Mariner 4 launched for Mars in 1964 after its twin failed

NASA launched Mariner 4 toward Mars on 28 November 1964, just two days before the launch window closed and three weeks after its identical twin, Mariner 3, was lost. After a 228-day journey it flew past Mars on 14 July 1965, the first spacecraft to return close-up pictures of another planet.

How the second try got there

• 5 Nov 1964: Mariner 3’s payload shroud fails to jettison; its solar panels cannot open, and it drifts into solar orbit as a dead spacecraft.
• 28 Nov 1964: Mariner 4 lifts off under a hastily redesigned, all-metal shroud, which separates cleanly.
• 5 Dec 1964: a single course correction aims it to pass 5,000 to 6,000 miles from Mars.
• Early 1965: a plasma probe component fails and a Geiger tube stops in March, while other instruments keep sampling interplanetary space.
• 14 July 1965: about 25 minutes of observation near Mars yield 21 full pictures.

The 575-pound craft held its orientation with nitrogen gas jets, helped by an experiment: steerable pressure vanes on the tips of its four solar panels that used the push of sunlight to trim its attitude.

Its radio was tiny for the distance. A 10-watt signal arrived at the Deep Space Network’s 85-foot dishes as about a billionth of a billionth of a watt, yet in late 1965 Mariner 4 set a communications distance record of 190 million miles.

The probe kept working long after its job was done. In October 1967 engineers woke it for attitude-control tests to help Mariner 5, then on its way to Venus. It finally ran out of control gas and fell silent in late December 1967, more than three years after launch; NASA’s own histories differ on the exact day, giving 21 and 31 December.