CubeSTEM Digital Twin · Track 1
Track 1 — Launch, Gravity, and Orbit
A five-activity mini-course that builds orbit intuition: free-fall + sideways velocity, altitude vs speed/period, orbit-class trade-offs, ground track/coverage, and contact windows.
Local-only mini-course: no account, no submissions, no gradebook. Teaching-grade orbit models — not a certified propagator; not STK/GMAT.
What this mini-course teaches
Understand how satellites reach orbit and how altitude, speed, and contact windows work.
Mini-course flow
Five activities, in order
Each activity is implemented as browser-based interactive software. Evidence and self-checks are local-only — copy, export, or screenshot if you want to share.
Recommended pacing: treat each activity as one session, then follow the “Next” step inside the activity page to continue the sequence.
Session 1
From Launch to Orbit
Time estimate: 20–25 min
Learning goal: Student explains orbit as continuous free fall: gravity plus sideways velocity, not “no gravity.”
Expected evidence (local)
- Speed factor selected in the visualizer
- Observed path class (falls back / near orbit / escape-like)
- Evidence summary copied with gravity-inward, velocity-sideways, free-fall checklist
Session 2
Orbit Speed and Altitude
Time estimate: 25–30 min
Learning goal: Student can estimate how period and speed change when altitude changes and compare two LEO cases.
Expected evidence (local)
- Altitude selected and recorded
- Speed (km/s) and period (min) from the calculator
- One-sentence explanation of altitude vs period trend
Session 3
Low Earth Orbit vs Higher Orbit
Time estimate: 20–25 min
Learning goal: Student can describe at least two trade-offs between LEO and GEO (or MEO) for a CubeSat-class mission.
Expected evidence (local)
- Orbit class selected
- Two advantages and two disadvantages stated
- Short mission justification for a stated goal
Session 4
Ground Track and Coverage
Time estimate: 20–25 min
Learning goal: Student can explain ground track, inclination, and why revisits happen faster in LEO than in distant orbits.
Expected evidence (local)
- Inclination and max latitude coverage recorded
- Observation of ground track on the map (screenshot or description)
- Short explanation of why inclination matters for coverage
Session 5
Contact Window Basics
Time estimate: 20 min
Learning goal: Student can explain line-of-sight, why passes are brief, and how that limits downlink time.
Expected evidence (local)
- Ground station selected
- Passes and total contact time recorded
- Whether data backlog occurs in the toy model
Teacher plan
Track 1 mini-course (facilitated, local-only)
Use this pack to teach orbit fundamentals as a coherent mini-course. Evidence and self-check are local-only (copy/export/screenshot) — no submissions, rosters, or gradebook.
45-minute orbit demo
45 min
- 5 min: orbit misconception reset (gravity is still present) + local-only boundary.
- 18–20 min: Activity 1.1 From Launch to Orbit (whole class).
- 10 min: Activity 1.2 Altitude vs period trend (pairs compare two altitudes).
- 8–10 min: Activity 1.5 Contact window basics + one mitigation exit ticket.
90-minute class/lab
90 min
- 10 min: vocabulary + boundary (teaching-grade; not STK/GMAT; no submissions).
- 25 min: Activity 1.1 + evidence capture.
- 25 min: Activity 1.4 Ground track/coverage (inclination → max latitude).
- 20 min: Activity 1.5 Contact window + backlog story; discuss mitigations.
- 10 min: local self-check prompts + compare evidence artifacts (manual share).
Half-day workshop
3–4 hours
- Run all five activities in order with short debriefs after each.
- Add an ‘orbit choice’ discussion: revisit, latency, coverage, and ops impacts.
- Include a gallery walk: teams compare exported evidence artifacts (manual share).
- End with the Track 2 bridge: mission objective → payload → constraints (overview only).
Bridge — Mission Realism Lab
Apply this with contact windows and coverage in Mission Realism Lab.
Common misconceptions (Track 1)
Orbit means there is no gravity.
In orbit, gravity is still strong. The spacecraft is in continuous free-fall with high sideways velocity, so it keeps “missing” Earth.
Satellites are floating — not falling.
Satellites are falling the entire time. They keep falling around Earth because their sideways velocity carries them forward as gravity pulls inward.
Higher orbit always means faster speed.
For circular orbits, speed generally decreases with altitude while period increases. (There are exceptions in elliptical transfer cases, but those are out of scope here.)
A ground station can talk to the satellite all the time.
Contact windows are brief line-of-sight periods. Operators schedule commands and downlinks around passes.
Teaching orbit tools are the same as STK/GMAT or flight dynamics software.
These routes are designed for conceptual understanding and bounded estimates. They are not certified mission analysis tools or operational propagators.
Facilitation prompts (use across activities)
- Ask: “If gravity pulls inward, what keeps the satellite from hitting Earth immediately?”
