Author: Denise Hill

Since November 2023, NASA’s Voyager 1 spacecraft has been sending a steady radio signal to Earth, but the signal does not contain usable data. The source of the issue appears to be with one of three onboard computers, the flight data subsystem (FDS), which is responsible for packaging the science and engineering data before it’s sent to Earth by the telemetry modulation unit.

On March 3, the Voyager mission team saw activity from one section of the FDS that differed from the rest of the computer’s unreadable data stream. The new signal was still not in the format used by Voyager 1 when the FDS is working properly, so the team wasn’t initially sure what to make of it. But an engineer with the agency’s Deep Space Network, which operates the radio antennas that communicate with both Voyagers and other spacecraft traveling to the Moon and beyond, was able to decode the new signal and found that it contains a readout of the entire FDS memory.

The FDS memory includes its code, or instructions for what to do, as well as variables, or values used in the code that can change based on commands or the spacecraft’s status. It also contains science or engineering data for downlink. The team will compare this readout to the one that came down before the issue arose and look for discrepancies in the code and the variables to potentially find the source of the ongoing issue.

This new signal resulted from a command sent to Voyager 1 on March 1. Called a “poke” by the team, the command is meant to gently prompt the FDS to try different sequences in its software package in case the issue could be resolved by going around a corrupted section.

Because Voyager 1 is more than 15 billion miles (24 billion kilometers) from Earth, it takes 22.5 hours for a radio signal to reach the spacecraft and another 22.5 hours for the probe’s response to reach antennas on the ground. So the team received the results of the command on March 3. On March 7, engineers began working to decode the data, and on March 10, they determined that it contains a memory readout.

The team is analyzing the readout. Using that information to devise a potential solution and attempt to put it into action will take time.

News Media Contact
Calla Cofield
Jet Propulsion Laboratory, Pasadena, Calif.
626-808-2469
calla.e.cofield@jpl.nasa.gov

The Department of Defense has confirmed that NASA’s Thermosphere Ionosphere Mesosphere Energetics and Dynamics Mission (TIMED) spacecraft and the Russian Cosmos 2221 satellite passed each other safely in orbit at about 1:34 a.m. EST on Wednesday, Feb. 28. NASA has confirmed that TIMED is functioning. While the two non-maneuverable satellites will approach each other again, this was their closest pass in the current predicted orbit determinations, as they are gradually moving apart in altitude.

The TIMED mission studies the influence of the Sun and of human activity on Earth’s mesosphere and lower thermosphere/ionosphere. The region is a gateway between Earth and space, where the Sun’s energy is first deposited into Earth’s environment.

The Department of Defense is monitoring a potential collision between NASA’s Thermosphere Ionosphere Mesosphere Energetics and Dynamics Mission (TIMED) spacecraft and the Russian Cosmos 2221 satellite. The two non-maneuverable orbiting spacecraft are expected to make their closest pass at about 1:30 a.m. EST on Wednesday, Feb. 28, at an altitude of about 373 miles (600 km). Although the spacecraft are expected to miss each other, a collision could result in significant debris generation. NASA and the Department of Defense will continue to monitor the situation.

The TIMED science mission studies the influence of the Sun and of human activity on Earth’s mesosphere and lower thermosphere/ionosphere. The region is a gateway between Earth and space, where the Sun’s energy is first deposited into Earth’s environment.

UPDATED Aug. 4, 2023: NASA has reestablished full communications with Voyager 2.

The agency’s Deep Space Network facility in Canberra, Australia, sent the equivalent of an interstellar “shout” more than 12.3 billion miles (19.9 billion kilometers) to Voyager 2, instructing the spacecraft to reorient itself and turn its antenna back to Earth. With a one-way light time of 18.5 hours for the command to reach Voyager, it took 37 hours for mission controllers to learn whether the command worked. At 12:29 a.m. EDT on Aug. 4, 2023, the spacecraft began returning science and telemetry data, indicating it is operating normally and that it remains on its expected trajectory.

