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Mission or Study ID:   STS-121
Shuttle Program
Launch/Start Date:
Landing/End Date:
13 days
STS-121 Crew Patch

STS-121, International Space Station (ISS) Assembly Flight ULF1.1, is the 18th assembly flight to the station. The crew consists of Commander Steve Lindsey, Pilot Mark Kelly, Mission Specialists Mike Fossum, Lisa Nowak, Stephanie Wilson, and Piers Sellers. Discovery will also bring a third Expedition crewmember to the station, European Space Agency (ESA) Flight Engineer Thomas Reiter. This will be the first three-person crew since the Expedition Six crew returned to Earth May 4, 2003. Without the Space Shuttle to ferry equipment to the station after the Columbia accident, only two people could be supported on board until the necessary provisions were in place. Reiter is the first ESA long-duration space station crewmember and will remain on board for six to seven months to work with the Expedition Thirteen and Expedition Fourteen crews. Reiter will remain return with the STS-116 Space Shuttle or a Soyuz mission.

Utility Logistics Flight (ULF 1.1) is primarily an ISS crew augmentation mission (a third crewmember will arrive on this flight), with the Leonardao Multi-Purpose Logistics Module (MPLM) ferrying more than 5,000 pounds of cargo, a majority of which is food, clothing, and crew consumables. The MPLM will carry two new research facilities; Minus Eighty-degree Laboratory Freezer for ISS (MELFI) and European Modular Cultivation System (EMCS), which will be installed in the Destiny laboratory. The MELFI will provide current and future ISS crews with a critical lab freezer capability for maintaining scientific samples and experiments. The EMCS, a ½ EXPRESS rack, is a large incubator that provides control over atmosphere, lighting, and humidity of growth chambers. The MPLM will also transport the Oxygen Generation System (OGS) rack that uses water to generate breathable oxygen for crewmembers. The life-support system is considered a test initiative for future long-duration missions to the moon and Mars. The MPLM will also carry a new cycle ergometer, which will give expedition crews on station better aerobic and cardiovascular conditioning through cycling activities.

The STS-121 and Expedition Thirteen crews will work together to accomplish two spacewalks. They will focus on Shuttle thermal protection system repair techniques and space station assembly and repair tasks. A third spacewalk also will be conducted if mission managers determine the Shuttle has enough consumables for an extra day for the mission. The third spacewalk would include tests of techniques for inspecting and repairing the orbiter's heat shield, the reinforced carbon-carbon (RCC) segments that protect the orbiter's nose cone and wing leading edges.

Several Detailed Supplementary Objectives (DSOs) will also be flown during the STS-121 mission. DSOs are space and life sciences investigations. Their purpose is to determine the extent of physiological deconditioning resulting from space flight, test countermeasures to those changes, and characterize the environment of the Space Shuttle and/or space station relative to crew health. DSOs being performed during this mission are:

  • Bioavailability and Performance Effects of Promethazine During Space Flight
  • Chromosomal Aberrations in Blood Lymphocytes of Astronauts
  • Eye Movements and Motion Perception Induced by Off-Vertical Axis Rotation (OVAR) at Small Angles of Tilt After Spaceflight
  • Monitoring Latent Virus Reactivation and Shedding in Astronauts
  • Sleep-Wake Actigraphy and Light Exposure During Spaceflight
  • Space Flight and Immune Function
  • Space Flight Induced Reactivation of Epstein-Barr Virus
  • Spatial Reorientation of Sensorimotor Balance Control in Altered Gravity

Space Shuttle Discovery returned to Kennedy Space Center in Florida on July 17th bringing STS-121 to an end. This flight was the orbiter's 32nd mission and the 115th in the Shuttle program's history.

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