ROSA Rotorcraft Open Systems Avionics

Commercial standards adopted from the volume-driven electronics markets provide improved processing capacities over those widely used military standards and at reduced cost. Desired future capabilities and advanced functions, such as RPA, require the throughput, bandwidth, and memory provided by commercial processors and data buses. The primary issues needing resolution prior to implementation are related to operations in military rotorcraft environment, reliability, redundancy management, and fault and battle damage tolerance. In addition, some required network components presently do not exist in the preferred form factors. The ROSA project is providing effective laboratory demonstrations of COTS products and open systems specifications and standards to rotorcraft avionics. Preliminary cost estimates forecast large potential savings and create a compelling business case for follow-on research and transition to production systems. In addition, the project is developing a Rotorcraft Technical Architecture with the participation of many industry partners and will promote the resulting documentation as background materials for the JTA-A     

Fluctuating Target Detection in Clutter Using Sidelobe Blanking Logic

In an earlier paper, Maisel [6] considered two-channel detection systems using a sidelobe blanking logic when a nonfluctuating target was present. This paper is an extension of the earlier work to include fluctuating targets. The Swerling I, II, III, and IV models are considered when single-pulse detection is of interest. An adaptive threshold procedure is also briefly discussed whereby the probability of false alarm at any given resolution cell is maintained constant, even though the input clutter level may vary from cell to cell or from beam position to beam position. Useful data are presented for detection probabilities in the range 0.5 to 0.9, for false alarm probabilities in the range 104 to 10-8, and for a false detection probability of 0.1 for a sidelobe target yielding an apparent signal to total noise power density ratio of 13.0 dB in the main beam receiver.     

Elliptical Error Statistics for Radiolocation Analysis

A review is made of current techniques used in the statistical analysis of radio direction finding data which predict a region of probable transmitter location based upon a collection of intersecting lines of bearing measurements. This region has been conventionally defined by the elliptical error probability (EEP). Two characterizations for EEP are considered, and a technique is proposed for robust estimation of the elliptical region of probable location.     

Needs in space education for the 21st century

There is increasingly broad concern in the USA today about the quality, vibrancy and appeal of science and technical education in general and space education in particular. There needs to be a robust link between the educational community (i.e. the primary and secondary schools as well as colleges and universities) and a well-defined space research and exploration agenda that is strongly supported by the space industry, NASA and other relevant US governmental agencies. Without such a renewal of mission and new goals it will be difficult to re-invigorate and expand quality space education programs. A workshop was therefore convened in 2003 to analyze the problem, discuss new initiatives, organize a survey inviting suggestions from a range of relevant players and draw conclusions on what the USA needs to do to improve space education in the 21st century. Although the focus of this workshop was on space education in the USA the international dimensions of this problem were also addressed and the firm conclusion was reached that similar issues and concerns apply in Europe, Canada, Japan and other spacefaring nations. This article is an edited version of a White Paper subsequently produced to highlight the problem, summarize the proceedings of the workshop and present the results of the survey. Greater clarity in the definition of national space goals, the upgrading of teachers’ skills and an increase in technical scholarships are among the steps recommended.     

Atmospheric Escape and Evolution of Terrestrial Planets and Satellites

The origin and evolution of Venus’, Earth’s, Mars’ and Titan’s atmospheres are discussed from the time when the active young Sun arrived at the Zero-Age-Main-Sequence. We show that the high EUV flux of the young Sun, depending on the thermospheric composition, the amount of IR-coolers and the mass and size of the planet, could have been responsible that hydrostatic equilibrium was not always maintained and hydrodynamic flow and expansion of the upper atmosphere resulting in adiabatic cooling of the exobase temperature could develop. Furthermore, thermal and various nonthermal atmospheric escape processes influenced the evolution and isotope fractionation of the atmospheres and water inventories of the terrestrial planets and Saturn’s large satellite Titan efficiently.     

The Ultraviolet Spectrograph on NASA’s Juno Mission

The ultraviolet spectrograph instrument on the Juno mission (Juno-UVS) is a long-slit imaging spectrograph designed to observe and characterize Jupiter’s far-ultraviolet (FUV) auroral emissions. These observations will be coordinated and correlated with those from Juno’s other remote sensing instruments and used to place in situ measurements made by Juno’s particles and fields instruments into a global context, relating the local data with events occurring in more distant regions of Jupiter’s magnetosphere. Juno-UVS is based on a series of imaging FUV spectrographs currently in flight—the two Alice instruments on the Rosetta and New Horizons missions, and the Lyman Alpha Mapping Project on the Lunar Reconnaissance Orbiter mission. However, Juno-UVS has several important modifications, including (1) a scan mirror (for targeting specific auroral features), (2) extensive shielding (for mitigation of electronics and data quality degradation by energetic particles), and (3) a cross delay line microchannel plate detector (for both faster photon counting and improved spatial resolution). This paper describes the science objectives, design, and initial performance of the Juno-UVS.     

Radar: The Cassini Titan Radar Mapper

The Cassini RADAR instrument is a multimode 13.8 GHz multiple-beam sensor that can operate as a synthetic-aperture radar (SAR) imager, altimeter, scatterometer, and radiometer. The principal objective of the RADAR is to map the surface of Titan. This will be done in the imaging, scatterometer, and radiometer modes. The RADAR altimeter data will provide information on relative elevations in selected areas. Surfaces of the Saturn’s icy satellites will be explored utilizing the RADAR radiometer and scatterometer modes. Saturn’s atmosphere and rings will be probed in the radiometer mode only. The instrument is a joint development by JPL/NASA and ASI. The RADAR design features significant autonomy and data compression capabilities. It is expected that the instrument will detect surfaces with backscatter coefficient as low as −40 dB.RADAR Team LeaderThis revised version was published online in July 2005 with a corrected cover date.     

The Solar Wind Around Pluto (SWAP) Instrument Aboard New Horizons

The Solar Wind Around Pluto (SWAP) instrument on New Horizons will measure the interaction between the solar wind and ions created by atmospheric loss from Pluto. These measurements provide a characterization of the total loss rate and allow us to examine the complex plasma interactions at Pluto for the first time. Constrained to fit within minimal resources, SWAP is optimized to make plasma-ion measurements at all rotation angles as the New Horizons spacecraft scans to image Pluto and Charon during the flyby. To meet these unique requirements, we combined a cylindrically symmetric retarding potential analyzer with small deflectors, a top-hat analyzer, and a redundant/coincidence detection scheme. This configuration allows for highly sensitive measurements and a controllable energy passband at all scan angles of the spacecraft.     

Virus protein assembly in microgravity.

The coat of polyomavirus is composed of three proteins that can self-assemble to form an icosahedral capsid. VP1 represents 75% of the virus capsid protein and the VP1 capsomere subunits are capable of self assembly to form a capsid-like structure. Ground-based and orbiter studies were conducted with VP1 protein cloned in an expression vector and purified to provide ample quantities for capsomere-capsid assembly. Flight studies were conducted on STS-37 on April 5-9, 1991. Assembly initiated when a VP1 protein solution was interfaced with a Ca+2 buffer solution (pH 5.0). After four days a second alignment terminated the assembly process and allowed for glutaraldehyde fixation. Flight and ground-based samples were analyzed by electron microscopy. Ground-based experiments revealed the assembly of VP1 into capsid-like structures and a heterogenous size array of capsomere subunits. Samples reacted in microgravity, however, showed capsomeres of a homogenous size, but lack of capsid-like assembly.