Isotopes of Volatiles in Pre-Solar Grains

Elements usually considered volatile are key constituents (C, N, O) of the pre-solar grains identified in primitive meteorites and/or key diagnostic elements (noble gases). Their isotopic compositions generally are unlike anything seen in matter of solar-system origin. The large variations are indicative of the various stellar sources and various processes of nucleosynthesis by which they were created. This revised version was published online in August 2006 with corrections to the Cover Date.     

Obscured Activity: AGN, Quasars, Starbursts and ULIGs Observed by the Infrared Space Observatory

Some of the most ‘active’ galaxies in the Universe are obscured by large quantities of dust and emit a substantial fraction of their bolometric luminosity in the infrared. Observations of these infrared luminous galaxies with the Infrared Space Observatory (ISO) have provided a relatively unabsorbed view to the sources fuelling this active emission. The improved sensitivity, spatial resolution and spectroscopic capability of ISO over its predecessor Infrared Astronomical Satellite (IRAS) of enabled significant advances in the understanding of the infrared properties of active galaxies. ISO surveyed a wide range of active galaxies which, in the context of this review, includes those powered by intense bursts of star formation as well as those containing a dominant active galactic nucleus (AGN). Mid-infrared imaging resolved for the first time the dust enshrouded nuclei in many nearby galaxies, while a new era in infrared spectroscopy was opened by probing a wealth of atomic, ionic and molecular lines as well as broad band features in the mid- and far-infrared. This was particularly useful, since it resulted in the understanding of the power production, excitation and fuelling mechanisms in the nuclei of active galaxies including the intriguing but so far elusive ultraluminous infrared galaxies. Detailed studies of various classes of AGN and quasars greatly improved our understanding of the unification scenario. Far-infrared imaging and photometry revealed the presence of a new very cold dust component in galaxies and furthered our knowledge of the far-infrared properties of faint starbursts, ULIGs and quasars. We summarise almost nine years of key results based on ISO data spanning the full range of luminosity and type of active galaxies.     

Characterization and Calibration of the CheMin Mineralogical Instrument on Mars Science Laboratory

A principal goal of the Mars Science Laboratory (MSL) rover Curiosity is to identify and characterize past habitable environments on Mars. Determination of the mineralogical and chemical composition of Martian rocks and soils constrains their formation and alteration pathways, providing information on climate and habitability through time. The CheMin X-ray diffraction (XRD) and X-ray fluorescence (XRF) instrument on MSL will return accurate mineralogical identifications and quantitative phase abundances for scooped soil samples and drilled rock powders collected at Gale Crater during Curiosity’s 1-Mars-year nominal mission. The instrument has a Co X-ray source and a cooled charge-coupled device (CCD) detector arranged in transmission geometry with the sample. CheMin’s angular range of 5^° to 50^° 2θ with <0.35^° 2θ resolution is sufficient to identify and quantify virtually all minerals. CheMin’s XRF requirement was descoped for technical and budgetary reasons. However, X-ray energy discrimination is still required to separate Co?Kα from Co?Kβ and Fe?Kα photons. The X-ray energy-dispersive histograms (EDH) returned along with XRD for instrument evaluation should be useful in identifying elements Z>13 that are contained in the sample. The CheMin XRD is equipped with internal chemical and mineralogical standards and 27 reusable sample cells with either Mylar^? or Kapton^? windows to accommodate acidic-to-basic environmental conditions. The CheMin flight model (FM) instrument will be calibrated utilizing analyses of common samples against a demonstration-model (DM) instrument and CheMin-like laboratory instruments. The samples include phyllosilicate and sulfate minerals that are expected at Gale crater on the basis of remote sensing observations.     

Quantitative Assessments of the Martian Hydrosphere

In this paper, we review current estimates of the global water inventory of Mars, potential loss mechanisms, the thermophysical characteristics of the different reservoirs that water may be currently stored in, and assess how the planet’s hydrosphere and cryosphere evolved with time. First, we summarize the water inventory quantified from geological analyses of surface features related to both liquid water erosion, and ice-related landscapes. They indicate that, throughout most of Martian geologic history (and possibly continuing through to the present day), water was present to substantial depths, with a total inventory ranging from several 100 to as much as 1000 m Global Equivalent Layer (GEL). We then review the most recent estimates of water content based on subsurface detection by orbital and landed instruments, including deep penetrating radars such as SHARAD and MARSIS. We show that the total amount of water measured so far is about 30 m GEL, although a far larger amount of water may be stored below the sounding depths of currently operational instruments. Finally, a global picture of the current state of the subsurface water reservoirs and their evolution is discussed.     

