1. Pre-landing Orbiter Observations
ROSETTA SWT Meeting #25
Working Group 1
Pre-landing Orbiter Observations
Holger Sierks
Max-Planck Institut für Sonnensystemforschung

2. Agenda WG #1 Meeting Introduction
Invitation of ESOC reps on landing strategy (& power)
Lander requirements, decision tree for landing
Discussion on feasibility constraints and risks
Status of instrument iteration concerning requ observations
Status of FD (Flight Dynamics) modeling
Review of Action Items
Upcoming activities (e.g. instrument mtgs)
Interaction with WG#3
Data sharing policy
AoB

3. Summary WG1 Meeting #1
ESOC member is needed for flight dynamics (engineering) - established
keep chair/wo/men of WG2 and WG3 in cc in all communications - established
target: first cut prepared within 6 months – negative
distribute WG team lists (all WG w/ ) - ok, list to be checked
V Dhiri will be i/f to ESOC - established
need WG agenda for upcoming WG mtgs - established
documents review -> to come
- landing nominal at 3AU on Nov 10, 2014
- 60+7days Wirtanen case timeline, timeline options to be discussed
- goals: refine pre-landing timeline
refine release strategy
define required resources
- 1st cut of list of scientific requirements of knowledge of nucleus, gas environment, dust/grain environment, mapped to instrument coverage
- CReMA is good starting point
- policy needed to share (unique) data within science team

4. Summary WG1 Meeting #1 cont’d
- use Earth swing-by 3 as demonstrator
- responsibility for dtm creation (ESA/Osiris)
- risk assessment to convince ESOC to get as close as needed to release the lander
- logistics, co-location for data analysis important, modeling essential
- decision tree for landing needed, evalution risks for pre-landing observations
Actions:
- prepare list of actual documents (action to ESOC/RSOC)
- review required distances for the contributing instruments
- update /team list by to chairs
- logistics/timeline: only, wrap up at next swt
- mass estimation vs time or distance needed from ESOC with RSI
Next meeting:
- instruments to present core sensitivities
- ESOC to prepare document/strategy presentation
- propose ESB common observations
prepared summary of potential instrument contributions to support landing
Summary WG1 Meeting #1 cont’d
- use Earth swing-by 3 as demonstrator
- responsibility for dtm creation (ESA/Osiris)
- risk assessment to convince ESOC to get as close as needed to release the lander
- logistics, co-location for data analysis important, modeling essential
- decision tree for landing needed, evaluation risks for pre-landing observations
- prepared summary of potential instrument contributions to support landing
Actions:
- prepare list of actual documents (action to ESOC/RSOC)
- review required distances for the contributing instruments
- update /team list by to chairs
- logistics/timeline: only, wrap up at next swt
- mass estimation vs time or distance needed from ESOC with RSI
Next meeting:
- instruments to present core sensitivities
- ESOC to prepare document/strategy presentation
- propose ESB common observations

5. Landing Prerequisites (as of SWT 23)
Physical parameters of C-G (size, mass, density)
Rotational axis and rotational modes
Shape model of nucleus
Activity profile(s)
Surface properties at various pixel scales
Thermal properties
Chemical/mineralogical composition, model of the top surface
Inner coma and dust environment
Landing strategies

6. Summary WG1 Meeting #2
WG#1 is pre-cursor to WG#2 and WG#3 activities. Requirements to accuracies (expected from the instruments) are tailored for safe orbiter approach and lander delivery.
Action: A mtg of WG#1 reps with ESOC is needed to consolidate the constraints
in comet approach and lander delivery. The timeline shall be reviewed
and the Crema strategy explained.
Discussion on level of detail and accuracy required from the instrument teams to allow FD (Flight Dynamics) to get closer and lander dare to land. Requirements to be worked from FD and lander side to forward to the instruments for feasibility assessment to achieve required accuracies.
Next step is instrument by instrument review on prep of required observations in an iterative process. This process was started already with Miro.
FD will develop (simplified) environmental (dust, gas) and dynamic model for safe approach. Interaction with imager and dust instruments is requested.

7. Summary WG1 Meeting #2 cont’d
Action: There are 2 lander documents available on safe landing parameters. AI to distribute in WG#1 team and to FD.
Osiris can contribute to comet detection allowing early wake up, thus buying time for comet approach. Impact and potential to be checked.
Dedicated instrument mtgs to be setup with all contributing instruments (Rosina, Virtis, Osiris, Cosima, Radio Science, Alice, RPC,..) to close the loop and understand requirements and constraints for lander delivery and pre-requisites.
Alice and Miro can provide the pressure by limb observation. Concurrent observation may be helpful. Miro and Virtis Earth observations can be compared for x-calibration (action tbc).
AI to define power constraints during comet approach phase. Full power is available only at 3.25AU. Wake-up is at 4.49AU on 22 Jan Jan to May is commissioning of s/c subsystems. p/l will be commissioned starting gradually in April Instrument activation, checkout strategy and planning is needed and get phased in. Work in solar opposition date starting June 25 lasting till 22 July Constraints to be checked on potential blinding and thus schedule impact.

8. Agenda WG #1 Meeting Introduction
Invitation of ESOC reps on landing strategy (& power)
Lander requirements, decicion tree for landing
Discussion on feasibility constraints and risks
Status of instrument iteration concerning requ observations
Status of FD (Flight Dynamics) modelling
Review of Action Items
Upcoming activities (e.g. instrument mtgs)
Interaction with WG#3
Data sharing policy
AoB