Lecture 13 - Mars

what is a flyby

a movement of spacecraft passing in the vicinity of the planet but not entertaining into orbit or landing on it

when and what was the first successful attempt to go to mars

1964 the Mariner 4 (USA)

when was the first major mission to mars

NASA’s Viking project consiting of two identical orbital/lander spacecrafts with on broad a range of experiments to build up evidence for past and present life

when and what were the name of the successful mars missions and flybys

• 1975 - Vicking

• 1996 Mars global surveyor

• 1996 - mars parthfinder

• 2003 - mars exploration rover

• 2005 - mars reconnassance orbiter

• 2011 - mars science laboratory

what year did the viking landers touch down on mars

1976

what experiments did the viking spaceships complete

• pyrolytic relearse experiment

• gas exchange experiment

• labled release experiment

to detect possibly metabolic activity of potential microbial soil communities

what is the viking labeled release experiment

designed to detect ccarbon dioxide released by microorganisms as a result of their metabolic activity

• the LR experiment worked by scooping up a bit of martian soil and mixing it with a broth of 7 organic nutrients labeled with radioactive C-14 atoms

• if the soil contained microbes then the life-forms would metabolize the nutrients and release either radioactive CO2 or methand gas which could be measured by a radiation detector on the probe

did the labled release experiment show signs of life

• when the nutrients were mixed with the soil sample it resulted in 10,000 counts of radioactive molecules a huge spike from the 50 or 60 counts that consituted the natural background radiation on mars

what was the gas chromatograph experiment

device on board of landers to detect small concentrations of organic compounds in samples of soil on mars

• GC-MS chemically separates vapour compounds via a gas chromatopgraph and then feeding the result into a mass spectrometer wich measures the molecular weight of each chemical

how is the GC-MS used?

to analyse components of untreated matrian soil. particularly those components released as the soil is heated to different temperatures

what did the GC-MS experiment show (result)

• Fe, Si and O were found but no carbon - no organic matter on martian surface

• result was difficult to explain if martian bacterial metabolism was reponsible for the positive results seen by LR exp

what is the validity under question for the GC-MS

GC-MS probably incapable of detecting small concentrations of organic material even if these were present.

what is the genrally accepted results of the viking experiments

caused by chemical and not biological

what details were discovered

• no ozone in atmosphere therefore intense UV bombardment of the surface

• UV radiation sterilises the soil and also disrupts any
  organic molecules

• It is also thought there is a strong oxidising agent in
  the soil (hydrogen peroxide) which would also attack
  any organic molecules.

what is the mars global surveyor

• NASA's spacecraft into orbit around Mars

• Since March 1999, MGS is returning (more than 240,000) images and detailed maps, showing

what hemispheres does the MGS show

• south - quite rough and heavily cratered, indicating an old surface

• north - low, level plain, a younger surface with few craters

what is the mars parthfinder

• landed in 1997 consited of a lander and a wheeled robotic mars rover named sojourner

• Sojourner (designed for a mission lasting 7 sols*)
  explored Mars for around three months (83 sols).

• The rover needed the base station to communicate with Earth.

how far did the sojourner travell on mars

just over 100 metres

what did the results show from sojourner

• an X ray was used to determine the composition - found all eliments but hydrogen

• positional measurements of lander on surface showed rotation axis of mars to be processing

what did measurements from the viking landers combined with doppler shifts show

mars may have a solid iron core between 1300km and 2400km in radius

what is precession rate controlled by

distrubution of mass within

what does the precession rate show

indicate a hot, active interior early in mar's’ history

what did the pathfinder show regarding the weather on mars

• the martian surface temperature is usually well below freezing, while the atmospheric pressure is less than 1% of earth’s

• mars axis tilt is very similar to earth and has seasons. however a mars year is almost twice as long, and orbit is more exxentric than earths causing martian seasons to be different than ours

what are mars seasons

• sourthern hemisphere has more extreme seasons (shorter and warmer summers and longer and colder winters) than its northern hemisphere

• season changes lead to major features on martian weather

• the temp in winter drops so low that co2 condenses into dry ice at the polar cap but in the summer carbon dioxide ice sublimates and water ice remains

• the atmospheric pressure increases at summer pole and decreases at winter pole

what did the pathfinder show unususal weathre

• strong winds associated with the cycling of carbon dioxide gas can initiate huge dust storms

• the martian winds can also spawn dust devils: swirling winds that loo like miniature tornadoes

what did the mars exploration rover mission: spirit and opportunity do

• landed in 2004 and explored the martian surface and geology

• travelled 45 km

• ended contact in 2018

what did opportinity find

‘blueberries’ were found. their composition were analysed with spectrometers: concentrations formed by minerals coming out of solution a water diffused through rock

are there clouds on mars

yes. martian atmosphere these clouds consist of either co2 or water-based ice crystals

is there water on mars

• yes excusively water on mars exists today almost only as ice with a small amount present in the atmosphere as vapour

what is the history of water on mars

• 4600 myr - meteoritic bombardment makes evolution of life unlikely

• 4200 myr - a warm wet atmosphere allows liquid water, and life could star to evolve

• 3800 myr - co2 gradually disappears from atmosphere causing rivers and lakes to freeze

• 3100 myr - atmosphere thins - no liwuid water can remain on surface

• 1500 myr - atmsophere very thin - no liquid water

how does reull vallis hsow evidene of liwuid water

• valleys on mars carved by water

• on the floors of some channels are features called lineated floor deposits that are ridged and grooved materals that seem to deflect around obsticles. they are believed to be ice-rich

• some galciers on the earth show such features

what is a major evidence of liwuid water

• Images taken several years apart revealed some changes in the most recent pictures, highlighting what looked like outflow channels from surges of liquid water
  

• However, scientists at the University of Arizona made simulations showing that the shapes and characteristics of the observed gullies most resembled that of the modelled gullies shaped by dry debris tumbling down a slope.

what did NASA’s 2001 odyssey try and look for water

• Mission: to use spectrometers and
  thermal imager to detect evidence of
  past or present water and ice, as well
  as study the planet's geology and
  radiation environment.

• The gamma-ray spectrometer
  instrument on board was used to
  detect hydrogen

what did the 2001 odyssey find on mars

found the presence of water ice in the upper 1m of soil in a large region surrounding the planet’s south pole it could not see any deeper than 1m

what did the results of the mars odyssey show

The amount ofnhydrogen detected by the gamma-ray spectrometer indicates 20 to 50 percent ice by mass in the
lower layer.

what did the Mars Reconnaissance Orbiter (MRO) show

• Darkish streaks appear to ebb and flow over time: they darken and appear
  to flow down steep slopes during warm seasons, and fade in cooler seasons.

gives evidence of salty water

what was the overall objectives of mars ecience laboratory and curiosity (MSL)

investigating Mars' habitability, studying its climate and geology, and collecting data for a manned mission to Mars

what is the perseverance

NASA’s Mars 2020
rover landed in Feb 2021, taking
photos of rocks and searching for
signs of past and present life on
the surface

when is the ExoMars

Two- part ESA/Roscosmos project to search for evidence of life on Mars:

• Trace Gas Orbiter (launched in 2016) + Schiaparelli lander (crashed)

• Rosalind Franklin rover will be launched in 2028, to take samples of the Martian soil up to 2m deep to search for spores of life