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NASA’s Scientific Balloon Program Reaches New Heights
For decades, NASA has released enormous scientific balloons into Earth’s atmosphere, miles above the altitude of commercial flights. The Balloon Program is currently preparing new missions bearing sensitive instruments, including one designed to investigate the birth of our universe and another with ballooning origins that will fly on the International Space Station.
NASA’s Primordial Inflation Polarization Explorer (PIPER), which will launch a series of test flights over the next few years, could confirm the theory that our nascent universe expanded by a trillion trillion (1024) times immediately following the big bang. This rapid inflation would have shaken the fabric of space-time, generating ripples called gravitational waves. These waves, in turn, should have produced detectable distortions in the cosmic microwave background (CMB), the earliest light in the universe lengthened into microwaves today by cosmic expansion. The patterns will appear in measurements of how the CMB light is organized, a property called polarization. Discovering twisting, pinwheel-like polarization patterns in the CMB will prove inflation occurred and take astrophysicists back to the brink of the big bang.
While Albert Einstein’s theories accurately describe gravity in today’s dilated cosmos, these large-scale physical laws did not apply when our universe was still the size of a hydrogen atom. To reconcile this disparity, PIPER will map the entire sky at four different frequencies, differentiating between twisting patterns in the CMB (indicating primordial gravitational waves) and different polarization signals due to interstellar dust. To maintain sensitivity, the telescope will fly immersed in a bucket of liquid helium the size of a hot tub but much cooler — nearly 457 degrees below zero Fahrenheit (minus 272 degrees Celsius) and close to absolute zero, the coldest temperature possible.
The PIPER mission was designed, built and tested at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, in collaboration with Johns Hopkins University in Baltimore, the University of British Columbia, Canada, the National Institute of Standards and Technology at Boulder, Colorado, and Cardiff University in Wales.
“We’re hoping to gain insight into our early universe as it expanded from subatomic size to larger than a planet in less than a second,” said Goddard’s Al Kogut, PIPER’s principal investigator. “Understanding inflation also augments our knowledge of high-energy particle physics, where the forces of nature act indistinguishably from one another.”
While PIPER prepares to observe roughly 20 miles above Earth, the latest iteration of the Cosmic Ray Energetics and Mass (CREAM) experiment is scheduled to launch to the space station in August. Although CREAM was balloon-borne during its six prior missions, the current payload will take the technology past Earth’s atmosphere and into space. CREAM will directly sample fast-moving matter from outside the solar system, called cosmic rays, from its new vantage point on the Japanese Experiment Module – Exposed Facility.
Cosmic rays are high-energy particles traveling at near the speed of light that constantly shower Earth. But precisely how they originate and accelerate through space requires more study, as does their abrupt decline at energies higher than 1,000 trillion electron volts. These particles have been boosted to more than 100 times the energy achievable by the world’s most powerful particle accelerator, the Large Hadron Collider at CERN.
CREAM — about the size of a refrigerator — will carry refurbished versions of the silicon charge detectors and ionization calorimeter from the previous balloon missions over Antarctica. The orbital edition of CREAM will contain two new instruments: the top/bottom counting detectors, contributed by Kyungpook National University in Daegu, South Korea, and a boronated scintillator detector to distinguish electrons from protons, constructed by a team from Goddard, Pennsylvania State University in University Park and Northern Kentucky University in Highland Heights.
The international collaboration, led by physicist Eun-Suk Seo at the University of Maryland, College Park, includes teams from numerous institutions in the United States as well as collaborating institutions in the Republic of Korea, Mexico and France. Overall management and integration of the experiment was led by NASA’s Wallops Flight Facility on Virginia’s Eastern Shore under the direction of Linda Thompson, the CREAM Project Manager.
According to co-investigator Jason Link, a University of Maryland, Baltimore County research scientist working at Goddard, CREAM’s evolution demonstrates the power of NASA’s Balloon Program as a developmental test bed for space instrumentation.
