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Why scientists want NASA to approve an Interstellar Probe that would plumb the depths of the galaxy

Voyager spacecraft (NASA)
Voyager spacecraft (NASA)

Scientist Ralph McNutt, Jr. wants NASA to approve an Interstellar Probe that would explore the expansive stretches of space beyond the influence of our sun.

As chief scientist for space science at the Johns Hopkins University Applied Physics Laboratory, McNutt is one of many experts staunchly advocating for the mission, which would launch in 2036. If approved, the probe would pick up where the 1977 Voyager mission leaves off in exploring the galaxy.

Voyager 1 and 2 were sent to cross the solar system’s outer limits, but the mission is taking a lot longer than planned. Initially designed to last only four and a half years, the spacecrafts are now nearly 45 years old.

“The idea with an Interstellar Probe is to actually take that next big, dedicated step and to be able to actually redo all the science that we’ve been doing before with modern instrumentation,” McNutt says.

The Voyager mission showed scientists that the heliopause — the boundary between the sun’s solar wind and interstellar space — is longer than originally thought. The Interstellar Probe would bring advanced tools beyond the boundaries of our solar system twice as fast as the Voyager, McNutt says.

Pinpointing the edge of our solar system opens the possibility of discovering unknown planets, civilizations or even the origins of life on Earth, McNutt says. And scientists may learn the chilling truth behind why far-away species went extinct, staff writer Richard Stone writes in Science.

“A piece of the puzzle is trying to understand how those systems interact with the interstellar medium and what are the implications for life elsewhere in the galaxy,” McNutt says.

To reach past our solar system, the probe would whip around Jupiter for a gravity boost and then slingshot to the edge of the solar system. The probe would arrive 16 years later, a much shorter time period than the Voyager. McNutt knows he’ll be dead by the time the probe would return 50 years later — but it’s about the long-term, he says.

“Consider the great cathedrals of Europe. Those were not built in a generation. They were literally built, some of them, over hundreds of years,” he says. “Future generations will look back to 2022 and go, ‘Wow, this is something in the history books.’ So it’s a matter of perspective and being able to kind of jump back and forth.”

Critics of the proposal point out the stunning sticker price needed to launch the probe: $3.1 billion. But McNutt says continuing to learn about space is worth the cost.

“You can either step backwards or you can step to the future, and you step to the future by doing the new challenges and the new challenging things,” he says. “And that’s how you advance. And you either advance or decline. You don’t really have a choice. You can’t stand still.”

Chris Bentley produced and edited this interview for broadcast with Gabe Bullard. Jeannette Muhammad adapted it for the web.

This article was originally published on

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