- Ask: “What changes when altitude changes: speed, period, and contact frequency?”
- Ask: “What does inclination tell you about who can be served on Earth?”
- Prompt: “Make one claim, then point to the evidence artifact that supports it.”
Expected evidence (by activity)
From Launch to Orbit
Time estimate: 20–25 min
Assessment prompt: Why doesn’t the satellite fall straight down to Earth even though gravity pulls it toward Earth?
- Speed factor selected in the visualizer
- Observed path class (falls back / near orbit / escape-like)
- Evidence summary copied with gravity-inward, velocity-sideways, free-fall checklist
Orbit Speed and Altitude
Time estimate: 25–30 min
Assessment prompt: If you raise orbit altitude, does period usually increase or decrease? Why, in one sentence tied to path length and speed?
- Altitude selected and recorded
- Speed (km/s) and period (min) from the calculator
- One-sentence explanation of altitude vs period trend
Low Earth Orbit vs Higher Orbit
Time estimate: 20–25 min
Assessment prompt: Name one mission goal that favors LEO and one that might favor a higher orbit — and what cost or constraint comes with the higher orbit.
- Orbit class selected
- Two advantages and two disadvantages stated
- Short mission justification for a stated goal
Ground Track and Coverage
Time estimate: 20–25 min
Assessment prompt: What does orbital inclination tell you about which parts of Earth the mission can see over time?
- Inclination and max latitude coverage recorded
- Observation of ground track on the map (screenshot or description)
- Short explanation of why inclination matters for coverage
Contact Window Basics
Time estimate: 20 min
Assessment prompt: Why can’t the ground station talk to the satellite all the time, even if both are powered on?
- Ground station selected
- Passes and total contact time recorded
- Whether data backlog occurs in the toy model
- One mitigation (lower data rate, higher downlink, more stations, or prioritize data)
Boundary reminder: local-only learning experience (no accounts, no submissions, no grades), and teaching-grade orbit models (not a certified propagator; not STK/GMAT).
Student path
What to do, step by step
This is a guided path, not a submission system. Your evidence and self-check stay in your browser unless you copy/export or screenshot it to share manually.
Tip: after each activity, use the Evidence panel to copy/export your summary before moving on.
Step 1
From Launch to Orbit
Time estimate: 20–25 min
- Move the speed factor slider and run/reset a few times.
- Describe the outcome using precise language: gravity pulls inward + velocity is sideways → free fall.
- Capture evidence: speed factor + path class + 1–2 sentence explanation.
Step 2
Orbit Speed and Altitude
Time estimate: 25–30 min
- Choose an altitude and record the displayed speed and period (teaching estimate).
- Compare a lower vs higher altitude case; write one trend sentence.
- Capture evidence: altitude + speed + period + trend explanation.
Step 3
Low Earth Orbit vs Higher Orbit
Time estimate: 20–25 min
- Select an orbit class preset and compare trade-offs (revisit/latency/difficulty).
- Write 2 pros + 2 cons and justify which class fits a stated mission goal.
- Capture evidence: chosen class + justification.
Step 4
Ground Track and Coverage
Time estimate: 20–25 min
- Adjust inclination and observe the max latitude band and ground track.
- Explain the latitude ceiling in one sentence (|lat| ≤ inclination).
- Capture evidence: inclination + max latitude + one ground-track observation.
Step 5
Contact Window Basics
Time estimate: 20 min
- Pick a station and scenario; observe passes and total contact time.
- Compare generated vs downlinked data in the toy estimate; note backlog yes/no.
- Write one mitigation idea (rate, more stations, prioritization).
- Capture evidence: station + contact time + backlog + mitigation.
Bridge — Mission Realism Lab
Apply this with contact windows and coverage in Mission Realism Lab.
After Track 1
Continue into Track 2 — Mission Design / Payload Thinking. The mini-course turns a vague idea into a testable mission, connects payload to subsystem needs, estimates payload data vs downlink, and defines measurable success criteria. The Mission Design Lab is the optional planning surface alongside it.
Evidence checklist
What to capture (local-only)
Evidence artifacts are local-only. There is no submission or teacher visibility workflow — copy/export (text+JSON) or screenshot to share manually.
From Launch to Orbit
⏱ 20–25 min
- Speed factor selected in the visualizer
- Observed path class (falls back / near orbit / escape-like)
- Evidence summary copied with gravity-inward, velocity-sideways, free-fall checklist
Reflection prompt: Why doesn’t the satellite fall straight down to Earth even though gravity pulls it toward Earth?
Orbit Speed and Altitude
⏱ 25–30 min
- Altitude selected and recorded
- Speed (km/s) and period (min) from the calculator
- One-sentence explanation of altitude vs period trend
Reflection prompt: If you raise orbit altitude, does period usually increase or decrease? Why, in one sentence tied to path length and speed?
