vendredi 26 avril 2019

Mystery of the Universe’s Expansion Rate Widens With New Hubble Data













NASA - Hubble Space Telescope (HST) patch.

April 26, 2019

Astronomers using NASA's Hubble Space Telescope say they have crossed an important threshold in revealing a discrepancy between the two key techniques for measuring the universe's expansion rate. The recent study strengthens the case that new theories may be needed to explain the forces that have shaped the cosmos.

A brief recap: The universe is getting bigger every second. The space between galaxies is stretching, like dough rising in the oven. But how fast is the universe expanding? As Hubble and other telescopes seek to answer this question, they have run into an intriguing difference between what scientists predict and what they observe.

Hubble Space Telescope (HST). Animation Credits: NASA/ESA

Hubble measurements suggest a faster expansion rate in the modern universe than expected, based on how the universe appeared more than 13 billion years ago. These measurements of the early universe come from the European Space Agency's Planck satellite. This discrepancy has been identified in scientific papers over the last several years, but it has been unclear whether differences in measurement techniques are to blame, or whether the difference could result from unlucky measurements.

The latest Hubble data lower the possibility that the discrepancy is only a fluke to 1 in 100,000. This is a significant gain from an earlier estimate, less than a year ago, of a chance of 1 in 3,000.

These most precise Hubble measurements to date bolster the idea that new physics may be needed to explain the mismatch.

"The Hubble tension between the early and late universe may be the most exciting development in cosmology in decades," said lead researcher and Nobel laureate Adam Riess of the Space Telescope Science Institute (STScI) and Johns Hopkins University, in Baltimore, Maryland. "This mismatch has been growing and has now reached a point that is really impossible to dismiss as a fluke. This disparity could not plausibly occur just by chance."

Tightening the bolts on the 'cosmic distance ladder'

Scientists use a "cosmic distance ladder" to determine how far away things are in the universe. This method depends on making accurate measurements of distances to nearby galaxies and then moving to galaxies farther and farther away, using their stars as milepost markers. Astronomers use these values, along with other measurements of the galaxies' light that reddens as it passes through a stretching universe, to calculate how fast the cosmos expands with time, a value known as the Hubble constant. Riess and his SH0ES (Supernovae H0 for the Equation of State) team have been on a quest since 2005 to refine those distance measurements with Hubble and fine-tune the Hubble constant.

In this new study, astronomers used Hubble to observe 70 pulsating stars called Cepheid variables in the Large Magellanic Cloud. The observations helped the astronomers "rebuild" the distance ladder by improving the comparison between those Cepheids and their more distant cousins in the galactic hosts of supernovas. Riess's team reduced the uncertainty in their Hubble constant value to 1.9% from an earlier estimate of 2.2%.


Image above: This is a ground-based telescope's view of the Large Magellanic Cloud, a satellite galaxy of our Milky Way. The inset image, taken by the Hubble Space Telescope, reveals one of many star clusters scattered throughout the dwarf galaxy. The cluster members include a special class of pulsating star called a Cepheid variable, which brightens and dims at a predictable rate that corresponds to its intrinsic brightness. Once astronomers determine that value, they can measure the light from these stars to calculate an accurate distance to the galaxy. When the new Hubble observations are correlated with an independent distance measurement technique to the Large Magellanic Cloud (using straightforward trigonometry), the researchers were able to strengthen the foundation of the so-called "cosmic distance ladder." This "fine-tuning" has significantly improved the accuracy of the rate at which the universe is expanding, called the Hubble constant. Image Credits: NASA, ESA, A. Riess (STScI/JHU) and Palomar Digitized Sky Survey.

As the team's measurements have become more precise, their calculation of the Hubble constant has remained at odds with the expected value derived from observations of the early universe's expansion. Those measurements were made by Planck, which maps the cosmic microwave background, a relic afterglow from 380,000 years after the big bang.

The measurements have been thoroughly vetted, so astronomers cannot currently dismiss the gap between the two results as due to an error in any single measurement or method. Both values have been tested multiple ways.

"This is not just two experiments disagreeing," Riess explained. "We are measuring something fundamentally different. One is a measurement of how fast the universe is expanding today, as we see it. The other is a prediction based on the physics of the early universe and on measurements of how fast it ought to be expanding. If these values don't agree, there becomes a very strong likelihood that we're missing something in the cosmological model that connects the two eras."

How the new study was done

Astronomers have been using Cepheid variables as cosmic yardsticks to gauge nearby intergalactic distances for more than a century. But trying to harvest a bunch of these stars was so time-consuming as to be nearly unachievable. So, the team employed a clever new method, called DASH (Drift And Shift), using Hubble as a "point-and-shoot" camera to snap quick images of the extremely bright pulsating stars, which eliminates the time-consuming need for precise pointing.


Image above: This illustration shows the three basic steps astronomers use to calculate how fast the universe expands over time, a value called the Hubble constant. All the steps involve building a strong "cosmic distance ladder," by starting with measuring accurate distances to nearby galaxies and then moving to galaxies farther and farther away. This "ladder" is a series of measurements of different kinds of astronomical objects with an intrinsic brightness that researchers can use to calculate distances. Among the most reliable for shorter distances are Cepheid variables, stars that pulsate at predictable rates that indicate their intrinsic brightness. Astronomers recently used the Hubble Space Telescope to observe 70 Cepheid variables in the nearby Large Magellanic Cloud to make the most precise distance measurement to that galaxy. Astronomers compare the measurements of nearby Cepheids to those in galaxies farther away that also include another cosmic yardstick, exploding stars called Type Ia supernovas. These supernovas are much brighter than Cepheid variables. Astronomers use them as "milepost markers" to gauge the distance from Earth to far-flung galaxies. Each of these markers build upon the previous step in the "ladder." By extending the ladder using different kinds of reliable milepost markers, astronomers can reach very large distances in the universe. Astronomers compare these distance values to measurements of an entire galaxy's light, which increasingly reddens with distance, due to the uniform expansion of space. Astronomers can then calculate how fast the cosmos is expanding: the Hubble constant. Image Credits: NASA, ESA and A. Feild (STScI).

"When Hubble uses precise pointing by locking onto guide stars, it can only observe one Cepheid per each 90-minute Hubble orbit around Earth. So, it would be very costly for the telescope to observe each Cepheid," explained team member Stefano Casertano, also of STScI and Johns Hopkins. "Instead, we searched for groups of Cepheids close enough to each other that we could move between them without recalibrating the telescope pointing. These Cepheids are so bright, we only need to observe them for two seconds. This technique is allowing us to observe a dozen Cepheids for the duration of one orbit. So, we stay on gyroscope control and keep 'DASHing' around very fast."

The Hubble astronomers then combined their result with another set of observations, made by the Araucaria Project, a collaboration between astronomers from institutions in Chile, the U.S., and Europe. This group made distance measurements to the Large Magellanic Cloud by observing the dimming of light as one star passes in front of its partner in eclipsing binary-star systems.

The combined measurements helped the SH0ES Team refine the Cepheids' true brightness. With this more accurate result, the team could then "tighten the bolts" of the rest of the distance ladder that extends deeper into space.

