October 11, 1957 – Sputnik-Spotting With MIT’s IBM 704

IBM 704 Computer with Operator. Photo: Lawrence Livermore National Laboratory

On October 11, 1957, the enormous IBM 704 computer at Massachusetts Institute of Technology’s Computation Center produced the first “satisfactory orbit” calculations for the Smithsonian Astrophysical Observatory’s Sputnik 1-spotting mission.  Operation Moonwatch, a group of amateur astronomers organized by Observatory Director Fred Lawrence Whipple, was working feverishly in Cambridge, Massachusetts since Sputnik’s October 4th launch to develop the mathematical models to accurately calculate and predict where the first man-made Earth satellite would appear in the sky at any given time.  If they could determine the position of Sputnik 1, they could derive its “orbital elements”, or “parameters required to uniquely identify a specific orbit” – scientist talk for “where exactly is the satellite now and where will be it be in five, ten, or fifteen minutes?”.

The IBM 704, introduced in 1954, was the first mass-produced computer with floating-point arithmetic hardware and core memory (instead of tubes).  Computer languages FORTRAN and LISP were first developed for use with the 704.  It was able to execute up to a speedy 40,000 instructions per second.

The astronomers had three targets to work with: the Sputnik 1 satellite with its radio transmitter; a detached nose cone from the satellite; and the satellite’s discarded booster rocket.  Early in the morning of October 11th, at around 7:00 AM, the state-of-the-art IBM 704 was able to lock on and calculate the critical Earth-orbit data for the booster rocket.

Being able to accurately locate objects orbiting the Earth and passing over the United States was of great national security interest.  The questions on everyone’s mind since the Soviet Union’s successful Sputnik 1 launch were: Would the Soviets send up an ICBM, now that they had the technology?  And: How soon?