How a 3 cm glass sphere could help scientists understand space weather

Solar flares and other types of space weather can wreak havoc with spaceflight and with telecommunications and other types of satellites orbiting the Earth. But, to date, scientists' ability to research ways to overcome that challenge has been severely limited. That's because experiments they conduct in laboratories here on Earth are affected by gravity in ways that are so different from conditions in space.

But a new study by UCLA physicists could, at last, help conquer that issue -- which could be a big step toward safeguarding humans (and equipment) during space expeditions, and to ensuring the proper functioning of satellites. The paper is published in Physical Review Letters.

The UCLA researchers effectively reproduced the type of gravity that exists on or near stars and other planets inside of a glass sphere measuring 3 centimeters in diameter (about 1.2 inches). To do so, they used sound waves to create a spherical gravitational field and generate plasma convection -- a process in which gas cools as it nears the surface of a body and then reheats and rises again as it nears the core -- creating a fluid current that in turn generates a magnetic current.

The achievement could help scientists overcome the limiting role of gravity in experiments that are intended to model convection that occurs in stars and other planets.

"People were so interested in trying to model spherical convection with laboratory experiments that they actually put an experiment in the space shuttle because they couldn't get a strong enough central force field on the ground," said Seth Putterman, a UCLA physics professor and the study's senior author. "What we showed is that our system of microwave-generated sound produced gravity so strong that Earth's gravity wasn't a factor. We don't need to go into space to do these experiments anymore."

UCLA researchers used microwaves to heat sulfur gas to 5,000 degrees Fahrenheit inside the glass sphere. The sound waves inside the ball acted like gravity, constraining movement of the hot, weakly ionized gas, known as plasma, into patterns that resemble the currents of plasma in stars.

"Sound fields act like gravity, at least when it comes to driving convection in gas," said John Koulakis, a UCLA project scientist and the study's first author. "With the use of microwave-generated sound in a spherical flask of hot plasma, we achieved a gravity field that is 1,000 times stronger than Earth's gravity."

On Earth's surface, hot gas rises because gravity holds denser, colder gas closer to the planet's center.

Indeed, the researchers found that hot, bright gas near the outer half of the sphere also moved outward toward the walls of the sphere. The strong, sustained gravity generated turbulence that resembled that seen near the Sun's surface. In the inner half of the sphere, the acoustic gravity changed direction and pointed outward, which causes hot gas to sink to the center. In the experiment, acoustic gravity naturally held the hottest plasma at the center of the sphere, where it also occurs in stars.

The ability to control and manipulate plasma in ways that mirror solar and planetary convection will help researchers understand and predict how solar weather affects spacecraft and satellite communications systems. Last year, for example, a solar storm knocked out 40 SpaceX satellites. The phenomenon has also been problematic for military technology: the formation of turbulent plasma around hypersonic missiles, for example, can interfere with weapons systems communications.

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Spaceflight: Microgravity analog culture profoundly affects microbial infection process in 3-D human tissue models

Infectious microbes have evolved sophisticated means to invade host cells, outwit the body's defenses and cause disease. While researchers have tried to puzzle out the complicated interactions between microorganisms and the host cells they infect, one facet of the disease process has often been overlooked -- the physical forces that impact host-pathogen interactions and disease outcomes.

In a new study, corresponding authors Cheryl Nickerson, Jennifer Barrila and their colleagues demonstrate that under low fluid shear force conditions that simulate those found in microgravity culture during spaceflight, the foodborne pathogen Salmonella infects 3-D models of human intestinal tissue at much higher levels, and induces unique alterations in gene expression.

This study advances previous work by the same team showing that physical forces of fluid shear acting on both the pathogen and host can transform the landscape of infection.

Understanding this subtle interplay of host and pathogen during infection is critical to ensuring astronaut health, particularly on extended space missions. Such research also sheds new light on the still largely mysterious processes of infection on earth, as low fluid shear forces are also found in certain tissues in our bodies that pathogens infect, including the intestinal tract.

While the team has extensively characterized the interaction between conventionally grown shake flask cultures of Salmonella Typhimurium and 3-D intestinal models, this study marks the first time that S. Typhimurium has been grown under the low fluid shear conditions of simulated microgravity and then used to infect a 3-D model of human intestinal epithelium co-cultured with macrophage immune cells, key cell types targeted by Salmonella during infection.

The 3-D co-culture intestinal model used in this study more faithfully replicates the structure and behavior of the same tissue within the human body and is more predictive of responses to infection, as compared with conventional laboratory cell cultures.

Results showed dramatic changes in gene expression of 3-D intestinal cells following infection with both wild-type and mutant S. Typhimurium strains grown under simulated microgravity conditions. Many of these changes occurred in genes known to be intimately involved with S. Typhimurium's prodigious ability to invade and colonize host cells and escape surveillance and destruction by the host's immune system.

"A major challenge limiting human exploration of space is the lack of a comprehensive understanding of the impact of space travel on crew health," Nickerson says. "This challenge will negatively impact both deep space exploration by professional astronauts, as well as civilians participating in the rapidly expanding commercial space market in low Earth orbit. Since microbes accompany humans wherever they travel and are essential for controlling the balance between health and disease, understanding the relationship between spaceflight, immune cell function, and microorganisms will be essential to understand infectious disease risk for humans."

Nickerson, who co-directed the new study with Jennifer Barrila, is a researcher in the Biodesign Center for Fundamental and Applied Microbiomics and is also a professor with ASU's School of Life Sciences. The research appears in the current issue of the journal Frontiers in Cellular and Infection Microbiology

Life-altering force

Life on earth has diversified into an almost incomprehensibly vast array of forms, evolving under wildly dissimilar environmental conditions. Yet one parameter has remained constant. Throughout the 3.7-billion-year history of life on earth, all living organisms evolved under, and respond to, the pull of Earth's gravity.

