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Sonntag, 3. September 2017 - 16:20 Uhr

Raumfahrt - Rückkehr von ISS-Crew mit Soyuz MS-04 und Landung in Kasachstan

3.09.2017

Soyuz MS-04 descent module lands in Kazakhstan

The spacecraft carries Russian cosmonaut Fyodor Yurchikhin and NASA astronauts Peggy Whitson and Jack Fischer

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Russian cosmonaut Fyodor Yurchikhin

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The descent module of Russia’s Soyuz MS-04 spacecraft with three people on board landed in Kazakhstan early on Sunday, the Russian Mission Control center said.

"Landing done," a speaker of the Mission Control Center announced.

The three international crew members have been safely evacuated from the descent capsule minutes after the landing.

"All the three Soyuz MS-04 crew members have been successfully evacuated, they are in good health," the Russian Mission Control Center said.

 

Russia’s Federal Aviation Agency deployed two An-12 and one An-26 planes and 12 Mi-8 helicopters, as well as six search and rescue vehicles and other auxiliary equipment to ensure safe landing.

The Soyuz MS-04 spacecraft with Russian cosmonaut Fyodor Yurchikhin and NASA astronauts Peggy Whitson and Jack Fischer on board undocked from the ISS at 00:58 Moscow time on Sunday.

Whitson arrived to the International Space Station on November 17, 2016 and spent nearly one year on the orbit. Yurchikhin and Fischer arrived to the ISS on April 20, 2017, and their mission lasted 135 days.

The ISS crew will comprise Russian cosmonaut Sergey Ryazansky, NASA astronaut Randolph Bresnik and ESA astronaut Paolo Nespoli. They are to be joined by Russia’s Aleksandr Misurkin, and NASA’s Mark Vande Hei and Joseph Acaba, whose Soyuz MS-06 is due to blast off on September 13.

Quelle: TASS

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Record-breaking U.S. astronaut and crew back on Earth

 
CAPE CANAVERAL, Fla (Reuters) - NASA astronaut Peggy Whitson and two crewmates made a parachute touchdown in Kazakhstan on Saturday, capping a career-total 665 days in orbit, a U.S. record. 

Whitson, 57, ended an extended stay of more than nine months aboard the International Space Station, a $100 billion research laboratory that flies about 250 miles (400 km) above Earth. 

”I feel great,” the biochemist said during an inflight interview on Monday. “I love working up here. It’s one of the most gratifying jobs I’ve ever had.” 

During her third mission aboard the station, Whitson spent much of her time on experiments, including studies of cancerous lung tissue and bone cells. She also completed four spacewalks, adding to her six previous outings, to set a record for the most time spent spacewalking by a woman. 

Two crewmates who launched with Whitson in November returned to Earth three months ago. She stayed aboard to fill a vacancy after Russia scaled down its station staff from three to two cosmonauts. 

Whitson returned to Earth with Jack Fischer, also with the National Aeronautics and Space Administration, and Russian cosmonaut Fyodor Yurchikhin, who had been aboard the station since June. 

 

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The crew’s Russian Soyuz capsule touched down in Kazakhstan at 9:21 p.m. EDT Saturday. 

”I’m looking forward to seeing friends and family,” Whitson said during another interview. 

 

“But the thing I’ve been thinking about the most, kind of been fantasizing about a little bit, are foods that I want to make, vegetables that I want to sauté, things that I’ve missed up here.” 

In April, Whitson broke the 534-day U.S. record for cumulative time in space. Only seven Russian men have logged more time, including Gennady Padalka, the world record-holder with 878 days in orbit. 

Whitson, who grew up on a farm in Iowa, said she was inspired by the U.S. Apollo program that landed men on the moon, but it was not until later, when the first women become astronauts, that she set her sights on joining them. 

Whitson, who became an astronaut in 1996, was the first woman to command the space station and also the first woman and first non-pilot to serve as chief of the NASA Astronaut Corps. 

“I am working on paying forward some of the advice and mentoring that I received on my journey, in hopes that one day those young people will do the same and look back on a life in which they leapt at the opportunities and broke their own records,” she said.

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Three International Space Station Crewmates Safely Return to Earth

NASA astronaut Peggy Whitson, Russian cosmonaut Fyodor Yurchikhin of Roscosmos, and NASA astronaut Jack Fischer
NASA astronaut Peggy Whitson, Russian cosmonaut Fyodor Yurchikhin of Roscosmos, and NASA astronaut Jack Fischer undergo routine initial medical checks after returning from their mission aboard the International Space Station at 9:21 p.m. EDT Saturday (7:21 a.m. Kazakhstan time, Sunday, Sept. 3), landing southeast of the remote town of Dzhezkazgan in Kazakhstan.
Credits: NASA TV
 Soyuz MS-04 carrying NASA astronauts Peggy Whitson and Jack Fischer and Fyodor Yurchikin of Roscosmos
The Soyuz MS-04 carrying NASA astronauts Peggy Whitson and Jack Fischer and Fyodor Yurchikin of Roscosmos back to Earth from the International Space Station touched down at at 9:21 p.m. EDT Saturday, Sept. 2 (7:21 a.m. Kazakhstan time, Sunday, Sept. 3), southeast of the remote town of Dzhezkazgan in Kazakhstan.
Credits: NASA TV

NASA astronaut Peggy Whitson, who set multiple U.S. space records during her mission aboard the International Space Station, along with crewmates Jack Fischer of NASA and Commander Fyodor Yurchikhin of Roscosmos, safely landed on Earth at 9:21 p.m. EDT Saturday (7:21 a.m. Kazakhstan time, Sunday, Sept. 3), southeast of the remote town of Dzhezkazgan in Kazakhstan.

 

While living and working aboard the world’s only orbiting laboratory, Whitson and Fischer contributed to hundreds of experiments in biology, biotechnology, physical science and Earth science, welcomed several cargo spacecraft delivering tons of supplies and research experiments, and conducted a combined six spacewalks to perform maintenance and upgrades to the station.

 

Among their scientific exploits, Whitson and Fischer supported research into the physical changes to astronaut’s eyes caused by prolonged exposure to a microgravity environment. They also conducted a new lung tissue study that explored how stem cells work in the unique microgravity environment of the space station, which may pave the way for future stem cell research in space.

 

Additional research included an antibody investigation that could increase the effectiveness of chemotherapy drugs for cancer treatment, and the study of plant physiology and growth in space using an advanced plant habitat. NASA also attached the Cosmic Ray Energetics and Mass Investigation (ISS CREAM) on the outside of the space station in August, which is now observing cosmic rays coming from across the galaxy.

 

The crew members received a total of seven cargo deliveries during their mission. A Japanese H-II Transfer Vehicle launched to the space station in December 2016 delivering new lithium-ion batteries that were installed using a combination of robotics and spacewalks. Orbital ATK’sCygnus spacecraft arrived at the station in April on the company's seventh commercial resupply mission. Three SpaceX Dragon spacecraft completed commercial resupply missions to the station in February, June and August. And, Russian ISS Progress cargo spacecraft docked to the station in February and June.

