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spaceflight (10)

The Slingshot Effect...

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An artist’s illustration of a spacecraft’s escape trajectory (bright white line) from our solar system into interstellar space. Credit: Mike Yukovlev Johns Hopkins Applied Physics Laboratory - Link 2 below

 

Topics: Astrophysics, Interstellar Travel, NASA, Spaceflight, Star Trek


Yes, an actual slingshot effect does exist.

As much a fan as I am of the Trek, this isn't it.

When a spacecraft in orbit about a primary body comes close to a moon that is orbiting the same primary body, there is an exchange of orbital energy and angular momentum between the spacecraft and the moon. The total orbital energy remains constant, so if the spacecraft gains orbital energy then the moon's orbital energy decreases. Orbital period, which is the time required to complete one orbit about the primary body, is proportional to orbital energy. Therefore, as the spacecraft's orbital period increases (the slingshot effect), the moon's orbital period decreases.

But because the spacecraft is much, much smaller than the moon, the effect on the spacecraft's orbit is much greater than on the moon's orbit. For example, the Cassini spacecraft weighs about 3,000 kilograms, whereas Titan, the largest of Saturn's moons, weighs about 1023 kilograms. The effect on Cassini is thus about 20 orders of magnitude greater than the effect on Titan is. [1]

 

*****


It would begin in the early 2030s, with a launch of a roughly half-ton nuclear-powered spacecraft on the world’s largest rocket, designed to go farther and faster than any human-made object has ever gone before. The probe would pass by Jupiter and perhaps later dive perilously close to the sun, in both cases to siphon a fraction of each object’s momentum, picking up speed to supercharge its escape. Then, with the sun and the major planets rapidly receding behind it, the craft would emerge from the haze of primordial dust that surrounds our star system, allowing it an unfiltered glimpse of the feeble all-sky glow from countless far-off galaxies. Forging ahead, it could fly by one or more of the icy, unexplored worlds now known to exist past Pluto. And gazing back, it could seek out the pale blue dot of Earth, looking for hints of our planet’s life that could be seen from nearby stars.

All this would be but a prelude, however, to what McNutt and other mission planners pitch as the probe’s core scientific purpose. About a decade after launch, it would pierce the heliosphere—a cocoonlike region around our solar system created by “winds” of particles flowing from our sun—to reach and study the cosmic rays and clouds of plasma that make up the “interstellar medium” that fills the dark spaces between the stars. Continuing its cruise, by the 2080s it could conceivably have traveled as far as 1,000 astronomical units (AU), or Earth-sun distances, from the solar system, achieving its primary objective at last: an unprecedented bird’s-eye view of the heliosphere that could revolutionize our understanding of our place in the cosmos. [2]

 

1. How does the slingshot effect (or gravity assist) work to change the orbit of a spacecraft? Scientific American, July 11, 2005
Jeremy B. Jones, Cassini Navigation Team Chief at NASA's Jet Propulsion Laboratory
2. Proposed Interstellar Mission Reaches for the Stars, One Generation at a Time
Scientific American, Lee Billings, November 2019

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Fossil Hunters...

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Lighter colors represent higher elevation in this image of Jezero Crater on Mars, the landing site for NASA's Mars 2020 mission. The oval indicates the landing ellipse, where the rover will be touching down on Mars.
Credits: NASA/JPL-Caltech/MSSS/JHU-APL/ESA

 

Topics: Astrobiology, Mars, NASA, Space Exploration, Spaceflight


Scientists with NASA's Mars 2020 rover have discovered what may be one of the best places to look for signs of ancient life in Jezero Crater, where the rover will land on Feb. 18, 2021.

A paper published today in the journal Icarus identifies distinct deposits of minerals called carbonates along the inner rim of Jezero, the site of a lake more than 3.5 billion years ago. On Earth, carbonates help form structures that are hardy enough to survive in fossil form for billions of years, including seashells, coral and some stromatolites — rocks formed on this planet by ancient microbial life along ancient shorelines, where sunlight and water were plentiful.

The possibility of stromatolite-like structures existing on Mars is why the concentration of carbonates tracing Jezero's shoreline like a bathtub ring makes the area a prime scientific hunting ground.

