The year is 2032. After a decade of robotic precursor missions, humanity is finally ready to send a crewed expedition to Mars. You are the lead mission planner for the Ares VII program. Your six crew members will board a rocket capable of carrying them across 225 million kilometers of empty space — but only if you launch in the right window.
Mars and Earth orbit the Sun at different speeds. Earth completes one orbit every 365.26 days, while Mars takes 686.98 days to make the same trip. Because of this difference, the two planets line up favorably only once every 26 months. Miss the window, and the trip becomes much longer and requires far more fuel.
Engineers use a maneuver called a Hohmann transfer orbit — an elliptical path that touches Earth's orbit at one end and Mars's orbit at the other. This transfer is the most fuel-efficient route, taking roughly 7 months (about 210 days) one way. Crew members must survive that voyage in cramped quarters, exposed to cosmic radiation, while their bones and muscles weaken in microgravity.
Mars itself is a hostile world. The atmosphere is just 0.6% of Earth's pressure — about as thin as the air 30 km above Earth's surface. The average surface temperature is -63 °C, and dust storms occasionally engulf the entire planet. But Mars also has water ice at its poles, a 24.6-hour day length nearly identical to Earth's, and an axial tilt of 25.19° that produces seasons. With careful engineering, it can become humanity's second home.
— Ares VII Mission Control, Houston
Use what you read above. Type your answers in full sentences.
All cards are visible. Click any card to see its definition for 8 seconds. You can re-open any card as many times as you like.
Each crew member has different strengths. Balance your team for the journey ahead.
The synodic period (Earth-Mars alignment cycle) is approximately 780 days (~26 months). Pick your launch year:
The Ares VII rocket carries 1,200 metric tons of fuel. Each ton of cargo requires fuel based on the trajectory. Use the formula:
Fill in the blanks using ESRT page 15 (Solar System Data). Round to two decimal places where needed.
| Planet | Mean Distance from Sun (AU) | Period of Revolution (days) | Eccentricity of Orbit | Equatorial Diameter (km) |
|---|---|---|---|---|
| Venus | 224.7 | 0.007 | ||
| Earth | 1.00 | 0.017 | 12,756 | |
| Mars | 1.52 | 686.98 | 6,792 |
Once Ares VII clears Earth orbit, the crew settles in for a 210-day cruise across the inner solar system. Three threats define the voyage: radiation, microgravity, and distance.
Radiation. Beyond Earth's magnetic field, the crew is exposed to galactic cosmic rays and occasional solar particle events. A single solar flare can deliver a year's worth of radiation in hours. The hab module's water tanks double as shielding — water is excellent at absorbing high-energy particles.
Microgravity. Without gravity, bones lose 1–2% of their mass each month, and muscles atrophy. Crews on the ISS exercise 2.5 hours per day just to slow the loss. Ares VII rotates at 4 rpm to generate artificial gravity equal to about 0.38 g — the same as Mars's surface — so the crew arrives ready to walk.
Distance. As the ship moves farther from the Sun, available solar power drops by the inverse square law: doubling the distance cuts the power to one-quarter. At Mars (1.52 AU), the Sun delivers only 43% of the energy it does at Earth. Solar panels must be larger, and any dust storm that blocks sunlight becomes a survival emergency.
By the time the ship reaches Mars orbit, the crew must already know exactly where they will land. Four candidate sites have been mapped. Each offers different resources, hazards, and scientific value.
— Mission Operations Handbook, §4.3
Click Advance Week to move forward in time. Allocate ship power between three systems. The total must equal 100%. Random events will challenge you.
The graph below shows the percentage of solar power available compared to Earth's level (100%) as the spacecraft travels outward.
Fill in the missing entries by reading the four site cards below. Then choose your landing site.
| Site | Latitude | Water Ice (%) | Avg Temp (°C) | Hazard Level |
|---|---|---|---|---|
| Jezero Crater | 18° N | -65 | Low | |
| Hellas Planitia | 8 | -70 | Medium | |
| Korolev Crater | 73° N | 95 | High | |
| Olympus Base | 18° N | 2 | -58 |
Terraforming Mars means changing it on a planetary scale to support life. Three knobs control the process:
1. Greenhouse gases. Releasing CO₂ from the polar caps and pumping perfluorocarbons into the air thickens the atmosphere and traps heat. Each percentage point of pressure increase is decades of work.
2. Orbital mirrors. Giant reflectors in Mars orbit redirect sunlight onto the poles, accelerating ice sublimation and warming the surface.
3. Biological seeding. Once the atmosphere thickens and liquid water appears, hardy cyanobacteria and lichens can release oxygen — the same process that oxygenated early Earth over 2 billion years.
The goal: surface pressure above 500 mbar, average temperature above 0 °C, and breathable oxygen above 15%. Earth-like conditions are 1013 mbar, 15 °C, and 21% O₂.
— Planetary Engineering Briefing
Adjust the three controls. Each click of Advance 50 Years moves you forward. Reach all three goal thresholds to win.