Mars In Order Research Articles

The Descartes Code (Spin Orbital Rotation of Photons)–IV. The Harress-Sagnac Color Excess in the Rotation Curves of Galaxies

In 1933, Zwicky formulated the significant bifurcation point in the history of astrophysics. Zwicky postulated an unknown dark matter in order to explain the color excess in the observed Doppler effect in the rotation curves of galaxies. However, until now we have not detected these dark matter particles. In this contribution, we propose to come back to this bifurcation point and to interpret the observed color excess as the Harress-Sagnac effect known in the rotating interferometers. We have described photon properties in those rotating interferometers based on the old color theory of Descartes—rotating light globules (spin-orbital rotation of photons). Therefore, the color excess observed in the rotation curves of galaxies can be interpreted as the additional color excess of photons emitting from distant rotating stars. Formulae for these color excesses are given for different locations of the rotating galaxy inspired by Zwicky’s core-shell model of galaxies. A part of Zwicky’s enigma is an unknown influence of the Solar gravitational field at 1 AU on the distant photon properties. From the forgotten Gerber’s retarded potential formula we have derived an expression for the acceleration of distant photons towards the Sun at 1 AU as ax = 1.171 × 10⁻¹⁰ ms⁻². This is a very surprising coincidence with the Milgrom empirical value a0 = (1.2 ± 0.1) × 10⁻¹⁰ ms⁻². Therefore, we propose to test this new formula at the surface of Mercury and Mars in order to reveal if our gravitational models are universal or “geocentric”, valid for the surroundings of the Earth only.

Colin Trevor Pillinger. 9 May 1943—7 May 2014

Colin Pillinger was a larger-than-life planetary scientist with an infectious enthusiasm for science. He was a founding member of the Planetary and Space Sciences Research Institute at the Open University in Milton Keynes. He was a mass spectroscopist who applied these techniques with great success to the study of extraterrestrial rock samples from both meteorites and the Moon. He helped identify a class of meteorite found on Earth that originated from Mars. In turn, this led to leadership of the Beagle 2 Mars lander project, which was designed to take scientific instruments to Mars in order to search for evidence of past life. Against all odds, the landing on Mars was successful, but communication with the lander was never established. Colin was a brilliant innovator, both in his science and in adopting a somewhat unconventional approach to funding the ambitious Beagle 2 project. He enjoyed the fact that, even though it was possible to purchase off-the-shelf instrumentation, the truly creative aspect of his analytic method was in the details of how it was applied, for which the rule book was still being written. Throughout his career he continued to ride the wave of new developments and was always keen to push the limits. He was a brilliant communicator, always full of engaging enthusiasm.