Mars 2020 is NASA's next-generation mission with a focus on astrobiology, or the study of life throughout the universe. Equipped with a new suite of scientific instruments, it aims to build on the discoveries of NASA's Curiosity, which found that parts of Mars could have supported microbial life billions of years ago. Mars 2020 will search for actual signs of past microbial life, taking rock core samples that will be deposited in metal tubes on the Martian surface. Future missions could return these samples to Earth for deeper study.

 

NASA's Mars 2020 Will Hunt for Microscopic Fossils, NASA

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It Takes a Village...

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This cutaway shows the interior of a 3D printed section of ESA's planned Moon Village.

 

Topics: ESA, Moon, NASA, Space Exploration, Spaceflight


We've all fantasized of visiting somewhere exotic. For most of us, that dream spot is somewhere on Earth. But for some, the ultimate must-see destination isn't on our planet at all.

NASA is currently planning a series of 37 rocket launches, both robotic and crewed, that will culminate with the 2028 deployment of the first components for along-term lunar base, according to recently leaked documents obtained by Ars Technica. An outpost on the Moon is surely an exciting prospect for both science geeks and prospective solar-system sightseers, but some believe NASA’s timeline is a too ambitious to be realistic.

However, unlike NASA, who not long ago adjusted their sights from Mars mission to a return to the Moon, the European Space Agency (ESA) has already spent almost five years quietly planning a permanent lunar settlement. And while building it may take a few decades, if done right, it could serve the entire world — sightseers included — for many more decades to come.

 

Moon Village: Humanity's first step toward a lunar colony?
Jake Parks, Astronomy Magazine

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Olympus Mons and Beyond...

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Olympus Mons, NASA/MOLA Science Team/ O. de Goursac, Adrian Lark

Topics: Mars, Planetary Science, Space Exploration, Spaceflight


Olympus Mons is the most extreme volcano in the solar system. Located in the Tharsis volcanic region, it's about the same size as the state of Arizona, according to NASA. Its height of 16 miles (25 kilometers) makes it nearly three times the height of Earth's Mount Everest, which is about 5.5 miles (8.9 km) high.

Olympus Mons is a gigantic shield volcano, which was formed after lava slowly crawled down its slopes. This means that the mountain is probably easy for future explorers to climb, as its average slope is only 5 percent. At its summit is a spectacular depression some 53 miles (85 km) wide, formed by magma chambers that lost lava (likely during an eruption) and collapsed.

Mars is a planet mostly shaped by wind these days, since the water evaporated as its atmosphere thinned. But we can see extensive evidence of past water, such as regions of "ghost dunes" found in Noctis Labyrinthus and Hellas basin. Researchers say these regions used to hold dunes that were tens of meters tall. Later, the dunes were flooded by lava or water, which preserved their bases while the tops eroded away.

Old dunes such as these show how winds used to flow on ancient Mars, which in turn gives climatologists some hints as to the ancient environment of the Red Planet. In an even more exciting twist, there could be microbes hiding in the sheltered areas of these dunes, safe from the radiation and wind that would otherwise sweep them away.

 

Touring Mars, Elizabeth Howell, Space.com

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Off-World Ventures...

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A scheme to beam solar power entails collecting sunlight and beaming it to Earth. An array of mirrored heliostats (conical structure) collects the sunlight, and a photovoltaic array (disk) converts it into electricity, which is then converted into a coherent microwave beam and sent to receivers almost anywhere in view on Earth. The image depicts the SPS-ALPHA, or Solar Power Satellite by means of Arbitrarily Large Phased Array.

 

Topics: Asteroids, Economics, Space Exploration, Spaceflight


An apparent confluence of political will and technological readiness has fans of humankind’s expansion beyond Earth hopeful that their dreams may soon become reality. Alongside a rise in missions to the Moon by agencies and private companies in the US, Europe, China, Japan, India, and Russia, commercial sectors are buzzing with related activities. And various governmental and nongovernmental bodies are strategizing about environmental, ethical, legal, sociological, and other issues of space utilization and colonization.

With interest in space travel growing—spurred in part by billionaire entrepreneurs such as Jeff Bezos and Elon Musk—enthusiasts say the time is right to figure out how to use space resources, including water, solar power, and lunar regolith. Doing so would expand space exploration, increase commercial activities in space, and lead to technological advances for humanity, says Angel Abbud-Madrid, director of the first graduate degree program in space resources, which he and colleagues launched last year at the Colorado School of Mines.

