CHUTE D'UN CARGO SPATIAL RUSSE

By: Scribe Valdemir
SOURCE:
http://tempsreel.nouvelobs.com/sciences/20150429.OBS8192/chute-d-un-cargo-spatial-russe-quatre-questions-pour-tout-comprendre.html

Chute d'un cargo spatial russe : quatre questions pour tout comprendre

Par L'Obs avec AFP

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Publié le 29-04-2015 à 16h59

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Le vaisseau Progress est en chute libre et incontrôlée vers la Terre après une perte de signal. Le point pour tout comprendre.

Le cargo spatial russe Progress vu depuis la station spatiale internationale (ISS) (Capture d'écran Nasa)

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• Perte de contrôle d'un cargo spatial russe qui chute vers la Terre

Les opérateurs de vol russes ont perdu le contrôle du vaisseau cargo inhabité Progress qui devait ravitailler la Station spatiale internationale (ISS) et qui retombera sur Terre, a déclaré mercredi 29 avril un responsable au sein du complexe spatial russe. "Il a commencé sa chute", a affirmé ce responsable sous couvert d'anonymat, ajoutant que "des réactions totalement incontrôlables avaient commencé". Le point sur ce que l'on sait.

Que s'est-il passé ?

Les opérateurs russes avaient rencontré des problèmes de transmission de données peu après son lancement mardi, par une fusée Soyouz, du cosmodrome de Baïkonour et avaient décidé de changer le plan de vol du vaisseau.

Les autorités avaient pourtant assuré mardi que le Progress remplirait bien sa mission et s'amarrerait le 30 avril à l'ISS, contre un vol initialement prévu de six heures. Ce n'est désormais plus à l'ordre du jour et le cargo spatial devrait retomber sur la Terre "dans des conditions incontrôlables".

Peut-on éviter la chute ?

Selon le responsable russe, les contrôleurs de vol russes vont essayer encore deux fois de rétablir la liaison avec le vaisseau, mais sans grand espoir d'y parvenir. "Il est impossible de dire quand exactement le cargo retombera sur Terre, cela dépend de beaucoup de facteurs. Mais la chute s'effectuera dans des conditions incontrôlables", selon la même source.

Où et quand aura lieu la chute sur Terre ?

Il est impossible de dire quand exactement le cargo retombera sur Terre, cela dépend de beaucoup de facteurs. Mais la chute s'effectuera dans des conditions incontrôlables", selon la même source.

Thomas Reiter, le directeur des vols et des opérations de l'Agence spatiale européenne, explique au "Guardian" que si les Russes ne reprennent pas le contrôle de l'engin spatial, le cargo pourrait toucher la terre d'ici une semaine et demi au maximum.

Le cargo spatial russe étant en perdition, des bouts de l'engin pourraient toucher la terre ferme. Toutefois le risque pour la population est mince, rappelle le "Guardian". Les deux tiers de la surface de la Terre sont couverts par de l'eau. Et seulement 3% des continents sont occupés par des zones urbaines.

Normalement, les cargos spatiaux sont contrôlés lors de leur descente et entrent par un chemin menant au-dessus de l'océan Pacifique. Le but est que les fragments des cargos, qui n'ont pas été détruits lors de l'entrée dans l'atmosphère, tombent dans l'océan.

Que transportait le cargo spatial ?

Le Progress M-27M transportait du matériel scientifique et des produits de première nécessité, comme de l'eau ou de la nourriture, mais sa perte ne créera pas de problème pour les six membres d'équipage de l'ISS, qui disposent de plusieurs mois de réserves.

La Nasa a de son côté confirmé que le vaisseau "ne transporte aucun ravitaillement essentiel pour le fonctionnement de la partie américaine de l'ISS".

Les segments russe et américain de la Station continuent à fonctionner normalement et ont suffisamment de réserves pour aller bien au-delà de l'arrivée du prochain vaisseau de ravitaillement en juin", a ajouté l'Agence mardi.