For more than 20 years, Nickerson has been a pioneer in exploring the effects of the reduced microgravity environment of spaceflight on a range of pathogenic microbes and the impact on interactions with human cells and animals they infect. She and her colleagues have doggedly pursued this research in both land-based and spaceflight settings, the results of which helped lay the foundation for the rapidly growing research field, mechanobiology of infectious disease, the study of how physical forces impact infection and disease outcomes.

Among their important findings is that the low fluid shear conditions associated with the reduced gravity environment of spaceflight and spaceflight analog culture are similar to those encountered by pathogens inside the infected host, and that these conditions can induce unique changes in the ability of pathogenic microbes like Salmonella to aggressively infect host cells and exacerbate disease, a property known as virulence.

The infectious agent explored in the new study, Salmonella Typhimurium, is a bacterial pathogen responsible for gastrointestinal disease in humans and animals. Salmonella is the leading cause of death from food-borne illness in the United States. According to the CDC, Salmonella bacteria cause about 1.35 million infections, 26,500 hospitalizations, and 420 deaths in the United States each year. Foods contaminated by the bacteria are the primary source for most of these illnesses.

Salmonella infection typically causes diarrhea, fever, and stomach cramps, beginning 6 hours to 6 days after infection. Illness from the disease usually lasts 4 to 7 days. In severe cases, hospitalization may be required.

'Shear' probability?

Cells in mammalian organisms, including humans, as well as the bacterial cells that infect them, are exposed to extracellular fluid flowing over their outer surfaces. Just as a gentle downstream current will affect the pebbles in the underlying streambed differently than a raging torrent, so the force of fluid gliding over cell surfaces can cause changes to affected cells. This liquid abrasion of cell surfaces is known as fluid shear.

Since spaceflight experiments are rare and access to the space research platform is currently limited, researchers often simulate the low fluid shear conditions that microbes encounter during culture in spaceflight by growing cells in liquid growth media within a device known as a rotating wall vessel bioreactor or RWV. As the cylindrical reactor rotates, cells are maintained in suspension, gently and continuously tumbling in their surrounding culture medium. This process mimics the low fluid shear conditions of microgravity that cells experience during culture in spaceflight.

The team has also shown that this fluid shear level is relevant to conditions that microbial cells encounter in the human intestine and other tissues during infection, triggering changes in gene expression that can help some pathogens better colonize host cells and evade the immune system's efforts to destroy them.

Portrait of an intruder

The study found significant changes in both gene expression and ability to infect 3-D intestinal models by Salmonella bacteria cultured in the RWV bioreactor. These experiments involved two S. Typhimurium strains, one unaltered or wild type strain and one mutant strain.

The mutant strain was otherwise identical to the wild type but lacked an important protein known as Hfq, a major stress response regulator in Salmonella. In earlier research, Nickerson and her team discovered that Hfq acts as a master regulator of Salmonella's infection process in both spaceflight and spaceflight analog culture. They later discovered additional pathogens that also use Hfq to regulate their responses to these same conditions.

Unexpectedly, in the current study, the hfq mutant strain was still able to attach, invade into, and survive within 3-D tissue models at levels comparable to the wild type strain. In agreement with this finding, many genes responsible for Salmonella's ability to colonize human cells, including those associated with cell adherence, motility, and invasion were still activated in the mutant strain under simulated microgravity conditions, despite the removal of Hfq.

From the host perspective, the 3-D intestinal co-culture model responded to Salmonella infection by upregulating genes involved in inflammation, tissue remodeling, and wound healing at higher levels when the bacteria were grown under simulated microgravity conditions prior to use in infection studies. This was observed for both wild type and hfq mutant strains of the pathogen.

Data from this new spaceflight analog study reinforces previous findings from the team's 2006, 2008 and 2010 Space Shuttle experiments. In particular, the 2010 flight experiment conducted aboard Space Shuttle Discovery, called STL-IMMUNE, used the same wild type strain of S. Typhimurium to infect a 3-D model of human intestinal tissue made from the same epithelial cells used in the new study.

Several commonalities were observed between host cell responses to infection in the new spaceflight analog study and those previously reported when infections took place in true spaceflight during the STL-IMMUNE experiment. These results further reinforce the RWV as a predictive ground-based spaceflight analogue culture system that mimics key aspects of microbial responses to true spaceflight culture.

"During STL-IMMUNE, we discovered that infection of a human 3-D intestinal epithelial model by Salmonella during spaceflight induced key transcriptional and proteomic biosignatures that were consistent with enhanced infection by the pathogen," Barrila says. "However, due to the technical challenges of performing in-flight infections, we could not quantify whether the bacteria were actually attaching and invading into the tissue at higher levels. The use of the RWV bioreactor as a spaceflight analog culture system in our current study has been a powerful tool which allowed us to explore this experimental question at a deeper level."

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Study explores effects of extended spaceflight on brain

Scientists from the U.S., Europe and Russia are part of a team releasing the results of a large collaborative study involving the effects of long duration spaceflight on the brain. It appears in the Proceedings of the National Academy of Sciences.

The researchers found that while all of the astronauts and cosmonauts they studied had a similar level of cerebrospinal fluid buildup in the brain, along with reduced space between the brain and the surrounding membrane at the top of the head, there was a noteworthy difference when it came to the Americans. They had more enlargement in the perivascular spaces in the brain, passages that serve as a cleaning system during sleep. That's something the researchers say warrants further investigation.

