Orbital ATK Launch Scrubbed; Next Attempt Nov. 12

NASA / Orbital ATK - CRS OA-8 Mission patch.

November 11, 2017

On Nov. 12 Orbital ATK will launch its Cygnus spacecraft aboard an Antares rocket on a journey to the International Space Station from NASA’s Wallops Flight Facility on Virginia’s Eastern Shore. The five-minute launch window opens at 7:14 a.m. EST. Cygnus is carrying 7,400 pounds of crew supplies, hardware and scientific research equipment.

Image above: The Orbital ATK Antares rocket, with the Cygnus spacecraft aboard, is seen on launch Pad-0A, Saturday, Nov. 11, 2017, at NASA’s Wallops Flight Facility in Virginia. Orbital ATK’s eighth contracted cargo resupply mission with NASA to the International Space Station will deliver approximately 7,400 pounds of science and research, crew supplies and vehicle hardware to the orbital laboratory and its crew. Image Credits: NASA/Bill Ingalls.

Milestones (Approximate Timing)

- 12:50 a.m. EST — live video of the launch pad airs on Wallops’ Ustream
- 6:45 a.m. — live launch commentary airs on NASA TV
- 7:14 a.m. — five-minute launch window opens
- Launch + 3.7 seconds — liftoff
- L+ 3 min., 34 sec. — main engine cutoff (MECO)
- L+ 3 min., 40 sec. — first stage separation
- L+ 4 min., 11 sec. — fairing separtaion
- L+ 4 min., 16 sec. — interstage separtaion
- L+ 4 min., 24 sec. — second stage ignition
- L+ 7 min., 6 sec. — second stage burnout; orbit insertion
- L+ 9 min., 6 sec. — Cygnus  spacecraft separates — 121.3 miles altitude; 16,846 mph

Related links:

Wallops’ Ustream: http://www.ustream.tv/channel/nasa-tv-wallops

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

Antares: https://blogs.nasa.gov/orbital/category/antares/

Cygnus: https://blogs.nasa.gov/orbital/category/cygnus/

Orbital ATK: https://blogs.nasa.gov/orbital/category/orbital-atk/

Image (mentioned), Text, Credits: NASA/Rob Garner.

Greetings, Orbiter.ch

How much does a kilogram weigh?

CERN - European Organization for Nuclear Research logo.

Nov. 10, 2017

The Kilogram doesn’t weigh a kilogram any more. This sad news was announced during a seminar at CERN on Thursday, 26 October by Professor Klaus von Klitzing, who was awarded the 1985 Nobel Prize in Physics for the discovery of the quantised Hall effect. “We are about to witness a revolutionary change in the way the kilogram is defined,” he declared. 

Image above: The National Institute of Standards and Technology (NIST)-4 Kibble balance measured Planck's constant to within 13 parts per billion in 2017, accurate enough to assist with the redefinition of the kilogram. (Image: J. L. Lee/NIST).

Together with six other units – metre, second, ampere, kelvin, mole, and candela – the kilogram, a unit of mass, is part of the International System of Units (SI) that is used as a basis to express every measurable object or phenomenon in nature in numbers. This unit’s current definition is based on a small platinum and iridium cylinder, known as “le grand K”, whose mass is exactly one kilogram. The cylinder was crafted in 1889 and, since then, has been kept safe under three glass bell jars in a high-security vault on the outskirts of Paris. There is one problem: the current standard kilogram is losing weight. About 50 micrograms, at the latest check. Enough to be different from its once-identical copies stored in laboratories around the world.

To solve this weight(y) problem, scientists have been looking for a new definition of the kilogram.

At the quadrennial General Conference on Weights and Measures in 2014, the scientific metrology community formally agreed to redefine the kilogram in terms of the Planck constant (h), a quantum-mechanical quantity relating a particle’s energy to its frequency, and, through Einstein’s equation E = mc2, to its mass. Planck’s constant is one of the fundamental numbers of our universe, a quantity fixed universally in nature, such as the speed of light or the electric charge of a proton.

