| 1. |
- Amini, Kasra, et al.
(författare)
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Design of a set of habitat units and the corresponding surrounding cluster for long-term scientific missions in the pre-terraforming era on mars
- 2022
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Ingår i: Icarus. - : Elsevier BV. - 0019-1035 .- 1090-2643. ; 385, s. 115119-
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Tidskriftsartikel (refereegranskat)abstract
- We are living in a point in the history of science and technology, where space travel for research and settlement is inevitable. As the utmost crucial technology pieces for leaving Earth and travelling into the cosmos is being established one after another, it is just a matter of decades, until it all gets integrated together, solving the engineering problems ahead of the way and being able to step on the planets and moons of the solar system. In this quest, as has been the case for most of the technological advancements so far, there ought to be mind experiments, in which one skips one step, assumes the availability of responses to the skipped-over step, and searches for the solution to the questions of the next level. This way, by getting passed the first, i.e. current step, the solution to the next one is already available. The current manuscript is addressing this very 'next step', on the long path to eventually colonize Mars and inhabit it for long-term research-based missions; let it be for terraforming, or other agenda to be defined by the research strategists, then. And as mentioned earlier, the current step; being setting foot on Mars, is well-deservedly taken for granted, as is to come forth undoubtedly. Having that realized, we might find ourselves faced by the engineering complexities of surviving and thriving on Mars, which is the subject matter of the current research, from the aspect point of space technological and architectural design. The design procedure beginning from setting the philosophy of design upon the concerns of sustaining in the hostile environment of Mars, to the stepwise emergence of the final design of a cluster of Martian Habitat Units (MHUs) considering the high-criteria of the case, is the subject matter covered in this manuscript.
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| 2. |
- Attree, Nicholas, et al.
(författare)
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Gas flow in Martian spider formation
- 2021
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Ingår i: Icarus. - : Elsevier. - 0019-1035 .- 1090-2643. ; 359
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Tidskriftsartikel (refereegranskat)abstract
- Martian araneiform terrain, located in the Southern polar regions, consists of features with central pits and radial troughs which are thought to be associated with the solid state greenhouse effect under a CO2 ice sheet. Sublimation at the base of this ice leads to gas buildup, fracturing of the ice and the flow of gas and entrained regolith out of vents and onto the surface. There are two possible pathways for the gas: through the gap between the ice slab and the underlying regolith, as proposed by Kieffer (2007), or through the pores of a permeable regolith layer, which would imply that regolith properties can control the spacing between adjacent spiders, as suggested by Hao et al. (2019). We test this hypothesis quantitatively in order to place constraints on the regolith properties. Based on previously estimated flow rates and thermophysical arguments, we suggest that there is insufficient depth of porous regolith to support the full gas flow through the regolith. By contrast, free gas flow through a regolith–ice gap is capable of supplying the likely flow rates for gap sizes on the order of a centimetre. This size of gap can be opened in the centre of a spider feature by gas pressure bending the overlying ice slab upwards, or by levitating it entirely as suggested in the original Kieffer (2007) model. Our calculations therefore support at least some of the gas flowing through a gap opened between the regolith and ice. Regolith properties most likely still play a role in the evolution of spider morphology, by regolith cohesion controlling the erosion of the central pit and troughs, for example.
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| 3. |
- Binzel, R.P., et al.
(författare)
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Compositional distributions and evolutionary processes for the near-Earth object population: Results from the MIT-Hawaii Near-Earth Object Spectroscopic Survey (MITHNEOS)
- 2019
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Ingår i: Icarus. - : Elsevier. - 0019-1035 .- 1090-2643. ; 324, s. 41-76
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Tidskriftsartikel (refereegranskat)abstract
- Advancing technology in near-infrared instrumentation and dedicated planetary telescope facilities have enabled nearly two decades of reconnoitering the spectral properties for near-Earth objects (NEOs). We report measured spectral properties for more than 1000 NEOs, representing >5 percent of the currently discovered population. Thermal flux detected below 2.5 microns allows us to make albedo estimates for nearly 50 objects, including two comets. Additional spectral data are reported for more than 350 Mars-crossing asteroids. Most of these measurements were achieved through a collaboration between researchers at the Massachusetts Institute of Technology and the University of Hawaii, with full cooperation of the NASA Infrared Telescope Facility (IRTF) on Mauna Kea. We call this project the MIT-Hawaii Near-Earth Object Spectroscopic Survey (MITHNEOS; myth-neos). While MITHNEOS has continuously released all spectral data for immediate use by the scientific community, our objectives for this paper are to: (1) detail the methods and limits of the survey data, (2) formally present a compilation of results including their