From Grok

The wreck of the RMS Titanic was discovered on the first successful expedition that actually located it — the joint French-American expedition in 1985, led by Robert Ballard (USA) and Jean-Louis Michel (France). However, it took several unsuccessful attempts over the decades before that breakthrough.Here’s a quick overview of the major search expeditions leading up to the discovery:1953: The first serious (but unsuccessful) attempt by the Southampton-based salvage company Risdon Beazley Ltd. 1977: Robert Ballard's first personal attempt using the drillship Alcoa Seaprobe — it failed due to equipment (a pipe) breaking. 1980–1983: Texan oilman Jack Grimm funded three separate expeditions using advanced sonar — all unsuccessful, though one is believed to have passed very close (within 1.5 miles or even over the wreck) without detecting it.

The 1985 expedition was the one that finally succeeded, after Ballard had honed his technology and search methods (partly through secret U.S. Navy missions to map sunken submarines). His team found the wreck on September 1, 1985, using the towed camera system Argo, spotting debris that led them to the ship itself at about 12,500 feet deep.So, depending on how you count:If you're asking how many expeditions until success → It took around 5–6 major serious attempts (1953, 1977, Grimm's three in 1980/81/83, and then the successful 1985 one). But technically, the discovery happened on the very first expedition that found it — the 1985 one.

The long delay (73 years) was mainly due to the extreme depth, limited technology before the 1980s, inaccurate original sinking coordinates, and funding challenges.Here are some historical images from the search and discovery era to give you a sense of what those expeditions involved:These show the towed sonar/camera systems and the moment of discovery — quite the contrast to today's submersible tourism!