Tether Satellite System Collision Study

A study was performed to determine the probability of collision with resident space objects and untrackable debris for the tether component of the Tethered Satellite System (TSS) after it broke away from the Space Shuttle orbiter (mission STS-75) in February 1996. Both an analytical and a numerical approach were used in this study, and the results obtained with these two methods were found to be in good agreement. These results show that the deployed tether is expected to have been impacted by several particles 0.1mm or larger in size. The probability of collision with objects 10cm in size or larger was on the order of 10^–3 per month. Since the severed tether reentered within one month after deployment, the collision hazard to other objects while in orbit was small. The analytical methods used in this study are useful for tether collision evaluations in general.     

The Brazilian scientific microsatellite SACI-1

The National Space Research Institute (INPE) is developing the first Brazilian Scientific Microsatellite (SACI-1) based on the vanguard technology and on the experience acquired through projects developed by Brazilian Space Program. The SACI-1 is a 750km polar orbit satellite. The spacecraft will combine spin stabilization with geomagnetic control and has a total mass of 60 kg. The overall dimensions are 640×470×470 mm. The SACI-1 satellite shall be launched together with CBERS (China-Brazil Earth Resource Satellite). Its platform is being designed for multiple mission applications. The Brazilian Academy of Sciences has selected four scientific payloads that characterize the mission. The scientific experiments are: ORCAS (Solar and Anomalous Cosmic Rays Observation in the Magnetosphere), PLASMEX (Study of Plasma Bubbles), FOTSAT (Airglow Photometer), and MAGNEX (Geomagnetic Experiment).     

Positive consequences of SETI before detection

Even before a signal is detected, six positive consequences will result from the scientific search for extraterrestrial intelligence, usually called SETI. (1) Humanity’s self-image: SETI has enlarged our view of ourselves and enhanced our sense of meaning. Increasingly, we feel a kinship with the civilizations whose signals we are trying to detect. (2) A fresh perspective: SETI forces us to think about how extraterrestrials might perceive us. This gives us a fresh perspective on our society’s values, priorities, laws and foibles. (3) Questions: SETI is stimulating thought and discussion about several fundamental questions. (4) Education: some broad-gage educational programs have already been centered around SETI. (5) Tangible spin-offs: in addition to providing jobs for some people, SETI provides various spin-offs, such as search methods, computer software, data, and international scientific cooperation. (6) Future scenarios: SETI will increasingly stimulate us to think carefully about possible detection scenarios and their consequences, about our reply, and generally about the role of extraterrestrial communication in our long-term future. Such thinking leads, in turn, to fresh perspectives on the SETI enterprise itself.     

Operational continuity of the global meteorological satellite network

The global network of meteorological satellites used different forms of international cooperation during its development, and some of these forms continue. Concern about continued operation of the global network led the WMO to study the issues and to adopt a long-term policy and strategy based on a shared meteorological satellite network. Nations need to consider how to combine their meteorological and space-related organizations in a partnership role, so they can directly contribute to a future global network of meteorological satellites. Some examples are cited to demonstrate that increased direct participation is a valid and feasible objective.     

Space Station habitability research.

The purpose and scope of the Habitability Research Group within the Space Human Factors Office at the NASA/Ames Research Center is described. Both near-term and long-term research objectives in the space human factors program pertaining to the U.S. manned Space Station are introduced. The concept of habitability and its relevancy to the U.S. space program is defined within a historical context. The relationship of habitability research to the optimization of environmental and operational determinants of productivity is discussed. Ongoing habitability research efforts pertaining to living and working on the Space Station are described.     

Mars Direct: Humans to the red planet by 1999

“Mars Direct”, is an approach to the space Exploration Initiative that allows for the rapid initiation of manned Mars exploration, possibly as early as 1999. The approach does not require any on-orbit assembly or refueling or any support from the Space Station or other orbital infrastructure. Furthermore, the Mars Direct plan is not merely a “flags and footprints” one-shot expedition, but puts into place immediately an economical method of Earth-Mars transportation, real surface exploratory mobility, and significant base capabilities that can evolve into a mostly self-sufficient Mars settlement. This paper presents both the initial and evolutionary phases of the Mars Direct plan. In the initial phase, only chemical propulsion is used, sendig 4 persons on conjunction class Mars exploratory missions. Two heavy lift booster launches are required to support each mission. The first launch delivers an unfueled Earth Return Vehicle (ERV) to the martian surface, where it fills itself with methane/oxygen bipropellant manufactured primarily out of indigenous resources. After propellant production is completed, a second launch delivers the crew to the prepared site, where they conduct regional exploration for 1.5 years and then return directly to Earth in the ERV. In the second phase of Mars Direct, nuclear thermal propulsion is used to cut crew transit times in half, increase cargo delivery capacity, and to create the potential for true global mobility through the use of CO₂ propelled ballistic hopping vehicles (“NIMFs”). In this paper we present both phases of the Mars Direct plan, including mission architecture, vehicle designs, and exploratory strategy leading to the establishment of a 48 person permanent Mars base. Some speculative thoughts on the possibility of actually colonizing Mars are also presented.     

The past and future of the earth-moon system

The lunar orbit is presently expanding due, we believe, to tidal friction, i.e. the attraction of the moon for the tides it raises on the rotating Earth. The Moon may therefore have been significantly closer to the Earth in the distant past, a point of great interest to those studying the lunar origin. This work presents the results of the integration of the equations which govern the rates of change of the lunar orbit elements and the angular momentum of the Earth. Results are presented for both the past and future of the Earth-Moon system.     

Anesthesia, surgical aid and resuscitation in manned space missions.

When discussing problems related to medical service in space flight, particular attention should be given to the specific living conditions and changes associated with space flight. In disease and injury, surgery can be provided only after conservative therapy has failed. In this context gnotobiological chambers allowing surgery in aseptic conditions seem promising. A portable set of interchangeable surgical tools should be made of light-weight alloys that can be readily sterilized. Electroanalgesia in combination with auriculoacupuncture as well as peridureal anesthesia may be used as they allow normal operations in autonomous space flight conditions. Changes in the sympatho-adrenal and kallikrein-kinin systems, as well as water-electrolyte balance, should be taken into account in developing methods and means of medical service in critical situations. Special attention should be given to the prevention and treatment of brain edema in view of weightlessness-induced cephalad fluid shifts.     

Engineering concepts for inflatable Mars surface greenhouses.

A major challenge of designing a bioregenerative life support system for Mars is the reduction of the mass, volume, power, thermal and crew-time requirements. Structural mass of the greenhouse could be saved by operating the greenhouse at low atmospheric pressure. This paper investigates the feasibility of this concept. The method of equivalent system mass is used to compare greenhouses operated at high atmospheric pressure to greenhouses operated at low pressure for three different lighting methods: natural, artificial and hybrid lighting.