Donna Roberts, M.D., a neuroradiologist at the Medical University of South Carolina who helped lead the study, said a challenge when it comes to exploring the effects of spaceflight has been that there aren't many people in the U.S. who have traveled to space. Combining information about NASA astronauts with that of Russian cosmonauts and astronauts from the European Space Agency gave the study depth.

"By putting all our data together, we have a larger subject number. That's important when you do this type of study. When you're looking for statistical significance, you need to have larger numbers of subjects."

The study focused on 24 Americans, 13 Russians and a small, unspecified number of astronauts from the ESA. It used MRI scans of their brains before and after six months on the International Space Station to evaluate changes in the perivascular spaces.

Lead researcher Floris Wuyts, Ph.D., a professor at the University of Antwerp in Belgium, put the scope of the project in perspective. "I think it is one of the largest studies on space data, and for sure, one of the very few studies with NASA, ESA and Roscosmos data. It comprises data of almost 10% of all people who went into space." Roscosmos is the Russian space corporation.

Fellow researcher and neuroscientist Giuseppe Barisano, M.D., Ph.D., who works at the University of Southern California, said they looked for differences between the crews. "And in this analysis, we found an increased volume of fluid-filled channels in the brain after spaceflight that was more prominent in the NASA crew than in the Roscosmos crew."

Roberts explained what that might mean. "An important implication of our findings is that the volume of fluid-filled channels in the brain of astronauts is linked to the development of the spaceflight-associated neuro-ocular syndrome, a syndrome characterized by vision changes and whose mechanisms are still not completely clear."

But space physiologist Elena Tomilovskaya, Ph.D., of the Russian Academy of Sciences, said further study is needed to determine if there are clinical implications for future flights. "We need to understand how specific microgravity-countermeasure usage, exercise regimes, diet and other factors may play a role in the differences we found between crews."

Roberts agreed. "It is important not to speculate about pathology or brain health problems at this time. The observed effects are very small, but there are significant changes when we compare the post-flight scans with the preflight scans," she said.

The idea for the large study came about as the scientists gathered at annual meetings held by NASA and ESA. "Independently, we had previously reported similar changes in space crews at post-flight brain MRI, including enlargement of the cerebral ventricles. We discussed our findings and realized how valuable it would be to perform a joint analysis of our data. I would like to point out that Dr. Wuyts, in particular, was instrumental in organizing our group, which met regularly for two years to carry out this analysis," Roberts said."I believe it highlights the importance of international cooperation in understanding the effects of long-term spaceflight on the human body. In fact, we believe international cooperation in space medicine research is essential to ensure the safety of our crews as we return to the Moon and on to Mars."

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Spaceflight wreaks havoc on liver metabolism

The latest findings of a series of studies on mice that examined harmful effects caused by spending time in space show that gene expression related to liver metabolism is altered in response to the space environment. The benefit of these findings is that it may be possible to offset these changes with dietary supplementation during spaceflight.

Like other inhabitants of this planet, humans have evolved for life on Earth, not life in space or elsewhere. During spaceflight, the human body is exposed to a harmful environment, characterized by null or microgravity and high radiation levels. The liver is affected by spaceflight more than any other organ -- its crucial role in neutralizing harmful substances in the body means that spaceflight places incredible demands on the organ.

"Environmental stressors, such as high radiation and microgravity, induce a state of oxidative stress," explains Professor Iwao Ohtsu. "To deal with reactive oxygen and nitrogen compounds, the liver uses its limited resources, that is, antioxidant sulfur-containing compounds." The research team conducted novel experiments to compare liver gene expression levels between mice exposed to microgravity, mice exposed to simulated gravity on the International Space Station, and mice at ground level on Earth.

Mice that traveled to space and back had a lower antioxidant capacity because they had lower levels of the sulfur-containing compounds (e.g., ergothioneine, cysteine, and glutathione) that play a role in protecting cells by reducing reactive oxygen compounds, which limits free-radical damage. Overall, many indicators of oxidative stress were evident in the livers of these mice. In addition, there was greater expression of genes related to oxidative stress and sulfur metabolism pathways (which deplete levels of sulfur-containing antioxidant compounds) in mice that had been exposed to space.

Some effects, however, only occurred in mice exposed to microgravity. "Consequently, we were able to identify that some aspects of altered liver metabolism are counteracted by exposure to artificial gravity, whereas those caused by other environmental effects could be treated with alternative solutions, such as the addition of dietary supplements to astronauts' diets," says Professor Ohtsu.

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An experimental loop for simulating nuclear reactors in space

Nuclear thermal propulsion, which uses heat from nuclear reactions as fuel, could be used one day in human spaceflight, possibly even for missions to Mars. Its development, however, poses a challenge. The materials used must be able to withstand high heat and bombardment of high-energy particles on a regular basis.

Will Searight, a nuclear engineering doctoral student at penn State, is contributing to research that could make these advancements more feasible. He published findings from a preliminary design simulation in Fusion Science and Technology, a publication of the American Nuclear Society.

To better investigate nuclear thermal propulsion, Searight simulated a small-scale laboratory experiment known as a hydrogen test loop. The setup mimics a reactor's operation in space, where flowing hydrogen travels through?the core and propels the rocket -- at temperatures up to nearly 2,200 degrees Fahrenheit. Searight developed the simulation using dimensions from detailed drawings of tie tubes, the components that make up much of the test loop through which hydrogen flows. Industry partner Ultra Safe Nuclear Corporation (USNC) provided the drawings.

"Understanding how USNC's components behave in a hot hydrogen environment is crucial to bringing our rockets to space," Searight said. "We're thrilled to be working with one of the main reactor contractors for NASA's space nuclear propulsion project, which is seeking to produce a demonstration nuclear thermal propulsion engine within a decade."