The new estimate of the Hubble constant is 74 kilometers (46 miles) per second per megaparsec. This means that for every 3.3 million light-years farther away a galaxy is from us, it appears to be moving 74 kilometers (46 miles) per second faster, as a result of the expansion of the universe. The number indicates that the universe is expanding at a 9% faster rate than the prediction of 67 kilometers (41.6 miles) per second per megaparsec, which comes from Planck's observations of the early universe, coupled with our present understanding of the universe.

So, what could explain this discrepancy?

One explanation for the mismatch involves an unexpected appearance of dark energy in the young universe, which is thought to now comprise 70% of the universe's contents. Proposed by astronomers at Johns Hopkins, the theory is dubbed "early dark energy," and suggests that the universe evolved like a three-act play.

Astronomers have already hypothesized that dark energy existed during the first seconds after the big bang and pushed matter throughout space, starting the initial expansion. Dark energy may also be the reason for the universe's accelerated expansion today. The new theory suggests that there was a third dark-energy episode not long after the big bang, which expanded the universe faster than astronomers had predicted. The existence of this "early dark energy" could account for the tension between the two Hubble constant values, Riess said.

Another idea is that the universe contains a new subatomic particle that travels close to the speed of light. Such speedy particles are collectively called "dark radiation" and include previously known particles like neutrinos, which are created in nuclear reactions and radioactive decays.

Yet another attractive possibility is that dark matter (an invisible form of matter not made up of protons, neutrons, and electrons) interacts more strongly with normal matter or radiation than previously assumed.

But the true explanation is still a mystery.

Riess doesn't have an answer to this vexing problem, but his team will continue to use Hubble to reduce the uncertainties in the Hubble constant. Their goal is to decrease the uncertainty to 1%, which should help astronomers identify the cause of the discrepancy.

The team's results have been accepted for publication in The Astrophysical Journal: https://iopscience.iop.org/journal/0004-637X

The Hubble Space Telescope is a project of international cooperation between NASA and ESA (European Space Agency). NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington, D.C.

Related article:

Latest Hubble Measurements Suggest Disparity in Hubble Constant Calculations is not a Fluke
https://orbiterchspacenews.blogspot.com/2019/04/latest-hubble-measurements-suggest.html

Related links:

Dark Energy and Dark Matter: http://www.nasa.gov/subject/6891/dark-energy-and-dark-matter/

Hubble Space Telescope: https://www.nasa.gov/mission_pages/hubble/main/index.html

Images (mentioned), Animation (mentioned), Text, Credits: NASA/Rob Garner/GSFC/Claire Andreoli/Space Telescope Science Institute/Donna Weaver/Ray Villard/Johns Hopkins University/Adam Riess.

Best regards, Orbiter.ch

Crew Juggles Emergency Drill, Space Biology and Dragon Preps











ISS - Expedition 59 Mission patch.

April 26, 2019

The six-member Expedition 59 crew conducted a routine, periodic drill for response to emergencies today in the middle of a science-packed day. The astronauts also researched space biology while preparing for next week’s SpaceX Dragon cargo mission.

The space residents practiced communications, roles and responsibilities, and evacuating the station in the unlikely event of an emergency. The crew would split up, board their Soyuz spacecraft and undock quickly for a ride back to Earth. The two Soyuz crew ships docked to the International Space Station each hold three crewmembers.


Image above: NASA astronaut Christina Koch works on the COLBERT treadmill inside the Tranquility module. Image Credit: NASA.

NASA Flight Engineers Nick Hague and Anne McClain set up the ultrasound and optometry instruments today for more Fluid Shifts studies. Flight surgeons are exploring what happens to an astronaut’s veins and eyes due to the head-ward flow of fluids caused by microgravity.

Hague later checked out command and communications gear he and astronaut David Saint-Jacques will use when the SpaceX Dragon resupply ship arrives next week. Saint-Jacques will command the Canadarm2 robotic arm to capture Dragon early Friday, May 2, two days after it launches from Florida. Hague will monitor Dragon’s telemetry during its approach and rendezvous. NASA TV is broadcasting the pre-flight activities and mission events live.

International Space Station (ISS). Image Credit: NASA

Saint-Jacques and Flight Engineer Christina Koch also split the day feeding mice and cleaning cages for the Rodent Research-12 experiment. The study is investigating the immune system’s response to the conditions of long-term spaceflight.

Commander Oleg Kononenko focused much of his attention today on life support maintenance in the Russian segment of the orbital lab. Flight Engineer Alexey Ovchinin studied ways to maximize the effectiveness of exercise in the weightless environment of microgravity.

Related links:

Expedition 59: https://www.nasa.gov/mission_pages/station/expeditions/expedition59/index.html

SpaceX Dragon: https://www.nasa.gov/spacex

Canadarm2 robotic arm: https://www.nasa.gov/mission_pages/station/structure/elements/mobile-servicing-system.html

NASA TV: https://www.nasa.gov/nasatv

Rodent Research-12: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7868

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Text, Credits: NASA/Mark Garcia.

Best regards, Orbiter.ch

Hubble Snaps a Crowded Cluster












NASA - Hubble Space Telescope (HST) patch.

April 26, 2019


This sparkling burst of stars is Messier 75. It is a globular cluster: a spherical collection of stars bound together by gravity. Clusters like this orbit around galaxies and typically reside in their outer and less-crowded areas, gathering to form dense communities in the galactic suburbs.

Messier 75 lies in our Milky Way galaxy in the constellation of Sagittarius (the Archer), around 67,000 light-years away from Earth. The majority of the cluster’s stars, about 400,000 in total, are found in its core; it is one of the most densely populated clusters ever found, with a phenomenal luminosity of some 180,000 times that of the Sun. No wonder it photographs so well!

Discovered in 1780 by Pierre Méchain, Messier 75 was also observed by Charles Messier and added to his catalog later that year. This image of Messier 75 was captured by the NASA/ESA Hubble Space Telescope’s Advanced Camera for Surveys.

Messier 75 is featured in Hubble’s Messier catalog, which includes some of the most fascinating objects that can be observed from Earth’s Northern Hemisphere. See the NASA-processed image and other Messier objects at: https://www.nasa.gov/content/goddard/hubble-s-messier-catalog.

Hubble Space Telescope (HST)

For more information about Hubble, visit:

http://hubblesite.org/

http://www.nasa.gov/hubble

http://www.spacetelescope.org/

Text Credits: ESA (European Space Agency)/NASA/Rob Garner/Image, Animation, Credits: ESA/Hubble & NASA, F. Ferraro et al.

Greetings, Orbiter.ch

Successful Operation of Asteroid Explorer Hayabusa2's SCI












JAXA - Hayabusa2 Mission patch.

April 26, 2019

Japan Aerospace Exploration Agency (JAXA) separated the SCI (Small Carry-on Impactor), which had been onboard the asteroid explorer Hayabusa2, on April 5, 2019, for deployment to Ryugu, and then put the SCI into operation.

As a result of checking the images captured by the Optical Navigation Camera - Telescopic (ONC-T) onboard the asteroid explorer Hayabusa2, we have concluded that a crater was created by the SCI.

Hayabusa2 is operating normally.


Images above: Images taken by the ONC-T; Left image: Taken on March 22, 2019; Right image: Taken on April 25, 2019; (Onboard date, JST).