Il s'agit du vaisseau automatique Dragon de la société américaine SpaceX, dont le lancement de Cap Canaveral en Floride est prévu au plus tôt le 19 juin. Il devra livrer environ 2,2 tonnes de matériel scientifique et de provisions (aliments, eau...).

MAN WAS IT THE MOON?

Man was it the moon?

Over the last several decades the Moon landings of the late 60s and early 70s have garnered much scrutiny. Some have argued that it would have been physically and technologically impossible to land men on the Moon and return them home. Was it all a hoax? Did NASA fake the Moon missions on a sound stage? I'll discuss the claims of the conspiracy theorists and let you determine for your self if man really landed on the Moon. Did you think of an issue I didn't address? Send me an email and I will be sure to add it.

1. Why Are Their No Stars In Photos Taken On The Moon?

Image Credit: NASA

In most of the photos taken during the lunar landing missions there stars are absent in the background. Why is that? Clearly, in the pictures there is a considerable amount of light from the Sun. Also, the Sun light is reflecting off the lunar surface (more on that later). So, in order to take crisp pictures, the camera needed to be set to take pictures in high light. Using a very high frame rate, and small aperture setting, the camera can not gather enough light from the very dim stars to be seen.

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2. Why Can We See Objects In Shadow?

Image Credit: NASA

There are many instances of this in Moon landing images. Objects in the shadow of another object, like this image of Buzz Aldrin in the shadow of the Lunar Lander, are clearly visible. How is it possible that we can see him so clearly? The problem is with our assumption that the Sun is the only source of light on the Moon. Now, obviously the Moon does not produce its own light, but it does reflect the Sun's light very well! This is also the reason that you can make out the details on the front of an astronaut's space suit (see image in item 3) in photos where the Sun is behind him. Light is being reflected from the Lunar surface to illuminate it.

3. Who Took This Picture Of Buzz Aldrin?

Image Credit: NASA

There are actually two questions that are commonly asked about this photo, the first was addressed in item 2 above. The second question, is who took this image? It is difficult to see with this small image, but in the reflection of Buzz's visor it is possible to make out Neil Armstrong standing in front of him. But he does not appear to be holding a camera. That is because the cameras were mounted on the chest area of their suits. Armstrong was holding his arm up to his chest to take the picture, which can been seen more easily in larger images.

4. Why Is The American Flag Waving?

Image Credit: NASA

Well the answer is that its not waving! In images of the American flag on the Moon, the flag appears rippled, as if it is being blown in the wind. But this is actually due to the design of the flag. It was created to have rigid, extendable support pieces on the top and bottom so that the flag would look taut. However, when the astronauts were setting the flag up, the bottom rod was jammed, and would not fully extend. Then, as they were twisting the pole into the ground, the motion caused the ripples we see. On a later mission, astronauts were going to repair the defective rod, but decided they liked the wavy look so left it the way it was.

5. Why Do The Shadows Point In Different Directions?

Image Credit: NASA

In some of the photos, shadows for different objects in the images point in different directions. If the Sun is causing the shadows, shouldn't they all point in the same direction? Well, yes and no. They would all point in the same direction if everything was on the same level. This, however was not the case. Because of the uniformly grey terrain of the Moon, it is sometimes difficult to distinguish changes in elevation. However, these changes can influence the apparent direction of shadows for objects in the frame. In this image the shadow of the lander points directly to the right, while the astronauts shadow points down and to the right. This is because the Moons surface is at a slight incline where he is standing.

6. How Did The Astronauts Make It Through The Van Allen Radiation Belts?

Image Credit: NASA

The Van Allen radiation belts are doughnut shaped regions of space in the Earth's magnetic field that trap very high energy protons and electrons. As a result, some wonder how astronauts could have passed through the belts without being killed by the radiation from these particles. NASA quotes that the radiation would be about 2500 rem per year with almost no shielding. Considering how quickly the astronauts passed through the belts, they only would have been exposed to about 0.05 rem during the trip there and back. However, I have seen some numbers quoted as high as 2 rem during the trip. But even assuming levels that high, the rate at which their bodies could have absorbed the radiation still would have been within safe levels.