Mars Colonization Plan: The Possibility And Scheme For Appropriation On Mars

In the dawn of space era, State-driven and monopolized the space activities. This was exacerbated by high cost, military interference and the uncertain possibilities of civilian use. Nevertheless, as space technology grew, the enormous benefits created by space activities gradually motivated private companies to spend more capital and to use space for commercial purposes. Recently, two major of private space firms, SpaceX and Mars One reportedly has released their mission to Mars in order to conducted Mars Colonization Plan. On the other hand, the Outer Space Treaty and the rest of Corpus Juris Spatialis clearly prohibits to do appropriation on the Moon and the other Celestial Bodies, including Mars. It will be a new challenge for all legal actors, especially in the sense of the outer space regime, to explore this concept. This study applies normative legal research methodology. This study found: the current Outer Space Treaty particularly related to the non-appropriation principle is not relevant to the development of space technology and activities. Then, in this study the non-appropriation principle will be revisited based on the customary international law mechanism. Second, this study found the suitable scheme of appropriation during Mars Colonization Plan by establishing an Independent entity which authorize and organize the activities and also by implementing several stages in appropriating the Martian areas. Third, this study then proposed legal framework through amending and modernizing the Outer Space Treaty in order to compromise between the non-appropriation principle and the development of space commercialization. Keywords: Corpus Juris Spatialis; Mars Colonization; Non-Appropriation Rencana Kolonisasi Mars: Kemungkinan Dan Skema Pengambilalihan Di Mars Abstrak Di awal era keantariksaan, kegiatan keantariksaan digerakkan dan dimonopoli oleh negara. Ini diperburuk dengan adanya biaya tinggi, campur tangan militer, dan kemungkinan penggunaan oleh sipil yang tidak pasti. Namun, seiring dengan berkembangnya teknologi ruang angkasa, manfaat besar yang diciptakan oleh aktivitas keantariksaan secara bertahap memotivasi perusahaan swasta untuk menghabiskan lebih banyak modal dan menggunakan ruang tersebut untuk tujuan komersial. Baru-baru ini, dua perusahaan keantariksaan besar swasta, SpaceX dan Mars One, dikabarkan telah merilis misi mereka ke Mars dalam rangka melakukan Rencana Kolonosasi Mars (Mars Colonization Plan). Di sisi lain, Outer Space Treaty dan Corpus Juris Spatialis lainnya secara jelas melarang untuk melakukan perampasan di Bulan dan Benda-benda Langit lainnya, termasuk Mars. Ini akan menjadi tantangan baru bagi semua aktor hukum, terutama dalam arti rezim keantariksaan, untuk mendalami konsep ini. Penelitian ini menggunakan metodologi penelitian hukum normatif. Studi ini menemukan: Traktat Luar Angkasa saat ini khususnya terkait dengan prinsip non-apropriasi tidak relevan dengan perkembangan teknologi dan kegiatan keantariksaan. Kemudian, dalam penelitian ini, prinsip non-apropriasi ditinjau kembali berdasarkan mekanisme hukum kebiasaan internasional. Studi ini juga menemukan, skema apropriasi yang sesuai selama Rencana Kolonisasi Mars adalah dengan membentuk entitas Independen yang menguasai dan mengatur kegiatan dan juga dengan menerapkan beberapa tahap dalam mengambil alih wilayah Mars. Studi ini kemudian mengusulkan kerangka hukum melalui amandemen dan modernisasi Traktat Luar Angkasa untuk mengompromikan antara prinsip non-apropriasi dan pengembangan komersialisasi ruang angkasa. Kata kunci: Corpus Juris Spasialis, Kolonisasi Mars, non-Apropriasi.

American Buddhist Protection of Stones in Terms of Climate Change on Mars and Earth

ABSTRACT A number of scientific writers have proposed manipulating the ecology of Mars in order to make the planet more comfortable for future immigrants from Earth. However, the ethical acceptability of such ‘terraforming’ proposals remains unresolved. In response, in this article I explore some of these scientific proposals through the lens provided by Buddhist environmental ethics that are quantitatively expressed by practitioners in the ethnographic field of the United States. What I find is that contemporary Buddhists combine philosophical notions of interconnectedness with moral considerations not to harm others and then creatively extend this combined sensibility to the protection specifically of abiotic features of Mars. In so doing, these Buddhists significantly reject proposals to alter the Martian ecology planet-wide as beyond the ethical right of humans. Along the way these Buddhists also, importantly, provide an innovative basis for enriching Buddhist environmental ethical protection of abiotic locations, and this strengthening can assist in mitigating climate change on Earth.

Nucleic Acid Extraction and Sequencing from Low-Biomass Synthetic Mars Analog Soils for In Situ Life Detection.

Recent studies regarding the origins of life and Mars-Earth meteorite transfer simulations suggest that biological informational polymers, such as nucleic acids (DNA and RNA), have the potential to provide unambiguous evidence of life on Mars. To this end, we are developing a metagenomics-based life-detection instrument which integrates nucleic acid extraction and nanopore sequencing: the Search for Extra-Terrestrial Genomes (SETG). Our goal is to isolate and sequence nucleic acids from extant or preserved life on Mars in order to determine if a particular genetic sequence (1) is distantly related to life on Earth, indicating a shared ancestry due to lithological exchange, or (2) is unrelated to life on Earth, suggesting a convergent origins of life on Mars. In this study, we validate prior work on nucleic acid extraction from cells deposited in Mars analog soils down to microbial concentrations (i.e., 104 cells in 50 mg of soil) observed in the driest and coldest regions on Earth. In addition, we report low-input nanopore sequencing results from 2 pg of purified Bacillus subtilis spore DNA simulating ideal extraction yields equivalent to 1 ppb life-detection sensitivity. We achieve this by employing carrier sequencing, a method of sequencing sub-nanogram DNA in the background of a genomic carrier. After filtering of carrier, low-quality, and low-complexity reads we detected 5 B. subtilis reads, 18 contamination reads (including Homo sapiens), and 6 high-quality noise reads believed to be sequencing artifacts.

