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Sonntag, 6. Januar 2013 - 18:00 Uhr

Raumfahrt - Plasma-Schutzschilde für NASA-Raumschiffe?

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NASA Needs a Deflector Shield

The Solution to Cosmic Ray Bombardment

 We don’t need to expose NASA astronauts to cosmic rays. They’re already fantastic enough. Since the late ’50s,  NASA doctors and scientists have been concerned about our astronauts’ exposure to  radiation once out of the Earth’s protection. Now we know that exposure to cosmic rays can lead not just to cancer and to cataracts, but to  Alzheimer’s disease. Nor is there any material that can workably block those rays. It’s clear that any trip to deep space that will last longer than a few days or a week needs what the Starships have: a deflector shield. NASA Needs a Deflector Shield

Solar flares are dangerous enough. We know that the Apollo astronauts were extremely fortunate in the timing of their missions. A massive solar flare erupted just before the Apollo 17 mission that, had it occurred while astronauts were out and about collecting moon rock samples, would have killed them instantly, not at some later point in life. But ordinary shielding provides good protection against solar radiation, and NASA has experience integrating specially reinforced chambers into its spacecraft in case of solar flares. It also helped that the Apollo missions were relatively short.

Now, however, we are turning our attention to asteroid missions and, eventually, Mars. Material shielding against cosmic rays doesn’t yet exist in a way that is practical for spacecraft. In his 1977 book The High Frontier, addressing the challenge cosmic rays pose to space colonies – necessarily permanently located in space, and necessarily above the Earth’s protective magnetosphere – had to resort to surrounding the enormous craft with a six-foot thick crust of slag from the Moon. This fact gives a graphic idea of just how powerful cosmic rays are.
Clobberin' time for the Richards party

Clobberin’ time for the Richards party

Cosmic rays don’t derive from solar eruptions but from the general cosmic background. Their ultimate origin is not the periodic eruption of stellar surfaces, but supernovae and other massive cosmic events. The cosmic rays released by these events are of various kinds, but the type NASA is concerned with is composed of heavy atoms, such as iron atoms, that have been stripped of their electron shells and are now highly charged. Because of the number of their sources, they come from all directions; because of the vast number of sources, they are constant, and cannot be anticipated simply by observing an event like a solar eruption.

When we are told that nothing can stop high-energy, high-mass cosmic rays, this applies to conventional material shielding. Obviously, we are not being fried by these particles here on Earth, because, while the Earth lacks any material shield aside from the atmosphere itself, we are protected by the powerful magnetosphere.

The magnetosphere, discovered in 1958, is an enormous feature of our planet, reaching a quarter the distance of the Earth to the Moon. It is composed of ions and electrons trapped in the Earth’s magnetic field. A plasma, it has no fixed position but varies according to the solar wind. The side that faces the Sun, the magnetopause, “precedes” the Earth by as much as 70,000 kilometers.

Given this, the obvious solution to the problem of protecting humans in space is to do it the way we are protected on Earth. We know that it is possible to create an artificial magnetosphere. This was accomplished by Robert Winglee of the University of Washington, inventor of mini-magnetosphere plasma propulsion (M2P2) .

In the late ’90s there was great excitement about M2P2 as form of “space sail” – in other words, as a propulsion system – and the technology received funding from the NASA Institute for Advanced Concepts. A spacecraft enclosed in an M2P2 “bubble,” pushed along by the solar wind, should be able to reach Mars in as little as three months. The emphasis on M2P2 quieted as both Federal interest in a Mars mission andNASA Needs a Deflector Shield Federal funding for advanced physics fizzled. Ironically, in the small community of alternative space propulsion systems, this ion-deflecting system also seems to have been superceded by ion drive. Ion drive has already been used used successfully in space by the NASA Deep Space 1 and Dawn probes, as well as by the European Space Agency’s SMART-1 satellite.

M2P2 was always understood to have potential as a form of radiation shielding, but that application tended to remain in the background, almost as an asterisk, behind its propulsion application. It’s akin to the 19th century, when John D Rockefeller became fantastically wealthy as an oil baron while his refining process produced lakes of a useless by-product: gasoline. Perhaps now the time has at last come for M2P2′s radiation shielding potential to step into the foreground.

This will not be a slam-dunk. Launching an M2P2 system large enough to hold a spacecraft in a plasma “cavity” might not be easy, but it is likely to be easier than launching enough lead or concrete to encase the craft in six feet of concrete. Further, it ought to be a preferable strategy for permanently-stationed space habitats as well – not just the ambitious space colonies that are clearly the project of a future decade if not future generation, but also for space stations orbiting the Moon, Mars, or stationed at asteroids.

It should be easy, and relatively inexpensive, to test M2P2 in space. As such things  NASA Needs a Deflector Shieldare accounted, the issue has never been price. It has been, rather, a recognition of potential benefit. The advantages of M2P2 as a propulsion system have not disappeared, especially for deep space probes. Granted, though, that ion drive has been an unqualified success almost since the moment Deep Space 1 fired its thruster – and that, unlike M2P2, ion drive gives us a potential means to move a craft in any direction, both away from and toward the Sun, in one package. This still leaves us with the problem of shielding human beings.

If only astronauts exposed to cosmic rays simply gained super-powers, instead of developing Alzheimer’s. Alas, this is unlikely. Our only hope is to protect them. And who knows? One day some descendant of the M2P2 might protect space crews not only from cosmic rays, but from Romulan phasers.

