MISSION PLAN - PDS Small Bodies Node

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A serendipitous phasing of Earth and Wild-2 for the 2003 apparition presents additional opportunities to perform the mission at later dates with the resulting mission characteristics similar to the baseline launch period mission. The two launch opportunities correspond to 2 + year and 2 - year Earth Gravity Assist trajectory types but with comet encounter occurring pre-perihelion. The current spacecraft configuration (fixed solar arrays and HGA) can be preserved exactly, for encounter, if the encounter date is set at TP-103d. The spacecraft +z-axis (HGA) can remain pointed at Earth at comet closest approach with an off-sun angle close to 13° versus 17° in the baseline mission. Likewise, the heliocentric range is 1.88 AU compared to 1.86 AU and the Earth range is 2.74 AU compared to 2.61 AU. Although the alternate mission performance is yet to be thoroughly analyzed, it appears that the mass margin is comparable to that of the baseline mission. These alternate flights would require slightly higher C3’s, but this is compensated for by lower post launch ∆V. Tables 2.3-3 and 2.3-4 show the specific mission parameters for these alternate launch periods. 2.3.3 Space Environment This section contains space radiation and micrometeoroid data generated by JPL for the STARDUST project. The format of the data is a fairly standard and widely used by system designers. 2.3.3.1 Ionizing Radiation Fluence and Dose Fluence: Three sources of natural space charged particles are considered: galactic cosmic rays, solar winds and solar proton events. The resulting 7-year cumulative proton and electron integral fluences are shown in Table 2.3-5. The fluence values shown correspond to a 99% probability level. The rationale for choosing a 99% confidence level is that the spacecraft may experience a 95% probabilistic size flare every 2.8 years and a 98.7% probabilistic size flare every 7 years according to the JPL solar flare model. Therefore, it is deemed prudent to adopt the 99% probabilistic confidence level for a 7 year STARDUST mission. Radiation Dose: The ionizing dose to which the spacecraft is expected to be exposed as a function of aluminum thickness is shown in Figure 2.3-3. The calculation is made using Monte Carlo radiation transport code NOVICE and assumes a spherical shell geometry. These dose-depth data are generated based on the sum of the proton and electron fluence data listed in Table 2.3-5. This does not include the radiation design margin (RDM) required to account for other uncertainties associated with the mass distribution, electronic parts responses and transport calculations. A RDM of 2 is assumed somewhat arbitrarily based for the most part on past JPL managed missions. 28
Accumulation of Radiation with Time: Radiation fluence as a function of time is generated to accommodate concerns regarding solar array design. Figure 2.3-4 shows the accumulated levels of proton and electron fluences at L+380, 1180, 1820, 2090 and 2535 days. These data points correspond roughly to each of three aphelions, Wild-2 encounter and end of mission. To expedite practical applications, the complex degradation profile of solar cell performance due to the above radiation (multiple sources, wide range of energies and omni-directional) is converted and measured in terms of the equivalent damage caused by the incidence of a single 1-MeV electron on silicon cells. The equivalent damage conversion factors are different for different performance parameters: open circuit voltage (VOC or Pmax) and for short circuit current (ISC). Figure 2.3-5 shows the resulting equivalent 1-MeV electron fluence behind a coverglass of variable thickness and are given for solar cell performance parameters VOC and ISC, respectively. 29
Page 1 and 2: STARDUST MISSION PLAN February 1, 1
Page 4 and 5: STARDUST MISSION PLAN Edward A. Hir
Page 7 and 8: Table of Contents Table of Contents
Page 9 and 10: 10.1.1 Spacecraft Attitude History
Page 11 and 12: Figure 6.2-1.a Wild-2 Encounter Com
Page 13 and 14: Table 10.1-3 Spacecraft Attitude Pr
Page 15 and 16: kg km L L/O Kilogram Kilometer Laun
Page 17 and 18: Change Log Change Letter Date Affec
Page 19 and 20: 1.0 Introduction 1.1 Purpose The pu
Page 21 and 22: 2.0 Mission Overview 2.1 Mission Ob
Page 23 and 24: Fairing STARDUST Second Stage Star3
Page 25 and 26: propulsive maneuvers. To avoid pote
Page 27 and 28: The STARDUST camera is necessary to
Page 29 and 30: of-view is smaller, as described in
Page 31 and 32: Backshell Avionics Deck Parachute C
Page 33 and 34: Earth Gravity Assist 01/15/01 Earth
Page 35 and 36: Cruise 2 (Earth-Wild-2) ISP Collect
Page 37 and 38: 2.3.2 Launch Period Strategy 2.3.2.
