BRIAN J. CANTWELL William F. Durand Building STANFORD Edward C. Wells Professor 496 Lomita Mall AERONAUTICS & Chair, Department of Stanford University ASTRONAUTICS Aeronautics & Astronautics Stanford, CA 94305-4035

November 2004

Dear Aeronautics and Astronautics Alum,

Every year at this time I enjoy writing to you to highlight the events of the previous academic year in the Department of Aeronautics and Astronautics.

Department News Perhaps the most widely publicized event for the department this year was the launch of Gravity Probe B (GP-B) into a near perfect orbit on April 20 from Vandenberg Air Force Base. The purpose of GP-B is to test two unverified predictions of Einstein’s Theory of General Relativity. We want to evaluate how the mass of the Earth warps space and time and how its rotation twists space and time through an effect called “frame-dragging.” We believe that the latter result does occur, but there has never before been an experiment sensitive enough to measure it.

Conceived more than 45 years ago, the idea behind the experiment is straightforward. Place a gyroscope into orbit, with the spin axis pointed toward some distant star as a fixed reference point. With all external forces removed, the axis of spin should continue pointing at the star forever. But if the region of space through which the gyroscope moves is warped and slightly twisted, the axis of spin would slowly drift over time. By measuring the cumulative change in direction relative to the star, the small warping and tiny frame-dragging effects can be measured. The actual experiment requires exquisite accuracy. The axis of spin is predicted to drift only 0.042 arc-seconds per year due to frame-dragging. (An arc-second is 1/3600th of a degree.) To measure this angle change with an acceptable level of accuracy, GP-B needs to have a precision of 0.0005 arc-seconds per year. The gyroscope is a 1.5 inch-diameter fused quartz and silica sphere with a superconducting niobium coating. To make GP-B possible, several landmark developments had to occur, such as the development of the drag-free satellite concept and sensing techniques for measuring the change in position of the spin axis without interfering with the spin.

Over its lifetime this program has supported more than 100 Aero/Astro Ph.D. theses. Bob Cannon, Dan DeBra, and Brad Parkinson are the current Aero/Astro faculty who have been involved in the program over the years. Professor Francis Everitt (Applied Physics) has been the prime mover behind the experiments for more than four decades. When NASA began to put substantial funding into the program in the early 1990s, Brad became the program manager. Francis’ and Brad’s strong leadership is one of the major reasons for the success of the program thus far. We will know in 18 months if GP-B is successful. If it is, it will surely be viewed as one of the greatest experiments of the last century. Current news of the mission can be found at gravityprobeb.com.

(By the way, Gravity Probe A was launched in 1976. This sub-orbital flight of one hour and fifty-five minutes measured the effect of the Earth’s gravitational field on a very precise clock. The practical applications of Gravity Probe A results can be found on the

Phone: 650.723.4825 • Fax: 650.725.3377 • E-mail: [email protected] • Web: aa.stanford.edu clocks onboard the current constellation of GPS satellites. In order to keep them in synchronism with one another, corrections must be applied to the clocks.)

Graduation News and Awards We had a wonderful graduation celebration this year with 61 M.S. graduates, one Engineer’s degree graduate, and 18 Ph.D. graduates.

Professor Steve Rock received the Outstanding Teacher Award for the second time from the local student chapter of the AIAA.

Andre C. Marta received the AIAA best course assistant award.

Alexandre Bayen, Claire Tomlin’s Ph.D. student, won the William Ballhaus Award for the best Ph.D. thesis for his work on air traffic control. His thesis title was “Computational Control of Networks of Dynamical Systems: Application to the National Airspace System.”

Shardul Rajeev Deo received the Nicholas Hoff Graduate Student Award for the M.S. student with the highest grade point average.

Kasidit Leoviriyakit was awarded the Cannon Summer Fellowship in Memory of Wen- Wei Chang for academic achievement and departmental service.

Aldo Rossi won this year’s staff award for his technical support of the experimental research program in the department. Aldo’s help is appreciated by many generations of experimental Ph.D. students who benefited from his superb skill in fabricating machined parts and his guidance in the use of the machine shop tools.

