Icebreaker Life
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''Icebreaker Life'' is a
Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...
lander mission concept proposed to NASA's Discovery Program. The mission involves a stationary lander that would be a near copy of the successful 2008 ''Phoenix'' and
InSight Insight is the understanding of a specific cause and effect within a particular context. The term insight can have several related meanings: *a piece of information *the act or result of understanding the inner nature of things or of seeing intu ...
spacecraft, but would carry an
astrobiology Astrobiology, and the related field of exobiology, is an interdisciplinary scientific field that studies the origins, early evolution, distribution, and future of life in the universe. Astrobiology is the multidisciplinary field that investig ...
scientific payload, including a drill to sample ice-cemented ground in the northern plains to conduct a search for
biosignature A biosignature (sometimes called chemical fossil or molecular fossil) is any substance – such as an element, isotope, or molecule – or phenomenon that provides scientific evidence of past or present life. Measurable attribute ...
s of current or past
life on Mars The possibility of life on Mars is a subject of interest in astrobiology due to the planet's proximity and similarities to Earth. To date, no proof of past or present life has been found on Mars. Cumulative evidence suggests that during the ...
. The science goals for ''Icebreaker Life'' focus on sampling ice-cemented ground for its potential to preserve and protect
biomolecules A biomolecule or biological molecule is a loosely used term for molecules present in organisms that are essential to one or more typically biological processes, such as cell division, morphogenesis, or development. Biomolecules include large ...
or
biosignature A biosignature (sometimes called chemical fossil or molecular fossil) is any substance – such as an element, isotope, or molecule – or phenomenon that provides scientific evidence of past or present life. Measurable attribute ...
s. ''Icebreaker Life'' was not selected during the 2015 or 2019 Discovery Program competitions.


Mission profile

The ''Icebreaker Life'' mission has been designed based on the successful 2008 ''Phoenix'' lander in terms of platform and northern landing site. The ''Icebreaker Life'' will also be
solar-powered Solar power is the conversion of energy from sunlight into electricity, either directly using photovoltaics (PV) or indirectly using concentrated solar power. Photovoltaic cells convert light into an electric current using the photovoltaic ef ...
and will be able to accommodate the drill and the rest of the payload with only minor modifications to the original lander. Had it been selected for the Discovery program mission 13, the lander would have been launched no later than December 2021. The lander would arrive over the northern plains of
Mars Mars is the fourth planet from the Sun and the second-smallest planet in the Solar System, only being larger than Mercury (planet), Mercury. In the English language, Mars is named for the Mars (mythology), Roman god of war. Mars is a terr ...
in 2022. Operations on the surface would last for 90 sols. Command, control, and data relay are all patterned after the ''Phoenix'' mission with relay to Mars orbiters and direct to Earth as a backup.
Christopher McKay Dr Christopher P. McKay (born 1954) is an American planetary scientist at NASA Ames Research Center, studying planetary atmospheres, astrobiology, and terraforming. McKay majored in physics at Florida Atlantic University, where he also studied m ...
is the Principal Investigator. In 2010, the ''Icebreaker'' science payload was proposed as the baseline science payload for developing a joint NASA-SpaceX now-canceled mission that was called ''Red Dragon''.


