<P> Four descents have been achieved . The first was the manned descent by Swiss - designed , Italian - built , United States Navy - owned bathyscaphe Trieste which reached the bottom at 1 : 06 pm on 23 January 1960 , with Don Walsh and Jacques Piccard on board . Iron shot was used for ballast , with gasoline for buoyancy . The onboard systems indicated a depth of 11,521 m ( 37,799 ft ) , but this was later revised to 10,916 m ( 35,814 ft ) . The depth was estimated from a conversion of pressure measured and calculations based on the water density from sea surface to seabed . </P>
<P> Four descents have been achieved . The first was the manned descent by Swiss - designed , Italian - built , United States Navy - owned bathyscaphe Trieste which reached the bottom at 1 : 06 pm on 23 January 1960 , with Don Walsh and Jacques Piccard on board . Iron shot was used for ballast , with gasoline for buoyancy . The onboard systems indicated a depth of 11,521 m ( 37,799 ft ) , but this was later revised to 10,916 m ( 35,814 ft ) . The depth was estimated from a conversion of pressure measured and calculations based on the water density from sea surface to seabed . </P>
how many times have we been to the bottom of the mariana trench
how many times have we been to the bottom of the mariana trench
Four
Four