Advised by Leigh Winfrey, associate professor and undergraduate program chair of nuclear engineering, Searight used Ansys Fluent, a modeling software, to design a simulation loop from a stainless steel pipe with an outer diameter of about two inches. In the model, the loop connects to a hydrogen pump and circulates hot hydrogen through a test section adjacent to a heating element.

Searight found that while consistent heating of hydrogen to 2,200 degrees Fahrenheit was possible, it was necessary to include a heating element directly above the test section to prevent a reduction in heating. Data collected from the modeling software showed that the flow of hydrogen through the test section was smooth and uniform, reducing uneven distribution of heat through the loop that could jeopardize the setup's safety and lifespan. Analysis of the results also verified that stainless steel would allow for more convenient and cost-effective construction of the loop.

"We are excited to take the first steps in developing a unique capability for extreme environment simulation at Penn State," Winfrey said. "This preliminary work will enable us to pursue research that could have a major impact on the future of space exploration."

With further research, Searight's preliminary work could enable expanded testing of materials that could one day be implemented to create faster, more efficient space travel using reactor-fueled rockets.

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All about Ultima: New Horizons flyby target is unlike anything explored in space

The Kuiper Belt lies in the so-called "third zone" of our solar system, beyond the terrestrial planets (inner zone) and gas giants (middle zone). This vast region contains billions of objects, including comets, dwarf planets like Pluto and "planetesimals" like Ultima Thule. The objects in this region are believed to be frozen in time -- relics left over from the formation of the solar system.

NASA's New Horizons spacecraft is set to fly by a distant "worldlet" 4 billion miles from the Sun in just six days, on New Year's Day 2019. The target, officially designated 2014 MU69, was nicknamed "Ultima Thule," a Latin phrase meaning "a place beyond the known world," after a public call for name recommendations. No spacecraft has ever explored such a distant world.

Ultima, as the flyby target is affectionately called by the New Horizons team, is orbiting in the heart of our solar system's Kuiper Belt, far beyond Neptune. The Kuiper Belt -- a collection of icy bodies ranging in size from dwarf planets like Pluto to smaller planetesimals like Ultima Thule (pronounced "ultima toolee") and even smaller bodies like comets -- are believed to be the building blocks of planets.

Ultima's nearly circular orbit indicates it originated at its current distance from the Sun. Scientists find its birthplace important for two reasons. First, because that means Ultima is an ancient sample of this distant portion of the solar system. Second, because temperatures this far from the Sun are barely above absolute zero -- mummifying temperatures that preserves Kuiper Belt objects -- they are essentially time capsules of the ancient past.

Marc Buie, New Horizons co-investigator from the Southwest Research Institute in Boulder, Colorado, and members of the New Horizons science team discovered Ultima using the Hubble Space Telescope in 2014. The object is so far and faint in all telescopes, little is known about the world beyond its location and orbit. In 2016, researchers determined it had a red color. In 2017, a NASA campaign using ground-based telescopes traced out its size -- just about 20 miles (30 kilometers) across -- and irregular shape when it passed in front of a star, an event called a "stellar occultation."

From its brightness and size, New Horizons team members have calculated Ultima's reflectivity, which is only about 10 percent, or about as dark as garden dirt. Beyond that, nothing else is known about it -- basic facts like its rotational period and whether or not it has moons are unknown.

"All that is about to dramatically change on New Year's Eve and New Year's Day," said New Horizons Principal Investigator Alan Stern, also of SwRI. "New Horizons will map Ultima, map its surface composition, determine how many moons it has and find out if it has rings or even an atmosphere. It will make other studies, too, such as measuring Ultima's temperature and perhaps even its mass. In the space of one 72-hour period, Ultima will be transformed from a pinpoint of light -- a dot in the distance -- to a fully explored world. It should be breathtaking!"

"New Horizons is performing observations at the frontier of planetary science," said Project Scientist Hal Weaver, of the Johns Hopkins University Applied Physics Laboratory in Laurel, Maryland, "and the entire team looks forward to unveiling the most distant and pristine object ever explored during a spacecraft flyby."

"From Ultima's orbit, we know that it is the most primordial object ever explored. I'm excited to see the surface features of this small world, particularly the craters on the surface," said Deputy Project Scientist Cathy Olkin, of SwRI. "Young craters could provide a window to see the composition of the subsurface of Ultima. Also by counting the number and impactors that have hit Ultima, we can learn about the number of small objects in the outer solar system."

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Lunar craters named in honor of Apollo 8

The Earthrise color photograph taken by astronaut William Anders. It depicts the moment that our shiny blue Earth came back into view as the spacecraft emerged out of the dark from behind the grey and barren Moon. This is arguably the most famous picture taken by Apollo 8. It became iconic and has been credited with starting the environmental movement. Two of the crates seen in this photo have just been named by the Working Group for Planetary System Nomenclature (WGPSN) of the International Astronomical Union.

The newly named craters are visible in the foreground of the iconic Earthrise colour photograph taken by astronaut William Anders. It depicts the moment that our shiny blue Earth came back into view as the spacecraft emerged out of the dark from behind the grey and barren Moon. This is arguably the most famous picture taken by Apollo 8. It became iconic and has been credited with starting the environmental movement.

Since the Moon is tidally locked to the Earth -- it always has the same side facing the Earth -- the Earth will never appear to rise above the surface to someone standing on the lunar farside. Orbiting around the Moon, however, gave the Apollo 8 astronauts, Frank Borman, James Lovell, and William Anders this stunning view, before they safely returned home to Earth.

The Apollo 8 mission took place from 21 to 27 December 1968. After completing 10 orbits around the Moon on Christmas Eve, broadcasting images back to Earth and giving live television transmissions, the crew returned to Earth and landed in the Pacific Ocean.

