Sea Launch User's Guide

3.5 Spacecraft Separation
Separation event
Spacecraft separation typically occurs 500 sec after the final Block DM-
SL main engine shutdown. This allows for engine cooling and reorientation
to the required spacecraft separation attitude. Several hours after
separation, the Block DM-SL performs a contamination and collision
avoidance maneuver (CCAM), which prevents future contact with the
spacecraft. The Block DM-SL then vents all residual propellant and gasses
and depletes any remaining charge in its batteries.
Separation capabilities
The separation system provides a relative velocity between the Block
DM-SL and the spacecraft of at least 0.3 m/sec. The Block DM-SL attitude
control system can provide a longitudinal spin rate if desired. The
separation springs can provide a straight pushoff or a small transverse
angular rate.
Attitude and attitude rate accuracy depend heavily on spacecraft mass
properties and spin rate, but for preliminary purposes may be assumed to
be ±2.5 deg and ±0.6 deg/sec in all three axes for a nonspinning separation
(2.3σ).
Injection accuracy
The injection accuracy at spacecraft separation is a function of the injection
orbit and the mission flight duration. Table 3-3 indicates the injection
accuracy for a standard GTO mission (2.3σ).
Table 3-3. Standard GTO Injection Accuracy (2.3σ)
Orbital Parameter
Perigee height
Apogee height
Inclination
RAAN
Argument of perigee
Injection Accuracy
± 10 km
± 80 km
± 0.25 deg
± 0.25 deg (nonzero inclinations)
±0.25 deg (nonzero inclinations)
REV B D688-10009-1 3-15