Atmospheric entry heating of micrometeorites at Earth and Mars: Implications for the survival of organics

AbstractThe atmospheric entry heating of micrometeorites (MMs) can significantly alter their pre‐existing mineralogy, texture, and organic material. The degree of heating depends predominantly on the gravity and atmospheric density of the planet on which they fall. For particles falling on Earth, the alteration can be significant, leading to the destruction of much of the pre‐entry organics; however, the weaker gravity and thinner atmosphere of Mars enhance the survival of MMs and increase the fraction of particles that preserve organic material. This paper investigates the entry heating of MMs on the Earth and Mars in order to examine the MM population on each planet and give insights into the survival of extraterrestrial organic material. The results show that particles reaching the surface of Mars experience a lower peak temperature compared to Earth and, therefore, experience less evaporative mass loss. Of the particles which reach the surface, 68.2% remain unmelted on Mars compared to only 22.8% on Earth. Due to evaporative mass loss, unmelted particles that reach the surface of Earth are restricted to sizes <70 μm whereas particles >475 μm survive unmelted on Mars. Approximately 10% of particles experience temperatures below ~800 K, that is, the sublimation temperature of refractory organics found in MMs. On Earth, this fraction is significantly lower with less than 1% expected to remain below this temperature. Lower peak temperatures coupled with the larger sizes of particles surviving without significant heating on Mars suggest a much higher fraction of organic material surviving to the Martian surface.

Sletanje na Mars

More than 40 years after the first successful landing on Mars, in situ exploration of its surface continues to be a huge scientific and technological challenge. This primarily refers to Martian southern highlands, extending over a large part of its southern hemisphere, where no successful landing has been achieved so far. On the other hand, in the northern lowlands, which cover almost entire northern hemisphere, 7 successful landings have been completed. This difference is a consequence of the specific topography of the Martian surface due to the so-called global or hemispherical dichotomy of Mars, which represents a unique feature in the Solar system. Due to the difference in elevations of the surface, a spacecraft trying land on the southern highlands have a thinner atmosphere layer which can be used for dissipation of kinetic energy. Since the spacecraft from an interplanetary trajectory enter the atmosphere with hyperbolic velocities, their kinetic energy is extremely large and the ability to reduce it through interaction with the atmosphere is crucial for safe landing, especially at sites with high elevation. It is estimated that the southern highlands are billions of years older than the northern lowlands, which were exposed to strong volcanic activity in the relatively recent past. This huge difference in age is a motivation for exploration of the entire surface of Mars in order to understand its complex geological evolution. In addition, a large number of open basins, which were discovered on the southern lowlands, indicate that these regions in the past could have been covered with liquid water, which is one of the most important reasons for exploring these locations. The analysis of the seasonal and daily variations of the Martian atmosphere confirms that, it is possible to land on these high locations by using current technology, with the necessity of optimization of the conditions under which spacecraft enter the atmosphere, in order to maximize the benefits from these specificities of Mars.

Probing the chemical and mineralogical characteristics of the Martian meteorite NWA 7397 through μRaman and μXRF non-destructively

AbstractMartian meteorites have valuable information about past geological processes on Mars. In this particular case, the sample used was the Martian meteorite Northwest Africa (NWA) 7397. The main objective was to conduct preliminary analyses of the sample that was able to provide mineralogical characteristics in a non-destructive way. These meteorite NWA 7397 analyses were performed using two analytical techniques, μRaman and μXRF. Through the techniques used it was possible to suggest the presence of chromite, ilmenite, magnetite and forsterite minerals. These minerals seem to have a correspondence to one another in relation to the process that formed them. Thus, the information generated by these analytical techniques can contribute significantly by providing information on the history of Mars in order to have relevance to the areas of Astrobiology and Planetary Sciences.

A rover's geologic field campaign: Exploration of the Kimberley by Curiosity

AbstractThe Mars Science Laboratory Curiosity rover undertook comprehensive exploration of the Kimberley waypoint within Gale crater, Mars in order to understand its context within the larger geologic picture of Gale crater and its evidence for past Martian habitability. Coordinated observations from Curiosity's rich science payload revealed important insights into new Martian crustal compositions, the prevalence and diversity of sedimentary processes within Gale crater, and surface erosion rates. Exploration at the Kimberley, in part informed by a decade of orbital observations of Gale crater, underscored the critical synergy between landed and orbital observations and furthered understanding of complex geological processes on Mars.