Objectives

The Mars ''Icebreaker Life'' mission focuses on the following science goals: # Search for specific biomolecules that would be conclusive evidence of life. # Perform a general search for
organic molecules In chemistry, organic compounds are generally any chemical compounds that contain carbon-hydrogen or carbon-carbon bonds. Due to carbon's ability to catenate (form chains with other carbon atoms), millions of organic compounds are known. The s ...
in the ground ice. # Determine the processes of ground ice formation and the role of
liquid water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a s ...
. # Understand the mechanical properties of the Martian polar ice-cemented soil. # Assess the recent habitability (5 million years ago) of the environment with respect to required elements to support life, energy sources, and possible toxic elements. # Compare the elemental composition of the northern plains with mid-latitude sites. To further the current understanding of the habitability of the ice in the northern plains and to conduct a direct search for organics, the Mars ''Icebreaker Life'' mission focuses on the following science goals: # Search for specific biomolecules that would be conclusive evidence of past life. Biomolecules may be present because the ''Phoenix'' landing site is likely to have been habitable in recent Martian history. Ground ice may protect organic molecules on Mars from destruction by oxidants and radiation, and as a result organics from biological or meteorite sources may be detectable in polar ice-rich ground at significant concentrations. # Perform a general search for organic molecules in the ground ice. If habitable conditions were present, then any organics may be of recent (<10 million years) biological origin. # Determine the nature of the ground ice formation and the role of
liquid water Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a s ...
. There may have been liquid water generated in the surface soils in the north polar regions within the past <10  million years due to orbital changes in
insolation Solar irradiance is the power per unit area (surface power density) received from the Sun in the form of electromagnetic radiation in the wavelength range of the measuring instrument. Solar irradiance is measured in watts per square metre (W/m ...
. # Understand the mechanical properties of the martian polar ice-cemented soil. Polar ice may be a resource for human exploration, and the mechanical properties will reflect the stratigraphy of ice and soil, which may inform models of climate history. # Assess the recent habitability of the environment with respect to required elements to support life, energy sources, and possible toxic elements. The perchlorate present at the Phoenix site could provide a usable energy source if ferrous iron is present. A source of fixed nitrogen, such as
nitrate Nitrate is a polyatomic ion A polyatomic ion, also known as a molecular ion, is a covalent bonded set of two or more atoms, or of a metal complex, that can be considered to behave as a single unit and that has a net charge that is not zer ...
, is required for habitability. # Compare the elemental composition of the northern plains with mid-latitude sites. Duplicate samples could be cached as a target for possible return by a Mars sample return mission. If the samples were shown to contain organic
biosignatures A biosignature (sometimes called chemical fossil or molecular fossil) is any substance – such as an element, isotope, or molecule – or phenomenon that provides scientific evidence of past or present life. Measurable attribute ...
, interest in returning them to Earth would be high.


Science

The results from previous missions, and the ''Phoenix'' mission in particular, indicate that the ice-cemented ground in the north polar plains is likely to be the most recently habitable place that is currently known on Mars. The near-surface ice likely provided adequate
water activity Water activity (''aw'') is the partial vapor pressure of water in a solution divided by the standard state partial vapor pressure of water. In the field of food science, the standard state is most often defined as pure water at the same tempera ...
(aw) during periods of high obliquity 5 million years ago, when Mars had an orbital tilt of 45°, compared to the present value of 25° and ground ice may have melted enough to preserve organic molecules, including organic
biosignature A biosignature (sometimes called chemical fossil or molecular fossil) is any substance – such as an element, isotope, or molecule – or phenomenon that provides scientific evidence of past or present life. Measurable attribute ...
s. The two ''Viking'' landers conducted in 1976 the first, and so far only, search for current life on Mars. The biology experiments sought to detect living organisms based on the hypothesis that microbial life would be widely present in the soils, as it is on Earth, and that it would respond to nutrients added with liquid water. The ''Viking'' biology experiments operated successfully on both landers, with an instrument showing signs of active bacterial
metabolism Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cell ...
, but it did not occur with a duplicate heat-treated sample. Other instruments yielded negative results with respect to the presence of organic compounds. The results of the ''Viking'' mission concerning life are considered by the general expert community, at best, as inconclusive. Scientists deducted that the ambiguous results may have been caused by an oxidant in the soil. The organic analysis instrument on ''Phoenix'' ( TEGA) was also defeated by the presence an oxidant in the soil, but this lander was able to identify it:
perchlorate A perchlorate is a chemical compound containing the perchlorate ion, . The majority of perchlorates are commercially produced salts. They are mainly used as oxidizers for pyrotechnic devices and to control static electricity in food packaging. Per ...
. The SAM instrument (
Sample Analysis at Mars Sample Analysis at Mars (SAM) is a suite of instruments on the Mars Science Laboratory Curiosity (rover), ''Curiosity'' rover. The SAM instrument suite will analyze Organic compound, organics and gases from both atmospheric and solid samples. It ...
) currently in use on board the Mars Science Laboratory's ''Curiosity'' rover, has three capabilities that should allow it to detect organics despite interference from perchlorate. A null result would establish that Earth-like life is likely not present in the ground ice, arguably the most habitable environment currently known on Mars, implying that Earth-like life is absent on Mars generally. This would lower the risk for biohazards during human exploration or sample return. However, this would not rule out life that does not have Earth-like biomarkers.


