Pilots for space tourism

This article sheds light on the key player needed for any space tourism adventure: the pilot who flies the spacecraft. The paper addresses the potential benefits of including a pilot at the controls when designing a space tourism spacecraft. It examines the basic qualifications and advanced skills required of space tourism pilots and discusses key training requirements for selected pilots and space pilots' pay and benefits. In addition, the research concludes that, just as the pioneers of passenger transport in aviation entertained and captured the interest of their passengers, the space pilot should have the skills of a tour guide.     

轨道测量差分精确定轨方法

航天器轨道精确测定重要环节之一是有效地消除观测系统误差,在轨道测量数据处理时,一类是利用轨道约束自校准技术来估算和校准系统误差,另一类可以应用测元差分方法来消除系统误差(例如导航卫星测定目标)。本文提出一种新的差分技术,即利用观测数据时序差分消除系统误差技术,并推导相应确定航天器轨道的公式。     

Remote sensing satellites, superpower relations and public diplomacy

This article examines the consequences for US-Soviet relations of the wide availability of commercial remote sensing images. Both SPOT and Landsat images have recently been used, by the Western media as well as the superpowers themselves, to comment publicly on arms control controversies and environmental disasters, notably Chernobyl. Looking to the future, several scenarios involving third-party intervention in treaty compliance disputes, supported by commercial imagery, are discussed: unpleasant consequences could conceivably follow, but experience to date indicates that outcomes are most likely to foster openness and stability between the superpowers.     

The stable transition to strategic defences An example of the empty set

The Bush administration is committed to achieving the rapid development and early deployment of some kind of space-based missile defence, with Brilliant Pebbles the favoured candidate. This article examines the conditions necessary to maintain stability during the extended period of transition from offence to defence dominance, and concludes that an agreement incorporating these conditions is most unlikely to be achieved. If the superpowers could agree to such a transition, with its prerequisite of virtually total strategic disarmament, they would agree to nuclear disarmament itself.     

Common freshwater cyanobacteria grow in 100% CO2

Cyanobacteria and similar organisms produced most of the oxygen found in Earth's atmosphere, which implies that early photosynthetic organisms would have lived in an atmosphere that was rich in CO2 and poor in O2. We investigated the tolerance of several cyanobacteria to very high (>20 kPa) concentrations of atmospheric CO2. Cultures of Synechococcus PCC7942, Synechocystis PCC7942, Plectonema boryanum, and Anabaena sp. were grown in liquid culture sparged with CO2-enriched air. All four strains grew when transferred from ambient CO2 to 20 kPa partial pressure of CO2 (pCO2), but none of them tolerated direct transfer to 40 kPa pCO2. Synechococcus and Anabaena survived 101 kPa (100%) pCO2 when pressure was gradually increased by 15 kPa per day, and Plectonema actively grew under these conditions. All four strains grew in an anoxic atmosphere of 5 kPa pCO2 in N2. Strains that were sensitive to high CO2 were also sensitive to low initial pH (pH 5-6). However, low pH in itself was not sufficient to prevent growth. Although mechanisms of damage and survival are still under investigation, we have shown that modern cyanobacteria can survive under Earth's primordial conditions and that cyanobacteria-like organisms could have flourished under conditions on early Mars, which probably had an atmosphere similar to early Earth's.     

ATLAS2K--以信号描述为核心的可扩展的可移植的自动测试语言

详细介绍了以信号描述为核心的新一代测试语言ATLAS2K的特点及层模型，并提出了ATLAS2K在自动测试设备ATE中的应用。     

直升机主最低设备清单的确定

为提高民用直升机的利用率和经济性,可编制主最低设备清单(MMEL).根据AC313型机MMEL项目的经验,总结出民用直升机MMEL的确定逻辑决断程序,并探讨MMEL在军用直升机上的应用前景.     

Effects of space flight and IGF-1 on immune function

We tested the hypothesis that insulin-like growth factor-1 (IGF-1) would ameliorate space flight-induced effects on the immune system. Twelve male, Sprague-Dawley rats, surgically implanted with mini osmotic pumps, were subjected to space flight for 10 days on STS-77. Six rats received 10 mg/kg/day of IGF-1 and 6 rats received saline. Flight animals had a lymphocytopenia and granulocytosis which were reversed by IGF-1. Flight animals had significantly higher corticosterone levels than ground controls but IGF-1 did not impact this stress hormone. Therefore, the reversed granulocytosis did not correlate with serum corticosterone. Space flight and IGF-1 also combined to induce a monocytopenia that was not evident in ground control animals treated with IGF-1 or in animals subjected to space flight but given physiological saline. There was a significant increase in spleen weights in vivarium animals treated with IGF-1, however, this change did not occur in flight animals. We observed reduced agonist-induced lymph node cell proliferation by cells from flight animals compared to ground controls. The reduced proliferation was not augmented by IGF-1 treatment. There was enhanced secretion of TNF, IL-6 and NO by flight-animal peritoneal macrophages compared to vivarium controls, however, O₂ secretion was not affected. These data suggest that IGF-1 can ameliorate some of the effects of space flight but that space flight can also impact the normal response to IGF-1.     

Self-discharge losses in lithium-ion cells

The self-discharge losses in several lithium-ion cell designs have been measured by three different methods. The losses are separated into time-dependent and state-of-charge dependent contributions. For most cycling conditions, the time-dependent self-discharge losses are dominant; however, after several months of stand on open circuit or float charge, the state-of-charge dependent losses become significant. The self-discharge rate has been found to not increase monotonically with state-of-charge, but to drop somewhat at intermediate states of charge. The implications of these measurements for maintaining balanced cell capacities in batteries and establishing optimum storage voltage levels for batteries are discussed.