 

Whitson’s return marks the completion of a 288-day mission that began last November and spanned 122.2 million miles and 4,623 orbits of the Earth – her third long-duration mission on the station. During her latest mission, Whitson performed four spacewalks, bringing her career total to 10. With a total of 665 days in space, Whitson holds the U.S. record and places eighth on the all-time space endurance list.

 

Fischer, who launched in April, completed 136 days in space, during which he conducted the first and second spacewalks of his career. Yurchikhin, who launched with Fischer, now has a total of 673 days in space, putting him seventh place on the all-time endurance list.

 

Expedition 53 continues operating the station, with Randy Bresnik of NASA in command, and Sergey Ryazanskiy of Roscosmos and Paolo Nespoli of ESA (European Space Agency) serving as flight engineers. The three-person crew will operate the station until the arrival of NASA astronauts Mark Vande Hei and Joe Acaba, and Alexander Misurkin of Roscosmos. Vande Hei, Acaba and Misurkin are scheduled to launch Sept. 12 from Baikonur, Kazakhstan.

Quelle: NASA

 

 

 





Tags: Raumfahrt - Rückkehr von ISS-Crew mit Soyuz MS-04 und Landung in Kasachstan 

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Samstag, 2. September 2017 - 21:15 Uhr

Astronomie - Äquatorial-Jet in der Venus-Atmosphäre von Akatsuki entdeckt

2.09.2017

Equatorial jet in Venusian atmosphere discovered by Akatsuki

Observations by Japan’s Venus climate orbiter Akatsuki have revealed an equatorial jet in the lower to middle cloud layer of the planet’s atmosphere, a finding that could be pivotal to unraveling a phenomenon called superrotation.

 

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An illustration of Akatsuki successfully tracking lower-altitude clouds during the night with its near-infrared camera IR2. ©PLANET-C Project Team

 

Venus rotates westward with a very low angular speed; it takes 243 Earth days to rotate once. The planet’s atmosphere rotates in the same direction but at much higher angular speeds, which is called “superrotation.” The planet is covered by thick clouds that extend from an altitude of about 45 kilometers to 70 kilometers. The superrotation reaches its maximum near the top of this cloud, where the rotational speed is about 60 times that of the planet itself. The cause of this phenomenon, however, is shrouded in mystery.

 

Akatsuki was launched in 2010 by the Japan Aerospace Exploration Agency to unravel the atmospheric mysteries of Venus. Although lower-altitude clouds cannot be seen through with visible light, Akatsuki’s near-infrared camera IR2 successfully tracked the clouds – in particular, thicker clouds between 45 kilometers to 60 kilometers in altitude. This was made possible by observing the silhouettes of clouds that appear when infrared light from thermal radiation originating in the lower atmosphere filter through clouds.

 

Slides showing two-hourly 2.26-μm radiance obtained by the IR2 camera onboard Akatsuki on July 11-12, 2016. The brightness is shown reversely (see the color bar at the bottom shown in the units of W m-2 sr-1 μm-1), so the brighter areas represent fewer radiance, indicating thicker clouds. Remark: The original images between 18 and 22 h include the dayside of Venus in the observational field of view, so the radiance change near the day-night boundary in the middle of the images is spurious owing to the dayside brightness. ©PLANET-C Project Team

 

Similar observations were previously made by the Venus Express orbiter of the European Space Agency and Galileo spacecraft of the U.S. National Aeronautics and Space Administration, but they provided only limited data of the planet’s low-latitude zones. From these observations, scientists speculated that wind speeds at lower-to-middle cloud altitudes are horizontally uniform and have few temporal variations.

 

In the study published in Nature Geoscience, the team of researchers including Hokkaido University Associate Professor Takeshi Horinouchi analyzed the data collected by Akatsuki between March and August 2016. The team employed a cloud-tracking method they recently developed to deduce horizontal distributions of winds based on data from Akatsuki.

 

They discovered an equatorial jet in the wind velocities based on image data from July 2016 and that the jet existed at least two months after that. In March that year, the wind velocities in the same latitude zones were rather slow – thus there was no jet.

 

Westward wind speed obtained from the IR2 observations on July 11-12, 2016; longitudinally averaged winds are shown with respect to latitude. The wind speed peaks at low latitude indicating the jet. ©PLANET-C Project Team

 

The findings showed for the first time that wind velocities can be markedly high forming a jet near the equator, which have never been found not only in the scantily observed lower to middle cloud layers but also in the more-extensively studied high layers.

 

“Our study uncovered that wind velocities in the lower-to-middle cloud layer have temporal and spatial variabilities much greater than previously thought,” says Takeshi Horinouchi. “Although it remains unclear why such an equatorial jet appears, the mechanisms that could cause it are limited and related to various theories about superrotation. So, further study of the Akatsuki data should help glean useful knowledge not only about local jets but also would help address superrotation theories.”

Quelle: HOKKAIDO University


Tags: Astronomie - Äquatorial-Jet in der Venus-Atmosphäre von Akatsuki entdeckt 

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Samstag, 2. September 2017 - 21:00 Uhr

Astronomie - Die Ringe des Uranus enthüllen Geheimniss des Cressida Mond

2.09.2017

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f you could put Uranus’ moon Cressida in a gigantic tub of water, it would float.

Cressida is one of at least 27 moons that circle Uranus. Robert Chancia of the University of Idaho in Moscow and colleagues calculated Cressida’s density and mass using variations in an inner ring of the planet as Uranus passed in front of a distant star. The team found that the density of the moon is 0.86 grams per cubic centimeter and its mass is 2.5x1017 kilograms. The results, reported August 28 on arXiv.org, are the first to reveal details about the moon. Knowing its density and mass helps researchers determine if and when Cressida might collide with another of Uranus’ moons and what will become of both of them.

Voyager 2 discovered Cressida and several other moons when the spacecraft flew by Uranus in 1986. Those moons, and two discovered later, orbit within 20,000 kilometers of Uranus and are the most tightly packed in the solar system.

Such close quarters puts the moons on collision courses. Based on the newly calculated mass and density of Cressida, simulations suggest it will slam into another moon, Desdemona, in a million years.

Cressida’s density suggests it is made of water ice with some contamination by a dark material. If the other moons have similar compositions, the moon collisions may happen in the more distant future than researchers thought. Determining what the moons are made of will also reveal their ultimate fate after a collision: whether they merge, bounce off each other or shatter into millions of pieces.

Quelle: ScienceNews

 

 

Tags: Astronomie - Die Ringe des Uranus enthüllen Geheimniss des Cressida Mond 

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Samstag, 2. September 2017 - 20:20 Uhr

Astronomie - Hubble liefert erste Hinweise auf mögliche Wasserspuren von TRAPPIST-1 Planeten

2.09.2017

Hubble delivers first hints of possible water content of TRAPPIST-1 planets

 

 

An international team of astronomers used the NASA/ESA Hubble Space Telescope to estimate whether there might be water on the seven earth-sized planets orbiting the nearby dwarf star TRAPPIST-1. The results suggest that the outer planets of the system might still harbour substantial amounts of water. This includes the three planets within the habitable zone of the star, lending further weight to the possibility that they may indeed be habitable.

