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50 Years of Engineering - 1977: Launch of Voyager 1 & 2

25/02/2020
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To celebrate Fircroft’s 50th anniversary, EngineeringPro is celebrating the engineering accomplishments made from 1970-2020. Each week we look back at a different year and a particular engineering marvel that changed the world. This week we’re revisiting 1977 and the launch of a project that took human exploration to new realms and continues to deliver new discoveries from beyond our solar system today: the Voyager Program.

Two identical space probes were launched on the Voyager program - each is still in operation, flying further away from Earth and beyond our solar system
(Image via NASA)

“If you want to do space experiments, you have to be optimistic that it’s all going to work and that you’re going to find something worth the work. And you have to be patient, because nothing happens fast in space.” - Professor Ed Stone, Voyager Chief Scientist, speaking in March 2015.

Jupiter's Great Red Spot, photographed by Voyager 1 as it flew past the giant gas planet
(Image via NASA)

Though the project was initially devised around the same time as the Apollo missions, the Voyager program didn’t have its first launch until 8 years after Neil Armstrong first set foot on the moon. Planned to take advantage of an optimal alignment of the planets Jupiter, Saturn, Uranus and Neptune: two robotic probes were launched to gather close up data for the first time on our planet’s gigantic neighbours. 

The Voyager probes initially formed part of the Mariner program - a 10 mission NASA program that hoped to investigate Mars, Venus and Mercury. As the scope for the program expanded, it was eventually split off into the separate “Mariner Jupiter-Saturn” program, later renamed “Voyager”. 

NASA engineer's constructing the antenna dish for one of the Voyager probes
(Image via NASA)

The plan was for two probes following a similar path to another - ultimately cancelled - program named the “Planetary Grand Tour”. Jet Propulsion Laboratory Aerospace engineer Gary Flandro had discovered a particular alignment of the outer planets that would allow a craft to use gravitational assists to fly past each giant world. The alignment occurs just once every 175 years, offering - in Flandro’s words - “the chance of three lifetimes”.

Voyager 2 being lifted into the launch vehicle
(Image via NASA)

Voyager 2 was launched on 20th August 1977, followed 16 days later on 5th September by its twin craft, Voyager 1.

Despite the launch order, Voyager 1 would be the first to reach Jupiter and Saturn, due to a planned trajectory that was shorter and less circular. Voyager 1’s mission was for a close flyby of Jupiter and Saturn, while Voyager 2 would pass the planets from a slightly further distance and follow its own trajectory to Uranus and Neptune.

The Voyager 1 space probe
(Image via NASA)

The probes are identical. Each is roughly the size of a transit van and weighs 772kg, containing scientific instruments, radio systems and a power source. Nuclear power was devised as the most suitable source of electricity, since the probes would be travelling too far from the Sun for solar power to be effective. Radioisotope Thermoelectric Generators would convert heat from decaying plutonium-238 into electricity to power the probes.

Each probe holds 11 analytic instruments designed to examine atmospheric chemistry, detect magnetic fields, detect aurorae, measure charged particles, determine physical properties of the planets through radio signals and detect solar wind through plasma measurements.

A gold record featuring sounds and images of Earth was sent aboard each Voyager craft
(Image via NASA)

They each also carry a gold plated LP record with a needle and cartridge and instructions for playing. Within its grooves the record contains 115 photos from Earth; a selection of “sounds of Earth” including sounds like whale songs, a baby crying, waves breaking on a shore; a collection of music from around the world including pieces by Mozart, Valya Balkanska and Chuck Berry; and spoken greetings from esteemed people such as the Secretary-General of the United Nations and the President of the United States. The idea for the record came from famed planetary scientist Carl Sagan, whose young son Nick recorded one additional message for the record:

“Hello from the children of planet Earth.” 

Jupiter and its moons, as photographed by Voyager
(Image via NASA)

Journey to the edge of the Solar System

15 months after launch, in January 1979, Voyager 1 reached the planet Jupiter, followed a few months later by Voyager 2. At its closest, Voyager 1 was just 349,000km (217,000 miles) from the planet’s centre. Iconic photos of the planet’s Great Red Spot were sent back to Earth, along with revolutionary data on its magnetosphere and never-before-seen planetary rings. One of the biggest discoveries was the surprising find of volcanic activity from Jupiter’s moon, Io. The craft then moved on to make similarly radical discoveries of Saturn, and return close-up images of the ringed planet. 

Saturn, photographed by Voyager 1
(Image via NASA)

Passing Jupiter and Saturn at a greater distance than its twin, Voyager 2 carried on to become the first man-made object to reach Uranus (making its closest approach of 81,500km (50,600 miles) of the planets cloudtops on 24th January 1986) and Neptune (closest approach on 25th August 1989).

