An Interstellar Shout Acknowledged

Launched in 1977—the selfsame year a young film-maker named George Lucas startled the world with an unlikely hit titled Star Wars, Episode IV, A New Hope—NASA’s Voyager program is predicated upon two robotic interstellar probes, Voyager 1 and Voyager 2, tasked in kind with studying the outer Sol System and the vastness of interstellar space.

The Voyagers’ launch windows took advantage of favorable alignments of the gas-giants Jupiter and Saturn, and the ice-giants Uranus and Neptune, to which the two probes journeyed and collected data prior to proceeding outbound, accelerating all the while, into the ineffable void beyond the Sun’s heliosphere.

Both Voyagers remain in operation beyond the outer-boundary of the sun’s solar winds, dutifully collecting and transmitting multiple daily hours of useful data back to their NASA masters on Earth.

On 21 July 2023, contact with Voyager 2 was lost after a programming error skewed the probe’s transceiver-array a few critical degrees away from Earth. Fortuitously, on 06 August, following a 16-day communication blackout, NASA reported contact with the spacecraft had been reestablished over a distance of some 12.3-billion miles.

NASA’s communication with Voyagers 1 and 2 is facilitated by the agency’s Deep Space Network (DSN), a worldwide aggregation of U.S. spacecraft communication ground segment facilities spanning the United States (California), Spain (Madrid), and Australia (Canberra). In addition to supporting interplanetary spacecraft missions, DSN performs radio and radar astronomy observations conducive to the exploration of the cosmos, and supports selected Earth-orbiting missions. DSN falls under the auspices of NASA’s Jet Propulsion Laboratory (JPL).

Had NASA teams failed to otherwise reestablish contact with Voyager 2, the probe would have remained dark until October and the auto-execution of a corrective protocol.

NASA referred to its successful attempt to reorient Voyager 2 as an interstellar shout. Persisting in the metaphor, NASA’s shout, traveling at the speed-of-light, took approximately 18.5-hours to reach Voyager 2. A total of 37-hours passed between the time NASA transmitted the shout and Earth-bound controllers determined Voyager 2 had heard and heeded the command to reorient its transceiver array.

Following the so-called shout’s acknowledgement, NASA set forth in a statement: "At 12:29 a.m. EDT on Aug. 4, the spacecraft began returning science and telemetry data, indicating it is operating normally and that it remains on its expected trajectory.”

Nearly fifty-years after its launch, five of Voyager 2’s sensory instruments remain operable—each using a phenomenally-miserly four-watts of power annually. In April 2023, NASA's Jet Propulsion Laboratory devised means by which to boost Voyager 2’s backup power to an extent commensurate with the probe’s remaining operational until 2026.

FMI: www.nasa.gov