Friday August 20, 2021’s Smile of the Day: Voyager 2

On this Day:

In 1977, NASA launched Voyager 2 towards Jupiter, Saturn, Uranus and Neptune.

Voyager 2 is a space probe launched by NASA on August 20, 1977, to study the outer planets and interstellar space beyond the Sun’s heliosphere. A part of the Voyager program, it was launched 16 days before its twin, Voyager 1, on a trajectory that took longer to reach Jupiter and Saturn but enabled further encounters with Uranus and Neptune. It is the only spacecraft to have visited either of these two ice giant planets. Voyager 2 was the fourth of five spacecraft to achieve the Solar escape velocity, which allowed it to leave the Solar System.

Voyager 2 successfully fulfilled its primary mission of visiting the Jovian system in 1979, the Saturnian system in 1981, Uranian system in 1986, and the Neptunian system in 1989. Voyager 2 is now in its extended mission of studying Interstellar Space and has been operating for 43 years, 11 months and 28 days as of May 28, 2021, reaching a distance of 126.9 AU (19.0 billion km; 11.8 billion mi) from Earth.

The probe crossed into interstellar space on November 5, 2018, at a distance of 122 AU (1.83×1010 km) (about 16:58 light-hours) from the Sun and moving at a velocity of 15.341 km/s (55,230 km/h) relative to the star. Voyager 2 left the Sun’s heliosphere and entered the interstellar medium (ISM), a region of outer space beyond the influence of the Solar System, joining Voyager 1 which had reached the interstellar medium in 2012. Voyager 2 has begun to provide the first direct measurements of the density and temperature of the interstellar plasma.

Voyager 2 remains in contact with Earth through the NASA Deep Space Network. In 2020, maintenance to the Deep Space Network cut outbound contact with the probe for eight months. Contact was reestablished on November 2, 2020, when a series of instructions was transmitted, subsequently executed, and relayed back with a successful communication message. As of February 12, 2021, full communications with the probe were restored after a major antenna upgrade that took a year to complete. The DSS 43 communication antenna, solely responsible for communications with the probe, is located near Canberra, Australia.

In the early space age, it was realized that a periodic alignment of the outer planets would occur in the late 1970s and enable a single probe to visit Jupiter, Saturn, Uranus, and Neptune by taking advantage of the then-new technique of gravity assists. NASA began work on a Grand Tour, which evolved into a massive project involving two groups of two probes each, with one group visiting Jupiter, Saturn, and Pluto and the other Jupiter, Uranus, and Neptune. The spacecraft would be designed with redundant systems to ensure survival through the entire tour. By 1972 the mission was scaled back and replaced with two Mariner program-derived spacecraft, the Mariner Jupiter-Saturn probes. To keep apparent lifetime program costs low, the mission would include only flybys of Jupiter and Saturn, but keep the Grand Tour option open.[4]:263 As the program progressed, the name was changed to Voyager.

The primary mission of Voyager 1 was to explore Jupiter, Saturn, and Saturn’s moon, Titan. Voyager 2 was also to explore Jupiter and Saturn, but on a trajectory that would have the option of continuing on to Uranus and Neptune, or being redirected to Titan as a backup for Voyager 1. Upon successful completion of Voyager 1’s objectives, Voyager 2 would get a mission extension to send the probe on towards Uranus and Neptune.

Constructed by the Jet Propulsion Laboratory (JPL), Voyager 2 included 16 hydrazine thrusters, three-axis stabilization, gyroscopes and celestial referencing instruments (Sun sensor/Canopus Star Tracker) to maintain pointing of the high-gain antenna toward Earth. Collectively these instruments are part of the Attitude and Articulation Control Subsystem (AACS) along with redundant units of most instruments and 8 backup thrusters. The spacecraft also included 11 scientific instruments to study celestial objects as it traveled through space.

Built with the intent for eventual interstellar travel, Voyager 2 included a large, 3.7 m (12 ft) parabolic, high-gain antenna (see diagram) to transceive data via the Deep Space Network on the Earth. Communications are conducted over the S-band (about 13 cm wavelength) and X-band (about 3.6 cm wavelength) providing data rates as high as 115.2 kilobits per second at the distance of Jupiter, and then ever-decreasing as the distance increased, because of the inverse-square law. When the spacecraft is unable to communicate with Earth, the Digital Tape Recorder (DTR) can record about 64 megabytes of data for transmission at another time.

Voyager 2 is equipped with 3 Multihundred-Watt radioisotope thermoelectric generators (MHW RTG). Each RTG includes 24 pressed plutonium oxide spheres, and provides enough heat to generate approximately 157 W of electrical power at launch. Collectively, the RTGs supplied the spacecraft with 470 watts at launch (halving every 87.7 years). They were predicted to allow operations to continue until at least 2020 and have already done so.

