For more than twenty years, Modern Control Systems has set the standard of excellence for undergraduate control systems textbooks. It has remained a bestseller because Richard Dorf and Robert Bishop have been able to take complex control theory and make it exciting and accessible to students. The book presents a control engineering methodology that, while based on mathematical fundamentals, stresses physical system modeling and practical control system designs with realistic system specifications. ABOUT THE COVER The Mars Pathfinder mission is primarily an engineering demonstration of technologies and concepts for use in future Mars missions. The Mars Pathfinder spacecraft was launched aboard a Delta II-7925 launch vehicle on December 4, 1996 from the Cape Canaveral Air Station in Florida, USA. The launch is shown in the upper half of the front cover. After traveling 497,418,887 km, the spacecraft impacted the Martian surface on July 4, 1997 with a velocity of about 18 m/s. Upon impact the spacecraft bounced up about 15 meters, then continued to bounce another 15 times and rolled to a stop about 1 km from the initial impact point.
The landing site is known as the Sagan Memorial Station and is located in the Ares Vallis region at 19.33 N, 33.55 W. The Sojourner Rover (weighing in at about 10.5 kg) began surface operations on July 6 after rolling off the ramp on all six-wheels onto the Martian soil. The Sojourner Rover is shown in the bottom half of the front cover. The Rover is controlled by operators on Earth using images obtained from the Rover itself. The time delay for signals and images to reach Earth from Mars is about 10 minutes. This time delay requires a degree of control autonomy by the Sojourner Rover. The Rover investigated rocks with interesting names like Barnacle Bill, Yogi and Scooby Doo.