== The Voyager Program

The Voyager program is an American scientific program under the aegis of ((NASA)) that employs two Interstellar probes,(((Voyager Program,Voyager 1)))Voyager 1 and (((Voyager Program,Voyager 2))) Voyager 2. They were launched in 1977 to take advantage of a favorable planetary alignment to explore the two gas giants (((Gas Giants,Jupiter))) Jupiter and (((Gas Giants,Saturn))) Saturn and potentially also the ice giants, (((Ice Giants,Uranus))) Uranus and (((Ice Giants,Neptune))) Neptune - to fly near them while collecting data for transmission back to Earth. After Voyager 1 successfully completed its flyby of Saturn and its moon indexterm:[Gas Giants,Saturn,Titan] Titan
it was decided to send Voyager 2 on flybys of Uranus and Neptune. Voyager 2 also obtained high-resolution pictures of Saturn's indexterm:[Gas Giants,Saturn,Rings] rings on Aug. 22 1981.

indexterm:[Interstellar Medium]
After the planetary flybys were complete, decisions were made to keep the probes in operation to explore interstellar space and the outer regions of the solar system. On 25 August 2012, data from (((Voyager Program,Voyager 1)))Voyager 1 indicated that it had entered interstellar space. On 5 November 2019, data from (((Voyager Program,Voyager 2)))Voyager 2 indicated that it also had entered interstellar space.On 4 November 2019, scientists reported that on 5 November 2018, the (((Voyager Program,Voyager 1)))Voyager 2 probe had officially reached the Interstellar Medium,ISM interstellar medium (ISM), a region of outer space beyond the influence of the solar wind, as did (((Voyager Program,Voyager 1)))Voyager 1 in 2012. In August 2018, NASA confirmed, based on results by the ((New Horizons)) spacecraft, the existence of a "((Hydrogen Wall))" at the outer edges of the Solar System that was first detected in 1992 by the two Voyager spacecraft.
 
The two Voyager space probes were originally conceived as part of the Planetary Grand Tour planned during the late 1960s and early 70s that aimed to explore Jupiter, Saturn, Saturn's moon, Titan, Uranus, Neptune, and ((Pluto)). The mission originated from the Grand Tour program, conceptualized by ((Gary Flandro)), an aerospace engineer at the ((Jet Propulsion Laboratory)), in 1964, which leveraged a rare planetary alignment occurring once every 175 years.This alignment allowed a craft to reach all outer planets using ((Gravitational Assists))gravitational assists. The mission was to send several pairs of probes and gained momentum in 1966 when it was endorsed by NASA's Jet Propulsion Laboratory. However, in December 1971, the Grand Tour mission was canceled when funding was redirected to the ((Space Shuttle)) program.

The probes would be launched in August or September 1977, with their main objective being to compare the characteristics of Jupiter and Saturn, such as their atmospheres, magnetic fields, particle environments, ring systems, and moons. They would fly by planets and moons in either a JST or JSX trajectory. After completing their flybys, the probes would communicate with Earth, relaying vital data using their magnetometers, spectrometers, and other instruments to detect interstellar, solar, and cosmic radiation. Their ((radioisotope thermoelectric generators)) (RTGs) would limit the maximum communication time with the probes to roughly a decade. Following their primary missions, the probes would continue to drift into interstellar space.

(((Voyager Program,Voyager 2)))Voyager 2 was the first to be launched. Its trajectory was designed to allow flybys of Jupiter, Saturn, Uranus, and Neptune. (((Voyager Program,Voyager 1)))Voyager 1 was launched after (((Voyager Program,Voyager 2)))Voyager 2, but along a shorter and faster trajectory that was designed to provide an optimal flyby of Saturn's moon Titan, which was known to be quite large and to possess a dense atmosphere. This encounter sent (((Voyager Program,Voyager 1)))Voyager 1 out of the plane of the ecliptic, ending its planetary science mission. Had (((Voyager Program,Voyager 1)))Voyager 1 been unable to perform the Titan flyby, the trajectory of (((Voyager Program,Voyager 2)))Voyager 2 could have been altered to explore Titan, forgoing any visit to Uranus and Neptune. (((Voyager Program,Voyager 1)))Voyager 1 was not launched on a trajectory that would have allowed it to continue to Uranus and Neptune, but could have continued from Saturn to Pluto without exploring Titan.

