REMS: The Environmental Sensor Suite for the Mars Science Laboratory Rover

The Rover Environmental Monitoring Station (REMS) will investigate environmental factors directly tied to current habitability at the Martian surface during the Mars Science Laboratory (MSL) mission. Three major habitability factors are addressed by REMS: the thermal environment, ultraviolet irradiation, and water cycling. The thermal environment is determined by a mixture of processes, chief amongst these being the meteorological. Accordingly, the REMS sensors have been designed to record air and ground temperatures, pressure, relative humidity, wind speed in the horizontal and vertical directions, as well as ultraviolet radiation in different bands. These sensors are distributed over the rover in four places: two booms located on the MSL Remote Sensing Mast, the ultraviolet sensor on the rover deck, and the pressure sensor inside the rover body. Typical daily REMS observations will collect 180 minutes of data from all sensors simultaneously (arranged in 5 minute hourly samples plus 60 additional minutes taken at times to be decided during the course of the mission). REMS will add significantly to the environmental record collected by prior missions through the range of simultaneous observations including water vapor; the ability to take measurements routinely through the night; the intended minimum of one Martian year of observations; and the first measurement of surface UV irradiation. In this paper, we describe the scientific potential of REMS measurements and describe in detail the sensors that constitute REMS and the calibration procedures.     

Evolution of Dst index,cosmic rays and global temperature during solar cycles 20–23

We have studied conditions in interplanetary space, which can have an influence on galactic cosmic ray (CR) and climate change. In this connection the solar wind and interplanetary magnetic field parameters and cosmic ray variations have been compared with geomagnetic activity represented by the equatorial Dst index from the beginning 1965 to the end of 2012. Dst index is commonly used as the solar wind–magnetosphere–ionosphere interaction characteristic. The important drivers in interplanetary medium which have effect on cosmic rays as CMEs (coronal mass ejections) and CIRs (corotating interaction regions) undergo very strong changes during their propagation to the Earth. Because of this CMEs, coronal holes and the solar spot numbers (SSN) do not adequately reflect peculiarities concerned with the solar wind arrival to 1 AU. Therefore, the geomagnetic indices have some inestimable advantage as continuous series other the irregular solar wind measurements. We have compared the yearly average variations of Dst index and the solar wind parameters with cosmic ray data from Moscow, Climax, and Haleakala neutron monitors during the solar cycles 20–23. The descending phases of these solar cycles (CSs) had the long-lasting solar wind high speed streams occurred frequently and were the primary contributors to the recurrent Dst variations. They also had effects on cosmic rays variations. We show that long-term Dst variations in these solar cycles were correlated with the cosmic ray count rate and can be used for study of CR variations. Global temperature variations in connection with evolution of Dst index and CR variations is discussed.     

Dust Phenomena Relating to Airless Bodies

Airless bodies are directly exposed to ambient plasma and meteoroid fluxes, making them characteristically different from bodies whose dense atmospheres protect their surfaces from such fluxes. Direct exposure to plasma and meteoroids has important consequences for the formation and evolution of planetary surfaces, including altering chemical makeup and optical properties, generating neutral gas and/or dust exospheres, and leading to the generation of circumplanetary and interplanetary dust grain populations. In the past two decades, there have been many advancements in our understanding of airless bodies and their interaction with various dust populations. In this paper, we describe relevant dust phenomena on the surface and in the vicinity of airless bodies over a broad range of scale sizes from \(\sim10^{-3}~\mbox{km}\) to \(\sim10^{3}~\mbox{km}\), with a focus on recent developments in this field.     