The only space resource exploited to date is the view of Earth from orbit for such applications as global positioning systems, weather prediction, communications, and science missions. A few years ago the prospect of mining asteroids for platinum and other metals to use on Earth was “the rage,” says George Sowers of the Colorado School of Mines. But the business case didn’t hold up. One exception might be rare-earth elements, but in the near to mid term, he says, “bringing stuff back to Earth is not economically viable.” For now, the focus has shifted to using space resources in situ.

Water is a primary target resource in space. Electrolyzed into hydrogen and oxygen, it becomes fuel that could replenish satellites in orbit and propel rockets for exploring the solar system and returning to Earth. Astronauts and space tourists could drink water, use it for gardening and hygiene, and shield themselves from ionizing radiation with meter-thick sheaths of it around habitats or spacecraft.

 

Prospect of off-planet outposts spurs interest in space resources
Toni Feder, Physics Today

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Shake, Rattle and Roar...

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SpaceX's Mars Starship prototype "Starhopper" hovers over its launchpad during a test flight in Boca Chica, Texas, U.S. August 27, 2019. REUTERS/Trevor Mahlmann

 

Topics: Mars, NASA, Space Exploration, Spaceflight


(Reuters) - SpaceX test-launched an early prototype of the company’s Mars rocket on Tuesday, unnerving residents near the Texas site and clearing another key hurdle in billionaire entrepreneur Elon Musk’s interplanetary ambitions.

After the launch, Musk congratulated engineers from SpaceX, short for Space Exploration Technologies Corp, and posted a photo of Starhopper touching down on its landing pad with billowing clouds of dust and sand rising from the ground.

“One day Starship will land on the rusty sands of Mars,” Musk tweeted.

The prototype, dubbed Starhopper, slowly rose about 500 feet (152 m) off its launch pad in Brownsville, Texas, and propelled itself some 650 feet (198 m) eastward onto an adjacent landing platform, completing a seemingly successful low-altitude test of SpaceX’s next-generation Raptor engine.

The Raptor is designed to power Musk’s forthcoming heavy-lift Starship rocket, a reusable two-stage booster taller than the Statue of Liberty that is expected to play a central role in Musk’s interplanetary space travel objectives, including missions to Mars.

 

SpaceX's Mars rocket prototype rattles nearby residents in Texas flight test
Joey Roulette, Reuters Science

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Half the Time...

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An illustration of a spacecraft powered by nuclear thermal propulsion. (Image: © NASA/Marshall)

 

Topics: Mars, NASA, Nuclear Fission, Space Exploration, Spaceflight


Humanity's next giant leap could be enabled by next-gen nuclear tech, NASA Administrator Jim Bridenstine said.

During the sixth meeting of the National Space Council (NSC) today (Aug. 20), the NASA chief lauded the potential of nuclear thermal propulsion, which would harness the heat thrown off by fission reactions to accelerate propellants such as hydrogen to tremendous speeds.

Spacecraft powered by such engines could conceivably reach Mars in just three to four months — about half the time of the fastest possible trip in a vehicle with traditional chemical propulsion, said NSC panelist Rex Geveden, the president and CEO of BWX Technologies Inc.

And that's a big deal for NASA, which is working to get astronauts to Mars in the 2030s.

"That is absolutely a game-changer for what NASA is trying to achieve," Bridenstine said. "That gives us an opportunity to really protect life, when we talk about the radiation dose when we travel between Earth and Mars."

 

Nuclear Propulsion Could Be 'Game-Changer' for Space Exploration, NASA Chief Says
Mike Wall, Space.com

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Legacy...

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APOLLO 11
Results from the Apollo 11 mission established key paradigms of lunar and planetary science. After a harrowing descent to the surface, Armstrong set the Eagle down on the cratered basaltic plains of Mare Tranquillitatis. Extravehicular activity was brief—just two and a half hours during that first mission—and included setting up surface experiments and exploring a small cluster of craters near the lunar module and Little West Crater some 60 meters away, as shown in figure 1. Aldrin’s iconic Apollo 11 bootprint photo revealed much about the lunar soil, including its fine-grained nature, its cohesiveness, and its ability to pack tightly together.

 

Topics: Apollo, Moon, NASA, Spaceflight


On 20 July 1969, Apollo 11 astronauts Neil Armstrong and Edwin “Buzz” Aldrin landed on the Moon while Michael Collins orbited in the command module Columbia. “Tranquility Base here. The Eagle has landed”became one of the most iconic statements of the Apollo experience and set the stage for five additional Apollo landings.

