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Space Exploration

Voyager 1 Reaches Out After Decades with 1981 Device

By Jonathan Bala November 4, 2024

Voyager 1 Reaches Out After Decades with a 1981 Device

The Voyager mission has surpassed all expectations. Originally designed for a brief, focused study of Jupiter and Saturn, Voyager 1 has continued to travel outward and now provides humanity with information from interstellar space. Despite nearly half a century in space and low power levels, Voyager 1, equipped with a backup transmitter from 1981, recently re-established communication after a system issue. This resilience highlights NASA’s strategic design and the enduring spirit of human exploration.

Summary

Mission Background: Launched in 1977, Voyager 1 was initially meant to study Jupiter and Saturn but extended its mission to explore beyond the solar system.
Current Position: Voyager 1 is now over 15 billion miles from Earth, in interstellar space, traveling at about 38,000 mph.
Communication Challenges: Recently, Voyager 1’s primary radio transmitter turned off unexpectedly, halting communication with Earth.
Backup Activation: NASA successfully reconnected with Voyager 1 through an older backup transmitter last used in 1981.
Radiation in Interstellar Space: The spacecraft endures high levels of radiation in interstellar space, which could have unforeseen effects on its systems.
Future of the Mission: With limited power, NASA aims to continue operations with Voyager 1 through 2025 by carefully managing energy use.
NASA’s Deep Space Network: This network played a crucial role in re-establishing communication, picking up faint signals from Voyager 1’s backup system.
Resilience of Voyager: This nearly 50-year-old mission exemplifies human ingenuity and the durability of NASA’s engineering.

We’re all about long-distance commitment… with the Deep Space Network!

Since launching in 1977, my twin and I are now the two farthest human-made objects from Earth. Traveling through interstellar space, we still communicate with our teams back home thanks to the DSN. -V2 pic.twitter.com/YBtlMatPBV

— NASA Voyager (@NASAVoyager) October 23, 2024

The Incredible Journey of Voyager 1: An Exploration Beyond the Stars

In 1977, NASA launched Voyager 1 as part of a mission to explore the outer planets. Voyager 1, along with its twin Voyager 2, was primarily designed to study Jupiter and Saturn, their moons, and Saturn’s rings. Originally, the mission was intended to last only five years. However, after exceeding expectations with groundbreaking observations, NASA extended the mission to explore Uranus and Neptune.

In August 2012, Voyager 1 became the first human-made object to enter interstellar space—a region outside the heliosphere (the bubble-like region dominated by solar wind). This historic milestone marked a new chapter, as Voyager 1 began collecting data on the particles and magnetic fields present between stars.

According to NASA, “Voyager 1 and 2 are the only spacecraft operating outside of the heliosphere, exploring the vast unknown” (NASA Mission).

At approximately 15.4 billion miles from Earth, Voyager 1 faces the challenge of operating on limited power. As the spacecraft generates around 4 fewer watts of power each year, NASA has had to shut down non-essential systems to keep it running.

On October 16, 2024, mission control sent a command to activate a heater on Voyager 1. Two days later, however, they realized something was amiss when the spacecraft failed to respond. By October 19, communication had completely ceased. This unexpected issue triggered the fault protection system, which shut down Voyager’s X-band transmitter—its main line of communication.

The Role of the S-Band Transmitter

Engineers quickly resorted to a lesser-used S-band transmitter, last activated in 1981. Using NASA’s Deep Space Network (DSN)—a trio of massive ground-based antennas positioned across Earth to communicate with distant space probes—they managed to pick up a faint signal from the backup transmitter. This outcome was uncertain; given the spacecraft’s distance and age, they had no guarantee that the backup would still function after decades.

“All the decisions we will have to make going forward are going to require a lot more analysis and caution than they once did,” said Voyager project manager Suzanne Dodd in a recent NASA update (NASA Voyager Blog).

