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LTP04 has been confirmed to run from 2021-06-28T00:00:00Z until 2021-09-27T00:00:00Z.

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 was originally called "LTP04 July 2021-Dec 2021" and included the mission-level planning for the full 6 months period done at SWT#27 (Oct 2020).
We now greyed out all information regarding the period Oct-Dec 2021 and copied that to the new page LTP05 Oct 2021-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



EXT Start/
GAM restriction Start



Range [AU]

Range [deg]

Angle Range


Safe Mode Comms Blackout

Largest Comms Roll

GAM Restrictions

LTP 04RSCW4 (cold)n/a2021-09-12T00:00:002021-09-20T00:00:000.5870.5890.5950.751.131.47


38.61nono0 (TBC)no

GAMs and conjunctions

  • Venus GAM 2 on 2021-08-09, GAM restriction period expected to run from 2021-07-12 to 2021-08-16
  • Earth GAM 1 on 2021-11-27, GAM restriction period expected to run from 2021-10-30 to 2021-12-04 (now in LTP05)

Science and calibration planning

IS science + 4th opportunity for RS payload to characterise and calibrate the instruments.

  • IS science modes, incl. regular and coordinated bursts
  • 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) - now in LTP05
  • RSCW4: 8-day window of RS instrument specific characterisation and calibration campaigns (cold checkout)

Coordinated campaigns (updated based on change of RSCW timing agreed SWT 27)


  • PHI+EUI coordinated Offpointing Mosaic for Flatfielding with FDT and FSI (campaign details in TN-0019). (star)
    This campaign is tentatively scheduled at 2021-09-13T06:00:00Z - 2021-09-13T07:00:00 
    • Note EUI: will do two off-pointing mosaics, one for the EUI/FSI and PHI/FDT flatfield and a second flatfielding campaign for EUI/HRI, involving smaller offpoints (Sect 3 in TN-0019). 
      Both campaigns last 1 hr each (consistent with latest version of TN-0019)
    • SPICE_INTENSITY is scheduled during the off-pointings, may need to be shifted in time.
  • Limb Pointing RS-Alignment campaign (TN-0035) (star), tailored for high-resolution telescopes SPICE, PHI/HRT and EUI/HRI, involving limb pointings to N,S,E,W + disc centre. The whole campaign takes about 9 hours, based on SPICE durations of full scans. This campaign is tentatively scheduled at 2021-09-14T00:00:00Z - 2021-09-14T08:50:00.
    • Metis, SoloHI and STIX may need to adjust their timeline to take into account the SC manoeuvres.
  • S/C offpoints for SoloHI specific straylight calibration  (TN-0036(star)
    Tentatively scheduled at 2021-09-19T02:00:00 - 2021-09-19T07:30:00 
    • Note that during SOWG#14, the RSWG proposed to coordinate this campaign with Metis, as during RSCW1. Metis timeline to be adjusted.
    • EUI will participate in this offpointing campaign, with 3 EUI telescopes in parallel.
  • Limb pointing for SPICE's "out of field response" campaign involving a single "East" (wrt spacecraft) limb pointing (TN-0046(star) 
    The campaign takes 3 hours in total and is tentatively scheduled at 2021-09-19T08:00:00 - 2021-09-19T11:00:00. 
  • RS+IS SOOP to try out first coordinated science campaign, incl. VSTP cycle.
    L_SMALL_HRES_HCAD_SlowWindConnection SOOP scheduled from 16 to 19 Sep 2021.
  • At SWT24, the RSWG proposed to test out the SPROUT SOOP, i.e. out-of-window RS synoptics during the last day of RSCW4. Observations still to be added to the plan.
    • EUI already included a 6 hours of FSI_SPROUT on the last day of RSCW4 (+ flush).
  • EUI proposes to synchronize its observations with STEREO observations during RSCW 4 (almost the same LOS). Other instruments may be interested too, to be discussed during SOWG.

Note that there is an opportunity to "upgrade" RSCW4. Details are currently being iterated with the SWT.

Extra, special campaigns:

These address the opportunities identified during SWT 27 (listed in the table below). The activities taking place in the last 3 months - now LTP5 - have been greyed out and moved to LTP05 Oct 2021-Dec 2021

