# Presentation: 525685

## Earth, Lunar and Planetary (Mars) Environments-Group D

- Key questions:
- -What we know
- -What we don’t know (and need to know for VSE)
- -How do we address the above?
- Considered for:
- -Earth environment
- -Lunar Orbit and Surface
- -Mars Orbit and Surface

## Earth Environment: What we Know

- Rad Belts:
- -LEO, GEO models with solar cycle variations
- -Observations of SEP injections
- -COSPAR, ILWS  studies and recommendations
- -SPENVIS and other Models for space systems effects available
- -Observational archives including science data and space systems anomalies
- Plasma
- -Observational archives
- -No (known) comprehensive model
- -NASCAP program developed and widely used for effects modeling
- Ionosphere/Upper Atmosphere
- -Models of Neutrals and Ionosphere- EUV dependent and geomagnetic activity dependent
- -Observational archives-ground and space-based
- -Documented effects on satellite orbits, communications

## Earth Environment: What we Don’t Know and Need to Know for VSE

- Rad Belts:
- -Dynamic models including SEPs and heavy ions, extremes of behavior
- -Predictive rather than statistical models
- Plasma:
- -A substantial global model for use in updated NASCAP
- -Dynamic Models including extremes
- -Predictive rather than statistical models
- Ionosphere/Upper Atmosphere:
- -dynamic models including EUV flare responses, particle input responses
- -Predictive rather than statistical models

## Earth Environment: How do we get there?

- Develop Dynamic, Predictive Model Development in all areas: Rad belts, Plasma Environment, Ionosphere/Upper Atmosphere, e.g. coupled system models of geospace (magnetosphere, upper atmosphere/ionosphere, rad belts) parameterized by solar EUV and driven by solar wind
- Provide necessary data-mining infrastructure to do the above, together with new observations targeted toward this goal (e.g. LWS RBMP, ITMP)- for both model parameterization and validation  (note using these  effectively requires solar and upstream interplanetary supporting information)
- Use Earth high-latitude upper atmosphere as a local “laboratory” for Mars (to investigate matters from atmospheric transport code validations with balloon experiments, to studying responses of a thin atmosphere to solar photon and particle inputs expected at Mars
- Collaborate/cooperate/sponsor joint studies and investigations with like-minded programs with similar goals- especially LWS Program (form a joint MOWG?)

## Lunar Environment: What we Know

- A variety of information from past relevant observations on Explorer 35, Apollo, Clementine, Lunar Prospector, Geotail, and WIND spacecraft on plasma and field environment, crustal magnetic fields, lunar surface charging, dust, lunar atmosphere (also remote detections), SEP events and dosimetry at the Moon
- Surface neutron information from Lunar Prospector, plus surface neutron models (SIREST transport codes and others). Relevant surface composition information from Clementine, LP, lunar samples.
- Lunar radiation exposure history from Lunar Samples (another group’s prime interest)

## Lunar Environment: What we Don’t Know and Need to Know for VSE

- Sufficiently Comprehensive space environment description from observations and (validated) models (“be there (in the VSE human-carrying mission orbits) before you get there”)
- Sufficiently Comprehensive lunar surface environment description from observations and (validated) models (“be there (on the lunar surface where VSE explorers will land) before you get there”)
- Need to define “Sufficiently Comprehensive”

## Lunar Environment: How do we get there?

- Restore (as necessary) existing lunar environment data (including Apollo, Clementine). Convene a splinter group to revisit these and all existing environment data relevant to VSE from all sources – to re-establish environment knowledge base
- Install  more comprehensive lunar surface models in surface radiation environment codes
- Determine (now) whether LRO measurements will sufficiently validate models of  the radiation environment in orbit and on the surface. Determine what further orbital and surface measurements are needed (e.g. neutron, dust, electric field measurements on the Lunar Robotic Lander) to establish environment knowledge for human expeditions. Fly LRO.

## Mars Environment: What we Know

- GCR and SEP Primaries and Secondaries-
- -primaries much like 1 AU for GCR,  SEP events slightly attenuated with radial distance
- -secondaries (on surface) only modeled with transport codes (e.g. SIREST, which requires other surface and atmosphere models)
- -transport code validation experiments conducted on ISS and with HEND on Odyssey
- -SEP events detected in Mars orbit show modifications introduced by Mars
- Ionosphere/Upper Atmosphere-
- -Previous and new measurements show dynamic, structured, variable systems
-  (depending on season, dust, crustal magnetic fields,  solar EUV flux, solar wind conditions, etc.)
- -Models exist: GCMs and TGCMs for lower and upper atmosphere, and
-  more limited ionosphere models. Upper atmosphere models are used in Mars mission aerobraking plans.

## Mars Environment: What we Don’t Know and Need to Know for VSE

- Validation of orbit and surface radiation environment models  and transport codes, for both spectrally hard (GCR) and softer (SEP) components.
- Validation of Atmosphere and Ionosphere models  to be used in applications. (Upper atmosphere models  used in entry and orbital planning, ionosphere models  considered in communications technologies planning.) Validation requires supporting solar and interplanetary data together with upper atmosphere/ionosphere measurements.
- “Be there before you get there” –emulate VSE situations.

