Title: Mars Aeronomy Science Themes and the NASA Exploration Initiative Report from the NASA Mars Aeronomy
1Mars Aeronomy Science Themes and the NASA
Exploration InitiativeReport from the NASA Mars
Aeronomy Working Group
- Bruce Jakosky (Chair)
- (bruce.jakosky_at_lasp.colorado.edu)
- 17 September 2004
2Overview Mars Upper Atmosphere, Mars Science,
and the Exploration Initiative
- Determining the history of the Martian climate,
the chemical weathering and alteration of the
surface, and the planets habitability requires
understanding the roles of the solar wind and
solar radiation inputs the physics, chemistry,
and dynamics of the upper atmosphere and the
escape of volatiles to space. - The upper atmosphere plays important roles in
programmatic aspects of the Mars exploration
program, including communications, energetic
particle and radiation environments that can
affect humans, the lifetimes of orbiting
spacecraft, operational aspects of orbital
missions, and aerobraking operations. - Some limited observations of the upper atmosphere
are being made at present, and the Mars
Telecommunications Orbiter has the potential to
make further contributions, but the desired
understanding can best be obtained from a
dedicated upper-atmosphere mission.
3Mars Aeronomy Working Group
- Chartered by NASA to explore science and
programmatic issues related to the Mars upper
atmosphere in light of recent discoveries and the
new exploration program. - Combined effort of (then) Solar System
Exploration Division and Sun-Earth Connection
Division (both now part of the Science Mission
Directorate). - Activity requested by the Directors of the two
divisions. - Working group created to lead discussion,
organize and run a workshop that would bring
together the aeronomy community, the
exploration initiative connections, and the rest
of the Mars science community, and create a
white paper reporting back on the results.
Workshop had nearly 90 participants. - Discussions of NASA Code S personnel with working
group chair on 13 May 04, workshop held on 18-19
August 04, draft powerpoint report circulated
within working group and then distributed to
community for comments, and finalized on 17
September 04.
4Mars Aeronomy Working Group (Steering Group)
Membership
- Bruce Jakosky, Univ. of Colorado (chair)
- Stephen Bougher, Univ. of Michigan
- Randy Gladstone, Southwest Research Inst.
- Joe Grebowsky, NASA/GSFC
- Rod Heelis, Univ. of Texas at Dallas
- Jennifer Trosper, NASA HQ
- Andrew Yau, Univ. of Calgary
- Richard Zurek, NASA/JPL
- Key NASA HQ participation
- Mary Mellott, SEC
- Denis Bogan, SSED
- Bill Peterson, SEC
5Key Components of Working Group Charter
- Reexamine the upper-atmosphere science questions
and determine whether and how they should be
revised in response to the new vision. - Understand which operational requirements of the
Exploration Systems Division involve this region
and what further understanding is required. - Summarize the opportunities available for support
of the study of this region, including those
associated with the upcoming Mars Scout and Mars
Telecommunications Orbiter opportunities.
6MARS AERONOMY EXPLORATION WORKSHOP AGENDA, 18-19
August 2004 (Agenda and powerpoint presentations
available on web, at http//argyre.colorado.edu/l
ife/aeronomy_workshop) Wednesday, August
18 800-830 Coffee 830-845 Workshop
introduction B. Jakosky 845-855 NASA HQ
perspective, SEC division M. Mellott 855-905 NA
SA HQ perspective, SSE division D.
Bogan 905-925 Mars program and NASA HQ D.
McCuistion 925-955 Status of the Mars
Program M. Meyer 955-1020 Code T requirements
and interest J. Trosper 1020-1035 Break 1035-
1050 Mars Telecommunications Orbiter R.
Zurek 1050-1105 Mars Scout opportunities K.
McBride 1105-1130 MEPAG Goals and Objectives
for upper atmosphere S. Bougher 1130-1145 Lesson
s learned from MGS and Odyssey aerobraking S.