These images were captured by the Optical Navigation Camera - Telescopic onboard Hayabusa2. By comparing the two images, we have confirmed that an artificial crater was created in the area surrounded by dotted lines. The size and depth of the crater are now under analysis.

Image credit: JAXA, The University of Tokyo, Kochi University, Rikkyo University, Nagoya University, Chiba Institute of Technology, Meiji University, The University of Aizu, AIST.

Related article:

Asteroid Explorer Hayabusa2’s Science - Put into Operation
https://orbiterchspacenews.blogspot.com/2019/04/asteroid-explorer-hayabusa2s-science.html

Related links:

Hayabusa2 Asteroid Probe (ISAS): http://www.isas.jaxa.jp/en/missions/spacecraft/current/hayabusa2.html

Asteroid Explorer "Hayabusa2": http://global.jaxa.jp/projects/sas/hayabusa2/index.html

Images (mentioned), Text, Credits: Japan Aerospace Exploration Agency (JAXA)/National Research and Development Agency.

Best regards, Orbiter.ch

Antarctica's Effect on Sea Level Rise in Coming Centuries













JPL - Jet Propulsion Laboratory logo.

April 26, 2019

There are two primary causes of global mean sea level rise - added water from melting ice sheets and glaciers, and the expansion of sea water as it warms. The melting of Antarctica's ice sheet is currently responsible for 20-25% of global sea level rise.

But how much of a role will it play hundreds of years in the future?

Scientists rely on precise numerical models to answer questions like this one. As the models used in predicting long-term sea level rise improve, so too do the projections derived from them. Scientists at NASA's Jet Propulsion Laboratory in Pasadena, California, have discovered a way to make current models more accurate. In doing so, they have also gotten one step closer to understanding what Antarctica's ice sheet - and the sea level rise that occurs as it melts - will look like centuries from now.

Thwaites Glacier. Image Credits: NASA/James Yungel

"Unlike most current models, we included solid Earth processes - such as the elastic rebound of the bedrock under the ice, and the impact of changes in sea level very close to the ice sheet," said JPL's Eric Larour, first author of the study. "We also examined these models at a much higher resolution than is typically used - we zoomed in on areas of bedrock that were about 1 kilometer instead of the usual 20 kilometers."

The scientists found that projections for the next 100 years are within 1% of previous projections for that time period; however, further into the future, they observed some significant differences.

"We found that around the year 2250, some of these solid Earth processes started to offset the melting of the ice sheet and the consequent sea level rise," Larour said. In other words, they actually slowed the melting down.

The team noted that a hundred years even further into the future - by 2350 - this slowdown means that the melting of the ice sheet is likely to contribute 29% less to global sea level rise than previous models indicated.


Animation above: This animation shows projections of ice sheet retreat in Antarctica over 500 years using the previous models (shown in green) and the new models, which take into account solid Earth processes like the elastic rebound of the Earth (shown in red). The new models show that by the year 2350, melting of the ice sheet and its corresponding contribution to sea-level rise will be about 29% less than what previous projections had indicated for this distant time period. Animation Credits: NASA/JPL-Caltech.

"One of the main things we learned was that as grounded ice retreats inland, the bedrock under it lifts up elastically," said Erik Ivins, a co-author of the study. "It's similar to how a sofa cushion decompresses when you remove your weight from it. This process slows down the retreat of the ice sheet and ultimately the amount of melting."

Although this sounds like good news, the scientists say it's important to keep it in perspective. "It's like a truck traveling downhill that encounters speed bumps in the road," said Larour. "The truck will slow down a bit but will ultimately continue down the hill" - just as the ice sheet will continue to melt and sea level will continue to rise.

The breakthrough of this study, he added, was to "reach resolutions high enough to capture as many of these 'speed bumps' as possible and determine their effects in Antarctica while also modeling sea level rise over the entire planet."

The study, titled "Slowdown in Antarctic Mass Loss from Solid Earth and Sea-Level Feedback," was published today in Science.

More information on the study can be found at: https://vesl.jpl.nasa.gov/sea-level/slr-uplift

Image (mentioned), Animation (mentioned), Text, Credits: NASA/JPL/Esprit Smith.

Greetings, Orbiter.ch

The Giant Galaxy Around the Giant Black Hole













NASA - Spitzer Space Telescope patch.

April 26, 2019

On April 10, 2019, the Event Horizon Telescope (EHT) unveiled the first-ever image of a black hole's event horizon, the area beyond which light cannot escape the immense gravity of the black hole. That giant black hole, with a mass of 6.5 billion Suns, is located in the elliptical galaxy Messier 87 (M87). EHT is an international collaboration whose support in the U.S. includes the National Science Foundation.

This image from NASA's Spitzer Space Telescope shows the entire M87 galaxy in infrared light. The EHT image, by contrast, relied on light in radio wavelengths and showed the black hole's shadow against the backdrop of high-energy material around it.

Spitzer Captures Messier 87

Image above: The galaxy M87, imaged here by NASA's Spitzer Space Telescope, is home to a supermassive black hole that spews two jets of material out into space at nearly the speed of light. The inset shows a close-up view of the shockwaves created by the two jets. Image Credits: NASA/JPL-Caltech/IPAC.

Located about 55 million light-years from Earth, M87 has been a subject of astronomical study for more than 100 years and has been imaged by many NASA observatories, including the Hubble Space Telescope, the Chandra X-ray Observatory and NuSTAR. In 1918, astronomer Heber Curtis first noticed "a curious straight ray" extending from the galaxy's center. This bright jet of high-energy material, produced by a disk of material spinning rapidly around the black hole, is visible in multiple wavelengths of light, from radio waves through X-rays. When the particles in the jet impact the interstellar medium (the sparse material filling the space between stars in M87), they create a shockwave that radiates in infrared and radio wavelengths of light but not visible light. In the Spitzer image, the shockwave is more prominent than the jet itself.

The brighter jet, located to the right of the galaxy's center, is traveling almost directly toward Earth. Its brightness is amplified due to its high speed in our direction, but even more so because of what scientists call "relativistic effects," which arise because the material in the jet is traveling near the speed of light. The jet's trajectory is just slightly offset from our line of sight with respect to the galaxy, so we can still see some of the length of the jet. The shockwave begins around the point where the jet appears to curve down, highlighting the regions where the fast-moving particles are colliding with gas in the galaxy and slowing down.


Image above: The galaxy M87 looks like a hazy, blue space-puff in this image from NASA's Spitzer Space Telescope. At the galaxy's center is a supermassive black hole that spews two jets of material out into space. Image Credits: NASA/JPL-Caltech/IPAC.

The second jet, by contrast, is moving so rapidly away from us that the relativistic effects render it invisible at all wavelengths. But the shockwave it creates in the interstellar medium can still be seen here.

Located on the left side of the galaxy's center, the shockwave looks like an inverted letter "C." While not visible in optical images, the lobe can also be seen in radio waves, as in this image from the National Radio Astronomy Observatory's Very Large Array.

By combining observations in the infrared, radio waves, visible light, X-rays and extremely energetic gamma rays, scientists can study the physics of these powerful jets. Scientists are still striving for a solid theoretical understanding of how gas being pulled into black holes creates outflowing jets.


