On Dec. 3, 1985, Army astronaut mission specialist Lt. Col. Sherwood "Woody" Spring and the crew of STS 61-B Atlantis concluded their seven-day flight by landing at Edwards Air Force Base, California.

During this flight, the STS 61-B crew, which included the first Mexican astronaut, payload specialist Dr. Rodolfo Neri Vela, conducted a variety of life science experiments, photographed the earth for a geologic study, deployed three communications satellites and experimented with concepts for assembling structures in space.

Spring was responsible for the satellite deployment and participated in the extra vehicle activities, or EVAs, with Air Force Maj. Jerry Ross to construct and dismantle two separate structures.

The satellites were deployed during the first three days of the mission. On the first day, Spring launched the Morelos-B into a geosynchronous orbit. This Mexican communications satellite provides telephone, television and wireless services for Mexico.

The second satellite, deployed on the second day, Thanksgiving Day, was the Aussat II, an Australian communications satellite. The Aussat was designed to improve maritime and air traffic control communications, as well as relaying digital data, telephone and satellite television across the Australian continent.

Ross meanwhile oversaw the deployment of the RCA Satcom K-2 communications satellite on the crew's third day in space.

With the payload bay clear, Spring and Ross were ready to begin their next assignment - two construction experiments to test the feasibility of assembling large structures in space and practicing space station maintenance scenarios.

On Nov. 29, Spring and Ross initiated the Experimental Assembly of Structures in Extravehicular Activity, or EASE, and Assembly Concept for Construction of Erectable Space Structures, or ACCESS, experiments.

In these two EVAs, or spacewalks, the two mission specialists attached beams, nodes and struts to assemble "tinker-toy like structures." In this first attempt to construct large structures in space no tools were required.

The EASE project involved six 12-foot aluminum beams with identical nodal joints designed to create an inverted tetrahedron or pyramid. To create this design, the two astronauts were required to maneuver around the structure simulating space station construction with both foot restraints and the remote manipulator system.

The ACCESS project conducted two days later meanwhile involved 93 tubular aluminum struts of different lengths and with varied joint nodes. The goal was to assemble and dismantle a 45-foot truss to assess concepts related to large scale construction in space.

At the same time, this experiment would hopefully validate "ground-based timelines established by neutral buoyancy water simulations at the Marshall Space Flight Center" in Huntsville, Alabama.

To assess learning and productivity, as well as the "EVA dynamics human factors in construction," both the EASE and ACCESS projects were assembled and dissembled multiple times during the spacewalks.

The second EVA also addressed anticipated maintenance tasks for the space station with such scheduled tasks as stringing electrical cable; removing and replacing struts and nodes; and manipulating the completed framework itself. Together, Spring and Ross successfully completed two spacewalks lasting five hours and 32 minutes, and six hours and 38 minutes respectively.

With these experiments, the crew of STS 61-B helped establish the concepts and procedures which would support the development of the International Space Station.