Waves of Destruction: Launch of SDO Adam Jacobs Mentor: Dr. Dean Pesnell NASA Goddard Space Flight Center Code 671 Summer Internship 2010

Project Description Atlas 5 Rocket (With SDO Payload) Generating Waves What I Did Described and explained several atmospheric related phenomena Have a meteorologist’s perspective Asked Dr. Pesnell many questions everyday. (See YouTube video)

Launch Topics Trajectory of Atlas 5 Rocket Crepuscular Ray Prandtl-Glauert Collar

Launch Topics Sundog Rocket Generated Waves Interaction of Waves and Sundog

Atlas 5 Rocket Trajectory The Atlas 5 carrying SDO, went Mach 1 somewhere between 8.5 and 9km Plotted sound speed using temperature profile.

Crepuscular Ray How Ray Is Created Light is scattered by particles in the atmosphere. Rays are visible when there is an obstruction. What the Ray Told Us The cloud layer height and depth Corresponds with possible cloud layer in sounding

Prandtl-Glauert Collar How the Prandtl-Glauert Collar Forms Not rare or unheard of for rockets (See Ares rocket at right). Effect of Compressibility. Mark of Subsonic to Transonic Mach range 0.8 – 1.2 Forms due to a sudden pressure drop along surface of body at shock front. Homogenous Nucleation Occurs What Collar Told Us Transonic to Supersonic Transition

Sundog How it’s Created Need a layer of falling ice crystals. In our case, the crystals most likely were hexagonal plates. Falling crystals become nearly horizontal and refract light by 22 degrees

Waves How they formed Rocket created a pulse. Generated by the shock front or thermal expansion of plume. Short pulses create wide ranges of wavelengths. Dispersive wave packet generated. Group velocity observed is about 100 m/s. Wave Type Most likely compression waves. Particle Densities Plate Orientations

Inadvertent Sundog-Waves Interaction Problem of Visibility and Invisibility Sundog disappears with the passage of wave packet. Wave packet was visible both within and away from sundog. Mechanism? Two Possibilities

Reorientation of Ice Crystals Disruption of Horizontal Orientation Wave passage causes turbulence White light shimmering. Waves visible outside of sundog area. Possibly due to increases and decreases in ice crystal densities.

Rapid Sublimation and Deposition of Ice Crystals Temperature increase of at least 25K needed at distance 300 m away. Increase of around 10K would only accelerate growth. Temperature perturbations usually drop off as 1/SQRT(distance).

My Experience at NASA GSFC What I Learned I was exposed to a wide variety of knowledge, from visibility of micrometeorites, to fundamentals of astrophysics. Insight to My Future Field of Study This internship helped strengthen my knowledge of physics and motivated me to continue with an added physics major. Thanks Dr. Dean Pesnell Dominic Dr. Clark ULA for flight data Peter Nishu Shea