Changes in the thermosphere and ionosphere of Mars from Viking to MAVEN

AbstractWe compare Viking and Mars Atmosphere and Volatile EvolutioN mission (MAVEN) Neutral Gas and Ion Mass Spectrometer (NGIMS) observations of the thermosphere and ionosphere of Mars in order to test predictions of large variations in conditions over the solar cycle and with season. Substantial differences exist between the Viking observations at solar minimum and near aphelion and the MAVEN NGIMS observations at moderate solar activity and near perihelion. Differences in the O/CO2 ratio, the O+ ionospheric peak, ion densities at high altitude, and neutral and ion scale heights can be attributed to differences in solar activity and season, but the relative importance of solar activity and season for these differences was not established. Current models do not explain the observed differences in the mixing ratios of N, NO, and O2. These results place new constraints on models of how the thermosphere and ionosphere of Mars vary over the solar cycle and with season.

Verifying single-station seismic approaches using Earth-based data: Preparation for data return from the InSight mission to Mars

The planned InSight mission will deliver a single seismic station containing 3-component broadband and short-period sensors to the surface of Mars in 2016. While much of the progress in understanding the Earth and Moon’s interior has relied on the use of seismic networks for accurate location of sources, single station approaches can be applied to data returned from Mars in order to locate events and determine interior structure. In preparation for the data return from InSight, we use a terrestrial dataset recorded at the Global Seismic Network station BFO, located at the Black Forest Observatory in Germany, to verify an approach for event location and structure determination based on recordings of multiple orbit surface waves, which will be more favorable to record on Mars than Earth due to smaller planetary radius and potentially lower background noise. With this approach applied to events near the threshold of observability on Earth, we are able to determine epicentral distance within approximately 1° (corresponding to ∼60km on Mars), and origin time within ∼30s. With back azimuth determined from Rayleigh wave polarization, absolute locations are determined generally within an aperture of 10°, allowing for localization within large tectonic regions on Mars. With these locations, we are able to recover Earth mantle structure within ±5% (the InSight mission requirements for martian mantle structure) using 1D travel time inversions of P and S travel times for datasets of only 7 events. The location algorithm also allows for the measurement of great-circle averaged group velocity dispersion, which we measure between 40 and 200s to scale the expected reliable frequency range of the InSight data from Earth to Mars data. Using the terrestrial data, we are able to resolve structure down to ∼200km, but synthetic tests demonstrate we should be able to resolve martian structure to ∼400km with the same frequency content given the smaller planetary size.

Heat structure coupling of CUPID and MARS for the multi-scale simulation of the passive auxiliary feedwater system

For the analysis of transient two-phase flows in nuclear reactor components, a three-dimensional thermal hydraulics code, named CUPID, has been developed. In the present study, the CUPID code was coupled with a system analysis code MARS in order to apply it for the multi-scale thermal-hydraulic analysis of the passive auxiliary feedwater system (PAFS). The PAFS is one of the advanced safety features adopted in the Advanced Power Reactor Plus (APR+), which is intended to completely replace the conventional active auxiliary feedwater system. For verification of the coupling and validation of the coupled code, the PASCAL test facility was simulated, which was constructed with an aim of validating the cooling and operational performance of the PAFS. The two-phase flow phenomena of the steam supply system including the condensation inside the heat exchanger tube were calculated by MARS while the natural circulation and the boil-off in the large water pool that contains the heat exchanger tube were simulated by CUPID. This paper presents the description of the PASCAL facility, the coupling method and the simulation results using the coupled code.

Mars science laboratory interplanetary navigaton analysis

The Mars Science Laboratory (MSL) is a NASA rover mission that will be launched in late 2011 and will land on Mars in August of 2012. This paper describes the analyses performed to validate the navigation system for launch, interplanetary cruise, and approach. MSL will use guidance during its descent into Mars in order to minimize landing dispersions, and therefore will be able to use smaller landing zones that are closer to terrain of high scientific interest. This will require a more accurate delivery of the spacecraft to the atmospheric entry interface, and a late update of the state of the spacecraft at entry. During cruise and approach the spacecraft may perform up to six trajectory correction maneuvers (TCMs), to target to the desired landing site with the required flight path angle at entry. Approach orbit determination covariance analyses have been performed to evaluate the accuracy that can be achieved in delivering the spacecraft to the entry interface point, and to determine how accurately the state of the spacecraft can be predicted to initialize the guidance algorithm. In addition, a sensitivity analysis has been performed to evaluate which factors most contribute to the improvement or degradation of the navigation performance, for both entry flight path angle delivery and entry state knowledge.