Image above: This wide-field image of the galaxy M87 was taken by NASA's Spitzer Space Telescope. The top inset shows a close-up of two shockwaves, created by a jet emanating from the galaxy's supermassive black hole. The Event Horizon Telescope recently took a close-up image of the silhouette of that black hole, show in the second inset. Image Credits: NASA/JPL-Caltech/Event Horizon Telescope Collaboration.

Infrared light at wavelengths of 3.6 and 4.5 microns are rendered in blue and green, showing the distribution of stars, while dust features that glow brightly at 8.0 microns are shown in red. The image was taken during Spitzer's initial "cold" mission.

Animation Credit: NASA

The Jet Propulsion Laboratory in Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at Caltech in Pasadena. Space operations are based at Lockheed Martin Space Systems in Littleton, Colorado. Data are archived at the Infrared Science Archive housed at IPAC at Caltech. Caltech manages JPL for NASA.

Related article:

Astronomers Capture First Image of a Black Hole
https://orbiterchspacenews.blogspot.com/2019/04/astronomers-capture-first-image-of.html

Related links:

National Science Foundation: http://www.nsf.gov/blackholes

Hubble Space Telescope: https://www.nasa.gov/feature/goddard/2017/messier-87

Chandra X-ray Observatory: http://chandra.si.edu/photo/2019/black_hole/

NuSTAR: https://www.nasa.gov/mission_pages/nustar/main/index.html

Event Horizon Telescope (EHT): https://www.jpl.nasa.gov/news/news.php?feature=7372

More information on Spitzer can be found at its website: http://www.spitzer.caltech.edu/

Images (mentioned), Animation (mentioned), Text, Credits: NASA/JPL/Calla Cofield.

Best regards, Orbiter.ch

The day the asteroid might hit












Asteroid Watch logo.

26 April 2019

For the first time, ESA will cover a major international asteroid impact exercise live via social media, highlighting the the actions that might be taken by scientists, space agencies and civil protection organisations.

Visualisation of asteroid Itokawa

Every two years, asteroid experts from across the globe come together to simulate a fictional but plausible imminent asteroid impact on Earth. During the week-long scenario, participants – playing roles such as ‘national government’, ‘space agency’, ‘astronomer’ and ‘civil protection office’ – don't know how the situation will evolve from one day to the next, and must make plans based on the daily updates they are given.

For the first time, ESA will cover progress of the hypothetical impact scenario from 29 April to 3 May live via social media, primarily via the @esaoperations Twitter channel.

Planetary Defence Conference

The exercise is being produced by experts from NASA’s Planetary Defense Coordination Office working together with the US Federal Emergency Management Agency at the 2019 Planetary Defense Conference, Washington DC. The conference is the world’s most important gathering of asteroid experts, and is strongly supported by ESA, NASA and other agencies, organisations and scientific institutions.

“The first step in protecting our planet is knowing what’s out there,” says Rüdiger Jehn, ESA’s Head of Planetary Defence.

ESA's Flyeye telescope is now being built in Italy

“Only then, with enough warning, can we take the steps needed to prevent an asteroid strike altogether, or to minimise the damage it does on the ground.”

20'000 asteroid milestone

As of April 2019, 20 000 asteroids whose orbit brings them near Earth have been found. At the current rate of roughly 150 new discoveries every month, this number is set to rapidly increase.

With the planned deployments of ESA’s new Flyeye and Test-Bed Telescopes, Europe’s ability to discover, confirm and understand the ancient rocks that hurtle through space will grow – fundamental to implementing mitigation measures.

Follow asteroid impact exercise live

The @esaoperations Twitter channel will share updates on the asteroid impact exercise in realtime, including daily press releases revealing how the asteroid impact scenario will evolve, so followers will find out the ‘news’ as the experts do.

What will they do? What would you do?

On ESA Facebook, join us for two live-stream videos straight from the Planetary Defense Conference. The first will be on Sunday, 28 April, at 14:00 CEST (08:00 EDT) with Rüdiger Jehn, ESA’s Head of Planetary Defence, and the second on Thursday, 2 May, at around mid-afternoon European time.

Estimated risk corridor for the impact of a hypothetical asteroid

For daily updates on the asteroid impact scenario, check out “Rolling coverage: Brace for hypothetical asteroid impact”, beginning on the first day of the conference, Monday, 29 April, over on ESA's Rocket Science blog.

Hypothetical impact

Follow ESA's first-ever live coverage of a hypothetical asteroid impact exercise from the international Planetary Defense Conference
http://blogs.esa.int/rocketscience/2019/04/25/rolling-coverage-brace-for-hypothetical-asteroid-impact/

Asteroid 2019 PDC hypothetical impact scenario

The scene has been set for this year’s hypothetical impact scenario. Although realistic, it is completely fictional and does not describe an actual asteroid impact.

- An asteroid was discovered on 26 March 2019 and was given the name '2019 PDC' by the Minor Planet Center.

- Very little is known about this newly discovered asteroid’s physical properties. With a magnitude (brightness) of 21.1 – invisible to the naked eye but viewable by professional astronomers – it has been classed as a ‘Potentially Hazardous Asteroid’, and experts have determined its average size could be anywhere from 100-300 metres.

- The day after 2019 PDC was discovered, ESA and NASA’s ‘impact monitoring systems’ identified several future dates when the asteroid could hit Earth. At this early stage, with not many observations yet recorded, both systems agreed that the asteroid was most likely to strike on 29 April 2027 – more than eight years away – with a probability of impact of about 1 in 50 000.

- Astronomers continued to monitor the asteroid for a month after its initial detection, which provided them more information about the object’s trajectory, and have now discovered that the chance of impact is rapidly increasing. By 29 April 2019, (the first day of the Planetary Defence Conference), the probability of impact has risen to 1 in 100.

ESA coordinates European efforts

The 2019 Planetary Defence Conference will be the sixth such conference that the International Academy of Astronautics (IAA) has held; and ESA has been closely involved with all of them.

ESA's planned Hera mission will test asteroid deflection techniques

As in previous years, ESA is sponsoring the event and providing a conference co-chair. A large team of ESA experts will also be present, including members of the Agency’s Near-Earth Object Coordination Centre and the Hera asteroid deflection mission.

During the hypothetical asteroid impact scenario, ESA experts will participate in discussions on the possible risks posed by asteroid 2019 PDC, and what responses could be considered.

“Fortunately, impacts from medium and large asteroids are not very common,” explains Detlef Koschny, senior asteroid expert at ESA who will be involved in the hypothetical scenario.”

“However, this means we have little opportunity to practise our response to this very real – though unlikely – danger. This year’s impact scenario is a very unique chance to run through, in real-time, an asteroid impact.”

Space Safety at ESA

Solar activity, asteroids and artificial space debris all pose threats to our planet and our use of space.

Space Safety & Security at ESA

ESA's Space Safety activities aim to safeguard society and the critical satellites on which we depend, identifying and mitigating threats from space through projects such as the Flyeye telescopes, the Lagrange space weather mission and the Hera asteroid mission.

As asteroid experts meet for the international Planetary Defense Conference, ESA is focusing on the threat we face from space rocks. How likely is an asteroid impact? What is ESA doing to mitigate impact risks? Follow the hashtag #PlanetaryDefense to find out more.