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Quelle: The Guardian Express


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Sonntag, 6. Januar 2013 - 11:20 Uhr

Mars-Curiosity-Chroniken - Curiosity-News Sol 144-149

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'Snake River' Rock Feature Viewed by Curiosity Mars Rover

The sinuous rock feature in the lower center of this mosaic of images recorded by the NASA Mars rover Curiosity is called "Snake River." The images in the mosaic were taken by Curiosity's Navigation Camera during the 133rd Martian day, or sol, of the rover's mission on Mars (Dec. 20, 2012).

On Sol 147 (Jan. 3, 2013), Curiosity drove about 10 feet (3 meters) to get a closer look at Snake River for before proceeding to other nearby rocks.

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PASADENA, Calif. - After imaging during the holidays, NASA's Mars rover Curiosity resumed driving Jan. 3 and pulled within arm's reach of a sinuous rock feature called "Snake River."

Snake River is a thin curving line of darker rock cutting through flatter rocks and jutting above sand. Curiosity's science team plans to get a closer look at it before proceeding to other nearby rocks.

"It's one piece of the puzzle," said the mission's project scientist, John Grotzinger of the California Institute of Technology in Pasadena. "It has a crosscutting relationship to the surrounding rock and appears to have formed after the deposition of the layer that it transects."

The drive during the mission's 147th Martian day, or sol, on the Red Planet took Curiosity about 10 feet (3 meters) northwestward and brought the mission's total driving distance to 2,303 feet (702 meters). The rover is within a shallow depression called "Yellowknife Bay," which is a flatter and lighter-toned type of terrain from what the mission crossed during its first four months inside Gale Crater.

During a holiday break for the rover team, Curiosity stayed at a location within Yellowknife Bay from which the rover took images of its surroundings. The team is evaluating possible first targets for use of Curiosity's hammering drill in coming weeks. The drill will collect powdered samples from the interior of rocks for analysis by instruments inside the rover.

"We had no surprises over the holidays," said the mission's project manager, Richard Cook of NASA's Jet Propulsion Laboratory, Pasadena. "Now, Curiosity is back on the move. The area the rover is in looks good for our first drilling target."

NASA's Mars Science Laboratory Project is using Curiosity to assess whether areas inside Gale Crater ever offered a habitable environment for microbes. JPL, a division of Caltech, manages the project for NASA's Science Mission Directorate in Washington.

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This image was taken by Navcam: Left A (NAV_LEFT_A) onboard NASA's Mars rover Curiosity on Sol 144 (2013-01-01 02:09:28 UTC) .

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This image was taken by Navcam: Right A (NAV_RIGHT_A) onboard NASA's Mars rover Curiosity on Sol 147 (2013-01-04 04:35:20 UTC) .

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This image was taken by Navcam: Right A (NAV_RIGHT_A) onboard NASA's Mars rover Curiosity on Sol 147 (2013-01-04 04:35:56 UTC) .

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This image was taken by Navcam: Right A (NAV_RIGHT_A) onboard NASA's Mars rover Curiosity on Sol 147 (2013-01-04 04:37:06 UTC) .

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This image was taken by Navcam: Left A (NAV_LEFT_A) onboard NASA's Mars rover Curiosity on Sol 147 (2013-01-04 04:45:44 UTC) .

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This image was taken by Rear Hazcam: Right A (RHAZ_RIGHT_A) onboard NASA's Mars rover Curiosity on Sol 148 (2013-01-05 01:01:57 UTC) .

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This image was taken by Front Hazcam: Left A (FHAZ_LEFT_A) onboard NASA's Mars rover Curiosity on Sol 148 (2013-01-05 01:01:32 UTC) .

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This image was taken by Mars Hand Lens Imager (MAHLI) onboard NASA's Mars rover Curiosity on Sol 149 (2013-01-06 04:45:30 UTC) .

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This image was taken by Mars Hand Lens Imager (MAHLI) onboard NASA's Mars rover Curiosity on Sol 149 (2013-01-06 04:49:32 UTC) .

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This image was taken by Navcam: Right A (NAV_RIGHT_A) onboard NASA's Mars rover Curiosity on Sol 149 (2013-01-06 04:56:24 UTC) .

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This image was taken by Navcam: Right A (NAV_RIGHT_A) onboard NASA's Mars rover Curiosity on Sol 149 (2013-01-06 05:21:00 UTC) .

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This image was taken by Navcam: Left A (NAV_LEFT_A) onboard NASA's Mars rover Curiosity on Sol 149 (2013-01-06 04:56:24 UTC) .

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This image was taken by Navcam: Left A (NAV_LEFT_A) onboard NASA's Mars rover Curiosity on Sol 149 (2013-01-06 05:21:00 UTC) .

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This image was taken by Front Hazcam: Left A (FHAZ_LEFT_A) onboard NASA's Mars rover Curiosity on Sol 149 (2013-01-06 04:13:34 UTC) .

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Fotos: NASA


3216 Views

Samstag, 5. Januar 2013 - 11:49 Uhr

Astronomie - Sonnen-Flare vom Feinsten

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The sun celebrated New Year's Eve with an elegant solar eruption that, thanks to NASA, served to remind us just how puny we Earthlings are.

The space agency published a photo Friday morning comparing the size of Earth with this "relatively minor" eruption. The eruption (see video below), which occurred on Monday over the course of about four hours, extended about 160,000 miles out from the sun.

