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

2. 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)

3. 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

4. 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)

5. ACK Phase (1 Nov 2006– 1 Jan 2007) Latest MPCORB file:
asteroids osculating OE at Epoch:
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

6. 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

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

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

9. 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 = AU
31 Mar 2007
Rsc = AU
Selected asteroids: P < AU, A > AU
863 SELECTED NUMBERED ASTEROIDS

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

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