Communication / Ground Link
Line-of-Sight Communication
Decide whether a satellite is visible from a chosen ground station above a minimum elevation, and read a teaching-grade contact-duration label.
- Time estimate
- 20–25 min
- Complexity
- developing
- Maturity
- pilot ready
- Simulator readiness
- implemented
- Software available now
- Implemented — interactive line-of-sight + minimum-elevation teaching lab at `/twin/learn/activities/comm_line_of_sight_basics`. Not orbit propagation, not licensed link planning.
Student path
- Pick a ground station, pass scenario, and minimum elevation angle.
- Read the visible / marginal / not visible verdict and the reason.
- Note the approximate contact-duration label and what it means for operations.
- Copy/export evidence — local-only, teaching geometry, not orbit propagation.
Learning outcomes
Student can explain why ground-station contact depends on satellite visibility above the horizon and on a minimum elevation angle.
- Explain the line-of-sight requirement for ground-station contact.
- Describe how a higher minimum elevation angle shortens or eliminates a pass.
- Connect contact duration to operational planning (uplink commands, downlink data).
Concept primer
Decide whether a satellite is visible from a chosen ground station above a minimum elevation, and read a teaching-grade contact-duration label.
Open the Line-of-Sight Communication lab at `/twin/learn/activities/comm_line_of_sight_basics` — browser-local teaching model (not orbit propagation, not licensed link planning).
Sketch a side-view of Earth, ground station, and satellite at three positions; mark which positions are above a 10° horizon mask.
Interactive lab
Teaching-grade software activity slot — not a flight simulator or certified propagator.
Interactive lab
Line-of-sight contact (teaching)
Choose a ground station, a satellite pass scenario, and a minimum elevation angle. The teaching model returns a visible / marginal / not visible verdict and an approximate contact-duration label. Not orbit propagation, not licensed link planning.
Pass geometry (teaching)
- Pass max elevation
- 85°
- Nominal pass duration
- 9 min
- Minimum elevation mask
- 10°
Visibility verdict
Visible
Pass climbs well above the 10° mask — solid line of sight for most of the pass geometry.
Approx. contact: 8.9 min (long)
Long contact — the best window of the day for downlinking payload backlog.
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: Why does a CubeSat usually see a single ground station only briefly per orbit?
Quick check: Raising the minimum elevation angle from 5° to 20° usually…
Discussion prompt
Short answer (local only)
Write notes for yourself or your group. Nothing is submitted.
Short answer: Pick the pass scenario in this lab where contact was shortest and explain why.
Checklist
Local checklist self-check
Use this to verify you covered key ideas. Nothing is submitted.
Checklist: Line-of-sight readiness (self-check)
0 / 4 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 / 4 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
- Ground station preset: Mid-latitude station
- Pass scenario: High-overhead pass (good geometry)
- Minimum elevation mask: 10°
Generated outputs
- Pass max elevation (preset): 85°
- Nominal pass duration (preset): 9 min
- Visibility verdict: visible
- Reason: Pass climbs well above the 10° mask — solid line of sight for most of the pass geometry.
- Approx. usable contact: 8.9 min
- Contact-duration label: long
Checklist
Evidence checklist
0/4 checked
Evidence artifact (local-only)
Line-of-Sight Communication
Captured: 2026-05-16T07:38:33.072Z · Level: high_school · Track: communication_ground_link
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: Line-of-Sight Communication Track: communication_ground_link Learner level: high_school Captured: 2026-05-16T07:38:33.072Z Mission brief: Teaching geometry of ground-station visibility and minimum-elevation masks (not orbit propagation, not licensed link planning). Selected inputs: - Ground station preset: Mid-latitude station - Pass scenario: High-overhead pass (good geometry) - Minimum elevation mask: 10° Generated outputs: - Pass max elevation (preset): 85° - Nominal pass duration (preset): 9 min - Visibility verdict: visible - Reason: Pass climbs well above the 10° mask — solid line of sight for most of the pass geometry. - Approx. usable contact: 8.9 min - Contact-duration label: long Checklist: - [ ] Picked a ground station, pass scenario, and minimum elevation - [ ] Read the visible / marginal / not visible verdict - [ ] Recorded the approximate contact duration label - [ ] Treated this as teaching geometry, not real pass prediction Observations: (not provided) Reflection: Why this pass scenario is short / long enough for a useful contact. Model boundary note: Local-only teaching model — not a certified RF link budget, not ITU/regulatory analysis, not licensed radio operations, not real satellite command, no SDR or remote hardware. 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).
- Ground station + pass scenario + minimum elevation chosen
- Visible / not visible result with reason (below horizon / low elevation / good pass)
- Approximate contact-duration label
- Local self-check summary and copied evidence text
Reflection
Pick a ground station preset, choose a satellite pass scenario, and adjust the minimum elevation angle; observe whether contact is possible and approximate duration.
Responses are not persisted in this preview unless a specific activity component adds storage later.
Assessment / quick check
Why does a ground station only see a CubeSat for a short window each pass, and why does minimum elevation matter?
Teacher notes
Stress that contact is not continuous — a CubeSat sees most ground stations only during short passes when the satellite is above the horizon at sufficient elevation.
Teacher use
Anchor on line of sight + minimum elevation: a CubeSat is only “visible” when it is above the horizon at sufficient elevation. Stress that this lab is teaching geometry — not orbit propagation, not a licensed link plan.
Next activity
Suggested progression from the mission learning path. Links avoid missing activity routes.