Fastest Ever Space Probe Would Travel Into Interstellar Space To Explore Our Solar System From Outside In

Humans have created precisely one object that has arguably escaped the bounds of our solar system, Voyager 1. That spacecraft took 35 years to make it that far and it has only left our neighborhood as an afterthought, wandering on aimlessly after completing its true mission: to swing by Jupiter and Saturn.

Now, scientists are dreaming of accomplishing the feat again, this time with a spacecraft expressly built for the purpose. An interstellar probe would tackle questions that we simply can’t answer from within the comfort of our own solar system.  We would need to be in it for the long haul: scientists are asking what we could do with a launch scheduled for between 2050 and 2070. But the scientists asking what it would take and what we could do with such a mission say it would be worth the forethought.

“It will truly be a historical mission to take our first step into interstellar space,” Pontus Brandt, a space physicist at Johns Hopkins University’s Applied Physics Laboratory in Maryland, told Newsweek. “The ultimate dream here is to reach out into interstellar space and eventually, at some point in the future, to reach another star.” He and a group of colleagues presented their preliminary analysis of what an interstellar probe mission could do at the Triennial Earth-Sun Summit conference held this week in Virginia.

It’s not a new idea; scientists have dreamed of touching the edge of our solar system for more than five decades. But technologically, it’s only just now becoming practical to plan missions that would need to eventually hit speeds of about 20 astronomical units, the distance between the sun and Earth, per year, or about 200,000 miles per hour. Voyager 1 is currently clocking less than a fifth of that speed.

Read more: Potentially Habitable Europa Has Plumes That Could Reshape Hunt for Alien Life

While the star destination would be the space just past our solar system’s border, they’d consider a pit stop or two along the way. Brandt cites the New Horizons mission’s flyby of Pluto in 2015, which he says came at a time when people weren’t all that interested in the tiny former planet and its neighbors. “Those four hours of that flyby completely changed the notion of what the Kuiper Belt objects really are,” he said, referring to the region of icy dwarf planets and planetary rubble that rings our solar system beyond Neptune’s orbit.

Brandt suggests a Kuiper Belt object called Quaoar would make an intriguing target. It may sport volcanoes powered by liquid water rather than liquid rock, plus it seems to have lost track of the methane that made up its atmosphere. They also think a mission’s timeline could work out perfectly so that Quaoar is conveniently located along the way to the nose of our solar system, where our neighborhood is plowing through the space that surrounds it.

(Within our solar system, the spacecraft could also visit the hypothesized Planet 9 if it turns out to exist.)

And once the probe passes the edge of our solar system, there’s plenty for it to look back at. Ironically, when it comes to certain characteristics, it can be easier to study distant solar systems than the one we actually live in. Two mysteries that a new perspective could help scientists solve include the disk of dust that fills and surrounds our solar system and the magnetic bubble created by our star that envelops our solar system.

05_23_interstellar_solar_system Our solar system, encased by its heliosphere, barrels into the interstellar space that surrounds it. Scientists have spent decades dreaming of a mission that would purposely examine our solar system from the outside. NASA/Goddard Space Flight Center

Scientists believe that studying the structure of dust disks around a star can unlock secrets of what sort of solar system the star may host. That’s because the dust is created as a byproduct of building planets. “It’s sort of a fossil, it holds the history of the solar system’s formation,” Brandt said.

The second target we need to get beyond our solar system to properly study is the heliosphere, the magnetic bubble produced by charged particles streaming off our sun and out into space. Every star has its equivalent, but those we’ve studied look different—they shine brightly with a type of light ours doesn’t seem to emit much of. “It turns out that none of the astrospheres that we’ve observed in the sky come even close to ours,” Brandt said.

In space science as in so many things, it may take leaving home and getting a new perspective on things to truly understand our place in the world.

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