пятница, 11 октября 2019 г.

Tourmaline | #Geology #GeologyPage #Minerals Locality:…

Tourmaline | #Geology #GeologyPage #Minerals

Locality: Pederneira Mine, Minas Gerais, Brazil

Size: 5.1 × 1.7 × 1.2 cm

Photo Copyright © Viamineralia /e-rocks. com

Geology Page

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River relic spied by Mars Express

ESA — Mars Express Mission patch.

10 October 2019

Mars may seem to be an alien world, but many of its features look eerily familiar – such as this ancient, dried-up river system that stretches out for nearly 700 kilometres across the surface, making it one of the longest valley networks on the planet.

Plan view of Nirgal Vallis

The area of Mars shown in these new images from ESA’s Mars Express spacecraft lies just south of the planet’s equator, and is known to have been shaped by a mix of flowing water and impacts: events where rocks sped inwards from space to collide with the martian surface.

Both of these mechanisms are visible here: a number of impact craters, some large and some small, can be seen speckled across the ochre, caramel-hued surface, and a tree-like, forked channel cuts prominently through the centre of the frame.

Nirgal Vallis in context

This ancient valley system is named Nirgal Vallis, and was once filled with running water that spread across Mars. By exploring the characteristics of the surrounding craters, scientists estimate the system’s age to be between 3.5 and 4 billion years old.

Topographic view of Nirgal Vallis

The part of Nirgal Vallis captured in these images lies towards the western end of the river system, where it is slowly spreading out and dissipating; the eastern end is far less branched and more clearly defined as a single valley, and opens out into the large Uzboi Vallis – the suspected location of a large, ancient lake that has long since dried up.

Nirgal Vallis is a typical example of a feature known as an amphitheatre-headed valley. As the name suggests, rather than ending bluntly or sharply, the ends of these tributaries have the characteristic semi-circular, rounded shape of an Ancient Greek amphitheatre. Such valleys also typically have steep walls, smooth floors, and, if sliced through at a cross-section, adopt a ‘U’ shape. The valleys pictured here are about 200 m deep and 2 km wide, and their floors are covered in sandy dunes; the appearance of these dunes indicates that martian winds tend to blow roughly parallel to the valley walls. 

Perspective view of Nirgal Vallis

We see valleys like this often on Earth, including valleys found in the Chilean Atacama Desert, the Colorado Plateau, and on the islands of Hawaii. Mars also hosts a few of them, with Nanedi Valles and Echus Chasma joining Nirgal Vallis as clear examples of this intriguing feature. Both of these features also resemble terrestrial drainage systems, where meandering, steep-sided valleys – thought to have been formed by free-flowing water – have carved their way through hundreds of kilometres of martian rock, forging through old volcanic plains, lava flows, and material deposited by strong martian winds over time.

Valleys such as Nirgal Vallis are ubiquitous in the low-latitude regions surrounding the martian equator, indicating that these areas once experienced a far milder and more Earth-like climate. Despite the arid, hostile world we see today, Mars is thought to have once been a far warmer and wetter planet – and we see signs of this in the diverse mix of features and minerals found across its surface.

Mars Express

Scientists believe that Nirgal Vallis formed in a similar way to morphologically similar valleys we see on Earth. As there appear to be no branching, tree-like tributaries feeding into the main valley of Nirgal Vallis, it is likely that water was replenished on ancient Mars by a mix of precipitation and overland flow from the surrounding terrain.

The system may also have its roots in a process known as groundwater sapping: when water struggles to travel vertically through a medium, and so instead continually seeps laterally through material in layers beneath the surface. We see this kind of mechanism on Earth in environments where surface material is very fine and loose and thus difficult for water to penetrate – largely silty, sandy, unconsolidated, and fine-grained environments, where lower layers of the surface are permeable and friendlier to water than those above.