7. Why Is There No Blast Crater Where the Module Landed?

Image Credit: NASA

During the descent, the lunar lander would have fired its rocket to slow it down. So, why is there no blast crater on the surface of the Moon? The lander had a very power rocket, capable of 10,000 pounds of thrust. But they didn't need to use all 10,000 pounds of thrust to land the module, in fact they needed only about 3,000 pounds. Concentrated all in one place it should have produced a noticeable crater. But there is no air on the Moon, therefore there is no pressure causing the exhaust gas to go straight down onto a concentrated area. It would have spread out over a wide area. If you calculate the pressure on the surface, it would have been only 1.5 pounds of pressure per square inch; not enough to cause a blast crater.

8. Why Is There No Visible Flame From The Rocket?

Image Credit: NASA

In all of the images and videos of the lunar module landing and taking off, there are no visible flames from the rocket. How is that? Simple, the type of fuel that was used (a mixture of hydrazine and dinitrogen tetroxide) mixes together and ignites instantly, producing a "flame" that is completely transparent. This fuel mixture is still used in some orbiting space craft, and images of those craft clearly show no flames.

HOMEM NA LUA NÃO É UMA FARSA

Circula pela internet algumas especulações sobre a legitimidade e veracidade sobre o homem ter ou não ido a lua. Realmente vivemos uma época que não dá para acreditar em ninguém, mas neste caso, após apurada investigação pude observar que não há dúvidas, o homem realmente esteve na lua. Peguei este video e publiquei, pois suas explanações servem para dirimir qualquer dúvida. (IPor Valdemir Mota de Menezes, o escriba)



Travels across the Internet some speculation about the legitimacy and veracity of the man to have or not gone to the moon. Actually live in an age that you can not trust anyone, but in this case, after accurate investigation I noticed that there is no doubt the man was actually on the moon. I took this video and published as his explanations serve to dispel any doubt. (By: Valdemir Mota de Menezes, the scribe)

NAVE STEREO

El Sol, completo en una imagen
07.02.2011 | Dos sondas gemelas de la NASA, las naves Stereo, acaban de llegar a posiciones opuestas en ambos lados del astro y envían imágenes

JAPAN ROCKET

ASTRONAUTIC

Added On January 22, 2011

Japan launches an unmanned rocket on a mission to deliver cargo to the International Space Station.

TELESCOPIO PLANCK

Revelan una imagen global del Universo
05.07.2010 | El telescopio Planck de la Agencia Espacial Europea presentó una nueva perspectiva de las estrellas y las galaxias e información adicional tras el Big Bang (elmundoTV)

SATELLITE GALILEO

Découverte des projets européens développés grâce à Galiléo et Egnos.
4-3-2010




Galileo est un projet européen de système de positionnement par satellites. En test depuis fin 2005 suite aux lancements des 2 satellites Giove-A et Giove-B en décembre 2005 et avril 2008, les 4 premiers satellites de la constellation seront testés à partir de 2011 et le système sera opérationnel en 2014[1].

Galileo sera « couramment utilisé dans les transports maritimes, aériens et terrestres, les opérations de secours et de sauvetage, les travaux publics, la prospection pétrolière, l'agriculture, ou tout simplement associé à la voiture ou au téléphone mobile dans la vie de tous les jours »[2].

Il garantira l'autonomie de l'UE vis-à-vis des USA et de la Russie dans ce domaine stratégique, notamment dans les applications militaires, et déploiera des facultés avancées par rapport à celles présentement offertes par le GPS des USA[2] ou GLONASS de la Russie.
Source:
http://fr.wikipedia.org/wiki/Galileo_(syst%C3%A8me_de_positionnement)