## Mars Environment: How do we get there?

- Validate radiation transport codes- e.g. on stratospheric balloons, on Mars surface. Determine if MSL measurements are sufficient for the latter. (e.g. Lack of upstream measurement of local SEP fluxes and spectra are limiting. Codes need to be validated in both hard and soft spectral ranges.) Convene a splinter group to answer this question, make recommendations?
- Initiate a special initiative to Collect and synthesize the full range of  available atmospheric and ionospheric measurements relevant to VSE orbiters and Landers, and to make  model improvements to include all significant parameters  (e.g. dust, flare effects, etc.). Make on-orbit and surface measurements to validate models in areas of VSE interest, including  orbital evolution and craft entry, and on-surface operations (e.g. dust, E and B fields effects, ionospheric conditions relevant to communications and operations).
-  Coordinate plans, activities with Mars Exploration Program where appropriate and advantageous.

## Timeline Considerations-examples

- Near term:
- -Radiation Transport codes updates, upgrades
- -stratospheric balloon radiation transport codes validation
- -Lunar data restorations and synthesis activity
- -data mining infrastructures: Earth, Lunar and Mars
- -Mars atmosphere data collection and synthesis specific to VSE needs
- - Radiation environment and Atmosphere/Ionosphere Model developments based on data mining and ongoing observ.

- In process/ mid-term
- -LRO
- -MSL
- -RBMP, ITMP
- -supporting solar/helio missions
- -Earth Radiation environ. and Lunar and Mars Surface radiation model validations
- Future/or need study
- -Mars upper atmosphere characterization missions
- -Mars upstream solar monitoring or validated models

## Session D “other discussion”

- Need to acknowledge, learn from, and communicate with the wide range of groups conducting and generating overlapping activities/studies/reports (e.g. MEPAG, LWS, other NRC committees, COSPAR, ESA Geospace, Mars and Lunar study groups and missions, Roadmap groups (SSP and SSE), astrobiology community).
-  Concern that the myriad of groups and reports may be confusing or conflicting, or efforts needlessly redundant, or relevant good ideas, results, and/or opportunities from others not folded in to VSE’s and NASA’s advantage.

## Conclusions slides from Group D presentations

## Conclusions

- Surface radiation calculations have been performed for the Earth’s moon, Mars, and Callisto
- These calculations show that radiation shielding will be an important consideration in planning of long term missions to these surfaces
- These calculations also demonstrate the large variation in exposure rates due to solar cycle
- The advantages of using shielding materials containing hydrogen were demonstrated
- The ability of the HZETRN code to calculate the radiation environment on the surface of any planet or moon has been demonstrated

- M. Clowdsley presentation

## Conclusions

- The Martian surface environment including albedo neutrons can be calculated using existing transport codes
- These codes must be validated with detector data!!!!!!

- M. Clowdsley

## What we know about effects of SEPs and solar flares on the ionosphere/upper atmosphere:

**SEPs cause > 2 orders of magnitude increase in Ne in the D-region**
**Causing long-term changes of neutral composition in the mesosphere and upper stratosphere**
**Thermospheric temperature, neutral density, and TEC all increase in the thermosphere due to flares**

**What we don’t know:**
** ****How deep SEPs can penetrate to the Mars upper atmosphere**
**The short and long-term effects: how different or similar compared to the terrestrial upper atmosphere/ionosphere**

**What we need to get there:**
**	****Using comprehensive observations to constrain GCMs for Mars**

- Gang Lu

## and for that report...

- What we know:
- There are large potentials on the lunar surface, especially in shadow, especially in the plasma sheet.
- Does not depend on surface characteristics (terrain & surface ages)
- What do we need to know?
- Surface electrical characteristics.
- Magnetospheric boundary prediction.
- Plasma sheet temperature predictions.
- How do we get there?
- Comprehensive surface environment investigation.
- Dynamical magnetospheric model to forecast plasma sheet boundaries, temperatures, based on solar/solar wind observations.

## Geotail observations are the main source of energetic particle data in the lunar environment – analyze!
Lunar Prospector provide data as background count rates
Need to restore Clementine data set

Need more sampling at higher energy ranges (10> MeV)

Meanwhile: ongoing efforts to model and understand SEP access into magnetosphere (CISM, UCLA group)

- Lunar Prospector provide data as background count rates
- Need to restore Clementine data set
- Need more sampling at higher energy ranges (10> MeV)
- Meanwhile: ongoing efforts to model and understand SEP access into magnetosphere (CISM, UCLA group)

- C Lee

## We Need:

- To develop new empirical, but dynamic, climatological models
- To understand which processes operate and when
- A second equatorial satellite orbit and low-altitude precipitation measurements to significantly extend the science return from RBSP (as identified by the GMDT)
- To develop global physical models that provide context for observations as well as predictive capability
- Integrate new & continuing observations with these new tools

- G. Reeves

## Radiation Transport Model Validation

**Optimal experiment design should be derived from a science-based collaboration of**** **
**Transport modelers **
- (Where do models agree, disagree? What are they most sensitive to?)
**Experimentalists **
- (What can be measured? How well? At what cost?)
**Experts in Mars atmosphere, surface and subsurface**
- (How much can the location of the measurement impact the results?)
**Radiation-environment community **
- (What components of the environment have the largest impact on humans/systems?)

- R Turner

## Summary

- The surface radiation from a large SPE can be important compared to the surface radiation from GCRs.
- Crustal fields do not strongly effect SEPs reaching the Martian surface.
- Crustal fields can have a significant effect on atmospheric energy deposition during a SPE, driving chemistry and dynamics
- (  Proposal to continue this work submitted to Planetary Atmospheres  )
- Also:
-     Relationship discovered between the presence of intense auroral-like electron distributions and SEP events at Mars

- D Brain

**Notes:**
This is a summary for Part 2 of the presentation only