Book reviews

Space Science Reviews -     

Integrated design systems — capturing, reusing and optimizing design methods in new millennium

An important goal of New Millennium is to research new methods of performing spacecraft and mission design. We have completed the first phase of our effort on how to make design tools such as analysis programs more available. We are now embarking with Stanford University on discovering methods to allow more project history and knowledge to be automatically captured and reused and with Ames Research Center on how to use virtual reality to enhance the visualization of new missions before any hardware exists. We are also trying to capture the design process in an electronic form so that computer aided optimization may lead to a vastly greater search of the possible designs which meet the design requirements.     

Advantages of using subsurface flow constructed wetlands for wastewater treatment in space applications: ground-based Mars Base prototype.

Research and design of subsurface flow wetland wastewater treatment systems for a ground-based experimental prototype Mars Base facility has been carried out, using a subsurface flow approach. These systems have distinct advantages in planetary exploration scenarios: they are odorless, relatively low-labor and low-energy, assist in purification of water and recycling of atmospheric CO2, and will support some food crops. An area of 6-8 m2 may be sufficient for integration of wetland wastewater treatment with a prototype Mars Base supporting 4-5 people. Discharge water from the wetland system will be used as irrigation water for the agricultural crop area, thus ensuring complete recycling and utilization of nutrients. Since the primary requirements for wetland treatment systems are warm temperatures and lighting, such bioregenerative systems may be integrated into early Mars base habitats, since waste heat from the lights may be used for temperature maintenance in the human living environment. "Wastewater gardens (TM)" can be modified for space habitats to lower space and mass requirements. Many of its construction requirements can eventually be met with use of in-situ materials, such as gravel from the Mars surface. Because the technology requires little machinery and no chemicals, and relies more on natural ecological mechanisms (microbial and plant metabolism), maintenance requirements are minimized, and systems can be expected to have long operating lifetimes. Research needs include suitability of Martian soil and gravel for wetland systems, system sealing and liner options in a Mars Base, and wetland water quality efficiency under varying temperature and light regimes.     

Recent experience with different methods of drag prediction

During the recent past the process of engineering design has changed entirely because of rapid developments in computational simulations. In aerodynamic design, computational fluid dynamics (CFD) methods are slowly superseding empirical methods and design engineers are spending more and more time applying CFD tools to analyze and predict the aerodynamic characteristics of vehicles. The purpose of this paper is to review recent experiences in CFD-based drag prediction with an emphasis on flow solutions governed by the Euler and Reynolds-averaged Navier–Stokes equations. For these types of flow solutions, various drag analysis methodologies are outlined and applied to determine the drag of components of as well as whole-body airplanes, helicopters, and ground-based vehicles at subsonic and transonic flow conditions. The review demonstrates that although significant progress has been made, CFD-based drag prediction still faces a number of hurdles that must be dealt with before it will become more widely accepted.     

The local neutron flux at low earth-orbiting altitudes

The COMPTEL instrument onboard the Compton Gamma Ray Observatory (CGRO) has been used to measure the variation of the atmospheric neutron flux below 5 MeV as a function of vertical cutoff rigidity and spacecraft orientation at an altitude of 450 km. The instrumental 2.2 MeV background line, resulting from thermal neutron capture on hydrogen, was used for the measurement. The dependence of the 2.2 MeV rate on rigidity and geocentre zenith can be described by an analytic function: the line rate decreases linearly with geocentre zenith, and decreases exponentially with the vertical cutoff rigidity. The flux varies on average by about a factor of 3.7 between the extremes in rigidity, and by a factor of 1.7 between the extremes of spacecraft orientation with respect to the Earth. We believe that mass shielding is more important in attenuating the atmospheric albedo than as a source of secondary neutrons. The COMF'TEL instrument is well suited for a long-duration study of the dependence of the neutron flux on the vertical cutoff rigidity and the solar cycle.     

