European perspectives on trends in public sector Earth observation data policies

The growing number of Earth observation satellites are producing ever increasing amounts of data. These data sets require adequate management to be widely exploited and to ensure preservation of what is a valuable information resource. Many Earth observation organisations have formulated or are developing policies related to how data are managed and distributed which encompass issues such as property rights, access and price of the data, exclusive data use and data archiving. European Earth observation is gaining more prominence in these developing policy issues. This paper is a review, from a largely European perspective, of current Earth observation data policies in operation by various public sector international, regional and national organisations in both the data providing and data user sectors. It will be demonstrated that certain trends exist between the various data policies but that differences in position are present in some key areas which may need to be reconciled in order for the Earth observation sector to reach maturity.     

Sample acquisition, processing and handling systems for future Mars missions

The next generation of Mars exploration robotics will have equipment to acquire subsurface samples, process and refine them, and transfer them to science instruments for observation. In 2003, MD Robotics and NORCAT, under contract with the Canadian Space Agency, designed, developed and tested building block technologies for a sample acquisition, processing and handling system for a future Mars mission. Four key technologies were developed to support this system: drill bit development for varied substrates, sample acquisition mechanisms to acquire cores at depth, material transport technologies to move waste material up the hole, and sample reduction technologies, studying the means to efficiently reduce samples into uniform particle sizes. This paper will discuss the technology development, the driving requirements and the test results.     

A novel pulse TOA analysis technique for radar identification

A new processing technique is presented for identifying individual pulse trains in a buffer load of pulse time-of-arrival (TOA) data from radar warning receiver sets currently in use for electronic warfare (EW). The method is based on the numerical characteristics of the matrix of the differences of the TOA data points. In particular, for a uniform pulse repetition interval (PRI) emitter, this matrix is a symmetrical harmonic Toeplitz matrix the inverse of which has banded tridiagonal form. This form leads to an estimator for the PRI in terms of the trace of the inverted matrix     

Viscoelastic characterization of polymers for deployable composite booms

Deployable space structures are being built from thin-walled fiber-reinforced polymer composite materials due to their high specific strength, high specific stiffness, and designed bistability. However, the inherent viscoelastic behavior of the resin matrix can cause dimensional instability when the composite is stored under strain. The extended time of stowage between assembly and deployment in space can result in performance degradation and in the worst case, mission failure. In this study, the viscoelastic properties of candidate commercial polymers consisting of difunctional and tetrafunctional epoxies and thermoplastic and thermosetting polyimides were evaluated for deployable boom structures of solar sails. Stress relaxation master curves of the candidate polymers were used to predict the relaxation that would occur in 1 year at room temperature under relatively low strains of about 0.1%. A bismaleimide (BMI) showed less stress relaxation (about 20%) than the baseline novolac epoxy (about 50%). Carbon fiber composites fabricated with the BMI resin showed a 44% improvement in resistance to relaxation compared to the baseline epoxy composite.     

Michelson Interferometer for Global High-Resolution Thermospheric Imaging (MIGHTI): Instrument Design and Calibration

The Michelson Interferometer for Global High-resolution Thermospheric Imaging (MIGHTI) instrument was built for launch and operation on the NASA Ionospheric Connection Explorer (ICON) mission. The instrument was designed to measure thermospheric horizontal wind velocity profiles and thermospheric temperature in altitude regions between 90 km and 300 km, during day and night. For the wind measurements it uses two perpendicular fields of view pointed at the Earth’s limb, observing the Doppler shift of the atomic oxygen red and green lines at 630.0 nm and 557.7 nm wavelength. The wavelength shift is measured using field-widened, temperature compensated Doppler Asymmetric Spatial Heterodyne (DASH) spectrometers, employing low order échelle gratings operating at two different orders for the different atmospheric lines. The temperature measurement is accomplished by a multichannel photometric measurement of the spectral shape of the molecular oxygen A-band around 762 nm wavelength. For each field of view, the signals of the two oxygen lines and the A-band are detected on different regions of a single, cooled, frame transfer charge coupled device (CCD) detector. On-board calibration sources are used to periodically quantify thermal drifts, simultaneously with observing the atmosphere. The MIGHTI requirements, the resulting instrument design and the calibration are described.     

The socioeconomic benefits of Earth science and applications research: reducing the risks and costs of natural disasters in the USA

A wealth of satellite data has provided information on weather and climate phenomena for the past 40 years. Within this period, however, the heavy human and economic costs of natural disasters have increased considerably. Using hurricanes, droughts, floods and earthquakes which occurred in the USA as examples, this article describes how Earth science can be applied to such situations to predict or mitigate their effects. The economic value of providing such information is discussed, as are the issues that can affect how successful its provision will be.     

Continuity of moderate resolution Earth observation data: is an international solution the answer?

The operation of the US Landsat-7, launched in 1999, has proved a marked success. Together with the earlier Landsat data stored at the US Geological Survey Earth Data Analysis Center and other centers around the world, Landsat 7 data constitute a powerful tool for analyzing changes in the Earth's surface. However, the continuity of the Landsat system is not assured. An international system in which other countries participate could provide a more robust system, while spreading the costs and benefits of supplying such data more broadly. This paper explores the potential for creating an international arrangement to supply data of moderate resolution and extensive coverage in order to contribute to planetary stewardship, and discusses several different implementation approaches.     

Use of sunlight for plant lighting in a bioregenerative life support system – Equivalent system mass calculations

Plant lighting is a critical issue for cost effectiveness of bioregenerative systems. A plant lighting system using sunlight has been investigated and compared to systems using electrical lighting. Co-generation of electricity and use of in situ resource utilization (ISRU) were also considered. The fixed part of equivalent system mass was found to be reduced by factors of from 3.1 to 3.9, according to the mission assumptions. The time-dependent part of equivalent system mass was reduced by a smaller value, of about 1.05. Cost effectiveness of bioregeneration has been compared to the cost of shipping food. Break-even times for different Lunar and Mars missions were generally in the order of 2–10 years, and were quite sensitive to the assumptions. There is significant scope for future refinement of these values, and work is ongoing.