On this day in ’62: a typo, a doomed spacecraft and a costly explosion

22 Jul 2016

On this day in 1962, NASA hit one of its most embarrassing lows. Mariner 1, the space agency’s first planetary mission, exploded in under five minutes, and a typo was to blame.

Intended to be a flyby of Venus, Mariner 1 was dreamt up, fired up and blown up amid an increasingly competitive space race.

Back in 1962, the idea of visiting alien planets was at its height. Mariner 1’s goal – ultimately achieved by Mariner 2 – tapped into this thirst, with its demise a $147m disaster (it cost $18.5m at the time).

Mariner 1

Venus fly trap

The underlying code behind space missions in the 1960s was not all typed into software, shared on an internal system and edited, uploaded and revised on screen. Rather it was an era of tangible, manual programming, with punch cards representing some of what we call script today.

An error in the punch cards supporting the Mariner 1 mission meant that, once a hardware failure hit the spacecraft, immediate disaster loomed.

An on-board guidance antenna failed just a few minutes into the flight, meaning the supporting software was needed to guide the spacecraft into position.

Yet a missing ‘bar’ in the punch cards meant that the spacecraft veered off course, and engineers could not correct it.

Mariner 1

The Mariner 1 launch. Image via YouTube

Timing issues

The bar in the written code was key as it represented the bridging delay between two radar systems on board – which totalled some 43 milliseconds. Without it, the radars were not in sync, causing the spacecraft to malfunction.

As it headed towards “the North Atlantic shipping lanes or in an inhabited area”, according to NASA, a critical decision was made.

Just six seconds before Mariner 1 separated from its launch vehicle – at which point a manual destruction would no longer be controllable – NASA engineers pressed the big red button.

And so ended the first planetary space mission, in a blaze of costly failure. NASA has lost astronauts in other missions, so this financial disaster was nothing as costly as, say, Challenger in 1986 or Columbia in 2003.

Luck or design

It appears Mariner 1’s untimely end was more bad luck than bad design. After all, the underlying faulty code had been used in previous Ranger missions (which saw unmanned spacecraft photograph the moon up close) “with no ill effects”, according to Paul Ceruzzi’s book Beyond the Limits: Flight Enters the Computer Age.

The only reason the flawed code was discovered on the doomed Mariner 1 mission was due to the previous hardware fault in an antenna.

Mariner 2 image, via NASA

Mariner 2. Image via NASA

For Mariner 2, which took off under two months after Mariner 1, that the software was finally fixed.

Mariner 2 passed within about 34,000km of Venus, sending back valuable new information about interplanetary space and the Venusian atmosphere. A roaring success, preceded by an explosive failure.

Main explosion image via Shutterstock

Gordon Hunt was a journalist with Silicon Republic