The Marsquake Service: Securing Daily Analysis of SEIS Data and Building the Martian Seismicity Catalogue for InSight

Space Science Reviews - In recent decades, volcanic and cryovolcanic activity on moons within the Solar System has been recognised as an important source of cosmic dust. Two moons, Jupiter’s...     

Analyzing the multilevel structure of the European airport network

The multilayered structure of the European airport network (EAN), composed of con-nections and flights between European cities, is analyzed through the k-core decomposition of the connections network. This decomposition allows to identify the core, bridge and periphery lay-ers of the EAN. The core layer includes the best-connected cities, which include important business air traffic destinations. The periphery layer includes cities with lesser connections, which serve low populated areas where air travel is an economic alternative. The remaining cities form the bridge of the EAN, including important leisure travel origins and destinations. The multilayered structure of the EAN affects network robustness, as the EAN is more robust to isolation of nodes of the core, than to the isolation of a combination of core and bridge nodes.     

Selection and hydroponic growth of potato cultivars for bioregenerative life support systems

As part of the ESA-funded MELiSSA program, Ghent University and the Université catholique de Louvain investigated the suitability, growth and development of four potato cultivars in hydroponic culture under controlled conditions with the aim to incorporate such cultivation system in an Environmental Control and Life Support System (ECLSS). Potato plants can fulfill three major functions in an ECLSS in space missions: (a) fixation of CO₂ and production of O₂, (b) production of tubers for human nutrition and (c) production of clean water after condensation of the water vapor released from the plants by transpiration. Four cultivars (Annabelle, Bintje, Desiree and Innovator) were selected and grown hydroponically in nutrient film technique (NFT) gullies in a growth chamber under controlled conditions. The plant growth parameters, tuber harvest parameters and results of tuber nutritional analysis of the four cultivars were compared. The four potato cultivars grew well and all produced tubers. The growth period lasted 127 days for all cultivars except for Desiree which needed 145 days. Annabelle (1.45 kg/m²) and Bintje (1.355 kg/m²) were the best performing of the four cultivars. They also produced two times more tubers than Desiree and Innovator. Innovator produced the biggest tubers (20.95 g/tuber) and Desiree the smallest (7.67 g/tuber). The size of Annabelle and Bintje potatoes were intermediate. Bintje plants produced the highest total biomass in term of DW. The highest non-edible biomass was produced by Desiree, which showed both the highest shoot and root DW. The manual length and width measurements were also used to predict the total tuber mass. The energy values of the tubers remained in the range of the 2010 USDA and Souci-Fachmann-Kraut food composition databases. The amount of Ca determined was slightly reduced compared to the USDA value, but close to the Souci-Fachmann-Kraut value. The concentration of Cu, Zn and P were high compared to both databases.     

Evidence for the lowering of the centroid of daytime thermospheric O(D) 630.0 nm emission over the magnetic equator: First results

It is shown in this paper for the first time that the intensity of the daytime thermospheric O(¹D) 630.0 nm airglow as measured by the ground-based dayglow photometer over Trivandrum (8.5°N; 77°E; dip lat. 0.5°N), a geomagnetic dip equatorial station, exhibit a direct correlation with the electron density at 180 km. This altitude is about ∼40 km lower than the believed centroid of the O(¹D) 630.0 nm dayglow emission i.e. 220 km. This observation is contrary to the understanding of the behavior of O(¹D) 630.0 nm dayglow over equatorial/low latitudes. Over these latitudes, the variations of the measured intensity of O(¹D) 630.0 nm dayglow are known to be associated with the changes in the electron density at altitudes around 220 km, the centroid of this emission. In this context, the present results indicating the lowering of the peak altitude of O(¹D) 630.0 nm emission from ∼220 to ∼180 km over the dip equator is new. Recent results on solar XUV flux indicate that this could be an important parameter that controls the O(¹D) 630.0 nm dayglow excitation rates through modulations in the neutral and ionic composition in lower thermosphere-ionosphere region. However, the lowering of the centroid of O(¹D) 630.0 nm emission, as shown in this study, has been ascribed primarily to the fountain effect associated with the equatorial ionization anomaly.