Tuesday, June 8, 2010

June 3 - Dreaming big: planning a human mission to outer solar system‏

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Click the link if you don't receive the images/can't access the links. The last link is a more in depth paper concerning the subject.

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Dreaming big: planning a human mission to outer solar system

By Kunio M. Sayanagi | Last updated June 1, 2010 9:16 AM
Scientists are usually a realistic bunch—our salaries depend on proposing projects that are doable with the tools we have in our hands, and our plans usually involve prudent small steps rather than aiming for risky big leaps. But we sometimes dream too, and when we dream, we dream big, even if we dream very seriously. In a project that was part dream and part technical design exercise, a group of scientists drew up a plan to send humans to the outer fringes of our solar system in the later half of the 21st century. The result was a spaceship that may look similar to Discovery 1 from the movie 2001: A Space Odyssey.

The new exercise was carried out at Johns Hopkins University’s Applied Physics Laboratory, the starting point for many unmanned space missions—the study’s lead author, Ralph McNutt, has been a prominent figure in robotic planetary exploration for many years. The plans, published last month in the Johns Hopkins APL Technical Digest, would take us to Jupiter, Saturn, Uranus, Neptune, and Pluto starting around year 2050.

The mission design involves future advanced technologies such as an onboard 100MW nuclear reactor powering magnetoplasmadynamic thrusters, which are basically electric ion propulsion engines on hyper-steroids. Electric propulsion systems, which use electricity generated by solar panels to accelerate ionized molecules to produce thrust, have been successfully used on missions such as Deep Space 1, Dawn and Hayabusa. The proposed dream missions would use the electricity generated by a nuclear reactor to shoot a stream of plasma to power us to the distant planets.

The need for an extreme propulsion system arises because the astronauts would be exposed to high doses of galactic cosmic radiation, so the mission durations must be kept relatively short. Even on the International Space Station, which orbits within the protection of Earth’s magnetic field, astronauts are exposed to radiation at twice the limit for US airline pilots.
In a deep-space environment, the problem is even worse—to keep the radiation exposure to a level comparable to Earth’s surface aboard these spacecraft, the scientists calculate that an aluminum shield weighing about 4240 metric tons would be required for a 10-crew spaceboat, which would make the mission a complete no-go even with future technologies. So, the scientists opted to reduce radiation exposure by shortening the missions, which meant beefing up the propulsion system.
Approximate scale comparisons of various existing and conceptual launch vehicles
Image credit: Johns Hopkins University

Their travel plan to Neptune, for example, was designed with a 5-year total mission duration to limit the radiation exposure. That would take us to Neptune in less than two years, which means going significantly faster than anything we have ever launched. For example, the New Horizons probe currently en route to Pluto—the fastest man-made object in space—has reached the distance of 16.74 AUs from the sun as of this writing. That took about 4.5 years, and it's only a little more than halfway to Neptune’s orbit at 30 AU.

To design the mission, the scientists also gave considerations to the size of the living space in which the astronauts would spend 5 years of their lives. They have compared the sizes of past large space habitats such as the Skylab, the Russian Mir, and the International Space Station to determine that approximately 200 cubic meters per person of habitable volume makes for a healthy living space. If the habitable space is spherical, a crew of 10 would need a 7.8 meter radius, or about twice the size of Discovery 1 in 2001: A Space Odyssey.

Not surprisingly, this dream voyage is not cheap. Based on the costs of historic large technological endeavors, the scientists project that a mission to Neptune would cost roughly 4 trillion dollars. To put this number in perspective, in 2009, the GDP of the US was about 14 trillion dollars, and the US federal budget was about 3.1 trillion dollars, of which NASA received only $17.6 billion. Due to the extreme financial cost associated with the plan, the authors conclude that, for the mission to materialize at all, it would have to be a large-scale international collaborative effort.

It is worth noting that the study is a technical dream exercise to show how it could be done. But it is exciting to think that such an exploration plan is no longer a pure fantasy, and it can now be considered in enough detail that we can identify what specific technologies must still be developed.
The value of such a mission is intrinsically subjective, and the economic value for such an effort is difficult to gauge at this stage. However, human beings have always dreamed of flying ever since we recognized the empty blue sky above us, and that imagination did not stop when we recognized the vast outer space beyond; the drive for exploration is human nature. The instinctive yearning to know what lies beyond the horizon has been one of the driving forces underlying human progress. So why stop here now?

Ralph L. McNutt et al. (2010) “Human Missions Throughout the Outer Solar System: Requirements and Implementations

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How to Digitally Record/Video a UFO sighting:

Como registar digitalmente ou gravar um vídeo de um avistamento de um UFO:

Stabilize the camera on a tripod. If there is no tripod, then set it on top of a stable, flat surface. If that is not possible lean against a wall to stabilize your body and prevent the camera from filming in a shaky, unsteady manner.

