PLANNING THE NEXT MISSION

How about a dedicated interstellar probe? We speak with scientist Kirby Runyon about a far-flung mission

Runyon is part of a team at the Johns Hopkins University Applied Physics Laboratory working on an Interstellar Probe concept mission that would fly straight out to study interstellar space without visiting any planets on the way.

Why is it important to study the interstellar medium (ISM) in situ?

Finding out how the Sun interacts with the ISM in situ is ‘astrophysics you can touch’. To understand the gas, dust and plasma that we can observe – but not touch – surrounding and interacting with other stars, we need to understand how our own Sun’s ‘weather’ is affected by what lies just beyond the Solar System. By having an interstellar probe study the ISM in situ, it will be providing ground truth to both astrophysics and the physics of the Sun.

If the project goes ahead, what would the timescale be?

If NASA selects the Interstellar Probe concept, we would hope for a launch in the early 2030s on a 50-year mission to last into the 2080s. Because it would leave the Solar System far faster than any spacecraft to date, it would travel the distance to Pluto in only about four years – compared to the almost ten years it took New Horizons.

What are the main engineering challenges beyond New Horizons?

The biggest challenge for such a long-lived, 50-year mission is designing and building a spacecraft that can last that long. Making a long-lived spacecraft means eliminating and reducing moveable parts, which can wear out, and ensuring the spacecraft has enough power from plutonium batteries to last that long. The Voyager craft were designed to last four years, but they’ve both been operating since 1977 – 44 years! But designing a spacecraft to last multiple decades is very different from a spacecraft

‘accidentally’ lasting that long.