MISSION PLAN - PDS Small Bodies Node

Launch
Initial Acquisition
TCM-1
Activation and Checkout
0 - 30
0 - 1
15
1 - 30
30
1
-
29
3.2 Initial Acquisition Subphase
The initial acquisition subphase includes all activities from launch vehicle liftoff to
completion of Deep Space Network (DSN) acquisition. Although one complete day is
allocated for this activity, selection of the short coast launch option allows these activities
to be completed within three hours of launch.
Prior to liftoff (L/O), the spacecraft is powered on via launch vehicle umbilical power at
L/O-240 minutes. The spacecraft is transferred to internal battery power at L/O-4
minutes. At this time the spacecraft is electrically configured for initial cruise mode with
the exception that solar panels are not deployed and the solid-state power amplifier
(SSPA) is off.
The activities from liftoff to spacecraft separation are summarized in Table 3.2-1 and
illustrated in Figure 3.2-1. It should be noted that the numbers presented are specific to a
February 6 launch date, but are typical of other launch dates. However, the specific
numbers are provided for illustrative purposes only and are subject to change as mission
plans mature.
Table 3.2-1 Injection Activities
Event L/O+(sec) (min) Comments
PRE-LAUNCH
1 Spacecraft power ON -86400.0 -1440.0 Latch Valves Closed & System
Wet; EPS, C&DH, Rcvr, & DST
powered
2 Switch to internal power –240.0 -4.0 On batteries
3 Liftoff 0.0 0.0
PRE-SEPARATION
4 Power on Prop Heaters 241.0 4.0 1 lb thrusters, valve, line, tank
5 Main engine cutoff (MECO) 264.0 4.4
6 Stage II ignition 277.7 4.6
7 9.5 ft fairing separation 284.0 4.8
8 First Stage II cutoff (SECO 1) 597.3 10.0
9 Enter Solar Eclipse 902.0 15.0 02/06/99 launch
10 Restart Stage II 1309.8 21.8
11 SECO 2 1414.0 23.6
12 Stage II separation 1467.0 24.5
13 Power on IMU 1485.0 24.8 sep - 2 min, earliest across LP
14 Stage III ignition 1504.0 25.1
15 Stage III burnout 1569.3 26.2
16 Spacecraft separation 1639.0 27.3 Assumes 69.7 seconds coast
17 Open Latch Valves 1640.0 27.3 sep + 1 sec
18 Deploy LV Stage III Yo 1642.0 27.4
DESPIN
46