Voyager’s Resilience and NASA’s Strategic Planning

Key Milestones of the Voyager Mission

Year	Milestone
1977	Voyager 1 and 2 launched
1979	Jupiter flyby: Extensive study of Jupiter’s moons
1980	Saturn flyby: Discovery of complex ring systems
1989	Neptune flyby: Completion of planetary tour
2012	Voyager 1 enters interstellar space
2024	Reconnects through 1981 transmitter

The Voyager mission is a testament to the durability of NASA’s engineering. Each critical milestone along Voyager 1’s journey has provided invaluable data, transforming our understanding of planetary systems and interstellar space.

The ongoing mission requires precise power management due to the limited energy available from Voyager’s Radioisotope Thermoelectric Generators (RTGs), which convert the heat from radioactive decay into electricity. NASA anticipates that power constraints may require shutting down even more systems, aiming to keep Voyager operational until at least 2025.

“Voyager’s survival is a story of resilience, patience, and innovation. Every step forward is an uncharted adventure,” says Suzanne Dodd, reaffirming NASA’s commitment to explore the unknown.

Voyager 1 Reaches Out After Decades with 1981 Device — Voyager 1 is traveling away from the solar system. It moves at a speed of over 38,000 miles per hour. It is the farthest object made by humans from Earth. NASA and JPL-Caltech provided this information in a graphic.

Power Management Plan

Component	Priority Level	Power Requirement
Communication System	High	10 watts
Science Instruments	Medium	6 watts
Heater System	Low	3 watts

Enduring the Rigors of Interstellar Space

Voyager 1’s journey into interstellar space brought it into an environment filled with high-energy particles. Unlike the solar system, where the heliosphere provides some level of protection, interstellar space is largely unshielded, exposing Voyager to intense cosmic radiation.

According to a NASA report on interstellar travel (NASA Science), “Interstellar space is an alien environment, one where cosmic rays reign supreme.”

Despite its age, Voyager 1 continues to collect data on cosmic rays, interstellar plasma density, and magnetic fields. Each new piece of information aids scientists in understanding the characteristics of interstellar space.

For example, Voyager 1 detected a high concentration of charged particles when it crossed the heliopause, providing insights into how solar winds interact with interstellar matter. This data offers clues about the broader galaxy and may inform future deep-space missions.

The Voyager mission has captured the world’s imagination. Voyager 1 and 2 carry a golden record that includes sounds, music, and images from Earth—a message intended for any extraterrestrial civilization that might encounter the probes. This gesture symbolizes humanity’s desire to connect with the unknown.

The legacy of Voyager has inspired modern space missions, including NASA’s Artemis program and the development of nuclear propulsion technologies, which could reduce travel times for deep-space missions in the future. According to NASA, “The achievements of Voyager are a foundation on which we build our dreams of interstellar exploration.”

NASA hopes to extend Voyager 1’s mission through 2025 by optimizing power use and continuing to troubleshoot any new challenges. Even after the spacecraft can no longer send data, its trajectory will carry it further into the unknown, potentially lasting billions of years as a silent ambassador of Earth.

Voyager 1’s achievements demonstrate the resilience of well-engineered technology and the relentless drive of human exploration. As NASA’s oldest active mission, Voyager’s journey through interstellar space is a testament to innovation and curiosity. While communication with the probe may become increasingly difficult, its legacy will inspire generations of scientists and engineers to continue exploring the cosmos.

References

NASA JPL
NASA – Deep Space Network
NASA – Science Mission Directorate
NASA – Voyager Telemetry Data Investigation
NASA Blog on Voyager

#Voyager1, #NASA, #SpaceExploration, #InterstellarSpace, #DeepSpaceNetwork, #CosmicJourney, #JupiterMission, #SaturnMission, #GoldenRecord, #Heliopause, #ScienceAndTechnology, #SpaceEngineering, #NASAExploration, #HumanCuriosity, #MilkyWay

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Space Exploration

NASA Shuts Down Voyager 2 Science Instrument: What It Means for Space Exploration

By Jonathan Bala October 3, 2024

NASA Shuts Down Voyager 2 Science Instrument: What It Means for Space Exploration

NASA has shut down the plasma science instrument on Voyager 2 to save power. The remaining four instruments will continue gathering data in interstellar space. The mission has provided groundbreaking information about the outer planets and the heliosphere. Voyager 2, launched in 1977, is over 12.8 billion miles from Earth and still communicating. Both Voyager 1 and 2 have entered interstellar space, marking a historic achievement in space exploration.

