The primary objective of this International Space Station (ISS) assembly flight, designated as 9A, was the delivery and installation of the S-1 Truss, the second piece of the station's 11-piece Integrated Truss Structure, which will eventually span 110 meters (360 feet). The S1 Truss, which is 13.7 meters (45 feet) long and weighs 13.6 metric tons, was attached to the starboard end of the S-Zero (S0) Truss by collaborative efforts between the Expedition Five crew who operated the station's robotic arm, Canadarm2, and the Shuttle crewmembers, Wolf and Piers, who performed three spacewalks to complete the installation. The truss expands the station's railroad and contains an S-Band communications system and a new external cooling system for the station. Also, the Crew and Equipment Translation Aid (CETA), a mobile work platform, was mounted on the S1. The next piece of Integrated Truss Structure will be added to the station during STS-113 in November.
Three new experiments and fresh supplies to continue research already under way on the ISS during the Expedition Five mission were launched on STS-112: the Commercial Generic Bioprocessing Apparatus (CGBA), which will carry out investigations on the behavior of renal cortical cells and infectious agents in the space-flight environment; the Plant Growth Bioprocessing Apparatus (PGBA), which will investigate the effects of microgravity on plants by testing the hypothesis that metabolic pathways are altered, resulting in differing ratios of materials normally devoted to structural integrity of the plant; and the Protein Crystal Growth Single-locker Thermal Enclosure System (PCG-STES), which will provide a temperature controlled environment for growing high-quality protein crystals in microgravity for analyses on the ground to determine the protein's structure.
Several Detailed Supplementary Objectives (DSOs) were also performed during the STS-112 mission. A DSO is a NASA-sponsored investigation performed by Space Shuttle crewmembers, who serve as the test subjects. These studies are designed to require minimal crew time, power and stowage. Biomedical DSOs focus on operational concerns, including space motion sickness, cardiovascular deconditioning, muscle loss, changes in coordination and balance strategies, radiation exposure, pharmacokinetics and changes in the body's biochemistry.
Development Test Objectives (DTO) performed during this mission included Space Station RMS Dynamic Model Validation, Single-String Global Positioning System, and Crosswind Landing Performance. A DTO is a NASA-sponsored investigation that is performed by Space Shuttle crewmembers to evaluate new hardware and procedures involving the Orbiter, its subsystems, and its support equipment.
Additional experiments included SHIMMER, an investigation designed to identify possible ozone loss in Earth's atmosphere, and Ram Burn Observations (RAMBO), a Department of Defense experiment in which the Shuttle Orbital Maneuvering System engine burns were observed for the purpose of improving plume models.
Upon conclusion of the STS-112 mission, four completed ISS experiments (Advanced Astroculture, Protein Crystal Growth Single-locker Thermal Enclosure System, Microencapsulation Electrostatic Processing System, StelSys, and Zeolite Crystal Growth) were returned to Earth. The Shuttle Atlantis landed at Kennedy Space Center in Florida on October 18, 2002.