The Working Group for Planetary System Nomenclature (WGPSN) of the International Astronomical Union, who named the craters, is the authority responsible for the naming of planetary features in our Solar System. The two named craters were previously designated by letters.

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Voyager 1 fires up thrusters after 37 years

The Voyager team is able to use a set of four backup thrusters, dormant since 1980. They are located on the back side of the spacecraft in this orientation.

If you tried to start a car that's been sitting in a garage for decades, you might not expect the engine to respond. But a set of thrusters aboard the Voyager 1 spacecraft successfully fired up Wednesday after 37 years without use.

Voyager 1, NASA's farthest and fastest spacecraft, is the only human-made object in interstellar space, the environment between the stars. The spacecraft, which has been flying for 40 years, relies on small devices called thrusters to orient itself so it can communicate with Earth. These thrusters fire in tiny pulses, or "puffs," lasting mere milliseconds, to subtly rotate the spacecraft so that its antenna points at our planet. Now, the Voyager team is able to use a set of four backup thrusters, dormant since 1980.

"With these thrusters that are still functional after 37 years without use, we will be able to extend the life of the Voyager 1 spacecraft by two to three years," said Suzanne Dodd, project manager for Voyager at NASA's Jet Propulsion Laboratory, Pasadena, California.

Since 2014, engineers have noticed that the thrusters Voyager 1 has been using to orient the spacecraft, called "attitude control thrusters," have been degrading. Over time, the thrusters require more puffs to give off the same amount of energy. At 13 billion miles from Earth, there's no mechanic shop nearby to get a tune-up.

The Voyager team assembled a group of propulsion experts at NASA's Jet Propulsion Laboratory, Pasadena, California, to study the problem. Chris Jones, Robert Shotwell, Carl Guernsey and Todd Barber analyzed options and predicted how the spacecraft would respond in different scenarios. They agreed on an unusual solution: Try giving the job of orientation to a set of thrusters that had been asleep for 37 years.

"The Voyager flight team dug up decades-old data and examined the software that was coded in an outdated assembler language, to make sure we could safely test the thrusters," said Jones, chief engineer at JPL.

In the early days of the mission, Voyager 1 flew by Jupiter, Saturn, and important moons of each. To accurately fly by and point the spacecraft's instruments at a smorgasbord of targets, engineers used "trajectory correction maneuver," or TCM, thrusters that are identical in size and functionality to the attitude control thrusters, and are located on the back side of the spacecraft. But because Voyager 1's last planetary encounter was Saturn, the Voyager team hadn't needed to use the TCM thrusters since November 8, 1980. Back then, the TCM thrusters were used in a more continuous firing mode; they had never been used in the brief bursts necessary to orient the spacecraft.

All of Voyager's thrusters were developed by Aerojet Rocketdyne. The same kind of thruster, called the MR-103, flew on other NASA spacecraft as well, such as Cassini and Dawn.

On Tuesday, Nov. 28, 2017, Voyager engineers fired up the four TCM thrusters for the first time in 37 years and tested their ability to orient the spacecraft using 10-millisecond pulses. The team waited eagerly as the test results traveled through space, taking 19 hours and 35 minutes to reach an antenna in Goldstone, California, that is part of NASA's Deep Space Network.

Lo and behold, on Wednesday, Nov. 29, they learned the TCM thrusters worked perfectly -- and just as well as the attitude control thrusters.

"The Voyager team got more excited each time with each milestone in the thruster test. The mood was one of relief, joy and incredulity after witnessing these well-rested thrusters pick up the baton as if no time had passed at all," said Barber, a JPL propulsion engineer.

The plan going forward is to switch to the TCM thrusters in January. To make the change, Voyager has to turn on one heater per thruster, which requires power -- a limited resource for the aging mission. When there is no longer enough power to operate the heaters, the team will switch back to the attitude control thrusters.

The thruster test went so well, the team will likely do a similar test on the TCM thrusters for Voyager 2, the twin spacecraft of Voyager 1. The attitude control thrusters currently used for Voyager 2 are not yet as degraded as Voyager 1's, however.

Voyager 2 is also on course to enter interstellar space, likely within the next few years.

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Sputnik Launch 60 Years Ago Was Slow to Resonate With Americans

Soviet technician working on Sputnik 1, 1957

A Smithsonian Institution curator will argue at an event this week that when the Sputnik satellite launched 60 years ago on Oct. 4, it was "hyperbolic" to argue that the public immediately panicked about Soviet Union technological superiority.

Sputnik was the first space satellite and viewed as the beginning of the space race, when the Soviets and the United States used Earth orbit as an arena to test out space equipment and astronaut capabilities. The race culminated with the US putting astronauts on the moon beginning in 1969. While the Soviets targeted the moon as well, after several rocket failures they chose instead to focus on constructing space stations.

Since the disintegration of the Soviet Union in 1991, relations between the United States and Russia have been very different, with the nations collaborating extensively on the International Space Station. In late September, the two nations signed a cooperation agreement to work on Deep Space Gateway, a proposed space station near the moon that NASA plans for the 2020s, according to Russian space agency Roscosmos. The station could serve as a launching point for Mars missions in subsequent decades.

Despite the collaboration, the early years of the US-Soviet space race are often cited in the media. Accounts generally say that Sputnik set off a terror in the American public that resonated through the education system and immediately brought in support for the space race. But according to Michael Neufeld, a senior curator at the Smithsonian National Air and Space Museum's space history department, the short run after Sputnik showed little effect.

Neufeld will speak Oct. 4 at an event in Washington, DC called "The Space Race and the Origins of the Space Age," which will also feature representatives from Blue Origin, Raytheon Integrated Defense Systems, Fordham University, and the Washington Post.

