Europa Lander Mission Study: Science Dave Senske (JPL) Deputy Europa Study Scientist OPAG March 29, 2012

Transcription

1 Europa Lander Mission Study: Science Dave Senske (JPL) Deputy Europa Study Scientist OPAG March 29, /29/12 23

2 Science from Europa s Surface For key habitability science, Europa surface materials must be sampled and analyzed in situ Geophysical and geological observations in situ would greatly advance Europa science The Europa Science Definition Team defined the highest priority science objectives, investigations, and measurements to be achieved from a Europa landed platform Aim for great science at low cost Art by Michael Carroll 3/29/12 24

3 Oct , 2011, JPL Europa SDT: Lander-Focused Meetings Developed initial objectives and investigations for a landed mission Nov , 2011, Boulder, Colo. Derived preliminary lander model payload and science mission requirements Jan. 31 Feb. 2, 2012, JPL Determined baseline vs. floor science and finalized lander model payload and mission requirements 3/29/12 25

4 Europa Science Definition Team Subgroup Structure Objectives subgroups: Ocean & Ice: Bills, Barr, Blankenship*, Connerney, Senske, Smith Composition: Blaney, Bagenal, Hoehler, Hand, Shock*, Brinckerhoff, Vance Geology: Moore, Kurth, McGrath, Mellon, Patterson, Prockter* Cross-Cutting subgroups: Astrobiology: Hoehler, Blankenship, Hand*, McGrath, Senske, Shock Instrumentation: Mellon, Bills, Blaney, Brinckerhoff*, Connerney, Kurth Landing Sites: Prockter, Bagenal, Barr, Moore, Patterson, Smith, Vance Bold = Lead; * = Deputy Lead 3/29/12 26

5 Science Goal, Objectives, and Themes Goal: Explore Europa to investigate its habitability Objectives: Themes: Composition: Understand the habitability of Europa's ocean through composition and chemistry Ocean & Ice Shell: Characterize the local thickness, heterogeneity, and dynamics of any ice and water layers Geology: Characterize a locality of high scientific interest to understand the formation and evolution of the surface at local scales chemistry water habitability energy 3/29/12 27

6 Lander Science Traceability Chemistry Emphasis Theme W Mass spectrometer, Raman C E spectrometer Goal Objective Investigation Model Instruments Explore Europa to investigate its habitability C. Composition O. Ocean & Ice Shell G. Geology Understand the habitability of Europa's ocean through composition and chemistry Characterize the local thickness, heterogeneity, and dynamics of any ice and water layers Characterize a locality of high scientific interest to understand the formation and evolution of the surface at local scales C.1 Characterize surface and near-surface chemistry, including complex organic chemistry to constrain ocean composition and understand the endogenic processes from which it evolves C.2 Characterize surface and near-surface chemistry, including complex organic chemistry to constrain the exogenic processes and material fluxes that affect ocean composition Mass spectrometer, Raman spectrometer C.3 Constrain the context of compositional measurements Site Imager, (Reconnaissance Imager), Microscopic Imager O.1 Constrain the thickness and salinity of Europa's ocean Magnetometer, Multi-band Seismometer Package O.2 Constrain the thickness of ice and the thickness of any water layers in the region Magnetometer, Multi-band Seismometer Package O.3 Search for local heterogeneity of the ice and any subsurface water Multi-band Seismometer Package O.4 Characterize Europa's seismic activity and its variation over the tidal cycle G.1 Constrain the processes that exchange material between the surface, near-surface, and subsurface G.2 Constrain the processes and rates by which the surface materials (regolith and bedrock) form and evolve over time Multi-band Seismometer Package Site Imager, (Reconnaissance Imager), Microscopic Imager Site Imager, (Reconnaissance Imager), Microscopic Imager G.3 Understand the regional and local context of the landing site Site Imager, (Reconnaissance Imager) G.4 Constrain the physical properties of the surface and near-surface at the (Reconnaissance Imager,) landing site to provide context for the sample Microscopic Imager, Engineering data Themes: W= Water, C = Chemistry, E = Energy 3/29/12 28

