Electromagnetic containerless undercooling facility and experiments for the shuttle

An electromagnetic furnace is being prepared for flights aboard the space shuttle. This apparatus is capable of melting metals and alloys up to 1400°C melting point by induction heating with subsequent solidification of the freely levitated melt without contact with any container. The solidification can be carried out with greatly reduced fields resulting in minimal heating and stirring of the free melt. Sequential specimens can be processed during flight. Several experiments are planned for a series of flights, beginning in 1985 with an undercooling experiment on NiSn alloys. These will be interspersed with detailed studies of fluid flow caused by low and high field levels in order to quantify the corresponding effect upon the solidification process.     

United Nations International Conference on Space-based Technologies for Disaster Management Held in Beijing

The United Nations International Conference on Space-based Technologies for Disaster Management, "Risk Assessment in the Context of Global Climate Change", was held in Beijing during November 7-9, 2012. The conference was co-organized by the United Nations Office for Outer Space Affairs (UNOOSA) and the Ministry of Civil affairs (MCA) of the People’s Republic of China, in collaboration with the Ministry of Foreign Affairs of PRC, China National Space Administration (CNSA),     

The Information Content of Synthetic Aperture Radar Images of Terrain

A statistical model is developed that portrays an imaging radar as a noisy communication channel with multiplicative noise, and the model is used to evaluate the average amount of information that can be extracted about a target from its radar image. The average information content is also used to define a measure of radiometric resolution for radar images. It is shown that the information content and the resolution capabilities of an imaging radar reach a limit beyond which an increase in scene dynamic range does not improve the information content or the resolution. This limitation results from the multiplicative nature of the noise introduced in the imaging process.     

A Data Compression Technique for Synthetic Aperture Radar Images

A data compression technique is developed for synthetic aperture radar (SAR) imagery. The technique is based on an SAR image model and is designed to preserve the local statistics in the image by an adaptive variable rate modification of block truncation coding (BTC). A data rate of approximately 1.6 bit/pixel is achieved with the technique while maintaining the image quality and cultural (pointlike) targets. The algorithm requires no large data storage and is computationally simple.     

Bomb damage assessment using a dispensed sensor projectile

The problem of obtaining images of a target site after munition impact is approached by releasing a small projectile equipped with a camera from a dropped munition. A ballute is deployed from the sensor projectile shortly after release from the munition. This type of system is capable of viewing munition impact and subsequent target effects over a wide variety of conditions and offers the possibility of real-time battle damage assessment (BDA). However, fundamental limits exist on the duration that the camera is able to view the target after impact for a particular required separation distance between the sensor projectile and the target at impact and the field of regard (FOR) of the camera. Munition release altitude and velocity significantly affect these fundamental limits. Optimal performance is attained under high altitude and low speed munition drop conditions. Basic characteristics of the camera projectile also significantly influence system performance. Maximum target view time is attained with a low weight high drag configuration., To reduce the maximum acceleration experienced by the sensor projectile, a small delay time between the release of the small sensor projectile from the munition and inflation of ballute is required.     

The Gas Chromatograph Mass Spectrometer for the Huygens Probe

The Gas Chromatograph Mass Spectrometer (GCMS) on the Huygens Probe will measure the chemical composition of Titan's atmosphere from 170 km altitude (∼1 hPa) to the surface (∼1500 hPa) and determine the isotope ratios of the major gaseous constituents. The GCMS will also analyze gas samples from the Aerosol Collector Pyrolyser (ACP) and may be able to investigate the composition (including isotope ratios) of several candidate surface materials. The GCMS is a quadrupole mass filter with a secondary electron multiplier detection system and a gas sampling system providing continuous direct atmospheric composition measurements and batch sampling through three gas chromatographic (GC) columns. The mass spectrometer employs five ion sources sequentially feeding the mass analyzer. Three ion sources serve as detectors for the GC columns and two are dedicated to direct atmosphere sampling and ACP gas sampling respectively. The instrument is also equipped with a chemical scrubber cell for noble gas analysis and a sample enrichment cell for selective measurement of high boiling point carbon containing constituents. The mass range is 2 to 141 Dalton and the nominal detection threshold is at a mixing ratio of 10^{− 8}. The data rate available from the Probe system is 885 bit/s. The weight of the instrument is 17.3 kg and the energy required for warm up and 150 minutes of operation is 110 Watt-hours. This revised version was published online in August 2006 with corrections to the Cover Date.     

The Skylab sleep monitoring experiment: methodology and initial results

The sleep monitoring experiment permitted an objective evaluation of sleep characteristics during the first two manned Skylab flights. Hardware located onboard the spacecraft accomplished data acquisition, analysis, and preservation, thereby permitting near-real-time evaluation of sleep during the flights and more detailed postmission analysis. The crewman studied during the 28-Day Mission showed some decrease in total sleep time an increase in the percentage of Stage 4 sleep, while the subject in the 59-Day Mission exhibited little change in total sleep time and a small decrease in Stage 4 and REM sleep. Some disruption of sleep characteristics was seen in the final days of both missions, and both subjects exhibited decreases in REM-onset latency in the immediate postflight period. The relatively minor changes seen were not of the type nor magnitude which might be expected to be associated with significant degradation of performance capability.