On 22 February 2017 astronomers announced the discovery of seven Earth-sized planets orbiting the ultracool dwarf star TRAPPIST-1, 40 light-years away [1]. This makes TRAPPIST-1 the planetary system with the largest number of Earth-sized planets discovered so far.

Following up on the discovery, an international team of scientists led by the Swiss astronomer Vincent Bourrier from the Observatoire de l’Université de Genève, used the Space Telescope Imaging Spectrograph (STIS) on the NASA/ESA Hubble Space Telescope to study the amount of ultraviolet radiation received by the individual planets of the system. “Ultraviolet radiation is an important factor in the atmospheric evolution of planets,” explains Bourrier. “As in our own atmosphere, where ultraviolet sunlight breaks molecules apart, ultraviolet starlight can break water vapour in the atmospheres of exoplanets into hydrogen and oxygen.”

While lower-energy ultraviolet radiation breaks up water molecules — a process called photodissociation — ultraviolet rays with more energy (XUV radiation) and X-rays heat the upper atmosphere of a planet, which allows the products of photodissociation, hydrogen and oxygen, to escape.

As it is very light, hydrogen gas can escape the exoplanets’ atmospheres and be detected around the exoplanets with Hubble, acting as a possible indicator of atmospheric water vapour [2]. The observed amount of ultraviolet radiation emitted by TRAPPIST-1 indeed suggests that the planets could have lost gigantic amounts of water over the course of their history.

This is especially true for the innermost two planets of the system, TRAPPIST-1b and TRAPPIST-1c, which receive the largest amount of ultraviolet energy. “Our results indicate that atmospheric escape may play an important role in the evolution of these planets,” summarises Julien de Wit, from MIT, USA, co-author of the study.

The inner planets could have lost more than 20 Earth-oceans-worth of water during the last eight billion years. However, the outer planets of the system — including the planets e, f and g which are in the habitable zone — should have lost much less water, suggesting that they could have retained some on their surfaces [3]. The calculated water loss rates as well as geophysical water release rates also favour the idea that the outermost, more massive planets retain their water. However, with the currently available data and telescopes no final conclusion can be drawn on the water content of the planets orbiting TRAPPIST-1.

“While our results suggest that the outer planets are the best candidates to search for water with the upcoming James Webb Space Telescope, they also highlight the need for theoretical studies and complementary observations at all wavelengths to determine the nature of the TRAPPIST-1 planets and their potential habitability,” concludes Bourrier.

Notes

[1] The planets were discovered using: the ground-based TRAPPIST-South at ESO’s La Silla Observatory in Chile; the orbiting NASA Spitzer Space TelescopeTRAPPIST-North in Morocco; ESO’s HAWK-I instrument on the Very Large Telescope at the Paranal Observatory in Chile; the 3.8-metre UKIRT in Hawaii; the 2-metre Liverpool and 4-metre William Herschel telescopes at La Palma in the Canary Islands; and the 1-metre SAAO telescope in South Africa.

[2] This part of an atmosphere is called the exosphere. Earth’s exosphere consists mainly of hydrogen with traces of helium, carbon dioxide and atomic oxygen.

[3] Results show that each of these planets have may have lost less than three Earth-oceans of water.

Quelle: ESA


Tags: Astronomie - Hubble liefert erste Hinweise auf mögliche Wasserspuren von TRAPPIST-1 Planeten 

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Samstag, 2. September 2017 - 20:10 Uhr

Raumfahrt - Roscosmos plant 3 Stunden-Flug zur ISS mit Progress MS-07

2.09.2017

Two-orbit manned trips to ISS possible after Progress cargo craft's test flights

 

The two-orbit flight will last three hours

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Russia’s space corporation Roscosmos may consider the possibility of using a two-orbit pattern (lasting three hours from lift-off to docking) for the manned Soyuz MS spacecraft taking crews to the ISS after a series of tests involving the unmanned cargo spacecraft Progress, a Roscosmos spokesman said.

"After the two-orbit trip pattern has been tested with the use of Progress MS cargo craft, the documentation will be analyzed and amended. The possibility of using the two-orbit flight path for launching manned Soyuz spacecraft to the ISS will be considered only after that," the official said.

Earlier, Roscosmos said that the cargo spacecraft Progress MS-07, due to be put in space from the Baikonur space site in Kazakhstan with a Soyuz 2.1a rocket on October 12, will for the first time reach the ISS within three hours after orbiting the Earth twice. The corporation added that the spacecraft would use an experimental flight path.

The current fastest pattern of sending cargo and manned spacecraft to the USS continues for six hours. Still earlier, it took spacecraft two days to reach the ISS.

 

The two-orbit flight will last three hours. Under the current six-hour pattern the spacecraft orbits the Earth four times.

Quelle: TASS








Tags: Raumfahrt - Roscosmos plant 3 Stunden-Flug zur ISS mit Progress MS-07  

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Samstag, 2. September 2017 - 20:10 Uhr

Raumfahrt - Fehlstart von ISRO´s PSLV-C39 mit IRNSS-1H Satelliten

24.08.2017

ISRO to launch a new navigation satellite on August 31

The IRNSS-1H, which will replace the IRNSS-1A, will be launched on board ISRO's work horse rocket the PSLV-C39 and the new satellite "will augment the existing seven satellites of NavIC constellation", ISRO said on Wednesday.

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The Indian Space Research Organization (ISRO) will launch a new navigation satellite into space on August 31 to replace the IRNSS-1A in a seven-satellite Indian navigation constellation following the failure of the IRNSS-1A due to deficiencies in three atomic clocks on the satellite that are crucial to providing positional information to users on earth.

The IRNSS-1H, which will replace the IRNSS-1A, will be launched on board ISRO’s work horse rocket the PSLV-C39 and the new satellite “will augment the existing seven satellites of NavIC constellation”, ISRO said on Wednesday.

Earlier this year, ISRO had stated that three Rubidium Atomic Frequency Standard (RAFS) clocks on the IRNSS 1A, the first of the seven IRNSS satellites that was launched on July 1, 2013, had malfunctioned, rendering the satellite ineffective. ISRO had originally indented for nine satellites in its Indian Regional Navigation Satellite System costing Rs 1,420 crore to service the global positioning data needs of the civilian sector and the Indian defence forces. While seven satellites were to form the Navigation Indian Constellation or NavIC, two satellites were meant to be replacements.

The atomic clocks in the new satellite are modified versions of the original clocks provided by an European supplier under a $4 million euro deal which were found deficient. Three similar clocks used in satellites for the European Galileo satellite system also reported similar problems.

ISRO has been carrying out modifications of clocks — procured from the European firm Spectratime — since 2008 to overcome technical issues. Investigations of malfunctioning clocks by the European Space Agency have revealed that a faulty component may be causing short circuits.