7 Traceability Example [Line across Trace Matrix here] Goal Objective Investigation Measurement Model Instrument(s) Mission constraints/ requirements Explore Europa to investigate its habitability C.1. Understand the habitability of Europa's ocean through composition and chemistry C.1a Characterize surface and nearsurface chemistry, including complex organic chemistry to constrain ocean composition and understand the endogenic processes from which it evolves Measure organic content of surface (0-2 cm depth) and near-surface (5-10 cm depth) materials to as low as 1 ppb concentration. Mass Spectrometer, Raman Spectrometer (1) Maintain the sample at a temperature to prevent melting (<198 K); to preserve O2, CO and CO2, the sample needs to be maintained at a temperature lower than 150 K; (2) Mass Spectrometer with capability for filtration, thermally evolved gas analysis, and organic separation; (3) Raman spectra of collected samples (lower sensitivity to organics than Mass Spectrometer); (4) Baseline: Mass Spectrometer and Raman measurements two samples from different depths; Raman and Mass Spectrometer to measure the same sample. Floor: Mass Spectrometer measurements of samples acquired from two depths; Europa Sampling System: Two samples of ~1 cc each. Obtain a minimum of one sample from cm depth, and one from 5 10 cm depth. Samples are not required to be from the same location. Contamination control of spacecraft organics in the sample analysis chain of < 1 ppb. 3/29/12 29

8 Model Instrument Mass Spectrometer (MS) Model Payload: Key Science Key Science Investigations and Measurements Surface and near-surface chemistry (especially organic content) to understand endogenic and exogenic processes and ocean composition. Raman Spectrometer (RS) Surface and near-surface chemistry (especially mineralogy) to understand endogenic and exogenic processes and ocean composition. Magnetometer (MAG) Multi-Band Seismometer Package (MBS) Site Imaging System (SIS) Microscopic Imager (MI) Reconnaissance Imager (RI) Ocean thickness and salinity; depth to local water layers. Thickness of ice and local water layers; local ice-water heterogeneity; seismic activity and variation over tidal cycle. Context of compositional measurements; material exchange processes; surface formation and evolution; landing site context. Context of compositional measurements; ice and non-ice grain characterization. Orbital context of lander observations. Floor model instrument Baseline model instrument 3/29/12 30

9 Lander Model Payload Mass Spectrometer (MS) Quadrupole MS connected to 2 ovens for evolved gas/pyrolysis Mass range: Daltons; Mass resolution: 1 Da over full range Raman Spectrometer (RS) Laser 976 nm; Spectral range 900 to 1500 nm (Raman shifts 0 to >3100 cm -1 ) Magnetometer (MAG) 3-axis vector, on 2 m boom Multi-Band Seismometer Package (MBS) 6 MEMS seismometers on lander legs; 3 well-coupled to ground 0.1 to 75 Hz (low-pass), Hz (high-pass), Site Imaging System (SIS) Dual stereo pixel framing cameras with filter wheel 0.3 m apart on 2-axis gimbaled platform on 1.5 m mast 360 azimuth range, ±90 elevation range Microscopic Imager (MI) pixels, 25 FOV, LED illuminators Galileo MAG Reconnaissance Imager (RI) Pushbroom imager, dual x 128 CCD arrays From 200 km altitude: 10 km x 10 km recon images at 50 cm/pixel Similar instruments ExoMars SP MSL MAHLI Huygens GCMS MER Pancam MRO HiRISE 3/29/12 31

10 Composition: Objective and Investigations Objective: Understand the habitability of Europa s ocean through composition and chemistry Investigations: Ocean composition and endogenic processes Exogenic processes and material fluxes Context of compositional measurements Art by Scientific American 3/29/12 32

11 Composition: Techniques Mass Spectrometry Characterize surface and near-surface organic composition and mineralogy to understand the habitability of Europa s ocean Determine the influx of exogenous organics and effects of Europa s radiation environment FeSO 4 7H 2 O à H 2 O + SO 2 CaCO 3 à CO 2 3/29/12 33

12 Composition: Techniques Raman Spectroscopy Characterize surface and near-surface inorganic chemistry to constrain ocean composition Measure the inventory of hydrated salts and other minerals in samples Characterize exogenous materials (e.g. Io silicates) Supplements mass spectrometer in characterizing organics 3/29/12 34

13 Composition: Techniques Imaging Constrain the context of compositional measurements by imaging the sample location Image collected samples at better than 100 µm 500 µm Phoenix lander 3/29/12 80 K H2O+H2SO4+MgSO4+H2O2 (K. Hand) 35

14 Ocean & Ice Shell: Objective and Investigations Objective: Characterize the local thickness, heterogeneity, and dynamics of any ice and water layers Investigations: 3/29/12 Thickness and salinity of Europa s ocean Regional ice and water layer thickness Local ice heterogeneity and subsurface water Seismic activity and its variation over the tidal cycle 36

15 Ocean & Ice Shell: Techniques Ocean characterization from magnetometry: Measure induction field (nt) at Jupiter rotation period (11 h), Europa orbital period (85 h), and other natural periods Ocean thickness and salinity can be uniquely derived over much of the likely parameter space Plasma effects may be an issue seawater nt nt (Khurana 2002) 3/29/12 37

