aeng-3150-spring-2020

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• Latest News/Information

  • • The Zoom Meeting for our brave new world

    • Zoom meeting link

    • Meeting ID: 274 320 477

    • Password: astro

    • Final Exam Updates

      • The answer sheets have been pushed to your shared folder (with the long name aeng3150sp2020final_answerSheet_[your name].pdf. When you are finished with your exam, please copy the answers (except as noted on the sheet) onto this form and included it in your final exam.

      • For problem 13 (Captain Marvel's Lambert Problem), the last part asks you to reduce the travel time by a certain number of days. For some of you, this results in a travel time less than the minimum-possible time. This was not supposed to be a trick question. You have two options

        1. If you've already solved the problem, and your new travel time worked just fine, you don't have to change a thing

        2. If you haven't started the problem, or if you ran into this roadblock, please change your new travel time for part (f) to t_min + 5 days. (Check out "Things you need to know about Orbital Mechanics", below, for the equation that computes t_min.)

• Course Resources

  • • Syllabus (Spring 2020)

    • Course internal website (Spring 2020) *

• Useful (and semi-useful) things

  • • Things* you need to know about orbital mechanics on one (double-sided) page [revised March 2020].

    • A 15-minute primer on using Matlab.

    • The Solar System

      • Quick overview of the solar system. *

      • A scale model of the solar system, built in the desert (7 Minutes)

    • AGI's Spacebook (real-time viewer of all cataloged spacecraft in orbit)

• Presentations

  • • Course introduction (Spring 2020) *

• • Prussing Chapter 1:

    • • Classic orbits: ellipse and hyperbola *

  • Prussing Chapter 2:

• • • Calculating time as a function of position (13 Minutes) *

    • Examples

      • • Time from position (PDF) *

        • Position from time using Newton's method (PDF) *

• • • • Video walkthrough (16 Minutes) *

• • • Prussing, Chapter 5

• • • • Lambert Example 1: Earth orbit *

      • Lambert Example 2: Solar orbit *

• • • Prussing Chapter 6:

• • • • Introduction to rocket propulsion (45:28) *

      • The Rocket Equation (11:44) *

      • Rocket equation summary *

      • Handouts *

• • • Prussing Chapter 7:

• • • • Handouts *

• • • Mission Flowdown *

    • Interplanetary Mission Analysis *

• • • • Overview of the Swingby (14:53 and handout - the video cuts off abruptly, but the lesson was over) *

      • Jupiter Swingby Example (13:35 and handout) *

      • Venus Swingby Example (29:13; handout and calculations) *

• • • Earth Orbits *

• Recorded Classes

  • • Tue 03/24

      • These items were covered in this video (25:21) *

• • • • • Introduction/mini-reunion, general logistics

        • Walk-through of the internal website (see below) and calendar for the rest of the time

        • Installing STK or going online for STK

        • HW06 and Chapter 3

        • How I'm going to get Midterm 1 back to you and review it

• • • • Chapter 6 part 1 (45:28) * and, see handouts, below

• • • • • Intro to rocketry (Goddard & the New York Times)

        • Momentum transfer

        • Fundamental types of rocket propulsion

        • Rocket propulsion examples

• • • Thu 03/26

      • Logistics (10:58) *

• • • • • General questions

        • Reminders about schedules and due dates

        • Where to find files for HW06

        • Please install STK (or tell me that you don't need a license)

        • You must indicate an intent to submit regrades (HW01-04) by Friday

• • • • Chapter 6 part 2 (63:19) *

• • • • • The rocket equation

        • Fundamental parameters, sizing equations

        • Staging

        • Real-world effects (Gravity and Drag), briefly.