"All public opinion polls showed that concern was not very high at the beginning," Neufeld told Seeker, "There was a lot of admiration for the Soviet achievement."

The public was more concerned about the crisis over Little Rock Central High School in Arkansas, when controversy erupted over nine black students enrolling in a formerly all-white school, Neufeld said. Segregation was still active in many parts of the American South. Under President Dwight D. Eisenhower's command, the Arkansas National Guard was mobilized to support integration.

More US concern arose in early November 1957 when the 1,000-pound Sputnik II carried the dog Laika into space, Neufeld said, which appeared to legitimize the Soviet claim that they could launch intercontinental ballistic missiles. On Dec. 6, 1957, the US responded with a rocket launch attempt of its own, which failed spectacularly on national television when the rocket carrying the Vanguard 1A satellite exploded shortly after launch.

"This failure, increasingly, it exacerbated both the tide of political and media criticism and anger over the US coming second," Neufeld said. "It also increased public opinion against the Eisenhower administration and concern over the nuclear arms race, rockets, and space."

Following the failure of Vanguard 1A, the United States swiftly responded by putting another rocket type up for launch: the Redstone missile, which successfully launched the Explorer 1 satellite on Jan. 31, 1958. The group that developed the missile was led by the famous Nazi-turned-US rocketeer Wernher Von Braun, who later was the chief architect of the Saturn V rocket that flew humans to the moon in the late 1960s.

The space race, according to Neufeld, actually began in 1955 when both the United States and the Soviet Union declared they were going to launch satellites for International Geophysical Year (1957-1958). At that time, the US considered using either the Vanguard or Redstone missiles. It was a government committee that chose the Vanguard due to the superior scientific capability advertised for its satellite. Eisenhower, Neufeld said, had little to do with the decision.

But as the effects of the Sputnik launch reverberated through the Eisenhower administration, it produced a significant reorganization of the US government. Eisenhower upgraded the president's science committee to make it report directly to the president. The predecessor agency to the military testing organization DARPA, called ARPA (the Advanced Research Project Agency), was created in February 1958 to try to pull together the competing space programs among different US military branches, Neufeld added.

But by the summer of 1959, the Army — due in part to its successful Redstone program — dominated most military space activity, with the exception of the Corona reconnaissance satellite program run by the Air Force and the Central Intelligence Agency.

NASA was created in 1958 to give the United States a civilian space agency in addition to its military space activities. This made the US the first nation in the world to place space activity under civilian control, Neufeld said.

A common narrative suggests the Sputnik launch led to the moon race of the 1960s, but Neufeld said the decision to go the moon was unique to John F. Kennedy, Eisenhower's successor as president. Kennedy was embarrassed by the failed US military invasion of Cuba in April 1961 and was looking for another way to quickly upstage the Soviets. He happened to choose space as the arena of competition. "If [Richard] Nixon had won the election, and it was a close election, he might have made a different decision," Neufeld said.

The US and the Soviet Union had a "moment of détente," Neufeld said, in the 1970s that led to collaboration on the Apollo-Soyuz mission of July 1975. Soviet cosmonauts and American astronauts met up orbit and conducted joint scientific experiments and press conferences. Soviet-US relations cooled again, he added, when the Soviet Union invaded Afghanistan in 1979, and the tension continued through both of Ronald Reagan’s presidential terms in the 1980s.

The situation changed when the Soviet Union collapsed in 1991, leading to US fears that Russian engineers would go to Iran, North Korea, or Pakistan and work on their military programs, Neufeld said. The Russian economy was falling apart, so the US hosted a series of paid shuttle flights to the Soviet-built space station, Mir. Russia also became an early and key partner in building the International Space Station, whose first pieces reached orbit in 1998.

"The International Space Station created this mutual dependency of the United States and Russia on each other in space, because they needed us to prop up their space station and human space program," Neufeld said.

Today, the United States depends on the Russians to transport astronauts to the orbiting complex. The US space shuttle program was retired in 2011, leaving only the Russians capable of launching astronauts to the ISS aboard its Soyuz rocket. US commercial crew vehicles will start replacing Soyuz flights in the next year or so.

"The US needs Russian rockets to get there, and the Russians need us to support the ISS — it's 75 percent funded by the US," Neufeld said. "Regardless of the political context creating crisis between [Russian President Vladimir] Putin and the US administration, so far the ISS has continued undisturbed by all of this because both countries need each other to run that program."

Read more at Seeker

NASA Posts Archive of Flight Test Videos on YouTube

A Lunar Lander Vehicle Flight with astronaut Neil Armstrong

Aviation geeks rejoice: There’s a whole new way to waste time.

NASA is marking 70 years of advanced aircraft testing by releasing a trove of old video from its Dryden Flight Research Center, the longtime home of the space agency’s atmospheric flight research.

The center, which was renamed for Apollo 11 commander Neil Armstrong in 2014, has posted dozens of short clips on its YouTube page this month. They include old films recently digitized as well as already-online video that has been moved to a more-accessible home, said Leslie Williams, a spokeswoman for the facility.

“The server that held those movies was becoming antiquated,” Williams said. “One of the best ways to preserve that video so other people could see it was to put it out on YouTube.”

The Armstrong center shares space with Edwards Air Force Base in the Mojave Desert east of Los Angeles. Established in 1946, it predates NASA and even the US Air Force, which was created in 1947 — the same year the first test flights were conducted.

It’s the home of the X-planes — high-speed, high-altitude experimental aircraft designed to push the limits of flight. They included the X-1, in which Chuck Yeager made the first supersonic flight in 1947, to the unmanned, 12-foot-long X-43, which hit nearly 7,000 mph in 2004. The latest, the X-57, is designed to test how well cleaner, quieter electric motors will work on manned aircraft.