16 Ocean & Ice Shell: Techniques Ice-ocean characterization from seismology: Determine ice shell and ocean thickness from reflected body waves Locate cracks, characterize the ice shell, and determine the frequency of energy release by observing reflected and refracted body waves ice-ocean interface ocean-mantle interface (Lee et al 2003) 3/29/12 38

17 Geology: Objective and Investigations Objective: Characterize a locality of high scientific interest to understand the formation and evolution of the surface at local scales Investigations: Processes that exchange material among surface, near-surface, and subsurface Formation and evolution of surface materials Regional and local context of landing site Physical properties of surface and near-surface as sample context 3/29/12 39

18 Geology: Techniques Site Imaging Characterize lander scale geologic processes and link to processes observed at regional and global scales Constrain rates by which surface materials (regolith and bedrock) form and evolve over time Provide context for sample site MER Pancam, Victoria Crater, Meridiani 3/29/12 Huygens, Titan HiRISE, Victoria Crater 40

19 Geology: Techniques 500 µm Microscopic Imaging Characterize ice and non-ice within sample to understand its heterogeneity, history, and context. 80 K H 2 O+H 2 SO 4 +MgSO4+H 2 O 2 Engineering data Sampling system data Landing system data Viking Lander 2 3/29/12 41

20 Landing Sites: Europa at a Small Scale Very limited information exists about surface at small scale from Galileo 15 images at 9 12 m/pixel 1 oblique image at 6 m/pixel Cassini Enceladus 4 m/pixel Galileo Europa 6 m/pixel 3/29/12 42

21 Landing Sites: Science Requirements Primary landing site characteristics are derived from the science objectives and ideally satisfy the following: Relatively young surface - Less radiation processing Evidence of recent activity - May imply recent communication with subsurface ocean Evidence of impurities - Low albedo regions likely contain impurities which are of higher astrobiological interest Potential to sample ocean material - Search for evidence of fluid extrusion on surface Potential for tectonic activity - Characterize seismic sources Relatively safe to land - Relatively smooth, and lower radiation Thera Macula, Europa notional landing ellipse 20 km 3/29/12 43

22 Landing Sites: Recommendations Candidate landing sites that best meet the science requirements are adjacent to, or within, regions of chaos Several candidate sites were chosen, which meet the science criteria and are outside the trailing hemisphere region of most intense radiation Electron Deposition Electron energy Depth of penetration (Patterson et al., 2012, submitted) 3/29/12 44

23 Model Payload: Key Accommodation Requirements Model Instrument Mass Spectrometer (MS) Raman Spectrometer (RS) Magnetometer (MAG) Key Accommodation Requirements Analysis of ~1 cm 3 samples from two depths, cm and 5 10 cm; sample temperature maintained at <198 K to prevent melting; sample at <150 K to preserve O 2, CO, and CO 2 ; contamination control in the sample analysis chain of of spacecraft organics to <1 ppb; inorganics to <1 ppm. Spectra of samples from cm and 5 10 cm; sample temperature maintained at < 198 K to prevent melting; sample at < 150 K to preserve O 2, CO, and CO 2 ; collect spectra of same samples collected for MS analyses. Continuous operations while on the surface for 3 Eurosols with a desire of 9 Eurosols; instrument isolated from the lander. Multi-Band Seismometer Package (MBS) Site Imaging System (SIS) Microscopic Imager (MI) Reconnaissance Imager (RI) At least three, three-components sensors, well coupled to ground; continuous data monitoring for 3 Eurosols with a desire of 9 Eurosols; minimize lander noise at seismometer frequency range; knowledge of seismometer position and orientation. Ability to survey landing site in stereo from near-field to horizon; unobstructed and lit view of sampling area. Ability to access acquired samples; imager and target in close proximity for data taking; image same samples collected for MS and RS analyses. Low altitude orbit to achieve at least 50 cm/pixel coverage of landing site; ability to resolve lander and correlate images with those from site imager. Floor model instrument Baseline model instrument 3/29/12 45

24 Europa Lander Science: Summary Europa lander enables unique in situ science opportunities The most definitive way to probe Europa s composition as relevant to habitability Organics and salt chemistry Exogenic vs. endogenic materials Would provide extremely valuable geophysical and geological science Ocean salinity and thickness Seismic activity and ocean-ice structure Geological processes at a human scale Though very limited information exists about surface at lander scales, promising targets can be identified Art by Michael Carroll 3/29/12 46