Nirgal Vallis in 3D

The spacecraft captured these observations using its High Resolution Stereo Camera, an instrument that is mapping the whole surface Mars in full colour and at high resolution. Its aim – of characterising and understanding the Red Planet in its entirety – will be supported and continued by the ESA-Roscosmos ExoMars Trace Gas Orbiter, which arrived at Mars in 2016, and the ExoMars Rosalind Franklin rover and its accompanying surface science platform, which will arrive next year. Together, this ground-breaking fleet will help unlock the mysteries of Mars.

Related links:

Mars Express: http://www.esa.int/Our_Activities/Space_Science/Mars_Express

High Resolution Stereo Camera: https://m.esa.int/Our_Activities/Space_Science/Mars_Express/Mars_Express_instruments

Trace Gas Orbiter (TGO): http://www.esa.int/Our_Activities/Human_and_Robotic_Exploration/Exploration/ExoMars/First_results_from_the_ExoMars_Trace_Gas_Orbiter

ExoMars Rosalind Franklin rover: http://www.esa.int/Our_Activities/Human_and_Robotic_Exploration/Exploration/ExoMars/ExoMars_2020_rover

Images, Text, Credits:ESA/DLR/FU Berlin, CC BY-SA 3.0 IGO/NASA MGS MOLA Science Team.

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AI challenged to stave off collisions in space

ESA — European Space Agency patch.

10 October 2019

ESA is challenging machine learning experts to help forecast and prevent collisions in space. The Agency’s Advanced Concepts Team and Space Debris Office have come together to set up the latest in a series of AI-themed competitions based on actual space data.

Debris strike

Space is not as empty as it used to be. More than 34 000 items of space debris bigger than 10 cm are orbiting our planet. Of those, some 22 300 items are being regularly tracked by the telescopes and powerful radars of the US Space Surveillance Network and their trajectories maintained in a catalogue.

In highly-trafficked orbits, active collision avoidance has become a routine task in space operations. Space surveillance data reveal potential risks for satellites to collide with another space object at multiple kilometres per second – whether from active missions or space debris.

For a typical satellite in low-Earth orbit, hundreds of alerts are issued weekly, in the form of ‘conjunction data messages’. After automatic processing and filtering most of these are found to be low-risk, but that still leaves about two actionable alerts per mission per week, requiring detailed examination by a human analyst.

On average, ESA needs to perform more than one collision avoidance manoeuvre per satellite per year, the vast majority due to space debris.

Predicted conjunction

ESA’s Space Debris Office at the European Space Operations Centre in Darmstadt, Germany, supports collision avoidance activities for the low-Earth-orbiting Aeolus wind-mapping mission, the Cryosat-2 ice mapper and the triple-satellite Swarm constellation, monitoring Earth’s magnetic field.

Their remit also extends to the four-satellite Cluster constellation – probing the magnetic field and its interaction with the solar wind – which is in an eccentric orbit climbing to the geostationary region, as well as more than a dozen missions from partner agencies or commercial operators.

Klaus Merz of the Space Debris Office explains: “The conjunction data messages that highlight these close approaches contain various details such as the identity of the satellite and potential collider, the time of closest approach, minimum distance and uncertainty. From some of these attributes we compute a collision risk.”

Distribution of space debris around Earth

“In the days following the first message, as the uncertainties shrink, follow-up conjunction data messages are released, refining the knowledge acquired on their close encounter. Typically about three new messages become available daily, and over the course of a week the last obtained message can be assumed to include the best knowledge we have about the potential collision of these two objects.

“However we cannot wait for this last data message before taking action: In most cases the Space Debris Office will alert control teams and start thinking about a potential avoidance manoeuvre three days before the closest approach, then make a final decision one day before, based on a threshold of a one in a ten thousand risk of collision.

Spatial density of objects by orbital altitude

“In this challenge we ask competitors to build a model that makes use of the conjunction data messages recorded up to two days prior to the closest approach in order to predict the final risk, contained in the last available message before the approach.”

The Space Debris Office are releasing the last six years of conjunction data messages, with some of the later-stage messages kept hidden, for the competitors asked to predict their end state instead.

“The messages form a time series, so you can see how the risk evolves over time, as the uncertainties on satellite positions and observational errors shrink,” explains Dario Izzo of the Advanced Concepts Team.