One of the primary reasons for the development of the indigenous Indian satellite navigation system like the IRNSS despite the existence of global systems like the Global Positioning System of the US, the Russian GLONASS, the European Galileo and the Chinese Beidou is the reliability that it offers when used for defence purposes. Accurate time keeping lies at the heart of navigation systems since the determination of a person’s position on earth is subject to the accurate calculation of delays in signal transmission from the satellite to earth. Small errors in clocks can skew position data by several hundred kilometres.

On each of the IRNSS satellites there are three atomic clocks, with one acting as the primary time-keeper and the other two being in back-up mode. The failure of all three clocks on a satellite will render the satellite ineffective in providing positional information.

While three atomic clocks have failed on the 18 satellite European Galileo system, no satellite has been lost since the back-up clocks on the satellites have been in operation. “In recent months, a total of three RAFS clocks unexpectedly failed on Galileo satellites — all on Full Operational Capability satellites, the latest Galileo model. These failures seem to have a consistent signature, linked to probable short circuits, and possibly a particular test procedure performed on the ground,” ESA stated in January this year.

ISRO started work on the Rs 1,420 crore IRNSS programme in 1999 after the Kargil war where Indian defence forces could not use American GPS in the conflict zone to locate its soldiers.

The IRNSS positioning system is intended to provide two services — Standard Positioning Service (SPS) for general users and a Restricted Service (RS), which is an encrypted service provided only for authorised users like the defence forces.

NavIC is designed to provide accurate position information service to users in India as well as a region extending up to 1500 km from its boundary.

Quelle: The Indian Express

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Update: 30.08.2017

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ISRO: Countdown for launch of Indian replacement navigation satellite from today

The 29-hour countdown for the Thursday evening launch of India's navigation satellite IRNSS-1H using the rocket Polar Satellite Launch Vehicle (PSLV) will begin on Wednesday, ISRO said on Tuesday.

ISRO, Indian navigation satellite, NavIC, IRNSS-1H, PSLV, Satish Dhawan Space Centre, INRSS satellite, INRSS-1A replacement, atomic clock failure, atomic clock modification, ISRO launchAccording to Indian Space Research Organisation (ISRO), the Mission Readiness Review (MRR) committee and Launch Authorisation Board (LAB) have cleared the 29-hour countdown to begin at 2 p.m. on Wednesday. (Image Credit: ISRO)

The 29-hour countdown for the Thursday evening launch of India’s navigation satellite IRNSS-1H using the rocket Polar Satellite Launch Vehicle (PSLV) will begin on Wednesday, ISRO said on Tuesday. According to Indian Space Research Organisation (ISRO), the Mission Readiness Review (MRR) committee and Launch Authorisation Board (LAB) have cleared the 29-hour countdown to begin at 2 p.m. on Wednesday.

India on Thursday will at 7 pm. launch its navigation satellite IRNSS-1H (Indian Regional Navigation Satellite System) weighing 1,425 kg with its PSLV rocket. This eighth IRNSS satellite will be the replacement for IRNSS-1A, as its atomic clocks have failed.

As reported by The Indian Express, the atomic clocks in the new satellite are modified versions of the original clocks provided by an European supplier under a $4 million euro deal which were found deficient. Three similar clocks used in satellites for the European Galileo satellite system also reported similar problems. The PSLV rocket will sling the IRNSS-1H into a Sub-Geosynchronous Transfer Orbit. 

As Indian Express had reported, earlier this year, ISRO had stated that three Rubidium Atomic Frequency Standard (RAFS) clocks on the IRNSS 1A, the first of the seven IRNSS satellites that was launched on July 1, 2013, had malfunctioned, rendering the satellite ineffective. While seven satellites were to form the Navigation Indian Constellation or NavIC, two satellites were meant to be replacements.

The IRNSS positioning system is intended to provide two services — Standard Positioning Service (SPS) for general users and a Restricted Service (RS), which is an encrypted service provided only for authorised users like the defence forces. NavIC is designed to provide accurate position information service to users in India as well as a region extending up to 1500 km from its boundary.

The 1.4-tonne satellite will be launched from the state-run Indian Space Research Organisation’s (ISRO) spaceport at the Satish Dhawan Space Centre (SDSC) in Sriharikota in Andhra Pradesh, about 80 km northeast of Chennai. The launch will take place from the second launch pad of Satish Dhawan Space Centre (SDSC) SHAR.

Quelle: The Indian Express

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ISRO begins countdown to the launch of IRNSS 1H 

The IRNSS 1 H will form part of the NavIC that is India’s own version of GPS that helps in everything from navigation of ships, to traffic management to locating restaurants.

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ISRO scientists prepare for the launch of IRNSS 1 H on the PSLV satellite launch vehicle.(Courtesy: ISRO)

At 7 pm on Aug 31, ISRO will launch the IRNSS 1 H, a satellite that will augment India’s indigenous GPS system called NavIC (Navigation with Indian Constellation), from the Satish Dhawan Space Centre at Sriharikota.

There are seven satellites in the NavIC system currently, all launched between 2013 and 2016. The IRNSS 1 H launch was necessitated by a malfunction in the IRNSS 1A, the first satellite to be launched in this series. By mid-2016 problems surfaced with the atomic clocks onboard the satellite that helps keep time with a high degree of accuracy. It is an essential part of a navigational system.

Each satellite in the IRNSS series has three atomic clocks, one primary and two back ups. All 21 clocks that are currently onboard these satellites are manufactured by Spectracom, which is part of the Orolia Group, a conglomerate headquartered in the United States. 

The atomic clocks onboard the IRNSS 1H are also from Spectracom, supplied by their manufacturing plant in Switzerland. These are rubidium-based atomic clocks, that have a high degree of accuracy unlike the electronic clocks used by earth-dwelling folk. These clocks do not lose or gain even a single second over millions of years.

“We identified the problem and the new clocks have the necessary corrections, they are purely technical in nature,” Deviprasad Karnik, spokesperson for ISRO, said but declined to shed light on the nature of the problem or the corrections.

An official at Spectrocom who spoke on the condition of anonymity said that no design changes had been made to the clocks as per his knowledge. He explained that atomic clocks like the one onboard the IRNSS could fail for many reasons including lack of improper voltage being supplied to the clock.

The IRNSS 1H will not exactly displace the IRNSS 1 A which has been relaying fuzzy data since the clock failures but rather be used in tandem.

The Rubidium atomic clocks form part of the navigation payload and the IRNSS 1H will be used for navigation services while the IRNSS-1A will continue to be used for messaging services.

 

The main applications of NavIC are in:

Shipping: Merchant ships use them for navigation and also for disaster management on the high seas.

Road Transport: It is used for navigation on roads as well as helping operators track their consignments and for traffic management by government agencies.

Railways: NavIC is also used to track train movements and for estimating time of arrival and departure. 

Resource Management: These satellites inform the geo-tagging and geo-fencing of objects that help entrepreneurs and governments track if there is movement of goods beyond designated boundaries.

Location Based Services: Navigational satellites are essential to operations like finding nearby restaurants, shops, hospitals and petrol pumps.

Time Synchronised Services: NavIc is also used in telecom operations, power grid operations, disaster management and atmospheric studies.

