Suzanne Dodd (BS ’84) has managed NASA’s Voyager Interstellar Mission since 2010. She joined the project as a sequence engineer in 1984, designed the closest-approach command sequence for Voyager 2’s Neptune flyby, and later spent 11 years on campus running the Spitzer Science Center and IPAC before returning to the Lab.
This spring, The New York Times spent time with Dodd’s team at JPL, reporting on what engineers call the Big Bang: a coordinated reconfiguration of the spacecraft’s electrical systems meant to squeeze a few more years out of two probes launched in 1977.
The problem is the power budget. Each spacecraft’s radioisotope thermoelectric generators produced about 470 watts at launch. Voyager 2 is now down to 216 watts and three of its 10 instruments; Voyager 1 has slightly less power and two instruments still collecting data. Heaters help keep the hydrazine lines from freezing, while residue from the propellant system is narrowing the lines. Lose the wrong watt and a thruster gets too cold, the antenna drifts off Earth, and the mission ends.
Piecemeal savings were no longer enough. JPL engineer David Woerner argued for making a slew of changes at once so the heat and power ledgers stayed balanced. After nine months of analysis, the team ran it on Voyager 2 in three steps: a 40-minute trial in May, a six-hour run in June, and a permanent switch in July. The payoff is roughly 10 watts, enough to extend the mission to about 2031. Voyager 1 gets the same treatment in the coming weeks, with a target of 2030.
Mission manager Kareem Badaruddin told the Times that nobody enjoys working this close to the edge, but the team has no other option.
With the recovered power, the team is weighing whether to switch some dormant instruments back on, which carries its own risk of losing a spacecraft entirely. Voyager 2 launched on August 20, 1977, and Voyager 1 on September 5, 1977. Dodd expects them both to reach the anniversary: “I’m pretty confident that they both make it.”
Read the full story in The New York Times.