Our planet is about 7,900 miles in diameter, which means, the space agency said, the eruption was about 20 times the diameter of Earth.

"Magnetic forces drove the flow of plasma," NASA said, "but without sufficient force to overcome the sun’s gravity much of the plasma fell back into the sun."

This comparatively small eruption has nothing on some of the activity that has occurred on the sun as it heads toward the peak of an 11-year cycle.

Alex Young, associate director for science for the heliophysics division at Goddard Space Flight Center in Greenbelt, Md., previously spoke to the Los Angeles Times about the phenomenon.

"Solar activity has a cycle, minimum to maximum to minimum, and it's getting close to the peak of solar maximum," Young said.

The peak will occur sometime this year or in 2014, he said.

The size of a solar flare, Young noted, is a reasonable indicator of the strength and speed of a coronal mass ejection --  a violently released bubble of gas and magnetic fields. Among the categories of flares are C, M and X -- which, in general, translate to common, moderate and extreme.

An ejection, traveling at speeds of 1 million to 5 million miles per hour, takes about one to three days to reach Earth, he said.  Large, serious solar eruptions pose a danger to Earth's technology, as well as any spacecraft and astronauts that lie in their way. The blast of electromagnetic radiation can cause radio blackouts and, in more extreme cases, disrupt power.

Quelle: NASA


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Samstag, 5. Januar 2013 - 10:31 Uhr

Raumfahrt - Indien´s Raumfahrt-Pläne 2013

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MUMBAI: The first Indian astronaut to fly into space, Rakesh Sharma, on Friday admitted that after his landmark 'Saare Jahan Se Achcha Hindustan Hamara' reply to the then Prime Minister Indira Gandhi, he immediately realized that he had tripped up.

Sharma was replying to a student's question at the IIT-B Techfest on whether his response to her question 'How does India look from the space?' was deliberate or impromptu. The astronaut promptly said, "Why do you think it was not impromptu or original? "When answering to Mrs Gandhi's question, I must admit that I was having a great time in space. Fortunately, I couldn't see her and could only hear the audio channel. Perhaps that emboldened me to give, in my opinion, a rather smart answer to her question. Which I regretted immediately, when I heard her giggle and I said Oh my God! I have tripped up. You can't talk like that to a prime minister. But I do believe that India is Saare Jahan Se Achcha, not only visually but for what it stands for and our journey despite so much conflict and history. I think we still have our head above the water."

"When I was in school, it was our de facto number two national anthem. We sang it all the time. If you follow the words, I believe it describes the idea that is India accurately." said Sharma, who was one of the speakers at IIT-B's Techfest.

On whether China's launch of manned space mission is a setback for India, he said, "It is not a setback but a question of priorities. China had its priority clear. Isro announced a manned space programme, but we have not seen much progress. In India, what is lacking is the vision."

While speaking on 'Should India invest in manned space programme', Sharma slammed the government for not having a vision. "We need a different kind of fire, a vision, and I am sorry to say that it is lacking at the top echelons. Isro needs to send manned space programmes as robots cannot explore. It needs to be done before all resources are utilized. We need plans for international collaboration than competition," he said.

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The mission to Mars would take place as scheduled in October, director of ISRO’s Ahmedabad-based Physical Research Laboratory J.L. Goswami said here on Friday.

The work on the project was proceeding smoothly and the equipment for five experiments to be conducted during the mission should be ready by March for integration into the satellite, he told reporters on the sidelines of a panel discussion on payloads for the mission.

Dr. Goswami indicated that the mission would be launched with the help of ISRO’s workhorse PSLV –XL.

According to current plans, the launch is scheduled for around October 22. The satellite will initially orbit around the Earth for about a month to ensure that all the systems are functioning properly. Around November 26, it will exit the Earth’s orbit and embark on a journey to Mars, which is expected to last around 300 days.

Among the payloads is equipment to discover the presence of hydrogen or methane in the red planet’s atmosphere.

A major aim of the project is to try and take forward an international effort to solve several riddles that continue to confound scientists about Mars’ past. Previous studies had shown the presence of water on the planet some time in the past.

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Mars mission gets October, 2013 launch date deadline as India reaches out to the stars

India's space mission to Mars, expected to be launched in October, will look for signature of life and the reasons for loss of atmosphere on the red planet, a top scientist said here.

Work on the Mars Orbiter Mission, announced by Prime Minister Manmohan Singh in his Independence Day address last year, is going on full steam and equipment of the five experiments planned during the mission are expected to be delivered to ISRO in March.

"We should get the five payloads by March and we plan to start integrating them in the satellite from April," Jitendra Nath Goswami, director of the Physical Research Laboratory and closely involved with the Mars mission, said.

ISRO's trusted warhorse rocket PSLV-XL is expected to launch the mission some time in October from the spaceport Sriharikota which will first keep orbiting the earth, achieving the necessary velocity to escape the earth's gravitational pull.

As per existing plans, the satellite is expected to exit the Earth's orbit on November 26 and embark on the journey to Mars which is expected to last for around 300 days.

The scientists have drawn up plans to insert the satellite in an orbit around Mars on September 22 next year.

Once in the Martian orbit, the satellite will start taking pictures of the red planet with an onboard colour camera and infra-red spectrometer, while the Lyman-alpha photometer would measure atomic hydrogen in the Martian atmosphere.

