Monday, September 16, 2019

NASA's WFIRST Will Help Uncover the Universe's Fate

Scientists have discovered that a mysterious pressure dubbed "dark energy" makes up about 68% of the total energy content of the cosmos, but so far we don't know much more about it. Exploring the nature of dark energy is one of the primary reasons NASA is building the Wide Field Infrared Survey Telescope (WFIRST), a space telescope whose measurements will help illuminate the dark energy puzzle. With a better understanding of dark energy, we will have a better sense of the past and future evolution of the universe. Until the 20th century, most people believed that the universe was static, remaining essentially unchanged throughout eternity. When Einstein developed his general theory of relativity in 1915, describing how gravity acts across the fabric of space-time, he was puzzled to find that the theory indicated the cosmos must either expand or contract. He made changes to preserve a static universe, adding something he called the "cosmological constant," even though there was no evidence it actually existed. This mysterious force was supposed to counteract gravity to hold everything in place. However, as the 1920s were coming to a close, astronomer Georges Lemaitre, and then Edwin Hubble, made the startling discovery that with very few exceptions, galaxies are racing away from each other. The universe was far from static - it was ballooning outward. Consequently, if we imagine rewinding this expansion, there must have been a time when everything in the universe was almost impossibly hot and close together. The End of the Universe: Fire or Ice?


The Big Bang theory describes the expansion and evolution of the universe from this initial superhot, superdense state. Scientists theorized that gravity would eventually slow and possibly even completely reverse this expansion. If the universe had enough matter in it, gravity would overcome the expansion, and the universe would collapse in a fiery "Big Crunch."

If not, the expansion would never end - galaxies would grow farther and farther away until they pass the edge of the observable universe. Our distant descendants might have no knowledge of the existence of other galaxies since they would be too far away to be visible. Much of modern astronomy might one day be reduced to mere legend as the universe gradually fades to an icy black.

The Universe Isn't Just Expanding - It's Accelerating
Astronomers have measured the rate of expansion by using ground-based telescopes to study relatively nearby supernova explosions. The mystery escalated in 1998 when Hubble Space Telescope observations of more distant supernovae helped show that the universe actually expanded more slowly in the past than it does today. The expansion of the universe is not slowing down due to gravity, as everyone thought. It's speeding up.

Fast forward to today. While we still don't know what exactly is causing the acceleration, it has been given a name - dark energy. This mysterious pressure remained undiscovered for so long because it is so weak that gravity overpowers it on the scale of humans, planets and even the galaxy. It is present in the room with you as you read, within your very body, but gravity counteracts it so you don't go flying out of your seat. It is only on an intergalactic scale that dark energy becomes noticeable, acting like a sort of weak opposition to gravity.

What Is Dark Energy?
What exactly is dark energy? More is unknown than known, but theorists are chasing down a couple of possible explanations. Cosmic acceleration could be caused by a new energy component, which would require some adjustments to Einstein's theory of gravity - perhaps the cosmological constant, which Einstein called his biggest blunder, is real after all.

Alternatively, Einstein's theory of gravity may break down on cosmological scales. If this is the case, the theory will need to be replaced with a new one that incorporates the cosmic acceleration we have observed. Theorists still don't know what the correct explanation is, but WFIRST will help us find out.

WFIRST Will Illuminate Dark Energy
Previous missions have gathered some clues, but so far they haven't yielded results that strongly favor one explanation over another. With the same resolution as Hubble's cameras but a field of view that is 100 times larger, WFIRST will generate never-before-seen big pictures of the universe.

The new mission will advance the exploration of the dark energy mystery in ways that other telescopes can't by mapping how matter is structured and distributed throughout the cosmos, and also by measuring large numbers of distant supernovae. The results will indicate how dark energy acts across the universe, and whether and how it has changed over cosmic history.

The mission will use three survey methods to search for an explanation of dark energy. The High Latitude Spectroscopic Survey will measure accurate distances and positions of millions of galaxies using a "standard ruler" technique. Measuring how the distribution of galaxies varies with distance will give us a window into the evolution of dark energy over time. This study will connect the galaxies' distances with the echoes of sound waves just after the Big Bang and will test Einstein's theory of gravity over the age of the universe.

The High Latitude Imaging Survey will measure the shapes and distances of multitudes of galaxies and galaxy clusters. The immense gravity of massive objects warps space-time and causes more distant galaxies to appear distorted.

Observing the degree of distortion allows scientists to infer the distribution of mass throughout the cosmos. This includes all of the matter we can see directly, like planets and stars, as well as dark matter - another dark cosmic mystery which is visible only through its gravitational effects on normal matter. This survey will provide an independent measurement of the growth of large-scale structure in the universe and how dark energy has affected the cosmos.