During the 1990s, (((Voyager Program,Voyager 1)))Voyager 1 overtook the slower deep-space probes Pioneer 10 and Pioneer 11 to become the most distant human-made object from Earth, a record that it will keep for the foreseeable future. The New Horizons probe, which had a higher launch velocity than (((Voyager Program,Voyager 1)))Voyager 1, is traveling more slowly due to the extra speed (((Voyager Program,Voyager 1)))Voyager 1 gained from its flybys of Jupiter and Saturn. (((Voyager Program,Voyager 1)))Voyager 1 and Pioneer 10 are the most widely separated human-made objects anywhere since they are traveling in roughly opposite directions from the Solar System.

In December 2004, (((Voyager Program,Voyager 1)))Voyager 1 crossed the termination shock, where the solar wind is slowed to subsonic speed, and entered the ((Heliosheath))heliosheath, where the solar wind is compressed and made turbulent due to interactions with the interstellar medium. On 10 December 2007, (((Voyager Program,Voyager 2)))Voyager 2 also reached the termination shock, about 1.6 billion kilometres (1 billion miles) closer to the Sun than from where (((Voyager Program,Voyager 1)))Voyager 1 first crossed it, indicating that the ((Solar System)) is asymmetrical.

In 2010 (((Voyager Program,Voyager 1)))Voyager 1 reported that the outward velocity of the solar wind had dropped to zero, and scientists predicted it was nearing interstellar space. In 2011, data from the Voyagers determined that the heliosheath is not smooth, but filled with giant magnetic bubbles, theorized to form when the magnetic field of the Sun becomes warped at the edge of the Solar System.

In June 2012, Scientists at NASA reported that (((Voyager Program,Voyager 1)))Voyager 1 was very close to entering interstellar space, indicated by a sharp rise in high-energy particles from outside the Solar System. In September 2013, NASA announced that (((Voyager Program,Voyager 1)))Voyager 1 had crossed the heliopause on 25 August 2012, making it the first spacecraft to enter interstellar space. Uranus

In December 2018, NASA announced that (((Voyager Program,Voyager 2)))Voyager 2 had crossed the heliopause on 5 November 2018, making it the second spacecraft to enter interstellar space.

As of 2017 (((Voyager Program,Voyager 1)))Voyager 1 and (((Voyager Program,Voyager 2)))Voyager 2 continue to monitor conditions in the outer expanses of the Solar System. The Voyager spacecraft are expected to be able to operate science instruments through 2020, when limited power will require instruments to be deactivated one by one. Sometime around 2025, there will no longer be sufficient power to operate any science instruments. The Hydrogen Wall was a big discovery. 


