Launch, Gravity & Orbit Basics
Ground Track and Coverage
Ground track is the path on Earth under the satellite; inclination sets the latitude “ceiling” of coverage.
- Time estimate
- 20–25 min
- Complexity
- developing
- Maturity
- pilot ready
- Simulator readiness
- implemented
- Software available now
- Implemented as Ground Track and Coverage Explorer — interactive activity on `/twin/learn/activities/orbit_ground_track_coverage`.
Student flow
1) Choose inclination
2) Observe track
3) Explain
Evidence and self-check are local-only. Copy/export or screenshot if you want to share.
Learning outcomes
Student can explain ground track, inclination, and why revisits happen faster in LEO than in distant orbits.
- Define orbital inclination and explain its effect on latitude coverage.
- Explain what a ground track is and how many passes per day a LEO satellite makes.
- Connect inclination to regional imaging or communication mission goals.
Concept primer
Ground track is the path on Earth under the satellite; inclination sets the latitude “ceiling” of coverage.
Open the Ground Track and Coverage Explorer at `/twin/learn/activities/orbit_ground_track_coverage` — equirectangular map with circular model; optional sample TLE (SGP4) in university mode (educational TLE only).
Draw ground track swaths; label ascending/descending ideas in plain language.
Interactive lab
Teaching-grade software activity slot — not a flight simulator or certified propagator.
Max latitude reached (|i|): 51.6°
Orbits/day ≈ 15.08
Inclination sets how far north/south the ground track can swing; near-polar orbits touch higher latitudes.
Local self-check
Assessment (practice only)
Use this as a self-check and discussion starter. It is local-only and not a grade.
Optional: attaches a local summary (completed / quick checks / checklist count).
Quick check
Multiple choice self-check
This is a local self-check to support discussion. It is not a grade.
Quick check: In this model, what does inclination most directly control?
Quick check: Why does the ground track shift between orbits?
Discussion prompt
Short answer (local only)
Write notes for yourself or your group. Nothing is submitted.
Short answer: If a mission must cover high latitudes, what inclination choice trend would you expect?
Checklist
Local checklist self-check
Use this to verify you covered key ideas. Nothing is submitted.
Checklist: I can read coverage from the ground track
0 / 3 checked
Local summary
Assessment summary (practice only)
Completion
0 / 4 sections complete
Quick checks
0 / 2 correct
Shown only to support self-check.
Checklist
0 / 3 items checked
Reminder
Local-only practice summary. Not a grade and not submitted anywhere.
What this preview is / is not
Assessment engine v0 boundary note
- Student view (local practice): use this as a self-check and discussion starter.
- Local-only preview/practice: your answers are not submitted.
- No backend, no accounts, no roster, and no LMS integration.
- Not a grade. No credential or official scoring is implied.
- Teacher visibility into student answers is not implemented in MVPF8.
- Evidence runtime engine arrives in Phase 9 (not in this preview).
Capture
Evidence capture (local-only)
Capture what you did, what changed, what you observed, and how you explain it. This stays in your browser unless you copy/share it manually.
Selected inputs
- Altitude: 550 km
- Inclination: 51.6°
- Duration mode: 1 (96 min)
- Mode: Circular teaching ground track
Generated outputs
- Max latitude coverage: ±51.6° (teaching)
- Approx. orbits/day: 15.08 @ 550 km
- Observation: Earth rotates under the orbit, so ground tracks shift between passes (qualitative).
Checklist
Evidence checklist
0/4 checked
Evidence artifact (local-only)
Ground Track and Coverage
Captured: 2026-05-16T07:38:32.669Z · Level: middle_school · Track: launch_gravity_orbit
Summary
Copyable class summary
Copy a readable summary for class notes, or copy JSON for a structured record. Local-only: nothing is submitted.
Evidence artifact (v1) Activity: Ground Track and Coverage Track: launch_gravity_orbit Learner level: middle_school Captured: 2026-05-16T07:38:32.669Z Mission brief: Use a simple ground track explorer to connect inclination to latitude coverage and explain why the track shifts between passes. Selected inputs: - Altitude: 550 km - Inclination: 51.6° - Duration mode: 1 (96 min) - Mode: Circular teaching ground track Generated outputs: - Max latitude coverage: ±51.6° (teaching) - Approx. orbits/day: 15.08 @ 550 km - Observation: Earth rotates under the orbit, so ground tracks shift between passes (qualitative). Checklist: - [ ] I recorded inclination and max latitude coverage. - [ ] I made one observation about the ground track. - [ ] I explained the latitude ceiling in one sentence (|lat| ≤ inclination). - [ ] I used teaching-grade language (map is illustrative, not GIS truth). Observations: (not provided) Reflection: (not provided) Model boundary note: Local-only teaching model. Not a certified propagator; not STK/GMAT. Evidence is not submitted anywhere and is not a grade. Policy reminder: - Local-only capture. Not submitted anywhere. Not a grade.
Evidence capture
Expected outputs learners should be able to show after the lab (Phase 9 evidence engine preview available).
- Inclination and max latitude coverage recorded
- Observation of ground track on the map (screenshot or description)
- Short explanation of why inclination matters for coverage
Reflection
On a globe or map, trace repeated passes and shade latitudes never reached for a given inclination.
Responses are not persisted in this preview unless a specific activity component adds storage later.
Assessment / quick check
What does orbital inclination tell you about which parts of Earth the mission can see over time?
Teacher notes
Pair with Earth science: revisit time, storms, or imaging cadence narratives without claiming GIS product fidelity.
Teacher guide
Ground Track and Coverage
Use this block as facilitation guidance. There is no roster, submission, or teacher visibility workflow in this phase — evidence is shared manually.
Facilitation moves
- Have students predict the latitude ceiling before moving the slider.
- Connect to mission narrative: what regions can be served/imaged over time?
- Keep claims qualitative: map is an illustration, not a certified coverage tool.
Misconceptions to watch for
Emphasize the capability boundary: teaching-grade model, local-only evidence, not a certified propagator.
Boundary reminder: teaching-grade orbit models (not a certified propagator; not STK/GMAT) and local-only learning (no accounts, no submissions, not a grade).
Next activity
Suggested progression from the mission learning path. Links avoid missing activity routes.