Summary

Voyager 2 launched in 1977 as part of NASA’s ambitious Grand Tour of the outer planets.
Powered by plutonium-based RTGs, both Voyager spacecraft are slowly losing power.
NASA decided to shut down the plasma science instrument on Voyager 2 to conserve energy for other tools.
The remaining four instruments will continue to study the interstellar medium and outer heliosphere.
Voyager 2 is over 20.5 billion kilometers away, moving at about 15 km/second.
The twin Voyagers provided unprecedented images and data from Jupiter, Saturn, Uranus, and Neptune.
The RTGs lose about 4 watts per year, and by the 2030s, most instruments will be offline.
Voyager 2 entered interstellar space on November 5, 2018, following Voyager 1, which crossed in 2012.
The plasma science instrument was key in detecting the heliopause, marking the boundary between our solar system and interstellar space.
The Voyager missions remain NASA’s longest-running mission, providing invaluable data about the outer planets and beyond.

NASA Shuts Down Voyager 2 Science Instrument What It Means for Space Exploration

NASA’s Decision to Shut Down Voyager 2’s Plasma Science Instrument

NASA’s decision to power down the plasma science instrument on Voyager 2 marks a vital moment in the spacecraft’s remarkable 47-year mission. As the spacecraft continues its journey through interstellar space, it faces an ever-decreasing power supply from its radioisotope thermoelectric generators (RTGs). Shutting down the plasma science instrument ensures that Voyager 2’s other critical tools can continue to function for as long as possible.

The plasma science instrument played a crucial role in measuring ionized particles and determining the spacecraft’s transition into interstellar space. However, its limited utility in recent years, due to the orientation of Voyager 2 relative to the plasma flow in space, made it the most logical choice for deactivation. This action reflects NASA’s ongoing efforts to manage Voyager 2’s power supply and maintain the mission’s scientific output.

Voyager 2’s remaining instruments will continue gathering data, offering scientists a wealth of information about the outer heliosphere and the interstellar medium. These tools include a magnetometer, a charged particle instrument, a cosmic ray system, and a plasma wave detector. Each of these instruments provides unique insights into the space environment outside our solar system, helping researchers understand phenomena such as the interstellar magnetic field and cosmic rays.

Voyager 2’s journey began in 1977, when it was launched as part of NASA’s Grand Tour of the outer planets. The spacecraft was designed to take advantage of a rare planetary alignment, which occurs only once every 175 years, allowing it to visit Jupiter, Saturn, Uranus, and Neptune. The mission’s goal was to study these planets and their moons in detail, providing the first-ever close-up views of the outer solar system.

During its flybys, Voyager 2 made numerous groundbreaking discoveries, including active volcanoes on Jupiter’s moon Io, the intricate ring system of Saturn, and the mysterious atmosphere of Neptune. Voyager 2 remains the only spacecraft to have visited Uranus and Neptune, revealing surprising details about these distant planets and their moons.

After completing its planetary tour, Voyager 2 entered the Voyager Interstellar Mission (VIM) phase. This mission aimed to study the boundaries of our solar system, known as the heliosphere, and the space beyond. In 2018, Voyager 2 became the second spacecraft to leave the heliosphere and enter interstellar space, following Voyager 1’s milestone in 2012.

The plasma science instrument played a crucial role in detecting the heliopause, the boundary where the Sun’s influence ends, and interstellar space begins. As Voyager 2 crossed this threshold, the instrument measured a dramatic decrease in solar wind particles and an increase in cosmic rays from outside the solar system.

Table 1: Voyager 2’s Journey Milestones

Date	Milestone
1977	Launch of Voyager 2
1979	Flyby of Jupiter
1981	Flyby of Saturn
1986	Flyby of Uranus
1989	Flyby of Neptune
2018	Entry into interstellar space

Both Voyager spacecraft are powered by radioisotope thermoelectric generators (RTGs), which convert heat from decaying plutonium-238 into electricity. At the time of launch, each RTG provided 157 watts of electrical power, enough to keep Voyager 2 operational. However, the power output halves every 87.7 years, meaning the spacecraft’s available energy is steadily declining. NASA estimates that Voyager 2 loses about 4 watts of power each year, limiting its ability to run all onboard systems.