“A balloon mission can go from an idea in a scientist’s head to a flying payload in about five years,” Link said. “In fact, many scientists who design experiments for space missions get their start in ballooning. It’s a powerful training ground for researchers and engineers.”
As is true with any complex mission, things don’t always go as planned. Such was the case for the Balloon Experimental Twin Telescope for Infrared Interferometer (BETTII) experiment, intended to investigate cold objects emitting light in the far-infrared region of the electromagnetic spectrum.
BETTII launched on June 8 from NASA’s Columbia Scientific Balloon Facility in Palestine, Texas. Although nearly all the mission components functioned as they should, the payload detached from its parachute and fell 130,000 feet in 12 minutes as the flight ended the following day.
BETTII Principal Investigator Stephen Rinehart at Goddard estimates it will take several years to secure funding and rebuild the mission.
Designed, assembled and tested at Goddard in collaboration with the University of Maryland, Johns Hopkins University, Cardiff University, University College London and the Far-Infrared Interferometric Telescope Experiment team in Japan, BETTII is designed to examine lower infrared frequencies with unprecedented resolution. While optical telescopes like Hubble cannot see stars shrouded by thick dust clouds, far-infrared observations pierce the veil, revealing how these objects form and evolve.
“BETTII is one of the more complex balloon experiments ever flown,” Rinehart said. “As a research community, we understand that this risk is necessary for the scientific and technical progress we make with balloons.”
After all, just as risk and failure go hand in hand, so do risk and reward.
Provided by: NASA’s Goddard Space Flight Center
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When the sun goes dark: 5 questions answered about the solar eclipse
Editor’s note: A total solar eclipse will be visible across the U.S. on Monday, August 21. Shannon Schmoll, director of the Abrams Planetarium at Michigan State University, explains why and how it happens, and what we can learn from an eclipse.
How do we know when an eclipse is going to happen? How do we know in advance where it will be visible?
Solar eclipses happen when our view of the sun is blocked by the moon. When the moon lines up between the sun and Earth, the moon will cast a shadow onto Earth. This is what we on the ground observe as a solar eclipse.
We know when they’ll happen because over centuries astronomers have measured very precisely the motions of the Earth, moon and sun, including their orbital shapes, how the orbits precess and other parameters. With those data about the moon – and similar information about the Earth’s orbit around the sun – we can make mathematical models of their movements in relation to each other. Using those equations, we can calculate tables of data that can predict what we will see on Earth, depending on location, during an eclipse as well as when they will happen and how long they last. (The next major solar eclipses over the U.S. will be in 2023 and 2024.)
How often do eclipses happen?
A solar eclipse happens, on average, a couple times a year. The moon passes between the Earth and sun every 29 days, a time we call the “new moon” – when the moon is not visible in Earth’s nighttime sky. However, the moon’s orbit and the sun’s path in our sky don’t match up exactly, so at most of those new moon events, the moon appears above or below the sun.
Twice a year, though, there is a period where the moon and the sun line up with Earth – astronomers call this an eclipse season. It lasts about 34 days, long enough for the moon to complete a full orbit (and then some) of the Earth. During each eclipse season, there are at least two eclipses visible from some parts of the Earth. At the full moon, there will be a lunar eclipse, when the moon passes directly behind the Earth, resulting in a darker, reddish-colored moon. And at the new moon, there will be a solar eclipse, when the sun is blocked by the moon.
Can we learn anything from eclipse events, or are they really just oddities that happen in nature?
We can definitely learn things from eclipses. The outermost layer of the sun, known as the corona, is difficult to study because it’s less bright than the rest of the sun – so we have trouble seeing it amid the rest of the sun’s brightness.
When the moon blocks the sun, we can see the corona, the famous visual of the halo of light around the dark disk of the moon. Currently astronomers study this by creating an artificial eclipse with a mask built into special instruments on telescopes called coronagraphs. This is great, but doesn’t allow the best pictures. Eclipses give scientists opportunities to get more data to study the corona in depth.