After the planetary flybys were complete, decisions were made to keep the probes in operation to explore interstellar space and the outer regions of the solar system. On 25 August 2012, data from (((Voyager Program,Voyager 1)))Voyager 1 indicated that it had entered interstellar space. On 5 November 2019, data from (((Voyager Program,Voyager 2)))Voyager 2 indicated that it also had entered interstellar space.On 4 November 2019, scientists reported that on 5 November 2018, the (((Voyager Program,Voyager 2)))Voyager 2 probe had officially reached the Interstellar Medium,ISM interstellar medium (ISM), a region of outer space beyond the influence of the solar wind, as did (((Voyager Program,Voyager 1)))Voyager 1 in 2012. In August 2018, indexterm:[NASA]NASA confirmed, based on results by the ((New Horizons)) spacecraft, the existence of a "((Hydrogen Wall))" at the outer edges of the Solar System that was first detected in 1992 by the two Voyager spacecraft.
indexterm:[NASA]
indexterm:[Discoveries,Hydrogen Wall]
indexterm:[Interstellar Medium]
indexterm:[Solar Wind]
After the planetary flybys were complete, decisions were made to keep the probes in operation to explore interstellar space and the outer regions of the solar system. On 25 August 2012, data from (((Voyager Program,Voyager 1)))Voyager 1 indicated that it had entered interstellar space. On 5 November 2019, data from (((Voyager Program,Voyager 2)))Voyager 2 indicated that it also had entered interstellar space.On 4 November 2019, scientists reported that on 5 November 2018, the (((Voyager Program,Voyager 2)))Voyager 2 probe had officially reached the Interstellar Medium,ISM interstellar medium (ISM), a region of outer space beyond the influence of the solar wind, as did (((Voyager Program,Voyager 1)))Voyager 1 in 2012. In August 2018, NASA confirmed, based on results by the ((New Horizons)) spacecraft, the existence of a "((Hydrogen Wall))" at the outer edges of the Solar System that was first detected in 1992 by the two Voyager spacecraft.
After the planetary flybys were complete, decisions were made to keep the probes in operation to explore interstellar space and the outer regions of the solar system. On 25 August 2012, data from (((Voyager Program,Voyager 1)))Voyager 1 indicated that it had entered interstellar space. On 5 November 2019, data from (((Voyager Program,Voyager 2)))Voyager 2 indicated that it also had entered interstellar space.On 4 November 2019, scientists reported that on 5 November 2018, the (((Voyager Program,Voyager 2)))Voyager 2 probe had officially reached the Interstellar Medium,ISM interstellar medium (ISM), a region of outer space beyond the influence of the solar wind, as did (((Voyager Program,Voyager 1)))Voyager 1 in 2012. In August 2018, NASA confirmed, based on results by the ((New Horizons)) spacecraft, the existence of a "((Hydrogen Wall))" at the outer edges of the Solar System that was first detected in 1992 by the two Voyager spacecraft.
After the planetary flybys were complete, decisions were made to keep the probes in operation to explore interstellar space and the outer regions of the solar system. On 25 August 2012, data from (((Voyager Program,Voyager 1)))Voyager 1 indicated that it had entered interstellar space. On 5 November 2019, data from (((Voyager Program,Voyager 2)))Voyager 2 indicated that it also had entered interstellar space.On 4 November 2019, scientists reported that on 5 November 2018, the (((Voyager Program,Voyager 2)))Voyager 2 probe had officially reached the Interstellar Medium,ISM interstellar medium (ISM), a region of outer space beyond the influence of the solar wind, as did (((Voyager Program,Voyager 1)))Voyager 1 in 2012. In August 2018, NASA confirmed, based on results by the ((New Horizons)) spacecraft, the existence of a "((Hydrogen Wall))" at the outer edges of the Solar System that was first detected in 1992 by the two Voyager spacecraft.
After the planetary flybys were complete, decisions were made to keep the probes in operation to explore interstellar space and the outer regions of the solar system. On 25 August 2012, data from (((Voyager Program,Voyager 1)))Voyager 1 indicated that it had entered interstellar space. On 5 November 2019, data from (((Voyager Program,Voyager 2)))Voyager 2 indicated that it also had entered interstellar space.On 4 November 2019, scientists reported that on 5 November 2018, the (((Voyager Program,Voyager 2)))Voyager 2 probe had officially reached the Interstellar Medium,ISM interstellar medium (ISM), a region of outer space beyond the influence of the solar wind, as did (((Voyager Program,Voyager 1)))Voyager 1 in 2012. In August 2018, NASA confirmed, based on results by the ((New Horizons)) spacecraft, the existence of a "((Hydrogen Wall))" at the outer edges of the Solar System that was first detected in 1992 by the two Voyager spacecraft.(((Voyager Program,Voyager 2)))Voyager 2 obtained this high-resolution picture of Saturn's (((Gas Giants,Saturn,Rings)))rings Aug. 22 1981.