“The challenge for machine learning is that the great majority of these conjunction data messages do not actually result in a significant collision risk, so this will be a matter of learning from a few relatively rare events. Out of a very large database, they will be learning only from the tail of the distribution, which makes it more difficult.”

Space debris team at ESOC

This space collision avoidance challenge will be formally launched on Wednesday 16 October, and last for two months. Competing teams will be able to download the Space Debris Office conjunction data message database, provided with the kind permission of the Space Surveillance Network.

The competition is of more than purely academic interest, because the Space Debris Office is planning to develop technologies to further automate the collision avoidance process as part of ESA’s new Space Safety Programme, put forward for approval at November’s Space19+ Ministerial.

This development driven by the predicted growth in low-orbiting satellites and the coming wave of mega-constellations for which detailed case-by-case analysis of every high risk close approach event by human analysts will not be a not a viable option – nor will the actual preparation and execution of avoidance manoeuvres.

Related links:

Space collision avoidance challenge: https://kelvins.esa.int/collision-avoidance-challenge/

Space19+: http://blogs.esa.int/space19plus/

Advanced Concepts Team (ACT): http://www.esa.int/act

Space debris: http://www.esa.int/Our_Activities/Space_Safety/Space_Debris

Kelvins competitions website: https://kelvins.esa.int/

Animations, Images, Text, Credits:ESA, CC BY-SA 3.0 IGO.

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Alexei Leonov, the first spacewalker is dead

Rest In Peace.

Oct. 11, 2019

Alexei Leonov, released in space in 1965, died on Friday at the age of 85.

Cosmonaut Alexei Leonov, the first spacewalker

Soviet cosmonaut Alexei Leonov died Friday at the age of 85. He was the first man to make a spacewalk in 1965 and, ten years later, commanded the first joint space mission of the USSR and the United States.

On March 19, 1965, Alexei Leonov made his first outing from his ship Voskhod-2 in the open space, earning him the nickname of first «pedestrian of space». He had cautiously departed two to three meters from the ship, finding the operation very painful.

First spacewalk, Alexey Leonov, March 18, 1965

Blinded by the Sun, despite his golden visor, he was held securely by a cable at the airlock of his ship. «Here, I try,» he said, leaving. The operation lasted twenty minutes, twelve minutes entirely outside the Voskhod.

Long illness

The cosmonaut was also the Soviet side commander of the Apollo-Soyuz mission in 1975, the first joint between the two rivals of the Cold War and the space race. This mission marked the beginning of a technological cooperation that continues today.

The cosmonaut was also a close friend of his compatriot Yuri Gagarin, the first man in space. When he died in a plane crash on March 27, 1968 near Moscow, he was one of the first on the scene.

Alexei Leonov died «after a long illness,» his collaborator Natalia Filimonova told AFP. His funeral is scheduled for Tuesday in Moscow, announced the Cosmonaut Preparation Center.

Alexey Leonov — Wikipedia: https://en.wikipedia.org/wiki/Alexei_Leonov

Image, Video, Text, Credits: ROSCOSMOS/AFP/Orbiter.ch Aerospace/Roland Berga.

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Prehistoric Funerary Ornaments, Kelvingrove Museum, Glasgow, 29.9.19.

Prehistoric Funerary Ornaments, Kelvingrove Museum, Glasgow, 29.9.19.

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ILS — Proton-M launches EUTELSAT 5 West B & MEV-1

ILS — Proton-M / EUTELSAT 5 West B & MEV-1 poster.

Oct. 11, 2019

Proton-M carrying EUTELSAT 5 West B & MEV-1 lift off

An International Launch Services (ILS) Proton-M launch vehicle, with a Briz-M upper stage (Breeze M), launched the EUTELSAT 5 West B communications satellite and Mission Extension Vehicle-1 (MEV-1) from the Baikonur Cosmodrome in Kazakhstan, on 9 October 2019, at 10:17 UTC (16:17 local time). EUTELSAT 5 West B (2864 kg)  is a Ku-band satellite to be located at 5° West.

