Tag Archives: aerospace

Spring 2019/Lecture 6/Coordinate Systems and Time – 8 Feb 2019

You should have turned in your assignment by this lecture. My apologies for the issues getting the recordings online. We covered different Earth-bound reference frames and timing systems.

Sign up for updates here: OD Course Landing Page (Syllabus/Schedule)

Slides: L6 Slides – Coordinate Systems and Time

[youtube https://www.youtube.com/watch?v=_3TbLZ-8kkw&w=560&h=315]

Previous lectures:

 

 

Spring 2019/Lecture 5/Perturbed Motion – 6 Feb 2019

Sorry for the missed lectures on Friday and Monday. I was out sick. Assignments are due on Friday. We covered perturbations to orbital motion. We examined contributions from gravitational and nongravitational sources to the two-body motion.

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Slides: L5 Slides – Perturbed Motion

[youtube https://www.youtube.com/watch?v=HZjksLbF4go&w=560&h=315]

Previous lectures:

 

 

Spring 2019/Lecture 4/Two Body Problem – 30 Jan 2019

We resumed today with orbital mechanics. We covered the two-body problem, introduced Kepler’s problem (time doesn’t relate well to true anomaly), and sprinted to the state transition matrix. We will resume with perturbations and additional bodies considered on Friday.

Sign up for updates here: https://mailchi.mp/d95b0d174531/odcourse

Slides: L4 Slides – Two Body Problem

[youtube https://www.youtube.com/watch?v=Mx6PEYk_RQE&w=560&h=315]

Previous lectures:

 

 

Updates: Ph.D. Candidate

I’ve officially passed my qualifying exams. I took my qualifiers in both Intermediate Dynamics and Space Systems. Having passed both I am officially a Ph.D. Candidate. Time to begin preparing for my thesis proposal.

Next semester will see the completion of a satellite ground station at Alabama (more on that later), the publishing of an Orbit Determination course, and my proposal.

I can’t wait to return to my research! It’s been languishing as I focused on qualifiers.

Lecture 3 – Orbital Mechanics Review B

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Lecture

I pick up again by reviewing the solution to the problem assigned during Lecture 1. (The link will take you to a solution using C++ on GitHub). A few common coordinate systems and reference frames are introduced, orbital perturbations are introduced, and an example problem to be solved in Lecture 4 is given to the class to start on.

[youtube https://www.youtube.com/watch?v=FlcF9AoNBUo]

Previous Lectures

Lecture 2

Lecture 1

Resources

Lecture 3 – Review Of Orbital Mechanics B

Lecture 2 – Orbital Mechanics Review A

Lecture 1 – Orbit Determination Concepts (slides)

AppendixA-ProbabilityAndStatistics

Lecture 2 – Orbital Mechanics Review A

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Lecture

We review orbital mechanics and Newton’s law of gravitation to prepare for orbit determination. We will cover the two body problem, orbital elements, and perturbing accelerations. We won’t finish the entire lecture today. We will continue on Monday.

[youtube https://www.youtube.com/watch?v=eBekNtOqy-k]

Previous Lectures

Lecture 1

Resources

Lecture 2 – Orbital Mechanics Review A

Lecture 1 – Orbit Determination Concepts (slides)

AppendixA-ProbabilityAndStatistics

Lecture 1 – Orbit Determination Concepts

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Lecture

The inherent characteristics of an orbit determination (OD) problem are introduced. Dynamic state estimation, observations, linearization, and the state transition matrix are discussed. At the end, I have left a practice problem that we will review on Friday, 8 June. We throw a satellite up and watch it come down while introducing some important concepts.

[youtube https://www.youtube.com/watch?v=0g0QzppL1Ow]

Resources

Lecture 1 – Orbit Determination Concepts (slides)

AppendixA-ProbabilityAndStatistics

Statistical Orbit Determination

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Class time/Preliminary Notes

I will be teaching a statistical orbit determination course this summer. This will be on my own time. All lectures will be posted to YouTube. I will be teaching the course out of Bob Schutz’s, Byron Tapley’s, and George H. Born’s, Statistical Orbit Determination. Feel free to use any textbook you desire but the problems and solutions will be assigned from this text. I have included some precursor notes in question and answer format on statistics and probability below.

