Space Technology
Orbits, launch and the services satellites provide.
Course
Start here. Why things stay in orbit, how rockets get them there, and how satellites shape weather forecasts, navigation, communication and disaster response.
Before you start
- School arithmetic: ratios, percentages and unit conversion
- Reading a simple graph
- No coding or physics background needed
Learning objectives
- Explain an orbit as falling around the Earth while moving sideways fast enough to keep missing it
- Compare low, medium and geostationary orbits by height and by what they are used for
- Name four services satellites provide and trace one of them to something you used today
- Describe why rockets use stages
By the end you can
- Can explain what keeps a satellite in orbit without the word 'gravity-free'
- Can choose a sensible orbit for a familiar service and say why
Before you start
- Newton's laws and circular motion
- Algebra with powers, roots and logarithms
- Spreadsheet basics
Learning objectives
- Derive circular orbital speed by setting gravitational force equal to the centripetal force needed
- Calculate orbital period at any altitude and find the altitude of a 24-hour orbit
- Use the rocket equation to explain why staging improves achievable Δv
- Reason about coverage, revisit time and signal latency when choosing an orbit
By the end you can
- Can derive and apply the circular-orbit relations
- Can defend an orbit choice with numbers rather than adjectives
Lesson plan
Lessons · Ages 14–16
Where space begins
- The 100 km Kármán line as a convention
- Air, vacuum and why satellites fly above the atmosphere
Orbits as falling
- Newton's cannonball thought experiment
- Orbital speed and period
- Low, medium and geostationary orbits
Satellites in daily life
- Navigation and timing
- Weather and Earth observation
- Communication and broadcasting
- Disaster response
Getting to orbit
- Thrust and weight
- Why rockets drop stages
- Launch, separation and deployment
People in orbit
- Space stations
- Life support basics
- Why microgravity research matters
Hands-on activities
- Map one day of your life: list each moment a satellite service helped you (maps, weather, a live broadcast)
- Swing a ball on a string to feel why a faster sideways speed is needed for a tighter orbit
- Use a public satellite pass-prediction website to find when the International Space Station passes over your town
Challenge: Orbit Match
Six satellite services are shown. Match each one to the orbit that suits it best and give a one-line reason.
Pass criteria
- At least 5 of 6 matches correct
- Every match has a reason that mentions height, coverage or how often the satellite passes
Physics and mathematics
Show the 3 equations
v = d ÷ t
v in km/s, d in km, t in s
One trip around a 6,771 km-radius orbit is about 42,500 km. Dividing by the time the trip takes gives the orbital speed.
d = 2 × π × r
r in km (Earth radius 6,371 km + altitude)
The orbit's radius is measured from Earth's centre, not from the ground.
T = 2π × √(r³ ÷ μ)
T in s, r in km, μ = 398,600 km³/s² for Earth
At 400 km altitude this gives about 92 minutes: roughly 15–16 orbits a day.
3D models
- Earth with low, medium and geostationary orbit rings (planned for Academy)
- Space station overview (existing: Space Station tutorial)
Lessons · Ages 17–18
Gravity and circular orbits
- Newton's law of gravitation
- Deriving v = √(μ/r)
- Kepler's third law
Orbit families
- LEO, MEO, GEO and sun-synchronous orbits
- Ground tracks and revisit
- Coverage versus resolution
Launch and Δv
- Tsiolkovsky rocket equation
- Mass ratio and specific impulse
- Why staging helps
The space environment
- Vacuum and outgassing
- Thermal extremes in sunlight and shadow
- Radiation and debris
Hands-on activities
- Build a spreadsheet of period against altitude from 200 km to 40,000 km and find where the period equals one sidereal day
- Compare round-trip signal delay for a low-orbit and a geostationary link and relate it to a video call
- Estimate Δv for a single-stage and a two-stage vehicle with the same total mass and propellant
Challenge: Orbit Brief
Given two missions (low-latency internet and full-disc weather imaging), recommend an orbit for each and support it with calculations.
Pass criteria
- Periods calculated within 2% of the reference values
- Each recommendation addresses coverage, revisit and latency
- Assumptions are stated
Physics and mathematics
Show the 4 equations
v = √(μ ÷ r)
v in km/s, μ = 398,600 km³/s², r in km
From G·M·m/r² = m·v²/r. Higher orbits are slower.
T = 2π × √(r³ ÷ μ)
T in s
Kepler's third law for a circular orbit: period grows with r to the power 1.5.
Δv = Isp × g₀ × ln(m₀ ÷ m_f)
Δv in m/s, Isp in s, g₀ = 9.81 m/s², masses in kg
Δv depends on the logarithm of the mass ratio, which is why dropping empty tanks (staging) pays off.
t = 2h ÷ c
t in s, h in km, c ≈ 300,000 km/s
Up and back down for a satellite directly overhead: milliseconds from low orbit, about a quarter of a second via geostationary orbit.
3D models
- Orbit visualiser with an altitude slider (planned for Academy)
- Two-stage launcher in exploded view (planned for Academy)
Classes and workshops
Online
Self-paced reading and tutorials now; live online classes planned.
In person
No offline workshop is planned for this track yet; its activities can be done at home or in a school lab.
Existing tutorials for this track
Eligibility, independence and privacy
- Independent initiative. Space Academy is part of an independent ISHAVASYAM.ORG education initiative. It is not affiliated with, endorsed by, or run on behalf of ISRO, IN-SPACe, NSIL or the Department of Space.
- No competition eligibility. Learning here does not register anyone for, or make anyone eligible for, any national or international competition. Each competition's organisers set its rules and eligibility.
- Simulated and illustrative. Interactive missions use simplified models and simulated, illustrative values. They are labelled as such and are not flight data.
- Ages. Written for learners aged 14 to 18. Anyone may play the self-paced missions; enquiries from under-18s need a parent or guardian.
- Privacy. Missions never ask for a name, school, age or contact details. Progress is stored only in this browser and can be cleared at any time. This site uses Google Analytics to count page visits and mission steps. Some of the site's existing tutorials ask visitors to sign in with a Google account. If you are under 18, check with a parent or guardian before signing in.