The first major objective of the mission will be to retrieve the Space Flyer Unit (SFU), a reusable, free-flying platform of microgravity experiments, which was launched aboard a Japanese H-2 rocket on March 18, 1995. It was designed to be retrieved by the Space Shuttle.

The other principal goal of the flight will be the deployment, on-orbit operation and retrieval of the Office of Aeronautics and Space Technology-Flyer (OAST- Flyer). Carried by the Spartan free-flyer, the OAST-Flyer payload of four technology experiments will operate on orbit approximately 50 hours before its retrieval and stowage in Endeavour’s cargo bay.

Two Extravehicular Activities (EVAs) or spacewalks involving a total of three crew members will be conducted to prepare for the orbital construction and maintenance of the international space station. The EVAs are designed for the evaluation of techniques, tools and other equipment required for building the space station. They also will add to the spacewalking experience of the astronaut corps, and help to refine ground training methods for EVAs.

Other objectives of the nine-day mission include a variety of secondary experiments involving crystal growth, measurement of atmospheric ozone, remote sensing, and biological processes.

On its 10th flight, Endeavour will ascend to an orbital insertion altitude of 250 nautical miles (463 kilometers/288 statute miles) at a 28.45 inclination to the equator. The orbit will be lowered to 164 nautical miles (304 kilometers/189 statute miles) on Flight Day 3 to prepare for the deploy of the OAST-Flyer the following day.

The 74th Space Shuttle mission will begin with an early-morning liftoff in darkness from Pad B, Launch Complex 39. It is scheduled to end with a night touchdown on KSC’s Shuttle Landing Facility.

Two experienced space flyers and four rookies comprise the crew.

Commander Brian Duffy (Col., USAF) will have overall responsibility for success of the mission. He flew twice before, as the pilot on STS-45 in 1992 and on STS- 57 in 1993.

He will be assisted at the flight controls by Pilot Brent W. Jett Jr. (Lt. Cmdr., USN), who is making his first Shuttle flight. Jett has responsibility for rendezvous operations.

Of the four mission specialists, Leroy Chiao is the only one with previous spaceflight experience. He flew once before, as a mission specialist on STS-65 in 1994. He has a doctorate in chemical engineering.

Winston E. Scott (Capt., USN), a former Navy research and development project pilot, will be flight engineer on STS-72, and has prime responsibility for the SFU and OAST-Flyer systems.

Daniel T. Barry (M.D.) has doctorates in electrical engineering/computer science and medicine. Barry, Chiao and Scott will perform the spacewalks.

Koichi Wakata is from the Japanese Space Agency (NASDA). A former structural engineer, he will be the prime operator of the Remote Manipulator System (RMS) robotic arm for the deploy of the OAST-Flyer and the retrieval of both satellites.

For the first two days of the mission, Endeavour’s engines will be fired periodically to place it within 8 nautical miles of SFU for the final phase of the rendezvous and capture on Flight Day 3.

Endeavour will approach SFU from underneath the hexagonal-shaped, nearly four-ton satellite which will have its solar panels in the retracted position. From controls inside the orbiter, Wakata will move the mechanical arm to grab onto the satellite and berth it in the orbiter’s payload bay for the return trip to Earth.

SFU includes eight modules, two with avionics and other equipment, and six containing payloads such as an infrared telescope and an experiment on the effects of microgravity on egg spawning of Japanese red-bellied newts.

On Flight Day 4, Wakata is scheduled to deploy the OAST-Flyer using the RMS arm held high above the payload bay. Firings of Endeavour’s engines will be used to maintain a distance of as much as 90 nautical miles (167 kilometers) between the orbiter and the spacecraft which will operate as a free-flyer for up to 50 hours. Endeavour will then use the same underneath approach as it used with SFU to place itself in position for retrieval of the OAST-Flyer with the RMS arm on Flight Day 6.

The OAST-Flyer experiments are mounted on the rectangular, reusable Spartan Program satellite, which has flown six times before. Commonly used as a platform for astronomy instruments, the Spartan spacecraft this time will carry the following four technology experiments.