Isothermal study of effusion cooling flows using a large eddy simulation approach

An isothermal numerical study of effusion cooling flow is conducted using a large eddy simulation(LES) approach.Two main types of cooling are considered,namely tangential film cooling and oblique patch effusion cooling.To represent tangential film cooling,a simplified model of a plane turbulent wall jet along a flat plate in quiescent surrounding fluid is considered.In contrast to a classic turbulent boundary layer flow,the plane turbulent wall jet possesses an outer free shear flow region,an inner near wall region and an interaction region,characterised by substantial levels of turbulent shear stress transport.These shear stress characteristics hold significant implications for RANS modelling,implications that also apply to more complex tangential film cooling flows with non-zero free stream velocities.The LES technique used in the current study provides a satisfactory overall prediction of the plane turbulent wall jet flow,including the initial transition region,and the characteristic separation of the zero turbulent shear stress and zero shear strain locations.Oblique effusion patch cooling is modelled using a staggered array of 12 rows of effusion holes,drilled at 30° to the flat plate surface.The effusion holes connect two channels separated by the flat plate.Specifically,these comprise of a channel representing the combustion chamber flow and a cooling air supply channel.A difference in pressure between the two channels forces air from the cooling supply side,through the effusion holes,and into the combustion chamber side.Air from successive effusion rows coalesces to form an aerodynamic film between the combustion chamber main flow and the flat plate.In practical applications,this film is used to separate the hot combustion gases from the combustion chamber liner.The numerical model is shown to be capable of accurately predicting the injection,penetration,downstream decay,and coalescence of the effusion jets.In addition,the numerical model captures entrainment of the combustion chamber mainstream flow towards the wall by the presence of the effusion jets.Two contra-rotating vortices,with axes of rotation along the stream-wise direction,are predicted as a result of this entrainment.The presence and characteristics of these vortices are in good agreement with previous published research.      

Solar wind low-energy energetic ion enhancements: A tool to forecast large geomagnetic storms

Predicting the occurrence of large geomagnetic storms more than an hour in advance is an important, yet difficult task. Energetic ion data show enhancements in flux that herald the approach of interplanetary shocks, usually for many hours before the shock arrival. We present a technique for predicting large geomagnetic storms (Kp  7) following the arrival of interplanetary shocks at 1 AU, using low-energy energetic ions (47–65 keV) and solar wind data measured at the L1 libration point. It is based on a study of the relationship between energetic ion enhancements (EIEs) and large geomagnetic storms by Smith et al. [Smith, Z., Murtagh, W., Smithtro, C. Relationship between solar wind low-energy energetic ion enhancements and large geomagnetic storms. J. Geophys. Res. 109, A01110, 2004. doi:10.1029/ 2003JA010044] using data in the rise and maximum of solar cycle 23 (February 1998–December 2000). An excellent correlation was found between storms with Kp  7 and the peak flux of large energetic ion enhancements that almost always (93% of time in our time period) accompany the arrival of interplanetary shocks at L1. However, as there are many more large EIEs than large geomagnetic storms, other characteristics were investigated to help determine which EIEs are likely to be followed by large storms. An additional parameter, the magnitude of the post-shock total magnetic field at the L1 Lagrangian point, is introduced here. This improves the identification of the EIEs that are likely to be followed by large storms. A forecasting technique is developed and tested on the time period of the original study (the training data set). The lead times, defined as the times from the arrival of the shock to the start of the 3-h interval of maximum Kp, are also presented. They range from minutes to more than a day; the average for large storms is 7 h. These times do not include the extra warning time given when the EI flux cross the high thresholds ahead of the shock. Because the data-stream used in the original study is no longer available, we extended the original study (1998–2000) to 2001, in order to: (a) investigate EIEs in 2001; (b) present a validation of the technique on an independent data set; (c) compare the results based on the original (P1) energy channel to those of the replacement (P1′) and (d), determine new EIE thresholds for forecasting geomagnetic storms using P1′ data. The verification of this P1′ training data set is also presented, together with lead times.     

