On this day in 1976, NASA publicly unveils its first space shuttle, the Enterprise, during a ceremony in Palmdale, California. Development of the spacecraft cost almost $10 billion and took nearly a decade. What followed was a heroic, remarkably productive 30-year service history, crassly underrated by much of the public.

As configured, the space shuttle, or STS, consisted of three major components: a winged orbiter that carried both crew and cargo; an external tank containing liquid hydrogen (fuel) and liquid oxygen (oxidizer) for the orbiter’s three main rocket engines; and a pair of large, solid-propellant, strap-on booster rockets. At liftoff the entire system weighed 2,200 tons and stood 184 feet high. During launch the boosters and the orbiter’s main engines fired together, producing about 7 million pounds of thrust.

The boosters were jettisoned about two minutes after liftoff and were returned to Earth by parachute for reuse. After attaining 99 percent of its orbital velocity, the orbiter had exhausted the propellants in the external tank. It then released the tank, which disintegrated on reentering the atmosphere. Although the orbiter lifted off vertically like an expendable rocket launcher, it made an un-powered descent and landing similar to a glider.

Five complete Shuttle systems were built and used on a total of 135 missions from 1981 to 2011, launched from the Kennedy Space Center (KSC) in Florida. Operational missions launched numerous satellites, interplanetary probes, and the Hubble Space Telescope (HST), conducted countless science and medical experiments in orbit, and participated in construction and servicing of the International Space Station. The Shuttle fleet’s total mission time was 1322 days, 19 hours, 21 minutes, 23 seconds.

Over those 135 missions, 14 STS astronauts gave their lives in furtherance of the ancient impulse compelling mankind to relentlessly come to know the unknown universe.