Quelle: hindustantimes

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Update: 2.09.2017

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PSLV launch of navigation satellite fails

 

Updated 6:45 p.m. Eastern.

LOS ANGELES — An Indian Polar Satellite Launch Vehicle (PSLV) failed to place a navigation satellite into its planned orbit Aug. 31 when the rocket’s payload fairing failed to deploy.

The PSLV, flying a mission designated PSLV-C39, lifted off on schedule at 9:30 a.m. Eastern from the Satish Dhawan Space Centre on the east coast of India. Initial phases of the launch appeared to go as planned, but observers noted that, as the flight progressed, the vehicle appeared to deviate from its planned trajectory according to telemetry displays shown during the webcast.

 

Launch controllers later confirmed that vehicle’s upper stage and payload, the Indian Regional Navigation Satellite System (IRNSS) 1H satellite, had reached a lower orbit than planned. The payload was in an orbit of 167 by 6,555 kilometers, while the planned transfer orbit for the mission was 284 by 20,650 kilometers.

A launch controller later confirmed that the rocket’s payload fairing, scheduled to separate 3 minutes and 23 seconds after liftoff during the operation of the rocket’s upper stage, had failed to do so. The additional mass of the payload fairing may account for the apparent underperformance of the PSLV’s upper stages, and would also prevent the satellite’s deployment regardless of orbit.

The Indian space agency ISRO did not immediately comment on the failure. An ISRO webcast of the launch abruptly ended shortly after the announcement of the failed payload fairing separation.

ISRO, in a statement later Aug. 31, confirmed that the payload fairing, which it calls the “heat shield,” failed to separate, dooming the mission. “[A]ll the flight events took place exactly as planned, except heat shield separation,” the agency said. “This resulted in satellite separation occurring within the heat shield. The satellite is inside the heat shield resulting in the unsuccessful mission.”

The failure is the first for the PSLV in 20 years. In September 1997, a PSLV launch placed the IRS-1D remote sensing satellite into a lower-than-planned orbit when the rocket’s fourth stage underperformed. The satellite was able to use its onboard propulsion to raise its orbit. The only total PSLV failure was rocket’s inaugural flight in September 1993, when it suffered an attitude control failure.

The failure would be a significant setback for India’s space program. The PSLV had become the workhorse for the program, launching a series of communications, remote sensing, navigation and science satellites. India had been working to increase the vehicle’s launch rate. The PSLV flew six times in 2016, and this was the third PSLV mission of 2017.

PSLV had also become a popular choice for small satellite developers, who took advantage of frequent launches to sun-synchronous orbits and excess capacity on those missions to fly as secondary payloads. A PSLV launch in February set a record for the most satellites on a single flight, with 104 payloads; all but three were cubesats provided by international customers.

The sole payload of this launch, IRNSS-1H, was intended to be a replacement for India’s first navigation satellite, IRNSS-1A, whose three onboard atomic clocks had failed. The overall IRNSS system provides position, navigation and timing data for India and the surrounding region.

Quelle: SN

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Indian PSLV launch with IRNSS replacement satellite suffers apparent failure

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ISRO launched a PSLV Thursday carrying a replacement satellite for the Indian Regional Navigation Satellite System (IRNSS) constellation. The IRNSS-1H satellite launched on schedule from the Second Launch Pad (SLP) at the Satish Dhawan Space Centre at 19:00 local time (13:30 UTC). However, the launch profile was off-nominal and the fairing failed to separate leading to an apparent failure of the mission.

PSLV Launch:

The IRNSS-1H spacecraft was to be the eighth to be launched as part of India’s Indian Regional Navigation Satellite System (IRNSS), or NavIC, program. One of two ground spares built for the seven-satellite constellation, IRNSS-1H is being pressed into service after the failure of all three atomic clocks aboard the first IRNSS satellite, IRNSS-1A.

The second ground spare, IRNSS-1I, is also expected to launch later this year. Two further ground spares are under construction. IRNSS satellites are built and operated by the Indian Space Research Organisation, ISRO.

2016-04-28-040744

IRNSS uses a constellation of seven spacecraft in geosynchronous orbit to provide a navigation service covering most of Asia, the Middle East, east Africa and parts of western Australia. The program gives India a dedicated navigation system, serving military and civilian applications, reducing the country’s reliance on systems controlled by foreign governments.

Satellite navigation relies on precision timing provided by several highly-accurate atomic clocks aboard each spacecraft – three rubidium clocks in the case of an IRNSS satellite. The time of transmission is encoded in signals broadcast by a satellite, which receivers can use to work out the time taken for the signals to reach it – and hence the receiver’s distance from the spacecraft.

By triangulating the distance of the receiver from four satellites, whose precise locations in space are known through orbital ephemeris broadcast along with the timing data, a location can be computed in three dimensions.

The problems aboard IRNSS-1A began in mid-2016 with the failure of one of its three atomic clocks. The remaining two failed over the following six months.

Without the clocks in operation the satellite cannot produce a sufficiently accurate signal to be used for precise navigation, although it is continuing to broadcast system messages. At launch in July 2013, the spacecraft was expected to provide ten years of service.

The clocks aboard IRNSS satellites were built by Swiss company SpectraTime. Several satellites in the European Galileo navigation constellation, which also uses rubidium atomic clocks built by the same contractor, have experienced similar failures. IRNSS-1H will use modified versions of the same clocks as its predecessors.

IRNSS-1H is a 1,425-kilogram (3142 lb) satellite which is expected to provide ten years of service. It will be stationed in an inclined geosynchronous orbit at longitude of 55 degrees East, where it will replace IRNSS-1A.

The satellite is of the same design as its predecessor, based around ISRO’s I-1K bus, with the same ten-year design life.

Four of the seven satellites in the IRNSS constellation are deployed in inclined orbits, with two each at 55 and 111.75 degrees East. The remaining three satellites are in equatorial geostationary orbits, at 34, 83 and 129.5 degrees East.

Deployment of IRNSS began in July 2013, with the launch of IRNSS-1A, while the April 2016 launch of IRNSS-1G completed the initial constellation. All seven satellites in orbit were launched by ISRO using PSLV-XL vehicles, the same type of rocket that was tasked with delivering IRNSS-1H to orbit on Thursday.

2015-03-28-110556

The Polar Satellite Launch Vehicle, or PSLV, is the workhorse of India’s space program. First flown in September 1993, it has completed thirty-eight successful missions from forty launches prior to Thursday. The rocket’s last thirty-six consecutive launches, spanning almost twenty years, have been successful. This apparent failure would be a rare loss for ISRO in its recent successful era.

PSLV is a four-stage rocket, using a combination of solid and liquid-fuelled stages. In its standard configuration, the PSLV-G, the rocket is augmented at liftoff by six strap-on solid rocket motors, although the lower-capacity PSLV-CA version omits these. The PSLV-XL configuration, first flown in 2008, uses six more powerful strap-ons to achieve a higher payload capacity.

