1. Defining the Preferred case
Action 7 CLOSED_SWT35: SWT to define decision process to define HAC or LAC based approach. Deadline next SWT.

2. Defining the Preferred case
Summary of discussion
As discussed at the last SWT.
We decide which trajectory to follow for the rest of mission –
Either a scaled HAC or a scaled LAC
Scaled HAC
LTP1
LTP2
LTP3
Decide based on activity
measurements
Scaled LAC
LTP1
LTP2
LTP3

3. Defining the Preferred case
Summary of discussion
As discussed at the last SWT.
We decide which trajectory to follow for the rest of mission –
Either a scaled HAC or a scaled LAC
Scaled HAC
Decide based on activity
measurements
HAC
Scaled LAC
Outgassing
LAC
Heliocentric dist. (AU)

4. Defining the Preferred case
From this, a list of items that were iterated via in February within the SWT (two similar lists).

5. Preferred case 1) We have to get the actual activity value
1) The SWT propose which pre-landing measurements will be used to define cometary activity
2) Consider criteria for defining the preferred case (make feedback into 1) 
3) The SWT agree criteria for either a scaled HAC or scaled LAC (and hence retain the agreed segmentation).
Last November we discussed % of HAC or reference to the Snodgrass predictions): close to Snodgrass - go for scaled LAC, close to 40% LAC - go for scaled HAC.
4) The SWT define how to monitor evolution of activity and hence the way the scaling works (to avoid being forced to jump to the HAC unnecessarily).
5) Define a schedule for trajectory group interactions.
1) We have to get the actual activity value 
2) We have to decide what we do with this value (projection into future): go for modified LAC, modified HAC 
3) We have to monitor the actual value and compare it to the projected one.
4) In case of deviations we have to decide what to do.

6. Preferred case 1) We have to get the actual activity value
2) We have to decide what we do with this value (projection into future): go for modified LAC, modified HAC 
3) We have to monitor the actual value and compare it to the projected one.
4) In case of deviations we have to decide what to do.

7. Preferred case 1) We have to get the actual activity value
2) We have to decide what we do with this value (projection into future): go for modified LAC, modified HAC 
3) We have to monitor the actual value and compare it to the projected one.
4) In case of deviations we have to decide what to do.
Summer 2014 would provide measurements of:
The nucleus mass and density.
The gas production rates.
Anything else?
Based on 1, we must determine which projection into the future to utilize and how to implement the projection (i.e. how to scale one of either the HAC or the LAC).
There is no scope for defining a third option.

8. 1) We have to get the actual activity value 
2) We have to decide what we do with this value (projection into future): go for modified LAC, modified HAC 
Activity = 110 % LAC
Go for Scaled LAC, where scaling is 120% LAC.
Preferred case
HAC
Preferred case= 120% LAC
Outgassing / elephants per furlong
LAC
August
2014
Heliocentric dist. (AU)

9. Preferred case 1) We have to get the actual activity value
2) We have to decide what we do with this value (projection into future): go for modified LAC, modified HAC 
3) We have to monitor the actual value and compare it to the projected one.
4) In case of deviations we have to decide what to do. On LTP timescales
Carry out monitoring of activity versus projected activity.
For LTP004, this will provide expected uncertainty of outgassing.
However, if the projected value is wrong, is there anything that can be done?
Is this simply a transition to the HAC if we got it wrong?
We have to make a very good choice at 2.

10. For LTP4, TRAL delivery by late September
3) We have to monitor the actual value and compare it to the projected one.
4) In case of deviations we have to decide what to do. On LTP timescales
For LTP4, TRAL delivery by late September
LAC
HAC
LTP7 ?
Preferred case= 120% LAC
Outgassing / elephants per furlong
LTP6
LTP5
LTP4
August
2014
LTP7 TRAL
LTP6 TRAL
LTP5 TRAL
LTP4 TRAL
Heliocentric dist. (AU)

11. For LTP5, TRAL delivery mid November
3) We have to monitor the actual value and compare it to the projected one.
4) In case of deviations we have to decide what to do. On LTP timescales
For LTP5, TRAL delivery mid November
LAC ?
HAC
LTP7
Outgassing / elephants per furlong
LTP6
LTP5
LTP4
August
2014
LTP7 TRAL
LTP6 TRAL
LTP5 TRAL
LTP4 TRAL
Heliocentric dist. (AU)

12. For LTP5, TRAL delivery mid November
3) We have to monitor the actual value and compare it to the projected one.
4) In case of deviations we have to decide what to do. On LTP timescales
For LTP5, TRAL delivery mid November
LAC
HAC
LTP4 Preferred case= 120% LAC
Measured activity lower
LTP5 Preferred case = 110% LAC?
LTP7
Outgassing / elephants per furlong
LTP6
LTP5
LTP4
August
2014
LTP7 TRAL
LTP6 TRAL
LTP5 TRAL
LTP4 TRAL
Heliocentric dist. (AU)

13. Defining the Preferred case
Skeleton planning for LTP –
In March we will require approval of HAC trajectory by trajectory group.
Propose this is done via simply .
Impact of updated comet information on HAC should be minimal.
For LAC we should also consider approval of LAC trajectory in May timeframe.
Once comet is better constrained in August, update of trajectory where appropriate is carried out, TRAL update and iteration with skeleton group to check consistency.
Beginning of September, Trajectory group approve trajectory and final TRAL created.

14. Defining the preferred case
Key point is what can be refined in TRAL given the small timescale?
Decisions are required in a 6 week window for LTP4.
We need to define the mechanism and decision making process at this meeting or within 1-2 weeks after.
I think realistically these tweaks are covered by the following:
orbit altitude, flyby altitude and length of time we believe bound orbits are possible.
DISCUSS…

15. CONCLUSION
Preferred case:
An outgassing value to be used to scale the LAC must be determined by August 2015.
Suggestion that small team of Instrument representative + IDSs gather prior to that date to provide this value.
This then scales the LAC.
This value is derived each week to examine evilution of activity to feed into next LTP.

16. Had two options – use scaled LAC OR scaled HAC.
Baseline scaled LAC. If activity in summer is 150% LAC – Scaled HAC is used.
Question is # bound orbits – can a RSGS provide quick analysis of scaling versus bound orbit number.
An outgassing value or activity level to be used to scale the LAC must be determined by August 2014.
Group made up of ROSINA, Virtis, MIRO and ALICE with support of the IDSs report to PS and provide an activity level, APREF1.
APREF1 used to scale the LAC for LTP004.
This will provide us with a certain number of bound orbits.
In September and October, group made up of ROSINA, Virtis, MIRO and ALICE with support of the IDSs report to PS and look at evolution of A biweekly, in November provide value APREF2
September SWT meeting provides an opportunity to examine evolution from APREF1 as a broader group.
APREF2 used to scale the LAC for LTP005.

18. Extra slides

19. ALAC is activity level of LAC in August 2014
APREF1 is activity level determined in August 2014
APREF1used to scale the LAC for LTP004.
Outgassing
APREF1
ALAC
LAC
August
2014
Heliocentric dist. (AU)

20. Outgassing / elephants per furlong
HAC
APREF2 A6 A5
Outgassing / elephants per furlong A4 A3 A2 A1
APREF1
LTP5
LTP4
August
2014
LTP7 TRAL
LTP6 TRAL
LTP5 TRAL
LTP4 TRAL
Heliocentric dist. (AU)

21. HAC
Snodgrass
Outgassing / elephants per furlong
LAC
August
2015
Heliocentric dist. (AU)