  • Remote sensing checkout window 4 has been moved to 12-20 September. (Affected instruments: ALL)
  • High rate observations have been added for the in situ instruments for the following periods (affected instruments: EPD, MAG, RPW, SWA):
    • 2021-08-02 - 2021-08-23 (VGAM, combined science with Bepi Colombo, Parker Solar Probe)
    • 2021-09-06 - 2021-09-27 (Perihelion; Radial Alignment with PSP, STA)
    • 2021-12-04 - 2022-01-01 (start nominal mission phase, plentiful downlink)
  • Remote sensing synoptic programme (based on L_FULL_LRES_MCAD_Coronal-Synoptic SOOP definition with additional SPICE observations included - to be reviewed) added during the following periods (affected instruments: EUI, Metis, PHI, SoloHI, SPICE, STIX):
    • 2021-08-30 - 2021-09-12 (close distance, prior to RSCW)
    • 2021-09-20 - 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)
  • Mercury moving through FSI FOV (2.63 Rsun) on 4 Oct, i.e. during the RS synoptics above. FSI may want to adjust the observations to take advantage of this opportunity.
  • Metis star calibration opportunities (note: data volumes are placeholders):
    • 2021-08-22 - 2021-08-25, τ Tauri
    • 2021-08-28 - 2021-08-30, HD36819
    • 2021-12-17 - 2021-12-26, θ Ophiuchi
  • Limb-pointing campaign (star) (following same format as alignment, TN-0035) for coordinated observations at quadrature between EUI/HRI and Earth assets. Tentatively scheduled on 2021-08-18, right after VGAM restriction 
  • S/C roll campaign (star) requested by Metis to for determination of vignetting function. This involves a full revolution around S/C+X, split into 18 rolls of 20º, with a dwell time at each position of 30 minutes. In total this campaign will last about 14 hours, tentatively scheduled on 2021-08-31 to not interfere with RSCW4 and the high-priority scientific opportunities listed in the table below.
  • 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 (affected instruments: PHI, SPICE, Metis, EUI, SoloHI)
  • 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.
  • 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 offpointing 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.

MLP: Changes from 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 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.

Table of Opportunities

This is a work in progress. Not all the opportunities described here may be addressed in the final operational plan. Those that have already been scheduled are included in the information above

Start DateEnd DateHeliocentric DistanceDescriptionInvolved InstrumentsConstraintsS/C manoeuvre required?
Cone geometry with BepiColombo

Support joint Bepi-SO Venus flybys (SO: 9 August, Bepi: 10 August)in-situ (TBC)VGAMno
2021-08-092021-08-09 +/- some weeks0.72 AU

Unique opportunity for science with PSP (best on 7-9 Aug for PSP perihelion), SOLO, BEPI, STEREO-A. SOLO & Bepi Venus flyby within a few days of each other.

PSP encounter will give radial and Parker alignments, also quadrature with SOLO & STEREO-A within a few days. RS observations in NAV window will be very important if this is possible. SOC will discuss with MOC.



(-20º roll)

no (in NAV window)

After Venus encounter?

or End RSCW4 / before EGAM?

MAG calibration rollsMAGTBC with flight dynamicsRolls


PSP spiral alignments for Solar Orbiter (for a 400 km/s wind)

In Situ

–20º rollno


UV star calibration τ Tauri (context plot, times)

Too faint for SPICE and EUI.


–20º rollno

UV star calibration HD 36819 (context plot, times)

Too faint and too far from disk for SPICE and EUI.

Metis–20º rollno


(Full month of September)

Proposal to plan RS synoptics throughout the month to support linkage with IS data and alignments with other spacecraft.
–20º, 0º, +20ºno



Solar Orbiter perihelion. Ideal opportunity for high cadence sequences of EUI, PHI, SPICE, ....

Ideal would be to adjust pointing reactively so we can link RS observations with IS measurements. This is the "dress rehearsal" in RSCW4.

All RS instruments

no roll (TBC by FD)




RSCW4 (8 days)


Nominal attitude required 
no SRP roll (TBC by FD)

Several campaigns involving Off-points
PSP-SO radial alignment  (also with STEREO-A for Sep 17-23)In Situ

Solar Orbiter at ideal angle to Earth to resolve 180º ambiguities in magnetic field

(S/C-Sun-Earth angle: 30º – 40º)

PHI + ...+20º rollno
2021-09-242021-10-080.6 AUBepiColombo Mercury flyby (1 Oct). Solar Orbiter is downstream of Mercury at the time.RS+20º rollno

2021-10-30 (before NAV)

or closer to 27 Nov (better alignment but in NAV)

SOC will discuss proposed dates with MOC

New date 5 Nov

~0.75 AU

(up to 1 AU depending on date)

Cross- and inter-cal opportunity with Earth-based assets (~1 day needed, mainly driven by PHI heating and switching telescopes).
Last chance for RS Ops before Nav window (TBD if concept changes).

To be decided whether we want to plan a secured campaign right before NAV window, or better centred on the Earth-Sun line with risk of last-minute replanning due to a TCM being planned by flight dynamics. 

New date 5 Nov, close to crossing Earth-Sun line (~2 deg latitude angle remaining)



+20º roll



UV star calibration θ Ophiuchi (context plot, times)

Too far from disk for SPICE and EUI.

2021-12-04± a few days
Emptying of SSMM for re-partitioning.


First month of NMP: Start of RS synoptic programme together with nominal IS science.All

Orbit plots courtesy of V. Andretta.

SOOP Kitchen plan

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

Starting point for LTP04 planning in SOWG#17: (WIP)

Final plan LTP04: to be added after SOWG#17 (April 2021)

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