The mostly-silent clips include footage of Armstrong himself, demonstrating a lunar lander trainer for reporters before his 1969 moon mission. You can watch test pilot Scott Crossfield descend from the bomb bay of a B-29 into the Douglas D-558 rocket plane slung underneath, shortly before it’s dropped from the mother ship. And there several clips of the X-15 space plane, in which several Air Force pilots earned astronaut wings for flights that topped 350,000 feet.

There were duds, too, like the X-3, a needle-nosed, stubby-winged craft nicknamed the Stiletto, which never lived up to its high-speed billing; and the XB-70 Valkyrie, a Mach 3 bomber design from the early 1960s. When the Pentagon passed on the Valkyrie, the two prototypes became test models for a future supersonic airliner.

And there are several lifting-body craft like the X-24, HL-10, and M2 series, which were steppingstones in the development of the space shuttles. It was a 1967 lifting-body crash, not included in this batch of video, that was featured in the opening credits of the 1970s television series “The Six Million Dollar Man.”

Read more at Seeker

Record 18,300 Apply for NASA Astronaut Training

More than 18,300 people have applied for 14 or fewer spots in NASA's next astronaut class, shattering the 1978 record of 8,000 applicants.

(In 1978, it had been nine years since the previous chance to apply to be an astronaut, and the space shuttle had recently been announced. Plus, it was the first official call for female applicants.)

The prospective astronauts all submitted their applications between Dec.14 and when the application period closed yesterday (Feb. 18) — and the total number is close to triple the applicants for NASA's most recent astronaut class, in 2012. (At the time, the 2012 application pool was the second largest ever at more than 6,300.)

"It's not at all surprising to me that so many Americans from diverse backgrounds want to personally contribute to blazing the trail on our journey to Mars," NASA Administrator Charles Bolden said in a statement. "A few exceptionally talented men and women will become the astronauts chosen in this group who will once again launch to space from U.S. soil on American-made spacecraft."

Bolden himself is a former astronaut, selected as one of a class of 19 in 1980.

Over the next 18 months, NASA's astronaut-selection board will narrow the applicants down, and the top applicants will interview at Johnson Space Center in Houston — ultimately, NASA will select a final set of eight to 14 astronaut candidates to begin training.

The training process will take about two years, and will include "training on spacecraft systems, spacewalking skills and teamwork, Russian language and other requisite skills," NASA officials said in the statement.

Ultimately, those who make it through the training will be assigned to either the International Space Station, NASA's Orion spacecraft, the Boeing CST-100 Starliner or the SpaceX Crew Dragon. Orion, currently in development to launch in the early 2020s on the new Space Launch System megarocket, will be able to support a crew of four for up to 21 days — habitat modules will be added for longer journeys, such as visiting Mars or deep space. Both the Starliner and Crew Dragon are in development aided by NASA's commercial crew program to bring four astronauts to the space station at a time.

Read more at Discovery News

NASA Remembers Fallen Astronauts, Pledges Mars Mission

The US space agency marked the 30th anniversary Thursday of the explosion of the space shuttle Challenger with a pledge to remember lost astronauts as it presses on toward Mars.

At the Kennedy Space Center in Florida, where the shuttle blasted off on January 28, 1986, singers outfitted in red and blue belted out the Star Spangled Banner for a crowd that included relatives and friends of the seven killed that day.

"The Challenger crew will forever be young, and will never be forgotten," said Bob Cabana, a former astronaut and director of the Kennedy Space Center.

"They continue to motivate us to explore."

A wreath-laying ceremony was planned for Arlington National Cemetery in Virginia as NASA commemorated the 24 US lives lost in space disasters and test flights over the years.

"As we undertake a journey to Mars, they will be with us. They have our eternal respect, love and gratitude," said a statement by NASA administrator Charles Bolden, a former astronaut.

"On this solemn occasion, we pause in our normal routines and remember."

Six NASA astronauts and Christa McAuliffe -- who would have been the first teacher in space -- were killed in the Challenger disaster, when the shuttle exploded 73 seconds after liftoff.

The cause was a failed booster engine, NASA said.

The other major shuttle accident was on February 1, 2003. Seven people died aboard the Columbia shuttle when it broke into pieces while re-entering Earth's atmosphere.

NASA said later that a piece of foam had come loose from the external tank during launch, and formed a hole in one of the shuttle's wings, causing it to break up 16 minutes before it was to have landed.

The US space agency also commemorated the three men who died in the Apollo 1 launch pad fire in 1967, before the nation ever made it to the moon.

"Remembering the crews today that we've lost, especially my best friend Ed White who perished in the Apollo 1 fire," astronaut Buzz Aldrin -- the second person to step foot on the Moon after American astronaut Neil Armstrong -- said on Twitter.

Bolden also recalled the 1967 loss of Mike Adams who died on an X-15 hypersonic rocket-powered aircraft, and others who perished in "test flights and aeronautics research throughout our history."

Read more at Discovery News

Space Fungus! Mold Attacks Space Station Plants

Four zinnia plants on the International Space Station are sickly or dead after mold was discovered in the Veggie experiment facility late December, according to NASA. The problem was immediately traced back to excessive water in the experiment, which was addressed. There are still three healthy plants that appear unaffected by the issue.

ISS commander and NASA astronaut Scott Kelly reported the mold to Mission Control Dec. 22 just as Veggie project manager Trent Smith was trying to manage the water problem. In pictures, Smith saw water on the plants a few days before. He told Discovery News he was trying to relay a command from NASA’s station operations team to increase fan speed in Veggie, but the mold developed before the command could be put through.

