The OSIRIS Solar System Simulator (OSSS) and its application to ACK and MFB phases Bertini Ivano

The Osiris SS Simulator (OSSS) Collection of programs (IDL, Matlab): orbital propagator re-building the geometry of the SS in a S/C-centred RF at the date of interest (asteroids, planets, Sun) Scientific Purposes: Calibrations (stellar background determination) Fast identification of the targets Search for small satellites of target asteroids (OSIRIS scientific goal) Observational strategy for Asteroid Flybys Search for targets of opportunity (close asteroids)

ASTEROIDS Orbital Elements (MPC Orbital Database) T0 SUN and PLANETS positions (JPL DE2000) Ti Orbital Propagation Cowell Method S/C position (FDG) Ti Asteroids+Sun+Planets S/C-centred positions Ti ASTEROIDS positions Ti Geometric and Photometric data: m, (α,δ), PA, SEA WHAT IS DETECTABLE & WHERE IT IS Targets of opportunity FLYBYs Observing Strategy

Search for close asteroids MPS request: search for asteroids closer than 10Mkm to Rosetta (eventual targets of opportunity) We will show: Results for ACK (Nov 2006 – Jan 2007) Results for Mars FB ( Jan – Mar 2007)

ACK Phase (1 Nov 2006– 1 Jan 2007) Latest MPCORB file: asteroids osculating OE at Epoch: 6 3 2006 120437 NUMBERED asteroids Computational time T = T (Δtprop, Nast) e.g. all numbered asteroid propagated in 8 months period (one single date) => T ~ 5 hrs Exigence of propagate orbit of only the asteroids that can be 10Mkm close to S/C

Initial Orbital Selection Selected Orbit: P<Rmax, A>Rmin Rmin Rmax Not taking into account i ! Case single date: Rmin=Rs/c-10Mkm, Rmax=Rs/c+10Mkm Case entire phase: Rmin=Rs/cmin-10Mkm, Rmax=Rs/cmax+10Mkm

Rosetta heliocentric distance ACK Phase Rosetta heliocentric distance 1 Nov 2006 Rsc = 1.01393AU 1 Jan 2007 Rsc = 1.22005AU Selected asteroids: P < 1.28690 AU, A > 0.94708AU 412 SELECTED NUMBERED ASTEROIDS

Results ACK Phase Only asteroid 87024 gets closer than 10Mkm (9 – 20 Dec): dmin ~ 7.23Mkm

Rosetta heliocentric distance Mars FB Phase (MFB 25 Feb 2007) We considered the time range 1 Jan – 31 Mar 2007 Rosetta heliocentric distance 1 Jan 2007 Rsc = 1.22005AU 31 Mar 2007 Rsc = 1.53567AU Selected asteroids: P < 1.60251 AU, A > 1.15321 AU 863 SELECTED NUMBERED ASTEROIDS

Only asteroid 26663 closer than 10Mkm Results Mars FB Phase Only asteroid 26663 closer than 10Mkm (28 – 31 Mar 2007)

Further Actions Extend to other mission phases (SFB and LFB Results in tomorrow presentation) Change 10Mkm range? Including comets Suggestions…