Related article:

NASA, FEMA, International Partners Plan Asteroid Impact Exercise
https://orbiterchspacenews.blogspot.com/2019/04/nasa-fema-international-partners-plan.html
 
Related links:

@esaoperations Twitter channel: http://www.twitter.com/esaoperations

ESA Facebook: http://www.facebook.com/europeanspaceagency

NASA’s Planetary Defense Coordination Office: https://www.nasa.gov/feature/nasa-fema-international-partners-plan-asteroid-impact-exercise

2019 Planetary Defense Conference: http://pdc.iaaweb.org/

ESA's Rocket Science blog: http://blogs.esa.int/rocketscience

Near-Earth Object Coordination Centre: http://neo.ssa.esa.int/

Hera asteroid deflection mission: http://www.esa.int/Our_Activities/Operations/Space_Safety_Security/Hera

#PlanetaryDefense: https://twitter.com/search?l=&q=%23PlanetaryDefense&src=typd

Images, Video, Text, Credits: European Space Agency (ESA)/A. Baker, CC BY-SA 3.0 IGO/ScienceOffice.org.

Greetings, Orbiter.ch

jeudi 25 avril 2019

Hermes to Bring Asteroid Research to the ISS













ISS - International Space Station logo.

April 25, 2019

Asteroid researchers on Earth will soon gain a powerful new way to remotely conduct experiments aboard the International Space Station. The device, called the Hermes Facility, is an experiment station that can communicate with scientists on the ground and give them the ability to control their studies almost as if they were in space themselves. Hermes will be carried to the space station aboard the SpaceX CRS-17 ferry flight.

International Space Station (ISS). Animation Credit: NASA

Hermes is the creation of Dr. Kristen John, a researcher with the Astromaterials Research and Exploration Science (ARES) division at NASA’s Johnson Space Center (JSC). John and her research team developed Hermes as a way to study how samples of simulated asteroid particles behave in microgravity and the vacuum of space.

Researching Regolith

The material John is studying with Hermes is called asteroid regolith. The term is used for the layer of dusty, fragmented debris covering asteroids and moons created by impacts from meteorites and other forces on their surfaces.


Image above: Hermes Principal Investigator, Kristen John, stands in front of the Hermes hardware. On the right is the Hermes Facility, and on the the left is Cassette-1, the first set of science experiments to be installed in the Facility. Image Credit: NASA.

“We need to study this material to understand how it’s going to affect our spacecraft that interact with the surface of asteroids, or the joints of spacesuits worn by astronauts one day exploring them,” John said.

Studying regolith also helps scientists understand the underpinning of how asteroids, moons and planets, such as our Earth, developed.

Messages from Space

John and her team designed Hermes to connect to the station’s existing systems – including communications – so that it could be completely monitored and controlled from the ground. Hermes is also made to be easily adapted to many types of experiments.

“We named it for the Greek messenger god, Hermes, because we’ve designed a system that can deliver research data and experiments back forth between space and scientists,” John said.


Image above: The Cassette-1 hardware sits in a lab at Johnson Space Center. The Cassette includes the four experiments, electronics to control the experiments, and a vacuum system on the underside consisting of transducers, pipes, hoses, and valves. Image Credit: NASA.

Hermes is roughly the size of a large desktop computer and the experiments themselves are housed inside a removable carrier, called a cassette, which slides into Hermes.

John was assisted in designing and building Hermes by a team consisting of JSC, the University of Central Florida and researchers and students affiliated with Texas A&M University through a partnership with Texas Space, Technology, Applications and Research.

The JSC team included Kenton Fisher, an ARES engineer who led the development of Hermes’ vacuum system, and project manager Veronica Saucedo with the Project Management and Integration Office of the Engineering Directorate.

“There is no greater satisfaction than seeing this project through from concept to delivery,” Saucedo said. “I’m excited to see how the capability of this game-changing facility impacts asteroid, planetary science and exploration research.”

The Experiment

The space station crew will install Hermes into an EXPRESS rack aboard the lab.

“After that, the crew will flip a few switches, and we’ll basically take over from there,” John said.


Image above: The Hermes Facility headed to the International Space Station supports material investigations with applications to asteroids, planetary science, and exploration. Image Credits: NASA/Johnson Space Center.

John’s experiments for Cassette-1 are housed inside four clear, 10-inch plastic tubes containing materials meant to simulate regolith. Three of the tubes hold different-sized particles of silica glass. The fourth tube has a meteorite simulant which is a blend of variously sized particles, formulated especially for the experiment by Professor Addie Dove and students from the University of Central Florida.

“This experiment gave our students a chance to work on hardware that will actually fly on the ISS,” Dove said. “They had to understand the experiment design and fabrication cycle, how to meet specifications and produce a quality product. This is much different than what they have to do in classes and provides valuable experience.”

Over the coming months, John and her team will be watching to see how the regolith particles behave in response to long duration exposure to microgravity, and to changes in pressure, temperature, shocks from impacts and other forces. Once the regolith experiments inside Cassette-1 are complete, it will be removed from Hermes, returned to Earth and replaced with a new cassette of different experiments.

Related article:

Dragon’s 17th Flight Carries Science to the Space Station
https://orbiterchspacenews.blogspot.com/2019/04/dragons-17th-flight-carries-science-to.html

Related links:

Hermes Facility: https://www.nasa.gov/mission_pages/station/research/experiments/2603.html

Astromaterials Research and Exploration Science (ARES): https://ares.jsc.nasa.gov/

Asteroids: https://www.nasa.gov/mission_pages/asteroids/main/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Animation (mentioned), Text, Credits: NASA/Noah Michelsohn/JSC/International Space Station Program Science Office/Charlie Plain.

Greetings, Orbiter.ch

Biomedical and Botany Research Today as Station Preps for Sixth Spacecraft











ISS - Expedition 59 Mission patch.

April 25, 2019

Vein scans and eye checks were on the schedule today as the Expedition 59 crew continues ongoing biomedical studies. The International Space Station is also getting ready to host a sixth spacecraft when it arrives next week.

Scientists have been observing the space residents all week as they seek to understand the effects of the upward flow of body fluids in space. Flight Engineer Anne McClain worked on the Fluid Shifts experiment again today attaching body electrodes to NASA astronaut Nick Hague and conducting ultrasound scans of his veins. She also peered into his eyes using optical tomography coherence hardware. Results may help flight surgeons prevent the increased head and eye pressure caused by the upward fluid shifts astronauts report in space.


Image above: The aurora australis, also known as the “southern lights”, is pictured as the International Space Station orbited 265 miles above the Indian Ocean southwest of Australia. Image Credit: NASA.

NASA is also learning how to support longer human missions farther out into space. Feeding crews without expensive cargo missions and fuel-consuming inventories is critical. As a result, the station provides a variety of greenhouse facilities for plant cultivation and research. Christina Koch of NASA set up new botany hardware today to enable the ongoing research and harvesting of lettuce and mizuna in space.

Station Crew Views the Frozen Southern Tip of Hudson Bay

Image above: On April, 22, 2019, the crew aboard the International Space Station snapped this image of the Hudson Bay's frozen southern tip, which lies in between Ontario and Quebec, as the Space Station orbited 258 miles above Canada. Image Credit: NASA.