Proton-M launches EUTELSAT 5 West B & MEV-1

Build by Northrop Grumman, MEV-1 (2326 kg) will provide satellite life-extension service by docking to the client’s vehicles in geosynchronous orbit to provide attitude and orbit control. MEV-1 will extend the life of the Intelsat 901 satellite for five years.

Eutelsat 5 West B

Both spacecraft are built by Northrop Grumman Innovation Systems, formerly known as Orbital ATK. Eutelsat 5 West B will join Eutelsat’s communications fleet in geostationary orbit, replacing the Eutelsat 5 West A spacecraft providing digital and television services primarily in the French, Italian and Algerian markets.


The MEV 1 spacecraft is the first in a series of satellite servicing vehicles for SpaceLogistics, a subsidiary of Northrop Grumman Innovation Systems. MEV 1 will dock with the Intelsat 901 communications satellite and provide propulsion and attitude control functions to extend the spacecraft’s mission.

Related links:

International Launch Services (ILS): http://www.ilslaunch.com/

Eutelsat: https://www.eutelsat.com/en/home.html

Images, Video, Text, Credits: ILS/SciNews/Orbiter.ch Aerospace/Roland Berga.

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An American astronaut decorated by Vladimir Putin

Order of  Lenin medal.

Oct. 11, 2019

Rescued from the Soyuz rocket accident in October 2018, astronaut Nick Hague has received from the Russian president a prestigious distinction for his courage.

Soyuz MS-10 launch failure

Russian President Vladimir Putin has awarded the Order of Courage, one of the highest honors of the country, to an American astronaut. He had survived a year ago the failed takeoff of a Soyuz rocket.

According to a presidential decree published on Tuesday, the American Nick Hague, 44, is rewarded for «his courage and his high degree of professionalism» in perilous conditions during the launch at the Russian cosmodrome of Baikonur, located in Kazakhstan.

On October 11, 2018, the «Soyuz» rocket in which Nick Hague had sailed and the Russian Alexey Ovchinin had disintegrated minutes after taking off for the International Space Station (ISS), an unprecedented accident for the Russian space program since the end of the USSR.

After being successfully ejected by the automatic rescue system, the two men were released unscathed despite the very strong pressure. «It was a quick flight,» commented Alexei Ovchinin, laconic, moments after the start of the incident. According to NASA, «launcher failure» occurred after 119 seconds of travel, while the rocket was launched at over 7500 km / h.

In March, they returned successfully to the ISS, where they returned last week after a six-month mission. It was the first space stay for Nick Hague, and the second for Alexey Ovchinin.

Considered one of the highest Russian distinctions, the Order of Courage is often awarded posthumously.

The International Space Station is one of the latest examples of active cooperation between Russia and the United States in a context of unprecedented tensions since the Cold War.

Related articles:

Crew in Good Condition After Booster Failure

Soyuz MS-10 — Emergency landing after a failure

Images, Video, Text, Credits: ATS / NASA / ROSCOSMOS / SciNews / Orbiter.ch Aerospace / Roland Berga.

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Northrop Grumman Pegasus XL launches ICON

NASA — Ionospheric Connection Explorer (ICON) logo.

11 oct. 2019

L-1011 Stargazer aircraft and Pegasus XL rocket

A Pegasus XL rocket launched NASA’s Ionospheric Connection Explorer (ICON) on 11 October 2019, at 02:00 UTC. The Northrop Grumman L-1011 Stargazer aircraft took off from the Skid Strip runway at Cape Canaveral Air Force Station in Florida. ICON will explore the ionosphere, the dynamic region where Earth meets space.

Pegasus XL launches ICON (Ionospheric Connection Explorer)

ICON will study the ionosphere, a region of Earth’s upper atmosphere where terrestrial weather meets space weather. Disturbances in the ionosphere triggered by solar storms or weather activity in the lower atmosphere can cause disturbances in GPS navigation and radio transmissions.