Because of the energy required to achieve a Jupiter trajectory boost with an 1,819-pound (825 kg) payload, the spacecraft included a propulsion module made of a 2,476-pound (1,125 kg) solid-rocket motor and eight hydrazine monopropellant rocket engines, four providing pitch and yaw attitude control, and four for roll control. The propulsion module was jettisoned shortly after the successful Jupiter burn.

Sixteen hydrazine MR-103 thrusters on the mission module provide attitude control. Four are used to execute trajectory correction maneuvers; the others in two redundant six-thruster branches, to stabilize the spacecraft on its three axes. Only one branch of attitude control thrusters is needed at any time.

Thrusters are supplied by a single 28-inch (70 cm) diameter spherical titanium tank. It contained 230 pounds (100 kg) of hydrazine at launch, providing enough fuel until 2034.

It was originally thought that Voyager 2 would enter interstellar space in early 2016, with its plasma spectrometer providing the first direct measurements of the density and temperature of the interstellar plasma. In December 2018, the Voyager project scientist, Edward C. Stone, announced that Voyager 2 reached interstellar space on November 5, 2018.

Voyager 2 is not headed toward any particular star, although in roughly 42,000 years it will pass 1.7 light-years from the star Ross 248. And if undisturbed for 296,000 years, Voyager 2 should pass by the star Sirius at a distance of 4.3 light-years. Voyager 2 is expected to keep transmitting weak radio messages until at least the mid 2020s, more than 48 years after it was launched.

Each Voyager space probe carries a gold-plated audio-visual disc in the event that either spacecraft is ever found by intelligent life-forms from other planetary systems. The discs carry photos of the Earth and its lifeforms, a range of scientific information, spoken greetings from the people (e.g. the Secretary-General of the United Nations and the President of the United States, and the children of the Planet Earth) and a medley, “Sounds of Earth”, that includes the sounds of whales, a baby crying, waves breaking on a shore, and a collection of music, including works by Wolfgang Amadeus Mozart, Blind Willie Johnson, Chuck Berry’s “Johnny B. Goode”, Valya Balkanska and other Eastern and Western classics and ethnic performers (per Wikipedia).

First, a Story:

The US Government received the bill from NASA for sending the Voyager 1 and 2 probes into space and they were shocked to see that it was nearly 3 billion dollars.

They phoned the head of NASA and explained that they thought NASA wouldn’t be charging to send these probes into space.

The head of NASA responded by saying, ‘there’s no such thing as a free launch’

Second, a Song:

The Voyager Golden Records are two phonograph records that were included aboard both Voyager spacecraft launched in 1977. The records contain sounds and images selected to portray the diversity of life and culture on Earth, and are intended for any intelligent extraterrestrial life form who may find them. The records are a sort of time capsule.

Although neither Voyager spacecraft is heading toward any particular star, Voyager 1 will pass within 1.6 light-years’ distance of the star Gliese 445, currently in the constellation Camelopardalis, in about 40,000 years.

Carl Sagan noted that “The spacecraft will be encountered and the record played only if there are advanced space-faring civilizations in interstellar space, but the launching of this ‘bottle’ into the cosmic ‘ocean’ says something very hopeful about life on this planet.”

The contents of the record were selected for NASA by a committee chaired by Carl Sagan of Cornell University. The selection of content for the record took almost a year. Sagan and his associates assembled 115 images and a variety of natural sounds, such as those made by surf, wind, thunder and animals (including the songs of birds and whales). To this they added audio content to represent humanity: spoken greetings in 55 ancient and modern languages, including a spoken greeting in English by U.N. Secretary-General Kurt Waldheim and a greeting by Sagan’s six-year-old son, Nick; other human sounds, like footsteps and laughter (Sagan’s); the inspirational message Per aspera ad astra in Morse code; and musical selections from different cultures and eras. The record also includes a printed message from U.S. president Jimmy Carter.

The collection of images includes many photographs and diagrams both in black and white, and color. The first images are of scientific interest, showing mathematical and physical quantities, the Solar System and its planets, DNA, and human anatomy and reproduction. Care was taken to include not only pictures of humanity, but also some of animals, insects, plants and landscapes. Images of humanity depict a broad range of cultures. These images show food, architecture, and humans in portraits as well as going about their day-to-day lives. Many pictures are annotated with one or more indications of scales of time, size, or mass. Some images contain indications of chemical composition. All measures used on the pictures are defined in the first few images using physical references that are likely to be consistent anywhere in the universe.

