An international team of scientists is planning a mission to interplanetary space that will take 50 years to complete. It will become a multi-generational project.
A team at Johns Hopkins University Applied Physics Laboratory, which flew the New Horizons probe to Pluto in 2015, is collaborating with the European Sciences Union to design a mission called Interstellar Probe that will reach out beyond the heliosphere of the sun.
The heliosphere is a cosmic bubble that surrounds our entire solar system, where the outward flow of charged particles blown off the sun, known as the solar wind, meets the interstellar environment of our Milky Way galaxy.
To reach that region, the spacecraft will need to fly 1,000 astronomical units (AU) or 1,000 times farther away from the sun than the Earth. That's about 150 billion kilometres from here, a journey that will take half a century to complete.
Such a mission would be launched some time in the 2030s, which means some of the scientists planning the mission today will not be alive when it reaches its destination.
Voyager spacecraft working their way out
The only other spacecraft to report from interstellar space are the Voyager 1 and 2 spacecraft. Launched in 1977, the twin robotic probes flew by Jupiter and Saturn, with Voyager 2 continuing on to Uranus and Neptune.
Each of the big planets gave the probes a gravity assist, which accelerated them up to a speed high enough to escape the gravity of the sun and wander among the stars of our galaxy for billions of years. Only five spacecraft have accomplished that, Pioneer 10 and 11, which preceded the Voyagers, and New Horizons, which is now beyond Pluto.
Voyager 1 is now the most distant object sent from Earth at just over 150 AU. The Interstellar Probe will go more than six times farther out.
Probing the outer reaches of our solar system
The heliosphere is our protective shield against cosmic rays from the galaxy. It also changes with time, shimmering like a giant soap bubble as activity on the sun fluctuates, and as the nature of the interstellar medium changes. While the Voyagers defined the outer limits of the heliosphere, the Interstellar Probe will take a broader approach and study its behaviour.
Another way to look at it is studying the sun in its full cosmic context as it travels around the Milky Way.
This proposal demonstrates not only long term thinking, something that's often rare in today's world, but also how long it takes for even our fastest spacecraft to get out of our solar system.
As a journalist covering the Voyager mission from launch over the 12 years it took to reach Neptune, I watched myself, colleagues and scientists get older as the mission proceeded. Hair turned from black to grey, or fell out, our typewriters evolved into laptops, some people even died before the end.
Space is really, really big.
Plan from the past reaching into the future
Planning a mission that will be completed by future generations is wonderful foresight in science.
The planners of the Voyager mission knew from the beginning that the spacecraft would go interstellar, but they were only given funding to explore Jupiter and Saturn. Still, the engineers made sure the spacecraft had fuel tanks for the manoeuvring thrusters that were large enough to go the distance and a nuclear power supply that could last 50 years. They were then able to get extra funding to continue the exploration after the spacecraft were on their way.
This week on you will hear about American botanist Prof. William Beal, who, in 1879, started a long term experiment by filling 20 jars with an assortment of seeds and buried them underground to see how long they could remain dormant. The idea was to unearth a jar periodically to see which seeds would germinate.
That project is still going on today and thanks to new technology, questions can be asked about those seeds that were not possible in Beal's time.
Science often looks into the past through ancient artifacts and fossils. Looking to the future is more difficult but also exciting because we don't know what that future will bring.
The Interstellar Probe will be humanity casting a line as far out into the ocean of spaces we can reach.
It will be up to future generations to find out what we catch.
ABOUT THE AUTHOR
Bob McDonald is the host of CBC Radio's award-winning weekly science program, Quirks & Quarks. He is also a science commentator for CBC News Network and CBC-TV's The National. He has received 12 honorary degrees and is an Officer of the Order of Canada.
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