Sounding rocket developments in Spain

This paper contemplates the efforts and developments in the field of sounding rockets carried out in Spain from the decade of the 1960s to the early 1990s when the use of such vehicles was abandoned worldwide.The initial sounding rocket planning within the National Space Research Programs around 1964 (when Spain joined ESRO) is presented.The status of the rocket technology in Spain in 1964 is analysed, reviewing the main technology gaps and the way they were filled to make the planned developments possible.Three Spanish sounding rockets are presented: the INTA-255 (150 km apogee with formative objectives, first launched in 1969), the INTA-300 (300 km apogee with high characteristics and commercial capabilities, first launched in 1974) and the INTA-100 (115 km apogee being finally a totally national product, first launched in 1980).Some guided rocket vehicle projects which were based, on some way, on the previous sounding rockets activities are also mentioned in this paper.     

Spiders: water-driven erosive structures in the southern hemisphere of Mars

Recent data from space missions reveal that there are ongoing climatic changes and erosive processes that continuously modify surface features of Mars. We have investigated the seasonal dynamics of a number of morphological features located at Inca City, a representative area at high southern latitude that has undergone seasonal processes. By integrating visual information from the Mars Orbiter Camera on board the Mars Global Surveyor and climatic cycles from a Mars' General Circulation Model, and considering the recently reported evidence for the presence of water-ice and aqueous precipitates on Mars, we propose that a number of the erosive features identified in Inca City, among them spiders, result from the seasonal melting of aqueous salty solutions.     

Chemical mapping of proterozoic organic matter at submicron spatial resolution

A NanoSIMS ion microprobe was used to map the submicron-scale distributions of carbon, nitrogen, sulfur, silicon, and oxygen in organic microfossils and laminae in a thin section of the approximately 0.85 billion year old Bitter Springs Formation of Australia. The data provide clues about the original chemistry of the microfossils, the silicification process, and the biosignatures of specific microorganisms and microbial communities. Chemical maps of fossil unicells and filaments revealed distinct wall- and sheath-like structures enriched in C, N, and S, consistent with their accepted biological origin. Surprisingly, organic laminae, previously considered to be amorphous, also exhibited filamentous and apparently compressed spheroidal structures defined by strong enrichments in C, N, and S. By analogy to NanoSIMS data from the well-preserved microfossils, these structures were interpreted as being of biological origin, most likely representing densely packed remnants of microbial mats. Given that the preponderance of organic matter in Precambrian sediments is similarly "amorphous," our findings indicate that a re-evaluation of ancient specimens via in situ structural, chemical, and isotopic study is warranted. Our analyses have led us to propose new criteria for assessing the biogenicity of problematic kerogenous materials, and, thus, these criteria can be applied to assessments of poorly preserved or fragmentary organic residues in early Archean sediments and any that might occur in meteorites or other extraterrestrial samples.     

The Solar Origin of Corotating Interaction Regions and Their Formation in the Inner Heliosphere

Corotating Interaction Regions (CIRs) form as a consequence of the compression of the solar wind at the interface between fast speed streams and slow streams. Dynamic interaction of solar wind streams is a general feature of the heliospheric medium; when the sources of the solar wind streams are relatively stable, the interaction regions form a pattern which corotates with the Sun. The regions of origin of the high speed solar wind streams have been clearly identified as the coronal holes with their open magnetic field structures. The origin of the slow speed solar wind is less clear; slow streams may well originate from a range of coronal configurations adjacent to, or above magnetically closed structures. This article addresses the coronal origin of the stable pattern of solar wind streams which leads to the formation of CIRs. In particular, coronal models based on photospheric measurements are reviewed; we also examine the observations of kinematic and compositional solar wind features at 1 AU, their appearance in the stream interfaces (SIs) of CIRs, and their relationship to the structure of the solar surface and the inner corona; finally we summarise the Helios observations in the inner heliosphere of CIRs and their precursors to give a link between the optical observations on their solar origin and the in-situ plasma observations at 1 AU after their formation. The most important question that remains to be answered concerning the solar origin of CIRs is related to the origin and morphology of the slow solar wind. This revised version was published online in August 2006 with corrections to the Cover Date.