Page 39 and 40: Table 2.3-2 Baseline Mission Parame
Page 41 and 42: Table 2.3-2 Baseline Mission Parame
Page 43 and 44: *B plane angle (deg) -41.051 -40.96
Page 45: 2.3.2.2 ∆V Budget The total ∆V
Page 49: Table 2.3-4 STARDUST Alternate-2 Mi
Page 52 and 53: calculations will require more deta
Page 54 and 55: 10 17 10 16 10 15 10 14 10 13 Fluen
Page 56 and 57: 8 10 flare, no shielding 6 10 4 10
Page 58 and 59: The orbit of comet Wild-2 was drast
Page 60 and 61: • Dust density = Nucleus density
Page 62 and 63: 2.4.4 Interstellar Dust Science Pla
Page 64 and 65: Launch Initial Acquisition TCM-1 Ac
Page 66 and 67: Stage II ignition t=277.5 s h=66.4
Page 68 and 69: Special ‘coming-off-theperiscope
Page 70 and 71: phases are very similar to the stan
Page 72 and 73: presented in tables contained in Ap
Page 74 and 75: Figure 4.2-4.b. Beta Meteoriod Impa
Page 76 and 77: 180 Off-SEP & ORBIT normal angle (d
Page 78 and 79: 2/6 launch Events Attitude 74 days
Page 80 and 81: yaw, while continuing to meet solar
Page 82 and 83: Time Image Description images pixel
Page 84 and 85: (EGA-60d to +30d) TCM 4 (EGA-60 d)
Page 86 and 87: 6.0 Wild-2 Encounter Phase (E-100 t
Page 88 and 89: the installation of the HGA. The su
Page 90 and 91: Date Sept-03 Oct-03 Nov-03 Dec-03 J
Page 92 and 93: Coma images will be acquired primar
Page 94 and 95: mirror via a simple one dimension t
Page 96 and 97:
The cross track error corresponds t
Page 98 and 99:
14 12 10 24 km 3 sigma distance 1 s
Page 100 and 101:
All 34-m HEF except selective 70-m
Page 102 and 103:
SRC Entry / Descent Atmospheric Ent
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Two TCM’s are planned within this
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It is important to note that, other
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8.0 Planetary Protection The object
Page 110 and 111:
Earth-Probe Range Sun-Earth-Probe A
Page 112 and 113:
9.1 Mission Data Set (cont) 14.00 E
Page 114 and 115:
14.00 MOON-PROBE RANGE Launch Phase
Page 116 and 117:
180.00 SUN-EARTH-PROBE ANGLE EGA Ph
Page 118 and 119:
180.00 SUN-PROBE-MOON ANGLE EGA Pha
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180.00 SUN- WILD-2 -PROBE ANGLE Enc
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Cone & Clock Angles of Wild-2 Cone
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180 Cone & Clock Angles of Sun 180
Page 126 and 127:
9.4 Wild-2 Encounter Data Set (cont
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16.00 MOON-PROBE RANGE Return Phase
Page 130 and 131:
10.0 Appendix B: Unbalanced Attitud
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spacecraft attitude when the spacec
Page 134 and 135:
Time From Launch Off-sun Angle (deg
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Acceleration (1E-11 km/s/s) 12 10 8
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+z, yaw +y, pitch +x, roll Figure 1
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** vectors evaluated at the time of
Page 142 and 143:
Rgt Ascen (deg) [eme'2000] 360 300
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Table 10.2-6 Communications Schedul
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Table 10.2-6 Communications Schedul
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031228 19180 0 031229 19180 0 03123
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TRAJECTORY CORRECTION MANEUVERS EVE
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2453509.10737773 50518. 143437. 229
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50204. 3437. 2189.12 outb SEP = 3 d
Page 156 and 157:
Table 12-1 ISP #1 Collection Period
Page 158 and 159:
Table 12-2 ISP #2 Collection Period
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Table 12-4 ISP #2 Spacecraft Attitu
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Table 12-5 CIDA #1 Collection Perio
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Table 12-6 CIDA #2 Collection Perio
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908.000 41.659 20.000 9.272 175.100
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Table 12-8 CIDA #1 Spacecraft Attit
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Table 12-9 CIDA #2 Spacecraft Attit
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Table 12-11 CIDA #3 Solar Conjuncti
Page 174 and 175:
13.0 Appendix E: PRD Traceability M
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