|Profile: Khalid Alshibli||
Excitement born of commitment can be infectious. When project scientist for the Mechanics of Granular Materials (MGM) experiment, Khalid Alshibli, invites undergraduate students to work with him, his enthusiasm rubs off. "I have many of them come to work with me for just one day. At first, they say, 'Well, I'm just trying to finish my undergraduate degree and go and find a job.' But once students know more about all we are doing and that we are conducting experiments on the space shuttle, they really become very excited," Alshibli recounts. "They work with me for one or two semesters, and then most of them stay with us for a graduate degree."
A professor of geotechnical engineering (civil engineering applied to soil and building foundations) at Louisiana State University and Southern University, both in Baton Rouge, Alshibli has been working with MGM for 10 years now. He started as a doctoral research assistant at the University of Colorado, Boulder, under MGM Principal Investigator (PI) Stein Sture. Alshibli was fascinated by the research because "Soil liquefaction has been haunting us here on Earth," he explains. "Every time an earthquake hits an area with sand deposits under a groundwater table such as the west coast of the United States, the sand liquefies [behaves like quicksand]. Once the sand liquefies, you have sinkholes and boiling sand, which result in devastating damage for all structures in these areas."
As a doctoral student, Alshibli wanted to understand what happens when soil liquefies, and Sture was headed for low Earth orbit to find answers. "In the lab," Alshibli says, "we can make the soil liquefy, but gravity collapses the soil in maybe 2, 3 seconds" - not enough time to measure the soil properties. In orbit, the effects of gravity are minimized "so we could study liquefaction and get good measurements."
After earning his doctorate, Alshibli wanted to continue working with MGM. "I moved to Huntsville, Alabama, in 1995 to establish a testing lab for our experiment at Marshall [Space Flight Center]," he recalls. From 1995 to 1998, he worked as a research associate for the PI as well as for the project scientist at that time, Marshall employee Nicholas Costes. When Costes retired in August 1998, Alshibli himself became project scientist. Alshibli says of the change, "I'm doing more supervising right now rather than doing the [scientific] trench work."
Under Alshibli's supervision, MGM flew on Space Shuttle Columbia for mission STS-107 in January 2003. The crew, as well as most of the experiments onboard the science-dedicated flight, perished on February 1, 2003, when the space shuttle broke apart during its re-entry into Earth's atmosphere.
For the week and a half before the tragedy, however, Payload Commander Michael Anderson, Mission Specialist Kalpana Chawla, and other crew members conducted dozens of biological and physical sciences investigations. For the MGM experiment, Anderson and Chawla used a new procedure developed by the MGM project team to reform (recycle) soil specimens. The experiment involved compressing a cylinder of wet sand while maintaining control of water pressure inside and around the sand specimen. "In the past on every mission we flew three test cells, and once we compressed a specimen, that was it - we could not get more science out of it," Alshibli explains. "In the STS-107 mission, we employed a new technique, so after we tested the specimen and compressed it, we could reform it and conduct more experiments."
Working with Anderson and Chawla was the MGM project team on the ground, using new flight hardware that could be controlled from Earth. "We had a live uplink," says Alshibli, so the experiment required only minimal time from the space shuttle crew, compared to older hardware used for STS-79 in 1996 and for STS-89 in 1998. "In flight, we were able to trigger or reproduce liquefaction, and the liquefied sand specimen did not collapse in space. We were very successful."
The ground team also had a live downlink of data and results. "We acquired data once every 10 seconds from nine out of 10 experiments, about 40-50 percent of all the MGM data recorded onboard," explains Alshibli. Data cards onboard the space shuttle downloaded all data once a second, but the cards were lost in the accident. "Now we are filtering the data of any anomalies caused by signal interference during data transmission from Columbia to Johnson Space Center, and then analyzing the filtered data."
Alshibli attributes the fact that there are any data to analyze at all largely to the Columbia crew. "Mike [Anderson] and KC [Kalpana Chawla] were part of a very special crew. On day 10, they were off duty, but they decided to work anyway to catch up on some of the science that had been missed. They were very dedicated."
So is Alshibli. New developments such as the telemetry-controlled hardware and the hope of applying future MGM findings toward safer building designs keep him committed to the research and the work for which the crew of the Columbia made such a great sacrifice. "The seven crew members are irreplaceable," he reflects. "We had some minor setbacks in losing MGM experiment data, but the loss of the crew will affect the rest of my life."
He adds, "There is risk in everything we do in life. The Columbia tragedy should not cause us to retreat - I hope that we will soon be ready to explore again and push the envelope of knowledge further."
Julie Moberly - http://spaceresearch.nasa.gov