Crew members conducted experiments aimed at understanding bone tissue loss and the effects of microgravity on sensory perception. Two neurovestibular experiments investigating space motion sickness and perception changes were performed on the 2nd day as well. Astronauts Lucid and Fettman wore a headset, called an Accelerometer recording Unit, designed to continually record head movements throughout the day.
Only one minor issue came up on Tuesday, October 19, 1993 associated with a circuit breaker that tripped, cutting off power temporarily to one of the rodent cages in the module. Flight controllers in Houston reported it was not caused by a short in the electrical system and the breaker was reset, restoring power to the cage.
McArthur and Blaha began using the Lower Body Negative Pressure device on flight day 3, which is being tested as a countermeasure for the detrimental effects of microgravity. All three flight crew members will collect urine and saliva samples and keep logs of their exercise and food and fluid intake as part of the Energy Utilization detailed supplementary objective. DSO 612 looks at the nutritial and energy requirements of crew members on long-duration space flights and the relationship between fluid and food consumption.
On Wednesday, October 20, though the space toilet is working fine, the crew detected a slight leak around the filter door before going to bed. They removed the filter and cleaned up about a teaspoon of water -- much less than had been expected. As a precaution, a secondary fan separator unit was used to separate fluid from the air before cycling the air back into the cabin through the filter.
On Thursday, October 21, Payload Commander Rhea Seddon, Mission Specialists Shannon Lucid and David Wolf and Payload Specialist Martin Fettman collected additional blood and urine samples for the series of metabolic experiments. Some of the samples will follow-up on the calcium absorption experiment performed yesterday. The experiment, sponsored by Dr. C.D. Arnaud of the University of California at San Francisco, studies the mechanisms of how calcium is maintained and used in bone metabolism in space. Based on preliminary results from the 1991 SLS-1 mission, Dr. Arnaud believes the decrease in bone density is due to increased bone breakdown that is not compensated for by a subsequent increase in bone formation.
On Friday, October 22, 1993, using the on-board ham radio called SAREX for Shuttle Amateur Radio Experiment, Blaha and Searfoss contacted school children at the Sycamore Middle School in Pleasant View, Tennessee, and Gardendale Elementary in Pasadena, Texas. The Standard Interface Rack, or SIR, was tested today by Searfoss to demonstrate that equipment can be removed from one rack location and reintegrated into another by a single crew member during orbital operations while maintaining reliable mechanical, data and power interfaces.
Another new test flying aboard Columbia is a laptop computer simulator that is being flown to see if it will qualify as a tool for helping the mission commander and pilot maintain their proficiency for approach and landing during longer duration Space Shuttle flights. The laptop is controlled using a joy stick hand controller similar to the one used to fly the orbiter in the final minutes before landing.
On Saturday, the payload crew members will devote much of their time to metabolic studies of the 48 rodents on board the Spacelab science workshop. Payload commander Rhea Seddon, and crewmates David Wolf, Shannon Lucid and veterinarian Marty Fettman are scheduled to draw blood from the tails of some of the rodents, then inject a special isotope into the rodents to measure the volume of their plasma. Another blood draw will follow, to measure how weightlessness may be affecting the red blood cell count of the animals.
After several ham radio contacts around the country and work in a vacuum bag designed to ease the body's readaptation to Earth's environment, the orbiter crew made up of Commander John Blaha, Pilot Richard Searfoss and Mission Specialist William McArthur oversaw a short firing of one of the orbital maneuvering system engines to drop the low end of Columbia's orbit from 150 to 142 nautical miles (278 to 263 km) to increase the landing opportunities should the mission be extended for weather or a system problem that would keep the crew in orbit two extra days.
On Wednesday, October 27, 1993, Pilot Rick Searfoss put Columbia through some maneuvers as part of the Orbital Acceleration Research Experiment. The main goal of the experiment is to accurately measure the aerodynamic forces that act on the shuttle in orbit and during the early stages of entry. The information will be useful to scientists and engineers planning future Spacelab microgravity research flights in which experiments will need a quiet, motion- free environment to produce the best possible data.
On Thursday, October 28, 1993, After enjoying a half a day off, the astronauts aboard Columbia continued to collect scientific data on how humans and animals adapt to the absence of Earth's gravity.
Payload Commander Rhea Seddon sent down a special message to her husband, Astronaut Office Chief Robert L. Gibson when she surpassed his total of 632 hours, 56 minutes in space. "He's still a really good guy, I still love him a lot, but I've got more hours in space than he does, so there!" she teased. Seddon acknowledged, however, that he has more launches and landings, having flown four times to her three.
Pilot Rick Searfoss took time out from snapping some infrared photography of the wildfires burning in southern California to say that the crew's thoughts are with the firefighters working to quell the flames and the residents whose homes are being threatened. He said he hoped the fires would be brought under control soon, and added that the photographs he was taking will be among some 4,000 frames that will be returned to Earth for meteorologists, geologists, ecologists and archeologists to study after the flight.