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:

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

Science and calibration planning

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

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


Note that there is an opportunity to "upgrade" RSCW4 → the original timeline from MLP has been upgraded with factor 5 in TM during SOWG #17 - Apr 2021

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

(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: (bookmarked version used for pre-SOWG#17 simulation)

What’s changed since the end of the SOWG?

Following the intensive planning exercise, a few items have been tidied up and several simluations run so that we could arrive at a valid long-term plan in SOOP Kitchen:

Released plan version

Final plan LTP04 (V2): : Baseline 8 / version 2584.

Planning products V2 distributed on  via GFTS.