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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.

Voyager 2 is programmed to reset its orientation multiple times each year to keep its antenna pointing at Earth; the next reset will occur on Oct. 15, which should enable communication to resume. The mission team expects Voyager 2 to remain on its planned trajectory during the quiet period.

Voyager 1, which is almost 15 billion miles (24 billion kilometers) from Earth, continues to operate normally.

After more than 15 years of scientific discoveries, NASA’s Aeronomy of Ice in the Mesosphere, or AIM, spacecraft is no longer supporting operations after experiencing issues with its battery.

AIM’s batteries initially started to decline in 2019, but the Earth-studying spacecraft continued to return a significant amount of data. Now, with further decline in the battery power, the spacecraft currently is not able to receive commands or collect data.

Launched in 2007, AIM has studied polar mesospheric clouds, also known as night-shining or noctilucent clouds, from its orbit 312 miles above Earth. Its data have changed scientists’ understanding of the causes and formation of the clouds, leading to 379 peer-reviewed scientific papers. AIM – originally slated to operate for two years – completed its primary mission in 2009 and has been in extended operations status since then.

The AIM team will continue to monitor AIM’s communication for two weeks in case the spacecraft is able to reboot and transmit a signal.

By Mara Johnson-Groh
NASA Goddard Space Flight Center, Greenbelt, Md

NASA’s Interstellar Boundary Explorer (IBEX) is fully operational after the mission team successfully reset the spacecraft on March 2.

To take the spacecraft out of a contingency mode it entered last month, the mission team performed a firecode reset (which is an external reset of the spacecraft) instead of waiting for the spacecraft to perform an autonomous reset and power cycle on March 4. The decision took advantage of a favorable communications environment around IBEX’s perigee – the point in the spacecraft’s orbit where it is closest to Earth.

After the firecode reset, command capability was restored. IBEX telemetry shows that the spacecraft is fully operational and functioning normally.

Launched on Oct. 19, 2008, IBEX is a small explorer NASA mission tasked with mapping the boundary where winds from the Sun interact with winds from other stars. IBEX, the size of a bus tire, uses instruments that look toward the interstellar boundary from a nine-day orbit around Earth.

 

NASA’s Interstellar Boundary Explorer (IBEX) experienced a flight computer reset during a planned contact and the spacecraft went into contingency mode on Feb. 18.

While fight computer resets have happened before, this time the team lost the ability to command the spacecraft during the subsequent reset recovery. The team also was unsuccessful in regaining command capability by resetting ground systems hardware and software.

Flight software still is running, and the spacecraft systems appear to be functional. However, while uplink signals are reaching the spacecraft, commands are not processing.

If the mission team’s efforts to find and remedy the loss of command capability remain unsuccessful, IBEX will perform an autonomous reset and power cycle on March 4.

NASA will provide additional information on IBEX following the reset unless the agency is able to find a solution before.

By Denise Hill

NASA’s Science Mission Directorate, Japan’s Institute of Space and Astronautical Science (ISAS), and the Japan Aerospace Exploration Agency (JAXA) are determining how to move forward with the joint Geotail mission since discovering the spacecraft’s last operational data recorder has failed.

Originally, Geotail was equipped with two data recorders to collect the mission’s scientific data. One data recorder failed in 2012 after 20 years of gathering information about the plasma environment around Earth. The remaining data recorder continued collecting data for 10 more years until it experienced an anomaly on June 28, 2022.

The team at JAXA discovered the error with the recorder and have been performing tests to investigate the cause and extent of the damage. Ongoing attempts to recover the recorder have been unsuccessful. Without a functioning recorder, the science data from the U.S. instruments can no longer be collected or downlinked. NASA, ISAS, and JAXA are deciding the best path forward for the mission given the failure.

