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LTP05 has been confirmed to run from 2021-09-27T00:00:00Z until 2021-12-27T00:00:00.000Z.

In March 2021, it was decided to change the typical duration of an LTP from 6 to 3 months, in order to allow Flight Dynamics to produce stable LTP input and to add flexibility by planning LTP closer to the execution dates.
This page has been constructed from the original page LTP04 July 2021-Sep 2021, started at MLP (Oct 2020), by copying over all information regarding the period Oct-Dec 2021.

Orbital context

Plots are in GSE (geocentric solar ecliptic) coordinates, so Earth is at [0,0], the Sun is at [1,0]. The plot is the projection of the orbit on the ecliptic plane.

Animated Version: Orbit_GSE_2021H2.mp4

New definition for the grey shading representing downlink rates:

  • white = maximum downlink rate at which you can empty the SSMM in ~10 days
  • light-grey = SSMM fill state decreases with everyone operating at EID-A rates
  • mid-grey = SSMM fill state increases within RSW (10 instruments operating) and decreases outside RSW (IS-only breakeven rate < downlink rate < inside-RSW breakeven rate )
  • dark-grey = SSMM fill state increases with just IS operating (downlink rate < IS-only breakeven rate)

RS checkout window placement

No RS checkout windows in LTP5.

Note that the first month of NMP is covered by this LTP: NMP starts officially at the Earth GAM on 2021-11-27. Nominal IS and RS science will start after the navigation window (~4 Dec 2021).

GAMs and conjunctions

  • Earth GAM 1 on 2021-11-27, GAM restriction period expected to run from 2021-10-30 to 2021-12-04

Science and calibration planning

Note the text in red highlights adjustments still to be made in SOOP Kitchen plan during Long Term Planning

IS calibrations:

  • MAG calibration roll to be scheduled in window 2021-10-01T00:00:00.000Z - 2021-10-04T00:00:00.000Z (heliocentric distance ~0.64 AU) (star) (time period to be confirmed as it is close to BC Mercury Flyby)
  • RPW calibration rolls (roughly daily) to be scheduled in window 2021-11-28 to 2021-12-04 when SC-Earth distance is within the range (115, 1000) Earth radii, and when Solar Orbiter is between -80 and +120 deg from the minus X GSE axis as defined in RPW EIDB (star)

RS calibrations: 

Context: TN on star calibration opportunities and planetary transits 

  • Some opportunities involving planetary transits or comets passing through FOVs:
    • Mercury moving through FSI FOV (2.63 Rsun) on 4 Oct, i.e. during the RS coordinated synoptics mentioned below. FSI may want to adjust the observations to take advantage of this opportunity. Off-pointing is not required (see comment at bottom page).
    • Venus opportunity on 24 Dec 2021, for Metis. No offpointing required.
    • Comet passing through Metis FOV on 15 Dec 2021
  • Metis star calibration opportunities (note: data volumes in SOOP Kitchen are placeholders):
    • 2021-12-17 - 2021-12-26, θ Ophiuchi
  • Both EUI and PHI plan to run a test annealing campaign at the end of Cruise phase, i.e. after RSCW4 (decision made by RSWG at SOWG#14). Still to be planned in SOOP Kitchen.
    • EUI input: This annealing campaign is meant to assess the detector degradation and in case of strong degradation, to foresee an annealing campaign preceded and followed by an onboard calibration to assess its efficiency. Ideally, this campaign would have a TM of 1900 MiB. If this is not feasible, we can limit the TM by taking subframes.

IS-only science:

  • IS science modes, incl. regular and coordinated bursts
  • High rate observations for the in situ instruments for the following period:
    • 2021-12-04 - 2022-01-01 (start nominal mission phase, plentiful downlink)

Coordinated science (and cross-calibration) campaigns:

These address the opportunities identified during SWT 27 (listed in the table below)

  • Remote sensing synoptic programme (based on L_FULL_LRES_MCAD_Coronal-Synoptic SOOP definition with additional SPICE observations included - to be reviewed) during the following periods:
    • 2021-09-20 (=LTP4) - 2021-10-11  (post RSCW, support BC Mercury Flyby; 180 degree field ambiguity resolution)
    • 2021-12-04 - 2022-01-01 (start nominal mission phase, assumed default synoptic programme)
  • Cross- and inter-calibration opportunity with Earth-based assets, aligned with crossing the Earth-Sun line on 5 Nov 2021 (note this is during the NAV window, detailed timing TBC by flight dynamics). Data volumes currently placeholders (PHI, SPICE, Metis, EUI, SoloHI)
  • RS Instruments with internal memories can transfer extra TM to the SSMM after the RSCW4, to take advantage of good downlink performance close to Earth. In SOOP Kitchen, this is visible as follows:
    • EUI delaying the last transfer of TM to after the checkout window. Note that EUI still needs regular flushes during the checkout because of limited space in internal memory.
    • PHI processing most of the data from the checkout after the window. PHI will not only transfer processed but also some raw data (represented by the raw data generation observation on 19 Sep)
    • STIX flushes of internal buffer, several days after the end of the window, when extra data downlink is available.


(star) Note that the coordinated off-pointing campaigns and rolls need to be requested to MOC (flight dynamics) before LTP planning and timing/details cannot be changed anymore at time of Long Term Planning.

Context from mission level planning during SWT27 (Oct 2020)

Since launch, comms performance has been found to be much better than baselined, so there is significant scope for extra activities. These were handled directly by the SOWG for LTP2 and LTP3, however for LTP4 the priorities for how to use the additional telemetry will be set by the SWT in line with the expected procedure for the nominal mission phase. The new level of available telemetry is summarised in the below plot. The decision taken by the SWT in order to use this Telemetry are reflected in the information above. This section is left here for context.

Note there will be some carry-over of data from LTP3 and 4, and the SSMM will need to be empty close to the EGAM to allow for repartitioning.

First priority will be given to completing any necessary calibration and characterisation campaigns, followed by addressing the science priorities decided by the SWT.

Context for PSP coordination:


Orbit plots courtesy of V. Andretta.

SOOP Kitchen plan

High-level (=MLP) plan of whole cruise:

Starting point for LTP05 planning in SOWG#18: to be added after SAP has been frozen in SWT#29 (May 2021) and LTP5 event files have been received from MOC (start July 2021)

Final plan LTP05: to be added after SOWG#18 (July 2021)


Reference material


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2 Comments

  1. Some data regarding the Mercury passage close to the Sun on 4 Oct (no transit but 'near miss'):

    • smallest angular separation between Mercury and Sun will be (from webgeocalc):
      2021-10-04 20:30:00.000000 UTC         1.07069009 degrees
    • EUI/FSI FOV is 3.8 degrees wide (half width 1.9 deg) so offpointing is not required as Mercury will be captured in the FOV
    • Solar Orbiter will be roughly at 0.65AU from the Sun: the angular size of the Sun will be 0.82 deg and Mercury's angular size will range from 20 to 37" roughly

    4 Oct falls during the synoptic observations that have been scheduled already during mission level planning (see https://solarorbiter.esac.esa.int/soopkitchen/#/planning/plan/Mission%20Level%20Plan%20for%20LTP4%20Only)

  2. Robin pointed out at SWT#28 that C/2021 A1 (Leonard), discovered this year, will be visible in SoloHI's FOV 17–21 December. No rolls required.