Preservation of biomolecules

One of the key goals of the ''Icebreaker Life'' mission is to test the
hypothesis A hypothesis (plural hypotheses) is a proposed explanation for a phenomenon. For a hypothesis to be a scientific hypothesis, the scientific method requires that one can test it. Scientists generally base scientific hypotheses on previous obse ...
that the ice-rich ground in the polar regions has significant concentrations of organics due to protection by the ice from
oxidants An oxidizing agent (also known as an oxidant, oxidizer, electron recipient, or electron acceptor) is a substance in a redox chemical reaction that gains or " accepts"/"receives" an electron from a (called the , , or ). In other words, an oxi ...
and
radiation In physics, radiation is the emission or transmission of energy in the form of waves or particles through space or through a material medium. This includes: * ''electromagnetic radiation'', such as radio waves, microwaves, infrared, visi ...
. Non-biological organics from infalling meteorites could be detectable in polar ice-rich ground at significant concentrations, so they could be used as indicators that ice actually protect and preserve organic molecules, whether biological or not. If non-biological organics are found, then the north polar regions would be compelling targets for future
astrobiology Astrobiology, and the related field of exobiology, is an interdisciplinary scientific field that studies the origins, early evolution, distribution, and future of life in the universe. Astrobiology is the multidisciplinary field that investig ...
missions, especially because of the potential recent habitability (5 million years ago) of this ice. Target
biomolecule A biomolecule or biological molecule is a loosely used term for molecules present in organisms that are essential to one or more typically biological processes, such as cell division, morphogenesis, or development. Biomolecules include large ...
s will be
aminoacid Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...
s,
protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
s,
polysaccharide Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with wa ...
s,
nucleic acids Nucleic acids are biopolymers, macromolecules, essential to all known forms of life. They are composed of nucleotides, which are the monomers made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main clas ...
(''e.g''., DNA,
RNA Ribonucleic acid (RNA) is a polymeric molecule essential in various biological roles in coding, decoding, regulation and expression of genes. RNA and deoxyribonucleic acid ( DNA) are nucleic acids. Along with lipids, proteins, and carbohydra ...
) and some of their derivatives, NAD+ involved in
redox Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate (chemistry), substrate change. Oxidation is the loss of Electron, electrons or an increase in the oxidation state, while reduction ...
reactions,
cAMP Camp may refer to: Outdoor accommodation and recreation * Campsite or campground, a recreational outdoor sleeping and eating site * a temporary settlement for nomads * Camp, a term used in New England, Northern Ontario and New Brunswick to descri ...
for intracellular signals, and polymeric compounds such as
humic acid Humic substances (HS) are organic compounds that are important components of humus, the major organic fraction of soil, peat, and coal (and also a constituent of many upland streams, dystrophic lakes, and ocean water). For a long era in the 19th ...
s and
polyglutamic acid Polyglutamic acid (PGA) is a polymer of the amino acid glutamic acid (GA). Gamma PGA (Poly-γ-glutamic acid, γ-PGA) - the form where the peptide bonds are between the amino group of GA and the carboxyl group at the end of the GA side chain - i ...
—formed by bacterial
fermentation Fermentation is a metabolic process that produces chemical changes in organic substrates through the action of enzymes. In biochemistry, it is narrowly defined as the extraction of energy from carbohydrates in the absence of oxygen. In food ...
. ;Ionizing radiation
Ionizing radiation Ionizing radiation (or ionising radiation), including nuclear radiation, consists of subatomic particles or electromagnetic waves that have sufficient energy to ionize atoms or molecules by detaching electrons from them. Some particles can travel ...
and
photochemical Photochemistry is the branch of chemistry concerned with the chemical effects of light. Generally, this term is used to describe a chemical reaction caused by absorption of ultraviolet (wavelength from 100 to 400  nm), visible light (400–7 ...
oxidants are more damaging in dry regolith, therefore, it may be necessary to reach ~ deep where organic molecules may be shielded by the ice from the surface conditions. The optimal deposition rate for the landing site would be such that of drill will sample through 6 million years of sediment. ;Perchlorate
Perchlorate A perchlorate is a chemical compound containing the perchlorate ion, . The majority of perchlorates are commercially produced salts. They are mainly used as oxidizers for pyrotechnic devices and to control static electricity in food packaging. Per ...
is the most oxidized form of the element
chlorine Chlorine is a chemical element with the Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate betwee ...
, but it is not reactive at ambient conditions on Mars. However, if heated to above 350 °C perchlorate decomposes and releases reactive chlorine and oxygen. Thus, the ''Viking'' and ''Phoenix'' thermal processing of the soils would have destroyed the very organics they were attempting to detect; thus the lack of detection of organics by ''Viking'', and the detection of chlorinated organic species, may reflect the presence of perchlorates rather than the absence of organics. Of particular relevance, some microorganisms on Earth grow by the anaerobic reductive dissimilation of perchlorate and one of the specific enzymes used,
perchlorate reductase Perchlorate reductase is an enzyme that catalyzes the chemical reactions: :ClO4− + 2 AH2 \rightleftharpoons ClO2− + 2 A + 2 H2O and :ClO3− + AH2 \rightleftharpoons ClO2− + A + H2O Thus, the substrates of this enzyme are a reduced el ...
, is present in all known examples of these microorganisms. Also, perchlorates are toxic to humans, so understanding the chemistry and distribution of perchlorate on Mars might become an important prerequisite before the first
human mission to Mars The idea of sending humans to Mars has been the subject of aerospace engineering and scientific studies since the late 1940s as part of the broader exploration of Mars. Some have also considered exploring the Martian moons of Phobos and Deimos. ...
.