We can also learn about Earth itself. In an area affected by an eclipse, the darkening of the sun leads to a sudden drop in temperature. NASA-funded studies during this eclipse will look at the effects from the eclipse on our atmosphere as well as what happens on land. Previous studies observed animal behavior during an eclipse in 2001 and noted some animals went through their night routines as the sun disappeared while others became nervous.
And we can learn about the whole universe. Less than 100 years ago, an eclipse proved a prediction Albert Einstein had made about gravity. That success helped make him a household name. In his general theory of relativity, Einstein had predicted that gravity could bend the path of light. The effect he predicted was very slight, so it would best be viewed as the light passed a very large celestial body as part of its travels across a very long distance of space.
Sir Arthur Eddington, an astronomer who helped further the study of general relativity and whose work is a major piece of our modern understanding of stars and black holes, used the darkness provided by a solar eclipse to look at the position of the stars’ light during the day, when it passed the sun. He then compared those positions to their known positions at night. He saw that the gravity of the sun had bent the path – exactly as, and in the precise amount that, Einstein had predicted.
How weird is it that the moon can basically exactly block out the sun?
It is very unusual that the moon and the sun just happen to be at the right distances and sizes to appear to have the same size in our sky. This allows the moon to perfectly block the sun’s disk, while also showing us the corona. Venus and Mercury, for instance, can also pass in front of the sun from our perspective. However, they appear as small specks moving across the sun.
What would someone standing on the moon see happen on Earth? Would Earth get dark?
If you were on the moon, you would be able to see the effects of the solar eclipse on Earth only if you were standing on the moon’s night side, the side facing the Earth. You would see a round shadow cast onto the Earth. This particular eclipse will first hit the Pacific Ocean, then move into Oregon, cross the U.S. to South Carolina and end in the Atlantic Ocean. This path the shadow takes is called the path of totality.
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New Horizons’ Next Target Just Got a Lot More Interesting
Could the next flyby target for NASA’s New Horizons spacecraft actually be two targets?
New Horizons scientists look to answer that question as they sort through new data gathered on the distant Kuiper Belt object (KBO) 2014 MU69, which the spacecraft will fly past on Jan. 1, 2019. That flyby will be the most distant in the history of space exploration, a billion miles beyond Pluto.
The ancient KBO, which is more than four billion miles (6.5 billion kilometers) from Earth, passed in front of a star on July 17, 2017. A handful of telescopes deployed by the New Horizons team in a remote part of Patagonia, Argentina were in the right place at the right time to catch its fleeting shadow — an event known as an occultation – and were able to capture important data to help mission flyby planners better determine the spacecraft trajectory and understand the size, shape, orbit and environment around MU69.
Based on these new occultation observations, team members say MU69 may not be not a lone spherical object, but suspect it could be an “extreme prolate spheroid” – think of a skinny football – or even a binary pair. The odd shape has scientists thinking two bodies may be orbiting very close together or even touching – what’s known as a close or contact binary – or perhaps they’re observing a single body with a large chunk taken out of it. The size of MU69 or its components also can be determined from these data. It appears to be no more than 20 miles (30 kilometers) long, or, if a binary, each about 9-12 miles (15-20 kilometers) in diameter.
“This new finding is simply spectacular. The shape of MU69 is truly provocative, and could mean another first for New Horizons going to a binary object in the Kuiper Belt,” said Alan Stern, mission principal investigator from the Southwest Research Institute (SwRI) in Boulder, Colorado. “I could not be happier with the occultation results, which promise a scientific bonanza for the flyby.”
The July 17 stellar occultation event that gathered these data was the third of a historic set of three ambitious occultation observations for New Horizons. The team used data from the Hubble Space Telescope and European Space Agency’s Gaia satellite to calculate and pinpoint where MU69 would cast a shadow on Earth’s surface. “Both of these space satellites were crucial to the success of the entire occultation campaign,” added Stern.
Said Marc Buie, the New Horizons co-investigator who led the observation campaign, “These exciting and puzzling results have already been key for our mission planning, but also add to the mysteries surrounding this target leading into the New Horizons encounter with MU69, now less than 17 months away.”
Provided by: NASA
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