"The previous missions to Mars have shown that there was water on the planet. We would want to know how and why the planet lost water and carbon dioxide," Goswami told reporters on the sidelines of the 100th Indian Science Congress here. "Nobody has done research why water was lost. We are trying to do things which were not precisely or exactly done," Goswami said.

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Updates on ISRO's Mars Orbiter Mission: five instruments to be delivered in March

 

Several news articles appeared in Indian media today about the upcoming launch of ISRO's Mars Orbiter Mission. It's the first time I've seen such detailed information about the spacecraft. There were two distinct articles appearing across numerous media outlets, so it must be a wire story or perhaps even an ISRO press release; I'm not sure how these things work in India. There isn't a release posted on ISRO's website, as far as I can find. Here's a summary of those, one printed in the Deccan Chronicle, Economic Times, Indian Express, and elsewhere, and the other posted at Parda Phash, IBN live, and other places.

The information comes out during the 100th Indian Science Congress, taking place this week in Kolkata.

  • Spacecraft facts:
    • Its main engine generates 440 Newtons of thrust.
    • Launch mass: 1350 kg.
    • It bears a single solar panel, 1.4 by 1.8 meters, producing 750W at Mars. [Note: This doesn't jibe with the single image that I have managed to find of the orbiter, posted below; that one appears to have a three-section panel, with each section possibly 1.4 by 1.8 meters. I can't explain the discrepancy.]
    • For attitude control it has four reaction wheels, eight 22-Newton thrusters.
  • Those are mostly pretty similar to Chandrayaan-1, except for the size of the solar panel. Chandrayaan-1 had a single 2.15-by-1.8-meter panel that generated 750W at the Moon. My guess is that the diagram below is correct and that the Mars spacecraft has a single solar array consisting of three panels 1.4 by 1.8 meters each, which would, together, manage to produce similar power at Mars that the single, larger panel did at the Moon.
  • Five instruments have been selected, including:
    • A color camera
    • A Thermal Infrared Imaging System
    • A Lyman-alpha photometer
    • An Exospheric Neutral Composition Analyzer
    • A Methane Sensor
  • The engineering model is complete, and the flight model should be completed in March.
  • ISRO expects instruments to be delivered in March for integration beginning in April.
  • Launch to Earth orbit will take place "some time in October."
  • The spacecraft will depart Earth orbit on November 26 and arrive at Mars on September 22, 2014.

The mission does not yet have a formal name ("Mangalyaan" is not it -- as far as I can tell, that name was made up by newspapers needing a name and following the "Chandrayaan" convention). For lack of a better one, though, I'll not change it in my previous posts until we find out what the formal name is going to be.

Jitendra Nath Goswami, director of ISRO's Physical Research Laboratory, is quoted as saying: "We are trying hard and by mid-October we are expecting to launch the Mars mission." And: "The mission has a very specific science objective as we want to study the atmosphere of Mars. This mission will explore things which have not been done previously by other countries." And: "The previous missions to Mars have shown that there was water on the planet. We would want to know how and why the planet lost water and carbon dioxide."

Although these goals sound similar to those of NASA's MAVEN, the instrument package is more general than MAVEN's -- color imaging, nighttime thermal infrared, and so on. Only the Exospheric Neutral Composition Analyzer seems to overlap with MAVEN. In any case, it's my impression that science is only a secondary goal for this mission. The primary goals are engineering ones: simply to succeed at launching a spacecraft on an Earth-to-Mars transfer orbit, successfully navigate it to Mars, successfully enter orbit at Mars, and operate it there at all would be major achievements for India, regardless of any scientific data return.

ISRO

Mangalyaan
Artist's concept of ISRO's Mangalyaan Mars orbiter.
Quelle: The Hindu / ISRO

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Freitag, 4. Januar 2013 - 23:05 Uhr

Raumfahrt - Bauen wir Kirk´s Enterprise?

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The United States has barely regained the ability to send unmanned cargo to the International Space Station via SpaceX’s Dragon capsule and a petition has been started to have the United States build a starship—no, we are not kidding. Entitled Build The Enterprise, or “BTE,” the website-based petition is working to have the White House build a spacecraft with capabilities similar to those of the vessel that Captain Kirk and company used to conduct their “five-year mission” in the television and movie franchise “Star Trek.”

The website details how to build such a vessel over the course of the next two decades. However, given the state of ever-pervasive financial issues that the United States is currently in, and the fact that NASA currently lacks even the ability to launch astronauts to low-Earth orbit, the proposal is not founded on reality, but rather emotion.

The website lacks the most basic understanding revolving around space flight and space history. In the section entitled “Our Space Problem,” a line appears to relegate the Apollo Program to a single lunar landing, stating that the United States has lost its way since the Moon landing of 1969. The Moon landings comprised six separate landings that stretched from 1969 through 1972.

BTE boasts that its Enterprise could get to Mars in 90 days and to the Moon in three. This is not too impressive when you consider the fact that the Apollo crews traveled to the Moon in the same length of time—in the 1960s—and that the VASIMR engine being developed by former NASA astronaut Franklin Chang-Diaz has been estimated at traveling to Mars in around 40 days.

This image appears on the website for Build The Enterprise and highlights the scale of the proposed spacecraft against landmarks and sea-going vessels. Image Credit: Build The Enterprise

The site’s author goes on to describe both the Skylab and International Space Station (ISS) as “yawners.” This juvenile language fills the website and further detracts from its credibility.

