São quase nulas as hipóteses de salvar a missão Fobos-Grunt lançada para Marte no passado dia 8 de Novembro, mas que ficou «presa» em órbita terrestre devido à falha na ignição do seu sistema de propulsão.
Os especialistas russos tentaram na última noite contactar a Fobos-Grunt mas sem sucesso. Assim, as probabilidades de salvar a missão são quase nulas apesar dos especialistas continuarem a tentar contactar a sonda.
O fracasso desta missão irá ter consequências na industria espacial russa com a demissão de várias lideranças.
Segundo o Comando Estratégico Espacial dos Estados Unidos, a Fobos-Grunt deverá reentrar na atmosfera a 26 de Novembro de 2011.
Imagem: Roscosmos
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Sugiro este artigo:
Salvaging Science from Stricken Mars Moon Probe: A Scientist’s View
http://www.space.com/13596-phobos-grunt-life-experiment-salvaged.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+spaceheadlines+%28SPACE.com+Headline+Feed%29&utm_content=Google+Feedfetcher
Without the Fregat upper stage, Grunt cannot travel to Phobos, yet if this powerful and massive stage were jettisoned, some less powerful, but functional, engines would be available for burns.
Would this be enough to send any of the components to a higher orbit? Probably a more important question for you at this point is, “What would be the point of that?”
Then, there is the LIFE biomodule, which we piggybacked in the Grunt mission simply to get it into interplanetary space for as long as possible, 34 months in the case of this mission.
By interplanetary space, we are talking about an environment in which space radiation is much more intense than it is in LEO, because above Earth orbit is the geomagnetosphere, the Van Allen belts, which trap charged particle radiation coming from deep space. There is an inner belt, extending from about 100 to 10,000 kilometers high, and an outer belt extending from 13,000 to 60,000 kilometers altitude.
Apollo 16 and Apollo 17 carried biology experiments known as Biostacks 1 and 2 beyond these belts (the moon is about 400,000 kilometers away). This was only for several days, however, for each mission, while most of the other tests of the survival of organisms in space have taken place in LEO.
Salvaging Phobos-LIFE
Link para a imagem: http://www.space.com/13596-phobos-grunt-life-experiment-salvaged.html?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed%3A+spaceheadlines+%28SPACE.com+Headline+Feed%29&utm_content=Google+Feedfetcher
The LIFE experiment, exploded view.
CREDIT: The Planetary Society
Since the Russians offered us the opportunity to take 10 biological species far beyond the geomagnetosphere by going to Phobos and back, we knew that we had an unprecedented opportunity to test whether organisms can survive for nearly three years in the interplanetary space environment.
To meet the objectives of Phobos LIFE, however, the return capsule, where the biomodule is mounted, actually would only need to fly beyond the radiation belts.
Consequently, it is tempting to think of a sort of consolation mission for Grunt, based on the idea of boosting the return capsule to an orbit with an altitude of 60,000 kilometers or more.
Then after a few years the capsule could be allowed to return to Earth as it was supposed to do on the way back from Phobos.
Or, maybe they could even leave it up for five or 10 years until it could be recovered another way. Since we’re looking at the ability of microbes to withstand space, the longer the better.
I don’t know if it is possible, nor how Roscosmos would feel about repurposing the mission, and of course I’m hoping for the best, because I’m nearly as excited about the Phobos sample return as I am about our much smaller experiment.
Nevertheless, should it turn out that control is restored, but the craft cannot get to Phobos due to fuel or engine issues, trying to salvage the science payload seems a whole lot better than allowing it to burn up with the fuel on re-entry.
“Or, maybe they could even leave it up for five or 10 years until it could be recovered another way. Since we’re looking at the ability of microbes to withstand space, the longer the better.”
Excelente ideia 🙂
A Spaceflightnow deveria começar a se informar melhor sobre estes assuntos. Como já disse a reentrada da Fobos-Grunt não será pior do que outras que aconteceram este ano. No caso do USA-193 (e admitindo como legítima a existência de propolente a bordo do satélite), o tanque encontrava-se no meio do corpo do satélite e em caso de reentrada poderia sobreviver. No caso da Fobos-Grunt os tanques estão expostose não foram fabricados para resistir à reentrada, como tal serão destruídos e com eles o propolente que lá se encontra. Isto é referido nas especificações técnicas da sonda.
No caso dos elementos radioacvtivos a bordo estamos a falar de 0,037 microgramas de Co-57. Não creio que esta quantidade seja preocupante.
Aqui vai informacao curiosa relativamente a uma reentrada:
“If Russia is unable to save the mission, the spacecraft would be subject to atmospheric drag, lowering its altitude until it fell back to Earth.
Phobos-Grunt is more massive than NASA’s Upper Atmospheric Research Satellite, which re-entered Earth’s atmosphere in late September. The highly-publicized re-entry, which had a 1-in-3,200 chance of striking a person, occurred over the Pacific Ocean.
A German scientific satellite fell to Earth in October with no reports of damage to property.
Phobos-Grunt still carries a full load of toxic hydrazine and nitrogen tetroxide propellant to reach Mars and enter orbit around the Red Planet. The propellant potentially makes Phobos-Grunt a greater threat to the public than either recent re-entry or the USA-193 spy satellite that was shot down by U.S. missile in 2008 to avoid an uncontrolled fall back to Earth.
U.S. government officials cited frozen hydrazine fuel in USA-193’s fuel tanks as the reason to worry about the satellite’s uncontrolled re-entry, leading the Bush administration to shoot down the spacecraft before it could naturally decay from orbit.
Russian officials quoted in the RIA Novosti news agency said Phobos-Grunt could remain in orbit for up to a month without a risk of falling.
The Phobos-Grunt propulsion system is derived from the Fregat upper stage, a hydrazine-fueled space tug that often places satellites in high-altitude orbits above Earth.
source: http://spaceflightnow.com/news/n1111/09phobosgrunt/
Obrigado 🙂
“Phobos-Grunt still carries a full load of toxic hydrazine and nitrogen tetroxide propellant to reach Mars and enter orbit around the Red Planet.”
têm que começar a meter um botão de auto-destruição nas sondas 🙂
A sonda e o seu sistema de propulsão ainda contêm todo o propolente que iria ser utilizado para enviar a sonda para Marte, para as manobras de correcção de trajectória, para as entrada em órbita de Marte, para as correcções orbitais, para a descida em Fobos, para a partida de Fobos, para o regresso à Terra e para as correcções de trajectória necessárias durante o regresso.
Eu pessoalmente não creio que todo este propolente consiga sobreviver à reentrada até porque os tanques estão expostos e não foram construídos para sobreviver a uma reentrada.
No entanto a bordo encontram-se duas pequenas cargas de Cobalto-57 radioactivo e não sei até que ponto estarão ou não protegidas. Para mim, será este o principal problema na reentrada.
Algumas partes da sonda podem sobreviver à reentrada. A sonda encontra-se numa inclinação orbial de cerca de 51,43º o que significa que pode cair em qualquer área da maior parte das zonas hibitadas do planeta.
ok. O problema será a parte radioactiva então 🙂
Pode fazer mossa na reentrada? 🙂
mossa???
mossa = estragos 🙂