The SpaceX Dragon resupply ship is due to liftoff Tuesday at 4:21 a.m. EDT on its 17th contracted cargo mission to the station. Canadian Space Agency astronaut David Saint-Jacques is training to capture Dragon with the Canadarm2 robotic arm when it arrives Thursday May 2 at 6:50 a.m. A pair of new experiments it is delivering will explore atmospheric carbon dioxide as well as X-ray frequency communication techniques.

NASA to Broadcast Next Space Station Resupply Launch, Prelaunch Activities

Launch time has been updated to 4:21 a.m. EDT and spacecraft capture now is set for 6:50 a.m. NASA TV coverage off capture will begin at 5 a.m. (Updated April 25, 2019)

NASA commercial cargo provider SpaceX is targeting no earlier than 4:21 a.m. EDT Tuesday, April 30, for the launch of its next resupply mission to the International Space Station. Live coverage will begin on NASA Television and the agency’s website Monday, April 29, with prelaunch events. 

This is the 17th SpaceX mission under NASA’s Commercial Resupply Services contract. The Dragon spacecraft will deliver supplies and critical materials to support dozens of the more than 250 science and research investigations that will occur during Expeditions 59 and 60. The spacecraft’sunpressurized trunk will transport NASA’s Orbiting Carbon Observatory-3 (OCO-3) and Space Test Program-Houston 6 (STP-H6).


Image above: A two-stage SpaceX Falcon 9 launch vehicle lifts off from Space Launch Complex 40 at Cape Canaveral Air Force Station in Florida on December 5, 2018 at 1:16 p.m. EST, carrying the 16th Commercial Resupply Services mission to the International Space Station. Image Credit: NASA.

OCO-3 will be installed robotically on the exterior of the space station’s Japanese Experiment Module Exposed Facility Unit, where it will measure and map carbon dioxide from space to increase our understanding of the relationship between carbon and climate. STP-H6 is an X-ray communication investigation that will be used to perform a space-based demonstration of a new technology for generating beams of modulated X-rays. This technology may be useful for providing efficient communication to deep space probes, or communicating with hypersonic vehicles where plasma sheaths prevent traditional radio communications.

The spacecraft will take two days to reach the space station before installation on Thursday, May 2. When it arrives, astronaut David Saint-Jacques of the Canadian Space Agency will grapple Dragon, with NASA astronaut Nick Hague serving as backup. NASA astronaut Christina Koch will assist by monitoring telemetry during Dragon’s approach. After Dragon capture, mission control in Houston will send commands to the station’s arm to rotate and install the spacecraft on the bottom of the station’s Harmony module.

Related article:

Dragon’s 17th Flight Carries Science to the Space Station
https://orbiterchspacenews.blogspot.com/2019/04/dragons-17th-flight-carries-science-to.html

Related links:

NASA Television: https://www.nasa.gov/live

Expedition 59: https://www.nasa.gov/mission_pages/station/expeditions/expedition59/index.html

Fluid Shifts: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1126

Lettuce and mizuna: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7581

Atmospheric carbon dioxide: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1786

X-ray frequency communication: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7947

Orbiting Carbon Observatory-3 (OCO-3): https://ocov3.jpl.nasa.gov/

Space Test Program-Houston 6 (STP-H6): https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7947

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Images (mentioned), Text, Credits: NASA/Mark Garcia/Sean Potter/Josh Finch/Kennedy Space Center/Mary MacLaughlin.

Best regards, Orbiter.ch

Next-Generation NASA Instrument Advanced to Study the Atmospheres of Uranus and Neptune











NASA - Galileo Mission patch.

April 25, 2019

Much has changed technologically since NASA’s Galileo mission dropped a probe into Jupiter’s atmosphere to investigate, among other things, the heat engine driving the gas giant’s atmospheric circulation.

A NASA scientist and his team at the Goddard Space Flight Center in Greenbelt, Maryland, are taking advantage of those advances to mature a smaller, more capable net flux radiometer. This type of instrument tells scientists where heating and cooling occurs in a planet’s atmosphere and defines the roles of solar and internal heat sources that contribute to atmospheric motions. The next-generation radiometer is specifically being developed to study the atmospheres of Uranus or Neptune, but could be used on any target with an atmosphere.


Image above: NASA’s Voyager 2 spacecraft gave humanity its first glimpse of Neptune and its moon, Triton, in the summer of 1989. This image, taken at a range of 4.4 million miles from the planet, shows the Great Dark Spot and its companion bright smudge. These clouds were seen to persist for as long as Voyager’s cameras could resolve them. Image Credit: NASA.

Of all the planets in the solar system, only Uranus and Neptune — called the ice giants because they are composed mostly of ices — remain relatively unexplored. While Voyager 2 snapped photos of the seventh and eighth planets, it did not obtain the breathtaking details that the Galileo and Cassini missions gathered about Jupiter and Saturn. Even far-flung Pluto scored a close-up look with the New Horizons mission in 2015.

A lot remains to be discovered, said Shahid Aslam, who is leading the team developing the next-generation instrument, an effort funded by NASA’s Planetary Concepts for the Advancement of Solar System Observations, or PICASSO, program.

Scientists do know that both Uranus and Neptune host a slushy mantle of water, ammonia, and methane ices, while their atmospheres consist of molecular hydrogen, helium, and methane gas. However, differences exist in these cold outer Jovian worlds.

As temperatures fall below -333.7 degrees Fahrenheit, ammonia gas freezes into ice crystals and drops out of the atmospheres of both planets. Methane — a blue-colored gas — becomes dominant. While atmospheric-methane content is similar in both planets, they look different. Uranus appears as a hazy blue-green, while Neptune takes on a much deeper color blue. Some unknown atmospheric constituent is thought to contribute to Neptune’s deeper blue color, Aslam said.


Image above: This is an image of the planet Uranus taken by the spacecraft Voyager 2, which flew closely past the seventh planet from the Sun in January 1986. Image Credit: NASA.

Also, Uranus lacks internal heat. Consequently, its clouds are cold and don’t billow above the top haze layer. Neptune, on the other hand, radiates as much energy as it receives from the Sun. This internal energy gives Neptune an active, dynamic atmosphere, distinguished by dark belts and bright clouds of methane ice and cyclonic storms.

Because NASA has never flown a dedicated mission to the ice giants, details of the physics driving these atmospheric conditions remain elusive, Aslam said.

He believes the new instrument could provide answers.

It’s a successor to a similar type instrument that gathered data about Jupiter’s atmospheric conditions before being crushed by Jupiter’s atmospheric pressure in December 1995. During that perilous, 58-minute ride deep into the planet’s atmosphere, Galileo’s net flux radiometer — one of several mounted inside the probe — measured radiation that reached the planet from the Sun above as well as the thermal radiation or heat generated by the planet itself below. These top and bottom measurements helped scientists calculate the difference between the two — a measurement called net flux.

In addition to providing details about atmospheric heating and cooling, net flux data reveal information about cloud layers and their chemical composition. “Actually, you can learn a lot from net flux data, especially sources and sinks of planetary radiation,” Aslam said.