Planck’s constant will be assigned an exact fixed value based on the best measurements obtained worldwide. The kilogram will be redefined through the relationship between Planck’s constant and mass.

“There’s nothing to be worried about,” says Klaus von Klitzing. “The new kilogram will be defined in such a way that (nearly) nothing will change in our daily life. It won’t make the kilogram more precise either, it will just make it more stable and more universal.”

However, the redefinition process is not that simple. The International Committee for Weights and Measures, the governing body responsible for ensuring international agreement on measurements, has imposed strict requirements on the procedure to follow: three independent experiments measuring the Planck constant must agree on the derived value of the kilogram with uncertainties below 50 parts per billion, and at least one must achieve an uncertainty below 20 parts per billion. Fifty parts per billion in this case equals approximately 50 micrograms – about the weight of an eyelash.

Image above: Replica of the national prototype kilogram standard no. K20 kept by the US government National Institute of Standards and Technology (NIST), Bethesda, Maryland. (Image: National Institute of Standards and Technology).

Two types of experiment have proved able to link the Planck constant to mass with such extraordinary precision. One method, led by an international team known as the Avogadro Project, entails counting the atoms in a silicon-28 sphere that weighs the same as the reference kilogram. The second method involves a sort of scale known as a watt (or Kibble) balance. Here, electromagnetic forces are counterbalanced by a test mass calibrated according to the reference kilogram.

And that’s where the important discovery made by Klaus von Klitzing in 1980, which earned him the Nobel Prize in Physics, comes into play. In order to get extremely precise measurements of the current and voltage making up the electromagnetic forces in the watt balance, scientists use two different quantum-electrical universal constants. One of these is the von Klitzing constant, which is known with extreme precision, and can in turn be defined in terms of the Planck constant and the charge of the electron. The von Klitzing constant describes how resistance is quantised in a phenomenon called the “quantum Hall effect”, a quantum-mechanical phenomenon observed when electrons are confined in an extra-thin metallic layer subjected to low temperatures and strong magnetic fields.

“This is truly a big revolution,” von Klitzing says. “In fact, it has been dubbed the biggest revolution in metrology since the French Revolution, when the first global system of units was introduced by the French Academy of Sciences.”

CERN is playing its part in this revolution. The Laboratory participated in a metrology project launched by the Swiss Metrology Office (METAS) to build a watt balance, which will be used to disseminate the definition of the new kilogram through extremely precise measurements of the Planck constant. CERN provided a crucial element of the watt balance: the magnetic circuit, which is needed to generate the electromagnetic forces balanced by the test mass. The magnet needs to be extremely stable during the measurement and provide a very homogenous magnetic field.

Note:

CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.

Related link:

Taking the measure of the kilogram: http://home.cern/about/updates/2012/04/taking-measure-kilogram

For more information about European Organization for Nuclear Research (CERN), Visit: http://home.cern/

Images (mentioned), Text, Credits: CERN/Stefania Pandolfi.

Greetings, Orbiter.ch

NASA Moves Up Critical Crew Safety Launch Abort Test

NASA - Space Launch System (SLS) logo / NASA- Orion Multi-Purpose Crew Vehicle patch.

Nov. 10, 2017

Image above: NASA will test Orion’s launch abort system in high-stress ascent conditions during an April 2019 test called Ascent Abort-2. Image Credit: NASA.

NASA’s Orion spacecraft is scheduled to undergo a design test in April 2019 of the capsule’s launch abort system (LAS), which is a rocket-powered tower on top of the crew module built to very quickly get astronauts safely away from their launch vehicle if there is a problem during ascent.

This full-stress test of the LAS, called Ascent Abort Test 2 (AA-2), will see a booster, provided by Orbital ATK, launch from Cape Canaveral Air Force Station in Florida, carrying a fully functional LAS and a 22,000 pound Orion test vehicle to an altitude of 32,000 feet at Mach 1.3 (over 1,000 miles an hour).  At that point, the LAS’ powerful reverse-flow abort motor will fire, carrying the Orion test vehicle away from the missile. Timing is crucial as the abort events must match the abort timing requirements of the Orion spacecraft to the millisecond in order for the flight test data to be valid.