Ionospheric Connection Explorer (ICON)

The mission’s staging point was changed from Kwajalein Atoll to Cape Canaveral Air Force Station in mid-2018. Delayed from June 15, Nov. 14, and Dec. 8, 2017. Delayed from June 14, Sept. 24, Oct. 6, Oct. 26 and Nov. 3. Scrubbed on Nov. 7. Delayed from 1st Quarter 2019. Delayed from Oct. 9 by poor weather.

NASA’s Ionospheric Connection Explorer (ICON): https://www.nasa.gov/icon

Images, Video, Text, Credits: NASA/Randy Beaudoin/Ben Smegelsky/USAF 30th SCS/Anthony Vauclin/Northrop Grumman/SciNews/Orbiter.ch Aerospace/Roland Berga.

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2019 October 11 Planet Earth at Blue Hour Image Credit &…

2019 October 11

Planet Earth at Blue Hour
Image Credit & Copyright: Matthias Ciprian

Explanation: Nature photographers and other fans of planet Earth always look forward to the blue hour. That’s the transition in twilight, just before sunrise or after sunset, when the Sun is below the horizon but land and sky are still suffused with beautiful bluish hues of light. On August 8 this early morning blue hour panorama scanned along the clear western sky, away from the impending sunrise. A breathtaking scene, it looks down the slopes of Mt. Whitney, from along the John Muir Trail toward rugged peaks of planet Earth’s Sierra Nevada mountain range. Above the horizon a faint pinkish band of back scattered sunlight, the anti-twilight arch or Belt of Venus, borders the falling grey shadow of Earth itself. Subtle bands of light across the clear sky are anti-crepuscular rays, defined by shadows of clouds near the sunward horizon. Actually following parallel lines they seem to converge along the horizon at the point opposite the rising Sun due to perspective.

∞ Source: apod.nasa.gov/apod/ap191011.html

Roman Columns and Decorated Masonry from the Antonine Wall and Environs, The Hunterian...

Roman Columns and Decorated Masonry from the Antonine Wall and Environs, The Hunterian Museum, Glasgow, 29.9.19.

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NASA Smallsats Can Aid Hurricane Forecasts with GPS

NASA — CYGNSS Mission patch.

October 10, 2019

Eight briefcase-size satellites flying in a row may be key to improving forecasts of a hurricane’s wind speed — detecting whether it will make landfall as a Category 1 or a Category 5. NASA’s Cyclone Global Navigation Satellite System (CYGNSS) fleet, launched in 2016, was designed to show whether the same GPS signals your phone uses for navigation can be used to measure winds deep within a hurricane or typhoon. The answer appears to be a resounding yes.

Weather forecasting models have gotten much better at predicting the future track of a hurricane or typhoon, but they haven’t improved at predicting its maximum wind speed, which scientists call intensity. That’s because these tropical giants are steered by outside forces, such as regional winds, but their intensity depends on forces within each storm. And while many satellites can see the external winds, they can’t see through a hurricane’s thick clouds and rain.

CYGNSS Principal Investigator Christopher Ruf of the University of Michigan in Ann Arbor explained: «To predict intensity, you have to measure wind speed right in the middle of the storm and, until CYGNSS, there hasn’t been a way to do it other than flying Hurricane Hunter planes.»

Image above: Illustration of one of the eight CYGNSS satellites in orbit above a hurricane. Image Credit: NASA.

The new CYGNSS data proved to be an excellent match with Hurricane Hunter data collected at the same time during 2017’s hurricanes Maria, Irma and Jose. The eight small satellites — orbiting with only a 12-minute gap between each one — collected more data on each storm than could be gathered during a Hurricane Hunter flight.

How to See Through Rain and Clouds

To see what’s in the atmosphere, many Earth-observing satellites send out electromagnetic signals with wavelengths that are just fractions of an inch long. To these short-wavelength signals, a drop of drizzle, speck of dust or any other airborne particle is an impenetrable obstacle. Even though the wavelengths are longer than these tiny particles, they are close enough in size that signals bounce off particles like a billiard ball colliding with another ball. By «reading» these scattered signals, researchers can discern the shape and location of clouds and other obstacles that the signals ran into.

