European Space Agency Agence Spatiale Européenne directorate of operations and infrastructure ground systems engineering department mission analysis office MAO Working Paper No. 483 Issue 1, Rev. 0 Solar Orbiter Ballistic Transfer Mission Analysis Synthesis by Guy Janin and Arnaud Boutonnet November 2005 European Space Operations Centre Robert-Bosch-Str. 5 D - 64293 Darmstadt SOLAR ORBITER BALLISTIC TRANSFER MISSION ANALYSIS SYNTHESIS MAO Working Paper No. 483, Issue 1.0 PAGE INTENTIONALLY LEFT BLANK ii ESOC Mission Analysis Office s November 2005 SOLAR ORBITER BALLISTIC TRANSFER MISSION ANALYSIS SYNTHESIS Abstract This Working Paper summarises mission analysis performed for the Solar Orbiter mission using chemical propulsion only. This mission is composed of a cruise phase allowing reaching a low solar orbit, followed with an inclination increase phase allowing viewing the Sun at high latitudes. The Solar Orbiter, to be launched by a Soyuz/ST + Fregat from Kourou, performs Deep Space Manoeuvres using a monopropellant propulsion unit combined with planetary Gravity Assist Manoeuvres. An optimum transfer trajectory is calculated, leading to a 150-day orbit in a 3:2 resonance with the period of Venus and an initial perihelion radius of about 48 solar radii. During an extended part of the mission, through repeated gravity assist manoeuvres with Venus, the orbit inclination is raised without use of propulsion. Transfer duration is 3.5 years and end of nominal mission occurs 6 years after launch. Maximum inclination in excess of 34° is reached 9.5 years after launch. Launches during the 2013, 2015, 2017 and 2018 Venus launch window opportunity are investigated. For the 2017 launch, the planetary configuration is less favourable, the cruise phase is longer and only a 4:3 resonant orbit with Venus can be initially reached. As a consequence, the end of nominal mission occurs 7.6 years after launch. An analysis of the navigation tasks to be performed before and after the Venus gravity assist manoeuvres during the Science phase shows that they can be performed by the AOCS at a cost of about 15 m/s per gravity assist manoeuvre. This report, available in MS-Word and PDF format, contains colour figures. s ESOC Mission Analysis Office iii SOLAR ORBITER BALLISTIC TRANSFER MISSION ANALYSIS SYNTHESIS MAO Working Paper No. 483, Issue 1.0 PAGE INTENTIONALLY LEFT BLANK iv ESOC Mission Analysis Office s November 2005 SOLAR ORBITER BALLISTIC TRANSFER MISSION ANALYSIS SYNTHESIS Table of Content 1. INTRODUCTION............................................................................................................1 1.1 The Solar Orbiter Mission ...................................................................................... 1 1.2 Mission Design...................................................................................................... 1 1.2.1 Transfer and Inclination Raise Phase............................................................... 1 1.2.2 Mission Phases .............................................................................................. 2 2. TRANSFER PHASE........................................................................................................3 2.1 Gravity Assist Manoeuvres .................................................................................... 3 2.2 Mass Budget for Ballistic Launches in 2013 to 2018 ................................................ 3 2.3 2013 Launch......................................................................................................... 5 2.4 2015 Launch........................................................................................................13 2.5 2017 Launch........................................................................................................20 2.6 2018 Launch........................................................................................................28 2.7 Launch Window ...................................................................................................29 3. INCLINATION INCREASE.............................................................................................31 3.1 Procedure for Inclination Increase.........................................................................31 3.2 Maximal Inclination Raise and Propellant Usage.....................................................32 4. NAVIGATION .............................................................................................................35 4.1 Introduction..........................................................................................................35 4.2 Models and Assumptions ......................................................................................35 4.2.1 Spacecraft....................................................................................................35 4.2.2 Measurements ..............................................................................................35 4.2.3 Covariance Analysis......................................................................................36 4.2.4 Guidance Algorithm.......................................................................................36 4.3 Simulation Results ................................................................................................37 4.3.1 Navigation Before the Second Venus Swing-by ..............................................37 4.3.2 Navigation Between Second and Third Venus Swing-bys ................................40 4.4 Feasibility of the Manoeuvre Execution..................................................................42 4.5 Conclusion of the Navigation Analysis ...................................................................43 5. LAUNCHER’S PERFORMANCE .....................................................................................45 6. CONCLUSION .............................................................................................................47 7. REFERENCES ..............................................................................................................49 s ESOC Mission Analysis Office v SOLAR ORBITER BALLISTIC TRANSFER MISSION ANALYSIS SYNTHESIS MAO Working Paper No. 483, Issue 1.0 List of Tables Table 2-1. Ballistic mission DV and mass budget for a launch in 2013, 2015, 2017 and 2018 with a monopropellant propulsion unit with specific impulse 220 s. The spacecraft dry mass is given in the last row, column headed kg...................................................................................... 4 Table 2-2. Ballistic mission timeline for a launch in 2013. ........................................................... 5 Table 2-3. Distance to Sun centre in AU and solar radii, spacecraft inertial orbit rotation rate and rate relative to the rotating Sun in °/day in terms of the perihelion passage number, passage date and flight time........................................................................................................... 8 Table 2-4. Ballistic mission timeline for a launch in 2015. ..........................................................13 Table 2-5. Distance to Sun centre in AU and solar radii, spacecraft inertial orbit rotation rate and rate relative to the rotating Sun in °/day in terms of the perihelion passage number, passage date and flight time..........................................................................................................16 Table 2-6. Ballistic mission timeline for a launch in 2017. ..........................................................20 Table 2-7. Timeline comparison between Venus GAM 1 and 2 for the 2015 and 2017 transfer. Flight times and duration between two consecutive GAMs are in days. Last column shows the increase in duration between the 2017 and 2015 case. .......................................................21 Table 2-8. Distance to Sun centre in AU and solar radii, spacecraft inertial orbit rotation rate and rate relative to the rotating Sun in °/day in terms of the perihelion passage number, passage date and flight time..........................................................................................................24 Table 2-9. Ballistic mission timeline for a launch in 2018. ..........................................................28 Table 4-1. Description of the arcs analysed in this working paper. GAM V2: 2nd Venus swing-by. GAM V3: 3rd Venus swing-by. ........................................................................................35 Table 4-2. Trajectory correction manoeuvres statistics before the second Venus encounter (GAM V2)................................................................................................................................37 Table 4-3. Evolution of the 1s dispersion covariance matrix at pericentre projected on the target plane (GAM V2). ...........................................................................................................38 Table 4-4. Trajectory correction manoeuvres statistics between the second and the third Venus (GAM V3). ....................................................................................................................40 Table 4-5. Evolution of the 1s dispersion covariance matrix at pericentre projected on the target plane (GAM V3). ...........................................................................................................40 vi ESOC Mission Analysis Office s November 2005 SOLAR ORBITER BALLISTIC TRANSFER MISSION ANALYSIS SYNTHESIS Table of Figures Figure 2-1. Ballistic