Habitability

While
sunlight Sunlight is a portion of the electromagnetic radiation given off by the Sun, in particular infrared, visible, and ultraviolet light. On Earth, sunlight is scattered and filtered through Earth's atmosphere, and is obvious as daylight when t ...
is a powerful energy source for life, it is unlikely to be biologically useful on present Mars because it requires life to be at the surface exposed to the extremely lethal radiation and to dry conditions. The team estimates that if ice-cemented ground at the landing site was in fact raised 5 million years ago to temperatures warmer than −20 °C, then the resultant
water activity Water activity (''aw'') is the partial vapor pressure of water in a solution divided by the standard state partial vapor pressure of water. In the field of food science, the standard state is most often defined as pure water at the same tempera ...
(aw=0.82) may have allowed for microbial activity in the thin films of unfrozen water that form on the protected boundary beneath the soil and ice for temperatures above −20 °C. ''Icebreaker Life'' would study the concentration and distribution of
ferrous iron In chemistry, iron(II) refers to the element iron in its +2 oxidation state. In ionic compounds (salts), such an atom may occur as a separate cation (positive ion) denoted by Fe2+. The adjective ferrous or the prefix ferro- is often used to spe ...
,
nitrate Nitrate is a polyatomic ion A polyatomic ion, also known as a molecular ion, is a covalent bonded set of two or more atoms, or of a metal complex, that can be considered to behave as a single unit and that has a net charge that is not zer ...
, and
perchlorate A perchlorate is a chemical compound containing the perchlorate ion, . The majority of perchlorates are commercially produced salts. They are mainly used as oxidizers for pyrotechnic devices and to control static electricity in food packaging. Per ...
as a biologically useful
redox Redox (reduction–oxidation, , ) is a type of chemical reaction in which the oxidation states of substrate (chemistry), substrate change. Oxidation is the loss of Electron, electrons or an increase in the oxidation state, while reduction ...
couple -or energy source- in the ground ice. McKay argues that subsurface
chemoautotrophy A Chemotroph is an organism that obtains energy by the oxidation of electron donors in their environments. These molecules can be organic ( chemoorganotrophs) or inorganic (chemolithotrophs). The chemotroph designation is in contrast to phototrop ...
is a valid energy alternative for Martian life. He suggests that perchlorate and nitrate could form the oxidizing partner in a redox couple if suitable reduced material were available. ;Nitrogen fixation After carbon,
nitrogen Nitrogen is the chemical element with the symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at se ...
is arguably the most important element needed for life. Thus, measurements of
nitrate Nitrate is a polyatomic ion A polyatomic ion, also known as a molecular ion, is a covalent bonded set of two or more atoms, or of a metal complex, that can be considered to behave as a single unit and that has a net charge that is not zer ...
over the range of 0.1% to 5% are required to address the question of its occurrence and distribution. There is nitrogen (as N2) in the atmosphere at low levels, but this is not adequate to support
nitrogen fixation Nitrogen fixation is a chemical process by which molecular nitrogen (), with a strong triple covalent bond, in the air is converted into ammonia () or related nitrogenous compounds, typically in soil or aquatic systems but also in industry. Atmo ...
for biological incorporation. Nitrogen in the form of
nitrate Nitrate is a polyatomic ion A polyatomic ion, also known as a molecular ion, is a covalent bonded set of two or more atoms, or of a metal complex, that can be considered to behave as a single unit and that has a net charge that is not zer ...
, if present, could be a resource for human exploration both as a nutrient for plant growth and for use in chemical processes. On Earth, nitrates correlate with perchlorates in desert environments, and this may also be true on Mars. Nitrate is expected to be stable on Mars and to have formed in shock and electrical processes. Currently there is no data on its availability.


