Sea Launch User's Guide

Cooling air
From encapsulation to launch, conditioned air is provided to the payload
fairing volume. The cooling air flows from an entry on the side of the
payload fairing to the aft end, where it exits through one-way valves on
the payload structure. Conditioned air capabilities are described in detail
in section 5.
Thermal insulation
External thermal insulation protects the payload fairing structure and
limits the interior payload fairing surface temperatures. Payload fairing
jettison is constrained to a time sufficient to ensure that the maximum
dispersed free molecular heating (FMH) never exceeds spacecraft requirements.
The customer can tailor the time of payload fairing jettison
(and associated maximum FMH). The thermal environments are described
in section 5.
Interface skirt (IS)
The IS joins the payload fairing to the Block DM-SL and also supports
the spacecraft loads through the spacecraft adapter and payload structure.
The IS is constructed of aluminum with integral stiffeners (see fig. 2-9).
The IS is 0.81 m (2.6 ft) long and accommodates the transition from a
3.715 m (12.2 ft) diameter on the Block DM-SL to a 4.15 m (13.6 ft) diameter
on the payload fairing.
265807J3-067R2
Figure 2-9. Payload Unit Interface Skirt
REV B D688-10009-1 2-15