If those proposing BTE had looked into the basic facts and difficulty involved with constructing the ISS, which is about the size of a football field, they would quickly realize how constructing a spaceship that is more than 3,000 feet long is ludicrous. It took the efforts of sixteen different member nations on the International Space Station project nearly 13 years to build the station, so thinking that the U.S. can construct such a craft by itself in 20 years is just not based in reality.

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The Gen1 Enterprise will have three primary engines. These engines will be mounted on the aft ends of the three cylindrical-like hulls. As shown above, the main engine hull will contain the main engine and the two aux engine hulls will contain the two aux engines.

These three engines will all be ion propulsion type engines, sometimes also known as ion thrusters.  The thrust created by an ion propulsion engine is very small compared to conventional chemical rockets, but these engines have a very high specific impulse, meaning they use propellant very efficiency. This high propellant efficiency is achieved by accelerating the propellant to very high speeds.

Ion propulsion engines typically are left running constantly while a craft is traveling to some destination in space. Thus the engines provide constant acceleration to the spacecraft. While this acceleration is very small compared to the acceleration imparted by a chemical rocket, over time a small, constant acceleration can propel the spacecraft to very high speeds. It’s a case of the tortoise vs. the hare when it comes to comparing ion propulsion engines to chemical rocket engines. With ion propulsion engines that run continually it’s possible to reach far off places in a reasonably short amount of time.

As a goal, the Gen1 Enterprise will use .0001g constant acceleration when traveling outside of earth’s orbit. Since the Enterprise is built entirely in space, and never needs to be able to launch itself from earth into orbit, there is no need for the primary engines to ever use high thrust.

Ion propulsion engines are electrically powered and are thus classified as electric propulsion engines. As derived here, the main engine uses 1.5GWe of electrical power and each aux engine will use .5GWe of electrical power. This electrical power is supplied by nuclear reactors on the Gen1 Enterprise.

An example of an ion propulsion engine which has had considerable research is the VASIMR engine which is the brainchild of Costa Rican scientist and former astronaut Franklin Chang-Diaz. He is CEO of the Astra Rocket Company that is developing variations of the VASIMR. The Astra Rocket Company has a concept for a 200MWe VASIMR. This is near the range of what is needed for one of the .5GWe Aux Engines of the Gen1 Enterprise. (.5GWe = 500MWe.)

Here is a list of advantages for using ion propulsion engines in the Gen1 Enterprise over chemical rocket engines:

High specific impulse allows much less propellant to be carried onboard the ship, thus lowering its overall wet mass.

Safer than chemical rockets since there are no ignited materials in the engines.

The propellant gas used in the ion propulsion engines will be non-flammable and thus safer when stored in tanks and routed through pipes to the engines.

Very long engine life. Ideal for the Enterprise whose engines must last for decades.

Lends itself to being powered by a nuclear reactor that is used to generate electricity. Nuclear reactors have a very long life as a power source, which is a great fit for the Enterprise.

A low .0001g constant acceleration is so small that it does not interfere with the operation of the gravity wheel. The change in the gravity acting upon persons inside the wheel as the wheel spins is so slight that it will not be noticed-

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  • Quelle: BTE

3129 Views

Freitag, 4. Januar 2013 - 19:00 Uhr

Raumfahrt - History - MMU im Einsatz bei STS-41B-Challenger-Mission

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Dimensions:
Overall: 4 ft. 2 in. tall x 2 ft. 9 5/16 in. wide x 2 ft. 4 in. deep (127 x 84.61 x 71.12cm)

Materials:
Aluminum structure; internal electronics and metal components

The Manned Maneuvering Unit (MMU) is a backpack propulsion device that gave astronauts mobility for extravehicular activities outside the Space Shuttle. It enabled them to maneuver within the payload bay or fly some distance away without needing safety tethers anchored to the vehicle. The MMU had 24 small gaseous nitrogen thrusters and was operated with hand controllers on the arms of the unit.

On February 7, 1984, on Space Shuttle mission STS 41-B, astronaut Bruce McCandless tested this MMU, serial number 3. He made the first untethered spacewalk as he flew some 300 feet from the Shuttle. This MMU also flew on missions STS 41-C as the backup unit for the Solar Max satellite retrieval and STS 51-A as the prime unit for retrieving the Palapa communications satellite. Astronauts Bruce McCandless, Robert Stewart, James van Hoften, and Joseph Allen flew MMU #3 a total of 6 hours 29 minutes during these three 1984 missions. The MMUs were not used again. NASA transferred this one to the The National Air and Space Museum on the National Mall in Washington, D.C. in 2001.

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Artwork showing supportive equipment for contingency EVA
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Astronaut Bruce McCandless during an underwater test MMU/FSS in bldg 29 WETF
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EMU TV system test
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 Official portrait of Astronaut Bruce McCandless

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Crew portrait of the space shuttle mission 41-B crew
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Launch view of Challenger and the 41-B mission
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EVA by McCandless - Views of the extravehicular activity during STS 41-B

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Views of the extravehicular activity during STS 41-B
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Views of the extravehicular activity during STS 41-B
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 View of the Challenger from the fixed camera in McCandless's helmet
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View of Astronaut Bruc McCandless during EVA
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View of Astronaut Bruc McCandless during EVA
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Views of the extravehicular activity during STS 41-B
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Close-up view of Astronaut McCandless during his EVA
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  Views of the extravehicular activity during STS 41-B
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Views of the extravehicular activity of Astronaut Stewart during STS 41-B
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Views of the extravehicular activity during STS 41-B
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View of Astronaut Bruc McCandless during EVA
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 Views of the extravehicular activity during STS 41-B
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 Views of the extravehicular activity during STS 41-B
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 Views of the extravehicular activity during STS 41-B
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 Aerial view of the Challenger making approach for landing at KSC
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 Views of the Challenger after landing at Kennedy to end shuttle mission 41-B
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Fotos: NASA



