Progress report four for the
On-Planet team for Friday March 03, 2000
For this week’s progress the On-Planet team continues
the research required for experimentations to be conducted on the planet once
the astronauts arrive.
1) Landing on the Surface
Landing Sites
Once the astronauts enter the
atmosphere our main objective is where to land. In our second progress report we chose several Martian landing
sites that should be considered. In
total, according to NASA Reference
Publication 1238, the Landing Site Catalog, there are approximately 153 possible landing sites. For a list of these sites you may visit:
http://cmex-www.arc.nasa.gov/MarsTools/Mars_Cat/Mars_Cat.html
We propose to have a
target-landing zone near the equator.
One good target zone is the place where the pathfinder landed, near the
Ares Vallis region – a region scarred by ancient water channels. Or the HEBES CHASMA site, which is excellent
for analysis of soil because of the sediment, layered walls.
Surface Operations
Once
there, the primary activities, of course, are the setup, organization and
systems check of the surface equipment.
Mission Support should have a design whereby the habitat and laboratory
modules can easily be attached together and powered by the nuclear power
module. The crew will then be able to
conduct the previously planned experiments immediately after all equipment has
been set up. Since this is going to be
about a 500-day mission, we have provided a list of vital Martian experiments
to be conducted in our previous progress reports and later in this report. The findings from these experiments will
likely determine the direction of further investigations.
The
geology and mineralogy of the surrounding area will be investigated and the
search for evidence of life, either past or present, will continue. Since this will be a two-crewed mission,
each team will coordinate with each other and look for water in the Martian
soil. The crew will report their
experiences on the surface of Mars back to mission control. The crew will also have leisure and
“vacation” time so that they can appreciate the experiences of being the first
humans to walk on Mars.
2) More experiments involving on-planet experimentation
Nuclear Magnetic Resonance
NMR studies the atoms or molecules with nuclear spins.
From interactions with electrons and neighboring nuclei, NMR spectra of
molecules show unique lineshapes or chemical shifts. This information can be
used for characterization purposes. Also by completing NMR spectroscopy one can
obtain information about the constituent nuclei and chemical structure of
molecules. Specific applications of NMR on Mars include presence of water in
the soil, minerals and rocks; free water in rock pores; absorbed water on
surface; and chemically bound water.
Also by utilizing proton-NMR, one can determine the
quantity and physical and chemical nature of water (ex. H20, OH) in geological
samples. Proton NMR is operated .1-1 g samples in an applied magnetic field by
irradiation of radio frequency (~ 13 MHz at ~ 3 kGuass) to induce transitions
between proton spin states.
INSTRUMENTS REQUIRED:
miniature magnetic resonance spectrometer (<
500
g, < 5 W) with combined capabilities of EPR
and
NMR (being developed at JPL), a
proton-NMR
spectrometer
X-RAY FLUORESCENCE
ANALYSIS (XRF)
This is a bulk chemical analysis method. Bulk chemistry
of single mineral grains can provide important clues to their identity and in
addition to other structural data identification is almost assured. One of
these instruments, which was proposed for the Mars '98 missions, uses XRF
primarily as a mineralogical tool. It analyzes powder samples in a transmitted,
forward reflection geometry either as-received (wind-blown) or by grinding or
drilling operations. This instrument yields bulk composition and X-ray
diffraction data simultaneously.
INSTRUMENT REQUIRED: XRF
instrument. Mass = 800 g, Power needed =
3
W
Size = 11 x 11x X-ray source:
Copper anode X-ray tube
SCANNING ELECTRON MICROSCOPE
A scanning electron microscope with chemical analytical
capability using energy dispersive analysis (SEM/EDX) could be useful in
mineralogy as a source of morphological and compositional data on individual
mineral grains.
RAMAN SPECTROSCOPY
This is an optical scattering technique, which can
provide molecular and
crystal-structural
information about solid materials. Raman spectroscopy is an established
laboratory method for identification and characterization of
organic/hydrocarbon and inorganic/mineral substances. The spectral frequency
shifts of Raman scattering are related to molecular structures in the same way
as the absorption/emission transitions in infrared absorption, reflectance, and
emission spectroscopy. Many of the problems in interpreting infrared spectra
(ex. size effects, transparency peaks, volume scattering) are not problems in
Raman Spectroscopy. Also Raman spectra can readily distinguish crystalline and
glassy materials. Some downfalls of this technique are that long analysis
times are required, high-power light sources, and a large power flux is required.
Also once a Raman spectrum is obtained, it is not clear how well spectra of
mineral mixtures can be deconvolved to yield species or the abundance of the
constituent minerals; and what the minimum detectable mineral abundance is. The
answer could lie in the technique of microscopic Raman spectroscopy on single
mineral grains (a standard laboratory technique).