• • • Tue 03/31

      • Logistics (8:32) *

• • • • • General questions, logistics

        • Intro to HW07

• • • • Chapter 6 part 3 (59:12) *

• • • • • Real-world rockets

        • Launch sites

        • Digression into the Farewell Dossier

        • Mission failures (Challenger)

• • • • Interplanetary Missions (6:35) *

• • • • • The patched-conic approximation

        • Coordinate transformations

• • Thu 04/02

    • • Logistics (5:20) *

      • Interplanetary Missions, Part 2 (71:43) *

        • Patched conic

        • Coordinate transformations

        • Heliocentric orbit transfers (Hohmann)

          • Limits of accuracy and spheres of influence

          • Synchronization (due to planetary motion and long transfer times)

        • Phase 1: Hyperbolic Escape

        • Phase 3: Hyperbolic Entry

        • Flyby

        • Hohmann transfers to the outer planets (do not try this yourselves)

  • Tue 04/07

    • • General logistics, questions about the exam formats (28:05) *

      • These things came after class, but are relevant for HW08

        • Overview of the Swingby (14:53 and handout - the video cuts off abruptly, but the lesson was over) *

        • Swingby Example (13:35 and handout) *

  • Tue 04/14

    • • Full class (73:21) *

      • Personal Case Study

      • STK Project (part 3 of the STK assignment)

      • Much discussion of swingbys

      • Out-of-plane swingbys (not on the exam)

  • Thu 04/16

    • • First half (38:52) *

        • Reminder of the calendar

        • Format and content of the second Midterm (see highlighted stuff, below)

        • Review of Midterm 1

      • Second half: open discussion on hypersonic vehicles, Hyperloops, infrared micobolometers and global politics. (Recording not saved. For some things, you just have to join us in class!)

• • • Thu 04/30

      • First hour (62:32) *

        • Calendar updates

        • Timeline for getting Midterm 2 back

        • Broad overview of the final exam

        • Discussion of Midterm 2 issues

      • Remainder of class (not recorded)

        • Rockets, favorites/least favorites, colonization, strip-mining the Moon ...

• Midterm Preparation

  • • First Exam:

      • The equation sheet (listed above) will be provided

      • An ancient practice exam 1

      • Solutions to the practice exam

      • A more recent exam 1 (Spring 2019) *

• • • • • Solutions * to this exam. [Apologies in advance for the scrawled solutions; I had not expected to publish this. Also, the answer to 6h was incorrect and has been noted.]

• • • • Spring 2020 exam * and solutions *.

• • Second Exam

    • Format for 2020: Take-home midterm covering the topics of HW04 - HW08. [Though, obviously, this material builds on what you did for HW01 - HW03.]

      • At 9:30am on 04/23, the exam will be loaded into your Google Drive classroom folder.

      • You have 24 hours to complete the exam and return it to the same folder. [I will not grade any submissions until the 24-hour period is complete, so you are free to upload new solutions during that window of time.]

      • Your solution must be hand-written (either in the exam printout, or you can use your own paper) and loaded into a single document named aeng3150sp2020mid02_lastname_firstinitial.pdf

      • The exam is open-book, open-notes (including all files on this website) but you are not allowed to work with anyone else. All work must be demonstrably your own.

      • There will be multiple versions of the exam: the same problems, but different numbers; the same general multiple choice / true-false, but with the wording changed.

      • Bonus equation sheet for Exam 2: Rocket Equations

      • Practice Exams

        • Spring 2014: Exam 2 * and Solutions *

      • Spring 2018: Exam 2 * and Solutions *

• Homework Assignments

• • Regrade policy: we accept regrades if you believe that your grade was incorrect, or if you are requesting partial credit [i.e., if you used the wrong value of radius, or if you calculated part (b) incorrectly and everything that follows depended on your answer to part (b)]. In both cases, please return your assignment with the regrade request(s) clearly labeled/marked/circled/noted, and please explain why a regrade is in order. If we cannot easily discern your regrade request, we'll return it to you unchanged. All regrades are due Monday (05/04).

    • HW01: Stop your grinnin' and drop your linen. Due 01/28.

    • HW02: You can learn all the math in the 'Verse, but you take a boat in the air that you don't love, she'll shake you off just as sure as the turning of the worlds. Due 02/04

    • HW03: You know, sometimes, I amaze even myself! Due 02/11.

    • HW04: Never Give Up! Never Surrender! Due 02/18.