Bougher 1145-1200 Lessons learned at
Venus A. Nagy 1200-1215 MGS Magnetometer
results D. Mitchell 1215-130 Lunch All 1
30-145 Lessons learned at Earth from Earth
missions S. Yee 145-200 Preliminary results
from Mars Express ASPERA J. Sharber
7Wednesday, August 18, continued 200-515 Discus
sion on these topics - Are the aeronomy
science goals and objectives balanced, complete
, appropriate, etc.? (S. Bougher) - How
do they relate to the rest of the Mars
program? (R. Gladstone) - Can MTO
contribute to aeronomy science goals? (R.
Zurek) - What measurements/analyses are
required prior to human missions? Can they be
obtained via a science-oriented Scout or do
they require a dedicated mission? (J.
Trosper) 515-545 Integration and wrap-up B.
Jakosky
8Thursday, August 19 800-830 Coffee 830-1200 C
ontinue discussion from before, with these added
topics - What actions/resources from HQ are
required to further develop these topics? -
What are the recommendations from the group as a
whole? - Wrap-up of open workshop 1200-115 L
unch 115-500 Closed session of steering group
to draft report 500 Adjourn
9Long-Recognized Need for Upper-Atmosphere
Measurements
- In-depth study of Mars upper atmosphere
consistently has been judged necessary to
understand the evolution of Mars and other
planets. - Upper-atmosphere missions have been the subject
of several advance mission studies and was a
defining element of the ill-fated Japanese Nozomi
mission. - COMPLEX (National Research Council Committee on
Planetary and Lunar Exploration) has consistently
given an aeronomy mission high value within
planetary science. - NRC Decadal Survey (New Frontiers in the Solar
System An Integrated Exploration Strategy,
2003) includes Mars upper atmosphere studies as
an important component of an overall program. - MEPAG (Mars Exploration Program Activity Group)
2004 prioritized ranking of science goals and
objectives gives high priority to
upper-atmosphere studies as they pertain to
evolution and control of planetary habitability.
10Ongoing and Planned Measurements From Orbit
Relevant to the Upper Atmosphere
- Mars Global Surveyor (MGS) Magnetometer/Electron
Reflectometer (MAG/ER) measurements (ongoing) - MGS radio occultation (ongoing)
- Mars Express ASPERA (neutral particle imaging,
neutral particle detection, electron
spectrometer, ion mass analyzer ongoing) - Mars Express SPICAM (atmospheric occultation
ongoing) - Mars Express MARSIS (long-wavelength radar
antenna not yet deployed) - Mars Reconnaissance Orbiter (MRO) aerobraking
data - MRO radio occultations
- Requires resoliciting the Radio Science
investigation or implementing a funded
Participating Scientist program in a timely
manner. - While these will provide valuable science and
operations data, they will not, taken together,
provide the understanding of the upper atmosphere
structure, composition, dynamics, and variability
necessary to address the pertinent science
questions.
11Relevant Areas for Additional Study Other than
from Spacecraft
- There is a need for new chemical rate
coefficients and cross-section data existing
data are old, out of date, and inconsistent. - Some science issues can be addressed very
effectively using telescopic observations from
Earth these are complementary to spacecraft
measurements. Ongoing and recent analyses
include observations from HST, FUSE, and IRTF, as
examples. - Studying stellar winds and UV output in Sun-like
stars at various ages will help us infer the
history of martian interactions with the Sun, and
thereby its climate history and volatile
evolution.
12Key Areas Identified and Discussed
- How do the Mars upper-atmosphere and aeronomy
issues relate to the rest of the Mars science
program? - Are the current aeronomy science goals and
objectives balanced, complete, appropriate, etc.? - How can the Mars Telecommunications Orbiter
contribute to aeronomy science goals? - What measurements/analyses are required prior to
human missions? Can they be obtained via a Scout
mission designed to address science goals or do
they require a dedicated mission or missions?
