Reprinted by NASA.
30 years ago, on August 25, 1989, NASA's Voyager 2 spacecraft made a close flight to Neptune, giving humanity its first close-up on the eighth planet of our solar system. To mark the end of the Grand voyage of the Voyager mission on the four giant planets of the solar system – Jupiter, Saturn, Uranus and Neptune – this was the first and the last: since then no other spacecraft has visited Neptune. Ed Stone, a professor of physics at Caltech and a scientist on the Voyager project since 1975, says:
The Voyager planetary program was really an opportunity to show the public what science is all about. Every day we learn something new.
Enveloped in clouds of tulle and cobalt, the planet Voyager 2 revealed looked like Sibby's son with Jubiter and Saturn, with blue indicating the presence of methane. A large, shale-colored storm was called the Big Dark Spot, much like Jupiter's Big Red Spot. Six new moons and four rings have been discovered.
During the meeting, the engineering team carefully changed the direction and speed of the probe so that it could make a close flight of the largest moon on the planet – Triton. The pilot showed evidence of young geological surfaces and active geysers pushing material toward the sky. This shows that Triton is not just a solid ball of ice, although it has the lowest surface temperature of any natural body observed by Voyager: minus 391 degrees Fahrenheit (minus 235 degrees Celsius).
The conclusion of the Neptune fly marks the beginning of the Voyager Interstellar Mission, which continues today, 42 years after launch. Voyager 2 and its twin, Voyager 1 (which also flew Jupiter and Saturn) continue to send back shipments from the outer reaches of our solar system. During the meeting with Neptune, Voyager 2 was located about 2.9 billion miles (4.7 billion km) from Earth; today it is 11 billion miles (18 billion km) from us. The faster moving Voyager 1 is 13 billion miles (21 billion km) from Earth.
How to get there
By the time Voyager 2 reaches Neptune, Voyager's mission team has completed five planetary meetings. But the big blue planet still posed unique challenges.
About 30 times farther from the sun than Earth, the ice giant receives only about 0.001 times the amount of sunlight the Earth makes. In such low light, the Voyager 2's camera requires longer exposures to get quality images. But since the spacecraft will reach a top speed of about 60,000 km / h compared to 90,000 km / h relative to Earth, long exposure times will make the image blurry. (Imagine trying to take a picture of a sidewalk from a speed-window.)
So the team programs the Voyager 2 sidewalks to shoot slightly at close range, rotating the spacecraft to keep the camera focused on its target, without interrupting the overall speed and direction of the spacecraft.
The great probe distance also meant that by the time the Voyager 2 radio signals reached Earth, they were weaker than those of other flywheels. But the spacecraft had the advantage of time: Voyagers communicate with Earth through the deep space network or DSN, which uses radio antennas at sites in Madrid, Spain; Canberra, Australia; and Goldstone, California. During the Uranium 2 meeting of Uranus in 1986, the three largest DSN antennas were 64 meters (210 feet) wide. To support the meeting with Neptune, the DSN expanded the plates to 70 meters (230 feet). They also include nearby antennas without a DSN for data acquisition, including another 64-meter (210-ft) antenna in Parks, Australia, and multiple 25-meter antennas in the very large array in New Mexico.
The efforts ensured that engineers could hear Voyager loud and clear. In addition, the amount of data that can be sent back to Earth over a given period is increased, allowing the spacecraft to send back more images of the flight.
During the week leading up to the August 1989 meeting, the atmosphere was electric at the NASA Jet Propulsion Laboratory in Pasadena, California, which runs the Voyager mission. As the images taken by Voyager 2 during his approach to Neptune made the four-hour journey to Earth, Voyager team members would huddle around computer monitors around the Lab. Stone said:
One of the things that made Voyager's planetary meetings different from missions today is that there is no internet that allows the entire team and the world to see the photos at the same time. Images were available in real time in a limited number of locations.
But the team is committed to providing the public with updates as quickly as possible, so that from August 21 to 29, they will share their findings with the world during daily press conferences. On August 24, a program called Voyager All Night broadcasts regular updates from the closest probe meeting with the planet, which took place at 4 a.m. GMT (9:00 pm in California on August 24).
The next morning, Vice President Dan Quayle visited the lab to give praise to the Voyager team. That evening, Chuck Berry, whose song Johnny B. Goodwood was included in the Golden Record, which flew with the two Voyagers, plays at the JPL's feast.
Of course, Voyagers' accomplishments are well beyond the historic week of three decades ago. Both probes have already entered the interstellar space after leaving the heliosphere – a protective bubble around the planets created by a high-speed stream of particles and magnetic fields pushed out of our sun.
They report back to Earth for the "weather" and conditions from that region, filled with debris from stars that erupted elsewhere in our galaxy. They have made humanity's first vital step in the space ocean, where no other exploration probes have flown.
Voyager data also complements other missions, including NASA's Interstellar Boundary Explorer (IBEX), which remotely senses this boundary where particles of our sun collide. with material from the rest of the galaxy. And NASA is preparing an Interstellar Mapping and Acceleration Probe (IMAP), which is scheduled to launch in 2024 to benefit from Voyager observations.
Voyagers send their findings back to DSN antennas with 13-watt transmitters – about enough power to start a light bulb. Stone says:
Every day they travel somewhere that human probes have never been. Forty-two years after launch and they're still exploring.
For more information on the Voyager mission, visit https://voyager.jpl.nasa.gov/ records19659006 ImagesFor more photos of Neptune taken from a visit to Voyager 2 https://voyager.jpl.nasa.gov/galleries/images -voyager-took / neptune / records19659033 SAMSA Big Blue Crescent Neptune, to Triton Miniature Blue Crescent. "width =" 800 "height =" 572 "class =" size-full wp-image-204904 "/>
Bottom line: It's been 30 years since Voyager 2 visits Neptune as part of Voyager's Grand Tour of the Four Giant Planets of the Solar System To date, no other Earth spaceship has returned to Neptune.
Read more: Mission Information Sheet by Voyager