Voyager 2 spacecraft launched 49 years ago today

John Casani was the Voyager project manager in 1977. Here he is holding a small flag that was folded and sewn into the thermal blankets of the Voyager 2 spacecraft before launch. Voyager 2 is behind him, and the famous golden record the Voyagers carried is in front. Read about the story of the record here.

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Voyager 2 launched 49 years ago

NASA launched the phenomenal Voyager 2 space probe to the outer solar system on August 20, 1977. Voyager 2 went up some weeks before its twin craft, Voyager 1, which moved faster and eventually passed it.

Later, Voyager 1 became the first spacecraft to leave the solar system in August 2012. It is now the most distant human-made object from Earth. In fact, on November 18, 2026, Voyager 1 spacecraft will be 16,094,799,096 miles (25,902,068,356 kilometers) away from Earth. That’s the distance light travels in 24 hours, also known as one light-day.

Voyager 2 left the solar system in November 2018. So both Voyagers are now in interstellar space. Voyager 2 was left flying solo for seven months in 2020 while repairs were made to the radio antenna that commands it. The only radio antenna that can command the space probe – the Deep Space Station 43 (DSS43) antenna in Canberra, Australia – was then offline during the repairs. After the completion of the repairs, communications were restored.

Today, transmissions from Voyager 2 are faint and travel a long distance. But the craft still transmits and receives data via NASA’s Deep Space Network. Scientists believe it will be able to continue communications through 2027.

Where are Voyager 1 and 2 now?

As Voyager 2 sped away from Earth, it looked back and acquired this image of a crescent-shaped Earth and moon – the first of its kind ever taken by a spacecraft – on September 18, 1977. Voyager 2 was then 7.3 million miles (11.7 million kilometers) from Earth. Image via NASA.

Voyager 2 is the only spacecraft to visit all 4 gas giant planets

A region of Jupiter’s southern hemisphere extending from the Great Red Spot to the south pole. Before the Voyagers, we did not know Jupiter’s banded atmosphere, or Red Spot, contained so much detail. Image via NASA/ JPL/ CalTech.

Before the Voyagers, we did not know that Saturn’s rings consisted of thousands of individual ringlets. In this Voyager 2 image from 1981, you can also see the mysterious “spokes” in Saturn’s rings. Image via NASA.

Voyager 2 is still the only spacecraft to have visited the outer planets Uranus and Neptune. Here is Uranus as seen by Voyager 2 in 1986. To the spacecraft, the planet appeared as a featureless blue ball. Image via NASA.

Voyager 2 passed Neptune in 1989. It saw cloud features in Neptune’s atmosphere, which were tracked by Voyager’s cameras as the craft swept past. Image via NASA.

NASA Voyager photo gallery

The Grand Tour was a phenomenal success

Initially, NASA conceived of the Voyager mission in the 1960s as a planetary Grand Tour to study the outer planets. The fact that all four outer planets would be, temporarily, within one quadrant of the solar system around the decade of the 1980s inspired the idea. However, funding difficulties intervened, and for a time it appeared the Grand Tour would never be realized.

Ultimately, Voyager 2’s launch took advantage not only of this particular configuration of planets, but also of a new technique called a gravity assist. By using the gravity of planets for propulsion and direction, this technique let the craft visit all four outer planets (Jupiter, Saturn, Uranus and Neptune), while requiring a minimal amount of propellant and less time traveling between planets.

The plan hinged on whether Voyager 1 would be able to perform a successful flyby of Saturn’s large and intriguing moon Titan. Of course Voyager 1 succeeded, and Voyager 2 got the go-ahead to travel on toward Uranus and Neptune, ultimately realizing the vision of the planetary Grand Tour.

Voyager 2 remains the only craft from Earth to have visited Uranus and Neptune.

Bottom line: The phenomenal Voyager 2 spacecraft launched on August 20, 1977. It ultimately visited all four outer planets – Jupiter, Saturn, Uranus and Neptune – and remains the only craft from Earth to have done so.

JPL/ NASA Voyager website

Read more: Voyager 2 sends back insights on interstellar space

The post Voyager 2 spacecraft launched 49 years ago today first appeared on EarthSky.

from EarthSky https://ift.tt/hiwnzKE

John Casani was the Voyager project manager in 1977. Here he is holding a small flag that was folded and sewn into the thermal blankets of the Voyager 2 spacecraft before launch. Voyager 2 is behind him, and the famous golden record the Voyagers carried is in front. Read about the story of the record here.

