This second Sputnik moment in the history of human exploration has rightly rekindled the awe humans felt when they first looked into the night sky.
On August 25, 2012 and around 18.78 billion km from Earth, the Voyager 1 space probe became the first human-made object to breach the interstellar medium (ISM), the matter that exists between stars in the universe. The primary reason it has taken a year for astrophysicists to deem this event as having happened is that the signs of breaching the ISM were not all detected simultaneously nor have they been understood fully. In fact, as if playing on their confusion, Voyager 1 beamed home a series of signals in October-November, 2012, that have been studied for their meaning since then. In three papers published in Science in June this year, scientists deduced that the probe had stumbled into a region — lying on the cusp of the ISM — astronomers didn’t know existed. Finally, and with the help of a natural disturbance promulgated by our Sun, astronomers from NASA and several universities, led by the University of Iowa, detected signals from Voyager 1 in April, 2013, that implied the incidence of cosmic rays and the density of ionized gas around the probe had increased, and the direction of the magnetic field in the space around the probe had changed: all signs of Voyager 1 becoming humankind’s first eyes and ears in the world between stars.
When the twin Voyager probes were launched in 1977, the space age was only two decades old. Those who built and now operate them, from the NASA Jet Propulsion Laboratory, Pasadena, California, had the audacity to equip the probes to function for almost four decades (Voyager 2 is currently 15.3 billion km from Earth). The durability of the probes and the careful management of resources have awarded us with the chance to directly study the outermost reaches of the Solar System, within which great astronomical observations are being expected. This attitude of careful management has also paid off with other NASA missions, such as the WISE asteroid-hunter and the Spitzer space telescope before, and should once again with the Kepler space telescope. And while nobody is sure of what to expect from Voyager 1, that the probe is now bathed in particles arising from stars other than just the Sun is opportunity enough. Its particles and fields science experiment will function till 2020, until when the small nuclear battery on-board will be able to power them. After that, the Golden Record, a gold-plated disc containing photos of and sounds from Earth, added to the payload just in case other life-forms encounter the probe, will preserve Voyager 1’s ambassadorship. This second Sputnik moment in the history of human exploration has rightly rekindled the awe humans felt when they first looked into the night sky.