ENAE 694: Spacecraft Communications, Fall 2026
Instructor and Meetings
- Instructor: Dave Israel
- Email: [email protected]
- Phone: (443) 895-1864
- Meets: Monday evenings, 5:00–8:00 p.m., Martin Hall 1110
- First class: August 31, 2026
- Final assessment: final project due on the university-assigned final-exam date
- Section AED1 is asynchronous
- Joining the live class virtually is optional; no graded work requires real-time attendance
- Recordings and activity prompts are posted on ELMS; short class activities stay open to AED1 for at least 48 hours after the recording is available
Course Purpose
- Spacecraft communications moves commands, telemetry, science, navigation measurements, and other information across imperfect connections
- Goal is not to turn everyone into a spacecraft communications systems engineer
- Leave with an understanding and appreciation of their work: the concepts, factors, and trades behind their decisions, and their effects on the mission
- “Not simply radio. Not simply networking.” This course is about moving mission information through a complete system
Governing Idea
- Everything is a trade. Equations support engineering judgment; they do not replace it.
Course Arc
- Mission needs
- Individual links
- Coverage
- Data delivery
- Network architecture
Learning Outcomes
- Translate mission operations, data volume, latency, completeness, coverage, and resilience needs into measurable communications design targets and constraints
- Construct and interpret link budgets using power, path loss, antenna gain, noise, modulation, coding, and implementation margin
- Explain major antenna, pointing, spectrum, coding, multiple-access, relay, RF-versus-optical, and ground-system trades
- Evaluate coverage and availability using supplied contact data, including total availability, longest outage, and operational consequences
- Analyze buffering, contact schedules, store-and-forward delivery, latency, and routing in intermittently connected networks
- Recommend and defend an end-to-end spacecraft communications architecture that closes its representative links and meets mission-level service needs
- Class 1 summary (“What You Will Be Able to Do”):
- Translate mission needs and provider capabilities into communications design targets
- Build and interpret complete link budgets
- Analyze coverage, availability, capacity, and latency
- Trace data from its source to its final user
- Compare architectures and defend the trades
How We Will Work Together
- Class meetings combine short explanations with worked engineering examples
- Calculate representative cases, change assumptions, predict what should happen, and talk about what each result means
- “We will do the engineering in the room”:
- Introduce the principle
- Work an example together
- Change one assumption
- Predict what changes — and why
- Use homework to extend the example
- Homework builds on work already done together, rather than introducing an unfamiliar calculation cold
- Coverage work: the instructor supplies orbit/contact data and guided analysis tools
- The important part is understanding what the results mean for the mission, not building an orbit propagator
- Some homework may give useful pieces to carry into the final project
Grading
| Category | What it includes | Purpose | Weight |
|---|---|---|---|
| Homework and applied work | Calculations, interpretation, and engineering judgment based on material introduced in class | Practice, feedback, and revision until the work is correct | 70% |
| Final project | Communications design and presentation materials for a mission concept review | Synthesis, engineering judgment, and communication | 30% |
- No separate attendance or engagement grade; no timed midterm or final exam
- Homework can be revised and resubmitted until it is correct
- “The goal is for everyone to learn the material, not for an early mistake to become permanent”
- Instructor will be flexible where reasonable (many students balance jobs and other responsibilities)
Final Project: The Mission Concept Review
- You play the communications systems engineer for a proposed mission
- Develop a preliminary communications design and the presentation materials you would bring to a mission concept review
- Point: show how concepts, constraints, and trades lead to a defensible design — not a heroic amount of documentation
- Submission: a slide deck plus separate written material
- Due on the university-assigned final-exam date (in lieu of a final exam)