In other words, short wavelengths let researchers see a storm but not see through it.

CYGNSS, on the other hand, uses GPS signals. Their wavelength is 7.5 inches (19 centimeters) long — far longer than either the short wavelengths most satellite instruments use or any raindrop ever measured. At that wavelength, Ruf said, «You don’t see a raindrop at all. You just go right through it.» That enables CYGNSS to see through a hurricane and measure the winds at the ocean surface.

GPS satellites, operated by the U.S. Air Force, are in a much higher orbit than the CYGNSS fleet. As a GPS satellite flies over a tropical cyclone, its signals pass unimpeded through the storm and bounce off the ocean surface. In their lower orbit, CYGNSS’s downward-looking GPS receivers are able to intercept signals returning upward. Distortions in these bounced signals show how rough the sea is, enabling researchers to calculate the wind speed that caused the roughness.

Turning Signals Into Measurements

CYGNSS’ eight small satellites have worked well since launch, but the mission’s scientists ran into a major hurdle on the path to processing the GPS signals into wind speed data. In designing the mission, scientists assumed that GPS signals are broadcast at constant strength. But when the scientists started to collect data, they found that the signal power from most GPS satellites changes during each orbit and that the degree of change differs from satellite to satellite. These variations threw off the CYGNSS satellites’ measurements of high winds by as much as 11 mph (18 kph).

«We spent a year or more working on the problem, and we finally got it figured out,» Ruf said. «Basically, the Air Force turns the power up when they go over certain parts of the world where bad guys are trying to jam the signals.» Stronger signals are harder to jam.

Once the CYGNSS team understood the issue, they found a workaround. Each CYGNSS satellite carries not only a primary GPS receiver to collect signals bouncing up from Earth’s surface, but also a secondary, smaller receiver for location and tracking. The team reprogrammed the smaller receivers to measure the strength of the broadcast signal arriving from overhead, which gave them the information they needed to correctly process the signals returning from below.

With that problem solved, the researchers could turn to the task of assessing how CYGNSS data would affect hurricane forecasts.

Experimenting with a research version of the same hurricane model that the National Oceanic and Atmospheric Administration (NOAA) uses for forecasts, the scientists added CYGNSS data to reconstructions of two of 2017’s notable storms, hurricanes Harvey and Irma. The addition of CYGNSS data produced more realistic forecasts, not only of the storms’ intensity, but of their tracks and structure. Other studies have shown similar improvements in forecasts of different storms.

An Unexpected Watery Bonus

To Ruf’s surprise, CYGNSS has proven to have an unforeseen application. The CYGNSS team had planned to routinely turn off their receivers when the satellites fly over land, but the team decided to simplify their operations by having the satellites collect data all the time. Two postdoctoral students at NASA’s Jet Propulsion Laboratory in Pasadena, California, decided to look at the data from over land. «It was really luck as much as anything, but it turns out there’s all kinds of nice science you can do with the land data to measure soil moisture and flooding,» Ruf said.

As the former students, Clara Chew (University Corporation for Atmospheric Research in Boulder, Colorado) and Hugo Carreno-Luengo (Barcelona, Spain), have documented the value of the data, NASA has now officially extended the scope of the mission and invited the science team to redefine the mission purposes. There may be other applications waiting to be discovered as the eight small CYGNSS satellites keep watching hidden winds in tropical storms.

Related links:

CYGNSS data produced more realistic forecasts: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019GL082236

CYGNSS: https://www.nasa.gov/cygnss/

Image (mentioned), Text, Credits: NASA/Earth Science News Team, written by Carol Rasmussen/JPL/Esprit Smith.

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Successful Ocean-Monitoring Satellite Mission Ends

NASA & CNES — Jason-2 Mission patch.

October 10, 2019

The Jason-2/Ocean Surface Topography Mission (OSTM), the third in a U.S.-European series of satellite missions designed to measure sea surface height, successfully ended its science mission on Oct. 1. NASA and its mission partners made the decision to end the mission after detecting deterioration in the spacecraft’s power system.

