Craig Kluever’s dream was born as he found himself awestruck in front of a grainy black-and-white television screen watching Apollo 11 land on the moon. He was in kindergarten. As he puts it, “that just made a big impact on me. Of course, the first thing I wanted to be was an astronaut.” Those early dreams of becoming an astronaut turned instead into a pursuit of the science behind the rockets. Today, the MU Professor of Mechanical and Aerospace Engineering works behind the scenes to solve the kind of problems involved in designing space travel—such as how to take off, how to reach a target, and, more importantly, how to return safely to Earth.
Craig Kluever’s childhood dream of becoming an astronaut turned instead into the pursuit of the science behind the rockets. Today, the Professor of Mechanical and Aerospace Engineering seeks to solve the kind of problems involved in space missions—like how to take off, and most importantly, how to return safely to Earth. Kluever came to this area of research in graduate school when he had a fellowship with NASA, developing computer programs to help solve problems involved with mission designs that use electric propulsion (as opposed to chemical propulsion). At the time, Kluever recalls, electric propulsion was a brand new technology, and NASA needed predictive computer models to calculate missions, for example to map a trajectory from Earth to Mars using electric propulsion.
The first space mission to use electric propulsion was Deep Space I. Launched in 1998, it was a test mission for electric propulsion, one on which a lot of people worked to see the mission to success. “It had a very modest target,” Kluever says – basically just to fly by an asteroid – “and it was able to complete that mission.” Since then there have been some very big plans to send spacecraft to Jupiter or other outer planets using electric propulsion. “But the problem with electric propulsion (and NASA) is that these technologies cycle,” observes Kluever. “Sometimes they’re politically in favor and sometimes not. Right now they’re out of favor,” largely due to budgetary restraints.
For the first six years as an assistant professor, Kluever primarily focused on space missions that used electric propulsion. He worked with NASA on a lot of feasibility studies—aka “paper studies” (e.g., missions to the moon, to Mars, to the outer planets, to Pluto), studies that go into rounds of proposals that compete for selection. Unfortunately, none of the studies Kluever worked on have been selected, though he has come close. He worked on Diana, an early version of Dawn, which did get selected. Kluever has also worked with the X-33 program. In this project he looked at the approach and landing guidance system for this unpowered vehicle, which would have been the next-generation space shuttle (if the program had not been cancelled). Now the hot topic is the Crew Exploration Vehicle, the capsule in which NASA hopes to send astronauts to the moon and to Mars. Kluever is focusing on the atmospheric phase of the entry guidance system, particularly the Earth return, and also working on the ascent guidance system for the vacuum-flight phase of the Crew Launch Vehicle.
The guidance system Kluever worked on for the X-33 shuttle was to have robustness built into its designs for guidance and control systems. Although the existing Shuttle works very well, Kluever says, “it does not have a lot of robustness built in.” If it comes in on a flight path that is too steep, too shallow, or too fast, it has very limited capabilities for altering that flight path and still making the planned approach for landing. “Fortunately the Shuttle hasn’t had any major mechanical failures (like a broken rudder) on the way down. But if failures occurred, it would have limited maneuverability.” Kluever’s contribution to this project will allow a new shuttle’s guidance system to not only maintain the exact amount of energy to reach the landing area, but also to recognize and steer toward the runway. “Robust” describes a new guidance system that is more automated and adaptable, and therefore, a new generation of safer shuttle vehicles – “so that if some major failure occurred—like the rudders didn’t work and it had limited banking ability, or the elevators didn’t work, and it had limited pitching capability—you could recalculate a trajectory that would still take it to a safe landing. That’s what’s meant by robustness.”
In the most basic definition of his field, Kluever explains that engineers apply math and science knowledge to real problems, taking existing knowledge from mathematics and the physical sciences to construct some real device or to make some system better. “What do engineers do at work?” he laughs irreverently, “they go to a lot of meetings, they work on projects, and they try to stay on budget!”
Asked why this research was important, Kluever responded in a surprising way. In an era of tight budgets, most researchers are accustomed to arguing for the importance of their work. However, Kluever answers ambivalently: “That’s the hardest question.” He could cite the many technological advances that were outcomes of the space program (from Teflon and computers to mammograms), advances that impact many lives. But that kind of response has become something of a cliché, he believes. Presently, roughly 75% of NASA’s budget is tied up in the Space Shuttle and the International Space Station, with only the remainder left to fund basic science, biological, earth science, and robotic missions (to Jupiter, Pluto, and Mercury). Whether there’s a direct benefit to human spaceflight, Kluever admits, “I myself struggle with that question. In this day of tight budgets, I’m not sure if that money is justified to send a person to the moon.”