One solution was, on Christmas Eve, to designate Kelly “commander” of Veggie. Kelly now has more autonomy to make changes to Veggie’s conditions if he feels the plants need it.

Kelly is in the middle of a one-year mission on the station and was there when the first crops from Veggie, romaine lettuce, were harvested in August. “There’s nobody better positioned than Scott,” Smith told Discovery News, saying this decision should cut down on future time delays.

The zinnias on the International Space Station in December before the mold issue arose. The pillows in Veggie are labelled as such: Pillow A (top left), Pillow B (top right), Pillow C (middle left), Pillow D (middle right), Pillow E (bottom left) and Pillow F (bottom right).

Besides turning up the fan, sanitizing the experiment and wiping the excess water out of Veggie, Kelly bagged the moldy samples and put them in a freezer on station. They will be returned to Earth on the SpaceX 8 Dragon spacecraft later this year, when NASA will perform analysis to see what kind of mold it was. Any plants that die before SpaceX 8 departs will also be returned on that flight.

Each “pillow” of soil in Veggie was initially planted with two seeds, with the healthier of each pair culled early in their lifespans. A second plant -- which Smith dubbed the “stealth plant” -- sprang a little late in Pillow A (see caption in picture above), and investigators decided to leave it. Zinnias are expected to live about 60 days, but can last as long as 80, he added.

The problem was discovered about halfway through the plants’ lifespan. One plant in Pillow A died, while the “stealth plant” in that pillow survived and is growing well. The plants in Pillow B and D also died quickly, and the plant in Pillow E appears deathly ill as of Jan. 4, which was Day 49 of their cycle. The zinnias in Pillows C and F, however, still appear healthy. Smith said ground investigators continue to monitor the situation through photos and talking with Kelly.

Read more at Discovery News

Yearlong Mock Mars Mission to Test Mental Toll of Isolation

On Friday (Aug. 28), six scientists left the comforts of civilization, set to be gone for an entire year. Their mission will simulate what it might be like for astronauts journeying to Mars.

In the confines of a 36-foot-wide (11 meters) and 20-foot-high (6 m) solar-powered dome in a remote location on the island of Hawaii, the six team members will have to live together for 365 days. They will have no face-to-face contact with humans outside of the dome. This is the fourth and longest such mission carried out by the Space Exploration Analog and Simulation (HI-SEAS) program, and its goal is to find out how people will respond to the isolation that might accompany a mission to Mars.

“We hope that this upcoming mission will build on our current understanding of the social and psychological factors involved in long-duration space exploration,” Kim Binsted, principal investigator for HI-SEAS, said in a statement from the University of Hawaii.

The HI-SEAS project, which is based at University of Hawaii at Manoa, has put crews into the isolated mock Mars colony in four previous missions: two 4-month missions in 2013 and 2014, respectively, and an eight-month mission that ended in June 2015. During those previous trips, the crewmembers were allowed to leave the dome in spacesuits, occasionally engaging in outdoor activities like golfing, but mostly to do research in the local environment, the way members of a real Mars crew would.

MD2: settled into quarters. #domelife #hiseas #montana pic.twitter.com/MUWJJTTl9a — Carmel Johnston (@_CarmelJohnston) August 31, 2015

The team has a yearlong supply of food and water. The cuisine, which the team must be able to store for months at a time, is similar to what astronauts eat. Team member Sheyna Gifford tweeted on Saturday (Aug. 29) a picture of a quesadilla, with some peas and corn. She wrote, “First dinner in simulated space: The cheese & turkey quesadilla & all the veggies were all dehydrated 30 min. ago.”

The HI-SEAS habitat features a downstairs area with a lab, a kitchen, a common workspace, an exercise area, a dining room and a bathroom. Upstairs are six small bedrooms and a bathroom.

The current mission will “focus on crewmember cohesion and performance,” the statement said. “HI-SEAS researchers are working to develop effective team composition and support strategies to allow crews to successfully travel to Mars and back, an estimated three-year journey.”

Researchers will monitor the six crewmembers throughout the mission via cameras, body-movement trackers and other methods. Back in the real world, the researchers will gather data on “a wide range of cognitive, social and emotional factors that may impact team performance,” according to the statement.

Read more at Discovery News

Big Day for Little Pluto: Probe Makes Flyby

After tearing through space for 9.5 years, putting 3 billion miles on its odometer, NASA’s low-cost New Horizons spacecraft made it past Pluto, the last major unexplored piece of real estate in the solar system -- or so scientists hope.

Confirmation that New Horizons survived its brush by Pluto and its five known moons won’t come until 8:53 p.m. EDT Tuesday. But that didn’t stop the celebrations at New Horizons mission control center at the Johns Hopkins University Applied Physics Lab outside Baltimore.

“It’s truly a mark in human history,” said NASA’s associate administrator for science John Grunsfeld. “It’s been an incredible voyage.”

As New Horizons approached Pluto, scientists began realizing they were looking at a far more active world than initially imagined. The probe relayed its closest view yet on Monday before going into radio silence for the flyby. NASA released the image on Tuesday.

“What we’ve seen already from Pluto is that it’s a complex, interesting world,” Grunsfeld told reporters after the flyby.

With 99 percent of New Horizons flyby data still onboard the spacecraft, mission managers and scientists have a nervous wait ahead.

“Hopefully it survived the passage, we’re counting on that,” said lead scientist Alan Stern, with the Southwest Research Institute in Boulder, Colo.

New Horizons was on track to fly within 7,750 miles of Pluto at 7:49 a.m. EDT. Mission operations manager Alice Bowman said the latest data from the spacecraft showed it would arrive 72 seconds early, well within the targeted time for the planned encounter.

From Discovery News