MISSION PLAN - PDS Small Bodies Node

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2/6 launch Events Attitude 74 days DSM-1 (390-394) SEP < 4° +30d TCM 360 376 sunpoint: collector steering 364 388 452 50km/s particle 469 20° off-sun 472 2/15 launch 83 days* Events Attitude SEP < 4° 357 DSM-1 (387-391) +30d TCM 373 sunpoint: collector steering 372 396 459 50km/s particle 475 20° off-sun 478 * calendar days 82 “full grid” days 2/25 launch Events Attitude SEP < 4° 346 368 DSM-1 (398-402) 384 +30d TCM sunpoint: collector steering 371 53 days 438 50km/s particle 456 20° off-sun 459 Time days from 2/6 265 295 325 355 385 415 445 475 505 535 565 595 calendar date 10/29/99 11/28 12/28 1/27 2/26 3/27 4/26 5/26 6/25 7/25 8/24 9/23 CIDA Experiment Figure 4.2-8 ISP 1 Variability Across the Launch Period The CIDA 1 and 2 periods currently allow for some quiet time between the end of important mission phases, Launch and EGA, respectively, and the start of CIDA activity. Geometrically, these periods could start as early as L+20 days (vs. +45 days) and L+740 days (vs. +769 days), respectively. However, operationally, these periods are solidly restricted by the end of the Launch (L+30 days) and EGA (L+739 days) phases. The baseline CIDA 3 plan does not provide for off-sun attitudes during the pre-encounter solar conjunction period (SEP < 3° for 75 days). However, without a specific spacecraft attitude plan, this portion of the CIDA period will be very inefficient due to the attitude reference to the Sun-Earth-Probe plane (which will be slowly rotating 180° as the spacecraft passes through solar conjunction). A plan can be developed that includes sequenced attitude updates during solar conjunction for more efficient tracking of the ISP stream. The experiment characteristics and associated spacecraft attitudes for implementation of standard CIDA experiment strategies (+x-axis alignment with ISP stream, ISP stream within FOV) during this period are presented in Appendix D. Finally, the start of off-sun attitudes for CIDA 3 is dictated by the spacecraft exit from the pre-encounter solar conjunction. For planning purposes, ‘exit’ has been defined as a Sun-Earth-Probe angle of 3 degrees. If operational experience shows that communications are possible at smaller SEP angles, the CIDA 3 off-sun period could be initiated earlier than currently scheduled, L+1703 days. To provide some perspective, in the current trajectory, a Sun-Earth-Probe angle of 2 degrees is achieved at L+1693 days. 60
4.2.4 Mission Operations Considerations Current mission operations plan to issue a minimum of weekly updates to the spacecraft attitude and aerogel grid collector angle during ISP collection, and spacecraft attitude during the CIDA experiment. An intentional lead-lag strategy should be established for most efficient tracking of the ISP stream. However, the final spacecraft attitude and collector angle update schedules can be established only after the post launch final uplink schedule is known. JPL will provide a list of daily spacecraft attitudes and collector angles (see section 12) from which LMA will build the required lead-lag update schedule. 4.3 Mission Operations Mission operations during the Cruise phases are summarized in Tables 4.3-1.a-c. The operations during these phases drop to the lowest level of the mission. Activities required are essentially to maintain the spacecraft attitude profile to ensure adequate reception of solar power, communication with Earth at the scheduled times and tracking of ISP’s during the collection and CIDA periods. In addition, the spacecraft gathers and transmits information on spacecraft health as well as the sporadic science data. Imaging plans during cruise are limited to calibrations and standard camera maintenance. These plans are described in Table 4.3-2. Primary activities on the ground are spacecraft subsystem analysis and maintenance, and the generation of uplink commands. DSN tracking continues using the 34-m HEF network. Medium Gain Antenna (MGA) tracking is performed to obtain radiometric data for orbit determination and DSM/TCM formulation. This radiometric data is comprised of both ranging data and two-way Doppler data (See the Navigation Plan for more details). Spacecraft mode tracking is performed for telemetry and command. An uplink frequency of once per month is anticipated, however, commanding will increase during ISP collection and CIDA periods to allow tracking of the reference particle. The current request for DSN tracking in support of DSM-1 and its cleanup maneuver, TCM-3, is reduced from the baseline for TCMs. The power constraint to avoid casting shadows on the solar arrays with the whipple shields, and sun-Earth geometry during this phase of the mission would drive a need for large yaw slews (rotation about the z-axis), 160° over 4 hrs, between the ISP collection attitude and the MGA communications attitude. Given this slew scenario, the daily communication requirement surrounding TCMs reduces the amount of time available for ISP collection. Two action are taken to reduce the impact of NAV tracking on spacecraft slewing and on ISP collection time. The first is to schedule use of the HGA instead of the MGA. The HGA’s tighter deadband, together with small SPE angles (also coincident with this phase of the mission), allows the spacecraft to communicate with the Earth without performing a large 61
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STARDUST MISSION PLAN February 1, 1
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STARDUST MISSION PLAN Edward A. Hir
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Table of Contents Table of Contents
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10.1.1 Spacecraft Attitude History
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Figure 6.2-1.a Wild-2 Encounter Com
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Table 10.1-3 Spacecraft Attitude Pr
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kg km L L/O Kilogram Kilometer Laun
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Change Log Change Letter Date Affec
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1.0 Introduction 1.1 Purpose The pu
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2.0 Mission Overview 2.1 Mission Ob
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Fairing STARDUST Second Stage Star3
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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 and 46: 2.3.2.2 ∆V Budget The total ∆V
Page 47 and 48: Accumulation of Radiation with Time
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 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
Page 104 and 105: Two TCM’s are planned within this
Page 106 and 107: It is important to note that, other
Page 108 and 109: 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
Page 120 and 121: 180.00 SUN- WILD-2 -PROBE ANGLE Enc
Page 122 and 123: Cone & Clock Angles of Wild-2 Cone
Page 124 and 125: 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
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10.0 Appendix B: Unbalanced Attitud
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spacecraft attitude when the spacec
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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
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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
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Table 12-1 ISP #1 Collection Period
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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
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13.0 Appendix E: PRD Traceability M
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