13Scientific Connections Between Studies of the
Upper Atmosphere and the Rest of the Mars Program
(1 of 2)
- Mars as an integrated system The martian
volatile, climate, and habitability system is
an integrated one, from below the surface to
above the exobase. Atmospheric dynamics,
surface-atmosphere volatile exchange, and the
climate cannot be understood without determining
the role of the upper atmosphere. - Loss of martian water and volatiles The history
of the martian atmosphere and climate over time
cannot properly be understood without knowing the
role of loss of water and other volatiles to
space. These will affect our general
understanding of the nature of planetary
habitability in general and habitability of Mars
in particular. - Evolution of surface and atmospheric chemistry
Formation of surface weathering deposits (such as
the sulfates at the Mars Exploration Rover (MER)
Opportunity site, or carbonates there and
elsewhere) depends on atmospheric composition and
oxidation state interpretation of chemical and
isotopic composition requires understanding
atmospheric effects.
14Scientific Connections Between Studies of the
Upper Atmosphere and the Rest of the Mars Program
(2 of 2)
- Follow the dust theme The lower and upper
atmosphere are tightly coupled. Atmospheric
structure and change in the escape over time of
volatiles to space may result from lower-upper
atmosphere connections, electrodynamic response,
and dust event heating in the lower atmosphere
potential importance for exploration missions
(see below). - Interpreting magnetic fields Crustal magnetic
field measurements are used to improve our
understanding of the evolution of Mars' interior
and crust. Crustal magnetic fields and
variations in external forcing all affect upper
atmospheric processes, with plasma-neutral
coupling a key player, and upper-atmospheric
properties thereby affect our ability to measure
and understand magnetic fields. - Comparative planetology By examining the same
processes in the different environments of the
three terrestrial planets, we can better
understand how they work and better apply them to
understanding planetary evolution.
15Influence on the atmosphere and climate via the
role of escape to space shown here.
16Connections between loss of volatiles to space
and other components of the Mars
climate/surface/interior system (Arrows show
which components of the system directly affect
other components)
17Are the Aeronomy Science Goals and Objectives
Balanced, Complete, Appropriate, etc.? (1 of 2)
- The recent Mars Exploration Program Analysis
Group (MEPAG) Science Goals and Objectives
document describes the areas that should be
addressed by upcoming missions. Following
discussion, the workshop participants concluded
that - The specific MEPAG goals and objectives
articulated in the document - Address key, high-priority issues in aeronomical
science - Can frequently only be achieved by making
measurements which are traditionally viewed as
aeronomical in nature - The MEPAG investigations listed under the
objectives should - Note that several required aeronomical
measurements can be made with Earth-based
observations ( e.g., from earth-orbiting or
ground-based platforms) and/or in situ
measurements - Consider the potential role of atmospheric
electrical properties - The MEPAG listed investigations should strengthen
emphasis on - Dust impact on the entire atmosphere (including
aerosol charging) - Plasma-neutral coupling
- External drivers at the top of the atmosphere
(e.g., solar radiation and particle effects) - Implications of the crustal magnetic fields and
their interaction with upper atmospheric
processes over time
18Are the Aeronomy Science Goals and Objectives
Balanced, Complete, Appropriate, etc.? (2 of 2)
- What role do upper-atmosphere missions play in
the Pathways architecture? - Concern was expressed over how an
upper-atmosphere mission fits within the
Pathways concept described in Mars Exploration
Strategy, 2009-2020, published in 2003 by the
Mars Science Program Synthesis Group - An aeronomy mission was called out in only one of
the four pathways (never any water, in which it
was a forced fit), and recent science results
from MER appear to have rendered that pathway
moot. - All need to be reminded that the pathways were
examples to show the diversity of potential
missions and mission architectures and the
ability of the science program to respond to new
discoveries. It was not a menu of four options. - Aeronomy/upper-atmosphere studies address key
science objectives for Mars, ensuring that a
mission in this area is credible and appropriate
within any actual architecture.
19How Can the Mars Telecommunications Orbiter (MTO)
Contribute to Aeronomy Science Goals? (1 of 2)
- The theme recommended by the MTO Science
Definition Team, of Mars environmental
monitoring is supported. - It appropriately takes advantage of the expected
long lifetime of MTO, potentially to observe the
behavior of components of the upper atmosphere
over a full 11-yr. solar cycle. - It could provide the solar cycle context in
which a shorter-lived upper-atmosphere mission
could provide the detailed coverage of physical
and chemical processes related to volatile
evolution and therefore climate change. - Example candidate instruments for long-term
monitoring include - Radiation fields, including Solar Energetic
Particles (SEPs) and Solar UV irradiance - Atmospheric emissions from which composition can
be inferred - Solar-wind interactions at the 4000-km MTO
orbital altitude - Atmospheric dust and temperature structure to
high altitudes - Ionosphere electron density profiles.