As power continues to dwindle, NASA engineers have been forced to make tough decisions about which instruments to prioritize. Over the past few years, they have turned off various non-essential systems, including heaters and voltage monitors, to conserve power for science instruments. The shutdown of the plasma science instrument is part of this broader effort to extend Voyager 2’s mission for as long as possible.

The Voyager mission is one of the most iconic in NASA’s history. Launched over 45 years ago, the twin spacecraft have traveled farther from Earth than any other human-made objects. Their discoveries have reshaped our understanding of the solar system, and their ongoing exploration of interstellar space continues to provide insights into a region of the universe that has never been studied before.

While Voyager 2 still has four operational instruments, its mission is entering its final phase. By the 2030s, the spacecraft will likely be down to just one or two working tools. However, even as its power supply diminishes, Voyager 2 will continue its journey through the cosmos, offering a unique glimpse into the mysteries of interstellar space.

NASA is already preparing for the inevitable end of the Voyager mission. When Voyager 2’s power finally runs out, the spacecraft will become a silent ambassador of Earth, carrying a golden record filled with sounds and images representing life on our planet. This record is intended to communicate with any intelligent beings that might encounter Voyager 2 in the distant future.

Voyager 2’s Scientific Contributions

Despite its aging systems, Voyager 2 remains an invaluable asset to space science. The data it continues to send back helps scientists understand phenomena such as the behavior of the interstellar medium and the interaction between the heliosphere and interstellar space. As the spacecraft travels farther from the Sun, its instruments provide a rare opportunity to study a region of space that has never been explored before.

Table 2: Voyager 2’s Operational Instruments

Instrument	Function
Magnetometer	Studies the interplanetary magnetic field
Charged Particle Instrument	Measures ions and electrons in space
Cosmic Ray System	Determines the origin of interstellar cosmic rays
Plasma Wave Detector	Detects plasma waves in the interstellar medium

The shutdown of Voyager 2’s plasma science instrument is a reminder that even the most ambitious space missions must eventually come to an end. Yet, despite this, Voyager 2 continues to push the boundaries of human exploration, sending back data from a region of space that no other spacecraft has reached. As it journeys farther into the unknown, Voyager 2 remains a testament to human curiosity, determination, and the enduring quest to understand our place in the universe.

References

#NASA, #Voyager2, #SpaceExploration, #InterstellarSpace, #Heliosphere, #PlasmaScience, #DeepSpace, #RTGs, #OuterPlanets, #GrandTour, #CosmicRays, #Heliopause, #Magnetometer, #CosmicExploration, #VoyagerProgram

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Space Exploration

When Will We Finally Lose Contact with Voyager?

By Simeon Bala July 19, 2024

When Will We Finally Lose Contact with Voyager?

Key Takeaways

Voyager 1: The furthest man-made object from Earth.
Voyager 2: Continues to operate with extended mission life.
Deep Space Network: Critical for maintaining communication with the Voyagers.
Power Sources: RTGs provide power, but it is depleting.
Golden Record: Contains information about Earth for any potential finders.
Final Contact: Communication expected to cease within the next few years.
Voyager 1’s Journey: Launched in 1977, traveled past Jupiter and Saturn, now in interstellar space.
Voyager 2’s Journey: Launched in 1977, traveled past Jupiter, Saturn, Uranus, Neptune, now in interstellar space.
Distance and Communication: Currently 24 billion kilometers away (Voyager 1) and over 20 billion kilometers away (Voyager 2), signals take about 22 hours each way.
Power Issues: Powered by RTGs, which are depleting.
Backup Power for Voyager 2: Extending mission life by using backup power.
Iconic Image: Pale Blue Dot taken in 1990, inspired by Carl Sagan.
Future Prospects: Will continue to drift through space, carrying the golden record.
Final Contact: Communication expected to cease within the next few years.

