piccard_walsh_trieste Jacques Piccard (right) pictured with Don Walsh, pictured inside the bathyscaphe Trieste at the bottom of the Marianas Trench in 1960.



At 10,911 metres down the trench is the deepest point on Earth - only Piccard and Walsh have ever been there.



Piccard designed and built Trieste with his father, Auguste, who was a notable engineer that had twice held the record for the highest manned balloon flight. Star Trek creator Gene Rodenberry has said he named his character Jean-Luc Picard in honour of Auguste and Jacques.



(Image: NOAA)

A Trieste bathyscape like that used in the Marianas mission being lifted out of the water. The large tank over the sphere was filled with gasoline - cheap, incompressible and buoyant.



Trieste controlled buoyancy by swapping some gasoline for seawater, and ascended by dropping balls of iron shot. This approach was directly copied from the way Auguste's balloons were controlled.



(Image: US Naval Historical Center) Advertisement

Piccard and Walsh travelled downwards for more than five hours in their cramped sphere before reaching the bottom.

This is how Piccard later described the scene: ""The bottom appeared light and clear, a waste of snuff-colored ooze. Indifferent to the nearly 200,000 tons of pressure clamped on her metal sphere, the Trieste [made] token claim, in the name of science and humanity, to the ultimate depths in all our oceans - the Challenger Deep."



After noticing cracks in the windows, Piccard decided to start the ascent after just 20 minutes. It took three hours to reach the surface.



The two explorers reported seeing shrimp and a fish at the bottom - the latter claim caused controversy among scientists who said they couldn't exist at such depths. The deepest living fish have recently been filmed at a depth of 7.7km [link with video].



(Image: US Naval Historical Center)

In 1968, Piccard built the Grumman/Piccard PX-15, also known as the Ben Franklin, for a six-man crew.



Equipped with only minimal propulsion, it was designed to spend a month underwater studying the Gulf Stream by simply drifting with it. The 15-metre craft carried tonnes of lead-acid batteries to provide power and submerged off Florida on July 14, 1969.



This photo shows the crew shortly before submerging.



(Image: NASA)

The Ben Franklin was studded with sensors to take oceanographic measurements, but it also provided a chance for NASA to study a crew confined in close, isolated quarters for a long period.



The craft's mission coincided with the Apollo 11 moon landing and was relevant to NASA's ambitions to send humans on long space missions, such as would be required on space stations.



A crew member from the space agency studied his fellows throughout the journey, noting everything from sleep patterns to morale.



(Image: NASA)

Conditions on board the Ben Franklin were far from comfortable. To conserve electricity the craft didn't use heaters and the crew struggled to stay warm throughout the mission. The temperate was usually around 14 °C, while humidity fluctuated between 73 and 100%.



The hot water system failed early on, reducing the crew to making up their dehydrated rations with tepid water.



(Image: NASA)

The Ben Franklin resurfaced on August 14, south of Halifax, Nova Scotia, Canada. It had travelled 2,700km (1444 nautical miles) at depths between 180 and 600m.



(Image: NASA)