Thursday’s launch used PSLV C39, a PSLV-XL vehicle which will fly from the Second Launch Pad (SLP) at the Satish Dhawan Space Centre on Sriharikota Island. The Satish Dhawan Space Centre, previously named the Sriharikota High Altitude Range (SHAR), has been the point of departure for all of India’s orbital launches.

The Second Launch Pad was built in the early 2000s to support launches of ISRO’s PSLV rocket, as well as the larger Geosynchronous Satellite Launch Vehicle (GSLV), alongside the nearby First Launch Pad (FLP). Unlike the First Launch Pad, where rockets are assembled at the pad, rockets launched from the Second pad are integrated atop a mobile platform in the complex’s Vehicle Assembly Building.

 

PSLV C39’s launch began with ignition of the first stage once Thursday’s countdown reached zero. The first stage, or PS1, uses an S-138 solid rocket motor. The first four PS0M-XL strap-on boosters ignited 0.42 and 0.62 seconds later, as the PSLV began its ascent. The final pair of boosters are air-lit, beginning their burn 25 seconds after liftoff.

Each booster consists of an S-12 solid rocket motor. After burnout, the two pairs of ground-lit boosters separated from the rocket at 69.9 seconds and 70.1 seconds mission elapsed time, while the air-lit boosters separated 92 seconds into the flight.

Burnout and separation of the PSLV’s first stage occurred one minute and 50.26 seconds after liftoff, with the second stage igniting its Vikas engine two tenths of a second later. The second stage, designated PS2 or L-40, is liquid-fuelled and burns UH25 propellant oxidized by dinitrogen tetroxide.

The Vikas engine is a license-built derivative of the French Viking engine, which powered the Ariane 1, 2, 3 and 4 rockets. It burned for about two-and-a-half minutes. The payload fairing – or “heat shield” in ISRO parlance – was to separate from the nose of the rocket 92.8 seconds into the second stage burn – however, this never occurred, pointing to the first issue for the launch.

Four minutes and 23.08 seconds after liftoff, the second stage separated from the vehicle. The PS3 third stage ignited its solid-fuelled S-7 motor 1.2 seconds later, for a burn of about seventy seconds. A coast phase followed third stage burnout. At this point the overlaps on the mission control center showed misalignment, pointing to an issue.

At ten minutes, 6.72 seconds mission elapsed time, the spent third stage was jettisoned. Ten seconds later, fourth stage ignition took place. The PS4, or L-2.5, fourth stage is liquid-fuelled burning monomethylhydrazine (MMH) and mixed oxides of nitrogen (MON). It burned for eight minutes and 31.66 seconds.

Thirty-seven seconds after the fourth stage completed its burn, IRNSS-1H appeared to have separated, as images showed the satellite moving around inside what was an unintentional fairing prison.

The satellite was aiming to be separated into a subsynchronous transfer orbit, with a perigee of 284 kilometers (177 miles, 153 nautical miles), an apogee of 20,650 km (12,831 mi, 11,150 nmi) and 19.2 degrees inclination.

The margin of error for the launch is five kilometers (3.1 miles, 2.7 nautical miles) for the perigee, 675 km (419 mi, 365 nmi) for the apogee and 0.2 degrees for the inclination. IRNSS-1H was to use its onboard propulsion system to maneuver to its final geosynchronous orbit.

Thursday’s launch was the fifth of 2017 for ISRO, and the third of the year for the PSLV, following June’s successful deployment of CartoSat-2E aboard another PSLV-XL. ISRO’s next launch is expected to occur in November, with PSLV-XL C40 delivering IRNSS-1I into orbit. However, the impact on this failure on the schedule is currently unknown.

Quelle: NS

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Top space scientists back ISRO to bring PSLV back to its glory

 
As the heatshield failed to separate from the satellite, ISRO's 8th navigation satellite launch IRNSS-1H was termed as unsuccessful and scientists have undertaken an analysis to study the cause of the incident. PTI Photo

As the heatshield failed to separate from the satellite, ISRO's 8th navigation satellite launch IRNSS-1H was termed as unsuccessful and scientists have undertaken an analysis to study the cause of the incident. PTI Photo

 

 
India's top space scientists backed ISRO to bring PSLV back to its glory but acknowledged that yesterday's failure is a matter of concern and hurting as the rocket had a good track record.

Striking a note of caution against complacency, they urged team ISRO not to lose heart and reposed confidence in the space agency's ability to bounce back.

The PSLV-C39 mission carrying the replacement navigation satellite IRNSS-1H failed yesterday. ISRO said PSLV-C39 had a normal lift-off and all the flight events took place exactly as planned, except heat shield separation.

"This resulted in satellite separation occurring within the heat shield. The satellite is inside the heat shield resulting in the unsuccessful mission. Detailed analysis is in progress to identify the cause of the anomaly in the heat shield separation event", according to ISRO.

Former ISRO Chairman K Kasturirangan said the space agency has gone through unsuccessful missions in the past, particularly in the early phase of the country's space programme.

"Every time we have come back with redoubled vigour and made sure that not only it (failure) does not repeat, the probability of these things happening is minimised," he told PTI.

"But space is certainly a risky endeavour. So, one has to keep an allowance for it. One should not be complacent, do the best and then leave the rest of it to providence because there is a small component of probability that in spite of every thing being done, in what we call as perfect, there can something which can be residual. So, we should not be complacent," Kasturirangan said.

"We had an extraordinary string of successes with PSLV, so it's all the more hurting because of the fact that we expect 100 per cent success every time to we do with PSLV," he said.

Kasturirangan said he has no doubt ISRO would move forward with redoubled vigour and greater determination.

"One satellite was involved and certainly (it's) a setback in that sense but there is no question of looking back; we have to look forward; they (ISRO) have got a big agenda for space and ambitious agenda; it can be fulfilled only with courage of conviction, determination and exceptional technical professionalism. In all these, ISRO is now well known and established its credentials," he said.

Former ISRO Chairman, G Madhavan Nair described the unsuccessful mission as "very unfortunate".

"PSLV had a good track record. About 40 launches it has done. Now, a failure like this is difficult to digest," he said.

But Nair noted: "Failures are not uncommon. If you look at the global scenario, five to ten per cent is a failure rate of proven launch vehicles itself. Compared to that, we were hardly one failure in 40. That's our record. It has become two (failures out of 40 launches). We cannot be satisfied with statistics. We have to be concerned about it."

"I am sure ISRO team will be able to find why and how it (the failure) has happened, and fix it, and come back to launch pad as quickly as possible. That's been ISRO culture. My message to ISRO team, they should not lose heart, go hard into failure reason and fix it," he told PTI.

Another former ISRO Chairman K Radhakrishnan tweeted: "Team@ ISRO, Don't get disheartened with the outcome of PSLV-C39. Intrinsic resilience will bring PSLV back to its glory soon. Move ahead boldly".

PSLV had a record of 39 consecutive successful launches ever since its maiden flight failed more than two decades ago.
Quelle: DECCAN HERALD
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ISRO launch ‘unsuccessful’: What is heat shield and why was IRNSS-1H satellite not released?