The Return Flux Experiment (REFLEX) is designed to determine the accuracy of computer-generated models of contamination of spacecraft. It will investigate the phenomenon of return flux that occurs when spacecraft give off tiny particles of dirt in the atmosphere which then collide with other particles and bounce back to the spacecraft. This dirt can cause the failure of spacecraft systems. REFLEX also will study the erosion of spacecraft surface coatings.

The Global Positioning System (GPS) Attitude Determination and Control Experiment or GADACS will demonstrate the use of GPS technology in space, this time to determine the attitude, location and velocity of the Spartan spacecraft. This will be the first time a spacecraft is controlled using GPS. The technology could lead to spacecraft redesign and lighter, less costly missions in the future.

The Solar Exposure to Laser Ordnance Device (SELODE) experiment will use a laser pulse traveling through a fiber optic cable to trigger an explosive charge in a new type of pyrotechnic device. This would eliminate concerns of accidental firing from stray electrical energy sources such radio transmitter signals or static electricity. Pyrotechnic devices have numerous applications on space vehicles such as separating the orbiter from the external tank approximately 8 minutes after launch.

The Spartan Packet Radio Experiment (SPRE) is an amateur radio (HAM radio) communications experiment. Its primary goal is to test satellite tracking using amateur packet radio and the GPS system. Although the Spartan carrier normally has no communications with the ground or the Shuttle on orbit, SPRE will be tested as a method of communications with the REFLEX experiment.

Two 6 1/2-hour spacewalks will be performed on the days after the deploy and retrieval of the OAST-Flyer. On Flight Day 5, as the OAST-Flyer experiments are gathering data while orbiting the Earth, Chiao and Barry will don Extravehicular Mobility Unit (EMU) spacesuits to enter the open payload bay. They are scheduled to evaluate a new EVA work station; a movable stanchion that provides stability for astronauts and holders for tools; a flexible foot restraint; and installation of a rigid umbilical that may be used on the international space station to hold fluid and electrical umbilicals in place. Scott will serve as coordinator of the EVA from inside the crew cabin, and Jett and Wakata will operate the RMS.

On Flight Day 7, after both SFU and the OAST- Flyer are safely berthed in the cargo bay, Chiao and Scott are scheduled to conduct the second spacewalk. During this EVA, they will evaluate a space station utility box designed to hold avionics and fluid line connections on the space station; an on-orbit-installed slidewire to which tethers can be connected; thermal improvements to spacesuits; and a wrist-mounted computer called the Electronic Cuff Checklist. They also will take measurements of the forces induced by spacewalking work. Barry will coordinate the second EVA from inside Endeavour, while Jett and Wakata operate the RMS.

Also in the payload bay will be the Shuttle Solar Backscatter Ultraviolet (SSBUV) instrument, which is scheduled to make its eighth and last flight aboard STS- 72. SSBUV measures ozone concentrations by comparing solar ultraviolet radiation with radiation scattered back from Earth’s atmosphere.

The Shuttle Laser Altimeter-01/Get Away Special (SLA-01/GAS) payload also is installed in the cargo bay. STS-72 will be the first of four planned remote sensing flights using SLA to precisely measure the distance between the Earth’s surface and the Space Shuttle. It will acquire samples of land topography and vegetation data, as well as provide an engineering test bed for future spaceflight laser sensors. Other parts of that payload include experiments in protein crystal growth, thermal energy storage and the behavior of flexible cantilevered beams in microgravity.

In-cabin payloads will include two collaborative projects between NASA and the National Institutes of Health (NIH). One will examine the early development of newborn rats and the other will study the effects of spaceflight on muscle and bone cells from chicken embryos.

Other in-cabin payloads are Protein Crystal Growth, which will introduce an enhanced version of vapor diffusion apparatus used in more than 20 previous Shuttle experiments; and the Commercial Protein Crystal Growth-8 (CPCG-8), which will process a new form of recombinant human insulin.