Four years in the making, a pragmatic mission concept for an interstellar probe would go beyond the Voyager Interstellar Mission, in which two spacecraft left Earth in the 1970s and are now the most distant human-made objects. The team behind the project detailed their proposal today at the annual general assembly of the European Geosciences Union.
This probe would pass the solar system’s heliosphere, the area around us where the Sun’s solar winds play a role, filling space with radiation and magnetic fields. (Earth’s magnetosphere protects us from much of this, and the absence of such a sphere on Mars and Venus is clear in their divergent planetary evolution). To an extent, the heliosphere also acts as a shelter protecting our solar system from interstellar radiation.
“The interstellar probe represents this snapshot in time, of where we are on the solar journey through the galaxy,” said Pontus Brandt, an astrophysicist at Johns Hopkins University and a member of the interstellar probe team, during today’s presentation. “By exploring the heliosphere and the interstellar medium today, in its current state, the interstellar probe will ultimately allow us to understand how our home in the galaxy formed and also where we’re going next.”
The farthest human-made object from Earth is Voyager 1, launched in 1977 and now over 152 astronomical units from us, in which one AU is the average distance between the Sun and Earth. In baser terms, Voyager 1 has traveled over 14 billion miles to date, while its sibling, Voyager 2, has gone over 11.7 billion miles. New Horizons, launched in 2006, is now just beyond Pluto. The proposed probe, which would launch in the early 2030s, would make it to the heliosphere boundary in 15 years, compared to the Voyagers’ 35-year schlepp to the same place. The probe would be built to last 50 years, with the ultimate goal of making it 1,000 astronomical units out, dwarfing previous strides by human spacecraft and delving into the interstellar medium—the great void beyond the reaches of our Sun.
“The interstellar probe will go to the unknown local interstellar space, where humanity has never reached before,” Elena Provornikova, the Interstellar Probe heliophysics lead from the Johns Hopkins Applied Physics Lab in Maryland, said in a European Geosciences Union press release. “For the first time, we will take a picture of our vast heliosphere from the outside to see what our solar system home looks like.”
To get out there at such a clip, the team proposes slingshotting the probe around Jupiter, in a manner akin to Cassini. That beats shooting the probe past the Sun, where it would need a massive heat shield to survive, cutting down the number of scientific instruments the craft could take on its journey.
The scientific objectives of the probe are threefold. As presented by Provornikova earlier today, they are to better understand the physical processes that shape the heliosphere, to better understand how activity in the interstellar medium affects the heliosphere, and to discover and quantify the properties of the local interstellar medium.
At the end of this year, the interstellar probe team will propose the craft to NASA in a comprehensive report. Here’s hoping they get the funding to move forward.