taxonomic classification within a single internally consistent framework, (3) perform a preliminary analysis on the overall population characteristics with a concentration toward deducing key physical processes and identifying their source region for escaping the main belt. Augmenting our newly published measurements are the previously published results from the broad NEO community, including many results graciously shared by colleagues prior to formal publication. With this collective data set, we find the near-Earth population matches the diversity of the main-belt, with all main-belt taxonomic classes represented in our sample. Potentially hazardous asteroids (PHAs) as well as the subset of mission accessible asteroids (ΔV≤ 7 km/s) both appear to be a representative mix of the overall NEO population, consistent with strong dynamical mixing for the population that interacts most closely with Earth. Mars crossers, however, are less diverse and appear to more closely match the inner belt population from where they have more recently diffused. The fractional distributions of major taxonomic classes (60% S, 20% C, 20% other) appear remarkably constant over two orders of magnitude in size (10 km to 100 m), which is eight orders of magnitude in mass, though we note unaccounted bias effects enter into our statistics below about 500m. Given the range of surface ages, including possible refreshment by planetary encounters, we are able to identify a very specific space weathering vector tracing the transition from Q- to Sq- to S-types that follows the natural dispersion for asteroid spectra mapped into principal component space. We also are able to interpret a shock darkening vector that may account for some objects having featureless spectra. Space weathering effects for C-types are complex; these results are described separately by Lantz, Binzel, DeMeo. (2018, Icarus 302, 10-17). Independent correlation of dynamical models with taxonomic classes map the escape zones for NEOs to main-belt regions consistent with well established heliocentric compositional gradients. We push beyond taxonomy to interpret our visible plus near-infrared spectra in terms of the olivine and pyroxene mineralogy consistent with the H, L, and LL classes of ordinary chondrites meteorites. Correlating meteorite interpretations with dynamical escape region models shows a preference for LL chondrites to arrive from the ν6 resonance and H chondrites to have a preferential signature from the mid-belt region (3:1 resonance). L chondrites show some preference toward the outer belt, but not at a significant level. We define a Space Weathering Parameter as a continuous variable and find evidence for step-wise changes in space weathering properties across different planet crossing zones in the inner solar system. Overall we hypothesize the relative roles of planetary encounters, YORP spin-up, and thermal cycling across the inner solar system.
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| 4. |
- Biver, N., et al.
(författare)
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Radio observations of Comet 9P/Tempel 1 before and after Deep Impact
- 2007
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Ingår i: Icarus. - : Elsevier BV. - 1090-2643 .- 0019-1035. ; 191:2, s. 494-512
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Tidskriftsartikel (refereegranskat)abstract
- Comet 9P/Tempel 1 was the target of a multi-wavelength worldwide investigation in 2005. The NASA Deep Impact mission reached the comet on 4.24 July 2005, delivering a 370-kg impactor which hit the comet at 10.3 km s -1 . Following this impact, a cloud of gas and dust was excavated from the comet nucleus. The comet was observed in 2005 prior to and after the impact, at 18-cm wavelength with the Nançay radio telescope, in the millimeter range with the IRAM and CSO radio telescopes, and at 557 GHz with the Odin satellite. OH observations at Nançay provided a 4-month monitoring of the outgassing of the comet from March to June, followed by the observation of H 2 O with Odin from June to August 2005. The peak of outgassing was found to be around 1 × 10 28 molec. s -1 between May and July. Observations conducted with the IRAM 30-m radio telescope in May and July 2005 resulted in detections of HCN, CH 3 OH and H 2 S with classical abundances relative to water (0.12, 2.7 and 0.5%, respectively). In addition, a variation of the HCN production rate with a period of 1.73 ± 0.10 days was observed in May 2005, consistent with the 1.7-day rotation period of the nucleus. The phase of these variations, as well as those of CN seen in July by Jehin et al. [Jehin, E., Manfroid, J., Hutsemékers, D., Cochran, A.L., Arpigny, C., Jackson, W.M., Rauer, H., Schulz, R., Zucconi, J.-M., 2006. Astrophys. J. 641, L145-L148], is consistent with a rotation period of the nucleus of 1.715 days and a strong variation of the outgassing activity by a factor 3 from minimum to maximum. This also implies that the impact took place on the rising phase of the "natural" outgassing which reached its maximum ≈4 h after the impact. Post-impact observations at IRAM and CSO did not reveal a significant change of the outgassing rates and relative abundances, with the exception of CH 3 OH which may have been more abundant by up to one order of magnitude in the ejecta. Most other variations are linked to the intrinsic variability of the comet. The Odin satellite monitored nearly continuously the H 2 O line at 557 GHz during the 38 h following the impact on the 4th of July, in addition to weekly monitoring. Once the periodic variations related to the nucleus rotation are removed, a small increase of outgassing related to the impact is present, which corresponds to the release of ≈ 5000 ± 2000 tons of water. Two other bursts of activity, also observed at other wavelengths, were seen on 23 June and 7 July; they correspond to even larger releases of gas. © 2006 Elsevier Inc. All rights reserved.