Uranus, as photographed by Voyager 2
(Image via NASA)

Once the planetary mission of each craft was over, they continued their journey into deep space. During the 1990s Voyager 1 overtook the slower-moving deep-space probes Pioneer 10 and Pioneer 11 to become the most distant human-made object from Earth. 

On 25th August 2012, Voyager 1 crossed the heliopause, marking the boundary at the edge of the reach of the Sun’s solar winds and the entry point to interstellar space. Voyager 2 crossed the boundary on the 5th November 2018.

Interstellar diagram showing Voyager 1 & 2 leaving the Heliopause
(Image via NASA)

Beyond a lifetime

The Voyager probes were only intended for their planetary mission, yet they continue to operate today.

“The robustness is unique,” said Suzy Dodd, Project Manager, Voyager Interstellar Mission to The Guardian in 2015. 

“If you talk to the older engineers, they’ll say: ‘Well, we were told to make a four-year mission, but we realised if you just used this higher-rated component, it would last twice as long.’ So they did that. They just didn’t tell anybody. The early engineers were very conscious of trying to make this last as long as possible and, quite frankly, being not as forthcoming with information about the types of parts they were using.”

Despite continuously running for so long in the -235C temperature of outer space, the probes still send data to operators on Earth. The on-board computers were extremely advanced upon launch, but can’t compete with everyday devices in the present day - an iPhone computer, for example, is around 200,000 times faster than the Voyager processor and contains around 250,000 times more memory.

Timeline and system map of the Voyager program
(Image via NASA)

But the power source will not last forever. On Valentines day 1990, Voyager 1’s on-board camera was turned around to point back at Earth for one last photo before being deactivated to save power. The photo shows the planet Earth, home of everything mankind has ever known in its history, as a “pale blue dot”, smaller than one pixel, alone in the vastness of space. 

Taken from around 6 billion km (3.7 billion miles) from the Earth, the photo has become one of the most iconic astronomical images. 

“Look again at that dot. That’s here. That’s home. That’s us. On it everyone you love, everyone you know, everyone you have ever heard of, every human being who ever was, lived out their lives. The aggregate of our joy and suffering, thousands of confident religions, ideologies, and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilization, every king and peasant, every young couple in love, every mother and father, hopeful child, inventor and explorer, every teacher of morals, every corrupt politician, every “superstar”, every “supreme leader” every saint and sinner in the history of our species lived there - on a mote of dust suspended in a sunbeam.” - Carl Sagan

The Pale Blue Dot photo - reprocessed by NASA engineers in 2019
(Image via NASA)

From this year, the remaining scientific instruments on each craft are due to be deactivated one by one, with the final instruments to be shut down by 2025. After that time, the only signals received from the Voyager crafts will be a periodic, faint electronic blip indicating the position of the probes as they continue their journey beyond the Solar System until the decaying power supply finally runs out.

The Voyager program - originally planned as a 4 year journey - will run for almost half a century. In that time the two probes have taught us vast amounts about our neighbouring planets and much more about what lies beyond, allowing scientists to form new theories about dark matter, the birth of stars and the origins of life. 

Neptune, photographed by Voyager 2
(Image via NASA)

“Billions of years from now our sun, then a distended red giant star, will have reduced Earth to a charred cinder. But the Voyager record will still be largely intact, in some other remote region of the Milky Way galaxy, preserving a murmur of an ancient civilization that once flourished - perhaps before moving on to greater deeds and other worlds - on the distant planet Earth.” - Carl Sagan

The engineering world of 1977

The trans-Alaska pipeline began production in 1977
(Image via Luca Galuzzi)

Other major engineering milestones from 1977 include:

  • The Commodore PET, the world’s first all-in-one home computer is demonstrated at Chicago’s Consumer Electronics Show in January. It would go on sale the following September.
  • Apple Computer is incorporated on the 3rd January and the Apple II goes on sale on the 5th June.
    The Space Shuttle Enterprise has its first test flight, mated to the Boeing 747 Shuttle Carrier Aircraft on the 18th February. It would make its first test free-flight on the 12th August.
  • The Trans-Alaska Pipeline System is completed, with first oil transported from Prudhoe Bay to Valdez, Alaska in July. Full scale production is reached by the end of the year.
  • Electrically conducting organic polymers are discovered by researchers Hideki Shirakawa, Alan MacDiarmid and Alan Heeger, who would be awarded the Nobel Prize in chemistry in 2000. The polymers are developed into light-emitting diodes LEDS), solar cells and mobile telephone displays.

Read our look back at 1976 and the introduction into commercial service of the world’s most successful supersonic passenger jet: Concorde.

Fircroft: 50 years of connecting people

Fircroft was founded in 1970 and has been recruiting engineering and technical professionals for major innovative projects for the last half-century. Register with us today to find out how our 50 years of experience can help you secure your next engineering job.

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50 Years of Engineering - 1977: Launch of Voyager 1 & 2 - Time to read 9 min
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