Apollo 13 was launched on 11^th April 1970 with Lovell, Fred Haise and John Suigert. Unfortunately an oxygen tank ruptured, so landing on the moon had to be cancelled. The power and survival systems of the Lunar Module was used to swing behind the moon and return to Earth four days after take-off.

The Americans waited nine months before launching Apollo 14. Modifications had been carried out to the spacecraft to prevent a recurrence of the previous malfunction.

Captain Shepard and Commander Edgar Mitchell landed the Lunar Module in the rugged Fra Mauro region of the moon, while Stuart Roosa remained in lunar orbit in the Command Module.

Shepard and Mitchell spent nine hours exploring an area containing some of the oldest rocks that had yet been recovered. They collected 96 lbs of geological samples and deployed scientific instruments. They returned to Earth on 9^th February 1971.

On 26^th July 1971 Apollo 15 was launched, manned by Colonel Scott, James Irwin and Alfred Worden. Scott and Irwin spent nearly three days on the lunar surface near the Apennine mountain range, which is one of the highest on the moon.

They deployed more scientific instruments and collected 200 lbs of rock, including a crystalline piece of the original lunar crust, which was about 4.6 billion years old.

They left a television camera on the surface to record their departure. Before leaving orbit a satellite was launched to transmit data about gravitational, magnetic and high-energy fields in the lunar environment. They returned to Earth