Evaluating Small Satellites: Is the Risk Worth It?

Faster, Better, Cheaper - pick any two say critics of NASA\u27s current approach to scientific satellites. As proof, they point to the recent failed or impaired small science satellites: Lewis (failed shortly after reaching orbit), Clark (cancelled before leaving the ground), NEAR (trajectory altered due to engine shutdown) and WIRE (failure resulting in depletion of cryogen). Although the space industry has greatly increased their utilization of small satellites to conduct space activities, the question remains, Is Faster, Better, Cheaper (FBC) yielding a good return on investment? This paper takes a historical look at traditional science missions either flown or started before the FBC era and compares them with missions designed under this new paradigm using a variety of metrics such as development time, cost per mission, and a newly proposed cost-effectiveness metric. Risk is discussd in terms of the failure rates (both catastrophic and partial) of both mission sets as well. Conclusions are reached on the relative merit ofFBC and whether FBC is just a slogan or actually a new, valid approach for spacecraft design

Helicobacter bilis Infection Alters Mucosal Bacteria and Modulates Colitis Development in Defined Microbiota Mice

Background: Helicobacter bilis infection of C3H/HeN mice harboring the altered Schaedler flora (ASF) triggers progressive immune responsiveness and the development of colitis. We sought to investigate temporal alterations in community structure of a defined (ASF-colonized) microbiota in normal and inflamed murine intestines and to correlate microbiota changes to histopathologic lesions. Methods: The colonic mucosal microbiota of healthy mice and ASF mice colonized with H. bilis for 3, 6, or 12 weeks were investigated by fluorescence in situ hybridization targeting the 16S ribosomal RNA genes of total bacteria, group-specific organisms, and individual ASF bacterial species. Microbial profiling of ASF and H. bilis abundance was performed on cecal contents. Results: Helicobacter bilis–colonized mice developed colitis associated with temporal changes in composition and spatial distribution of the mucosal microbiota. The number of total bacteria, ASF519, and helicobacter-positive bacteria were increased (P , 0.05), whereas ASF360/361-positive bacteria were decreased (P , 0.05) versus controls. Adherent biofilms in colitic mice were most often (P , 0.05) composed of total bacteria, ASF457, and H. bilis. Total numbers of ASF519 and H. bilis bacteria were positively correlated (P ¼ 0.03, r ¼ 0.39 and P , 0.0001, r ¼ 0.73), and total numbers of ASF360/361 bacteria were negatively correlated (P ¼ 0.003, r ¼ 20.53) to histopathologic score. Differences in cecal abundance of ASF members were not observed. Conclusions: Altered community structure with murine colitis is characterized by distinct ASF bacteria that interact with the colonic mucosa, by formation of an isolating interlaced layer, by attachment, or by invasion, and this interaction is differentially expressed over time

Randomized, controlled trial evaluating the effect of multi-strain probiotic on the mucosal microbiota in canine idiopathic inflammatory bowel disease

The intestinal microbiota is increasingly linked to the pathogenesis of idiopathic inflammatory bowel disease (IBD) in dogs. While studies have reported alterations in fecal (luminal) microbial populations, only limited information is available about the mucosal microbiota of IBD dogs at diagnosis and following medical therapy. Our aim was to characterize the mucosal microbiota and determine the clinical, microbiological, and mucosal homeostatic effects of probiotic treatment in dogs with IBD. Thirty four IBD dogs were randomized to receive standard therapy (ST = diet + prednisone) with or without probiotic. Tissue sections from endoscopic biopsies were evaluated by fluorescence in situ hybridization (FISH) on a quantifiable basis. Disease activity and changes in mucosal microbiota and tight junction protein (TJP) expression were assessed before and after 8 weeks of IBD therapy. ST and ST/probiotic therapy modulated the number of mucosal bacteria of IBD dogs in a similar fashion. Both treatments increased the numbers of total bacteria and individual species residing within adherent mucus, with ST therapy increasing Bifidobacterium spp. and ST/probiotic therapy increasing Lactobacillus spp (P \u3c 0.05 for both), respectively. Both treatments were associated with rapid clinical remission but not improvement in histopathologic inflammation. Probiotic therapy was associated with upregulated (P \u3c 0.05) expression of TJPs E-cadherin, occludin, and zonulin versus ST. The probiotic effect on mucosal bacteria is similar to that of IBD dogs receiving ST. IBD dogs fed probiotic had increased TJP expression suggesting that probiotic may have beneficial effects on mucosal homeostasis

Seafloor character and sedimentary processes in eastern Long Island Sound and western Block Island Sound

Author Posting. © The Author(s), 2006. This is the author's version of the work. It is posted here by permission of Springer for personal use, not for redistribution. The definitive version was published in Geo-Marine Letters 26 (2006): 59-68, doi: 10.1007/s00367-006-0016-4.Multibeam bathymetric data and seismic-reflection profiles collected in eastern Long Island and western Block Island Sounds reveal previously unrecognized glacial features and modern bedforms. Glacial features include an ice-sculptured bedrock surface, a newly identified recessional moraine, exposed glaciolacustrine sediments, and remnants of stagnant-ice-contact deposits. Modern bedforms include fields of transverse sand waves, barchanoid waves, giant scour depressions, and pockmarks. Bedform asymmetry and scour around obstructions indicate that net sediment transport is westward across the northern par of the study area near Fishers Island and eastward across the southern par near Great Gull Island.This work was supported by the Coastal and Marine Geology Program of the U.S. Geological Survey, the Connecticut Department of Environmental Protection, and the Atlantic Hydrographic Branch of the National Oceanic and Atmospheric Administration

