STS-121 was a 2006 NASA Space Shuttle mission to the International Space Station (ISS) flown by Space Shuttle " Discovery".
 The main purposes of the mission were to test new safety and repair techniques introduced following the "Columbia" disaster of February 2003 as well as to deliver supplies, equipment and European Space Agency (ESA) astronaut Thomas Reiter from Germany to the ISS.
The European Astronaut Corps is a unit of the European Space Agency (ESA) that selects, trains, and provides astronauts as crew members on U.S. and Russian space missions.
 As of Nov 2014, 24 ESA astronauts are now able to go board the ISS.
 There are currently 47 members of the Corps, 26 currently active.
 The European Astronaut Corps is based at the European Astronaut Centre in Cologne, Germany.
 They can be assigned to various projects both in Europe (at ESTEC, for instance) or elsewhere in the world, at NASA Johnson Space Center or Star City.
Thomas Arthur Reiter (born 23 May 1958 in Frankfurt, West Germany) is a retired European astronaut and is a Brigadier General in the German Air Force currently working as ESA Interagency Coordinator and Advisor to the Director General at the European Space Agency (ESA).
 He was one of the top 25 astronauts in terms of total time in space.
 With his wife and two sons he lives near Oldenburg in Lower Saxony.
Interbol (Russian: Интербол ) is an international space project under the leadership of the Russian Space Agency and the Space Research Institute of the Russian Academy of Sciences.
 The list of participants includes the Institute of Atmospheric Research of the Czech Academy of Sciences, NASA, European Space Agency, Japan Aerospace Exploration Agency, and the Canadian Space Agency.
 The goal of the project is to study the correlations between plasma processes in the tail of the magnetosphere and in the Van Allen radiation belt (auroral particles acceleration region) with a high time-space resolution.
 Two space probes have been launched into high-altitude elliptical orbits:
The Director General of the European Space Agency is the highest-ranked official of the European Space Agency (ESA), a space agency formed by the collaboration of prominent European nations.
The Austrian Space Agency, since 2005 officially Aeronautics and Space Agency (German: Agentur für Luft- und Raumfahrt) is an organization whose purpose is to coordinate Austrian space exploration-related activities, both national programs and European Space Agency related programs.
 It was established in 1972 in Vienna.
 In 1987, Austria became a member state of the European Space Agency.
Claude Nicollier (born 2 September 1944 in Vevey, Switzerland) is the first astronaut from Switzerland.
 He has flown on four Space Shuttle missions.
 His first spaceflight (STS-46) was in 1992, and his final spaceflight (STS-103) was in 1999.
 He took part in two servicing missions to the Hubble Space Telescope (called STS-61 and STS-103).
 During his final spaceflight he participated in a spacewalk, becoming the first European Space Agency astronaut to do so during a Space Shuttle mission (previous ESA astronauts conducted spacewalks aboard "Mir", see List of spacewalks and moonwalks 1965–1999).
 In 2000 he was assigned to the Astronaut Office Extravehicular Activity Branch, while maintaining a position as Lead ESA Astronaut in Houston.
 Nicollier retired from ESA in April 2007.
The Nationalist Movement is a Mississippi-founded, white nationalist organization with headquarters in Georgia that advocates what it calls a "pro-majority" position.
 It has been called white supremacist by the Associated Press and Anti-Defamation League, among others.
 Richard Barrett was succeeded by unanimous vote as leader by Thomas Reiter after Barrett's murder.
 Its Secretary originally was Barry Hackney, and the position of Secretary was discontinued by Thomas Reiter.
 Thomas Reiter saved most Nationalist Movement assets and intellectual property after Barrett's murder.
 The symbol of the movement is the Crosstar.
 In 2012 with the endorsement of Thomas Reiter, Travis Golie was sworn in as the Leader of The Nationalist Movement.
 Like Reiter, Golie was an original Barrett-era Nationalist Movement member.
 Golie returned The Nationalist Movement headquarters to the South where it originated.
Jean-François André Clervoy (born 19 November 1958) is a French engineer and a CNES and ESA astronaut.
 He is a veteran of three NASA Space Shuttle missions.
The Hubble European Space Agency Information Centre (HEIC) is a science communication office, established at the Space Telescope - European Coordinating Facility (ST-ECF) in Munich, Germany late in 1999.
 This initiative was taken so as to fulfil the NASA/ESA Hubble Space Telescope (HST) outreach and education tasks for the European Space Agency (ESA), as outlined in an agreement between NASA and ESA.

Question: Which of the two European Space Agency astronauts, Jean-François Clervoy and Thomas Reiter, has participated in missions with NASA?
Answer: Jean-François André Clervoy