When Will We Finally Lose Contact with Voyager — Voyager 1 and Voyager 2 spacecraft in deep space field. 3D illustration

Introduction

Voyager 1, launched on September 5, 1977, is the furthest man-made object from Earth, currently about 24 billion kilometers away. It continues to speed into deep space, far beyond the influence of our solar system. Despite its distance, NASA recently revived Voyager 1 after it went silent, bringing all its systems back online. This raises an important question: how much longer can we maintain contact with Voyager 1 before it finally runs out of power?

Additionally, Voyager 2, launched in 1977 as well, is over 12 billion miles (20 billion kilometers) from Earth. With five science instruments studying interstellar space, Voyager 2 has begun using a small reservoir of backup power to keep its instruments operational, potentially extending its mission until 2026 and beyond.

The Journey of Voyager 1 and Voyager 2

Voyager 1

Voyager 1 was launched to explore the outer planets of our solar system. It provided humanity with some of the most stunning images and invaluable data from Jupiter and Saturn before embarking on an endless journey into interstellar space.

Key Milestones

1977: Launched from Earth.
1979: Reached Jupiter, capturing breathtaking images.
1980: Reached Saturn.
2012: Crossed the heliopause, entering interstellar space.

Voyager 2

Voyager 2, launched shortly before Voyager 1, has also made significant contributions to our understanding of the outer planets and interstellar space. It remains the only spacecraft to have visited Neptune and Uranus.

Key Milestones

1977: Launched from Earth.
1979: Reached Jupiter.
1981: Reached Saturn.
1986: Reached Uranus.
1989: Reached Neptune.
2018: Crossed the heliopause, entering interstellar space.

Understanding the Distance

To truly grasp the distance Voyager 1 and Voyager 2 have traveled, let’s consider the astronomical unit (AU), the distance between Earth and the Sun, roughly 150 million kilometers. Voyager 1 is now approximately 163 AU from Earth, more than four times the distance from the Sun to Pluto. Voyager 2, at over 20 billion kilometers, is similarly far, though not as distant as Voyager 1.

Distance and Communication

At its current distance, radio signals take 22 hours and 36 minutes to reach Voyager 1 and the same amount of time to return. Voyager 2, slightly closer, still requires significant time for signal transmission. This immense distance means that communication with these spacecraft is a significant achievement, maintained through NASA’s Deep Space Network.

The Deep Space Network

NASA’s Deep Space Network (DSN) consists of large radio antennas located in California, Australia, and Spain. These locations allow continuous communication with the Voyager spacecraft as the Earth rotates.

Transmitting Power: Voyager’s transmitter operates at just 20 watts, similar to a refrigerator light bulb.
Receiving Signals: The DSN’s massive 70-meter and 34-meter dishes can detect the faint signals sent from the Voyagers, capturing valuable data daily.

The Power Problem

Both Voyager spacecraft are powered by three radioisotope thermoelectric generators (RTGs), which convert heat from plutonium decay into electricity. However, as the plutonium decays over time, the power output gradually decreases.

Power Conservation Measures

To extend their operational lives, NASA engineers have turned off non-essential systems and instruments, including heaters and redundant scientific instruments. Despite these efforts, the power levels will eventually drop too low to support critical systems, leading to Voyager 1 and Voyager 2 going dark forever.

“Voyager 1 and Voyager 2 will continue their journeys through space, but their voices will eventually fade. Their missions, however, will remain testaments to human curiosity and ingenuity.”

Voyager 2’s Backup Power

Voyager 2 has begun using a small reservoir of backup power, set aside as part of an onboard safety mechanism. This move will enable the mission to postpone shutting down a science instrument until 2026, rather than this year.

Implications for Voyager 2

Switching off a science instrument will not end the mission. After shutting off the one instrument in 2026, the probe will continue to operate four science instruments until the declining power supply requires another to be turned off. If Voyager 2 remains healthy, the engineering team anticipates the mission could potentially continue for years to come.

The Iconic Pale Blue Dot

On February 14, 1990, Voyager 1 took one of the most famous images in space exploration history. As it was leaving our solar system, Carl Sagan convinced NASA to turn Voyager around to take a final image of Earth. This image, known as the “Pale Blue Dot,” shows Earth as a tiny speck in a vast expanse of space.

