Rank 70 documents Mariner 2 — the first successful interplanetary spacecraft and the mission that turned Venus from a bright mystery into a measured furnace. Launched 27 August 1962 after Mariner 1 failed due to a guidance error, the 203.6 kg hexagonal bus rode Atlas-Agena B toward Earth's sister planet with six science sensors including a 9.9 kg microwave radiometer alone. On 14 December 1962 Mariner 2 passed 34,854 km from Venus, measuring surface temperatures roughly 300–400°F and confirming a thick carbon dioxide atmosphere with no magnetic field — data that rewrote planetary science at 8⅓ bits per second across a 34-million-mile link. Last signal arrived 3 January 1963. William Pickering's JPL team and project manager Jack James delivered what no nation had achieved: a robotic visit to another world. Wallimilist renders the hexagonal bus with radiometer mast, dual solar wings, Venus ochre disc, and vertical MARINER 2 title exactly as the master PNG dictates — venus palette, interplanetary void, and curator copy on first flyby heritage.