Modeling the formation of bright slope deposits associated with gullies in Hale Crater, Mars: Implications for recent liquid water

Our study investigates possible formation mechanisms of the very recent bright gully deposits (BGDs) observed on Mars in order to assess if liquid water was required. We use two models in our assessment: a one-dimensional (1D) kinematic model to model dry granular flows and a two-dimensional (2D) fluid-dynamic model, FLO-2D ( O’Brien et al., 1993, FLO Engineering), to model water-rich and wet sediment-rich flows. Our modeling utilizes a high-resolution topographic model generated from a pair of images acquired by the High Resolution Imaging Science Experiment (HiRISE) aboard the Mars Reconnaissance Orbiter. For the 1D kinematic modeling of dry granular flows, we examine a range of particle sizes, flow thicknesses, initial velocities, flow densities, and upslope initiation points to examine how these parameters affect the flow run-out distances of the center of mass of a flow. Our 1D modeling results show that multiple combinations of realistic parameters could produce dry granular flows that travel to within the observed deposits’ boundaries. We run the 2D fluid-dynamic model, FLO-2D, to model both water-rich and wet sediment-rich flows. We vary the inflow volume, inflow location, discharge rate, water-loss rate (water-rich models only), and simulation time and examine the resulting maximum flow depths and velocities. Our 2D modeling results suggest that both wet sediment-rich and water-rich flows could produce the observed bright deposits. Our modeling shows that the BGDs are not definitive evidence of recent liquid water on the surface of Mars.

A numerical study of the Schumann resonances in Mars with the FDTD method

Natural electromagnetic waves generated near the surface by electrostatic discharges in dust storms (dust devils) or by geological activity could be trapped in the resonant cavity formed by the surface and lower ionosphere of Mars, as it occurs on Earth giving rise to Schumann resonances. The finite difference time‐domain technique (FDTD) is applied to model the atmosphere of Mars in order to determine Schumann resonant frequencies, and natural electromagnetic fields at the extremely low frequency range (ELF). A numerical tool is provided to analyze the electrical conductivity profile of the Martian atmosphere, with the aim of obtaining Schumann resonance frequencies and their dependence on various ionization sources and solar activity. The effect of local enhancement of conductivity profile at several altitudes is also studied to understand its consequences on Schumann resonances. A criterion to fix the upper limit of the numerical model is established from these results.

Sulfates on Mars: A systematic Raman spectroscopic study of hydration states of magnesium sulfates

The martian orbital and landed surface missions, OMEGA on Mar Express and the two Mars Explorations Rovers, respectively, have yielded evidence pointing to the presence of magnesium sulfates on the martian surface. In situ identification of the hydration states of magnesium sulfates, as well as the hydration states of other Ca- and Fe- sulfates, will be crucial in future landed missions on Mars in order to advance our knowledge of the hydrologic history of Mars as well as the potential for hosting life on Mars. Raman spectroscopy is a technique well-suited for landed missions on the martian surface. In this paper, we report a systematic study of the Raman spectra of the hydrates of magnesium sulfate. Characteristic and distinct Raman spectral patterns were observed for each of the 11 distinct hydrates of magnesium sulfates, crystalline and non-crystalline. The unique Raman spectral features along with the general tendency of the shift of the position of the sulfate ν 1 band towards higher wavenumbers with a decrease in the degree of hydration allow in situ identification of these hydrated magnesium sulfates from the raw Raman spectra of mixtures. Using these Raman spectral features, we have started the study of the stability field of hydrated magnesium sulfates and the pathways of their transformations at various temperature and relative humidity conditions. In particular we report on the Raman spectrum of an amorphous hydrate of magnesium sulfate (MgSO 4·2H 2O) that may have specific relevance for the martian surface.