3227 Views

Freitag, 4. Januar 2013 - 13:30 Uhr

Raumfahrt - ISS Foto-News von Astronaut Chris Hadfield

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Space Experiment - close-up of colloid particles responding to magnetic field, making a fluid behave like a solid. Chris Hadfield

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Ultrasound Lab - the rig we used to measure how Tom's heart is changing and adapting without gravity, like rapid aging.Chris Hadfield

3264 Views

Freitag, 4. Januar 2013 - 10:30 Uhr

Astronomie - Mars-Meteoriten 'Black Beauty' ist eine Klasse für sich

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A dark lump of rock found in the Moroccan desert in 2011 is a new type of Martian meteorite, say scientists.

Weighing 320g, the stone has been given the formal name Northwest Africa (NWA) 7034 - but is nicknamed "Black Beauty".

Its texture and chemistry set it apart from all previous objects picked up off the surface of Earth but known to originate on the Red Planet.

The researchers' analysis, reported in Science magazine, shows the meteorite to be just over two billion years old.

The study was led by Carl Agee from the University of New Mexico, US.

"It has some resemblance to the other Martian meteorites but it's also distinctly different in other respects," he told BBC News, "both in the way it just looks in hand sample, but also in its elemental composition."

There are just over 100 Martian meteorites currently in collections worldwide. They were all blasted off the Red Planet by some asteroid or cometary impact, and then spent millions of years travelling through space before falling to Earth.

Their discovery was mostly chance (few were seen in the act of falling) but their dark forms mean they will have caught the eye of meteorite hunters who scour desert sands and polar ice fields for rare rocks that can trade for tens of thousands of dollars.

Virtually all the Martian meteorites can be put in one of three classifications referred to as Shergotty, Nakhla, and Chassigny after key specimens. Scientists will often refer to these rocks simply as the SNC meteorites.

Prof Agee and colleagues argue that NWA 7034 now be put in its own class.

This rock is a basaltic breccia in character. It is made of a jumble of fragments that have been cemented back together in the high temperatures of a volcanic eruption. There are many examples of Moon meteorites that look this way, but no SNC ones.

Geochemically, NWA 7034 is dominated by alkali elements such as potassium and sodium. This is precisely what the robot rovers studying basalts down on the ground on Mars also see. This is not a trait seen in the SNC meteorites, interestingly.

Prof Agee's team also see much more water in the new meteorite - about 6,000 parts per million. That is about 10 times more water bound into the rock than is the case in the most water-rich SNC specimens.

This says something about the environment in which the rock formed, indicating there was a much greater abundance of water to interact with the basalt.

"This rock is from two billion years ago and a lot of the SNCs are from only about 200-400 million years ago," explained Prof Agee.

"And of course those most recent times on Mars have witnessed a cold, dry planet with a thin atmosphere. A lot of people believe that early Mars, on the other hand, was a lot warmer and a lot wetter, and maybe even a harbour for life.

"So, what happened in between? When did this transformation to drier conditions occur? Well, NWA 7034, because of its greater age, may be able to address those questions."

Researchers Identify Water Rich Meteorite Linked to Mars Crust

 
 

WASHINGTON -- NASA-funded researchers analyzing a small meteorite that may be the first discovered from the Martian surface or crust have found it contains 10 times more water than other Martian meteorites from unknown origins.

This new class of meteorite was found in 2011 in the Sahara Desert. Designated Northwest Africa (NWA) 7034, and nicknamed "Black Beauty," it weighs approximately 11 ounces (320 grams). After more than a year of intensive study, a team of U.S. scientists determined the meteorite formed 2.1 billion years ago during the beginning of the most recent geologic period on Mars, known as the Amazonian.

"The age of NWA 7034 is important because it is significantly older than most other Martian meteorites," said Mitch Schulte, program scientist for the Mars Exploration Program at NASA Headquarters in Washington. "We now have insight into a piece of Mars' history at a critical time in its evolution."

The meteorite is an excellent match for surface rocks and outcrops NASA has studied remotely via Mars rovers and Mars-orbiting satellites. NWA 7034's composition is different from any previously studied Martian meteorite. The research is published in Thursday's edition of Science Express.

"The contents of this meteorite may challenge many long held notions about Martian geology," said John Grunsfeld, associate administrator for NASA's Science Mission Directorate in Washington. "These findings also present an important reference frame for the Curiosity rover as it searches for reduced organics in the minerals exposed in the bedrock of Gale Crater."

NWA 7034 is made of cemented fragments of basalt, rock that forms from rapidly cooled lava. The fragments are primarily feldspar and pyroxene, most likely from volcanic activity. This unusual meteorite's chemistry matches that of the Martian crust as measured by NASA's Mars Exploration Rovers and Mars Odyssey Orbiter.

"This Martian meteorite has everything in its composition that you'd want in order to further our understanding of the Red Planet," said Carl Agee, leader of the analysis team and director and curator at the University of New Mexico's Institute of Meteoritics in Albuquerque. "This unique meteorite tells us what volcanism was like on Mars 2 billion years ago. It also gives us a glimpse of ancient surface and environmental conditions on Mars that no other meteorite has ever offered."

