MISSION PLAN - PDS Small Bodies Node

2.3.2.2 ∆V Budget
The total ∆V budget is summarized in Table 2.3-2.a. It is based primarily on the
maximum total of deterministic maneuvers across the launch period, 260 m/s, and the
estimate of the required statistical trajectory correction maneuvers. Note that the
unallocated ∆V reserve amounts to 37 m/s. The statistical maneuver history for a Feb. 6
launch is shown in Table 2.3-2.b and leads to the allocation of 63 m/s indicated in Table
2.3-2.a.
Table 2.3-2.a ∆V Budget Summary
Deterministic (m/s) Notes
DSMs 260 Three or four DSMs depending on LD. Max of 20-day LP
(2/14).
Launch Window ± 1 min 2 For collision avoidance with space debris etc.
Slew ∆V effects 5 Cost of ACS Slew ∆V when modeled in Navigation software
Return divert 15 For S/C divert away from earth, executed at ~ 4 hrs before entry
Statistical
TCMs (19) 63 See Table 2.3-2.b for representative profile
ACS Modeling Error 10 Cost in ∆V due to the difference between models and actuals
Sub-Totals 355
Reserve 22 Additional 17 m/s available for full propellant load (85 kg)
Total 377 Initial design requirement
Table 2.3-2.b Maneuver History
Maneuver Epoch Execution Date ∆V-95% (m/s)
TCM-1 L + 15 d 21 Feb 99 44.93
TCM-2 DSM-1 10-14 Mar 00 169.80
TCM-3 DSM-1 + 30 d 13 Apr 00 2.86
TCM-4 EP - 60 d 16 Nov 00 0.44
TCM-5 EP - 10 d 05 Jan 01 0.32
TCM-6 EP + 30 d 14 Feb 01 2.74
TCM-7 DSM-2 13 Mar 02 0.75
TCM-8 DSM-3 04-06 Jul 03 69.87
TCM-9 DSM-3 + 7 d 13 Jul 03 1.48
TCM-10 WCA - 30 d 03 Dec 03 2.26
TCM-11 WCA - 10 d 23 Dec 03 1.46
TCM-12 WCA - 2 d 31 Dec 03 2.60
TCM-13 WCA - 18 h 02 Jan 04 2.02
TCM-14 WCA - 6 h 02 Jan 04 1.31
TCM-15 DSM4 (WCA + 30 d) 01 Feb 04 7.52
TCM-16 3rd aphelion 01 Oct 04 0.66
TCM-17 ER - 60 d 16 Nov 05 2.63
TCM-18 ER - 13 d 02 Jan 06 0.36
TCM-19 ER - 1 d 14 Jan 06 0.23
* Analysis completed 11/20/98, corresponds to 2/6 launch, DTO trajectories and PMA LV covariance.
2.3.2.3 Alternate Launch Periods
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