20How Can the Mars Telecommunications Orbiter (MTO)
Contribute to Aeronomy Science Goals? (2 of 2)
- Notes with regard to MTO
- MTO radiation measurements would enhance similar
and contemporaneous measurements on the Mars
surface. - Spacecraft-to-spacecraft radio occultations would
broaden coverage of atmospheric neutral and
ionospheric structure beyond that attainable by
MTO alone. - Magnetic field measurements can significantly
enhance interpretation of the SEP and pick-up-ion
distribution measurements that would address the
proposed Mars space environment monitoring. - The measurements obtainable within the
constraints imposed by MTO (instrument mass,
power, available funding, viewing geometry, s/c
orbit, etc.) are such that no plausible
instrument selection would allow us to check the
box that MTO has made the aeronomy measurements
necessary to understand key volatile escape
processes and their current rates.
21Human Exploration Program Considerations(1 of 2)
- Upper-atmosphere studies have the potential to
play important roles in the following areas - Understanding the human-related radiation
environment and the relationship between the
radiation incident on the upper-atmosphere and
the surface radiation hazard. - The role of the ionosphere in communications
links. - Lifetime of orbital instruments and platforms and
related planetary protection concerns, and
operational aspects of orbital missions at
moderate altitudes that still feel the effects of
the upper atmosphere (such as reaction wheel
desaturation operations). - Aerobraking operations and hazards associated
with upper-atmosphere structure and variability
including dust influence, variability, and
evolution.
22Human Exploration Program Considerations(2 of 2)
- Understanding the influence of the upper
atmosphere in these areas requires knowledge
(observation and modeling) of the - Diurnal variability
- Seasonal variability
- Solar-cycle variability
- Spatial (geographical) variability
- Altitude variability (including effects from the
lower atmosphere) - It is necessary to establish measurement
requirements in terms of a well-defined risk and
mitigation strategy (i.e., whether the system can
handle the potential variations vs. simultaneous
observations to allow optimization and control). - Upper-atmosphere studies do support aerobraking
of robotic missions, but may not be needed for
aerocapture due to the low altitude of primary
deceleration (30-50 km) expected for human
missions.
23Ongoing Participation and Responsibility of the
Aeronomy Community
- Making the scientific connections between the
Mars upper atmosphere and the broad Mars science
goals via a science traceability matrix is the
responsibility of any proposer for instruments or
missions. - Mars Express results are relevant to the upper
atmosphere and to evolution processes, and need
to be incorporated into any discussion of science
results and proposals for future instruments or
missions. - Generally, the Mars aeronomy/upper-atmosphere
community has not been heavily engaged in MEPAG
activities, and as a result the potential
contributions of aeronomical science to achieving
high-priority Mars science goals and objectives
have not been incorporated as thoroughly as they
could be. - The discussion represented by this workshop and
white paper needs to be the first of an ongoing
dialog and integration of the community, not a
one-time activity.
24Summary Recommendations and Conclusions
- The upper atmosphere is an important part of the
martian climate system. Understanding the
behavior of the key components of the system
(such as surface habitability or geochemical
evolution) will require understanding the entire
system from the interior to the exobase. - Important aspects of the upper-atmosphere can be
observed from the unique perspective of MTO,
especially with observations potentially made
over an entire solar cycle. - Although some notable observations of the upper
atmosphere are being made at present, they are
limited in scope and coverage and do not provide
the detailed information necessary to address the
major science and programmatic issues. - The necessary observations can be made from a
dedicated s/c mission with appropriate orbit,
lifetime, and instrumentation. The necessary
observations are thought to be possible within
the constraints of a Scout mission, although
detailed analysis of this opportunity has not
been done.