AppendixA-ProbabilityAndStatistics

Syllabus

AEM_StatisticalOrbitDetermination_Syllabus_CRS

STATISTICAL ORBIT DETERMINATION

EXECUTIVE SUMMARY:

Orbit Determination (OD) is the problem of determining the best estimate of the state of a spacecraft whose initial state is unknown, from observations influenced by random and systematic errors, using a mathematical model that is not exact. Mordern OD is used to support all space missions from JSpOC’s observations of artificial Earth satellites to the International Space Station’s trajectory planning incorporating elements of probability, statistics, and matrix theory. A special projects class is needed to cover this vital part of the space curriculum that arguably makes the backbone of any space program.

DISCUSSION:

Modern OD approaches have been developed by the NASA Jet Propulsion Laboratory (JPL) to fulfill Earth and planetary navigation requirements and at the NASA Goddard Space Flight Center (GSFC) and the Department of Defense Naval Surface Weapons Center in applications of satellite tracking to problems in geodesy, geodynamics, and oceanography. The Joint Space Operations Center (JSpOC) at Vandenberg Air Force Base, the Conjunction Assessment Risk Analysis (CARA) at GSFC, and Trajectory Operation Officers (TOPO) at Johnson Space Center (JSC) use modern OD techniques in applications of satellite tracking, conjunction assessment, and protecting vital assets from the International Space Station to the National Reconnaissance Office (NRO) spy satellites.

Clearly, OD is an important part of any space mission. The proposed class will use the classical text, Statistical Orbit Determination, by Drs. Byron Tapley, Bob Schutz, and George Born. This basic OD course will cover:

  • Introduction to OD problem
    • Dynamic system and associated state
    • Observations are non-linear functions of state variables
    • Classical well-determined approach
    • Modern over-determined approach
  • Observations to measure satellite motion
    • Ground-based systems: laser, radiometric, etc.
    • Space-based systems: GPS, etc.
    • Error sources and media corrections
  • Non-linear OD reduced to linear state estimation
    • Application of linear system theory
    • Incorporation of algorithms to computational environment
    • Sequential processing of observations
    • Control of real-time processes

This will be supported by background and supplemental information in:

  • Probability and Statistics
  • Review of Matrix Concepts
  • Examples of State Noise and Dynamic Model Compensation
  • Solution of the Linearized Equations of Motion

Students can expect to incorporate their classroom knowledge into real-life by building optical and radiometric sensors supporting The University of Alabama’s new satellite ground station.

LECTURES:

Lecture 1 – Orbit Determination Concepts

Lecture 2 – Orbital Mechanics Review

Space Operations and Support Technical Committee

Today I received official notice: I am a member of the AIAA Space Operations and Support Technical Committee (SOSTC). The SOSTC Charter:

The Space Operations and Support Technical Committee (SOSTC) is concerned with all aspects of civil, military, and commercial space operations and support, including direct and supporting operations, the systems and software affecting operations, and space operations and operational risk management. The SOSTC addresses all types of space operations, including manned and unmanned space operations from low Earth-orbiting to deep-space systems. It is involved with all phases of mission operations, including pre-launch and launch activities, early mission commissioning activities, on-orbit activities, cruise and encounter activities, post-landing activities, and end-of-life operations. The SOSTC likewise addresses space related operational support activities, including training, servicing, mission planning, flight dynamics, telemetry transmission, command and control, and data handling, processing, analysis, and storage.

I’m very thankful for this opportunity.

Post-Flight Analysis Report (PFAR) of RX1

 

SUMMARY:

Christopher R. Simpson built a rocket to pass his Level 1 (L1) certification from the National Association of Rocketry (NAR). The rocket was a kit from Madcow Rocketry; the “Frenzy,” [1]. The RX1 used an Aerotech H550ST-14A, “Super Thunder,” motor with a total impulse of 71.9 lb-sec and a burn time of 0.57 sec. Construction of the rocket, flight, and recovery are reviewed to analyze and critique operations.

Post-Flight Analysis Report (PFAR) attached here: PFAR-RX1 (26 Feb 2018)

YouTube link to flight: https://www.youtube.com/watch?v=Xqff5scf-00

ACKNOWLEDGEMENTS:

A big thank you to Karson Holmes for certifying/critiquing me and William Ledbetter for making the trip to watch the fun take off! Also, a special thanks to Alabama Rocketry for allowing me to use their adapter.

RESOURCES:

Rocket Used: https://www.madcowrocketry.com/4-frenzy/

Motor/Supplier Used: https://csrocketry.com/rocket-motors/aerotech-rocketry/motors/38mm/dms-rocket-motors/aerotech-h550-14a-super-thunder-dms-rocket-motor.html

Alabama Rocketry Facebook Page: https://www.facebook.com/alabamarocketry/

Pheonix Missile Works Facebook Page: https://www.facebook.com/groups/58541022592/