The research team included groups at the University of California at San Diego and the Carnegie Institution in Washington. Experiments were conducted to analyze mineral and chemical composition, age, and water content.

Researchers theorize the large amount of water contained in NWA 7034 may have originated from interaction of the rocks with water present in Mars' crust. The meteorite also has a different mixture of oxygen isotopes than has been found in other Martian meteorites, which could have resulted from interaction with the Martian atmosphere.

Most Martian meteorites are divided into three rock types, named after three meteorites; Shergotty, Nakhla, and Chassigny. These "SNC" meteorites currently number about 110. Their point of origin on Mars is not known and recent data from lander and orbiter missions suggest they are a mismatch for the Martian crust. Although NWA 7034 has similarities to the SNC meteorites, including the presence of macromolecular organic carbon, this new meteorite has many unique characteristics.

"The texture of the NWA meteorite is not like any of the SNC meteorites," said co-author Andrew Steele, who led the carbon analysis at the Carnegie Institution's Geophysical Laboratory. "This is an exciting measurement in Mars and planetary science. We now have more context than ever before to understanding where they may come from."

The research was funded by NASA's Cosmochemistry Program and Astrobiology Institute, part of the Planetary Science Division in the Science Mission Directorate at NASA Headquarters. The research also was supported by the New Mexico Space Grant Consortium in Las Cruces, and the National Science Foundation in Arlington, Va.

Quelle: NASA


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Freitag, 4. Januar 2013 - 10:00 Uhr

Raumfahrt - Dawn-News: Große Kollisionen zwischen Asteroiden übertragen kohlenstoffhaltige Material in das innere Sonnensystem.

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Vesta: Giant impacts delivered carbon

Large collisions between asteroids transferred carbonaceous material in the inner solar system.

The protoplanet Vesta has been witness to an eventful past: images taken by the framing camera onboard NASA’s space probe Dawn show two enormous craters in the southern hemisphere. The images were obtained during Dawn’s year-long visit to Vesta that ended in September 2012. These huge impacts not only altered Vesta’s shape, but also its surface composition. Scientists under the lead of the Max Planck Institute for Solar System Research (MPS) in Germany have shown that impacting small asteroids delivered dark, carbonaceous material to the protoplanet. In the early days of our solar system, similar events may have provided the inner planets such as Earth with carbon, an essential building block for organic molecules. These results were published in the November-December issue of the journal Icarus.

Vesta is remarkable in many respects. With a diameter of approximately 530 kilometers, Vesta is the one of the few protoplanets in our solar system still intact today. Like other protoplanets, Vesta underwent complete melting approximately 4.5 billion years ago. However, most of the volcanic activity on Vesta is thought to have ceased within a few million years making it a time capsule from the early solar system. Dawn observations of Vesta have shown a surface with diverse brightness variations and surface composition. There is bright material on Vesta that is as white as snow and dark material on Vesta as black as coal.

The enigmatic dark material holds the key to understanding the impact environment around Vesta early in its evolution. Research led by scientists at the MPS has shown that this dark material is not native to Vesta but was delivered by impacting asteroids. “The evidence suggests that the dark material on Vesta is rich in carbonaceous material and was brought there by collisions with smaller asteroids,” explains Prof. Dr. Vishnu Reddy from the MPS and the University of North Dakota, the lead author of the paper. In the journal Icarus, he and his colleagues now present the most comprehensive analysis of this material so far. Compositional analysis, mapping, and modeling of dark material distribution on Vesta suggests that it was delivered during the formation of giant impact basins on Vesta.

“First, we created a map showing the distribution of dark material on Vesta using the framing camera data and found something remarkable,” explains Dr. Lucille Le Corre from the MPS, one of the lead authors of the study. Dark material was preferentially spread around the edges of the giant impact basins in the southern hemisphere of Vesta suggesting a link to one of the two large impact basins. A closer examination showed that the dark material was most probably delivered during the formation of the older Veneneia basin when a slow impacting asteroid collided with Vesta. Dark material from this two to three billion year old basin was covered up by the impact that subsequently created the Rheasilvia basin. “We believe that the Veneneia basin was created by the first of two impacts two to three billion years ago,” says Reddy. In fact, impact modeling presented in the paper reproduces the distribution of dark material from such a low velocity impact.  

Evidence for dark material is also found in the HED meteorites that come from Vesta. Some of the meteorites show dark inclusions that are carbon-rich. Color spectra of dark material on Vesta are identical to these carbon-rich inclusions in HED meteorites. The link between dark material on Vesta and dark clasts in HED meteorites provides us with direct evidence that these meteorites are indeed from Vesta. “Our analysis of the dark material on Vesta and comparisons with laboratory studies of HED meteorites for the first time proves directly that these meteorites are fragments from Vesta”, says Le Corre.

“The aim of our efforts was not only to reconstruct Vesta’s history, but also to understand the conditions in the early solar system,” says Dr. Holger Sierks, co-investigator of the Dawn mission at the MPS.

