1971 in science

Astronomy and space exploration

• January 31 – Apollo program: Astronauts aboard Apollo 14 lift off for a mission to the moon.
• February 5 – Apollo 14 lands on the Moon.
• February 9 – Apollo program: Apollo 14 returns to Earth after the third manned moon landing.
• May 19 – Mars probe program: Mars 2 is launched by the Soviet Union.
• May 30 – Mariner program: Mariner 9 is launched toward Mars.
• June 30 – The crew of the Soyuz 11 spacecraft are killed when their air supply leaks out through a faulty valve during re-entry preparations, the only human deaths to occur outside Earth's atmosphere.
• July 26 – Apollo program: Launch of Apollo 15. On July 31 the Apollo 15 astronauts become the first to ride in a lunar rover a day after landing on the surface.
• November 13 – Mariner program: Mariner 9 enters Mars orbit.

  Biology

• July – Francis G. Howarth discovers communities of specialized thermophile cave animals living in lava tubes at Hawaii Volcanoes National Park.
• C. A. W. Jeekel publishes Nomenclator Generum et Familiarum Diplopodorum.
• John O'Keefe discovers place cells in the mammalian brain.

  Computer science

• July 4 – Michael S. Hart posts the first e-book, a copy of the United States Declaration of Independence, on the University of Illinois at Urbana–Champaign's mainframe computer, the origin of Project Gutenberg.
• November 3 – The UNIX Programmer's Manual is published.
• November 15 – Intel release the world's first microprocessor, the 4004.
• Ray Tomlinson sends the first ARPAnet e-mail between host computers, at BBN, Cambridge, Massachusetts, with the first use of the @ sign in an address.
• Kenbak-1 goes on sale. It is considered by the Computer History Museum and the American Computer Museum to be the world's first personal computer.
• the earliest floppy disks, invented at IBM, which were 8 inches wide and long, commercially available by 1971
• Computer Space is released. The first arcade video game.

  Conservation

• February 2 – The international Ramsar Convention for the conservation and sustainable utilization of wetlands is signed in Ramsar, Mazandaran, Iran.

  Earth sciences

• February 9 – The San Fernando earthquake occurred in southern California with a magnitude of 6.6 and a perceived intensity of XI on the Modified Mercalli Intensity scale.

  Mathematics

• Stephen Cook and John Hopcroft introduce the concept of NP-completeness in computational complexity theory at the 3rd Annual ACM Symposium on Theory of Computing.
• Daniel Quillen publishes a proof of the Adams conjecture.
• Steven Takiff introduces Takiff algebras.

  Medicine

• October 1 – Godfrey Hounsfield's invention, X-ray computed tomography, is first used on a patient with a cerebral cyst at Atkinson Morley Hospital in Wimbledon, London.
• Boston Women's Health Book Collective publishes Our Bodies, Ourselves in the U.S.
• E. G. L. Bywaters characterises adult-onset Still's disease, a rare form of inflammatory arthritis.
• Smallpox is eradicated from the Americas.

  Physics

• Roger Penrose proposes the Penrose process.

  Psychology

• August 14–20 – Stanford prison experiment.
• Konrad Lorenz publishes Studies in Animal and Human Behavior, Volume II.

  Technology

• Richard H. Frenkiel, Joel S. Engel and Philip T. Porter of Bell Labs in the United States set out the parameters for a practical cellular telephone network.
• J. J. Stiffler publishes his book Theory of Synchronous Communications and edits a special issue of IEEE Transactions on Communication Technology on error correction codes.

  Institutions

• Paris Descartes University begins to function in continuation of the medical department of the University of Paris.

  Awards

• Nobel Prizes
• * Physics – Dennis Gabor
• * Chemistry – Gerhard Herzberg
• * Medicine – Earl W Sutherland, Jr
• Turing Award – John McCarthy

  Births

• May 29 – Howard Gobioff, American computer scientist.
• June 28 – Elon Musk, South African-born Canadian-American entrepreneur, engineer, inventor and investor.
• July 4 – Sivakumar Veerasamy, Indian plant geneticist.
• August 2 – Ruth Lawrence, English-born mathematician.

  Deaths

• January 25 – Donald Winnicott, English child psychiatrist.
• February 16 – Heinrich Willi, Swiss pediatrician.
• March 11 – Philo T. Farnsworth, American television pioneer.
• April 1 – Dame Kathleen Lonsdale, Irish-born crystallographer.
• April 6 – Margaret Newton, Canadian plant pathologist.
• June 6 – Edward Andrade, English physicist.
• June 30 – Soviet cosmonauts
• * Georgy Dobrovolsky
• * Vladislav Volkov
• * Viktor Patsayev