“That’s here. That’s home. That’s us.” — Carl Sagan

Future Prospects

As Voyager 1 and Voyager 2 continue their journeys, they will eventually pass through the Oort Cloud, a region of icy bodies surrounding our solar system. This journey will take thousands of years, and the Voyagers will drift through space, carrying with them the golden record, a time capsule containing information about Earth and humanity.

The Golden Record

The golden record includes:

Sounds: Greetings in 55 languages, natural sounds, and music.
Images: Pictures of people, animals, and nature.
Information: Details about Earth’s location and human knowledge.

The Final Contact

While it is difficult to predict the exact moment we will lose contact with Voyager 1 and Voyager 2, it is certain that this day is approaching. The power levels of their RTGs are expected to drop below critical levels within the next few years, leading to the cessation of all communications.

Table 1: Key Events in Voyager 1’s Journey

Year	Event
1977	Launch from Earth
1979	Reached Jupiter
1980	Reached Saturn
1990	Pale Blue Dot image
2012	Entered interstellar space
Future	Expected loss of communication

Table 2: Voyager 2’s Journey and Power Sources

Year	Event
1977	Launch from Earth
1979	Reached Jupiter
1981	Reached Saturn
1986	Reached Uranus
1989	Reached Neptune
2018	Entered interstellar space
Future	Backup power extends mission

Conclusion

Voyager 1 and Voyager 2’s journeys are remarkable achievements in human space exploration. As they travel further into deep space, they carry with them the story of humanity, etched in the golden record. Though we will eventually lose contact with these spacecraft, their missions will continue, silently drifting through the cosmos, beacons of our existence and symbols of our quest for knowledge.

“The Voyagers have shown us that the universe is vast and our home is a tiny speck in the grand scheme of things. Their journeys inspire us to explore, to dream, and to reach for the stars.”

References

NASA. (2024). Voyager 1.
NASA. (2024). Voyager 2.
Sagan, Carl. (1994). Pale Blue Dot: A Vision of the Human Future in Space. New York: Random House.
Oort Cloud. (2024). NASA Solar System Exploration.
Golden Record. (2024). NASA Voyager.

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#Voyager1, #Voyager2, #DeepSpace, #NASA, #SpaceExploration, #InterstellarSpace, #GoldenRecord, #PaleBlueDot, #SpaceMission, #RTGs

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Space Exploration

NASA’s Edward C. Stone, Voyager Visionary, Dies at 88

By Jonathan Bala June 14, 2024

NASA’s Edward C. Stone, Voyager Visionary, Dies at 88

Key Takeaways

Edward C. Stone, a luminary in space exploration and former director of NASA’s Jet Propulsion Laboratory, passed away on June 9, 2024, at age 88. Known for his leadership of the Voyager mission, Stone enhanced our understanding of the solar system and interstellar space. He also held a significant academic role at Caltech and received numerous accolades, including the National Medal of Science.

Stone served as the director of NASA’s Jet Propulsion Laboratory (JPL) from 1991 to 2001. He contributed to nine NASA missions as principal investigator or science instrument lead. Stone’s work on Voyager helped reveal significant discoveries about Jupiter, Saturn, Uranus, and Neptune. Under his leadership, Voyager 1 and Voyager 2 became the first human-made objects to enter interstellar space.He w as instrumental in engaging the public with scientific discoveries. Stone received numerous awards, including the National Medal of Science and the Shaw Prize in Astronomy.

Summary

Edward C. Stone, a prominent space scientist, died on June 9, 2024, at age 88.
He led the Voyager mission, NASA’s longest-running mission, which launched in 1977.
Stone’s leadership contributed to major discoveries about the outer planets and interstellar space.
He was the director of NASA’s Jet Propulsion Laboratory from 1991 to 2001.
Stone was involved in multiple NASA missions, including the Parker Solar Probe and Cassini.
He was a professor at Caltech and served as vice provost for special projects.
Stone received numerous accolades, including the National Medal of Science and the Shaw Prize in Astronomy.
He is survived by his two daughters, Susan and Janet, and two grandsons.
Stone was known for his ability to engage the public with scientific discoveries.

