the course of its 33 missions. Because the shuttle sometimes flew crew members arriving and departing Mir and the ISS, not all of them launched and landed on Atlantis. Astronaut Clayton Anderson, ESA astronaut Leopold Eyharts and Russian cosmonauts Nikolai Budarin and Anatoly Solovyev only launched on Atlantis. Similarly, astronauts Daniel Tani and Sunita Williams, as well as cosmonauts Vladimir Dezhurov and Gennady Strekalov only landed with Atlantis. Only 146 men and women both launched and landed aboard Atlantis. Some of those people flew with Atlantis more than once. Taking them into account, 203 total seats were filled over Atlantis 33 missions. Astronaut Jerry Ross holds the record for the most flights aboard Atlantis at five. Astronaut Rodolfo Neri Vela who flew aboard Atlantis on STS-61-B mission in 1985 is the only Mexican to have traveled to space. ESA astronaut Dirk Frimout who flew on STS-45 as a payload specialist was the first Belgian in space. STS-46 mission specialist Claude Nicollier was the first astronaut from Switzerland. On the same flight, astronaut Franco Malerba became the first citizen of Italy to travel to space. Astronaut Mike Massimino who flew on STS-125 mission became the first person to use Twitter in space in May 2009. Having flown aboard Atlantis as part of the STS-132 crew in May 2010 and Discovery as part of the STS-133 crew in February/March 2011, Stephen Bowen became the first NASA astronaut to be launched on consecutive missions. Flights listing Problems Composite overwrapped pressure vessels NASA announced in 2007 that 24 helium and nitrogen gas tanks in Atlantis were older than their designed lifetime. These composite overwrapped pressure vessels (COPV) were designed for a 10-year life and later cleared for an additional 10 years; they exceeded this life in 2005. NASA said it could not guarantee any longer that the vessels on Atlantis would not burst or explode under full pressure. Failure of these tanks could have damaged parts of the orbiter and even wound or kill ground personnel. An in-flight failure of a pressure vessel could have even resulted in the loss of the orbiter and its crew. NASA analyses originally assumed that the vessels would leak before they burst, but new tests showed that they could in fact burst before leaking. Because the original vendor was no longer in business, and a new manufacturer could not be qualified before 2010, when the shuttles were scheduled