Beginner 9 missions

Time and Orbital Period

Learn how orbital period relates to altitude. Understand Kepler's Third Law and how to calculate when you'll arrive somewhere.

12 min Lesson

Circularization

Learn to make perfect circular orbits by matching your periapsis and apoapsis. This essential skill is needed for stable orbits and rendezvous.

12 min Lesson

Basic Orbit Changes

Learn how different burns at different positions affect your orbit. Understand the fundamental principle: you change the opposite side of your orbit.

15 min Lesson

Velocity and Direction

Understand the six cardinal directions in space: prograde, retrograde, normal, anti-normal, radial, and anti-radial. Learn how velocity changes affect your orbit.

12 min Lesson

Understanding Orbits

Learn what an orbit actually is and why objects stay in orbit instead of falling down. Discover the fundamental relationship between velocity and gravity.

10 min Lesson

Lunar Orbit Insertion

Travel from Earth to the Moon and achieve a stable lunar orbit. Your first journey to another celestial body!

12 min Free form

Orbital Energy and Speed

Discover the relationship between orbital energy, speed, and altitude. Learn why you move faster when you're closer to the planet.

12 min Lesson

The Ultimate Optimization

The ultimate challenge: perform a complete mission from Earth to Saturn orbit with an absurdly limited fuel budget. Use every trick in the book - gravity assists, aerobraking, low-energy transfers, and perfect timing.

60 min Optimization

Understanding Apoapsis and Periapsis

Deep dive into the two most important points in your orbit. Learn to use them strategically for efficient maneuvering.

10 min Lesson

Intermediate 10 missions

Station Resupply

Launch from Earth and dock with the International Space Station in its 51.6-degree inclined orbit. Time your launch window correctly and perform a precise rendezvous.

15 min Free form

Delta-V Budgets

Learn to plan missions by calculating total delta-V requirements. Master the art of fuel budgeting for complex multi-stage missions.

15 min Lesson

Emergency Return

Your spacecraft has suffered a malfunction and you need to return to Earth immediately. Perform an emergency de-orbit and atmospheric entry with limited fuel and tight time constraints.

8 min Free form

Solar Sentinel

Establish a Sun-synchronous orbit for an Earth observation satellite. This special orbit keeps your satellite in constant sunlight, perfect for solar-powered imaging missions.

12 min Free form

High Latitude Coverage

Establish a Molniya orbit, a highly elliptical orbit used for communications in high-latitude regions. This orbit provides long dwell time over the northern hemisphere.

10 min Free form

Eccentricity and Orbit Shapes

Master the concept of eccentricity - the number that describes your orbit's shape. Learn to recognize different orbit types by their eccentricity.

15 min Lesson

Asteroid Sample Return

Execute an OSIRIS-REx style mission to a near-Earth asteroid. Rendezvous with asteroid Bennu, match its velocity precisely, perform a touch-and-go sample collection, then return your precious cargo to Earth. Every gram of primordial material is priceless for science.

30 min Free form

Red Planet Rendezvous

Execute a Hohmann transfer from Earth orbit to Mars orbit. Achieve Mars orbit insertion with minimal delta-V expenditure.

15 min Single maneuver

Mars to Ceres Express

Journey from the red planet to the largest object in the asteroid belt. Ceres is a dwarf planet with potential subsurface oceans, making it a prime target for exploration. Execute a direct transfer and achieve orbit insertion around this mysterious world.

25 min Single maneuver

Morning Star Mission

Execute a Hohmann transfer from Earth to Venus. Unlike Mars, Venus is closer to the Sun, requiring a different approach. Achieve Venus orbit insertion on a limited fuel budget.

12 min Single maneuver

Advanced 17 missions

Sideways World Explorer

Journey to Uranus, the tilted ice giant with its unique sideways rotation, and tour its five major moons: Miranda with its extreme terrain, Ariel and Umbriel with their contrasting surfaces, and the larger Titania and Oberon. This 7-9 year mission explores one of the least understood regions of the solar system.

45 min Free form
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Vesta Reconnaissance

Recreate NASA's Dawn mission approach to Vesta, the second-largest asteroid. Use ion propulsion to spiral into three different science orbits, from high survey orbit down to low-altitude mapping. Master the art of continuous low-thrust maneuvering.

35 min Free form
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Lagrange Asteroid Hunters

Journey to Jupiter's Trojan asteroids, trapped in stable orbits at the L4 and L5 Lagrange points. These ancient remnants from the early solar system orbit 60° ahead and behind Jupiter. Visit multiple Trojans in both swarms, inspired by NASA's Lucy mission.

40 min Free form
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Rings and Moons Odyssey

Tour Saturn's magnificent moon system in the tradition of the Cassini mission. Use resonant orbits and gravity assists to visit Titan, Enceladus, Rhea, and Dione efficiently. Each moon reveals new wonders - from Titan's thick atmosphere to Enceladus' icy geysers.

40 min Free form
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Gateway to the Cosmos

Deploy a space telescope at the Sun-Earth L2 Lagrange point, following in the footsteps of James Webb Space Telescope. This gravitationally stable location 1.5 million km from Earth provides an ideal vantage point for observing the universe, with continuous power from the Sun and communication with Earth.

30 min Free form
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Solar Storm Sentinel

Position a solar monitoring satellite at Sun-Earth L1 to provide early warning of space weather. This critical location, 1.5 million km sunward of Earth, offers continuous view of the Sun and 30-60 minutes advance warning of solar storms. Establish and maintain a Lissajous orbit for uninterrupted observations.