Like its predecessor, Aslam’s instrument would take a suicidal plunge through the atmospheres of either Uranus or Neptune. But as it made its descent, it would gather information about these poorly understood regions with greater accuracy and efficiency, Aslam said. “Available materials, filters, electronic detectors, flight computing, and data management and processing have all improved. Frankly, we have better technology all the way around. It’s clear that the time is now to develop the next generation of this instrument for future atmospheric entry probes,” he said.

NASA’s Galileo probe at Jupiter flyby. Image Credit: NASA

Instead of using pyroelectric detectors employed on Galileo, for example, Aslam is eyeing the use of thermopile sensors, which convert heat or infrared wavelengths or heat into electrical signals. The advantage is that thermopile circuitry is less susceptible to disturbances and electrical noise.

Aslam’s team is also adding two additional infrared channels to measure heat, bringing the total to seven, and two additional viewing angles with which to gather these wavelengths and help model light scattering. When light scatters in one field of view due to interactions with aerosols and ice particles, the scattering can contaminate measurements in another field of view. This gives scientists a skewed picture of what’s happening when they analyze the data.

Furthermore, the instrument’s tighter field of view will reveal greater detail about the planet’s cloud decks and atmospheric layers as the instrument makes it descent. Just as important, the instrument is smaller and its sensors employ modern application-specific integrated circuits that support fast data sampling, Aslam said.

Related articles & links:

Hubble Reveals Dynamic Atmospheres of Uranus, Neptune
https://orbiterchspacenews.blogspot.com/2019/02/hubble-reveals-dynamic-atmospheres-of.html

NASA Completes Study of Future ‘Ice Giant’ Mission Concepts
https://orbiterchspacenews.blogspot.com/2017/06/nasa-completes-study-of-future-ice.html

For more Goddard technology news, go to:
https://www.nasa.gov/sites/default/files/atoms/files/spring_2019_final_web_version.pdf

NASA’s Galileo mission: https://www.jpl.nasa.gov/missions/galileo/

Neptune: https://www.nasa.gov/subject/3157/neptune

Uranus: http://www.nasa.gov/uranus

Space Tech: https://www.nasa.gov/topics/technology/index.html

Images (mentioned), Text, Credits: NASA/Lynn Jenner/Goddard Space Flight Center, by ​Lori Keesey.

Greetings, Orbiter.ch

Latest Hubble Measurements Suggest Disparity in Hubble Constant Calculations is not a Fluke













ESA - Hubble Space Telescope logo.

25 April 2019

LHA 120-N11 in the Large Magellanic Cloud

Hubble’s measurements of today’s expansion rate do not match the rate that was expected based on how the Universe appeared shortly after the Big Bang over 13 billion years ago. Using new data from the NASA/ESA Hubble Space Telescope, astronomers have significantly lowered the possibility that this discrepancy is a fluke.

Using new observations from the NASA/ESA Hubble Space Telescope, researchers have improved the foundations of the cosmic distance ladder, which is used to calculate accurate distances to nearby galaxies. This was done by observing pulsating stars called Cepheid variables in a neighbouring satellite galaxy known as the Large Magellanic Cloud, now calculated to be 162,000 light-years away. When defining the distances to galaxies that are further and further away, these Cepheid variables are used as milepost markers. Researchers use these measurements to determine how fast the Universe is expanding over time, a value known as the Hubble constant.

The entire Large Magellanic Cloud with annotations (ground-based image)

Before Hubble was launched in 1990, estimates of the Hubble constant varied by a factor of two. In the late 1990s the Hubble Space Telescope Key Project on the Extragalactic Distance Scale refined the value of the Hubble constant to within 10 percent, accomplishing one of the telescope’s key goals. In 2016, astronomers using Hubble discovered that the Universe is expanding between five and nine percent faster than previously calculated by refining the measurement of the Hubble constant and further reducing the uncertainty to only 2.4 percent. In 2017, an independent measurement supported these results. This latest research has reduced the uncertainty in their Hubble constant value to an unprecedented 1.9 percent.

This research also suggests that the likelihood that this discrepancy between measurements of today’s expansion rate of the Universe and the expected value based on the early Universe’s expansion is a fluke is just 1 in 100,000, a significant improvement from a previous estimate last year of 1 in 3,000.

“The Hubble tension between the early and late Universe may be the most exciting development in cosmology in decades,” said lead researcher and Nobel Laureate Adam Riess of the Space Telescope Science Institute (STScI) and Johns Hopkins University, in Baltimore, USA. “This mismatch has been growing and has now reached a point that is really impossible to dismiss as a fluke. This disparity could not plausibly occur by chance.”

Animation of cosmic distance ladder

As the team’s measurements have become more precise, their calculation of the Hubble constant has remained inconsistent with the expected value derived from observations of the early Universe’s expansion made by the European Space Agency’s Planck satellite. These measurements map a remnant afterglow from the Big Bang known as the Cosmic Microwave Background, which help scientists to predict how the early Universe would likely have evolved into the expansion rate astronomers can measure today.

The new estimate of the Hubble constant is 74.03 kilometres per second per megaparsec [1]. The number indicates that the Universe is expanding at a rate about 9 percent faster than that implied by Planck’s observations of the early Universe, which give a value for the Hubble constant of 67.4 kilometres per second per megaparsec.

To reach this conclusion, Riess and his team analysed the light from 70 Cepheid variables in the Large Magellanic Cloud. Because these stars brighten and dim at predictable rates, and the periods of these variations give us their luminosity and hence distance, astronomers use them as cosmic mileposts. Riess’s team used an efficient observing technique called Drift And Shift (DASH) using Hubble as a “point-and-shoot” camera to snap quick images of the bright stars. This avoids the more time-consuming step of anchoring the telescope with guide stars to observe each star. The results were combined with observations made by the Araucaria Project, a collaboration between astronomers from institutions in Europe, Chile, and the United States, to measure the distance to the Large Magellanic Cloud by observing the dimming of light as one star passes in front of its partner in a binary-star system.

Hubble Space Telescope (HST)

Because cosmological models suggest that observed values of the expansion of the Universe should be the same as those determined from the Cosmic Microwave Background, new physics may be needed to explain the disparity. “Previously, theorists would say to me, ‘it can’t be. It’s going to break everything.’ Now they are saying, ‘we actually could do this,’” Riess said.

Various scenarios have been proposed to explain the discrepancy, but there is yet to be a conclusive answer. An invisible form of matter called dark matter may interact more strongly with normal matter than astronomers previously thought. Or perhaps dark energy, an unknown form of energy that pervades space, is responsible for accelerating the expansion of the Universe.

Although Riess does not have an answer to this perplexing disparity, he and his team intend to continue using Hubble to reduce the uncertainty in their measure of the Hubble constant, which they hope to decrease to 1 percent.

The team’s results have been accepted for publication in The Astrophysical Journal: https://iopscience.iop.org/journal/0004-637X

Notes:

[1] This means that for every 3.3 million light-years further away a galaxy is from us, it appears to be moving about 74 kilometres per second faster, as a result of the expansion of the Universe.

More information:

The Hubble Space Telescope is a project of international cooperation between ESA and NASA.

