In [1]:
# Parameters
mk_ops_id = "juice_ops_v451_20240812_002"
mk_plan_id = "juice_plan_v451_20240812_001"
report_days = 15
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JUICE Cruise Report for juice_ops_v451_20240812_002¶

Abstract¶

The JUICE cruise trajectory report provides an overview of geometrical quantities and parameters of interest for a quick assessment of the current status of the JUICE cruise from the perspective of the JUICE Science Operations Center and to support the cruise activities of the instrument teams. The report is based on a given version of the Operational (ops) and Planning (plan) SPICE meta-kernels. Previous versions of the reports can be accessed from this link: https://juicesoc.esac.esa.int/cruise_reports/

Cruise Geometry Plots for 2024-07-28T11:52:10 - 2024-08-19T12:00:00¶

The following geometry plots are provided for the observed period:

  • S/C Attitude Angular Deviation in between the Planned and Measured attitude (Rotation around the resuling axis of the S/C rotation)1
  • S/C +Y axis Right Ascension and Declination in ECLIPJ2000 from the Measured attitude (contextualizes the S/C flips)
  • S/C to Sun angle with respect to the S/C +X Panel (including illumination warnings)
  • S/C to Sun angle with respect to the S/C +Z Panel (including illumination warnings)
  • Angle between HGA boresight and S/C to Sun direction
  • Angle between HGA boresight and S/C to Earth direction
  • Angle between Solar Arrays Normal and S/C to Sun direction from the S/C HK telemetry
  • MGA Azimuth and Elevation from the S/C HK telemetry
  • Angle between MGA boresight and S/C to Earth direction from the S/C HK telemetry

These plots might include either or both the Planned Attitude (as provided by Flight Dynamics in the ATTC Cruise Attitude Ephemeris Messages) and the Measured Attitude (the as-flown or executed attitude extracted from the Housekeeping telemetry of the S/C). The S/C Attitude Angular Deviation is provided as a single angular "error" that is calculated by obtaining the S/C rotation matrix for both the measured and planned attitude and obtaining the difference in between the angular rotaiton around the resulting rotation axis. More information of the Angular Rotation can be obtained from the header of the SPICE function in use.

The geometry plots include the following Flight Dynamics events in the background as orange intervals:

  • FLP Time periods when a flip to pass attitude happens
  • FLO Time periods when a flip to out-of-pass attitude happens
  • IXP Time periods when the sun illuminates the SC on the +X face
  • HGA Coverage period of the high gain antenna (HGA)
  • MGA Intended coverage period of the medium gain antenna (MGA)
  • WOL Period of a wheel off-loading (WOL) slot.
  • OMA Period of an orbit control manoeuvre (OCM) slot using the chemical propulsion system.
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The coverage of these plots is determined by the end time of the latest Measured (as-flown) attitude CK Kernel from the S/C Housekeeping telemetry (2024-08-12T11:51:40) or by the Predicted (ATTC) attitude CK Kernel from Flight Dynamics (2024-08-19T12:00:00) and its start time is set to 15 days before (2024-07-28T11:52:10).

Out[15]:

The resolution of the plots is set to 90s.

WARNING The S/C +Z Panel is illuminated in the measured attitude:

2024-07-29T06:34:06 - 2024-07-29T06:34:29

2024-07-31T04:41:48 - 2024-07-31T04:42:34

2024-08-01T03:46:02 - 2024-08-01T03:46:22

2024-08-02T02:48:50 - 2024-08-02T02:49:35

2024-08-03T01:52:48 - 2024-08-03T01:53:34

2024-08-04T00:56:52 - 2024-08-04T00:57:27

2024-08-05T00:44:26 - 2024-08-05T00:46:01

2024-08-09T00:19:59 - 2024-08-09T00:20:27

Cruise Flybys¶

The following section includes information for all the Cruise flybys. The flybys are summarized hereunder:

Out[29]:
LIST NAMES TIME UTC ALTITUDE [km] SSC LON [deg] SSC LAT [deg] SSC PHASE [deg] SSC LOCTIME [hours]
MOON_FB 2024-08-19T21:14:48 753.69 106.43 -12.40 110.22 19.37
EARTH_FB 2024-08-20T21:56:04 6802.57 163.14 24.03 47.62 8.75
VENUS_FB 2025-08-31T05:38:55 5090.03 357.10 -0.64 54.56 8.36
EARTH_FB 2026-09-28T11:40:31 8639.38 83.90 -22.08 81.12 17.42
EARTH_FB 2029-01-17T18:44:49 4644.84 21.16 16.22 122.95 19.98

In order to understand the applicable attitude for the flybys (SPICE CK) see the section SPICE Kernels Coverage of this report.