Remembering Edward C. Stone

Edward C. Stone, former director of NASA’s Jet Propulsion Laboratory (JPL) and longtime project scientist of the agency’s Voyager mission, died on June 9, 2024, at the age of 88. He was preceded in death by his wife, Alice Stone, whom he met at the University of Chicago. They are survived by their two daughters, Susan and Janet Stone, and two grandsons.

Early Life and Education

Edward Carroll Stone Jr. was born on January 23, 1936, in Knoxville, Iowa. The eldest of two sons of Edward Carroll Stone Sr. and Ferne Elizabeth Stone, he grew up in the nearby commercial center of Burlington. His father was a construction superintendent who delighted in showing his son how to take things apart and put them back together again. This early exposure to mechanics fostered Stone’s curiosity and passion for understanding the world around him.

After high school, Stone enrolled in Burlington Junior College to study physics and went on to the University of Chicago for graduate school. Shortly after he was accepted, the Soviet Union launched Sputnik, marking the beginning of the Space Age. Stone joined a team at the university that was building science instruments to launch into space.

Career Highlights

Stone is best known for his work on NASA’s longest-running mission, Voyager. The twin spacecraft launched in 1977 and are still exploring deep space today. He served as Voyager’s sole project scientist from 1972 until his retirement in 2022. Under Stone’s leadership, the mission took advantage of a celestial alignment that occurs just once every 176 years to visit Jupiter, Saturn, Uranus, and Neptune.

During their journeys, the spacecraft revealed significant discoveries, such as the first active volcanoes beyond Earth on Jupiter’s moon Io and an atmosphere rich with organic molecules on Saturn’s moon Titan. Voyager 2 remains the only spacecraft to fly by Uranus and Neptune, revealing Uranus’ unusual tipped magnetic poles and the icy geysers erupting from Neptune’s moon Triton.

Now more than 15 billion miles (24 million kilometers) from Earth, Voyager 1 is the most distant human-made object. Voyager 2, traveling slightly slower and in a different direction, is more than 12 billion miles (20 billion kilometers) from Earth. Both probes are exploring interstellar space, the region outside the heliosphere, which is a protective bubble created by the Sun’s magnetic field and the outward flow of charged particles.

“Becoming Voyager project scientist was the best decision I made in my life,” Stone said in 2018. “It opened a wonderful door of exploration.”

Ed Stone became project scientist for the Voyager mission in 1972. This was five years before launch. He served in the role for a total of 50 years. During that time, he also served as director of NASA’s Jet Propulsion Laboratory. This laboratory manages the Voyager mission for the agency. Credit: NASA/JPL-Caltech

Stone was particularly proud of the way Voyager quickened the pace of scientific analysis and took advantage of opportunities to engage the public. When Voyager 1 and 2 made their close flybys of the giant planets between 1979 and 1989, Stone was overseeing 11 teams of scientists, all accustomed to releasing their results at a slower pace through peer-reviewed journals.

Stone took the lead in tailoring the peer-review process to the faster pace of the mission’s planetary encounters. In the early afternoon, after data had come down, teams of scientists would decide what they thought their best results were for the day and hold up their conclusions for feedback in front of the whole science steering group. Based on that discussion, Stone would choose the most interesting results to present to the media and the public the next morning.

“It was a very exciting time, and everyone was making discoveries,” said Stamatios “Tom” Krimigis of the Johns Hopkins Applied Physics Laboratory. “Ed’s approach showed us how much public interest there really was in what Voyager was doing, but it also resulted in better science.”

Voyager’s high profile lifted Stone’s profile as well. In 1991, roughly two years after the mission completed its planetary flybys, Stone became director of JPL, serving until 2001. Under his leadership, JPL was responsible for more than two dozen missions and instruments. Highlights of Stone’s tenure included landing NASA’s Pathfinder mission with the first Mars rover, Sojourner, in 1996 and launching the NASA-ESA (European Space Agency) Cassini/Huygens mission in 1997.

