The International Space Station (ISS) is a unique laboratory operating in low Earth orbit. Over the past 20 years, more than 3,000 research surveys have been conducted on board the orbiting facility in 108 countries. In the early days of the ISS assembly, research took place on a more modest level than today. Delays in launching Zvezda The service form as of July 2000 slipped the general sequence of the ISS assembly, including the arrival of the Destiny Laboratory module, the cornerstone of US research activities aboard the ISS, until February 2001
Left: the ISS as it appeared to the STS-106 crew in September 2000. Right: the STS-106 crew, front left to right, Malenchenko, Wilcutt and Altman; rear left to right, Burbank, Lu, Mastracchio and Morukov.
The STS-106 space shuttle mission took off on the morning of September 8, 2000, with the seven-person crew of Commander Terence W. Wilcutt, pilot Scott D. Altman, and mission specialists Edward T. Lu, Richard A. Mastracchio, Daniel C. Burbank, Yuri I. Malenchenko and Boris V. Morukov. The mission was dedicated to refueling and equipping the ISS prior to the arrival of the crew of the first expedition and therefore had little more time or space for scientific cargoes. To facilitate the integration process, the three chosen experiments all had previous experience of flying space shuttle missions, required little time for the crew, and used little of the stowage available on the climb. One of the experiments would remain in the shuttle’s center deck throughout the shuttle mission as a so-called sortie payload, a second required only for one crew member to transfer it to a quiescent position aboard the ISS, and the third was only passive stowage, pre-positioned on the ISS to be operated once the crew of Expedition 1 has arrived.
Left: Morukov leading the CGBA on the shuttle’s central deck. Middle: Wilcutt who runs the CGBA. Right: CGBA isothermal control module.
The sortie’s payload consisted of a Commercial Generic Bioprocessing Apparatus (CGBA), a single apparatus the size of a central locker that had flown multiple times on previous space shuttle flights. The CGBA, built by Bioserve Space Technologies at the University of Colorado at Boulder, provided automated processing for biological experiments, minimizing crew interactions with activation, periodic health checks, and deactivation. On STS-106, the CGBA contained the Isothermal Containment Module (ICM) to provide temperature control for the two experiments within the unit. An experiment, Synaptogenesis in Microgravity conducted by Principal Investigator (PI) Haig Kashishian of Yale University in New Haven, Connecticut, used seven Gas Exchange Group Activation Packages (GE-GAP) to host and control the development of Drosophila melanogasteror fruit flies. The ICM automatically controlled the GE-GAPs through a preset temperature profile during the mission. The experiment, previously performed on STS-93 in 1999, sought to better understand the development of the nervous system of fruit flies under conditions of microgravity. The second CGBA experiment, Kidney Cell Gene Expression led by PI Timothy G. Hammond of Durham Veterans Medical Center in Durham, North Carolina, used a single Generic Bioprocessing Apparatus (GBA) in the ICM. The aim of the experiment, previously performed on STS-90 in 1998, was to investigate how microgravity affects the gene expression of proteins in cultured kidney cells. The CGBA functioned normally throughout the flight, but unexpected temperature excursions in the two experiments made interpretation of the results problematic.
Left: Student preparing samples for the PCG-EGN Dewar experiment. Middle: still from a video of Lu transferring the PCG-EGN to the Zarya module. Right: PCG-EGN Dewar stowed in Zarya.
The first passive scientific experiment aboard the ISS was the nitrogen gas enhanced by protein crystal growth (PCG-EGN). Alexander McPherson of the University of California at Irvine was the PI for this experiment which had flown seven times during the Shuttle-Mir program. The day before launch, instantaneously frozen samples of 21 different protein solutions in capillary tubes provided by four researchers were loaded into the Dewar, a vacuum-packed container resembling a large thermos bottle with an absorbent liner saturated with liquid nitrogen. Middle and high school students from Alabama, California, Florida and Tennessee helped load about 150 of the 500 samples. The Dewar went into orbit on the shuttle’s central deck and, once the ISS hatches were opened, Lu moved the Dewar to a quiet location in the Zarya module. Over time, the liquid nitrogen dissolved, the frozen samples thawed, and the proteins crystallized out of solution. Without the disturbing influence of gravity, investigators hoped to grow larger, purer crystals to allow for a more detailed understanding of their structure. The Dewar was brought back to Earth from the next space shuttle mission to visit the ISS, STS-92, in October 2000, after spending 46 days in space. The PCG-EGN Dewar experiment subsequently flew four more times aboard the ISS.
Left: MACE-II experiment floating in Unity Node 1 module. Center: Shepherd using MACE-II in Unity during Expedition 1. Right: Helms operating MACE-II during Expedition 2.
The third experiment launched on STS-106 was the Middeck Active Control Experiment-II (MACE-II) led by PI R. Rory Ninneman of the US Air Force Research Laboratory in Albuquerque, New Mexico, with a collaborative team at Massachusetts Institute of Technology in Cambridge, Massachusetts, led by David W. Miller. The experiment, previously performed as MACE-I on STS-67 in 1995, sought to demonstrate algorithms that future satellites can use to reduce some stresses such as vibrations experienced during launch or during orbital maneuvers. The multibody platform test item, the structure of the MACE-II hardware that was tested, had four 1-inch diameter posts connected to five nodes. During operations, it was floating but loose in the form. The entire platform had 20 separate sensors that monitor vibrations. During STS-106, the MACE-II experiment launched as passive stowage in the Spacehab module and the crew transferred it to the Unit Node 1 module to await the arrival of the Expedition 1 crew. The crew commander, William M. Shepherd, operated MACE-II towards the end of his mission and as he was unable to complete all required sessions, the managers decided to leave it in orbit for the completion of Expedition 2 flight engineer Susan J. Helms experiment. The hardware returned to Earth aboard the STS-105 in August 2001.
The search for knowledge continues …