    • HW05: You're Backed into a Hyperdimensonal Corner. Due 03/24. [Check your email for instructions on submission.]

    • HW06: Nothing goes over my head. My reflexes are too fast; I would catch it. Due 03/31.

      • The equations needed for HW06 are directly out of Prussing, Chapter 3. In fact, you only need pp. 46-53 (stop before you get to Example 3.1 on p. 54).

      • I don't think it's worth spending class time on this. (If I'm wrong, let me know, and we'll spend Thursday time on this)

    • HW07: I don't believe in the no-win scenario. Due 04/07.

    • HW08: Space is disease and danger wrapped in darkness and silence. Due 04/15.

    • Project 1: Systems Tool kit (worth 10% of final grade, as per the syllabus)

      • Systems Took Kit Reference Page

      • Part A (30 pts): Register for and complete the STK Level 1 Certification. Due 04/21

      • Important reminder: you are only allowed two weeks to complete Level 1 certification; this is a hard cap from Analytical Graphics, not SLU. Do not start the process until you're ready to finish it in two weeks!

        • Post a screencap/PDF of your certification in your course folder, named lastname_firstinitial_STK01.pdf (or .jpg or whatever)

        • If AGI has not sent your certification, yet, then upload your zipped submission and the email acknowledgment from AGI that you have submitted.

        • Email the instructor when it's there

        • Level 1 Tutorials (AGI website)

      • Part B (50 pts): Register for and complete the STK Level 2 Certification. Due 05/07

      • Important reminder: you are only allowed two weeks to complete Level 2 certification; this is a hard cap from Analytical Graphics, not SLU. Do not start the process until you're ready to finish it in two weeks!

        • Post a screencap/PDF of your certification in your course folder, named lastname_firstinitial_STK02.pdf (or .jpg or whatever)

        • If AGI has not sent your certification, yet, then upload your zipped submission and the email acknowledgment from AGI that you have submitted.

        • Email the instructor when it's there

        • Level 2 Tutorials (AGI website)

    • Part C (20 pts): Part C is cancelled, but a very slimmed-down version will be part of the final exam. Design an Earth-orbiting internet constellation. Updates/changes in red, including deletions. Due 04/30

      • Seizing an opportunity in these troubled times, your mission is to develop the "best" (see below) Earth-orbiting internet constellation. Parameters under your control

        • Number of spacecraft and their orbits (see below)

        • On-board power of the transmitter

      • Your marketers have identified five key cities to serve (Lat Long in degrees, use Terrain altitude)

        • New York, NY (40.7142700 -74.0059700)

        • St. Louis, MO (38.6272700 -90.1978900)

        • Adelaide, Australia (-34.9286600 138.598630)

        • Nairobi, Kenya (-1.2833300 36.8166700)

        • Lima, Peru (-12.0431800 -77.0282400)

      • Your mission is to provide continuous internet coverage for all five cities at a data rate of greater than 1 Mbps

      • For the purposes of this study, assume that your spacecraft are in position by 00:00:00 UTC 1 September 2020 and the simulation runs through 00:00:000 8 September 2020.

      • Your score will be determined as follows

        • Costs:

          • Each spacecraft has a base cost of $500,000

          • The transmitter costs $50,000 + $2,000 * Power^2 (where Power is the transmit power in Watts)

          • Any number of spacecraft can be launched into the same orbit plane for a cost of $50,000/spacecraft + $[0.057*(semimajor axis [km])² - 1,500,000] $1,000,000 + $50,000/spacecraft.

            • "Same orbit plane" means that the first five Keplerian elements are identical: semimajor axis, eccentricity, inclination, argument of perigee, RAAN. Only the Mean Anomaly can be different.

