Waves of Destruction: Launch of SDO
-
Upload
natalie-mcmillan -
Category
Documents
-
view
21 -
download
0
description
Transcript of Waves of Destruction: Launch of SDO
Waves of Destruction: Launch of SDO
Adam JacobsMentor: Dr. Dean Pesnell
NASA Goddard Space Flight CenterCode 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 GSFCWhat 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