Each of the Apollo missions explored carefully selected landing sites and conducted a variety of experiments to probe the lunar interior and measure the solar wind. Well-trained astronauts made geologic observations and collected samples of rock and regolith, the impact-generated layer of debris that composes the lunar surface. Over a half century of study, the samples have revealed abundant information not only about the Moon’s origin and history but also about the workings of our solar system.

APOLLO 11

Results from the Apollo 11 mission established key paradigms of lunar and planetary science. After a harrowing descent to the surface, Armstrong set the Eagle down on the cratered basaltic plains of Mare Tranquillitatis. Extravehicular activity was brief—just two and a half hours during that first mission—and included setting up surface experiments and exploring a small cluster of craters near the lunar module and Little West Crater some 60 meters away, as shown in figure 1. Aldrin’s iconic Apollo 11 boot print photo revealed much about the lunar soil, including its fine-grained nature, its cohesiveness, and its ability to pack tightly together.

 

The scientific legacy of the Apollo program, Brad Jolliff, Mark Robinson, Physics Today

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Mars 2020...

When I test a vacuum, I just sprinkle oats all over the floor. When NASA tests one, you get this.

NASA/JPL-Caltech

 

Topics: Mars, NASA, Space Exploration, Spaceflight


NASA will leave no Martian rock unturned as it prepares the next Mars robot for the chaos of space travel and landing on the red planet.

Over the last two months, the Mars 2020 spacecraft has been subjected to a number of extreme tests designed to ensure it can withstand an intense rocket launch and the extremes of space. NASA's Jet Propulsion Laboratory has put the futuristic craft through "acoustic and thermal vacuum" testing -- and it has passed with flying colors.

The test involve blasting the spacecraft with sound levels as high as 150 decibels -- the type of levels you'd hear standing next to a jet at take-off -- to replicate the environment of a launch, according to Andy Rose, manager of JPL's environmental test facilities.

After the sound blast tests were performed six times, NASA put the Mars 2020 rover through a brutal test that replicates the vacuum of space. That required the spacecraft to be transported to the Space Simulator Facility and suspended in midair, as seen in the above image.

 

Mars 2020 spacecraft subjected to brutal tests as it prepares for launch, Jackson Ryan, CNET

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Twin Paradox...

Retired astronaut Mark Kelly (left) cracks a slight smile while posing with his identical twin brother, astronaut Scott Kelly (right). As part of NASA's Twins Study, Scott took a long trip to space, while Mark remained on Earth. Researchers then monitored how their bodies reacted to their differing environments. NASA

 

Topics: Astronaut, Astrophysics, Genetics, NASA, Spaceflight


Brothers compete. So in 2016, when astronaut Scott Kelly returned to Earth after spending a year in space, it must have really annoyed his identical twin brother — retired astronaut Mark Kelly — that Scott was two inches taller than when he left. However, Scott's temporary increase in height was not the only thing that changed during his trip.

As part of NASA's Twins Study, while Scott was in space, Mark went about his daily life on Earth. Over the course of the year-long mission, researchers tracked changes in both brothers' biological markers to pinpoint any variances. Because the twins share the same genetic code, researchers reasoned that any observed differences could tentatively — though not definitively — be linked to Scott's time aboard the International Space Station (ISS). This allowed them to take advantage of a unique opportunity and explore how an extended stay in space may impact the human body.

Based on their results, which were published this week in the journal Science, spaceflight can definitely trigger changes in the human body. But the vast majority of these changes disappear within just a few short months of returning to Earth.

Most notably, the researchers found that living in a microgravity environment can: damage DNA; impact the way thousands of individual genes are expressed; increase the length of telomeres (the shielding caps that protect the ends of our chromosomes); thicken artery walls; modify the microbiome; and increase inflammation — just to name a few.

"This is the dawn of human genomics in space," said Andrew Feinberg, a distinguished professor at Johns Hopkins University and one of the lead investigators for the Twins Study, in a press release. "We developed the methods for doing these types of human genomic studies, and we should be doing more research to draw conclusions about what happens to humans in space."

 

NASA's Twins Study: Spaceflight changes the human body, but only temporarily
Jake Parks, Astronomy

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