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| 5. |
- Biver, N., et al.
(författare)
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Radio observations of Comet 9P/Tempel 1 before and after Deep Impact
- 2007
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Ingår i: Icarus. - : Elsevier BV. - 1090-2643 .- 0019-1035. ; 187:1, s. 253-271
-
Tidskriftsartikel (refereegranskat)abstract
- Comet 9P/Tempel 1 was the target of a multi-wavelength worldwide investigation in 2005. The NASA Deep Impact mission reached the comet on 4.24 July 2005, delivering a 370-kg impactor which hit the comet at 10.3 km s -1 . Following this impact, a cloud of gas and dust was excavated from the comet nucleus. The comet was observed in 2005 prior to and after the impact, at 18-cm wavelength with the Nançay radio telescope, in the millimeter range with the IRAM and CSO radio telescopes, and at 557 GHz with the Odin satellite. OH observations at Nançay provided a 4-month monitoring of the outgassing of the comet from March to June, followed by the observation of H 2 O with Odin from June to August 2005. The peak of outgassing was found to be around 1 × 10 28 molec. s -1 between May and July. Observations conducted with the IRAM 30-m radio telescope in May and July 2005 resulted in detections of HCN, CH 3 OH and H 2 S with classical abundances relative to water (0.12, 2.7 and 0.5%, respectively). In addition, a variation of the HCN production rate with a period of 1.73 ± 0.10 days was observed in May 2005, consistent with the 1.7-day rotation period of the nucleus. The phase of these variations, as well as those of CN seen in July by Jehin et al. [Jehin, E., Manfroid, J., Hutsemékers, D., Cochran, A.L., Arpigny, C., Jackson, W.M., Rauer, H., Schulz, R., Zucconi, J.-M., 2006. Astrophys. J. 641, L145-L148], is consistent with a rotation period of the nucleus of 1.715 days and a strong variation of the outgassing activity by a factor 3 from minimum to maximum. This also implies that the impact took place on the rising phase of the "natural" outgassing which reached its maximum ≈4 h after the impact. Post-impact observations at IRAM and CSO did not reveal a significant change of the outgassing rates and relative abundances, with the exception of CH 3 OH which may have been more abundant by up to one order of magnitude in the ejecta. Most other variations are linked to the intrinsic variability of the comet. The Odin satellite monitored nearly continuously the H 2 O line at 557 GHz during the 38 h following the impact on the 4th of July, in addition to weekly monitoring. Once the periodic variations related to the nucleus rotation are removed, a small increase of outgassing related to the impact is present, which corresponds to the release of ≈ 5000 ± 2000 tons of water. Two other bursts of activity, also observed at other wavelengths, were seen on 23 June and 7 July; they correspond to even larger releases of gas. © 2006 Elsevier Inc. All rights reserved.
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| 6. |
- Brain, D., et al.
(författare)
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A comparison of global models for the solar wind interaction with Mars
- 2010
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Ingår i: Icarus. - : Elsevier BV. - 0019-1035 .- 1090-2643. ; 206:1, s. 139-151
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Tidskriftsartikel (refereegranskat)abstract
- We present initial results from the first community-wide effort to compare global plasma interaction model results for Mars. Seven modeling groups participated in this activity, using MHD, multi-fluid, and hybrid assumptions in their simulations. Moderate solar wind and solar EUV conditions were chosen, and the conditions were implemented in the models and run to steady state. Model output was compared in three ways to determine how pressure was partitioned and conserved in each model, the location and asymmetry of plasma boundaries and pathways for planetary ion escape, and the total escape flux of planetary oxygen ions. The two participating MHD models provided similar results, while the five sets of multi-fluid and hybrid results were different in many ways. All hybrid results, however, showed two main channels for oxygen ion escape (a pickup ion 'plume' in the hemisphere toward which the solar wind convection electric field is directed, and a channel in the opposite hemisphere of the central magnetotail), while the MHD models showed one (a roughly symmetric channel in the central magnetotail). Most models showed a transition from an upstream region dominated by plasma dynamic pressure to a magnetosheath region dominated by thermal pressure to a low altitude region dominated by magnetic pressure. However, calculated escape rates for a single ion species varied by roughly an order of magnitude for similar input conditions, suggesting that the uncertainties in both the current and integrated escape over martian history as determined by models are large. These uncertainties are in addition to those associated with the evolution of the Sun, the martian dynamo, and the early atmosphere, highlighting the challenges we face in constructing Mars' past using models.
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| 7. |
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| 8. |
- Carlsson, Ella, et al.