The musical selection is also varied, featuring works by composers such as J.S. Bach (interpreted by Glenn Gould), Mozart, Beethoven (played by the Budapest String Quartet), and Stravinsky. The disc also includes music by Guan Pinghu, Blind Willie Johnson, Chuck Berry, Kesarbai Kerkar, Valya Balkanska, and electronic composer Laurie Spiegel, as well as Azerbaijani folk music (Mugham) by oboe player Kamil Jalilov. The inclusion of Berry’s “Johnny B. Goode” was controversial, with some claiming that rock music was “adolescent”, to which Sagan replied, “There are a lot of adolescents on the planet.” The selection of music for the record was completed by a team composed of Carl Sagan as project director, Linda Salzman Sagan, Frank Drake, Alan Lomax, Ann Druyan as creative director, artist Jon Lomberg, ethnomusicologist Robert E. Brown, Timothy Ferris as producer, and Jimmy Iovine as sound engineer. It also included the sounds of humpbacked whales from the 1970 album by Roger Payne, Songs of the Humpback Whale.

The Golden Record also carries an hour-long recording of the brainwaves of Ann Druyan. During the recording of the brainwaves, Druyan thought of many topics, including Earth’s history, civilizations and the problems they face, and what it was like to fall in love.

After NASA had received criticism over the nudity on the Pioneer plaque (line drawings of a naked man and woman), the agency chose not to allow Sagan and his colleagues to include a photograph of a nude man and woman on the record. Instead, only a silhouette of the couple was included. However, the record does contain “Diagram of vertebrate evolution”, by Jon Lomberg, with drawings of an anatomically correct naked male and naked female, showing external organs. The person waving on the diagram was also changed: on the Pioneer plaque, the man is waving, while on the “Vertebrate evolution” image, the woman is waving.

The pulsar map and hydrogen molecule diagram are shared in common with the Pioneer plaque.

The 115 images are encoded in analogue form and composed of 512 vertical lines. The remainder of the record is audio, designed to be played at 16+2⁄3 revolutions per minute.

Jimmy Iovine, who was still early in his career as a music producer, served as sound engineer for the project at the recommendation of John Lennon, who was contacted to contribute but was unable to take part.

Sagan’s team wanted to include the Beatles song “Here Comes the Sun” on the record, but the record company EMI, which held the copyrights, declined. In the 1978 book Murmurs of Earth, the failure to secure permission for the song is cited as one of the legal challenges faced by the team compiling the Voyager Golden Record. In the book, Sagan said that the Beatles favoured the idea, but “[they] did not own the copyright, and the legal status of the piece seemed too murky to risk.” When asked about the obstacle presented by EMI with regard to “Here Comes the Sun”, despite the artists’ wishes, Ann Druyan said in 2015: “Yeah, that was one of those cases of having to see the tragedy of our planet. Here’s a chance to send a piece of music into the distant future and distant time, and to give it this kind of immortality, and they’re worried about money … we got this telegram [from EMI] saying that it will be $50,000 per record for two records, and the entire Voyager record cost $18,000 to produce.” However, this was denied in 2017 by Timothy Ferris; in his recollection, “Here Comes the Sun” was never considered for inclusion.

In July 2015, NASA uploaded the audio contents of the record to the audio streaming service SoundCloud.

“Johnny B. Goode” is a 1958 rock-and-roll song written and first recorded by Chuck Berry. The song was a major hit, peaking at number two on Billboard magazine’s Hot R&B Sides chart and number eight on its Hot 100 chart.

“Johnny B. Goode” is considered one of the most recognizable songs in the history of popular music. Credited as “the first rock & roll hit about rock & roll stardom”, it has been recorded by many other artists and has received several honors and accolades, including being ranked seventh on Rolling Stone’s list of the “500 Greatest Songs of All Time” and included as one of the 27 songs on the Voyager Golden Record, a collection of music, images, and sounds designed to serve as a record of humanity.

A cover version of Johnny B. Goode is included in the film Back to the Future, when the lead character Marty McFly plays it at a high school dance. Actor Michael J. Fox explained his approach to “incorporate all the characteristics and mannerisms and quirks of my favourite guitarists, so a Pete Townshend windmill, and Jimi Hendrix behind the back, and a Chuck Berry duckwalk. And we worked all that in.” Reviewer Gregory Wakeman described it as “one of the best musical performances in movie history” (per Wikipedia).

The complete track listing for the Voyager Golden Record can be found on the right hand side of the listing.  Johnny B. Goode is the 13th track in this version.  I hope you enjoy this!


Thought for the Day:

“In spite of the opinions of certain narrow-minded people, who would shut up the human race upon this globe, as within some magic circle it must never outstep, we shall one day travel to the moon, the planets, and the stars, with the same facility, rapidity, and certainty as we now make the voyage from Liverpool to New York!” – Jules Verne

Have a great day!

Dave & Colleen

© 2021 David J. Bilinsky and Colleen E. Bilinsky

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