The team of astronomers in this study consists of Adam G. Riess (Johns Hopkins University, USA; STScI, USA), Stefano Casertano (STScI, USA), Wenlong Yuan (Johns Hopkins University, USA), Lucas M. Macri (Texas A&M University, USA), Dan Scolnic (Duke University, USA).

Links:

Hubblecast 120 Light: Continued Discrepancy in the Universe's Expansion Rate: https://www.spacetelescope.org/videos/heic1908a/

Images of Hubble: http://www.spacetelescope.org/images/archive/category/spacecraft/

Hubblesite release: http://hubblesite.org/news_release/news/2019-25

Johns Hopkins University release: http://releases.jhu.edu/2019/04/25/new-hubble-measurements-confirm-universe-is-outpacing-all-expectations-of-its-expansion-rate/

Araucaria Project: https://en.wikipedia.org/wiki/Araucaria_Project

Planck satellite: https://www.esa.int/Our_Activities/Space_Science/Planck

NASA/ESA Hubble Space Telescope: https://www.spacetelescope.org/

Images, Animation, Text, Credits: ESA/Hubble/Bethany Downer/Space Telescope Science Institute/Adam Riess/Acknowledgement: Josh Lake/ESO/Robert Gendler/Video Credits: NASA, ESA, A. Feild (STScI), and A. Riess (STScI/JHU).

Best regards, Orbiter.ch

The first Chinese on the Moon in ten years?













CLEP - China Lunar Exploration Program logo.

April 25, 2019

Beijing aims to build a scientific research station in the regions of the South Pole of the Moon in about ten years.

Taikonauts on the Moon in 2029? (Photo-montage, illustation) Image Credits: NASA/Apollo 11

The announcement comes as China has achieved in January a world first: the moon landing of a probe on the far side of the moon.

China will send a first manned mission to the moon "in a decade," said China's top space program chief, while the United States aims to return to lunar soil by 2024.

"China aims to build a scientific research station in the regions of the South Pole of the Moon and to carry out manned lunar missions in a decade," said the director of the National Administration of Space, Zhang Kejian, quoted by the news agency China News.

Beijing has for many years evoked an inhabited mission on the Moon but no precise date has ever been provided, experts usually rely on a date after 2025.

After a successful lunar landing

Mr. Zhang's announcement comes as the country has achieved a world premiere at the start of the year: the moon landing of a probe on the far side of the moon. The communist regime relies heavily on its space programs to glorify the country's technological progress in recent decades, in a race with the West that evokes Soviet-American space rivalry during the Cold War.


Animation above: Yutu-2 rover leave Chang'e-4 lander and start exploring the Von Karman Crater. Animation Credits: CNSA / CLEP / Orbiter.ch Aerospace / Roland Berga.

The words of the Chinese leader come less than a month after Washington announced a return of American astronauts to the moon in 2024, instead of 2028 as originally planned. The United States was the first and only one to send men to the moon between 1969 and 1972.

Zhang said Beijing plans to send its first probe to Mars next year. In addition to the probe currently on the far side of the moon, China also plans to send at the end of this year another machine responsible for bringing lunar samples back to Earth, he said.

Yutu-2 Lunar Rover. Image Credits: CNSA / CLEP

Witnessing the political dimension of these missions, Zhang said that lunar samples would be kept in Shaoshan (center), the hometown of Mao Tse-tung, the founder of the communist regime. China sent a first man into space in 2003 and achieved his first landing of a spacecraft 10 years later.

Related articles & links:

China's Chang'e-4 Probe Wakes Up after First Lunar Night
https://orbiterchspacenews.blogspot.com/2019/02/chinas-change-4-probe-wakes-up-after.html

China's Yutu-2 rover Enters Standby Mode for 'Noon Nap' as Chang'e 4 Tests Continue
https://orbiterchspacenews.blogspot.com/2019/01/chinas-yutu-2-rover-enters-standby-mode.html

Sending American Astronauts to Moon in 2024: NASA Accepts Challenge
https://orbiterchspacenews.blogspot.com/2019/04/sending-american-astronauts-to-moon-in.html

For more information about China Aerospace Science and Technology Corporation (CASC), visit: http://english.spacechina.com/n16421/index.html

For more information about China National Space Administration (CNSA), visit: http://www.cnsa.gov.cn/

Images (mentioned), Animation (mentioned), Text, Credits: AFP/CNSA/CLEP/Orbiter.ch Aerospace/Roland Berga.

Greetings, Orbiter.ch

mercredi 24 avril 2019

More Head and Eye Pressure Research and Dragon Robotics Training











ISS - Expedition 59 Mission patch.

April 24, 2019

The Expedition 59 crew is unloading one U.S. cargo ship today and preparing for the arrival of another after it launches from Florida next week. The orbital residents also continued exploring how microgravity impacts the human body and a variety of terrestrial materials.

Astronauts Christina Koch and David Saint-Jacques worked Wednesday afternoon to offload some of the 7,600 pounds of cargo the Cygnus space freighter delivered last week. Saint-Jacques is also training today to capture the SpaceX resupply ship with the Canadarm2 robotic arm when it arrives next Thursday. Dragon will be the sixth spaceship parked at the station and occupy the Harmony module’s Earth-facing port.


Image above: Astronauts David Saint-Jacques and Anne McClain practice Canadarm2 robotics maneuvers and spacecraft capture techniques on the robotics workstation in the U.S. Destiny laboratory module. Image Credit: NASA.

The duo also split the day working with a variety of biomedical hardware and research gear to ensure healthy astronauts and successful space research. Koch and Saint-Jacques participated in ultrasound scans for ongoing health checks. Koch then explored the feasibility of manufacturing fiber optic cables in space. Saint-Jacques set up Kubik incubator hardware inside Europe’s Columbus lab module.

International Sapce Station (ISS). Animation Credit: NASA

NASA Flight Engineers Anne McClain and Nick Hague were back collecting more blood, urine and saliva samples today. The samples are spun in a centrifuge, stowed in a science freezer then analyzed for the long-running Fluid Shifts study. The experiment seeks to understand and prevent the upward flow of body fluids in space that cause head and eye pressure in astronauts.

McClain then studied how living aboard the International Space Station affects her perception and cognition. Hague researched and photographed a variety of coating materials for their thermal protection and optical recognition properties.

Related links:

Expedition 59: https://www.nasa.gov/mission_pages/station/expeditions/expedition59/index.html

Canadarm2 robotic arm: https://www.nasa.gov/mission_pages/station/structure/elements/mobile-servicing-system.html

Harmony module: https://www.nasa.gov/mission_pages/station/structure/elements/harmony

Space research: https://www.nasa.gov/mission_pages/station/research/index.html

Fiber optic cables: http://www.asc-csa.gc.ca/eng/astronauts/canadian/active/bio-david-saint-jacques.asp

Columbus lab module: https://www.nasa.gov/mission_pages/station/structure/elements/europe-columbus-laboratory

Fluid Shifts: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1126

Perception and cognition: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=979

Coating materials: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1749

Space Station Research and Technology: https://www.nasa.gov/mission_pages/station/research/index.html

International Space Station (ISS): https://www.nasa.gov/mission_pages/station/main/index.html

Image (mentioned), Animation (mentioned), Text, Credits: NASA/Mark Garcia.

Best regards, Orbiter.ch