Engineering topics
Thompson, Paul
Publications and source records attributed to Thompson, Paul.
Joint IAEA/NNSA International Workshop Nuclear Forensics Methodologies for Practitioners 2013 Scenario Based Exercise – Version 4.0 Instructor’s Manual
[Participants will serve as border guards for Reimerland. They will be given brief instruction on the operation of hand-held RadioIsotope DetectorS (RIDS) and be provided an intelligence briefing that tells them to be on the lookout for suspicious activity at their post. Their instruction will include directing suspicious vehicles to a location for secondary screening. If, after secondary screening, suspicions of a criminal act involving nuclear and or radioactive materials remain, participants have been instructed to request assistance from the NLEA, who will then setup and manage a radiological crime scene. Participants will watch a demonstration of two vehicles containing radioactive materials driving through and setting off a portal monitor. The first vehicle, a semi-tractor trailer, sets off only a gamma alarm. After the driver provides a shipping manifest of fertilizer, participants, posing as border guards, are expected to waive this vehicle through inspection. The second vehicle, an SUV, set off both gamma and 2 neutron alarms. The alarming of the neutron monitor should prompt participants to set up a secondary inspection of the vehicle immediately. The driver of the vehicle indicates he is in legal possession of an industrial instrument containing an old 133Ba source that has decayed to a level no longer requiring official paperwork according to the IAEA and internationally accepted transportation regulations. Authorities have verified that the industrial source does fit the description of one that is sold commercially. However, upon setting up a secondary screening, participants will use hand-held detectors to locate several other radioactive sources emanating from a black duffle bag in the rear of the vehicle (Figure 1). Hand held detectors detect the presence of 133Ba, and Pu. Upon questioning, the driver only commits to having the 133Ba industrial source and cannot account for the detection of neutrons within his vehicle. Since neutron alarms also sounded, participants should indicate that a neutron alarm would be inconsistent with a 133Ba source alone and should therefore conclude further investigation is warranted. This will prompt participants to call in a response team from the NLEA to set up a radiological crime scene around the vehicle in question. The response team is able to shoot a 3-D X-ray radiograph of the duffle bag without moving it to ensure it is rendered safe and moveable without disturbing the contents in the field (Figure 2). At this point, the duffle bag is entered into inventory as evidence and a chain of custody form is initiated. Swipes are taken from the outer bag to confirm there is no dispersible contamination. The bag and its contents are considered valuable for the investigation by the lead investigator. He determines the duffle bag is safe to transport to RRL for evidence inventory and analysis. The duffle bag and its contents are packaged and sent off to the RRL.]
Mars Science Laboratory Orbit Determination
Mars Science Laboratory (MSL) Orbit Determination (OD) met all requirements with considerable margin, MSL OD team developed spin signature removal tool and successfully used the tool during cruise, A novel approach was used for the MSL solar radiation pressure model and resulted in a very accurate model during the approach phase, The change in velocity for Attitude Control System (ACS) turns was successfully calibrated and with appropriate scale factor resulted in improved change in velocity prediction for future turns, All Trajectory Correction Maneuvers were successfully reconstructed and execution errors were well below the assumed pre-fight execution errors, The official OD solutions were statistically consistent throughout cruise and for OD solutions with different arc lengths as well, Only EPU-1 was sent to MSL. All other Entry Parameter Updates were waived, EPU-1 solution was only 200 m separated from final trajectory reconstruction in the B-plane
Cassini Orbit Determination Performance (July 2008 - December 2011)
This paper reports on the orbit determination performance for the Cassini spacecraft from July 2008 to December 2011. During this period, Cassini made 85 revolutions around Saturn and had 52 close satellite encounters. 35 of those were with the massive Titan, 13 with the small, yet interesting, Enceladus as well as 2 with Rhea and 2 with Dione. The period also includes 4 double encounters, where engineers had to plan the trajectory for two close satellite encounters within days of each other at once. Navigation performance is characterized by ephemeris errors relative to in-flight predictions. Most Titan encounters 3-dimensional results are within a 1.5 formal sigma, with a few exceptions, mostly attributable to larger maneuver execution errors. Results for almost all other satellite encounter reconstructions are less than 3 sigma from their predictions. The errors are attributable to satellite ephemerides errors and in some cases to maneuver execution errors.
Stardust-next : Lessons Learned from a Comet Flyby Mission
The Stardust-NExT (New Exploration of Tempel) mission, a follow-on to the Stardust prime mission, successfully completed a flyby of comet Tempel-1 on 2/14/11. However there were many challenges along the way, most significantly low propellant margin and detection of the comet in imagery later than antici-pated. These challenges and their ramifications forced the project to respond with flexibility and ingenuity. As a result, the flyby at an altitude of 178 km was nearly flawless, accomplishing all its science objectives. Lessons learned on Stardust-NExT may have relevance to other spacecraft missions.
Navigating Stardust-NEXT: The Road to Tempel 1
The Stardust-NExT (New Exploration of Tempel) mission, a follow-on to the Stardust prime mission, successfully completed a flyby of comet Tempel-1 on 2/14/11. However there were many challenges along the way in navigating this mission to its successful conclusion, most significantly low propellant margin and detection of the comet in imagery later than anticipated. These challenges and their ramifications forced the navigation team and the project to respond with flexibility and ingenuity. As a result, the resulting flyby at an altitude of 178 km was nearly flawless, accomplishing all its science objectives.
Mission Enabling and Enhancing Spacecraft Capabilities with MicroNewton Electric Propulsion
The capability to significantly improve current spacecraft pointing, precision orbit maintenance and disturbance mitigation were considered using precision, quiescent microNewton electric propulsion systems. Analysis results showed that electric propulsion systems operating in the microNewton to hundreds of microNewtons thrust range can offer significant improvements over state-of-the-art mission capabilities to enable 30 m Earth-fixed orbital tubes, constellation spacecraft position control to within nanometers and exoplanet observatory pointing with 0.1 milliarcsecond precision. Specific thrust levels and profiles required to support these capabilities are discussed.
NASA Master Teacher Re-Certification Program
Edward Waters College is submitting a final report covering the grant period from January 1999 - April 30, 2000. The Teacher re-certification program at Edward Waters College created a high quality professional development opportunity for middle and high school science teachers which will contribute to the improvement of science education and the use of innovation technologies in the classroom for years to come. The following goals and objectives were met and exceeded during the grant period. 1) A focused and relevant educational technology curriculum based on National Science Education Standard and state-of-the art educational resources that are accepted as one of the qualifications for re-certification in the scientific discipline in Duval County, Florida. 2) The program goal was to recertify 40 middle and high school science teachers over a two- year period. This goal was met and exceeded the projected number by recertifying over 80 middle and high school science and math teachers over a two-year period. 3) Teachers that were recertified were given an opportunity to public information that they developed on EWC's Web page or develop a web page of their own. Area schools were made aware of this information through various forms of communication with the teachers in Duval County School District, i.e., flyers sent from EWC to participants, school newspapers, word of mouth, etc. 4) A multimedia technology resource lab is available at EWC for use as a "Learning Lab" for class field trips by Duval County teachers.
Selection of orbits for the CRRES dual mission satellite
The Combined Release and Radiation Effects Satellite (CRRES) is somewhat unusual, in that it performs related scientific experiments in two very different orbits. The selection of the Low Earth Orbit and Geosynchronous Transfer Orbit requires a number of scientific and engineering trade-offs. Issues in this design process discussed here are launch and insertion capabilities, altitude regimes of scientific interest and orbit stability, ground track and lighting considerations, lifetime of both missions, and the transfer between the two orbits.