🌍 Orbital Speed Calculator
Calculate Orbital Velocities for Planets, Moons, and Satellites
Understanding Orbital Mechanics
Every object in orbit—from the Moon around Earth to Earth around the Sun—travels at a precise speed determined by gravitational forces. Our Orbital Speed Calculator computes these velocities using Kepler’s laws and Newton’s gravitational equations. Earth orbits the Sun at 30 km/s (67,000 mph)—fast enough to circle the planet in 3 minutes! The International Space Station races around Earth at 7.66 km/s, completing an orbit every 90 minutes. Understanding orbital speeds is crucial for mission planning, satellite deployment, and comprehending why planets closer to the Sun move faster than distant ones.
This calculator from SpaceTimeMesh uses the formula v = √(GM/r) where G is gravitational constant, M is central body mass, and r is orbital radius. It reveals fascinating patterns: Mercury speeds around the Sun at 47 km/s while distant Neptune crawls at 5.4 km/s. This isn’t arbitrary—it’s the inevitable result of balancing gravitational pull against centrifugal force. Objects in low Earth orbit travel faster than those in geostationary orbit. The tool helps space agencies calculate delta-v requirements for orbital transfers and understand why achieving orbit requires such tremendous energy.
Perfect for aerospace students studying orbital mechanics, mission planners calculating spacecraft trajectories, educators demonstrating Kepler’s laws, or space enthusiasts understanding why satellites at different altitudes have different speeds. Discover why geostationary satellites must orbit at exactly 35,786 km altitude, why the Moon is slowly drifting away from Earth, and how orbital velocity determines whether an object stays in orbit, escapes, or crashes.
Calculate Orbital Velocities
Orbital Speed Calculator
Discover how fast you're moving through space right now
Your Location
Enter your location for accurate rotation speed
Speed Breakdown
Individual components of your cosmic journey
Distance Calculator
How far you've traveled while reading this page
Put Your Speed in Perspective
How your cosmic speed compares to everyday speeds
Visualizing Your Cosmic Motion
Understanding Cosmic Motion
Earth's Rotation
Earth spins once every 24 hours. At the equator, you're moving at 1,674 km/h (465 m/s). At the poles, you're barely moving at all!
Orbiting the Sun
Earth travels around the Sun at 107,000 km/h (29.78 km/s). We complete one orbit every 365.25 days - that's one year!
Galactic Motion
Our entire solar system orbits the Milky Way's center at 792,000 km/h (220 km/s). One galactic year takes 230 million Earth years!
Local Group
The Milky Way is moving toward Andromeda galaxy at 100 km/s. They'll collide in about 4.5 billion years!
Through the Universe
Our Local Group is racing toward the "Great Attractor" at 627 km/s - about 2.3 million km/h through space!
Why Don't We Feel It?
All motion is relative! We don't feel these speeds because everything around us is moving together. No acceleration = no sensation.
Mind-Blowing Speed Facts
🚀 Extreme Speed Comparisons
Where Could You Go?
At your current speed, how long to reach...
How to Use the Orbital Speed Calculator
Step 1: Select Orbital System
Choose the central body (Sun, Earth, Jupiter, etc.) and the orbiting object. Options include all planets around the Sun, moons around their planets, or artificial satellites at various altitudes around Earth. Each combination has unique orbital characteristics.
Step 2: Input Orbital Parameters
Enter the orbital radius or altitude. For planets, use semi-major axis length. For satellites, specify altitude above surface. The calculator handles circular orbits directly and provides average velocity for elliptical orbits based on orbital energy.
Step 3: Analyze Results
View orbital speed in km/s, mph, and m/s. See orbital period (how long one complete orbit takes), compare to escape velocity, and understand the relationship between altitude and speed. Discover why lower orbits require higher speeds to maintain stability.
Orbital Speeds Across the Solar System
☿ Inner Planets (Fast)
Mercury: 47 km/s, Venus: 35 km/s, Earth: 30 km/s, Mars: 24 km/s. Inner planets race around the Sun due to strong gravitational pull. Mercury completes an orbit in just 88 Earth days! Explore orbital periods for all planets.