Estabilize a camera com um tripé. Se não tiver um tripé, então coloque-a em cima de uma superfície estável. Se não for possível, então encoste-se a uma parede para estabilizar o corpo e evitar que a camera registe de maneira tremida e instável.

Provide visual reference points for comparison. This includes the horizon, treetops, lampposts, houses, and geographical landmarks (i.e., Horsetooth Reservoir, Mt. Adams, etc.) Provide this in the video whenever is appropriate and doesn’t detract from what your focus is, the UFO.

Forneça pontos visuais de referência para comparação. Isso inclui o horizonte, cimo das árvores, postes de iluminação, pontos de referência geográficos (como o Reservatório de Horsetooth, Mone Adams, etc) Forneça esses pontos no vídeo sempre que for apropriado e não se distraia do que é o seu foco, o UFO/a Nave.

Narrate your videotape. Provide details of the date, time, location, and direction (N,S,E,W) you are looking in. Provide your observations on the weather, including approximate temperature, windspeed, any visible cloud cover or noticeable weather anomalies or events. Narrate on the shape, size, color, movements, approximate altitude of the UFO, etc and what it appears to be doing. Also include any unusual physical, psychological or emotional sensations you might have. Narrate any visual reference points on camera so they correlate with what the viewer will see, and thereby will be better able to understand.

Faça a narração do vídeo. Forneça pormenores sobre a data, hora, local e direcção (Norte, Sul, Este, Oeste) que está a observar. Faça observações sobre as condições atmosféricas, incluindo a temperatura aproximada, velocidade do vento, quantidade de nuvens, anomalias ou acontecimentos meteorológicos evidentes. Descreva a forma, o tamanho, a cor, os movimentos, a altitude aproximada onde se encontra o UFO/nave, etc e o que aparenta estar a fazer. Inclua também quaisquer aspectos pouco habituais de sensações físicas, psicológicas ou emocionais que possa ter. Faça a narração de todos os pontos de referência visual que o espectador irá ver e que, deste modo, será capaz de compreender melhor.

Be persistent and consistent. Return to the scene to videotape and record at this same location. If you have been successful once, the UFO sightings may be occurring in this region regularly, perhaps for specific reasons unknown, and you may be successful again. You may also wish to return to the same location at a different time of day (daylight hours) for better orientation and reference. Film just a minute or two under “normal” circumstances for comparison. Write down what you remember immediately after. As soon as you are done recording the experience/event, immediately write down your impressions, memories, thoughts, emotions, etc. so it is on the record in writing. If there were other witnesses, have them independently record their own impressions, thoughts, etc. Include in this exercise any drawings, sketches, or diagrams. Make sure you date and sign your documentation.

Seja persistente e não contraditório. Volte ao local da cena e registe o mesmo local. Se foi bem sucedido uma vez, pode ser que nessa região ocorram avistamentos de UFOs/naves com regularidade, talvez por razões específicas desconhecidas, e talvez possa ser novamente bem sucedido. Pode também desejar voltar ao mesmo lugar a horas diferentes do dia (durante as horas de luz)para ter uma orientação e referência melhor. Filme apenas um ,inuto ou dois em circunstâncias “normais” para ter um termo de comparação. Escreva tudo o que viu imediatamente após o acontecimento. Logo após ter feito o registo da experiência/acontecimento, escreva imediatamente as impressões, memórias, pensamentos, emoções, etc para que fiquem registadas por escrito. Se houver outras testemunhas, peça-lhes para registar independentemente as suas próprias impressões, pensamentos, etc. Inclua quaisquer desenhos, esbolos, diagramas. Certifique-se que data e assina o seu documento/testemunho.

Always be prepared. Have a digital camera or better yet a video camera with you, charged and ready to go, at all times. Make sure you know how to use your camera (and your cell phone video/photo camera) quickly and properly. These events can occur suddenly, unexpectedly, and often quite randomly, so you will need to be prepared.

Esteja sempre preparado, Tenha sempre uma camera digital, melhor ainda, uma camera vídeo consigo, carregada e pronta a usar sempre que necessário. Certifique-se que sabe como lidar com a sua camera (ou com o seu celular/camera fotográfica) rápida e adequadamente. Esses acontecimentos podem acontecer súbita e inesperadamente e, por vezes, acidentalmente, por isso, necessita estar preparado.

Look up. Be prepared. Report. Share.

Olhe para cima, Esteja preparado, Relate, Partilhe.



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