S. Rafkin, Southwest Research Institute (rafkin@boulder.swri)

1. Filling Mars Human Exploration Strategic Knowledge Gaps with Next Generation Meteorological Instrumentation. S. Rafkin, Southwest Research Institute (rafkin@boulder.swri.edu) D. Banfield, Cornell University R. Dissly, Ball Aerospace Corporation This work has been supported in part by NASA PIDDP NNX12AK49G-S02

2. MOTIVATION Analysis of Strategic Knowledge Gaps Associated with Potential Human Missions to the Martian System Precursor Strategy Analysis Group (P-SAG) (jointly sponsored by MEPAG and SBAG) Review copy released May 31, 2012 Review comments received from MEPAG, CAPTEM, SBAG, from community discussions at the LPI Workshop (June 12-14), and from MPPG (June 21) Final report June 30, 2012 Recommended bibliographic citation: • P-SAG (2012) Analysis of Strategic Knowledge Gaps Associated with Potential Human Missions to the Martian System: Final report of the Precursor Strategy Analysis Group (P-SAG), D.W. Beaty and M.H. Carr (co-chairs) + 25 co-authors, sponsored by MEPAG/SBAG, 72 pp., posted July 2012, by the Mars Exploration Program Analysis Group (MEPAG) at http://mepag.jpl.nasa.gov/reports/.

3. Examples of Atmospheric Gap-Filling Activities Measurement Priorities There are other atmospheric GFAs identified in the P-SAG report.

4. Intent of Atmospheric SKGs • Need to characterize the structure and dynamical behavior of the atmosphere. • Need to validate models of the atmosphere. • Need to improve models of the atmosphere. • Need to extrapolate observations to other locations with models. Rafkin et al.

5. Why Investigate? Q: What is the density and wind structure at time of landing? A: I don’t know. Here’s a guess. Q: What are the error bars? A: I don’t know. Here’s a guess. Q: Why don’t you know? A: Because the proper payloads have not been flown. Q: So, we’ll have to keep guessing for this and future missions? A: Yes. Rafkin et al.

6. Decision More of the same will do little to make significant progress on the atmospheric SKGs. Atmospheric SKG Goals major? or Present state Incremental? Knowledge Humans on Mars MSL Viking Phoenix 2020 Pathfinder Time / Surface Experiments Rafkin et al.

7. An Upward Knowledge Trajectory: Forcing Mechanisms Change in Internal Energy = Temperature (response) T-> p -> Winds Energy In (forcing) Energy Out (forcing) Infrared Down Infrared Up Sensible Heat Flux Latent Heat Flux Solar Down Regolith Heat Flux Rafkin et al.

8. An Upward Knowledge Trajectory: Forcing Mechanisms Change in Internal Energy = Temperature (response) T-> p -> Winds Energy In (forcing) Energy Out (forcing) Infrared Down Infrared Up Sensible Heat Flux Latent Heat Flux Solar Down Regolith Heat Flux Measuring only T, p, V response provides ambiguous information for reconciling and improving errors in models. Rafkin et al.

9. Density Errors Due to Turbulent Flux Density errors of a few percent are significant for entry, descent and landing. Rafkin et al.

10. Density Errors Due to Turbulent Flux Density errors of a few percent are significant for entry, descent and landing. Rafkin et al.

11. By Measuring Forcing: • Better characterize the structure and dynamical behavior of the atmosphere. • Better validate models of the atmosphere. • Improve models of the atmosphere. • More confidently extrapolate observations to other locations with models. Rafkin et al.

12. By Measuring Forcing: • Better characterize the structure and dynamical behavior of the atmosphere. • Better validate models of the atmosphere. • Improve models of the atmosphere. • More confidently extrapolate observations to other locations with models. • Make significant progress on SKGs! Rafkin et al.

13. Necessary Measurements • Pressure, temperature, winds (response). • Radiative Forcing: solar and infrared . • Dust opacity (radiative forcing). • Heat and momentum fluxes (turbulent forcing). Rafkin et al.

14. Necessary Measurements • Pressure, temperature, winds (response). • Radiative Forcing: solar and infrared . • Dust opacity (radiative forcing). • Heat and momentum fluxes (turbulent forcing). Flight Heritage Rafkin et al.

15. Measuring FluxesSonic Anemometer + Tunable Diode Laser Earth Mars field prototype Mars environmental testing in early Fall. (TRL-6). Mars flight engineering model CBE Resources 0.3 kg sensor 2 kg electronics 4 W Rafkin et al.

16. Fluxes Sensible Heat Flux = Latent Heat Flux = Momentum Flux = All depend on composition, which varies for Mars. Density from T and p. T from speed of sound, which depends on composition. Measuring 3-D winds, Cs, p, and composition provides a closed system of equations. Measurements must be colocated and measured at high frequency (>10 Hz) due to small size of eddies near the ground. Rafkin et al.

17. Accommodation • A perfect instrument poorly accommodated makes a poor experiment. • Must ensure proper accommodation. • Must minimize spacecraft contamination: • Mechanical • Thermal • Extended booms are the most likely solution. Want to measure this, not this. Rafkin et al.

18. Summary • New measurements with proper instrument accommodation are needed to achieve many atmospheric SKGs. • Previous instrumentation and methods are insufficient. • Cannot be done exclusively from orbit. • Quantify forcingand response. • Turbulent fluxes are a key forcing mechanism. • Simultaneously measuring p, T, V, bulk composition, and solar and IR fluxes provides an energy closure experiment. • Atmospheric state must be measured at >10 Hz. • Most instrumentation is high heritage and low resource. • Combined sonic anemometer and tunable diode laser at TRL-6 this Fall. Rafkin et al.