LEO Rendezvous & Proximity Operations Lab

Orbital Rendezvous Planner & Trajectory Lab

Simulate orbital phasing, transfer burns, relative motion, and terminal docking approaches for crewed spacecraft rendezvous with the International Space Station.

Orbital Trajectory & Approach View

Real-time Keplerian two-body propagation with Clohessy-Wiltshire proximity mapping
Phase Angle
42.50°
Relative Range
5,280km
Relative Velocity
14.2m/s
Catch-up Rate
2.36°/hr
Target (ISS, 418 km)
Chaser (Dragon)
Burn Point
Chaser Orbit: 205 × 310 km (Period: 89.6m)
Station Orbit: 418 × 418 km (Period: 92.9m)
Current Phase: Phasing Orbit (Co-elliptic)
Time to Next Burn: 02h 45m
Time Warp:
MET 00:00:00
T+0h T+24h
Trajectory calculated. Scrub timeline or play to watch phasing.

Maneuver Execution Schedule

Event / Burn MET Burn Δv Target Orbit Range

Orbital Mechanics Principles

How does a spacecraft "speed up" to catch a station ahead?

Counter-intuitively in orbital mechanics, speeding up directly expands your orbit, making your orbital period longer and causing you to fall further behind. To catch an orbiting space station ahead, the chaser drops into a lower orbit where its orbital velocity is faster and its period is shorter (Kepler's Third Law: $T^2 \propto a^3$). This orbital drift rate closes the phase angle.

What is co-elliptic phasing?

A co-elliptic orbit maintains a nearly constant altitude difference from the target station's orbit across all true anomalies. This keeps the line-of-sight elevation and relative geometry predictable for navigation sensors (star trackers and LIDAR) before initiating the final Transfer Initiation (TI) burn.

What are V-bar and R-bar approaches?

In proximity operations, navigation is defined along the local-vertical local-horizontal (LVLH) frame. V-bar is aligned with the station's orbital velocity vector (approaching from behind or in front), while R-bar is along the radial vector pointing directly toward Earth center (approaching from below).

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