♃ Outer Planets (Slow)
Jupiter: 13 km/s, Saturn: 9.7 km/s, Uranus: 6.8 km/s, Neptune: 5.4 km/s. Distant planets move leisurely due to weak solar gravity. Neptune takes 165 Earth years per orbit—it hasn’t completed one full orbit since its 1846 discovery! See our age calculator.
🛰️ Earth Satellites
ISS (400 km): 7.66 km/s, GPS (20,200 km): 3.87 km/s, Geostationary (35,786 km): 3.07 km/s. Lower satellites move faster—counterintuitive but essential! The ISS must constantly boost its orbit due to atmospheric drag. Track the ISS position real-time.
🌙 Planetary Moons
Moon around Earth: 1.02 km/s, Io around Jupiter: 17.3 km/s, Titan around Saturn: 5.57 km/s. Moons closer to massive planets orbit faster. Io completes an orbit in 1.77 days! Calculate lunar orbital mechanics in detail.
The Physics of Orbital Velocity
Circular Orbit Formula
v = √(GM/r) where v is orbital velocity, G is gravitational constant (6.674×10⁻¹¹ N⋅m²/kg²), M is central body mass, r is orbital radius. This formula shows velocity decreases as √r—double the distance means √2 (≈0.707) times the speed. It’s derived from balancing gravitational force with centripetal acceleration.
Kepler’s Third Law
T² ∝ r³ where T is orbital period, r is semi-major axis. This means orbital period increases faster than distance—Saturn is 10× farther from the Sun than Earth but takes 30× longer to orbit. Combined with velocity formula, this creates the pattern where distant objects orbit more slowly both in speed and period.
Elliptical Orbits
Most orbits are elliptical, not circular. Objects move faster at perihelion (closest approach) and slower at aphelion (farthest point). Earth varies from 30.29 km/s (January) to 29.29 km/s (July). The vis-viva equation v² = GM(2/r – 1/a) describes velocity at any point in an elliptical orbit, where a is semi-major axis.
Frequently Asked Questions About Orbital Speeds
Why do closer objects orbit faster?
Because gravity is stronger closer to the central body. To maintain orbit, objects must achieve a balance between gravitational pull inward and centrifugal force outward. Closer objects experience stronger gravity requiring higher tangential velocity to avoid falling inward. This is why Mercury races at 47 km/s while Neptune crawls at 5.4 km/s. It’s counterintuitive because we expect closer = slower, but orbital mechanics inverts this expectation.
What happens if a satellite slows down?
It drops to a lower orbit where it must actually speed up! This seems paradoxical. When a satellite fires retro-rockets to slow down, it loses altitude. At the lower altitude, gravitational force is stronger, requiring a higher orbital velocity to maintain stable orbit. Conversely, speeding up raises the orbit where velocity decreases. This is why orbital rendezvous is complex—speeding up to “catch” a satellite ahead actually moves you to a higher, slower orbit, making you fall behind!
How do geostationary satellites stay over one spot?
They orbit at exactly 35,786 km altitude where orbital period matches Earth’s 24-hour rotation. At this altitude, orbital velocity is 3.07 km/s—precisely the speed needed to complete one orbit as Earth completes one rotation. The satellite stays above the same point on the equator. This only works at one specific altitude; move higher or lower and the orbital period changes, breaking synchronization. That’s why geostationary satellites cluster at this single orbital ring.
Can you orbit at any altitude?
Theoretically yes, but practical limits exist. Too low and atmospheric drag causes orbital decay—the ISS at 400 km requires periodic boosts. Too high and other factors dominate—radiation exposure increases, communication delays grow, and eventually you reach the Hill sphere boundary where other bodies’ gravity interferes. Most Earth satellites orbit between 200 km (minimum sustainable) and 35,786 km (geostationary), though some specialized missions go higher. Each altitude has tradeoffs between coverage, latency, and decay rate.
Explore More Orbital Mechanics Tools
Understand the physics of orbits and space travel:
- Orbital Period Calculator – Calculate how long orbits take
- Delta-V Calculator – Compute fuel requirements for orbital maneuvers
- Hohmann Transfer Calculator – Plan efficient orbital transfers
- Escape Velocity Calculator – Calculate speeds needed to leave orbit
- Gravity Assist Simulator – Understand planetary slingshots
- Satellite Coverage Calculator – Determine ground coverage from orbit