Launch, Gravity & Orbit Basics
Orbit Speed and Altitude
Connect altitude, orbital speed, and period with grade-appropriate math — estimates, not STK-grade precision.
- Time estimate
- 25–30 min
- Complexity
- developing
- Maturity
- pilot ready
- Simulator readiness
- implemented
- Software available now
- Implemented as Altitude–Speed–Period Calculator — interactive activity on `/twin/learn/activities/orbit_speed_and_altitude`.
Student flow
1) Choose altitude
2) Compare cases
3) Explain trend
Evidence and self-check are local-only. Copy/export or screenshot if you want to share.
Learning outcomes
Student can estimate how period and speed change when altitude changes and compare two LEO cases.
- State the approximate orbital speed for LEO.
- Use a simplified formula to estimate orbital period at two different altitudes.
- Explain why lower orbit means shorter period and more passes per day.
Concept primer
Connect altitude, orbital speed, and period with grade-appropriate math — estimates, not STK-grade precision.
Open the Altitude–Speed–Period Calculator at `/twin/learn/activities/orbit_speed_and_altitude` — interactive circular-orbit teaching math and charts (educational model).
Show calculation steps for period from a simplified model; compare to template numbers within stated assumptions.
Interactive lab
Teaching-grade software activity slot — not a flight simulator or certified propagator.
Altitude vs period (circular)
v = 7.589 km/s
T = 95.5 min
Orbits/day ≈ 15.08
Horizon arc (5° el. mask, teaching): 36.0°
| Case | Alt (km) | T (min) |
|---|---|---|
| Current | 550 | 95.5 |
| Lower | 350 | 91.4 |
| Higher | 750 | 99.7 |
One-sentence trend: as altitude increases, orbital period increases (bigger circle) and circular speed decreases slightly — compare the table rows.
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: For circular orbits, what usually happens when altitude increases?
Quick check: Why does orbital period increase at higher altitude (circular) in plain language?
Discussion prompt
Short answer (local only)
Write notes for yourself or your group. Nothing is submitted.
Short answer: Compare two altitudes you tried. What changed, and what stayed roughly the same?
Checklist
Local checklist self-check
Use this to verify you covered key ideas. Nothing is submitted.
Checklist: I can interpret the altitude calculator outputs
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
- Selected altitude: 550 km
- Comparison: Lower 350 km vs higher 750 km
Generated outputs
- Circular speed: 7.589 km/s
- Period: 95.5 min
- Orbits per day: 15.08
- Horizon arc (5° mask): 36.0° (teaching)
- Trend: Higher altitude → longer period and slightly lower speed (circular orbit).
Checklist
Evidence checklist
0/4 checked
Evidence artifact (local-only)
Orbit Speed and Altitude
Captured: 2026-05-16T07:38:32.449Z · 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: Orbit Speed and Altitude Track: launch_gravity_orbit Learner level: middle_school Captured: 2026-05-16T07:38:32.449Z Mission brief: Use a circular-orbit teaching calculator to connect altitude to speed and period (estimates, not operational truth). Selected inputs: - Selected altitude: 550 km - Comparison: Lower 350 km vs higher 750 km Generated outputs: - Circular speed: 7.589 km/s - Period: 95.5 min - Orbits per day: 15.08 - Horizon arc (5° mask): 36.0° (teaching) - Trend: Higher altitude → longer period and slightly lower speed (circular orbit). Checklist: - [ ] I recorded altitude, speed, and period from the tool. - [ ] I compared a lower vs higher altitude case. - [ ] I wrote a one-sentence trend explanation. - [ ] I used “estimate / teaching model” language (not operational 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).
- Altitude selected and recorded
- Speed (km/s) and period (min) from the calculator
- One-sentence explanation of altitude vs period trend
Reflection
Use a provided table or simplified formula; compare 400 km vs 600 km circular orbits.
Responses are not persisted in this preview unless a specific activity component adds storage later.
Assessment / quick check
If you raise orbit altitude, does period usually increase or decrease? Why, in one sentence tied to path length and speed?
Teacher notes
Emphasize “estimate and reason” over memorizing exact km/s; disclose simplifying assumptions.
Teacher guide
Orbit Speed and Altitude
Use this block as facilitation guidance. There is no roster, submission, or teacher visibility workflow in this phase — evidence is shared manually.
Facilitation moves
- Emphasize “estimate and reason” rather than memorizing exact km/s.
- Use the table to compare two altitudes and defend the trend.
- Ask: “What changes more: speed or period? Why?”
Misconceptions to watch for
Higher orbit always means faster.
For circular orbits, speed generally decreases with altitude while period increases (teaching model).
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.