Geotail launched on July 24, 1992, from Cape Canaveral Air Force Station in Florida, with the primary goal of studying the structure and dynamics of the tail region of the Earth’s magnetosphere – the area of space surrounding Earth that is controlled by Earth’s magnetic field – using a comprehensive set of scientific instruments. With an elongated orbit, Geotail has spent the last 30 years sailing through the invisible boundaries of the magnetosphere, gathering data on the physical process at play there. Geotail has made many scientific breakthroughs, including helping scientists better understand what causes material from the Sun to pass into the magnetosphere. It has also made discoveries outside its intended scope, such as identifying oxygen, silicon, sodium, and aluminum in the lunar atmosphere.

By Mara Johnson-Groh
NASA’s Goddard Space Flight Center, Greenbelt, Md.

I recently had the honor of giving the laureate lecture on behalf of Eugene “Gene” Parker, winner of the Crafoord Prize in Astronomy. It was one of the biggest moments of my career. It was also one of the hardest.

Gene received the award in 2020 “for pioneering and fundamental studies of the solar wind and magnetic fields from stellar to galactic scales,” however, due to the pandemic, the official prize ceremony in Lund, Sweden, was postponed for two years. Since Gene was unable to travel, a special ceremony at Gene’s home was hosted by the University of Chicago in November 2021 where I presented him with the Crafoord medal.

Gene was a remarkable man and I knew him personally, which should have made talking about him during the public lecture easier. During his time as a scientist, he authored four books and more than 400 scientific peer-reviewed papers – many as the sole author. He also won a host of awards and honors, including the prestigious and coveted Crafoord Prize.

The Crafoord Prize is the highest honor awarded in the field of astronomy. It is the Nobel Prize equivalent for the field and carries with it a cash prize of over $600,000.

Known as the father of heliophysics, Gene’s discoveries are foundational to what we know about space weather and how stars behave. His level of brilliance is rare – you see it once, maybe twice, in a lifetime, if you’re lucky. He described the discovery of the solar wind as “simple.” It was derived from just four lines of algebra.

Gene’s passing on March 15, 2022, made the assignment of giving the lecture on his behalf even harder. I lost a friend and mentor, Gene’s family lost a husband and father, and humanity lost a legend.

Since I knew Gene personally, it should have made talking about him easier. How exactly does one describe the person that discovered the solar wind and changed the course of astronomy with his magnetic field findings? How in the world do I accurately describe and articulate Gene’s genius? I desperately wanted to do it right, and as I wrote and rewrote what I was going to say I realized that words in and of themselves were inadequate.

Slideshow image credits: NASA/JHU APL/University of Chicago/Glenn Benson/Nicola Fox/Noah Loh/Eric Parker

In 2017, the Solar Probe Plus mission was renamed Parker Solar Probe in honor of Gene. It was the first time a NASA mission has ever been named for a living person. In 2018, I stood with Gene and we watched in awe (I screamed and cheered, and he stared silently mesmerized) as Gene’s namesake mission launched and began its journey. Since its launch, Parker has been continuously setting and breaking records, including fastest human-made object and closest human-made object to the Sun. It has studied comets, returned valuable data on the planet Venus, and provided new information about the dust near our Sun.

On April 28, 2021, Parker Solar Probe flew through the Sun’s upper atmosphere – the corona – and sampled particles and magnetic fields there. In other words, Parker Solar Probe “touched” the Sun. The mission named after Gene and that built upon his work touched the Sun.

During the laureate lecture for the Crafoord Symposium, I talked about Gene and what he meant to me. I also talked about Parker Solar Probe’s accomplishments. I realized that the science could say and do what I couldn’t – properly honor Gene. Parker Solar Probe is a one-of-a-kind mission that has accomplished feats beyond what the world thought was possible – and it’s not done yet. Gene Parker was a one-of-a-kind man that accomplished feats unimaginable in his time and his work will continue to be the foundation that produces bigger and bolder discoveries.

By Nicola Fox
Heliophysics Division Director, NASA HQ, Washington