            • For orbits, assume TwoBody propagation

          • Assume they have on-board power to spread out along the orbit plane, but plane-change maneuvers are not permitted

          • Assume it costs $1,000/day per spacecraft for operations

        • Revenues:

          • For every second that a city has at least 1 spacecraft in view (both sensor cones overlap) in range with the link closed, your company earns 1 cent ($0.01)

          • Assume the 7-day simulation is good enough to project a 365-day revenue plan

        • Mission score = (Annual Revenue) - Costs

      • Assumptions

        • Any spacecraft with an elevation above 10° is visible

        • The transmitter on the spacecraft is always perfectly nadir-pointing with a conical half-angle of 25°

        • The receiver on the ground is always perfectly zenith-pointing with a conical half-angle of 25°

        • The downlink must be closed with a signal-to-noise ratio above 13 dB

        • We only need to look at the downlink

      • Grading:

        • 4 pts - download your STK Scenario and all items into your course folder and fill out the scoresheet (coming soon)

        • 6 pts - supply a writeup of the design drivers as you see them, what sorts of iterations/changes you made along the way, and how you arrived at your final design. As part of this writeup, please take a look at least two existing communications constellations and compare/contrast the number of spacecraft and their orbits to your design. Think about why those constellations differ from yours [hint: what parts of the Earth do they cover, and what kinds of data are they moving through their system? How does this contrast with your mission?]. Example constellations: Iridium, Globalstar, OneWeb, Starlink, NASA TDRS, Inmarsat.

        • 10 pts - your final design score (4 pts for meeting the minimum score, then scaled up from there)

    • Project 2: Case Study of Spacecraft Contractor (replacing the Team Project in the syllabus, still worth 5% of the final grade). Due 05/07

      • Topic [1 pts]: Find a space mission or contractor that interests you. Please review the other parts of the assignment before settling on a topic. If you cannot find sufficient information, you will need to change topics.

        • A contractor is an organization that builds all or part of a space mission: the spacecraft, the reaction wheels on the spacecraft, the launch vehicle, the on-board thrusters, the mission control center.

        • Examples: the Galileo Mission, OneWeb [the constellation], OneWeb [the company in bankruptcy], SpaceX, Blue Canyon, Virgin Orbit, Ball Aerospace, Aerojet, MOOG. [I can provide guidance if you're unsure.]

        • "NASA" or "Boeing" are too big for this project; if you want to study something big like that, pick one of their missions. (For example, you could look at NASA's ISS Mission Operations center.)

      • Schedule [10 pts]: Provide a brief overview of the mission or contractor

        • Contractor: When did the company start? What did they make when they started, and has the product line changed since then? How large is the company, today?

        • Mission: What was the purpose of this mission? Has it changed from its inception? What were the main contractors on the mission? What are the key points in the mission timeline (from the start of the contract until today)?

      • Cost [5 pts]: Provide rough estimates of the financials (annual sales of the company, total cost of the mission)

      • Performance [10 pts]: Identify similar/competing missions/contractors.

        • Contractor: What other companies do the the things that this company does, and how do they distinguish themselves from the competition (i.e., stay in business)?

        • Mission: Is this mission part of a series of missions (e.g., the search for life on Mars)? In what unique ways does this mission contribute? (In other words, why spend money on this new mission when the other missions were already paid for?)

      • Risk [5 pts]: Has the mission or contractor had challenges it had to overcome?

      • Careers [10 pts]: Identify one person (if able) or type of job that is performed at this company. How would one go from where you are now to holding that job? (Education, skills training, personal abilities.)

      • Quality [4 pts]: The report should be on the order of 3 pages (750 words), submitted in PDF format to your class folder.

      • Je Ne Sais Quoi [5 pts]: For going above and beyond the assignment, including reflecting on what you've learned.

• What Have We Learned?

• • How often is the outer-planet "Grand Tour" available?

    • • Every 177 years for all four, if Wernher Von Braun is to be believed

      • Three out of the four seem to line up every 60 years or so, if this random website is to be believed

• • • How Do We Deflect an Asteroid?

      • Right now, we don't (it's the Deep Impact outcome vs the Armageddon outcome)

      • Airbus has a plan to use telecom-sized (2000 kg) spacecraft as a kinetic intercept vehicle, assuming a 3-year advance notice

      • MIT published a study about what it would take to prevent such a collision, and again it requires 5+ years advance notice to get the results right

Planetary Constants

Universal gravitational constant (G): 6.67408 × 10^-11 m³/( kg s²)