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LTS phase: from end of FSS (mid Nov. 2014) to end of Rosetta mission (31 Dec. 2015), i.e. from ~3AU before to 2AU post-perihelion limiting factor may be lifetime of PHILAE, rather than ROSETTA (current estimates: ~2 AU pre-perihelion?)
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LTS phase: from end of FSS (mid Nov. 2014) to end of Rosetta mission (31 Dec. 2015), i.e. from ~3AU before to 2AU post-perihelion limiting factor may be lifetime of PHILAE, rather than ROSETTA (current estimates: ~2 AU pre-perihelion?) SC objectives: Objective 8 = long-term science (but also other PHILAE objectives are followed up during LTS) LTS science objectives: all PHILAE experiments have LTS science objectives HBO expectation: FSS gives a taste of cometary science, LTS provides synopsis of cometary science for future text book chapters LTS phase: the LS standpointprepared by HBO PHILAE Science Team, Venice 2009
PHILAE Science Objectives A P X S C I V A C O S A C C O N S E R T M U P U S P T O L E MY R O L I S R O MA P S D 2 S E S A M E O1 Nucleus structure & composition LTS-005 SDL-001, FSS-001, FSS-002 LTS-001, LTS-002, LTS-004 FSS-001, FSS-002, LTS-002 LTS-003, LTS-004 O2 Surface & sub-surface composition FSS-001 LTS-001 SDL-001, FSS-001, FSS-002 FSS-003, LTS-001, LTS-002 LTS-003, LTS-004 FSS-003 LTS-003 FSS-001 FSS-002 LTS-002 LTS-003 LTS-004 FSS-006 LTS-007 O3 Surface structure & physical properties FSS-003 LTS-003 SDL-001, SDL-0002, FSS-001 FSS-002, FSS-004, LTS-001 LTS-002 SDL-001 SDL-002 FSS-001 LTS-001 LTS-002 LTS-001 SDL-001, FSS-001 FSS-002, FSS-003 FSS-003, FSS-006 LTS-001, LTS-002 LTS-003, LTS-007 O4 Nucleus interior SDL-001, FSS-001, FSS-002 LTS-001, LTS-002, LTS-004 SDL-001 O5 Comet – plasma interaction FSS-001 LTS-001 ICEP-004 SDL-004 FSS-007 LTS-008 O6 Dynamic processes ICEP-002 FSS-001 LTS-001 ICEP-001, ICEP-002, ICEP-003, ICEP-004, SDL-002, SDL-004 FSS-004, FSS-007 FSS-008, LTS-004 LTS-005, LTS-008 O7 Thermal & mechanical properties & mass transport SDL-001, FSS-003, FSS-004 FSS-005, LTS-001, LTS-003 LTS-004 SDL-001, SDL-003, FSS-001 FSS-005, LTS-001 LTS-006, LTS-007 O8 Long-term evolution of landing site properties FSS-001 LTS-001 FSS-004 FSS-005 LTS-001 LTS-004 FSS-008, LTS-001 LTS-002, LTS-003 LTS-004, LTS-005 LTS-007 O9 Interrelation with orbiter measure-ments FSS-001 LTS-001 FSS-001 FSS-004 LTS-001 ICEP-001,ICEP-002, SDL-001,, FSS-001, FSS-001, FSS-002 LTS-001, LTS-002, LTS-003 SDL-001 SDL-002 ICEP-001, ICEP-002, ICEP-003 SDL-002, SDL-003, SDL-004 FSS-008, LTS-004 PHILAE Science Team, Venice 2009
LTS phase minimum success criterion: measurements for at least four about equally distributed solar distances when the comet approaches the Sun from 3 to 2 AU, i.e. between mid Nov. 2014 to end March 2015 2.75, 2.5, 2.25, 2.0AU ~ once a month reasoning: non-linearity of T increase, gas & dust production (strong increase of H2O plus organics), change of surface structure, decoupling of cometary surface from interaction with solar wind, day-night cycle sampling by ‘more than 3 data points LTS + FSS should cover activity onset by at least 5 measurements per experiment for the characterization of the comet behaviour LTS phase: the LS standpointprepared by HBO PHILAE Science Team, Venice 2009
Experimenters’ expectations: typically every 0.1AU ~ once every two weeks (also more frequently) possibly a mixture of more continuous measurements (MUPUS, ROMAP, SESAME) and periodic ones (APXS, CIVA, COSAC, PTOLEMY, ROLIS, SD2) and campaign-like ones (CONSERT) might be a reasonable approach An updated thermal model of PHILAE would be useful to have LTS phase: the LS standpointprepared by HBO PHILAE Science Team, Venice 2009
LTS operation modes: operation modes defined by LTS engineering group survival is prime aspect science and battery charging are key aspects trade-off between short-term science and long-term prospect of science through battery usage is important it is worthwhile considering science by a low power user instead of continuous battery recharging at inefficient level expectation: MOST tool allows the analysis the Lander LTS operation options experimenters have to accept that lander survival and long-term science prospect rules over immediate experiment objectives LTS phase: the LS standpointprepared by HBO PHILAE Science Team, Venice 2009
Impacts on SDL & FSS phases: SDL - landing site selection should consider optimized location for LTS, i.e. from solar illumination and power point of view FSS – consider – as an option - battery usage for early LTS operations phase (@ 2.75AU) Landing site selection: * safety of descent, landing and survival * scientific criteria * operational criteria LTS phase: the LS standpointprepared by HBO PHILAE Science Team, Venice 2009