The ISRO chairman described the mission as a “mishap” after announcing that the IRNSS-1H satellite was not released by the rocket. 

 
ISRO’s 8th navigation satellite launch IRNSS-1H was termed ‘unsuccessful’.
ISRO’s 8th navigation satellite launch IRNSS-1H was termed ‘unsuccessful’.(PTI Photo)

India’s mission to place a navigation satellite into space failed on Thursday after the spacecraft carrying it suffered a technical fault on the final leg after a perfect launch.

Indian Space Research Agency (ISRO) chairman Kiran Kumar described the mission as a “mishap” shortly after announcing that the IRNSS-1H satellite was not released by the PSLV-39 rocket as the heat shield didn’t separate from the spacecraft.

Thursday’s setback is considered a rare failure in India’s space mission involving the PSLV, dubbed as ISRO’s ‘workhorse’, which has had a time-tested record of 39 consecutive successful launches. Before this, its maiden flight failed 24 years ago.

What is a heat shield? 

A heat shield is an encasement which protects the satellite in the rocket from ultra-high temperatures, acoustic pressures that the spacecraft experiences while travelling in the Earth’s atmosphere, an article in the Indian Express said.

In space shuttles, the heat shield must protect the crew capsule and its precious astronaut crew from temperatures that can melt metal. These ultra-high temperatures result from friction between the air and the speeding spacecraft, according to Nasa. 

Heat shield separation and satellite

Pressures decrease once the spacecraft is outside Earth’s atmosphere, allowing the heat shield to separate in the fourth phase of the launch. 

 
 

After the heat shield failed to separate, the IRNSS-1H satellite could not be released into the orbit. 

The eighth satellite was a replacement for IRNSS-1A, one of the seven satellites in India’s navigation satellite constellation, as its three rubidium atomic clocks on board had stopped functioning. It was also the first time the private sector was actively involved in assembling and testing of a satellite. 

ISRO said it will probe why the shield didn’t peel off.

Quelle: HindustanTimes


Tags: PSLV launch of navigation satellite fails Raumfahrt - Startvorbereitung für ISRO´s PSLV-C39 mit IRNSS-1H Satelliten 

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Samstag, 2. September 2017 - 20:05 Uhr

Astronomie - Armageddon: scientists calculate how stars can nudge comets to strike Earth

2.09.2017

Armageddon: scientists calculate how stars can nudge comets to strike Earth

Plotting how often stars stray into the Oort cloud allows astronomers to assess the risk of all life being wiped out by a cosmic cataclysm 

 
 
A new research paper predicts between 19 and 24 stars will come sufficiently close to deflect comets from their original paths.
 A new research paper predicts between 19 and 24 stars will come sufficiently close to deflect comets from their original paths in the next 1m years. Photograph: Mopic / Alamy/Alamy

The collision of a giant comet with the Earth is one of the most violent and cataclysmic events that could befall our planet. It has happened in the past, but the odds of another such catastrophe have remained uncertain.

Now astronomers have performed the cosmic equivalent of a risk assessment. A new paper calculates how often stars stray into the Oort cloud, a vast, spherical shell of billions of icy objects that is thought to envelop our solar system. Such close encounters can dislodge these loosely orbiting comets, sending them hurtling into the solar system, risking a collision course with the Earth.

Within the next million years, the paper predicts, between 19 and 24 stars will come within 3.26 light years of the sun – sufficiently close to deflect comets markedly from their original paths. 

“Certainly anything coming within that distance you should worry about,” said Coryn Bailer-Jones, of the Max Planck Institute for Astronomy in Heidelberg and the paper’s author.

Not all close encounters would lead to comets hitting the Earth – this would depend on a mixture of luck and on where the Earth is in its orbit relative to the passing star – but the chances of a collision would peak at these time points.

oort

A further 490 to 600 stars will pass the sun within a distance of 16.3 light years within the next million years, the paper estimates. This is far beyond the predicted outer reaches of the Oort cloud, but in the case of a very large star, still potentially close enough to cause comets to swerve in their tracks.

 

 

The Oort cloud has never been observed directly, but scientists have inferred its existence because the comets we see in the night sky would have disintegrated or sublimed long ago if they had always been in their current orbits. So scientists believe they must spend most of their existence in an outer reservoir and get kicked inwards by passing stars.

Theoretical models suggest the Oort cloud spans from as close as 2,000 astronomical units (1AU is the Earth-sun distance) to as far as 200,000 AU. There are likely to be billions of loosely orbiting comets, with sizes up to a few or even a few dozen kilometres. Given their great distance, these comets feel only a very slight pull of the sun’s gravity – just enough to keep them in orbit – and can be easily dislodged.

The latest calculations are based on data from the Gaia space telescope, which is mapping the positions and trajectories of about 1% of the Milky Way’s 200 to 300 billion stars.

Within the Milky Way’s disk, stars are orbiting about the galactic centre. Our sun completes one orbit in about 250m years, sometimes crossing the paths of other stars in brief stellar encounters.

The latest finding, published in the journal Astronomy & Astrophysics, suggests that these encounters occur about twice as frequently as previous estimates.

The Barringer crater, caused by a meteor, near Winslow in Arizona, US.
Pinterest
 The Barringer crater, caused by a meteor, near Winslow in Arizona, US. Photograph: Alamy Stock Photo

Previously, Gaia scientists revealed that the closest encounter on the horizon will be a dwarf star, Gleise 710, which will come within 16,000 AU in about 1.3m years. “Gaia found it’s going to come much closer than we thought. It’s quite exciting,” said Bailer-Jones. “But we’re going to have to wait more than a million years I’m afraid.”

In the future, astronomers are hoping to extend their search deep into the past in the hope of finding stars that might be ultimately responsible for the demise of the dinosaurs, 66m years ago.

Although it is not certain whether the impact that is thought to have caused this mass extinction was a comet or an asteroid, some speculate that a comet is more likely as these tend to be bigger and so more likely to have caused the most cataclysmic impacts.

“Potentially you could imagine tracing the orbit back 66 million years and identifying whether there was any star that came close to the sun and postulating whether that ejected a comet,” said Bailer-Jones. “That would be the holy grail.”

Quelle: theguardian


Tags: Astronomie - Armageddon: scientists calculate how stars can nudge comets to strike Earth 

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Donnerstag, 31. August 2017 - 21:30 Uhr

Raumfahrt - SpaceX bekommt OK für Landezone auf Space Coast

31.08.2017

SpaceX gets OK for landing zone on Space Coast

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Private commercial rocket company SpaceX got approval for additional space for its Dragon spacecraft and Falcon Heavy rocket at Cape Canaveral.

The Hawthorne, Calif.-based company got the OK on Aug. 21 to build a stormwater system at Landing Zone 1, formerly known as Launch Complex 13. Price Civil Design LLC is the civil engineer team behind the project.

Sources say SpaceX is building a temporary Dragon processing facility at Cape Canaveral until a long-term Dragon processing and refurbishment operations can be established at a location yet to be determined. The landing zone also will be a key location for SpaceX's Falcon Heavy — its largest rocket, which is equipped with three boosters. The company plans to build two more landing pads to land two rocket boosters simultaneously and one on a drone ship in the sea.