INSTRUMENTS NEEDED: a
microscopic Raman spectroscopy instrument
OPTICAL LUMINESCENCE SPECTROSCOPY
Optical luminescence is emission of non-thermal optical
photons as a response to energy input. Fluorescence is prompt emission in
response to high-energy photons, and can be useful in determinative mineralogy,
especially of ionic salts (carbonates, sulfates). Fluorescence can arise from
essential elements (or ions), trace element substituents (activators), or
defects. Optical luminescence may be useful for surface investigation on Mars,
as atmosphere surface interactions may have produced ionic salts of the alkali
and alkaline earth elements. Many common minerals that do not luminesce at
visible wavelengths may do so in the infrared. Nonetheless there are some
limitations, such as it cannot provide mineral proportions or compositions, and
there has been little systematic investigation of luminescence at infrared
wavelengths or faint luminescences.
INSTRUMENTS NEEDED: a
vis-NIR spectrometer, short-wavelength
light
source
THERMAL ANALYSES
Many minerals transform or react during heating, and the
thermal effects of those transformations can be characteristic of particular
minerals. There are two standard methods, the differential thermal analysis
(DTA) and differential scanning calorimetry (DSC). In both of these methods the
unknown sample is introduced into a heating chamber in close proximity to a
reference sample and they are heated. In DTA, the sample and reference are
heated at a constant rate and in DSC sample and unknown are heated separately
so that both stay at the same temperature. Currently, DSC is limited to thermal
effects below 700oC and DTA is limited to temperatures below 1200oC. By itself
thermal analysis can detect the heat effects associated with crystalline phase
changes, magnetic order/disorder transition, chemical reactions, and melting.
Coupling thermal analysis techniques with the method of analyzing gasses
evolved during heating are especially helpful. Such gas analyzing techniques
could be by the mass spectrometer and by gas chromatography. This combination
of methods can provide info about the mixtures and complex soil samples in the
unknown sample. Thermal/evolved-gas methods are particularly powerful for
volatile-rich materials. Also it becomes easier to distinguish among clays,
silicates, feldspars, zeolites, glasses, and evaporites.
NEEDED INSTRUMENTS: a thermal
analysis instrument (don't know if
any
are flight qualified) Ex. Gooding et al
instrument
(TAPS)---has DSCs with evolved gas analysis by compound-specific
sensors. Mass = 1 kg, Energy = 5 W-hr per analysis of a 20-50 mg sample
MAGNETIZATION
A result from the Viking missions was the discovery that
the Martian soil is highly magnetic because the soil was attracted by a small
permanent magnet. Magnets brought up to Mars for future missions should be of
lower strengths than the weakest Viking magnets. The magnets should be
completely immersed in a thin magnesium plate. The magnets would be of equal
strength, but mounted at different depths below the surface of the magnesium
plate. Discrete (single phase) particles of the strongly magnetic minerals will
stick to the weaker magnets, while composite (multiphase) particles will stick
only to the strongest magnets. The Magnet Array may be able to perform X-ray
fluorescence and Mössbauer analysis of the dust on the magnets.
NEEDED INSTRUMENTS: The
magnetic array could contain 5 magnets of different strenths. Mass = 70 g,
Outer Diameter of Magnets = 18 mm each
3) More experiments involving human physiology
Renal Stone Risk Assessment
Goal:
(1) To determine the effects
of exposure to microgravity on the potential for renal stone formation.
(2) To determine the effect of mission duration on the potential risk for renal
stone formation.
(3) To determine how long after flight the increased risk exists for renal
stone formation.
Approach:
The three crewmembers
collected urine voids over a 24-hour period three times during the preflight
period (L-148, L-58 and L-34), and following landing on R+0, R+6, R+10 and
R+13. Inflight urine samples were collected on Mission Day (MD) 14, MD 93 and
MD 110. Inflight, individual urine voids were collected into a urine collection
device containing 1 ml lithium chloride as a volume marker. Two 7 ml urine
aliquots were drawn into syringe tubes containing 0.05% thymol or 0.1%
thimerosal, mixed well and stored at ambient temperatures until return to Earth
for analyses. Following the return of the samples, urine volumes were
determined from the diluted lithium concentration. Twenty-four-hour urine pools
were constructed from the individual voids and samples were analyzed for
osmolality, calcium, oxalate, uric acid, citrate, sodium, sulfate, phosphorus,
magnesium, potassium and creatinine.
Pre- and postflight, the
subjects collected 24-hour urine specimens. The pooled urine was stored chilled
at approximately 4 degrees Celsius. After total volume and pH were recorded,
two 10 ml aliquots were removed for biochemical analysis. The first sample was
analyzed for creatinine, magnesium, phosphorus, potassium, sodium and uric
acid. The second 10 ml aliquot was acidified with 6M hydrochloric acid (HCl)
and analyzed for calcium, magnesium, citrate, oxalate and sulfate. All samples
were processed immediately or stored at -20 degrees Celsius until analysis.
From the measurements, the
relative urinary supersaturation of the stone forming salts were calculated and
renal stone risk was estimated. The derived parameters were urinary
supersaturation of calcium oxalate, brushite (calcium phosphate), sodium urate,
struvite (magnesium ammonium phosphate) and uric acid saturation.
Somatic Embryogenesis of
Orchardgrass in Microgravity
Goal:
The overall objective of
this research was to provide information on the influence of microgravity on
embryo initiation, differentiation and development and the ultimate reproductive
capacity of resultant plants, using an in vitro culture system in orchardgrass
(Dactylis glomerata L.) in which the target cells remain in situ. The system
was based on paired half-leaf segments, which provided a precise control and
the opportunity to use paired statistics for analyses of the data.