Oxygen line mapping of SN 1006 with Suzaku

SN 1006 is one of the supernova remnants (SNRs) with relatively low-temperature electrons, considering the young age of just 1000 years. We carried out SN 1006 mapping observations with the X-ray Imaging Spectrometers (XIS) and the Hard X-ray Detector (HXD) onboard Suzaku, the fifth Japanese X-ray satellite. Thanks to the excellent spectral resolution of XIS in the soft X-ray band, H-like and He-like oxygen emission lines were clearly detected, and we could make a map of the line intensity, and as well as a flux and the photon index of nonthermal component. We found that these parameters have spatial dependences from region to region in the SNR; the north region is bright in nonthermal, while dim in thermal; the east region is bright in both nonthermal and thermal; the inner region shows dim nonthermal and bright thermal emission. The photon index is the smallest in the north region.     

SCIAMACHY limb measurements of NO2, BrO and OClO. Retrieval of vertical profiles: Algorithm,first results,sensitivity and comparison studies

The Scanning Imaging Absorption Spectrometer for Atmospheric Chartography (SCIAMACHY) measures scattered sun light also in limb viewing mode (i.e. tangential to Earth’s surface and its atmosphere), which allows determining vertical profiles of atmospheric trace gases. First results on the retrieval of NO₂, BrO and OClO profiles from the SCIAMACHY Limb measurements are presented and compared to independent satellite and balloon borne observations.     

Power system design of ESMO

The European Student Moon Orbiter (ESMO) spacecraft is a student-built mini satellite being designed for a mission to the Moon. Designing and launching mini satellites are becoming a current trend in the space sector since they provide an economic way to perform innovative scientific experiments and in-flight demonstration of novel space technologies. The generation, storage, control, and distribution of the electrical power in a mini satellite represents unique challenges to the power engineer since the mass and volume restrictions are very stringent. Regardless of these problems, every subsystem and payload equipment must be operated within their specified voltage band whenever they required to be turned on. This paper presents the preliminary design of a lightweight, compact, and reliable power system for ESMO that can generate 720 W. Some of the key components of the EPS include ultra triple-junction (UTJ) GaAs solar cells controlled by maximum power point trackers, and high efficiency Li-ion secondary batteries recharged in parallel.     

BAS—The project of an earth-atmosphere spectrophotometer for basic research

The earth-atmosphere spectrophotometer BAS is intended to be used for basic research in the field of remote sensing. The main advantages of BAS are the possibility of a high-accuracy calibration in absolute units utilizing the extraterrestrial spectral solar energy distribution and its simultaneous use for radiance and for irradiance measurements, e.g. the same spectrophotometer BAS to measure immediately one after the other the high irradiances of the sun (transmission measurement) and very low radiances of water surfaces.Data evaluation will be made immediately by the BAS-linked computer for field measurements.Further important technical parameters of BAS are the scanning of the spectral range 0.38 to 1.12 μm in 40 steps within 3 s, low mass of about 4 kg, power supply by rechargeable battery pack. BAS is also suited for measurements to be made from airborne and shipborne platforms.Different applications are shown by some examples.     

CASH 2021: commercial access and space habitation

Issues about commercialization of space have been a growing concern in the past decade for the space community. This paper focuses on the work from a team of 51 students attending the Summer Session Program of the International Space University in Bremen, Germany. CASH 2021 (Commercial Access and Space Habitation) documents a plan that identifies commercial opportunities for space utilization that will extend human presence in space, and will chart the way forward for the next 20 years. The group selected four commercial sectors that show the most promise for the future: tourism, entertainment, space system service, assembly and debris removal, and research and development/production. The content of this document presents the results of their research. Historical activities in each of the commercial sectors are reviewed along with the current market situation. To provide a coherent background for future commercialization possibilities a scenario has been developed. This scenario includes a postulated upon ideal future and includes social, political and economic factors that may affect the space industry over the timeline of the study. The study also presents a roadmap, within the limited optimistic scenario developed, for the successful commercialization of space leading to future human presence in space. A broad range of commercially viable opportunities, not only within the current limits of the International Space Station, but also among the many new developments that are expected by 2021 are discussed.