Lecture 25/26: Mars

Question 1

what is the history of water on mars, and the implications for habitability?

Answer 1

during the noachian period, there was lots of water, including lake basins and possibly shallow oceans

water amount decreases in hesperian period, with sulfur-rich minerals indicating acidic water conditions, less favourable for life

formation of outflow channels from catastrophic floods

amazonian period today is a cold, dry, and largely waterless surface, with most water locked as ice at the poles

the conditions for microbial life were met in the noachian period, but with the altered environment we are limited on places to look for life- still possible in subsurface niches hosting extremophillic microbial life

Question 2

what are the major factors that influence the habitability of mars?

Answer 2

a source of liquid water
a source of energy
a source of elements (CHNOPS) and other nutrients
physical conditions suitable for life
radiation- high UV radiation about 1000 times greater in damaging DNA than on earth

Question 3

what are the geophysical and atmospheric reasons why mars lost surface liquid water?

Answer 3

loss of planetary magnetic field
- protected mars atmosphere from the solar wind
- led to rapid erosion of atmosphere, reducing pressure and making surface water unstable

greenhouse effect collapse
- early mars had a thicker CO2 rich atmosphere that kept surfaces warm through the greenhouse effect
- atmosphere thinned, greenhouse warming declined, plummeting surface temperatures

Question 4

existence of mars meteorites and how we know they come from mars

Answer 4

igneous rocks ejected from mars during large asteroid or comet impacts

we know they come from mars as the composition of gases in the meteorites matches mars

Question 5

what is some evidence for life in martian meteorites, and why is it controversial?

Answer 5

shapes that look like microbes found

mineral grains of magnetite that some bacteria make

organic compounds called PAHs

• controversial as PAHs can form abiotically during shock, volcanic, or hydrothermal processes

Question 6

what is a mars analog environment, and why might they be useful for science and exploration?

Answer 6

an environment on earth that mimics key conditions found on mars, such as climate, geology, soil chemistry etc

tests a rover for mining and planetary exploration, sniffing gas and 3D mapping before sending it to mars

environmental monitoring networks underground and on other planets to measure radiation, temperatures, pressures etc

all conditions that must be at suitable points to sustain life

Question 7

what are some of the main concepts for the human exploration of mars?

Answer 7

semi-permanent base
- long-term habitat for repeated or continuous human presence

surface habitat
- to protect from radiation, dust, and cold

mobility and exploration
- rovers for astronauts
- crew will explore areas of geological and astrobiological interest

Question 8

where would we get resources from to subsist on mars?

Answer 8

fuel for rovers, heating, and other systems could be made from methane in the sabatier reaction using something like nickel on mars

the H2 would be acquired from the electrolysis of water and CO2 extracted from atmosphere

methane could be liquified and used for a large variety of fuel-requiring processes