WFIRST will also conduct a survey of one type of exploding star, building on the observations that led to the discovery of accelerated expansion. Type Ia supernovae occur when a white dwarf star explodes. Type Ia supernovae generally have the same absolute brightness at their peak, making them so-called "standard candles." That means astronomers can determine how far away they are by seeing how bright they look from Earth - and the farther they are, the dimmer they appear.

Astronomers will also look at the particular wavelengths of light coming from the supernovae to find out how fast the dying stars are moving away from us. By combining distances with brightness measurements, scientists will see how dark energy has evolved over time, providing a cross-check with the two high-latitude surveys.

"The WFIRST mission is unique in combining these three methods. It will lead to a very robust and rich interpretation of the effects of dark energy and will allow us to make a definite statement about the nature of dark energy," said Olivier Dore, a research scientist at NASA's Jet Propulsion Laboratory in Pasadena, California, and leader of the team planning the first two survey methods with WFIRST.

Discovering how dark energy has affected the universe's expansion in the past will shed some light on how it will influence the expansion in the future. If it continues to accelerate the universe's expansion, we may be destined to experience a "Big Rip." In this scenario, dark energy would eventually become dominant over the fundamental forces, causing everything that is currently bound together - galaxies, planets, people - to break apart. Exploring dark energy will allow us to investigate, and possibly even foresee, the universe's fate.

Sunday, September 15, 2019

Innovative model created for NASA to predict vitamin levels in spaceflight food

A team of food scientists at the University of Massachusetts Amherst has developed a groundbreaking, user-friendly mathematical model for NASA to help ensure that astronauts' food remains rich in nutrients during extended missions in space. The new research, published in the journal Food Chemistry, gives NASA a time-saving shortcut to predict the degradation of vitamins in spaceflight food over time and more accurately and efficiently schedule resupplying trips. The investigation was funded with a $982,685 grant from NASA. "There was no information available from literature to directly answer the questions and concerns that NASA had," says senior author Hang Xiao, professor and Clydesdale Scholar of Food Science. "We used real-time, real-life data in our study to train the mathematical model and to determine how predictive and reliable the model would be." The researchers painstakingly prepared and stored 3,000-plus pouches of spaceflight food according to the exact NASA recipes, thermal processing and storage specifications that are used for astronauts' meals on the International Space Station. Xiao and colleagues showed for the first time how thiamine (vitamin B1) degrades over two years in three crew menu options: brown rice, split pea soup and beef brisket. Xiao says it was "quite surprising" to find that while the brown rice and split pea soup stored at 20 C demonstrated resistance to thiamine degradation, the thiamine in beef brisket was much less stable, retaining only 3 percent of the vitamin after two years. "Proving the model was as simple as comparing these measured values from two years of storage to what was predicted as early as 12 months prior," says lead author Timothy Goulette, who was a UMass Amherst food science Ph.D. student during the study period.



The model was found to be able to predict vitamin degradation over time with "high precision," Xiao says, which will enable NASA to provide astronauts with the nutrition they need without resorting to the use of supplements.

"NASA will be able to use a minimal amount of data to quickly and accurately predict the vitamin content of a given food at any given time at a reasonable temperature," Goulette says. "The tool can be used for several applications, not just vitamins but other biological compounds."

The modeling tool will be especially important as NASA plans for the first human mission to Mars. "On their longest duration missions, the need to understand the nutritional content of their foods is paramount," Goulette explains.

The researchers note that NASA emphasizes the importance of getting nutrients from food naturally. "It's preferred for better health," Xiao says. "More and more research shows that your body handles a pill of vitamins differently from real food like pea soup."

Maintaining their nutrition through familiar food has benefits for space crews beyond their physical health, especially on longer missions, Goulette notes. "NASA wants to make sure the crew gets that psychological edge of having a connection to back home on Earth. There's a great emotional and psychological pull to food when nothing around you reminds you of home."

The UMass Amherst research team, which also included co-authors Micha Peleg, David Julian McClements, Eric Decker and Mark Normand, hypothesizes that the surprisingly higher rate of vitamin degradation in the beef may be related to the lipid oxidation of fat during thermal processing or over time.

"Different foods have different physical and chemical properties that make thiamine more or less stable," Goulette says.