Professor Bob Twiggs received the Dean’s Award for industry education innovation. One faculty member in the School of Engineering wins this distinguished award each year. The citation reads:

In appreciation for exemplary leadership, innovation, resourcefulness, and partnership in bringing the Stanford curriculum to industry engineers through the Spacecraft Design Graduate Course Series. Your passion and commitment to teaching of space systems design sets a standard of excellence in education for industry.

The AIAA awarded Professor Ilan Kroo the Dryden Medal for Research. He delivered the Dryden Lecture in Research in Reno in January. One of the highest tributes given by the AIAA, the Dryden Medal for Research is given in memory of Hugh Dryden, an aerospace pioneer and director of NACA from 1947 until the creation of NASA in 1958.

Faculty and Staff News Professor Sanjiva Lele was named a Fellow of the American Physical Society at the annual meeting of the Division of Fluid Dynamics. He also was one of three faculty members honored with a Stanford Asian American Award, presented by the campus Asian American community. Professor Per Enge was named an IEEE Fellow for his contributions to Global Positioning System applications. Per also has been named to the endowed Kleiner Perkins, Mayfield, Sequoia Capital Professorship in the School of Engineering.

The status of Fellow in a professional society is one of the most prestigious honors of that society, and is bestowed only upon a very limited number of senior members who have made outstanding contributions to science and engineering. Congratulations to Sanjiva and Per for achieving this wonderful honor!

Professor Brad Parkinson continues to garner major awards for his contributions to GPS. Recently, it was announced that he will receive the 2004 ASME Medal, the most distinguished award given by the American Society of Mechanical Engineers. The citation reads:

For outstanding leadership in the development of the global positioning system, which has provided significant freedom and safety to the traveling public.

In the past few years, Brad has received three of the most important awards in engineering: the IEEE Simon Ramo Medal (2002), the NAE’s Charles Stark Draper Prize (2003), and now the ASME Medal.

Professor Brian Cantwell was elected to the National Academy of Engineering (NAE) for his work on the space-time structure of turbulent flows and for the development of fast-burning fuels for hybrid propulsion. We now have five non-emeritus Aero/Astro faculty who are members of the NAE.

Two of our faculty members were up for reappointment or promotion this year:

Juan Alonso was promoted to Associate Professor with tenure. He arrived at Stanford in 1997 after receiving his Ph.D. from Princeton University. Juan synthesizes extremely difficult and complex numerical simulations that bridge the disciplines of computational fluid dynamics and computational structural dynamics. His work has brought him to the forefront of modern research on the use of high-fidelity simulations for multidisciplinary optimization. He recently carried out a combined aerodynamic and structural optimization of a complete aircraft configuration for low sonic boom design of supersonic commercial aircraft. This is a field that is becoming increasingly important, as complex issues will affect the future growth of commercial aviation (for example, the subtle effects of further noise reduction and pollutant emissions below current low levels). Furthermore, there is little doubt that high-fidelity multidisciplinary simulations will become more significant in a wider variety of engineering fields.

Sanjay Lall was reappointed Assistant Professor for a three-year term. He came to Stanford in 2000 with a Ph.D. from Cambridge University. Sanjay’s research addresses the complex problem of controlling and coordinating multiple aerospace vehicles. Since coming to Stanford, he has established a very strong, well-funded research program. Through his research and through numerous invited lectures and workshops, Sanjay has become a recognized leader in the field of distributed control and communications for complex networked systems. This emerging field has many critical aerospace applications. Distributed control and communications is sure to become a key area of research in the Aero/Astro department in the years to come. Staying Connected I encourage you to keep abreast of the activities in the department by visiting our website at aa.stanford.edu and by remaining an active member of our alumni community by keeping us apprised of your activities and whereabouts. You can log on to soe.stanford.edu/alumni/ update.html to update your contact information. We look forward to hearing from you.

With best regards,

Brian J. Cantwell Edward C. Wells Professor Chair, Department of Aeronautics and Astronautics