Writer: Josue Navarro ‘25
Editor: Lorenzo Mahoney ‘24
(Left: Voyage 1, Right: Voyager 2)
Are we alone in the universe? This question has intrigued astronomers and space explorers for centuries. In the 17th century, Galileo began experimenting with lenses to view very distant objects up close (2). He mastered the art of creating the first telescopes to provide a glimpse of what happens in our solar system. He discovered that four moons revolve around Jupiter and was puzzled by the appearance of Saturn–later found to have rings around it (2). Since then, the scientific revolution took off, and scientists have used the latest technologies at their disposal to further explore our solar system and beyond.
Space exploration in the United States began with the founding of NASA in October of 1958 (3). After flybys and landings of new unmanned spacecraft on the rocky planets (Mercury, Venus, and Mars), NASA was ready for more. The agency's Voyager mission was created to explore Jupiter and Saturn to understand their composition, atmosphere, and the satellites that orbit them (4). In the summer of 1977, two spacecraft, Voyager 1 and Voyager 2, were launched into space by NASA with the purpose of exploring the gas giants through extensive high resolution imaging during fly-by missions that would last for 4-5 years (4). Voyager 1 arrived at Jupiter on March 5, 1979, and at Saturn on November 12, 1980. It studied Titan (Saturn’s largest moon) and Saturn’s rings, providing information on Saturn’s ring structure and Titan’s dense atmosphere made of rock and water ice (4). Voyager 2 flew by Jupiter on July 9, 1979, and Saturn on August 25, 1981. It provided stunning new photographs of both of the planets as they passed by (5).
Image 3. Jupiter and Two Moons (6). Image 4. Saturn and Three Moons
Tethys. Dion and Rhea.
Voyager 1, (August 4, 1982) (6).
Following initial successes, the Voyager Mission was extended to all four gas giants (Jupiter, Saturn, Uranus, and Neptune) because the spacecraft were deemed likely to make it to Uranus and Neptune with all instruments operating (4). Renamed the Voyager Interstellar Neptune Mission, Voyager 2 encountered Uranus on January 24, 1986 and Neptune on August 25, 1989. Voyager 2 returned detailed photos of Uranus, and information about the planet and its moons. When it flew by Neptune, it discovered six new moons, a nitrogen ice volcano, and four new rings, which were completely unknown to scientists before the voyager missions (5). Voyager 1 traveled even further from Earth, without flying-by Uranus and Neptune (7). On February 14, 1990, Voyager 1’s camera was pointed back to Earth to take its last pictures of Earth and our solar system (7). These images were dubbed the “Pale Blue Dot,” with Earth just a speck of dust in the distance (7). From there, Voyager 1’s cameras were shut off as it headed towards interstellar space to conserve energy (8). After Voyager 2’s Neptune encounter was completed, it headed toward interstellar space, and the mission was renamed to the Voyager Interstellar Mission (7).
“The Pale Blue Dot”
Voyager 1 (February 14, 1990) (9).
In May 1993, scientists found that the spacecraft was picking up radio emissions that originated at the heliopause (4). The heliopause is the outer edge of the solar system, where solar winds no longer pass through. The heliopause is a distance of 90-120 astronomical units from the sun (one astronomical unit is about 93 million miles). In 1998, the scan platform was turned off on Voyager 2, while Voyager 1’s scan platform was left on to investigate UV emissions (4).
In August 2012, Voyager 1 became the first spacecraft to cross into interstellar space, and in December 2018, Voyager 2 became the second (5, 7). With both spacecraft officially outside our solar system, traveling at 11 miles per second, NASA has worked hard to keep up communication between the Voyagers and Earth. However, the generators that are supplying power to the spacecraft (which work using a limited radioactive isotope) are running out of energy. These spacecraft are estimated to be in communication with Earth until 2025-2026, after which they will no longer have enough power to send any information back to Earth. When this happens, they will continue to float in space for eternity, unless something or someone stops it.
How will we know if these spacecraft encounter forms of intelligent life in the future? The truth is, we won’t. However, the spacecraft has golden records that contain pictures and sounds from Earth, instructions on how to play the record, and a description of where we are in the universe. And though these spacecraft are expected to go silent within the next 10 years, they have changed our understanding of the universe, and maybe, someday somewhere, they will change the understanding of other beings in the furthest confines of the universe as well.
References
Space (Ukrainian Astrophysicists Group), Voyager 1 and Voyager 2 [Illustration]. 2023. Medium.
Telescopic Discoveries of Galileo [Internet]. Encyclopædia Britannica, inc.; [cited 2023 Oct 29]. Available from: https://www.britannica.com/biography/Galileo-Galilei/Telescopic-discoveries
Barry B, Garber S. Chronology of Defining Events in NASA History [Internet]. NASA History Division; 2012 [cited 2023 Oct 29]. Available from: https://history.nasa.gov/40thann/define.htm
California Institute of Technology. The Voyager Planetary Mission [Internet]. Jet Proportion Laboratory; [cited 2023 Oct 29]. Available from: https://voyager.jpl.nasa.gov/frequently-asked-questions/fact-sheet/#:~:text=The%20Voyager%20Planetary%20Mission,moons%20of%20the%20two%20planets
Uri J. 40 Years Ago: Voyager 1 Explores Saturn [Internet]. Johnson Space Center; 2023 [cited 2023 Oct 29]. Available from: https://www.nasa.gov/history/40-years-ago-voyager-1-explores-saturn/#:~:text=Voyager%201%20measured%20Titan%27s%20diameter,and%20began%20its%20outbound%20journey
NASA Jet Proportion Laboratory, Jupiter and its Moons, Saturn and Three Moons. 1982. California Institute of Technology. NASA Voyager.
Bolles D. Voyager 2 [Internet]. NASA; 2023 [cited 2023 Oct 29]. Available from: https://science.nasa.gov/mission/voyager-2/
Bolles D. Voyager 1 [Internet]. NASA; 2023 [cited 2023 Oct 29]. Available from: https://science.nasa.gov/mission/voyager-1/
NASA Jet Proportion Laboratory, The Pale Blue Dot. 1990. California Institute of Technology. NASA Voyager.
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