Proposed payload

''Icebreaker Life'' would carry a rotary-percussive drill and the proposed scientific instruments have already been tested in relevant analogue environments and on Mars. * Signs Of LIfe Detector (SOLID) instrument can detect whole cells, specific complex organic molecules, and polymers via fluorescence
immunoassay An immunoassay (IA) is a biochemical test that measures the presence or concentration of a macromolecule or a small molecule in a solution through the use of an antibody (usually) or an antigen (sometimes). The molecule detected by the immunoass ...
s. Using a single Life-Detection Chip (LDCHIP) measuring a few square centimeters, SOLID's antibody library can detect up to 300 different organic molecules. The instrument would carry 16 Life-Detection Chips. *The Wet Chemistry Laboratory (WCL) is a powerful analytical instrument that would measure the pH, Eh, conductivity, and dissolved ions present in the ice-cemented ground. The WCL was used successfully on the 2007 ''Phoenix'' lander mission. *A laser desorption mass spectrometer (LDMS) would detect and characterize a wide range of nonvolatile organic compounds. The LDMS uses a pulsed laser desorption/ionization (LDI) process, in which molecular ions are sampled directly from particulate samples at Mars ambient pressure, with no vacuum loading required. The LDMS method is not impacted by the presence of perchlorate. *Rotary-percussive drill and a selected set of instruments. The drill penetrates in ice-cemented ground and the cuttings from this drill are sampled by a robotic sample handling system, *The lander uses the ''Phoenix'' Surface Stereo Imager (SSI) for monitoring drill and sample delivery operations. It would provide important context information to estimate ice depth and also to understand any surface conditions that may affect mission operations and drill placement.


Planetary protection

The mission must comply with the
planetary protection Planetary protection is a guiding principle in the design of an interplanetary mission, aiming to prevent biological contamination of both the target celestial body and the Earth in the case of sample-return missions. Planetary protection refle ...
requirements established by
NASA The National Aeronautics and Space Administration (NASA ) is an independent agency of the US federal government responsible for the civil space program, aeronautics research, and space research. NASA was established in 1958, succeeding t ...
and the international
Committee on Space Research The Committee on Space Research (COSPAR) was established on October 3, 1958 by the International Council for Scientific Unions (ICSU). Among COSPAR's objectives are the promotion of scientific research in space on an international level, wi ...
(COSPAR).


See also

*
Astrobiology Astrobiology, and the related field of exobiology, is an interdisciplinary scientific field that studies the origins, early evolution, distribution, and future of life in the universe. Astrobiology is the multidisciplinary field that investig ...
*
Biological Oxidant and Life Detection The Biological Oxidant and Life Detection (BOLD) is a concept mission to Mars focused on searching for evidence or biosignatures of microscopic life on Mars (planet), life on Mars. The BOLD mission objective would be to quantify the amount of hydr ...
*
ExoMars ExoMars (Exobiology on Mars) is an astrobiology programme of the European Space Agency (ESA). The goals of ExoMars are to search for signs of past life on Mars, investigate how the Martian water and geochemical environment varies, investigate ...
*
Exploration of Mars The planet Mars has been explored remotely by spacecraft. Probes sent from Earth, beginning in the late 20th century, have yielded a large increase in knowledge about the Martian system, focused primarily on understanding its geology and habit ...
*
Mars 2020 Mars 2020 is a Mars rover mission forming part of NASA's Mars Exploration Program that includes the rover ''Perseverance'', the small robotic, coaxial helicopter '' Ingenuity'', and associated delivery vehicles. Mars 2020 was launched from Ear ...
*
Water on Mars Almost all water on Mars today exists as ice, though it also exists in small quantities as vapor in the atmosphere. What was thought to be low-volume liquid brines in shallow Martian soil, also called recurrent slope lineae, may be grains of f ...


References

{{DEFAULTSORT:Icebreaker Life Missions to Mars Proposed NASA space probes Discovery program proposals Proposed astrobiology space missions