(författare)
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Mass composition of the escaping plasma at Mars
- 2006
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Ingår i: Icarus. - : Elsevier BV. - 0019-1035 .- 1090-2643. ; 182:2, s. 320-328
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Tidskriftsartikel (refereegranskat)abstract
- Data from the Ion Mass Analyzer (IMA) sensor of the ASPERA-3 instrument suite on Mars Express have been analyzed to determine the mass composition of the escaping ion species at Mars. We have examined 77 different ion-beam events and we present the results in terms of flux ratios between the following ion species: CO2+/O+ and O-2(+)/O+. The following ratios averaged over all events and energies were identified: CO2+/O+ = 0.2 and O-2(+)/O+ = 0.9. The values measured are significantly higher, by a factor of 10 for O-2(+)/O+, than a contemporary modeled ratio for the maximum fluxes which the martian ionosphere can supply. The most abundant ion species was found to be O+, followed by O-2(+) and CO2+. We estimate the loss of CO2+ to be 4.0 x 10(24) s(-1) (0.29 kg s(-1)) by using the previous measurements of Phobos-2 in our calculations. The dependence of the ion ratios in relation to their energy ranges we studied, 0.3-3.0 keV, indicated that no clear correlation was found.
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| 9. |
- Cordoba-Jabonero, Carmen, et al.
(författare)
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Radiative habitable zones in martian polar environments
- 2005
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Ingår i: Icarus. - : Elsevier. - 0019-1035 .- 1090-2643. ; 175:2, s. 360-371
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Tidskriftsartikel (refereegranskat)abstract
- The biologically damaging solar ultraviolet (UV) radiation (quantified by the DNA-weighted dose) reaches the martian surface in extremely high levels. Searching for potentially habitable UV-protected environments on Mars, we considered the polar ice caps that consist of a seasonally varying CO2 ice cover and a permanent H2O ice layer. It was found that, though the CO2 ice is insufficient by itself to screen the UV radiation, at ∼1 m depth within the perennial H2O ice the DNA-weighted dose is reduced to terrestrial levels. This depth depends strongly on the optical properties of the H2O ice layers (for instance snow-like layers). The Earth-like DNA-weighted dose and Photosynthetically Active Radiation (PAR) requirements were used to define the upper and lower limits of the northern and southern polar Radiative Habitable Zone (RHZ) for which a temporal and spatial mapping was performed. Based on these studies we conclude that photosynthetic life might be possible within the ice layers of the polar regions. The thickness varies along each martian polar spring and summer between ∼1.5 and 2.4 m for H2O ice-like layers, and a few centimeters for snow-like covers. These martian Earth-like radiative habitable environments may be primary targets for future martian astrobiological missions. Special attention should be paid to planetary protection, since the polar RHZ may also be subject to terrestrial contamination by probes.
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| 10. |
- Cousin, A., et al.
(författare)
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Compositions of coarse and fine particles in martian soils at gale: A window into the production of soils
- 2015
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Ingår i: Icarus. - : Elsevier BV. - 0019-1035 .- 1090-2643. ; 249, s. 22-42
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Tidskriftsartikel (refereegranskat)abstract
- The ChemCam instrument onboard the Curiosity rover provides for the first time an opportunity to study martian soils at a sub-millimeter resolution. In this work, we analyzed 24 soil targets probed by ChemCam during the first 250 sols on Mars. Using the depth profile capability of the ChemCam LIBS (Laser-Induced Breakdown Spectroscopy) technique, we found that 45% of the soils contained coarse grains (>500 μm). Three distinct clusters have been detected: Cluster 1 shows a low SiO2 content; Cluster 2 corresponds to coarse grains with a felsic composition, whereas Cluster 3 presents a typical basaltic composition. Coarse grains from Cluster 2 have been mostly observed exposed in the vicinity of the landing site, whereas coarse grains from Clusters 1 and 3 have been detected mostly buried, and were found all along the rover traverse. The possible origin of these coarse grains was investigated. Felsic (Cluster 2) coarse grains have the same origin as the felsic rocks encountered near the landing site, whereas the origin of the coarse grains from Clusters 1 and 3 seems to be more global. Fine-grained soils (particle size < laser beam diameter which is between 300 and 500 μm) show a homogeneous composition all along the traverse, different from the composition of the rocks encountered at Gale. Although they contain a certain amount of hydrated amorphous component depleted in SiO2, possibly present as a surface coating, their overall chemical homogeneity and their close-to-basaltic composition suggest limited, or isochemical alteration, and a limited interaction with liquid water. Fine particles and coarse grains from Cluster 1 have a similar composition, and the former could derive from weathering of the latter. Overall martian soils have a bulk composition between that of fine particles and coarse grains. This work shows that the ChemCam instrument provides a means to study the variability of soil composition at a scale not achievable by bulk chemical analyses.
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