MET (Mission Elapsed Time):
T+00:00:00
View Mode:
Total Delta-V Budget
114.0 m/s
Margin: +42.6 m/s (Nominal)
Perigee (Post-Deorbit)
42.8 km
Entry Interface Achieved
Propellant Consumed
284 kg
NTO / Hydrazine MMH
Projected Disposal
Point Nemo
T+49h 22m (Oct 11)
Orbital Departure Physics & ISS Egress Criteria
1. Canadarm2 Release & Egress
Spacecraft such as Northrop Grumman's Cygnus and JAXA's HTV do not dock directly; they are berthed by the Space Station Remote Manipulator System (Canadarm2) to the Unity or Harmony nadir ports.
- Robotic unberth maneuvers take ~2.5 hours.
- Release occurs at the Nadir Release position (-RBAR).
- The vehicle drifts under natural orbital mechanics until outside the 200m Keep-Out Sphere.
2. Clohessy-Wiltshire Phasing
Relative motion between the departing cargo vessel and the Space Station is governed by the Hill-Clohessy-Wiltshire (CW) equations of relative orbital motion.
- A retrograde or nadir burn imparts a downward & forward relative drift.
- Lowering orbit increases orbital speed, causing Cygnus to accelerate ahead and below the ISS.
- Prevents re-contact even in the event of an attitude control malfunction.
3. Targeted Destructive Deorbit
Unlike reusable capsules (SpaceX Dragon), uncrewed freighters (Cygnus, Progress) perform a dual-purpose mission: delivering scientific gear and disposing of station garbage.
- Loaded with several metric tons of expendable research and waste.
- Targeted burn ensures breakup occurs over the South Pacific Ocean Uninhabited Area (SPOUA / Point Nemo).
- Internal payloads (like Saffire fire experiments) ignite prior to entry.