In 1958, the National Aeronautics and Space Act founded the National Aeronautics and Space Administration (NASA). Its founding came at an opportune time, and not just because of the Space Race against the Soviets. An astrological phenomenon would take place in the next 20 years, and it was an event that took place once every 176 years. Interestingly, this phenomenon was only discovered years after the creation of NASA.
In January 1958, months before the creation of NASA, the Army Ballistic Missile Agency (ABMA) launched the first American-made satellite into orbit. The satellite, called Explorer 1, was designed, built, and operated by California-based Jet Propulsion Laboratory (JPL), and it went 1,563 miles. More Explorer satellites were launched in 1958, prior to the creation of NASA, and, even after its creation, JPL remained a vital partner in space exploration.
A Surprising Discovery
In 1965, while NASA conducted its Gemini missions of launching astronauts into space, Gary Flandro, a graduate student at Caltech and part-time aeronautics researcher at JPL, was making mathematical calculations of how to reach the planets—Jupiter, Saturn, Uranus and Neptune—located on the outer reaches of the solar system.
Flandro realized that flybys of these major planets could be done by the use of “gravity assist.” Gravity assist, which was observed by late-18th- and early-19th-century astronomers studying the flight paths of asteroids, allows an object to use a planet’s gravitational pull to accelerate its propulsion like a slingshot. If NASA could launch a satellite in time, it could utilize gravity assist to go from planet to planet and possibly even to interstellar space—the space outside of the heliosphere.
“There was scant interest in the outer planets,” Flandro said, “mainly because of their great distances and long times-of-flight (Jupiter 3-5 years, Saturn 10-12 years, Uranus 20-28 years, Neptune 30-45 years) required for robotic exploration. At that time, it had proved difficult to build reliable spacecraft that could survive more than a year or two in the space environment.”
Pioneer and Mariner Jupiter/Saturn
Pioneer 10 finally came to fruition on March 2, 1972, when the 569-pound, nuclear-powered satellite began its mission to become the first robotic spacecraft to escape the solar system and reach interstellar space. It was the first spacecraft to pass Mars, fly through the main asteroid belt, pass Jupiter, and then Neptune, which it accomplished in less than 12 years. The reason the satellite was able to reach and surpass Neptune so quickly was because it was also the first spacecraft to utilize “gravity assist” when it used Jupiter’s gravitational pull. Additionally, this spacecraft, which was designed for a 21-month mission, lasted more than 30 years with its last signal being sent on Jan. 23, 2003, from 7.6 billion miles away.Preparing the Voyagers
NASA was provided $865 million (approximately $6.5 billion today) to accomplish the MJS mission. By the time the spacecraft for the MJS ‘77 was complete, there were two nuclear-powered spacecraft, each approximately three times the size in mass of the Pioneer 10 and 11. In March 1977, the MJS ’77 mission name was changed to Voyager, and the two spacecraft were renamed to reflect the change: Voyager 1 and Voyager 2. the MSJ 77 mission name was changed...”
The objective of Voyager 2, which was planned to launch first, was to conduct flybys of Jupiter and Saturn, but also Uranus and Neptune, before continuing on into interstellar space. Voyager 1, which was placed on a shorter trajectory to interstellar space and would therefore overtake Voyager 2 (which is why it was called Voyager 1), was commissioned to conduct flybys of Jupiter and Saturn before exiting the solar system.
Voyagers Launch
On Aug. 20, 1977, Voyager 2 launched from Cape Canaveral, followed by Voyager 1 on Sept. 5. This probing expedition came with very high expectations. Considering that these spacecraft, which were flying at speeds exceeding 38,000 miles per hour, would be touring uncharted areas of the solar system, the scientists weren’t certain what to expect. In the years to come, the discoveries would be groundbreaking.Along with collecting “magnetic, atmospheric, lunar, and other data,” the Voyagers encountered Jupiter and its moons Amalthea, Callisto, Europa, Ganymede, and Io (with its previously unknown active volcanoes); and discovered two new moons, Metis and Thebes. A faint ring around Jupiter was discovered, and major atmospheric changes were identified (something Pioneer 10 and 11 did not indicate. They discovered five new moons around Saturn and provided new information about the planet’s ring.
It was from Saturn that the Voyager 1 and 2 went in two completely different directions. Voyager 2 pressed on toward Uranus and Neptune. At Uranus, it discovered 10 new moons, which were all given Shakespearean names. On Aug. 25, 1989, after covering 4.3 billion miles, Voyager 2 arrived at Neptune, where it discovered six new moons and four new rings. It captured images of Neptune’s largest moon, Triton—”the coldest known planetary body in the solar system.” After 12 years, the Voyager 2 had officially accomplished the “Grand Tour” of the outer reaches. After approximately 35 million miles outside of the solar system, NASA placed the spacecraft on “low-power mode to conserve energy.”
It was now time to pursue interstellar space, resulting in NASA changing the project name to Voyager Interstellar Mission.
‘The Family Portrait’
Of those images, one taken by Voyager 1 has, arguably, become the most famous.The Voyager Imaging Team, which chose the Vidicon cameras and were thus in charge of the visuals of the project, were composed of several leading astronomical voices. One of those voices had become famous for his many TV appearances and his Peabody Award-winning PBS series “Cosmos.” Carl Sagan was the most famous person on the Team and when the Voyager 1 had completed its flyby of Neptune, he made a consequential request. He wanted the spacecraft to take a “family portrait.”
It took three hours for the spacecraft’s Vidicon camera to warm up, and by this time it was nearly 4 billion miles from the sun. It was during this week in history, on Feb. 14, 1990, that Voyager 1 took photos of Neptune, Uranus, Saturn, Venus, Earth, and Jupiter. It would take approximately two months for these images to be sent to earth via the Deep Space Network. When the images were produced, one came out exactly as Sagan had anticipated: a “pale blue dot.”
The image of Earth from billions of miles away became world-renowned due to Sagan. He often exhibited the photo during his talks, and, in 1994, he published a book called “Pale Blue Dot.”
In his book, he wrote, “It has been said that astronomy is a humbling and character-building experience. There is perhaps no better demonstration of the folly of human conceits than this distant image of our tiny world. To me, it underscores our responsibility to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we’ve ever known.”
Over the following 35 years, Voyagers 1 and 2 traversed billions of miles further from Earth, making the planet an even smaller, if not invisible, “speck.” Both spacecraft are now further than any man-made object has ever gone, zooming through interstellar space (Pioneer 10 is in interstellar space and Pioneer 11 should reach interstellar space in 2027).
It remains to be seen how far into space Voyagers 1 and 2 will last and for how long they will remain in communication with Earth. Regardless, what was accomplished in 1977 by NASA and JPL remains awe-inspiring, especially considering the accomplishment was made by relatively few people working together on a “pale blue dot.”
