IA Chapter 3 Mars Flashcards
What reaction series occurs to maintain CO2 levels in the Martian atmosphere?
H + O2 > HO2 + M
O + HO2 > O2 + OH
CO + OH > CO2 +H
Where M is a catalyst.
Can mars support life?
It is not believed that mars’ surface could support microbial life, however there is still potential in rocks and underground.
Why did the Viking experiments return positive results for life in the control test?
Because non biological processes were operating that undermined the experiments’ validity.
The high UV experienced on mars’ surface can generated peroxides this reaction could be catalysed by iron.
How were ancient hat spring like environments found on earth and why is it significant?
Curiosity rover discovered rich silica deposits which are suggested to have formed due to the altercation of the Martian soil by contact with acidic steam from volcanic activity or adjacent to a hot spring.
Hot Springs provide niche environments that are habitable by extreme files they are warm and nutrient rich.
Have carbonate been discovered on Mars?
Both magnesium and iron carbonate has been found, interpreted as precipitated from carbonate bearing solutions under the hydrothermal conditions near neutral pH in association with volcanic activity have been found.
What evidence do we have for water on Mars?
-Conglomerates
-Mudstone
-Sedimentary structures
These are evidence of previous fluid activity.
What are the six lines of evidence for water presently on Mars?
- ground penetrating radar
-Gammaray and neutron spectrometry
-New impact craters
-Landforms
-Active gullies
-Recurring slope lineae
What is a ground penetrating radar?
A technique that uses downward pointing radar to detect the echoes from a sub surface water table or from surface layers of ice.
What is gamma and neutron spectroscopy?
These map the abundance of hydrogen in the top most meter of the Martian soil.
as the most abundant source of hydrogen is water, this is a useful way of mapping water.
In the upper meter of Martian soil there is the equivalent of a 14 cm layer of ice. This could be deeper as the survey only goes to 1 meter.
How does gamma ray and neutron spectroscopy work?
Cosmic rays collide with the nuclei of atoms on the surface of Mars and energise them. when the nuclei return to their original energy level, they emit a gamma ray photon. different elements emit different energy gamma ray photons allowing you to identify the elements present.
What are landforms?
These are various characteristic features that may be seen on the surface of planets indicating ice.
Examples are
- patterned ground
- broad valleys feeding debris aprons
What are active gullies?
‘these are channels approximately 1 km long by 10 km wide. They are still active today and could be formed by swimming pool volumes of water being entombed underground until suddenly an ice plug bursts letting the water rush down the slope.
The water may remain a liquid for a longer time if it forms an ice skin on the surface or has a high concentration of salt dissolved in it lowering its freezing point.
They may also be formed by dry processes such as avalanches and rock fall.
What are recurring slope lineae?
These are a downslope feature with no erosion. They are ephemeral dark narrow streaks that occur in 1 clusters of 10 or even hundreds and become visible during the warmest seasons.
What are SNC meteorites?
These are igneous rocks formed by the crystalization of magma. They typocally have relatively young ages of 0.2-1.3 Ga which means they formed more recently then typical meteorites. This suggests they likely formed on another planetary body.
How do we know SNC meteorites are from Mars?
When an impact occurs small pockets of shock-induced melt happen in the rock. This forms glass which traps pockets of atmosphere in solution. When analysing these samples the abundant concentrations of gasses match that reported by landers on Mars.
What is impact erosion?
Hot gas plumes expanding from major impacts faster than the escape velocity could remove up to 99% of the gas from Mars’s atmosphere.
What is hydrodynamic escape?
This is when a rapidly moving stream of gas is lost from an atmosphere to space due to thermal escape. Lighter particles are more likely to be lost this way but can carry heavier molecules in their flows.
What processes caused Mars’s atmosphere to deplete?
- Hydrodynamic escape
- Impact erosion
- Sputtering/Solar wind stripping
Why may the presence of methane on Mars suggest life?
Methane in Mars’s atmosphere should be rapidly oxidised, meaning that the methane must have been produced recently. Methane can be explained non-organically, however, the planet is no longer believed to be volcanically active ruling out that and hydrothermal activity.
Planetary protection: Category 1
Any mission to a target body that is not of direct interest for
understanding the process of chemical evolution or the origin of life. No protection of
such bodies is warranted and no planetary protection requirements are imposed.
Planetary protection: Category 2
All types of missions to those target bodies where there is significant
interest in the process of chemical evolution and the origin of life, but where there
is only a remote chance that contamination carried by a spacecraft could jeopardize
future exploration. The concern is primarily over unintentional impact, since these
missions are not designed to land.
Planetary protection: Category 3
Missions (mostly y-by and orbiter) to a target body of interest for
studying chemical evolution and/or origin of life, or for which scientific opinion
provides a significant chance of contamination that could jeopardize a future
biological experiment.
Planetary protection: Category 4
Missions (mostly probe and lander) to a target body of interest for
studying chemical evolution and/or origin of life, or for which scientific opinion
provides a significant chance of contamination that could jeopardize a future
biological experiment.
Planetary protection: Category 5
All Earth-return missions. The concern is the protection of the terrestrial system, the Earth and the Moon. In the subcategory defined as restricted Earth return, there is an absolute prohibition of destructive impact upon return, and a requirement for containment throughout the return phase of all returned hardware
that directly contacted the target body or unsterilized material from the body, and
for containment of any unsterilized sample collected and returned to Earth. For
Solar System bodies deemed by scientific opinion to have no Indigenous life forms,
a subcategory unrestricted Earth return is dened, for which planetary protection
requirements apply on the outbound phase only
