The Science Life
To catch the faint signal of a spacecraft leaving the solar system, you have to listen very carefully. At NASA’s Jet Propulsion Laboratory in Pasadena, Calif., that’s Suzanne Dodd’s job.
Dodd (below) is project manager for NASA’s twin Voyager probes, launched in 1977 to explore Jupiter and Saturn. Voyager 2 did that and more, as the first probe to fly by Uranus, in 1986, and Neptune, in 1989. It’s now 15 billion kilometers from Earth and headed out of the solar system.
Its twin is farther ahead. After visiting Saturn, Voyager 1 headed directly toward interstellar space, beyond the bubble of charged particles that surrounds the solar system. Voyager 1 is now more than 18 billion kilometers from Earth; Dodd has to wait 17 hours each way for a message to travel between Earth and the probe. Last summer the craft crossed through a strange transition, where the flood of charged particles from the sun dropped to nearly nothing but the sun’s