Mariner 3 launched 1964

Mariner 3, which launched November 5, 1964, was NASA's first attempt to study Mars.  Unfortunately, an hour into the flight, telemetry indicated the solar panels were not working.  It seemed that a separation had not taken place properly.  Eight hours later the batteries in the probe died and the mission was scrapped.

Three weeks later, Mariner 4 was launched successfully to the Red Planet.

Pioneer Venus Multiprobe releases 4 probes into Venusian atmosphere 1978

The Pioneer Venus Multiprobe, Pioneer Venus 2 or Pioneer 13, launched in 1978, released one large and three smaller probes into the Venusian atmosphere, December 9, 1978.  The probes collected data as they descended toward the surface.  They did not carry photographic instruments and were not designed to survive landing.  However, one did survive and continued transmitting for an hour after impact.  

The probes found temperatures between 448 °C and 459 °C at the surface.  Pressure on the ground is between 86.2 bar and 94.5 bar.