- No live presentation or recorded narration (either section)
Schedule
| Date | Class | Topic | Applied focus |
|---|---|---|---|
| Aug. 31 | 1 | The Spacecraft Communications Problem | Mission needs, constraints, data volume, latency, completeness, and the end-to-end problem |
| Sept. 7 | – | No class (Labor Day) | University holiday |
| Sept. 14 | 2 | Received Power and Link Geometry | Decibels, EIRP, free-space loss, received power, and scale from LEO to deep space |
| Sept. 21 | – | No class (Yom Kippur) | No course meeting or deadline |
| Sept. 28 | 3 | Antennas and Pointing | Aperture, gain, beamwidth, pointing loss, mass, coverage, and EIRP trades |
| Oct. 5 | 4 | Optical Communications | RF-versus-optical trades; pointing, acquisition and tracking; atmospheric availability; ground diversity |
| Oct. 12 | – | No class (Fall Break) | University break |
| Oct. 19 | 5 | Noise, G/T, and the Complete Link Budget | Noise temperature, G/T, received energy, margin, and a complete link budget |
| Oct. 26 | 6 | Signals, Modulation, and Bandwidth | Data rate, bandwidth, power efficiency, implementation complexity, and waveform trades |
| Nov. 2 | 7 | Demodulation, BER, and Coding | Coding overhead and gain; trades among EIRP, rate, margin, and reliability |
| Nov. 9 | 8 | Multiple Access, Crosslinks, and Relays | Shared resources, access, relays, crosslinks, capacity, bottlenecks, and scheduling |
| Nov. 16 | 9 | Coverage and Availability | Contact data, availability, outage duration, diversity, and operations |
| Nov. 23 | 10 | Spacecraft Data Services and End-to-End Data Flow | Packetization, buffering, service boundaries, and end-to-end data movement |
| Nov. 30 | 11 | Routing, Store-and-Forward, and DTN | Contact schedules, intermittent routing, latency, custody, delivery, and interoperability |
| Dec. 7 | 12 | Interoperable Space Networks and Architecture Studio | LunaNet and multi-provider networks; integrate links, coverage, delivery, resilience, complexity, and cost. Final-project studio |
Schedule as delivered
- The syllabus says topics and dates “may shift modestly as the lecture materials are rebuilt”
- In practice the Oct. 5 class covered Noise and the Complete Link Budget and the Oct. 19 class covered Signals, Modulation, and Bandwidth (dates from the title slides); optical communications has not been covered yet
Homework
- Number, topics, and timing may change as the class develops; posted on ELMS with reasonable notice
- Deadlines never depend on live attendance
- After feedback, revise and resubmit until correct
- Homework 1 extends the Class 1 lunar orbiter example:
- Daily data volume
- Contact time and ideal payload rate
- Capacity and timeliness
- Due September 14 before class; show calculations and units; revise until correct
What I Will Look For in Your Work
- Show the reasoning. A numerical answer without assumptions, units, or interpretation is incomplete
- Use judgment. When a choice is required, identify the trade and explain why the selection fits the mission
- Check plausibility. Use dimensional analysis, order-of-magnitude checks, and comparison cases
- Document tools. Spreadsheets, scripts, and AI-assisted work must be understandable, reproducible, and consistent with the assignment’s allowed-collaboration rules
- Design end to end. A link that closes is necessary, but not sufficient if coverage, data flow, latency, operations, or interoperability fail
Materials and Tools
- Lecture slides, worked examples, homework templates, reference data, and analysis tools are distributed through ELMS
- No required or recommended readings at the start; occasional readings may be shared
- Office hours announced on ELMS
- Expect to use a spreadsheet and, when supplied, a guided notebook or similar analysis tool
- Programming is not itself a course objective
Policies
- Collaboration and AI: rules are stated on each assignment
- Discussing concepts and approaches may be encouraged, but submitted calculations, explanations, and design choices must represent your own understanding
- Generative AI use must follow the assignment-specific instructions and must not replace your ability to explain or defend the work
- Attendance, absences, and religious observance: attendance is not graded
- Being in class (campus section) makes it easier to work through examples and ask questions
- Let the instructor know promptly about excused absences or religious observances so a reasonable plan can be made without academic penalty