Image above: The Jason-2/OSTM satellite provided insights into ocean currents and sea level rise with tangible benefits to marine forecasting, meteorology and understanding of climate change. These observations are being continued by its successor, Jason-3. Image Credits: NASA/JPL-Caltech.

Jason-2/OSTM, a joint NASA mission with the French space agency Centre National d’Etudes Spatiales (CNES), the National Oceanic and Atmospheric Administration (NOAA), and the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), launched in June 2008. The mission extended the long-term record of sea surface height measurements started by the NASA-CNES TOPEX/Poseidon and Jason-1 missions. Jason-2/OSTM’s 11-year lifetime well exceeded its three-year design life. These measurements are being continued by its successor, Jason-3, launched in 2016.

«Today we celebrate the end of this resoundingly successful international mission,» said Thomas Zurbuchen, associate administrator of the Science Mission Directorate at NASA Headquarters in Washington. «Jason-2/OSTM has provided unique insight into ocean currents and sea level rise with tangible benefits to marine forecasting, meteorology and our understanding of climate change.»

Since its launch, Jason-2/OSTM charted nearly 2 inches (5 centimeters) of global sea level rise, a critical measure of climate change. The mission has also resulted in the distribution of over a million data products and the publication of more than 2,100 science papers.

Image above: Jason-2/OSTM contributed to a long-term record of global sea levels. This image shows areas in the Pacific Ocean where sea levels were lower (blues) or higher (reds) than normal during the first week of January 2018. Image Credits: NASA/JPL-Caltech.

«Jason-2/OSTM was a high point of operational satellite oceanography as the first Jason mission to formally include EUMETSAT and NOAA as partners,» said Steve Volz, assistant administrator of NOAA’s Satellite and Information Service. «During its 11-year run, Jason-2/OSTM helped improve NOAA’s hurricane intensity forecasts and provided important observations of marine winds and waves and in doing so has anchored these essential ocean altimetry observations in NOAA’s operational observing system requirements.»

With the recent degradation of the spacecraft’s power system, mission partners decided to end the mission to decrease risks to other satellites and future altimetry missions, and to comply with French space law. Final decommissioning operations for Jason-2/OSTM are scheduled to be completed by CNES on Oct. 10.

«With the involvement of EUMETSAT and NOAA, Jason-2 brought high precision monitoring of ocean surface topography and mean sea level to operational status,» said Alain Ratier, EUMETSAT’s director general. «Its 11-year lifetime in orbit was rewarding for the four program partners and the ocean and climate user community.»

Image above: Global sea level has shown a steady rise since the early 1990s to present as measured by Jason-2/OSTM and its predecessors and successor from the early 1990s to present day. Image Credits: NASA/JPL-Caltech.

Jason-2/OSTM’s mission might have ended earlier if not for the ingenuity of its mission teams. In July 2017, the degradation of critical onboard components and control systems required that Jason-2/OSTM move from its original science orbit, deplete excess propellant reserves, and be maneuvered into a slightly lower orbit, away from functioning satellites. In close collaboration with the Ocean Surface Topography Science Team, mission partners identified an orbit that would allow for the continuation of the Jason-2/OSTM measurements while still being compatible with orbital-debris mitigation constraints and of scientific benefit.

This new orbit resulted in less frequent observations of the same location on Earth, but overall resolution of the data improved because the ground tracks of the observations were closer together. This improved resolution is extremely useful for marine gravity studies and the mapping of seafloor topography. It also allowed for valuable operational oceanographic and science observations.

«Not only did Jason-2 extend the precise climate record established by TOPEX/Poseidon and continued by Jason-1, it also made invaluable observations for small- to medium-scale ocean studies in its second, interleaved orbit,» said CNES President Jean-Yves Le Gall. «Even when moved to the ‘graveyard’ orbit, Jason-2 continued to make unprecedented new observations of the Earth’s gravity field, with precise measurements right until the end.»

The technological advancements proven on Jason-1, Jason-2/OSTM and Jason-3 will be put to use well into future decades. Following Jason-3 will be two future Sentinel-6/Jason-CS satellites, planned for launch in 2020 and 2025.

