Opportunity, MER-B (Mars Exploration Rover – B), is a robotic rover on the planet Mars, active since 2004 and the remaining rover in NASA's ongoing Mars Exploration Rover Mission. Launched from Earth on July 7, 2003, it landed on Meridiani Planum on January 25, 2004 at 05:05 Ground UTC (about 13:15 local time). This is three weeks after its twin Spirit (MER-A) touched down on the other side of the planet. Its twin became immobile in 2009 and in 2010 ceased communications, but MER-B is still active as of 2012.

Mission highlights include completion of the 90 Sol (90 Martian days) mission, discovery of an extraterrestrial meteorite (Meridiani Planum), and over two years studying Victoria crater. It survived dust-storms in 2007 and reached Endeavour crater in 2011, which has been described as the equivalent of a "second landing site". After conducting stationary science in the bleak winter months, it began moving again in May 2012.

The Jet Propulsion Laboratory (JPL), a division of the California Institute of Technology in Pasadena, manages the Mars Exploration Rover project for NASA's Office of Space Science in Washington, D.C.

Maria Elizabeth Rothmann (M.E.R.) (28 August 1875 – 7 September 1975) was an Afrikaans writer, and co-founder of the Voortrekkers youth movement. Her unique contribution to Afrikaans literature was an ethical didactic, cultural historic review of a bygone Afrikaans society.

She was born in Swellendam, in the then Cape Colony. She was one of the first South African women to attend a university. She acquired a B.A.-degree at the South African college in Cape Town. At the age of 22 she started working as a teacher, first in Johannesburg, later in Grahamstown and eventually at Swellendam. On 18 September 1902, while in Grahamstown, she married Herbert Charles Gordon Oakshott, a school principal. From this marriage James Rothmann (later Jacobus or Koos) was born in 1903, and Anna in 1904. The couple reached a divorce on 4 July 1911.

M.E.R.'s writing career started in 1918 in the lowveld. She became involved with journalism – first at Die Boerevrou (1920 to 1922) in Pretoria, and afterwards at Die Burger (1922 to 1928) in Cape Town. She became the first woman editor of the latter. In 1928, she was appointed the organizing secretary of the A.C.V.V.. She traveled the country in this capacity, while investigating the question of poor whites.