Friday, September 13, 2019

Mars 2020 Spacecraft Comes Full Circle

Engineers took NASA's Mars 2020 for a spin on Aug. 29, 2019. The 2,300-pound (1,040-kilogram) Martian vehicle was rotated clockwise and counterclockwise at about 1 revolution per minute on what is called a spin table in the clean room of the Spacecraft Assembly Facility at NASA's Jet Propulsion Laboratory in Pasadena, California. The engineers were looking for the rover's center of gravity, or the point at which weight is evenly dispersed on all sides. Establishing the rover's center of gravity is a key part of the assembly process and helps ensure that the spacecraft travels smoothly from launch to entry, descent and landing on Mars as calculated. Engineers can add weights in order to help balance out the vehicle. In the end, they affixed nine tungsten weights totaling 44 pounds (20 kilograms) to the rover chassis at predetermined attachment points to get the center of gravity just right. "The spin table process is similar to how a gas station would balance a new tire before putting it on your car," said Lemil Cordero, Mars 2020 mass properties engineer at JPL. "We rotate the rover back and forth and look for asymmetries in its mass distribution. Then, similar to your gas station putting small weights on the tire's rim to bring it into balance, we'll put small balance masses on the rover in specific locations to get its center of gravity exactly where we want it." This was the assembled rover's first spin table test to determine its center of gravity; a second and final spin table test will occur at a NASA facility at Cape Canaveral in Florida next spring. JPL is building and will manage operations of the Mars 2020 rover for NASA. The rover will launch on a United Launch Alliance Atlas V rocket in July 2020 from Space Launch Complex 41 at Cape Canaveral. NASA's Launch Services Program, based at the agency's Kennedy Space Center in Florida, is responsible for launch management.


When the rover lands at Jezero Crater on Feb. 18, 2021, it will be the first spacecraft in the history of planetary exploration with the ability to accurately retarget its point of touchdown during the landing sequence.

Tuesday, September 10, 2019

Russian Space Agency to Test Modernized Fregat Upper Stage During Launch of Meteor Satellite in 2020

Russian state space corporation Roscosmos will test the modernized Fregat upper stage in 2020 during the blastoff of the Meteor-M meteorological satellite No. 2-3 from the Vostochny space centre, according to materials on the government procurement website. Earlier it was reported Roscosmos planned to create a modernized Fregat upper stage with a new control system by November 30, 2020, with 672 million rubles ($10.2 million) planned to be spent on this work. In July Russia successfully launched its Soyuz-2.1a carrier with Meridian military communications satellite from Plesetsk cosmodrome, located in Arkhangelsk region in Russia. The Meridian military communications satellite separated from Fregat upper stage and was placed into calculated orbit, the Russian Defence Ministry said.


Saturday, September 7, 2019

Firefly Aerospace pushes back first launch to 2020

Firefly Aerospace, one of several new rocket companies working on orbital launch services, has pushed back its first launch to early 2020 due to supplier delays. "We were trying for this year, but won't get there," Eric Salwan, Firefly's director of commercial business development told UPI. "Primarily, we are having issues with a few externally sourced components, such as the flight termination system." Issues include late delivery of components and testing or qualifying them for launch, he said. "We are on very solid ground in terms of our funding. No change there." Firefly said in February it had $1.3 billion in launch business lined up. It has been funded by Noosphere Ventures, the strategic venture arm of Noosphere Global. A leading investor in Noosphere is Ukrainian technologist and investor Max Polyakov. Since that time, at least one potential competitor, rocket startup Vector Launch, based in Tucson, Ariz., said it was "undertaking a pause of operations." Employees of Vector said they were being laid off. In an effort to minimize delays caused by suppliers, Firefly says 90 percent of its new Alpha rocket will be made in house. It currently builds the rocket at its headquarters near Austin, Texas. "The delay we are experiencing is why we want to make most of the rocket ourselves," Salwan said. Eventually, the company plans to build a rocket plant near Kennedy Space Center in Florida. It also is renovating two old launch pads, one at Cape Canaveral Air Force Station in Florida and one at Vandenberg Air Force Base in California. Space Florida, the state's marketing and development agency for space, is seeking $18.9 million in state funding for Firefly's operation, which is expected to support 239 jobs in Florida with anticipated annual average salaries of $70,000.


Dale Ketcham, a vice president with Space Florida, said Wednesday the agency has full confidence in Firefly.

"They're like every other company that is trying to put something into orbit. It takes time and there are usually delays," Ketcham said. "We don't hand out the state's money easily. We don't guarantee any company that comes here will be successful, but so far we are pretty good at picking winners."

Firefly Aerospace is part of a cluster of companies that have kicked off a new chapter of space exploration in Florida. Other companies with major facilities in the state include SpaceX, Jeff Bezos' Blue Origin and satellite manufacturer OneWeb.

Firefly will make smaller orbital rockets across the street from OneWeb's new satellite plant and near Blue Origin's factory for its larger New Glenn rockets. Firefly intends to offer relatively inexpensive launches for small satellites.

The company also plans a bigger rocket, Firefly Beta, and possibly a space plane, Firefly Gamma. It previously told Space Florida that it plans to invest $52 million into its plant and new launchpad facilities.