Low Earth Orbit vs Higher Orbit
⏱ 20–25 min
- Orbit class selected
- Two advantages and two disadvantages stated
- Short mission justification for a stated goal
Reflection prompt: Name one mission goal that favors LEO and one that might favor a higher orbit — and what cost or constraint comes with the higher orbit.
Ground Track and Coverage
⏱ 20–25 min
- 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 prompt: What does orbital inclination tell you about which parts of Earth the mission can see over time?
Contact Window Basics
⏱ 20 min
- Ground station selected
- Passes and total contact time recorded
- Whether data backlog occurs in the toy model
- One mitigation (lower data rate, higher downlink, more stations, or prioritize data)
Reflection prompt: Why can’t the ground station talk to the satellite all the time, even if both are powered on?
Boundary reminder: teaching-grade orbit models (not a certified propagator; not STK/GMAT) and local-only learning (no accounts, no submissions, not a grade).
Assessment map
Self-check prompts (not a grade)
Use these prompts as a discussion guide or local self-check after each activity. There is no submission pipeline, no gradebook, and no teacher visibility unless learners share evidence manually.
From Launch to Orbit
Time estimate: 20–25 min
Prompt: Why doesn’t the satellite fall straight down to Earth even though gravity pulls it toward Earth?
Look-fors (evidence cues)
- Speed factor selected in the visualizer
- Observed path class (falls back / near orbit / escape-like)
- Evidence summary copied with gravity-inward, velocity-sideways, free-fall checklist
Misconceptions to watch
- “Orbit means no gravity” (correct: gravity is the inward pull; orbit is continuous free-fall + sideways velocity).
- “If it’s moving sideways, gravity stops mattering” (correct: gravity is what bends the path).
Orbit Speed and Altitude
Time estimate: 25–30 min
Prompt: If you raise orbit altitude, does period usually increase or decrease? Why, in one sentence tied to path length and speed?
Look-fors (evidence cues)
- Altitude selected and recorded
- Speed (km/s) and period (min) from the calculator
- One-sentence explanation of altitude vs period trend
Misconceptions to watch
- “Higher altitude always means faster” (correct: for circular orbits, speed generally decreases as altitude increases).
Low Earth Orbit vs Higher Orbit
Time estimate: 20–25 min
Prompt: Name one mission goal that favors LEO and one that might favor a higher orbit — and what cost or constraint comes with the higher orbit.
Look-fors (evidence cues)
- Orbit class selected
- Two advantages and two disadvantages stated
- Short mission justification for a stated goal
Misconceptions to watch
- “One orbit is always best” (correct: orbit class is a mission trade-off: revisit, latency, coverage, ops constraints).
Ground Track and Coverage
Time estimate: 20–25 min
Prompt: What does orbital inclination tell you about which parts of Earth the mission can see over time?
Look-fors (evidence cues)
- Inclination and max latitude coverage recorded
- Observation of ground track on the map (screenshot or description)
- Short explanation of why inclination matters for coverage
Misconceptions to watch
- “Inclination is the same as altitude” (correct: inclination controls latitude reach/coverage pattern).
- “You can see any latitude from any orbit” (correct: max latitude is bounded by inclination in the simplified model).
Contact Window Basics
Time estimate: 20 min
Prompt: Why can’t the ground station talk to the satellite all the time, even if both are powered on?
Look-fors (evidence cues)
- Ground station selected
- Passes and total contact time recorded
- Whether data backlog occurs in the toy model
- One mitigation (lower data rate, higher downlink, more stations, or prioritize data)
Misconceptions to watch
- “Ground stations can talk continuously” (correct: contact windows are brief line-of-sight passes).
Boundary reminder: local self-check only (not a grade) and teaching-grade orbit models (not a certified propagator; not STK/GMAT).
Five activities (quick view)
- From Launch to Orbit — Follow launch to orbit: gravity pulls inward while high sideways speed makes the spacecraft keep “missing” Earth — that is orbit.
- Orbit Speed and Altitude — Connect altitude, orbital speed, and period with grade-appropriate math — estimates, not STK-grade precision.
- Low Earth Orbit vs Higher Orbit — Compare LEO with higher orbits for power, latency, coverage, and what is realistic for a small satellite.
- Ground Track and Coverage — Ground track is the path on Earth under the satellite; inclination sets the latitude “ceiling” of coverage.
- Contact Window Basics — Ground stations only hear the spacecraft when it rises above the horizon — short passes, a few times per day in LEO.
Next step after Track 1
Track 2 — Mission Design & Payload Thinking
After you understand orbit constraints (coverage, contacts, time in view), the next step is mission design: choose an objective, pick a payload, reason about data, and define measurable success criteria. Track 2 is now a four-activity yardstick mini-course with local self-check and copyable evidence.