North Korea''s first satellite: fact and fiction

On 4 September 1998 North Korea announced that it had launched its first satellite on 31 August. Whilst the North Koreans maintained that they had a satellite in orbit, nothing was tracked in the West. This paper presents a review of what the North Koreans announced concerning the satellite launch and the various statements and claims which were made by both the Russians and the USA before the question of the launch being successful or unsuccessful was finally resolved.     

Science in the national vision for space exploration: objectives and constituencies of the ‘discovery-driven’ paradigm

The NASA/White House Vision for Space Exploration is primarily focused on the development of human and robotic systems that will enable ‘discovery-driven’ investigations in areas important to the scientific community: Mars, the solar system's outer moons, and planets orbiting other stars. Such a portfolio can only be realized if NASA is prepared to target investment at opportunities that are most scientifically compelling. NASA's leaders will have to make decisions in subjective and uncertain environments about the relative long-term value of different kinds of scientific discoveries seen as equally important to different groups. A management paradigm of this kind will imply assessment of heterogeneous priorities and management of interdependent and changing requirements. In order to identify the basis and implications of a ‘discovery-driven’ paradigm, this paper surveys the relationship between the Vision's principles and its programmatic content, the objectives of the Vision's scientific focus areas and their interrelationships, and the public context in which science-focused exploration will proceed.     

A root moisture sensor for plants in microgravity.

Development of components for bioregenerative life-support systems is a vital step toward long-term space exploration. The culturing of plants in a microgravity environment may be optimized by the use of appropriate sensors and controllers. This paper describes a sensor developed for determining the amount of fluid (nutrient solution) available on the surface of a porous ceramic nutrient delivery substrate to the roots of conventional crop plants. The sensor is based on the change in thermal capacitance and thermal conductance near the surface as the moisture content changes. The sensor could be employed as a data acquisition and control sensor to support the automated monitoring of plants grown in a microgravity environment.     

Energy storage at 77 K in multilayer ceramic capacitors

A ceramic material having a large dielectric constant at 77 K, ε=8000-12000, has been developed for capacitive energy storage at this temperature. A large matrix of multilayer ceramic capacitors were fabricated using conventional tape-casting methods to optimize the dielectric breakdown strength at 77 K, and measured energy storage values on these capacitors range up to 6 J/cm³ at 77 K. An unfused bank of these capacitors was voltage-cycled 10⁵ times at 77 K without failure, and the heating effects during cycling were immeasurably small (i.e., nitrogen boiloff was monitored). An electrocaloric effect on discharge (ΔT~1 K) contributes to the thermal stability. Measurements of the frequency dependence of the dielectric properties of the ceramic at 77 K indicate a fundamental limit of about 8 μs for the switching repetition rate. Improved capacitor-manufacturing methods are discussed which can increase the energy density to the 20-30 J/cm³ range     

Soviet launch failures reviewed

The USSR has always been reluctant to reveal details of failures in its space programme, and only a few failures have been annouced publically. Some official US sources list failures in the Soviet programme, although these official listings end in mid-1964. The aviation press often reports rumoured failures, and it is the job of an analyst to try and separate the wheat from the chaff.     

Topological biosignatures: large-scale structure of chemical networks from biology and astrochemistry

The chemical basis of life involves more than simply the presence of biological molecules; biochemical systems embody a complex network of reactions with characteristic topological features. At the same time, chemical complexity is also present in nonbiological contexts, inviting us to clarify the relationship between chemistry and life through comparative studies. This study examines chemical networks from biology (the metabolism of E. coli) and astronomy (gas-phase reactions in dark molecular clouds) to establish common topological features that may be generic for any complex chemical system, as well as clear differences that may be topological signatures of life. The biological and astrochemical networks exhibit different scaling behaviors, and the network motifs found in the two systems show similarities as well as significant differences. The PageRank algorithm was used to quantify the degree to which individual species act primarily as products or reactants; in the metabolic network, these two roles are nearly identical for most species, whereas the astrochemical network shows a clearer partitioning into reactants and products.     

Bacterial growth at the high concentrations of magnesium sulfate found in martian soils

The martian surface environment exhibits extremes of salinity, temperature, desiccation, and radiation that would make it difficult for terrestrial microbes to survive. Recent evidence suggests that martian soils contain high concentrations of MgSO? minerals. Through warming of the soils, meltwater derived from subterranean ice-rich regolith may exist for an extended period of time and thus allow the propagation of terrestrial microbes and create significant bioburden at the near surface of Mars. The current report demonstrates that halotolerant bacteria from the Great Salt Plains (GSP) of Oklahoma are capable of growing at high concentrations of MgSO? in the form of 2 M solutions of epsomite. The epsotolerance of isolates in the GSP bacterial collection was determined, with 35% growing at 2 M MgSO?. There was a complex physiological response to mixtures of MgSO? and NaCl coupled with other environmental stressors. Growth also was measured at 1 M concentrations of other magnesium and sulfate salts. The complex responses may be partially explained by the pattern of chaotropicity observed for high-salt solutions as measured by agar gelation temperature. Select isolates could grow at the high salt concentrations and low temperatures found on Mars. Survival during repetitive freeze-thaw or drying-rewetting cycles was used as other measures of potential success on the martian surface. Our results indicate that terrestrial microbes might survive under the high-salt, low-temperature, anaerobic conditions on Mars and present significant potential for forward contamination. Stringent planetary protection requirements are needed for future life-detection missions to Mars.     

Return to Europa: Overview of the Jupiter Europa orbiter mission

Missions to explore Europa have been imagined ever since the Voyager mission first suggested that Europa was geologically very young. Subsequently, the Galileo spacecraft supplied fascinating new insights into this satellite of Jupiter. Now, an international team is proposing a return to the Jupiter system and Europa with the Europa Jupiter System Mission (EJSM). Currently, NASA and ESA are designing two orbiters that would explore the Jovian system and then each would settle into orbit around one of Jupiter’s icy satellites, Europa and Ganymede. In addition, the Japanese Aerospace eXploration Agency (JAXA) is considering a Jupiter magnetospheric orbiter and the Russian Space Agency is investigating a Europa lander.     

Bacterial community in ancient Siberian permafrost as characterized by culture and culture-independent methods

The microbial composition of ancient permafrost sediments from the Kolyma lowland of Northeast Eurasia was examined through culture and culture-independent approaches. These sediments have been continuously frozen for 5,000 to 2-3 million years. A total of 265 Bacteria 16S rRNA gene sequences were amplified from the permafrost total-community genomic DNA and screened by amplified ribosomal 16S rRNA restriction analysis. Members of three major lineages were found: gamma-Proteobacteria (mostly Xanthomonadaceae), Actinobacteria, and Firmicutes. We also determined partial 16S rRNA gene sequences of 49 isolates from a collection of 462 aerobes isolated from these sediments. The bacteria included Actinomycetales (Arthrobacter and Microbacteriaceae); followed by the Firmicutes (Exiguobacterium and Planomicrobium); the Bacteroidetes (Flavobacterium); the gamma-Proteobacteria (Psychrobacter); and the alpha-Proteobacteria (Sphingomonas). Both culture and culture-independent approaches showed the presence of high and low G+C Gram-positive bacteria and gamma-Proteobacteria. Some of the 16S rRNA gene sequences of environmental clones matched those of Arthrobacter isolates. Two-thirds of the isolates grew at -2.5 degrees C, indicating that they are psychroactive, and all are closely related to phylogenetic groups with strains from other cold environments, mostly commonly from Antarctica. The culturable and non-culturable microorganisms found in the terrestrial permafrost provide a prototype for possible life on the cryogenic planets of the Solar System.