Dawn getting established in orbit around Ceres

The Dawn spacecraft is getting established in orbit around Ceres, preparing for the start of scientific observations. Dawn’s continuous low-thrust ion propulsion causes the spacecraft to fly an unusual trajectory. Chief engineer and mission director Marc Rayman has an excellent posting on the subject in Dawn Journal.

Ceres, imaged from Dawn

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USAFTPS flight tests L1 adaptive flight control laws

“An adaptive flight controller that could help pilots save a critically damaged or out-of-control aircraft is being proposed for possible commercial development following a rigorous evaluation by U.S. Air Force Test Pilot School (TPS) students, using Calspan’s variable-stability Learjet 25 test aircraft.

The L1 controller is designed to automatically intervene in the case of control problems, immediately reconfiguring the flight control system to compensate for degraded flying qualities from mechanical failure or battle damage to a control surface, or even the unintended result of shifting center-of-gravity inflight for better cruise performance. Acting as a backup to the standard flight control system, the L1 is designed to provide safe, predictable, reliable and repeatable responses that would free up pilots to deal with the emergency and further compensate for reduced performance.

In development for more than a decade by researchers at the University of Illinois at Urbana-Champaign, the L1 controller architecture differs from most previous approaches to adaptive control systems. Until now, the standard has been gain-scheduled control systems in which the flight control computer selects the appropriate preprogrammed gains to suit current flight conditions and vehicle configuration. However, the L1 works in real-time to predict transient behavior and estimates lumped uncertainties, rather than every individual parameter that can affect system dynamics; it compensates for them within the bandwidth of a control channel.

The L1 controller comprises three blocks: a state predictor, a fast estimation scheme and a control law. The fast estimation scheme includes a state predictor and a fast estimation law which together approximate the dynamics of the aircraft to generate estimates of the uncertainties. These estimates are provided as input to a bandwidth-limited filter which generates a control signal to the flight control system.

L1 development from theory to flight test has been led by Naira Hovakimyan, a professor of mechanical science and engineering at Illinois, who worked on the concept under Air Force funding between 2004 and 2008 at Virginia Tech with postdoctoral fellow Chengyu Cao (now at the University of Connecticut).”

Link to full article.

Photo of the week

Two F-16 Fighting Falcons from the 31st Fighter Wing, Aviano Air Base, Italy, fly over Europe on March 20, 2015. The aircraft were participating in a flying training deployment with the Estonian air force and also participating in additional, unrelated training with the Finnish and Swedish air forces. (U.S. Air Force photo/Senior Airman Christine Griffiths)

Two F-16 Fighting Falcons from the 31st Fighter Wing, Aviano Air Base, Italy, fly over Europe on March 20, 2015. The aircraft were participating in a flying training deployment with the Estonian air force and also participating in additional, unrelated training with the Finnish and Swedish air forces. (U.S. Air Force photo/Senior Airman Christine Griffiths)

60th anniversary of the first flight of the C-130

On April 7, 1955, the Lockheed YC-130A Hercules conducted its first flight. Four great US Air Force aircraft from the 1950s remain in operation: B-52, C-130, KC-135 and U-2. The C-130 is unique in that it not only remains in service, but in production.

Blue Angels Transitioning to Unmanned Aircraft

It was inevitable.