Approach:
Somatic embryos form
directly from mesophyll cells in cultured leaf segments and develop fully to a
germinable stage. The basal 3 cm of the youngest two leaves were split down the
midvein. Beginning at the base, these were cut transversely into six segments
approximately 3 mm square. Segments from one half-leaf were used for the flight
treatments and the corresponding sister segments served as controls. This
provided a precise control for each treated leaf segment and the opportunity to
use paired statistics for data analysis . Observations and data were collected
on quality and quantity of embryo formation, axis determination and polarity.
Embryo number was estimated using an already-developed formula and extensive
histological data. Plants were established from somatic embryos and used for
mitotic chromosome analyses. The same plants were transferred to the field and
used for meiotic chromosome analyses and estimation of pollen fertility.
Hardware:
Biological Research In
Canisters (BRIC-100)
Developmental and
Physiological Processes Influencing Seed Production in Microgravity
Goal:
The investigator
hypothesized that a plant may become limited in gas exchange due to the lack of
convective air movement in microgravity. Since plants depend on convective air
movement to aid the uptake of metabolically important gases, the lack of
convection may affect these processes. Since the CHROMEX-03 plants were
carbohydrate-poor, carbon dioxide transport to the plants may have been
limited.
Approach:
Two Plant Growth Chambers
(PGC) were used in the Plant Growth Unit, positions 3 and 4. Each chamber held
6 mouse-ear cress (Arabidopsis thaliana) plants, which were 14 days old at
launch. The foam/agar plug nutrient system was used. A Warburg solution was
added to the chamber to maintain carbon dioxide levels. The plants were flown
for 10 days, and then recovered from the Shuttle for analysis. Measurements of
pollen viability were made immediately after landing, and material was fixed
for subsequent microscopy.
Hardware:
Plant Growth Mediums
Plant Growth Unit (PGU)
Changes in Total Body Water
During Spaceflight
Goal:
Measure the changes in total
body water (TBW) occurring in humans as a consequence of exposure to
microgravity.
Approach:
TBW was measured by the
isotope dilution technique using a dose of approximately 6 g of
[18]oxygen-labeled water (H[2][18]O) as the tracer. After ingestion of the
tracer, saliva samples were collected on dental cotton rolls over a period of
several hours. Inflight and postflight data were compared to preflight (baseline)
data. Body mass was measured before and after flight, to enable calculation of
the TBW to total body mass ratio. Data were analyzed according to the general
mixed model analysis of variance.
Hardware:
Drink Container
Saliva Collection Kit
Tracer Kit
Gravity and Skeletal Growth:
III. Recovery of Osteogenic Potential
Goal:
Data from previous space
flight missions suggest an initial inhibition of osteoblast histogenesis
followed by a postflight recovery response. This study of rat maxillary molar
periodontal ligament (PDL) allowed further investigation of the osteoblast
histogenesis recovery pattern.
Approach:
Samples were demineralized,
embedded in plastic, sectioned (4 µm) in the mid-sagittal plane of the medial
root of the first molar, and stained with hematoxylin and eosin. An ocular
micrometer was used to measure the major and minor nuclear dimensions of 100
cells in each PDL under oil immersion at 1,000x. Nuclear volume for each cell
sampled was calculated according to the formula for a prolate spheroid. The
fractional distribution of each cell type was expressed as group mean ±SEM. PDL
width was also measured at three levels within the mid-root region of the
medial root of the first molar.
4) More hardware requirements
|
A series of soil samples
from different depths below the surface will be, hardness test coupons, soft
metals, "sticky" surfaces (polymer or textured), wear test coupons
(e.g., visor material the adhesive and abrasive properties of the dust and
soil on relevant materials. |
|
Components of the
IIT IPRO Microscopy Station The Sample Delivery
System consists of a rotary/linear drive and a sample wheel. It will
present to the microscopes a series of dust samples on a variety of
substrates. It will also position the substrates relative to a fixed
multipurpose blade for removing excess material, and an abrasion tool for
abrading selected substrates. The configuration of the system has been chosen
to minimize the number of mechanisms required while still allowing soil and
dust with the greatest range of properties to be successfully imaged. The Sample Delivery System is from Surface/Interface, Inc The Optical Microscope
consists of an illumination system of superbright LEDs, an optical system,
and a black-and-white CCD camera. Illumination will be provided in four
colors (red, green, blue, and ultraviolet). The Atomic Force
Microscope is an outgrowth of the scanning tunneling microscope. The AFM
measures atomic-scale forces between a surface and a probe tip by deflection
of a microcantilever. The AFM produces topographic images of the surface with
sub-angstrom resolution. MECA's AFM incorporates a miniature low-voltage
electromagnetic drive element, piezoresistive sense elements, an array of
scan probes, and autoimaging control software. The entire AFM head has been
designed for mounting between the optical microscope objective lens and the
sample with minimal compromise of optical imaging performance. |
