Today marks the 58th anniversary of the launch of Sputnik 1, the first artificial Earth satellite ever to grace orbit, as well as the starting pistol of the space race. As if that isn't enough of a reason for space enthusiasts to raise a glass, the anniversary coincides with the kickoff of World Space Week (WSW), the largest public space celebration in the world, which features 1,400 events spanning 80 countries.
The theme for WSW 2015 is "discovery," which is fitting given all the incredible new frontiers the space community has explored over the last year, such as Pluto, Ceres, and Comet 67P. But considering that it is also the anniversary of Sputnik 1, the theme also presents a great opportunity to revisit the discoveries of our very first space explorer. After all, Sputnik is often remembered as a powerful historical shock wave—an event, more than an object—that its actual scientific payload can be easily overshadowed by its cultural impact.
To that point, the most important discovery made by this tiny probe—which was only the size of a beach ball—was that spaceflight is actually possible. In one fell swoop, the Soviet space program inaugurated most of the astronautical techniques that are still around today, including the use of multistage rocket engines, onboard radio transmission, and the precise calculation of orbital course trajectories. It's one thing to pioneer theories of spaceflight, but quite another to demonstrate them in action, and that was the Soviet Union's main intent with Sputnik 1.
A stamp commemorating Sputnik 1. Image: Russian Federation
Interestingly, the satellite was originally intended to be several times larger, with a much more complex suite of instruments, but Soviet rocket lead Sergei Korolev decided to slim down the mission in order to launch it faster and nab the "first satellite ever" milestone—a smart move in retrospect. The larger satellite project was kicked down the line and eventually became Sputnik 3, which launched a few months later on May 15, 1958.
Even though Sputnik 1 had been drastically pared down version of the original, it still made numerous landmark discoveries about outer space. The satellite was equipped with temperature and pressure sensors and frequently transmitted readings about its environment via radio. Scientists figured out the density of Earth's upper atmosphere by studying the drag on the spacecraft, while Sputnik's radio signals were used to map out the electron distribution in the ionosphere.
What's more, the satellite was prepared to record its encounters with any errant meteoroids that it might encounter in orbit. The spacecraft was filled with pressurized nitrogen set to 1.3 atm, and any breaches or punctures would be noticed by its onboard barometer, and transmitted back to Earth. No such events actually occurred, but the infrastructure provided a workable framework for interrogating space debris in future missions.
Sputnik 1 continued to pass on information about its exotic surroundings to captivated scientists around the world, until its batteries ran out about three weeks later on October 27. On January 4, 1958, the spacecraft burned up in the atmosphere after completing roughly 1,400 orbits and having traveled 70 million kilometers.
The impact of Sputnik on popular culture, public policy, and Cold War tensions is well documented, and there can be no understating the satellite's role in history. But as much as this plucky little probe was an undeniable warning shot from the USSR, showcasing the nation's military potential, it was first and foremost a science experiment.
Just 58 short years later, we have left footprints on the Moon, found water on Mars, and entered interstellar space, and we have a lot more to look forward to—including, perhaps, the first manned voyages to other planets.
But it all started on that chilly Friday night in October, when Sputnik 1 became humanity's first emissary to the world beyond on our own.