For more information about NASA’s Earth science activities, visit: https://www.nasa.gov/earth

Images (mentioned), Text, Credits: NASA/Steve Cole/JPL/Esprit Smith/CNES/Pascale Bresson/Raphaël Sart/NOAA/John Leslie/EUMETSAT/Neil Fletcher.

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Luca powers up for a spacewalk

ESA — Beyond Mission patch.

10 October 2019

European Space Agency (ESA) astronaut Luca Parmitano is preparing to step out into space for his first spacewalk of the Beyond mission.

ESA astronaut Luca Parmitano assists spacewalkers in the Quest airlock

Scheduled for 25 October, he will work with NASA astronaut Jessica Meir to replace nickel hydrogen batteries with newer lithium ion batteries and install battery adapter plates on the Space Station’s Port-6 truss structure.

This is a process fellow ESA astronaut Thomas Pesquet knows well, having replaced batteries on another power channel during his Proxima mission. We asked him to tell us more about the task and how the crew will prepare.

The lead-up

Known to the crew as an EVA (Extravehicular Activity), each spacewalk is planned up to a year in advance.

Thomas Pesquet spacewalk test

On Station, preparation begins around two weeks ahead, with a set of procedures called the “Road to EVA”.

“Preparing for a spacewalk will make up 2-3 hours of your schedule every day during this time,” Thomas explains. “The crew often carry out prep in their personal time as well.” 

The big day

Live coverage of Luca and Jessica’s spacewalk starts on NASA TV at 10:30 GMT (12:30 CEST), but the crew will begin their preparation around 6:00. And there is to be no showering, shaving, or applying deodorant for at least a day in advance, as any remnants of these products could mix with the pure oxygen inside the suit and pose a fire risk

Astronauts wear a liquid cooling garment underneath their spacesuit. This is connected to the water system that keeps them cool, or warm, by circulating water around their body. They also don a medical monitor and put a dosimeter in their pocket to measure radiation before entering the hatch.

EMU spacesuit

Thomas describes the process inside the airlock as “like scuba diving in reverse”, as astronauts breathe in a controlled way to rid their blood of nitrogen and adjust to lower pressure.

A third crew member, known as the Intravehicular (IV) crew member, is also isolated in the airlock, before it goes to vacuum. This person helps the astronauts with their oxygen masks and into their spacesuits, while making sure everything is checked, tethered and ready for a safe and successful sortie.

It is a role Luca will play in the two spacewalks before his, on 15 and 21 October.

Out in space

Before exiting the airlock, Thomas says, extreme focus is the overriding feeling. 

“Everybody’s watching, so many people have been involved in the preparation, and the risks are so much higher when you’re outside the Space Station,” he explains. “The only thing you can’t really prepare for are the day/night cycles.

“During the night, you only have your helmet light, so you can’t really see anything except what you’re working on. And because you’re working in all body orientations, it’s easy to get disoriented. But you know you can always follow your tether back towards the hatch.”

Luca Parmitano training at NASA’s Johnson Space Center

After exiting the airlock, Thomas says one astronaut will prepare the worksite while the other breaks torque on the pre-positioned adapter plates. Each astronaut will then work to install the adapter plates, needed to replace two older batteries with one new one.

The spacewalk on 25 October is the one of five scheduled for October. Even more are expected in November as Luca ventures out again with the complex task of repairing and enhancing dark matter hunter AMS-02 – a structure never designed to be maintained in orbit.

Related links:

Truss structure: https://www.nasa.gov/mission_pages/station/structure/elements/truss-structure

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

Human and Robotic Exploration: http://www.esa.int/Our_Activities/Human_and_Robotic_Exploration

Beyond mission brochure English: http://esamultimedia.esa.int/docs/HRE/Beyond_interactive_EN.pdf

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

Images, Text, Credits: ESA/S. Corvaja/NASA.

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https://t.co/hvL60wwELQ — XissUFOtoday Space (@xufospace) August 3, 2021 Жаждущий ежик наслаждается пресной водой после нескольких дней в о...