The Dawn mission was launched approximately five years ago and entered orbit around Vesta on July 16th, 2011. In 2015, Dawn will arrive at its second destination, the dwarf planet Ceres, that like Vesta orbits the Sun between the orbits of Mars and Jupiter within the so-called asteroid belt. The Dawn mission to Vesta and Ceres is managed by NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, for NASA's Science Mission Directorate, Washington. The University of California, Los Angeles, is responsible for overall Dawn mission science. The Dawn framing cameras have been developed and built under the leadership of the Max Planck Institute for Solar System Research, Katlenburg-Lindau, Germany, with significant contributions by DLR German Aerospace Center, Institute of Planetary Research, Berlin, and in coordination with the Institute of Computer and Communication Network Engineering, Braunschweig. The Framing Camera project is funded by the Max Planck Society, DLR, and NASA/JPL.

Most of the dark, carbonaceous material on Vesta can be found on the rims of smaller craters ... credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

... or scattered in their surroundings. credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA

In this three-dimensional image of one of Vesta’s smaller craters, the dark material can be seen within the crater.

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Quelle: MPI für Sonnensystemforschung


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Freitag, 4. Januar 2013 - 09:45 Uhr

Astronomie - Keck Observatory entdeckt Pfannkuchen-Strukturen in Andromeda Galaxy

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This composite shows the alignment of the satellite galaxies of Andromeda, in relation to the view that we see from Earth (the top left panel shows a true-color image of the center of the Andromeda galaxy taken with the Canada France Hawaii Telescope). New distance measurements allow us to ascertain the three-dimensional positions of the satellite galaxies, which together with new velocity measurements, reveal their true nature as part of a gigantic rotating structure (side view: bottom left panel; front view: top right panel).-

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Surprise Pancake Structure in Andromeda Galaxy Upends Galactic Understanding

 

Kamuela, Hawaii – Astronomers using the Canada-France-Hawaii and W. M. Keck Observatory telescopes on the summit of Mauna Kea, Hawaii have been amazed to find a group of dwarf galaxies moving in unison in the vicinity of the Andromeda Galaxy. The structure of these small galaxies lies in a plane, analogous to the planets of the Solar System. Unexpectedly, they orbit the much larger Andromeda galaxy en masse, presenting a serious challenge to our ideas for the formation and evolution of all galaxies.

The findings are being reported on the cover the upcoming issue of the journal, Nature.

While Persian astronomers were the first to catalogue the Andromeda galaxy, only in the last five years that we have studied in exquisite detail the most distant suburbs of the Andromeda galaxy via the Pan-Andromeda Archaeological Survey (PAndAS), undertaken with the Canada-France-Hawaii Telescope and measured with the Keck Observatory, providing our first panoramic view of our closest large companion in the cosmos.

The study culminates many years of effort by an international team of scientists who have discovered a large number of the satellite galaxies, developed new techniques to measure their distances, and have used the Keck Observatory with colleagues to measure their radial velocities, or Doppler shifts (the speed of the galaxy relative to the Sun). While earlier work had hinted at the existence of this structure, the new study has demonstrated its existence to a high level of statistical confidence (99.998%).

The study reveals almost 30 dwarf galaxies orbiting the larger Andromeda galaxy in this regular, solar system-like plane. The astronomers’ expectations were that these smaller galaxies should be buzzing around randomly, like bees around a hive.

“This was completely unexpected,” said Geraint Lewis, one of the lead authors on the Nature publication. “The chance of this happening randomly is next to nothing.” The fact that astronomers now see that a majority of these little systems in fact contrive to map out an immensely large – approximately one million light years across – but extremely flattened structure, implies that this understanding is grossly incorrect. Either something about how these galaxies formed, or subsequently evolved, must have led them to trace out this peculiar, coherent, structure.

“We know of a number of galaxies that have experienced a collision, causing some of their stars to be expelled great distances, in sheets and tails.  However, it’s unlikely that kind of event explains what we are observing,” said R. Michael Rich, who led the Keck spectroscopy team.

While dwarf galaxies are not massive, they are the most numerous galaxy type in the universe: understanding this assemblage will undoubtedly shed new insight into the formation of galaxies at all masses.

For several decades, astronomers have used computer models to predict how dwarf galaxies should orbit large galaxies, and every time they found that dwarfs should be scattered randomly over the sky. Powered by supercomputers, these efforts have resulted in simulations of ever increasing fidelity. None of these computer-created universes have ever generated dwarfs arranged in a revolving plane like that observed in Andromeda.

“It is very exciting for my work to reveal such a strange structure,” said PhD student, Anthony Conn, whose research proved key to this study. “It has left us scratching our heads as to what it means.”

There have been similar claims for an extensive plane of dwarf galaxies about our own Milky Way Galaxy, with some claiming that the existence of such strange structures points to a failing in our understanding of the fundamental nature of the Universe.

“We don’t yet know where this is pointing us” said Rodrigo Ibata, lead author on the report. “It flies in the face of our ideas about galaxy formation, but it surely is very exciting.”

The W. M. Keck Observatory operates the two largest and most scientifically productive telescopes on Earth. The10-meter optical/infrared telescopes on the summit of Mauna Kea on the Island of Hawaii feature a suite of advanced instruments including imagers, multi-object spectrographs, high-resolution spectrographs, integral-field spectroscopy and a world-leading laser guide star adaptive optics system.  The Keck DEIMOS spectrograph used in the discovery was built by the University of California Observatories at UC Santa Cruz, and the Principal Investigator, Professor Sandra M. Faber, was recently honored with the National Medal of Science.  Keck Observatory is a private 501(c) 3 non-profit organization and a scientific partnership of the California Institute of Technology, the University of California and NASA.

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Quelle: Keck Observatory


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