Aerospace & Aeronautical Engineering / Keplerian Orbit Mechanics
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LABORATORY 41 · AEROSPACE & AERONAUTICAL ENGINEERING

Keplerian Two-Body Orbit Determination and Vis-Viva Velocity

Determine spacecraft orbital velocity v(r) and specific mechanical energy epsilon from geocentric radius r using Kepler's laws and the Vis-Viva energy equation. Explore interactive wind tunnel simulation, flight dynamics, and aerospace engineering telemetry.

AERODYNAMICS · PROPULSION · FLIGHT DYNAMICS

Your virtual aerospace engineering laboratory.

ORBITAL VELOCITY SQUARED—
FLIGHT & TEST CELL TELEMETRY

Ready to sample with (1/r)x10^7 = 1.25 m^-1.

1.25 m^-1
Central body: Earth (mu = 3.9860 x 10^14 m^3/s^2)

Adjust (1/r)x10^7, then execute aerospace trial.

Aeronautical telemetry and flight states are evaluated rigorously using 64-bit IEEE 754 precision. Residuals reflect ordinary least-squares regression across successive observations. Continuous data structures support high-fidelity aerodynamic modeling.

Aeronautical assumptions and boundary condition limits

Pure Keplerian two-body formulation neglects non-spherical Earth gravity harmonics (J2, J3, J4). Linear regression of orbital velocity squared against inverse radius yields a slope 2*mu = 7.9720 x 10^14 m^3/s^2 corresponding to Earth mu = 3.9860 x 10^14 m^3/s^2 with R^2 > 0.999999.

Aeronautical apparatus & wind tunnel sensors.

Orbital Trajectory Numerical Propagator

Solves two-body equations of motion using 8th-order Dormand-Prince numerical integration.

Deep Space Network (DSN) Telemetry Simulator

Simulates 2-way coherent Doppler range-rate velocity measurements and range time delays.

Keplerian Orbital Element Converter

Transforms Cartesian state vectors (r, v) into classical orbital elements (a, e, i, Omega, omega, nu).

Geocentric Coordinate Reference Frame

Earth-Centered Inertial (ECI J2000) frame tracking satellite state vectors.

Orbital Energy & Angular Momentum Monitor

Verifies conservation of specific mechanical energy epsilon and angular momentum h.

Satellite Ground Track Visualizer

Plots 2D Mercator ground tracks with ascending node regression and orbit footprints.

FOLLOW THE METHOD

A reason behind every step.

Determine spacecraft orbital velocity v(r) and specific mechanical energy epsilon from geocentric radius r using Kepler's laws and the Vis-Viva energy equation. Standardized parameter settings: 1.05, 1.14, 1.22, 1.31, 1.4, 1.48 m^-1.

01

Orbit Definition and Initialization

Initialize an eccentric Earth orbit with perigee altitude h_p = 400 km and apogee altitude h_a = 10,842 km (semi-major axis a = 12,000 km, e = 0.435).

02

Gravitational Parameter Datum

Confirm Earth gravitational parameter mu = 3.986004 x 10^14 m^3/s^2 and Earth mean radius R_E = 6378.137 km.

03

Telemetry State Vector Sampling

Track the satellite through true anomaly positions corresponding to inverse radius (1/r) x 10^7 = 1.05, 1.14, 1.22, 1.31, 1.40, and 1.48 m^-1.

04

Orbital Velocity Acquisition

Record instantaneous inertial velocity magnitude v at each radial station using simulated Doppler telemetry.

05

Specific Energy Verification

Calculate specific orbital energy epsilon = 0.5 * v^2 - mu / r, confirming constancy across all observation points.

06

Vis-Viva Linear Regression

Plot (v^2) x 10^-7 versus (1/r) x 10^7, perform linear regression to determine slope 2*mu x 10^-14, and compute semi-major axis from the intercept.

YOUR NOTEBOOK · 0 OBSERVATIONS

Turn measurements into aerodynamic insight.

See a complete example report ↗

Points are your recorded observations. The solid regression line validates Keplerian Orbit Mechanics mathematical scaling.

LINEAR REGRESSION FIT · y = mx + b
v^2 = 2\mu \left(\frac{1}{r}\right) - \frac{\mu}{a} \implies \left(v^2 \times 10^{-7}\right) = m \cdot \left(\frac{1}{r} \times 10^7\right) + b
#Inverse Radius Parameter (m^-1)Orbital Velocity Squared (m^2/s^2 x 10^-7)Inverse Orbital Radius (1 / r) x 10^7 (m^-1)Orbital Velocity Squared (v^2) x 10^-7 (m^2/s^2)Remove

No readings yet. Execute an aerodynamic trial and record it.

Calculate it yourself.

CHECK YOUR UNDERSTANDING

Explain what the aerodynamic metrics mean.

What fundamental physical conservation law is expressed by the Vis-Viva equation v^2 = mu * (2/r - 1/a)?

What is the standard gravitational parameter mu_Earth for planet Earth?

Where does a spacecraft travel at its absolute maximum velocity in an eccentric elliptical orbit?

For a measured regression slope m = 7.9720 x 10^14 m^3/s^2, what is the extracted primary gravitational parameter mu = m / 2?