Mineralogy and evolution of the surface of Mars: A review

We review the mineralogy of the surface of Mars, using data from various sources, including in situ characterisations performed by landers, remote observations from orbit, and studies of the SNC meteorites. We also discuss the possible alteration processes and the factor controlling them, and try to relate the mineralogical observations to the chemical evolution of the surface materials on Mars in order to identify the dominant process(es). Then we try to describe a possible chemical and mineralogical evolution of the surface materials, resulting from weathering driven by the abundance and activity of water. Even if weathering is the dominant process responsible for the surface evolution, all observations suggest that it is strongly affected locally in time and space by various other processes including hydrothermalism, volcanism, evaporites, meteoritic impacts and aeolian erosion. Nevertheless, the observed phases on the surface of Mars globally depend on the evolution of the weathering conditions. This hypothesis, if confirmed, could give a new view of the evolution of the martian surface, roughly in three steps. The first would correspond to clay-type weathering process in the Noachian, under a probable thick H 2O/CO 2-rich atmosphere. Then, during the Hesperian when water became scarcer and its activity sporadic, linked to volcanic activity, sulfate-type acidic weathering process would have been predominant. The third period would be like today, a very slow weathering by strongly oxidising agents (H 2O 2, O 2) in cold and dry conditions, through solid-gas or solid-films of water resulting frost-thaw and/or acid fog. This would favour poorly crystalline phases, mainly iron (oxy) hydroxides. But in this scenario many questions remain about the transition between these processes, and about the factors affecting the evolution of the weathering process.

Digital Topography Models for Martian Surfaces

We propose to use an unsupervised automated classification of topographic features on Mars in order to speed up geomorphic and geologic mapping of the planet. We construct a digital topography model (DTM), a multilayer grid that stores various kinds of topographical information for every pixel in a site. The method uses a probabilistic clustering algorithm to assign topographically meaningful labels to all pixels in the DTM. The results are displayed as a thematic map of topography. Resultant topographical features are characterized and compared using statistics of their constituent pixels. We demonstrate the usage of our method by classifying and characterizing the topography of a landscape in the Tisia Valles region on Mars. We discuss extensions and further applications of our method.

On the possibility of measuring the solar oblateness and some relativistic effects from planetary ranging

In this paper we first calculate the post-Newtonian gravitoelectric secular rate of the mean anomaly of a test particle freely orbiting a spherically symmetric central mass. Then, we propose a novel approach to suitably combine the presently available planetary ranging data to Mercury, Venus and Mars in order to determine, simultaneously and independently of each other, the Sun's quadrupole mass moment J_2 and the secular advances of the perihelion and the mean anomaly. This would also allow to obtain the PPN parameters gamma and beta independently. We propose to analyze the time series of three linear combinations of the experimental residuals of the rates of the nodes, the longitudes of perihelia and mean anomalies of Mercury, Venus and Mars built up in order to absorb the secular precessions induced by the solar oblateness and the post-Newtonian gravitoelectric forces. The values of the three investigated parameters can be obtained by fitting the expected linear trends with straight lines, determining their slopes in arcseconds per century and suitably normalizing them. According to the present-day EPM2000 ephemerides accuracy, the obtainable precision would be of the order of 10^-4-10^-5 for the PPN parameters and, more interestingly, of 10^-9 for J_2. The future BepiColombo mission should improve the Mercury's orbit by one order of magnitude.

Radiative‐convective model of warming Mars with artificial greenhouse gases

Artificial greenhouse gases could be used to warm Mars in order to make it habitable. Here we present new laboratory measurements of the thermal infrared absorption spectra of seven artificial greenhouse gases (CF4, C2F6, C3F8, SF6, CF3Cl, CF3Br, CF2Cl2) at concentrations from 10−7 up to unity. We used a radiative‐convective multilayer model to compute the warming caused by a mixture of the four fluorine‐based greenhouse gases. The results show that for current Mars, C3F8 produces the largest warming: 0.56 K and 33.5 K for partial pressures of 10−3 Pa and 1 Pa, respectively. Averaged over partial pressures from 0.01 to 1 Pa, the range of most interest for planetary ecosynthesis, CF4, C2F6, and SF6 were 17%, 49%, and 48% as effective as C3F8, respectively. The optimal mixture of the four fluorine‐based greenhouse gases, taking into account the overlapping of their absorption bands, was 16% more effective than pure C3F8, averaged over the range 0.01 Pa to 1 Pa. Energy balance calculations suggest that the addition of ∼0.2 Pa of the best greenhouse gases mixture or ∼0.4 Pa of C3F8 would shift the equilibrium to the extent that CO2 would no longer be stable at the Martian poles and a runaway greenhouse effect would result.