Ed Stone, left, talks to reporters. This was at a news conference to announce findings from Voyager 2’s flyby of Uranus in 1986. Credit: NASA/JPL-Caltech

“Ed Stone was a leader who dared mighty things in space. He was a dear friend to all who knew him, and a cherished mentor to me personally,” said Nicola Fox, associate administrator for the Science Mission Directorate at NASA Headquarters in Washington. “Ed took humanity on a planetary tour of our solar system and beyond, sending NASA where no spacecraft had gone before.”

Scientific Contributions

Stone served on nine NASA missions as either principal investigator or a science instrument lead and on five others as a co-investigator. These roles primarily involved studying energetic ions from the Sun and cosmic rays from the galaxy. He had the distinction of being one of the few scientists involved with both the mission that has come closest to the Sun (NASA’s Parker Solar Probe) and the one that has traveled farthest from it (Voyager).

“Ed will be remembered as an energetic leader and scientist who expanded our knowledge about the universe — from the Sun to the planets to distant stars — and sparked our collective imaginations about the mysteries and wonders of deep space,” said Laurie Leshin, JPL director and Caltech vice president. “Ed’s discoveries have fueled exploration of previously unseen corners of our solar system and will inspire future generations to reach new frontiers.”

Achievements and Awards

Among Stone’s many awards, the National Medal of Science from President George H.W. Bush stands out as the most prominent. In 2019 he won the Shaw Prize in Astronomy, with an award of $1.2 million, for his leadership in the Voyager project. As the citation noted, the project “has over the past four decades, transformed our understanding of the four giant planets and the outer solar system, and has now begun to explore interstellar space.”

He was also proud to have a middle school named after him in Burlington, Iowa, as an inspiration to young learners. Stone’s contributions have left an indelible mark on the scientific community and beyond.

Ed Stone, second from left, and other members of the Voyager team pose with a model of the spacecraft in 1977, the year the twin probes launched. Credit: NASA/JPL-Caltech

Legacy

Edward C. Stone’s legacy is a testament to the power of curiosity, perseverance, and the human spirit’s quest for knowledge. His work has inspired countless scientists and space enthusiasts, shaping our understanding of the universe and pushing the boundaries of exploration.

“Thank you, Ed, for everything,” said Nicola Fox. “Your legacy has left a tremendous and profound impact on NASA, the scientific community, and the world.”

Tables of Achievements and Missions

Table 1: Key Achievements of Edward C. Stone

Year	Achievement
1972	Became Voyager Project Scientist
1977	Voyager 1 and 2 launched
1989	Completion of Voyager planetary flybys
1991-2001	Director of NASA’s Jet Propulsion Laboratory
1996	Landing of Mars Pathfinder mission
1997	Launch of Cassini/Huygens mission
2001	Stepped down as JPL Director
2012	Voyager 1 entered interstellar space
2019	Awarded Shaw Prize in Astronomy
2022	Retired from Voyager Project Scientist role

Table 2: NASA Missions Involving Edward C. Stone

Mission	Role	Key Contributions
Voyager 1 and 2	Project Scientist	First active volcanoes on Io, atmosphere on Titan
Parker Solar Probe	Science Instrument Lead	Study of the Sun’s energetic particles
Cassini/Huygens	Director of JPL	Saturn orbiter, probe landing on Titan
Mars Pathfinder	Director of JPL	First Mars rover, Sojourner
Spitzer Space Telescope	Director of JPL	Infrared astronomy
Various satellite missions	Principal Investigator	Study of galactic cosmic rays and solar particles

Conclusion

Edward C. Stone’s life and career were marked by a relentless pursuit of knowledge and an unwavering dedication to space exploration. His leadership of the Voyager mission, his role as director of NASA’s Jet Propulsion Laboratory, and his numerous contributions to our understanding of the solar system and beyond have left an enduring legacy. Stone’s work not only advanced scientific discovery but also inspired the public and future generations of scientists to look to the stars.

His achievements remind us of the vast potential of human ingenuity and the importance of exploring the unknown. As we remember Edward C. Stone, we celebrate a visionary whose impact on space exploration will be felt for generations to come.

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