For periods were the attitude is not provided by predicted (juice_sc_attc*) or measured (juice_sc_meas*) CK kernels, the attitude implemented is the S/C SOC default attitude (juice_sc_crema_*_baseline*).

Please remember that this is the SOC prediction that does not correspond to the operational prediction that will be provided by Flight Dynamics and distributed as a SPICE Kernel by the SOC when the time comes.

The baseline attitude for flybys is defined by:

  • -Xsc is pointed at the sun
  • Zsc in the plane or the orbit around the target Zsc = -Xsc ^ (ScTargetPos ^ScTargetVel)

This attitude is applied from -3 hours before Closest approach (CA) to +3 hours CA. For LEGA, as an exception, the timeline for that period is as follows:

  • 2024-08-17T21:57:12 Moon FB Attitude Start (Earth CA -3 days)
  • 2024-08-19T21:15:55 Moon CA
  • 2024-08-20T09:57:12 Earth FB Attitude Start (Earth CA -12 hours)
  • 2024-08-20T21:57:12 Earth CA
  • 2024-08-23T21:57:12 Earth FB Attitude End (Earth CA +3 days)

The baseline flyby attitude does not include the S/C daily flips and simply keeps the beforementioned attitude.

Cruise Flybys geometry¶

For each flyby a map projection is provided with the following geometrical quantities:

  • Groundtrack with Altitude [km]
  • S/C +Z axis target intersection with Sun incidence angle [deg]

The incidence angle is measured between the outward normal (zenith direction) at the surface point and the direction from the surface point to the illuminator.

In addition, the following geometrical quantites are shown:

  • Altitude [km]
  • S/C +Z axis nadir offset [deg]
  • Phase Angle at groundtrack [deg]
  • Groundtrack velocity [km/s]

Please note that in case the +Z axis of the S/C does not intersect the target (due to the SOC default attitude) it will not be shown in the map projection.

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SPICE Kernels Coverage¶

The coverage of the SPICE kernels that correspond to the meta-kernel are provided hereunder. Note that the priority of the applicable attitude is ordered from bottom to top, meaning that the bottom CK is applied.

The coverage difference in between the current ORBC and ATTC files and the ones from the previous version of the meta-kernel are provided hereunder for convenience:

Out[39]:
FILE START TIME UTC STOP UTC TIME
juice_orbc_000069_230414_310721_v01.bsp 2023-04-14T12:42:17.657 2031-07-21T06:31:06.289
juice_orbc_000068_230414_310721_v01.bsp 2023-04-14T12:42:17.657 2031-07-21T06:31:40.039
juice_sc_attc_000069_230414_240819_v01.bc 2023-04-14T12:42:18.000 2024-08-19T12:00:00.000
juice_sc_attc_000068_230414_240819_v01.bc 2023-04-14T12:42:18.000 2024-08-19T12:00:00.000

The differences of the flybys in between the current and previous ORBC files are provided hereunder for convenience:

Out[40]:
FLYBY CURRENT ORBC TIME UTC PREVIOUS ORBC TIME UTC TIME DELTA [sec]
MOON_FB 2024-08-19T21:14:48 2024-08-19T21:14:55 -7.0
EARTH_FB 2024-08-20T21:56:04 2024-08-20T21:56:14 -10.0
VENUS_FB 2025-08-31T05:38:55 2025-08-31T05:30:05 530.0
EARTH_FB 2026-09-28T11:40:31 2026-09-28T11:38:39 112.0
EARTH_FB 2029-01-17T18:44:49 2029-01-17T18:47:50 -181.0
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