The CI-FLOW Project: A System for Total Water Level Prediction from the Summit to the Sea

Kildow et al. (2009) reported that coastal states support 81% of the U.S. population and generate 83 percent [$11.4 trillion (U.S. dollars) in 2007] of U.S. gross domestic product. Population trends show that a majority of coastal communities have transitioned from a seasonal, predominantly weekend, tourist-based economy to a year-round, permanently based, business economy where industry expands along shorelines and the workforce commutes from inland locations. As a result of this transition, costs associated with damage to the civil infrastructure and disruptions to local and regional economies due to coastal flooding events are escalating, pushing requirements for a new generation of flood prediction technologies and hydrologic decision support tools

Benchmarking the Small Satellite Industry – Identifying Emerging Trends to Increase Access to Space

Small satellites have the potential to allow rapid and affordable access to space; especially for small satellites or payloads that are used to test or validate new concepts or technologies. But limited launch manifest opportunities can hinder the exploitation of the qualities that make small satellites attractive. This paper outlines the work done to collect information on historical and developmental small satellite missions. Trends from the data and the implication on future small satellite missions are described. These trends and common characteristics are then tied to the limited manifesting opportunities offered to small satellites. Finally, development of future launch capability and how that could impact the small satellite market is addressed. Possessing knowledge gained from a thorough benchmarking effort of the small satellite industry can help improve the ability of gaining manifesting opportunities, thereby increasing access to space

Benchmarking the Small Satellite Industry – Identifying Emerging Trends to Increase Access to Space

Small satellites have the potential to allow rapid and affordable access to space; especially for small satellites or payloads that are used to test or validate new concepts or technologies. But limited launch manifest opportunities can hinder the exploitation of the qualities that make small satellites attractive. This paper outlines the work done to collect information on historical and developmental small satellite missions. Trends from the data and the implication on future small satellite missions are described. These trends and common characteristics are then tied to the limited manifesting opportunities offered to small satellites. Finally, development of future launch capability and how that could impact the small satellite market is addressed. Possessing knowledge gained from a thorough benchmarking effort of the small satellite industry can help improve the ability of gaining manifesting opportunities, thereby increasing access to space

Advanced Wireless Communications Technologies for Low Power, Reconfigurable Small Satellite Radios

Advances in smart antennas, coding theory, power amplifiers, low-power electronics, and softwaredefined radios have dramatically impacted terrestrial communications. The improvements achieved in frequency reuse, interference mitigation, handset battery life, error performance, and hardware reconfigurability can be transitioned to small satellite communications systems. The stringent power budgets, limited antenna apertures, and rapid development times associated with small satellites make these technologies particularly important. Also, the shorter lifetimes and higher levels of acceptable risk typical of small satellite missions make the utilization of advanced commercial-off-the-shelf (COTS) components feasible. This paper describes an effort underway to study flexible radio architectures that can rapidly leverage emerging wireless technologies for small satellite communications. Employing a software-defined radio architecture and a modular hardware design results in a radio that can be rapidly reconfigured to meet a wide range of mission requirements. Smart antennas, high-efficiency power amplifiers, and advanced error-correction coding all facilitate significant reductions in the power dissipated per bit transmitted in downlinks and crosslinks. Advances in lowpower, high-rate signal conversion and signal processing circuits are also being exploited to boost capabilities while minimizing the associated dissipated power

The Rise and Fall of the Capital Asset – An Investigation into the Aerospace Industry Dynamics and Emerging Small Satellite Missions

Many studies have been conducted over the years on the relationship between spacecraft design, mission utility, cost/complexity, and the Aerospace community’s ability to “commoditize” spacecraft designs and/or missions. During the Fifties and Sixties, spacecraft were limited by launch vehicle throw-weight and technical performance limitations, particularly computer processing speeds. During the Seventies and into the Eighties the personal computer revolution enabled more and more processing capability to be utilized in spacecraft bus and mission designs. This resulted in industry developed, large, “Capital” assets that took years to design, develop, integrate, test, and eventually operate. These systems, due to the very nature of their multi-mission capabilities, became critical to our nation. These systems had to function, and function reliably, therefore requiring extensive support infrastructures to assure mission success. As the Cold War ended, commercial space began to prosper. In recent years, the advanced technologies that enabled increased Capital Asset performance have also enabled small satellites to reach performance levels that could be used for operational missions. This, coupled with new mission types that are now feasible, have lead to a renewed and significant interest in small satellites. This paper investigates the changing dynamics of the market and technologies that have placed small satellites and Capital Assets at a crossroads

The IRIS Project: A New Architecture or a Small Satellite Imaging Mission

Utah State University students have developed an earth-imaging satellite mission designed for specifically for the promising, low-cost RASCAL launch platform. Designed over a semester-long space system design class, the mission is intended to capture high quality images of earth from a low-Earth orbit. The total mission cost is estimated at $10 million including satellite design, fabrication, launch, and mission operations. Students used the university’s new Space System Analysis Laboratory, a concurrent design center, to assess design trades and develop the system architecture. The mission architecture, mission elements and satellite design are presented