PSJC #2 Jan 16 2008
MARCO POLO Mission and Proposed Work
MARCO POLO is a near-Earth object sample return mission to a primitive
asteroid whose objective is to return samples that are otherwise not
available among known meteorites. Primitive bodies are leftover building
blocks from the earliest era of Solar System formation and may have
contributed water and organics to Earth, thereby providing a foundation
for life. Primitive meteorites are among the least frequently sampled by
falling to Earth and all samples received are biased by their ability
to survive atmospheric passage. Direct investigation of both the fresh
regolith and fresh lithospheric fragments is also impossible by any
means other than sample return. MARCO POLO will conduct a broad in situ
analysis of the target and the geologic context for the samples prior to
their acquisition. Sample return enables the power of the Earth's
laboratories to identify major chronological events in solar system
history, to search for pre-solar material yet unknown in meteorite
samples, and to characterize in depth the nature of organic compounds
that may be present. MARCO POLO thus directly addresses the top level
NASA strategic planning goal to: Advance scientific knowledge of the
origin and history of the solar system, the potential for life elsewhere,
and the hazards and resources present as humans explore space (NASA
Science Plan 2007, page 5).
Proposed Work by US Investigators During
Assessment Phase: The MARCO POLO proposal presents four mission options,
whose scientific return and scientific merits are to be assessed relative
to the total mission cost. A major component of the proposed work by
US Investigators will be to contribute to the full identification and
development of the science return for each mission option and to more
fully demonstrate the scientific case for the MARCO POLO mission relative
to NASA's objectives. The four mission options are:
In addition to the scientific assessment of the mission options,
US Investigators will participate in the evaluation and groundbased
reconnaissance of potential mission targets. Current targeting options
for the MARCO POLO mission include the following near-Earth objects:
Mother spacecraft (MSC), separate surface lander (SIFNOS), capability
for multiple sampling and full recording of the sample acquisition, a
re-entry capsule, and scientific payloads for in situ characterization.
- Add a subsurface drilling capability to the SIFNOS lander.
Perform the landing, sampling, and drilling by a single spacecraft
(no separate lander).
- Touch & go sampling by the MSC only, with
Particularly important to the success of the MARCO POLO mission is the
placement of the target body and sample within the broad context of
the solar system. While groundbased measurements can access numerous
small solar system bodies, only very few bodies can be directly sampled
by missions. Thus the context of the sampled body, within the broader
solar system population, must be understood as part of the scientific
assessment for the MARCO POLO mission. The team of 12 US investigators
named within the ESA proposal, and their proposed contributions during
the assessment phase, are summarized in Table I
[not included --Ed.]. The members of the
US investigator team have the background and the capability to bring
specific strengths and contributions to the MARCO POLO mission during
the assessment phase. These strengths and contributions, include:
(4015) Wilson-Harrington, a dormant comet, that can provide insights
into the unknown link between asteroids and comets;
D-type asteroids such as 2002 AT4 and 2001 SG286;
- The primitive
C-type double asteroid 1996 FG3, which in addition to early solar
system history, provides insight into the binary formation process.
- Evaluation of the science return of the mission options and the mission
targets, as described above, to make a final recommendation on overall
mission design. The resulting science return can be affected to ensure
alignment with NASA objectives.
- Capabilities and experience to:
perform groundbased reconnaissance of the proposed targets (as well as
potential new ones), to evaluate and model existing data on targets,
and to use the derived information on target characteristics as critical
input for the final mission design. These physical observations have the
capability to characterize the radius, albedo, thermal inertia, shape
and surface composition of the potential targets based on visible and
- Carry out laboratory analysis of primitive
meteorites for a wide variety of grain sizes to try to estimate the
mineralogy surface characteristics (and possible organic chemistry)
of the potential targets, where this understanding will impact mission
design and target selection. These analyses will include spectroscopic,
x-ray diffraction, and x-ray fluorescence measurements.
- Apply knowledge from current photometric models, and develop new ones,
specific to the low albedo surfaces to be encountered for MARCO POLO
mission targets. These model results will be used to set sensitivity
requirements for remote sensing instrumentation and will affect mission
planning (e.g. exposure times) so as to achieve the target and sample
characterizations specified within mission options.
of the reconnaissance phase imaging requirements to achieve a global
characterization of the target asteroid, particularly with regard to its
cratering distribution and inference of its likely collisional history.
- Expertise in the mechanical properties of asteroid regoliths,
the modeling, and the design of experiments for various possible
surface structures, and the effects of those properties on the surface
interactions; including anchoring, drilling and sample collection.
Expertise in planning and implementing procedures for the collection,
return, and recovery of samples. Additional expertise to prepare a more
extensive description and plan for sample handling and curation.
Evaluation of the mission design requirements to achieve the acquisition
of samples most likely to supply the detailed solar system chronology
central to the overall mission science objectives.
List of References Documenting Expertise to be Contributed by