The NF-15B ACTIVE is the most maneuverable of any F-15 variant, but she didn’t start out that way. This airframe, originally designated the TF-15B (USAF serial number 71-0290), looked much like a typical F-15. She took her first flight on July 7, 1973, as the first two-seat F-15 in history and the sixth F-15 to roll off the assembly line.

    On September 7, 1988, she would have her “second first flight” following major modifications as the STOL/MTD (Short Takeoff and Landing/Maneuver Technology Demonstrator). Modified F-18 stabilators were put in place forward of the wing as canards. Thrust vectoring in the pitch axis was also implemented, allowing takeoff rotation at only 39 knots and drastically shorter landing distances.

    In 1991, the STOL/MTD test program ended, and the USAF loaned the airframe to NASA, who modified it into the NF-15B ACTIVE (Advanced Control Technology for Integrated Vehicles). The pitch thrust vectoring was traded for nozzles that could be vectored in pitch and yaw. This allowed for incredible maneuverability. The bird could perform yawing maneuvers while flying at 30 degrees angle of attack.

    Although never implemented, there were plans to further modify this airframe by removing the vertical tail planes, allowing thrust vectoring to be wholly responsible for yawing maneuvers. This would have been called the F-15 MANX, named after the naturally tailless cat.

    After decades of serving NASA Dryden Flight Research Center (now NASA Armstrong) as a successful experimental testbed for many different test programs, the NF-15 ACTIVE took its final flight in January 2009. On this last flight, she was the oldest still flying F-15. In July of 2015, she was put on static display at NASA Armstrong Flight Research Center on Edwards Air Force Base, California.

NASA Astronomy Picture of the Day 2015 September 4 

Milky Way with Airglow Australis 

After sunset on September 1, an exceptionally intense, reddish airglow flooded this Chilean winter night skyscape. Above a sea of clouds and flanking the celestial Milky Way, the airglow seems to ripple and flow across the northern horizon in atmospheric waves. Originating at an altitude similar to aurorae, the luminous airglow is instead due to chemiluminescence, the production of light through chemical excitation. Commonly captured with a greenish tinge by sensitive digital cameras, this reddish airglow emission is from OH molecules and oxygen atoms at extremely low densities and has often been present in southern hemisphere nights during the last few years. On this night it was visible to the eye, but seen without color. Antares and the central Milky Way lie near the top, with bright star Arcturus at left. Straddling the Milky Way close to the horizon are Vega, Deneb, and Altair, known in northern nights as the stars of the Summer Triangle.