25 min Free form
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Dance with the Sun

Intercept a sungrazing comet on its death-defying plunge toward the Sun. These comets pass within a few solar radii of our star's surface, experiencing temperatures over 2000°C. Your spacecraft must survive the intense heat and radiation while collecting priceless data on this cosmic suicide dive.

30 min Free form
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Venus Slingshot

Use Venus' gravity to boost your velocity toward the outer solar system. Master the art of gravity assists by performing a precise flyby of Venus.

20 min Free form
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Journey to the Giant

Execute a Hohmann transfer from Earth to Jupiter, the king of planets. This long-duration mission requires careful planning and fuel management for orbit insertion around this gas giant.

25 min Single maneuver
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Lord of the Rings

Travel to Saturn and achieve orbit around this magnificent ringed planet. This is one of the most distant targets in the solar system, requiring exceptional mission planning.

30 min Single maneuver
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The Scenic Route

Perform a bi-elliptic transfer to raise your orbit. Sometimes going the long way around uses less fuel than a direct Hohmann transfer. Master this advanced orbital maneuver technique.

15 min Optimization
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Galilean Grand Tour

Visit multiple moons of Jupiter in a single mission. Use gravity assists from Io, Europa, and Ganymede to efficiently tour the Galilean satellites.

35 min Free form
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Race Against Time

A comet is passing through the inner solar system, and you have a narrow window to intercept it for scientific study. Speed is essential, but so is fuel efficiency.

18 min Free form
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Double Slingshot

Use both Venus and Earth in a gravity assist sequence to reach Jupiter with minimal fuel. This is the classic VEEGA (Venus-Earth-Earth Gravity Assist) maneuver.

30 min Free form
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Perfect Timing

You need to rendezvous with a target spacecraft, but you're in the wrong position in your orbit. Use phasing orbits to adjust your position and arrive at exactly the right time.

12 min Free form
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Plane Change Maneuvers

Master one of the most expensive maneuvers in spaceflight - changing your orbital plane. Learn techniques to minimize the massive fuel costs.

20 min Lesson
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Phasing Orbits

Learn to synchronize your position with a target spacecraft. Master the technique of using a different orbital period to catch up or slow down relative to another object.

20 min Lesson
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Expert 12 missions

Planetary Defense

Intercept a potentially hazardous asteroid and use a kinetic impactor to slightly alter its trajectory. Small changes now prevent Earth impact decades later. The fate of humanity depends on precision.

30 min Free form
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Solar Gravity Slingshot

Achieve the highest possible spacecraft velocity using a Jupiter gravity assist followed by a close solar perihelion burn (solar Oberth maneuver). Dive to within 4 solar radii, perform a powerful burn at maximum velocity, and escape the solar system at over 60 km/s - fast enough to reach 100 AU in 25 years.

45 min Free form
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Halley's Challenge

Attempt one of the most difficult rendezvous missions possible: matching velocity with Halley's Comet in its retrograde orbit. With a 162° inclination, this requires nearly reversing your orbital direction - an astronomical 16+ km/s plane change. Only attempted once (by Giotto in 1986 flyby), never achieved.

55 min Free form
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Beyond the Kuiper Belt

Explore the scattered disk, the most distant populated region of the solar system. Perform a Grand Tour of multiple trans-Neptunian objects beyond 40 AU, including at least one encounter beyond 50 AU. This multi-year expedition maps the outer frontier of our planetary system.

55 min Multi maneuver
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Dancing in Three Bodies

Enter a halo orbit around the Earth-Moon L2 Lagrange point. This three-dimensional orbit is challenging to establish but provides continuous line-of-sight to the lunar far side.

30 min Free form
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Belt Conqueror

Undertake an epic 8-10 year journey to visit all four of the largest asteroids: Ceres, Vesta, Pallas, and Hygiea. This Grand Tour of the asteroid belt requires masterful trajectory planning, as Pallas' 34° inclination makes it particularly challenging to reach. Use asteroid gravity assists where possible to conserve fuel.

50 min Multi maneuver
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Voyager's Legacy

Follow in the footsteps of the Voyager missions by visiting Jupiter, Saturn, Uranus, and Neptune using gravity assists. This is the ultimate test of mission planning and execution.

45 min Multi maneuver
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Journey to the Edge

Venture into the Kuiper Belt to encounter Makemake, one of the five dwarf planets and a pristine remnant from the solar system's formation. At 45 AU from the Sun, this 12-15 year odyssey pushes the boundaries of human exploration. Multiple gravity assists are essential for this extreme mission.

45 min Free form
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Jupiter's Big Four Marathon

Tour all four Galilean moons while surviving Jupiter's brutal radiation belts. Visit volcanic Io, icy Europa with its subsurface ocean, massive Ganymede with its magnetic field, and ancient Callisto. Balance science objectives against cumulative radiation dose in this challenging multi-moon mission.

50 min Free form
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Interstellar Speed Run

Break the speed record to the edge of the solar system. Voyager 1 took 35 years to reach 100 AU - you must do it in under 10 years. This requires an aggressive multi-planet gravity assist sequence culminating in a close solar flyby. Push spacecraft velocity to the absolute limit.

40 min Multi maneuver
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Titan Aerobrake Master

Use Titan's thick nitrogen atmosphere to gradually lower your orbit through repeated aerobraking passes. Each atmospheric pass removes orbital energy without using fuel, but fly too deep and you'll burn up. Achieve a stable science orbit around Saturn's largest moon using this advanced technique.

45 min Optimization
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Interplanetary Superhighway

Use a low-energy transfer along the weak stability boundary to reach the Moon with minimal fuel. This advanced technique exploits three-body dynamics for extreme fuel efficiency.

35 min Free form
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