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DIRECTING INTERSTELLAR SPACE TRAVEL
by Liz Fuller-Wright, Princeton.edu
THE TWIN VOYAGER SPACECRAFT CAPTURED THE PUBLIC IMAGINATION IN THE 1970S AND ’80S AS EARTH’S FIRST AMBASSADORS TO THE OUTER PLANETS, PROVIDING CLOSE-UP IMAGES OF JUPITER, SATURN, URANUS, AND NEPTUNE.
Voyager 2 leapt skyward first, on August 20, 1977, followed a few weeks later by Voyager 1 on Sept. 5.
Early career astrophysicist Jamie Rankin, HBS, Physics and BA'11 Music Composition, is now playing a leading role on the team that continues to track the aging probes Voyager I and II, each more than 10 billion miles from Earth. Born in 1988, Rankin is one of the youngest researchers ever to hold such an elevated title.
“Voyager is an amazing mission, and I’m so grateful for this opportunity,” says Rankin, who as a graduate student at CalTech did the first thesis on Voyager’s data from interstellar space. Today, she is an associate research scientist at Princeton University and an instructor of the space physics laboratory class.
MAPPING THE EDGE OF THE SOLAR SYSTEM
“The science still coming from the Voyagers is amazing—and underappreciated,” says Rankin. “Everything—everything—that we’ve measured in space gets filtered through the solar wind—through the sun and its plasma and magnetic fields. And everything measured from Earth-based telescopes is also filtered through our atmosphere.“ The very first time that we could measure space directly, without being disturbed by the sun, was when Voyager crossed into the interstellar medium.”
One thing Voyager measured was the level of incoming radiation, potentially deadly outside the heliosphere at almost ten times higher than inside the Earth’s atmospheric bubble. “The solar wind is actually protecting us,” Rankin says, from incoming radiation that in the heliospheres is ten times greater than that of the Earth’s atmospheric bubble. “Before the Voyagers got out here, nobody knew quite how much we were being shielded.”
The Voyagers also discovered that the sun interacts with its boundary differently than scientists had expected. When the Interstellar Mapping and Acceleration Probe (IMAP) launches in 2025 in a heliophysics mission, it will map out even better that elusive boundary zone in great detail, providing a comprehensive picture to complement the deep but geographically limited data.
Voyager 1 is now billions of miles outside the heliopause, as far from that boundary as Neptune is from Earth, and speeding onward at about a million miles a day. And it’s still making remarkable discoveries, says Rankin.
Fifty years following their launch (more than ten years before Raskin was born) the Voyagers are aging. And, at such great distances away— it takes around two days to send and receive a message—they have experienced glitches. This past August inadvertent maneuvers pointed the probe's antenna slightly away from Earth and caused a communication disruption on Voyager 2. NASA was able to successfully establish full communications with Voyager 2, and as deputy director, Jamie Rankin was there coordinating data and working for the correction.
