power-hungry systems were left running at the same time, which overdrew the available power supply.

…As of January 28, the team managed to turn off one of those high-power systems, allowing some scientific instruments to be switched back on. Engineers are currently analyzing data to figure out the status of the rest of the systems, to work out how to turn off the second one and return the craft to normal operations.

Interstellar space, as seen by both Voyager spacecraft

Today a suite of new science papers were published outlining what scientists learned when Voyager 2 joined Voyager 1 in interstellar space last November.

The Sun’s heliosphere is like a ship sailing through interstellar space. Both the heliosphere and interstellar space are filled with plasma, a gas that has had some of its atoms stripped of their electrons. The plasma inside the heliosphere is hot and sparse, while the plasma in interstellar space is colder and denser. The space between stars also contains cosmic rays, or particles accelerated by exploding stars. Voyager 1 discovered that the heliosphere protects Earth and the other planets from more than 70% of that radiation.

The data also shows that Voyager 2, which exited the heliosphere somewhat perpendicular to its direction of travel, is still in the transitional zone between the heliosphere and interstellar space. Voyager 1 exited out the head of the heliosphere, so its transitional zone was compressed and shorter.

The real achievement of these results however is that they were obtainable at all. For both spacecraft to be functioning so well after forty years in space, and able to get their data back to Earth from distances more than 11 billion miles, is a true testament to the grand engineering that went into their design and construction.

They built well in the mid-twentieth century.

Engineers adjust Voyagers 1 & 2 because of steadily dropping power

In recognition that the available power on both Voyager 1 and Voyager 2 continues to drop due to the age of the spacecraft, engineers have decided to make some major changes in how they operate both spacecraft.

For example, to save power on Voyager 2 they have turned off the heaters for the instrument that confirmed last year that the spacecraft had entered interstellar space. Even so, the instrument is still functioning and sending back data. It is expected it will continue to work for some time before finally succumbing to the cold of deep space.

They have also decided to reactivate the back-up thrusters on Voyager 2, just as they did with Voyager 1 in 2017.

Another challenge that engineers have faced is managing the degradation of some of the spacecraft thrusters, which fire in tiny pulses, or puffs, to subtly rotate the spacecraft. This became an issue in 2017, when mission controllers noticed that a set of thrusters on Voyager 1 needed to give off more puffs to keep the spacecraft’s antenna pointed at Earth. To make sure the spacecraft could continue to maintain proper orientation, the team fired up another set of thrusters on Voyager 1 that hadn’t been used in 37 years.

Voyager 2’s current thrusters have started to degrade, too. Mission managers have decided to make the same thruster switch on that probe this month. Voyager 2 last used these thrusters (known as trajectory correction maneuver thrusters) during its encounter with Neptune in 1989.

It is thirty years since those thusters on Voyager 2’s were used. If they work it will be an incredible testament to the engineers who designed both spacecraft.

Voyager 2 enters interstellar space

The Voyager 2 spacecraft, launched in 1977, has entered interstellar space, becoming the second human spacecraft to achieve this.

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.

Voyager 2 now is slightly more than 11 billion miles (18 billion kilometers) from Earth. Mission operators still can communicate with Voyager 2 as it enters this new phase of its journey, but information – moving at the speed of light – takes about 16.5 hours to travel from the spacecraft to Earth. By comparison, light traveling from the Sun takes about eight minutes to reach Earth.

When I first wrote about these spacecraft in the 1990s, it was thought that Voyager 2 would probably not exit the solar system until the 2020s, meaning that its nuclear power source might die before that happened. That it has happened now, so much earlier, helps map the size of the heliosphere as well as the pressure that might be placed upon it by the interstellar medium

Data from Voyager 2 suggests it is entering interstellar space

New data since August from Voyager 2 now suggests it is finally leaving the heliosphere of the solar system and entering interstellar space.

Since late August, the Cosmic Ray Subsystem instrument on Voyager 2 has measured about a 5 percent increase in the rate of cosmic rays hitting the spacecraft compared to early August. The probe’s Low-Energy Charged Particle instrument has detected a similar increase in higher-energy cosmic rays.

Cosmic rays are fast-moving particles that originate outside the solar system. Some of these cosmic rays are blocked by the heliosphere, so mission planners expect that Voyager 2 will measure an increase in the rate of cosmic rays as it approaches and crosses the boundary of the heliosphere.

In May 2012, Voyager 1 experienced an increase in the rate of cosmic rays similar to what Voyager 2 is now detecting. That was about three months before Voyager 1 crossed the heliopause and entered interstellar space.

The scientists warn that there is great uncertainty here, and that the actual transition into interstellar space might take longer than with Voyager 1 since Voyager 2 is traveling in a different direction and is leaving during a different time in the solar cycle.

Hubble takes a look at both Voyagers’ interstellar path

Using the Hubble Space Telescope astronomers have taken a peek at the interstellar material that the two Voyager spacecraft will travel through as they move out and leave the solar system in the coming decades.

Voyager 1 is 13 billion miles from Earth, making it the farthest human-made object ever built. In about 40,000 years, after the spacecraft will no longer be operational and will not be able to gather new data, it will pass within 1.6 light-years of the star Gliese 445, in the constellation Camelopardalis. Its twin, Voyager 2, is 10.5 billion miles from Earth, and will pass 1.7 light-years from the star Ross 248 in about 40,000 years.

For the next 10 years, the Voyagers will be making measurements of interstellar material, magnetic fields, and cosmic rays along their trajectories. Hubble complements the Voyagers’ observations by gazing at two sight lines along each spacecraft’s path to map interstellar structure along their star-bound routes. Each sight line stretches several light-years to nearby stars. Sampling the light from those stars, Hubble’s Space Telescope Imaging Spectrograph measured how interstellar material absorbed some of the starlight, leaving telltale spectral fingerprints.

Hubble found that Voyager 2 will move out of the interstellar cloud that surrounds the solar system in a couple thousand years. The astronomers, based on Hubble data, predict that the spacecraft will spend 90,000 years in a second cloud before passing into a third interstellar cloud.

This is very clever science. It allows data from Hubble to complement the data from the two Voyager spacecraft to better understand the interstellar regions that surround our solar system.

On August 13, 2012, Voyager 2 became the longest-operating spacecraft in history, finally topping Pioneer 6, which was launched on Dec. 16, 1965, and sent its last signal back on Dec. 8, 2000.

On August 13, 2012, Voyager 2 became the longest-operating spacecraft in history, finally topping Pioneer 6, which was launched on Dec. 16, 1965, and sent its last signal back to Earth on Dec. 8, 2000.

And Voyager 2, along with its partner Voyager 1, are still working, and engineers hope they will still be working for another eight to twelve years, enough time for them to leave the solar system and enter interstellar space.