Apollo 11 was the spaceflight that first landed humans on the Moon. Commander Neil Armstrong and lunar module pilot Buzz Aldrin formed the American crew that landed the Apollo Lunar Module Eagle on July 20, 1969, at 20:17 UTC. Armstrong became the first person to step onto the lunar surface six hours and 39 minutes later on July 21 at 02:56 UTC; Aldrin joined him 19 minutes later. They spent about two and a quarter hours together outside the spacecraft, and they collected 47. 5 pounds (21. 5 kg) of lunar material to bring back to Earth. Command module pilot Michael Collins flew the command module Columbia alone in lunar orbit while they were on the Moon’s surface. Armstrong and Aldrin spent 21 hours, 36 minutes on the lunar surface at a site they named Tranquility Base before lifting off to rejoin Columbia in lunar orbit.
Ganymede: Ganymede is both the largest moon of Jupiter, our Solar System's planetary behemoth, as well as the largest moon in our entire Solar system. Observations of Ganymede by the HST in 2015 suggested the existence of a subsurface saline ocean. This is because patterns in auroral belts and rocking of the magnetic field hinted at the presence of an ocean. It is estimated to be approximately 100 kilometers deep with a surface situated below a crust of 150 kilometers. The team of astronomers used the same HST technique to observe the little moon as they did for discovering the small moons of Pluto in 2006, 2011, and 2012. Several earlier hunts around Makemake had not succeeded in spotting it. "Our preliminary estimates show that the moon's orbit seems to be edge on, and that means that often when you look at the system you are going to miss the moon because it gets lost in the bright glare of Makemake," commented Dr. Alex Parker in an April 28, 2016 Hubble Press Release. Dr. Parker, who led the image analysis for the observations, is of the Southwest Research Institute in Boulder, Colorado. A Moon For Makemake. The observations of April 2015, that unveiled Makemake's tiny moon, were made with HST's Wide Field Camera 3. HST's ability to observe faint objects close to bright ones, along with its sharp resolution, enabled the astronomers to spot the moon that was being masked by Makemake's glare. The announcement of the dim little moon's existence was made on April 26, 2016 in a Minor Planet Electronic Circular.