Orlando Business Journal first reported in January about the SpaceX landing pads. SpaceX signed a five-year deal for launch complex 13 to land rockets in 2015, however, the complex was equipped with only one landing pad.

Located on two patches of land — each a little more than 11 acres, according to Cape Canaveral Air Force Station — SpaceX hopes to have the additional pads ready by November when it launches its Falcon Heavy.

The new pads would need to be built in a way to handle the force of the returning boosters. Each concrete pad would cover more than 11 acres, with an approximate diameter of 282 feet surrounded by an area of 50-foot-wide, hard-packed soil. The pads would be 18 inches thick and designed to support the weight and thrust of the Falcon booster vehicle, according to documents.

While SpaceX does not have its main manufacturing facility in Central Florida, the company does launches at least twice a month and has a refurbishment center in Port Canaveral — all activity that supports dozens, if not hundreds of jobs locally. Right now, the company has nearly 20 job openings posted on its website.

Quelle: Orlando Business Journal


Tags: Raumfahrt - SpaceX bekommt OK für Landezone auf Space Coast 

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Donnerstag, 31. August 2017 - 07:30 Uhr

Astronomie - Wir haben gerade 15 neue geheimnisvolle kosmische Radio-Bursts aus dem Weltraum gesehen

31.08.2017

We’ve just seen 15 new mysterious cosmic radio bursts from space

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Scouring the skies for alien technology has turned up strange radio bursts

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One of the most mysterious objects in space just got even weirder. A group of researchers just found 15 new fast radio bursts, all from the only one of these objects that we’ve ever seen repeat.

Fast radio bursts (FRBs) are some of the universe’s strangest phenomena: powerful radio signals that flash from distant space for milliseconds and then disappear. They have been attributed to everything from black holes to extraterrestrial intelligence.

Because they’re so brief, and because radio telescopes can only watch a small area of the sky at a time, only about 2 dozen FRBs have ever been detected. Of those, only one has been observed to repeat: FRB 121102, which resides in a dwarf galaxy about 3 billion light years away from Earth.

Now, researchers with the Breakthrough Listen initiative, a $100 billion search for signs of intelligent life in the universe, have detected 15 more pulses from FRB 121102.

These signals were at higher frequencies than any FRB we’ve seen before. It’s still unclear what that means for these elusive events, but researchers hope that it will help narrow down the field of potential explanations.

“Previously we thought there wasn’t much emission at high or low frequencies, but now it looks like there is,” says Avi Loeb at Harvard University. “It’s twice as high as the typical frequency that was previously claimed for this repeater.”

A higher range of frequencies could make repeating FRBs like 121102 easier to detect, which is crucial because all of the current attempts to explain them have only one source to work from. But it also adds another layer of weirdness which could make the mechanism producing FRBs even more difficult to pin down.

“It’s very funky how the individual bursts can pop up anywhere in this wide range of frequencies, even though each individual burst has a relatively narrow frequency coverage,” says Peter Williams, also at Harvard University. “I have yet to see anyone offer up a good explanation for how that might happen.”

Quelle: NewScientist


Tags: Astronomie - Wir haben gerade 15 neue geheimnisvolle kosmische Radio-Bursts aus dem Weltraum gesehen 

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Mittwoch, 30. August 2017 - 21:00 Uhr

Raumfahrt - NASA´s LRO sieht Sonnenfinsternis von Mond aus

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NASA’s Lunar Mission Captures Solar Eclipse as Seen From the Moon

During the total solar eclipse on Aug. 21, NASA’s Lunar Reconnaissance Orbiter, or LRO, captured an image of the Moon’s shadow over a large region of the United States, centered just north of Nashville, Tennessee.

 

As LRO crossed the lunar south pole heading north at 3,579 mph (1,600 meters per second), the shadow of the Moon was racing across the United States at 1,500 mph (670 meters per second).

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NASA’s Lunar Reconnaissance Orbiter shows the shadow of the Moon cast on the United States during the Aug. 21, 2017, total solar eclipse.
Credits: NASA/GSFC/Arizona State University

A few minutes later, LRO began a slow 180-degree turn to look back at Earth, capturing an image of the eclipse very near the location where totality lasted the longest. The spacecraft’s Narrow Angle Camera began scanning Earth at 2:25:30 p.m. EDT (18:25:30 UTC) and completed the image 18 seconds later.

 

animated image of eclipse changes exposure/annotations
This animation begins with the black-and-white image of the Moon’s shadow on Earth, as seen by NASA’s Lunar Reconnaissance Orbiter, or LRO. The levels of gray in the image are gradually adjusted, saturating the background until the features of the landscape disappear. At that point, it’s possible to see the edge of the total solar eclipse. As the gray levels are restored, the umbra, or the completely shadowed area, becomes visible, followed by the penumbra, or partial shadow where part of the Sun peaks over the edge of the Moon.LRO’s Narrow Angle Camera can record 3600 gray levels, whereas most digital cameras record only 255 levels of gray. The camera was designed this way because the Moon is a high-contrast target, with very bright materials next to dark materials. In these images, those 3,600 levels of gray were squeezed into 255 levels because that’s what a typical computer screen is capable of displaying.
Credits: NASA/GSFC/Arizona State University

The Narrow Angle Camera is part of the Lunar Reconnaissance Orbiter Camera system. Two Narrow Angle Cameras capture high-resolution black and white images, and a third, the Wide Angle Camera, captures moderate-resolution images using filters to provide information about the properties and color of the lunar surface. 

 

The Narrow Angle Camera builds up an image line by line rather than the more typical “instantaneous” framing that occurs with digital or cell-phone cameras. Each line of the image is exposed for less than one-thousandth of a second; the exposure time was set as low as possible to prevent bright clouds from saturating the sensor. It takes about 18 seconds to acquire all 52,224 lines for the image.

 

While the thrill of the total eclipse was in experiencing the shadow of the Moon sweep across us on Earth, on the Moon this was just another day. The lunar nearside was one week into its two-week night, while the Sun shone on the far side in the middle of its two-week day. Because solar eclipses do not affect the health or power supply of the spacecraft, LRO operated normally during the total solar eclipse.

 

Launched on June 18, 2009, LRO has collected a treasure trove of data with its seven powerful instruments, making an invaluable contribution to our knowledge about the Moon and reminding us, through these eclipse images, of the beauty of our Earth.  

 

LRO is managed by NASA's Goddard Space Flight Center in Greenbelt, Maryland, as a project under NASA's Discovery Program. The Discovery Program is managed by NASA's Marshall Spaceflight Center in Huntsville, Alabama, for the Science Mission Directorate at NASA Headquarters in Washington.

 

The Lunar Reconnaissance Orbiter Camera was developed at Malin Space Science Systems in San Diego, California and Arizona State University.

Quelle: NASA


Tags: Raumfahrt - NASA´s LRO sieht Sonnenfinsternis von Mond aus 

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