The relevance of economic data in the decision-making process for orbital launch vehicle programs, a U.S. perspective

Over the past fifteen years, major U.S. initiatives for the development of new launch vehicles have been remarkably unsuccessful. The list is long: NLI, SLI, and X-33, not to mention several cancelled programs aimed at high speed airplanes (NASP, HSCT) which would share some similar technological problems.The economic aspects of these programs are equally as important to their success as are the technical aspects. In fact, by largely ignoring economic realities in the decisions to undertake these programs and in subsequent management decisions, space agencies (and their commercial partners) have inadvertently contributed to the eventual demise of these efforts.The transportation revolution that was envisaged by the promises of these programs has never occurred. Access to space is still very expensive; reliability of launch vehicles has remained constant over the years; and market demand has been relatively low, volatile and slow to develop. The changing international context of the industry (launching overcapacity, etc.) has also worked against the investment in new vehicles in the U.S. Today, unless there are unforeseen technical breakthroughs, orbital space access is likely to continue as it has been with high costs and market stagnation.Space exploration will require significant launching capabilities. The details of the future needs are not yet well defined. But, the question of the launch costs, the overall demand for vehicles, and the size and type of role that NASA will play in the overall launch market is likely to influence the industry. This paper will emphasize the lessons learned from the economic and management perspective from past launch programs, analyze the issues behind the demand for launches, and project the challenges that NASA will face as only one new customer in a very complex market situation. It will be important for NASA to make launch vehicle decisions based as much on economic considerations as it does on solving new technical challenges.     

Large-scale Bright Fronts in the Solar Corona: A?Review of?��EIT waves��

??EIT waves?? are large-scale coronal bright fronts (CBFs) that were first observed in 195 Å images obtained using the Extreme-ultraviolet Imaging Telescope (EIT) onboard the Solar and Heliospheric Observatory (SOHO). Commonly called ??EIT waves??, CBFs typically appear as diffuse fronts that propagate pseudo-radially across the solar disk at velocities of 100?C700 km?s^?1 with front widths of 50?C100 Mm. As their speed is greater than the quiet coronal sound speed (c _s ??200 km?s^?1) and comparable to the local Alfvén speed (v _A ??1000 km?s^?1), they were initially interpreted as fast-mode magnetoacoustic waves ( $v_{f}=(c_{s}^{2} + v_{A}^{2})^{1/2}$ ). Their propagation is now known to be modified by regions where the magnetosonic sound speed varies, such as active regions and coronal holes, but there is also evidence for stationary CBFs at coronal hole boundaries. The latter has led to the suggestion that they may be a manifestation of a processes such as Joule heating or magnetic reconnection, rather than a wave-related phenomena. While the general morphological and kinematic properties of CBFs and their association with coronal mass ejections have now been well described, there are many questions regarding their excitation and propagation. In particular, the theoretical interpretation of these enigmatic events as magnetohydrodynamic waves or due to changes in magnetic topology remains the topic of much debate.     

Lunar international science coordination/calibration targets (L-ISCT)

Eight lunar areas, each ∼200 km in diameter, are identified as targets for coordinated science and instrument calibration for the orbital missions soon to be flown. Instrument teams from SELENE, Chang’E, Chandrayaan-1, and LRO are encouraged to participate in a coordinated activity of early-release data that will improve calibration and validation of data across independent and diverse instruments. The targets are representative of important lunar terrains and geologic processes and thus will also provide a broad introduction to lunar science for new investigators. We briefly identify additional cross-calibration issues for instruments that produce time series data rather than maps.     

The African Leadership Conference on Space Science and Technology for Sustainable Development

The African Leadership Conference on Space Science and Technology (known as “the ALC”) is a regional conference to promote intra-African cooperation in the uses of space science and technology to support Africa’s development. The first such conference was held in 2005 in Abuja, Nigeria, followed by South Africa (2007), Algeria (2009) and Kenya (2011). The ALC has come to be regarded as a representative African forum in the global space community. This paper provides an overview of the structure and activities of the ALC and presents the highlights and outcomes of the first four conferences and their contribution to shaping the development of the African space arena. The paper concludes with an analysis of the challenges facing the ALC and some proposed measures to enhance its effectiveness.     

Why we need a space elevator

The goals of and vision for development of a space elevator have been discussed repeatedly. However, why we should develop one has been glossed over. This paper will focus upon the major issue—why build a space elevator infrastructure? It considers why we need a space elevator, what missions it would enable and how far it would reduce costs. There is no doubt that some major missions would be enhanced or significantly enabled by a space elevator infrastructure. Global communications, energy, monitoring of the Earth, global/national security, planetary defense, and exploration beyond low-Earth orbit are a few examples. In the end, if we are serious about extending space development and avoiding limitations on the human spirit, the reason we should build a space elevator is because we must!     

Observations of Climate Variability – Discussion Session 3a

Space Science Reviews -     

Biparametric CFAR procedures for lognormal clutter

The authors consider procedures for constant false alarm rate in lognormal clutter, accounting for variations of both the scale and a shape parameter of the clutter. Adaptivity to both parameters is obtained through biparametric estimation based on a sliding window surrounding the radar cell under test. Some procedures exploiting best linear unbiased estimation (BLUE) are presented and compared to a previous procedure called Log-t, which uses maximum likelihood estimation (MLE). The comparison is carried on for both a homogeneous clutter environment and for instances of inhomogeneous environment (clutter edges and spurious targets). In the latter instances, some advantages of BLUE procedures which stem from the opportunity of censoring are highlighted     

Experimental investigations on hull-fin interferences of the LOTTE airship

In the present paper experimental aerodynamic investigations on an airship configuration at angle of attack with special emphasis on the hull-fin region are reported. In particular, visualizations of flow phenomena on both hull and fins are studied. Quantitative measurements of the integral force and moment characteristics as well as local pressure coefficients serve to establish a data pool for code validation.     

Synergies of Earth science and space exploration

A more flexible policy basis from which to manage our planet in the 21st century is desirable. As one contribution, we note that synergies between space exploration and the preservation of our habitat exist, and that protecting life on Earth requires similar concepts and information as investigations of life beyond the Earth, including the expansion of human presence in space. Instrumentation and data handling to observe both planetary objects and planet Earth are based on similar techniques. Moreover, while planetary surface operations are conducted under different conditions, the technology to probe the surface and subsurface of both the Earth and other planets requires similar tools, such as radar, seismometers, and drilling devices. The Earth observation community has developed some exemplary tools and has featured successful international cooperation in data handling and sharing that could be equally well applied to robotic planetary exploration. Here we propose a network involving both communities that will enable the interchange of scientific insights and the development of new policies and management strategies. Those tools can provide a vital forum through which the management of this planet can be assisted, and in which a new bridge between the Earth-centric and space-centric communities can be built.