Science news, night sky events and beautiful photos, all in one place. Click here to subscribe to our free daily newsletter.

Voyager 2 launched 49 years ago

NASA launched the phenomenal Voyager 2 space probe to the outer solar system on August 20, 1977. Voyager 2 went up some weeks before its twin craft, Voyager 1, which moved faster and eventually passed it.

Later, Voyager 1 became the first spacecraft to leave the solar system in August 2012. It is now the most distant human-made object from Earth. In fact, on November 18, 2026, Voyager 1 spacecraft will be 16,094,799,096 miles (25,902,068,356 kilometers) away from Earth. That’s the distance light travels in 24 hours, also known as one light-day.

Voyager 2 left the solar system in November 2018. So both Voyagers are now in interstellar space. Voyager 2 was left flying solo for seven months in 2020 while repairs were made to the radio antenna that commands it. The only radio antenna that can command the space probe – the Deep Space Station 43 (DSS43) antenna in Canberra, Australia – was then offline during the repairs. After the completion of the repairs, communications were restored.

Today, transmissions from Voyager 2 are faint and travel a long distance. But the craft still transmits and receives data via NASA’s Deep Space Network. Scientists believe it will be able to continue communications through 2027.

Where are Voyager 1 and 2 now?

As Voyager 2 sped away from Earth, it looked back and acquired this image of a crescent-shaped Earth and moon – the first of its kind ever taken by a spacecraft – on September 18, 1977. Voyager 2 was then 7.3 million miles (11.7 million kilometers) from Earth. Image via NASA.

Voyager 2 is the only spacecraft to visit all 4 gas giant planets

A region of Jupiter’s southern hemisphere extending from the Great Red Spot to the south pole. Before the Voyagers, we did not know Jupiter’s banded atmosphere, or Red Spot, contained so much detail. Image via NASA/ JPL/ CalTech.

Before the Voyagers, we did not know that Saturn’s rings consisted of thousands of individual ringlets. In this Voyager 2 image from 1981, you can also see the mysterious “spokes” in Saturn’s rings. Image via NASA.

Voyager 2 is still the only spacecraft to have visited the outer planets Uranus and Neptune. Here is Uranus as seen by Voyager 2 in 1986. To the spacecraft, the planet appeared as a featureless blue ball. Image via NASA.

Voyager 2 passed Neptune in 1989. It saw cloud features in Neptune’s atmosphere, which were tracked by Voyager’s cameras as the craft swept past. Image via NASA.

NASA Voyager photo gallery

The Grand Tour was a phenomenal success

Initially, NASA conceived of the Voyager mission in the 1960s as a planetary Grand Tour to study the outer planets. The fact that all four outer planets would be, temporarily, within one quadrant of the solar system around the decade of the 1980s inspired the idea. However, funding difficulties intervened, and for a time it appeared the Grand Tour would never be realized.

Ultimately, Voyager 2’s launch took advantage not only of this particular configuration of planets, but also of a new technique called a gravity assist. By using the gravity of planets for propulsion and direction, this technique let the craft visit all four outer planets (Jupiter, Saturn, Uranus and Neptune), while requiring a minimal amount of propellant and less time traveling between planets.

The plan hinged on whether Voyager 1 would be able to perform a successful flyby of Saturn’s large and intriguing moon Titan. Of course Voyager 1 succeeded, and Voyager 2 got the go-ahead to travel on toward Uranus and Neptune, ultimately realizing the vision of the planetary Grand Tour.

Voyager 2 remains the only craft from Earth to have visited Uranus and Neptune.

Bottom line: The phenomenal Voyager 2 spacecraft launched on August 20, 1977. It ultimately visited all four outer planets – Jupiter, Saturn, Uranus and Neptune – and remains the only craft from Earth to have done so.

JPL/ NASA Voyager website

Read more: Voyager 2 sends back insights on interstellar space

The post Voyager 2 spacecraft launched 49 years ago today first appeared on EarthSky.

from EarthSky https://ift.tt/hiwnzKE