Stella Academy

Stella’s journey

Five missions and 31 lessons, from your first number skills to reading the light of distant stars. Follow them in order, or jump in wherever suits you.

Mission 1 of 5

Build your toolkit

The number skills every other mission relies on.

How the mission connects: Before a rocket leaves the ground, engineers have to size its propellant tanks, mix fuel in the right ratio, read sub-zero gauges and convert every measurement into matching units. These eleven lessons build the number and measurement skills that every later mission uses.

  1. Step 1, Key stage 2, 10 minOrder of Operations (BIDMAS)Every flight formula combines brackets, powers, multiplication and addition: doing them in the agreed order (BIDMAS) stops two engineers getting two different answers from the same equation.Up next
  2. Step 2, Key stage 3, 10 minNegative NumbersCountdown timers run from −10 s through 0 to lift-off, and temperatures in space drop well below 0 °C, so you need negative numbers before you leave the pad.
  3. Step 3, Key stage 2, 10 minLong MultiplicationA rocket burns hundreds of kilograms of propellant every second for several minutes: long multiplication works out the total fuel mass needed for the burn.
  4. Step 4, Key stage 2, 10 minFractions and ProportionsMost of a rocket on the launchpad is propellant: fractions describe what share of the total launch mass is fuel and what share is left for the spacecraft and crew.
  5. Step 5, Key stage 2, 15 minCalculating with FractionsAs stages burn and separate, you add, subtract and multiply fractions of the tank and total mass to track how much propellant remains.
  6. Step 6, Key stage 2, 10 minFractions, Decimals and PercentagesCockpit displays and engineering sheets report tank levels, engine efficiency and safety margins as decimals and percentages.
  7. Step 7, Key stage 3, 15 minRatio and ProportionRocket engines mix liquid oxygen and fuel in a fixed ratio, and scale models in wind tunnels rely on proportion to predict full-size forces.
  8. Step 8, Key stage 2, 12 minArea and PerimeterSolar panels collect power in proportion to their surface area, while thermal seals run around the perimeter of hatches and windows.
  9. Step 9, Key stage 2, 15 minVolume of Cubes and CuboidsPropellant tanks, cargo bays and pressurised crew modules are three-dimensional spaces: volume tells you how much fuel or air they can hold.
  10. Step 10, Key stage 3, 15 minPowers and RootsDistances in space and energies in physics span huge ranges, so powers, square roots and standard form let you write 384,000,000 m without losing a zero.
  11. Step 11, Key stage 2, 15 minMeasures and Converting UnitsDrawings, fuel gauges and maps use millimetres, metres, kilometres, kilograms and litres: converting cleanly between units prepares you for physics formulas.

Mission 2 of 5

Get to orbit

What it takes to leave the ground and stay up.

How the mission connects: Getting to space is a chain of physical steps: keep every calculation in consistent SI units, use gears to steer heavy nozzles, burn hot high-pressure gas to throw exhaust backward for momentum, balance Earth’s gravity in a circular orbit, and fire two timed burns to transfer to a higher orbit.

  1. Step 1, GCSE, 15 minConverting UnitsPhysics equations only work when every quantity is in compatible SI units: a mix-up between pound-seconds and newton-seconds famously lost the Mars Climate Orbiter.Up next
  2. Step 2, GCSE, 10 minGears and Gear RatiosBefore launch, small electric motors must swing heavy rocket nozzles, fuel valves and solar wings into place: gears trade rotation speed for turning force (moment).
  3. Step 3, GCSE, 15 minMomentum and CollisionsIn the vacuum of space there is no air to push against: a rocket accelerates forward by throwing hot exhaust gas backward and conserving total momentum.
  4. Step 4, A-level, 20 minThermodynamics and the Ideal Gas LawHow do you throw exhaust gas out at 3,000 m/s? Burning propellant in a combustion chamber creates a hot, high-pressure gas (pV = nRT) that expands through the nozzle.
  5. Step 5, A-level, 15 minGravity and Newton's Law of GravitationOnce above the atmosphere, Earth’s gravity (F = GMm/r²) pulls the spacecraft inward: if its sideways speed matches the curve of the Earth, it stays in orbit.
  6. Step 6, A-level, 20 minOrbits and Hohmann TransfersTo climb from a low parking orbit to a higher target orbit using the least fuel, the spacecraft fires its engine twice along an elliptical Hohmann transfer.

Mission 4 of 5

Talk to the spacecraft

How a spacecraft is powered, and how it sends word home.

How the mission connects: A probe millions of kilometres away is only useful if it can send its findings home. Electrical circuits power the onboard instruments, radio waves carry the signal across empty space, binary 1s and 0s protect pictures and telemetry from radio static, and parallel backup probability keeps the computer running if a part fails.

  1. Step 1, GCSE, 10 minOhm's Law: Voltage, Current and ResistanceBefore the spacecraft can send a single message, solar arrays and batteries must drive the right current through its sensors and radio transmitter (V = IR).Up next
  2. Step 2, GCSE, 15 minWaves: Frequency, Wavelength and SpeedSound cannot cross a vacuum, so the transmitter radiates electromagnetic radio waves (v = fλ) tuned to a chosen frequency and wavelength to reach Earth.
  3. Step 3, Key stage 3, 15 minBinary NumbersAcross millions of kilometres a radio wave grows faint and noisy: encoding every camera pixel and sensor reading as binary 1s and 0s (on/off pulses) lets Earth reconstruct the message cleanly through static.
  4. Step 4, GCSE, 15 minProbabilityCosmic rays and harsh conditions can still cause a component to fail, so engineers use probability to design parallel backup computers that keep the mission alive.

Mission 5 of 5

Read the starlight

What light and data tell us about things too far away to visit.

How the mission connects: Even our fastest probes cannot reach other stars, so we read the light that travels to us. Refraction splits starlight into a spectrum, statistics separates real signals from sensor noise, electromagnetism explains how fields and waves interact, and quantum photon energy reveals what distant stars are made of.

  1. Step 1, GCSE, 15 minRefraction and Snell's LawWe cannot visit distant stars, so we bend their light through a prism or grating: refraction (Snell’s law) spreads starlight into a spectrum of wavelengths.Up next
  2. Step 2, A-level, 15 minMean, Variance and Standard DeviationEvery telescope and detector has random noise: mean, variance and standard deviation separate a real stellar signal from background scatter.
  3. Step 3, A-level, 20 minElectromagnetic Induction and Faraday's LawChanging magnetic fields induce voltages in coils (Faraday’s law), both in spacecraft generators and in the electromagnetic waves arriving from space.
  4. Step 4, A-level, 25 minPhotons and Quantum PhysicsAt the detector, starlight arrives as individual photons (E = hf): each photon’s frequency tells us its exact energy and reveals which atoms emitted it.

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