NASA is accelerating the timeline of the test to provide engineers with critical abort test data sooner to help validate computer models of the spacecraft’s LAS performance and system functions.

“This will be the only time we test a fully active launch abort system during ascent before we fly crew, so verifying that it works as predicted, in the event of an emergency, is a critical step before we put astronauts on board,” said Don Reed, manager of the Orion Program’s Flight Test Management Office at NASA’s Johnson Space Center in Houston. “No matter what approach you take, having to move a 22,000-pound spacecraft away quickly from a catastrophic event, like a potential rocket failure, is extremely challenging.”

The test will verify the LAS can steer the crew module and astronauts inside to safety in the event of an issue with a Space Launch System rocket when the spacecraft is under the highest aerodynamic loads it will experience during a rapid climb into or beyond orbit for deep-space missions.

NASA’s Ascent Abort-2 Test of Orion

Video above: In a test targeted for April 2019 known as Ascent Abort-2, NASA will verify the Orion spacecraft’s launch abort system. The test will last less than three minutes with the test crew module reaching an average speed of Mach 1.5, roughly 1020 miles per hour, at approximately 32,000 feet in altitude. Video Credit: NASA.

The LAS is divided into two parts: the fairing assembly, which is a shell composed of a lightweight composite material that protects the capsule from the heat, wind and acoustics of the launch, ascent, and abort environments; and the launch abort tower, which includes the system’s three motors. In an emergency, those three motors – the launch abort, attitude control, and jettison motors –  would work together to pull Orion away from a problem on the launch pad or during SLS first stage ascent, steering and re-orienting for LAS jettison, and pulling the LAS away from the crew module. During a normal launch, only the LAS jettison motor would fire, once Orion and the Space Launch System clear most of the atmosphere, to clear the LAS from Orion and allow the spacecraft to continue with its mission.

Engineers at several NASA centers already are building the Orion test article that has many of the design features and the same mass as the capsule that will carry crew. Because the test is designed to evaluate Orion’s launch abort capabilities, the crew module used for AA-2 will not deploy parachutes after the abort system is jettisoned, nor will it have a reaction control system with thrusters needed to help orient the capsule for a parachute-assisted descent and splashdown after the LAS is jettisoned.

The AA-2 test development and execution is a partnership between Orion Program and the Advanced Exploration Systems Division, the technology advancement organization in the Human Exploration and Operations Mission Directorate at NASA Headquarters in Washington.

NASA Johnson is responsible for producing the fully assembled and integrated crew module and separation ring, including development of unique avionics, power, software and data collection subsystems and several elements of ground support equipment.

The agency’s Langley Research Center in Hampton, Virginia, will build the primary structure of the crew module test article and a separation ring that connects the test capsule to the booster and provides space and volume for separation mechanisms and instrumentation.

Critical sensors and instruments used to gather data during the test will be provided by NASA’s Armstrong Flight Research Center in Edwards, California. The integrated test article will be delivered to NASA’s Kennedy Space Center in Florida, where it will be processed before launch.

NASA’s prime contractor, Lockheed Martin, is providing the fully functional Orion LAS, and the crew module to service module umbilical and flight design retention and release mechanisms.

In 2010, an earlier version of Orion’s LAS was tested to evaluate the performance of the system in during Abort Test Booster-1 at the White Sands Missile Range in New Mexico. For Exploration Mission-1, NASA’s first integrated flight test of Orion atop the powerful SLS -- the abort system will not be fully active since astronauts will not be inside the spacecraft. NASA is working toward a December 2019 launch for EM-1.

Related links:

NASA’s first integrated flight test of Orion atop the powerful SLS: https://www.nasa.gov/feature/the-ins-and-outs-of-nasa-s-first-launch-of-sls-and-orion

December 2019 launch for EM-1: http://orbiterchspacenews.blogspot.ch/2017/11/nasa-completes-review-of-first-sls.html

Space Launch System (SLS): http://www.nasa.gov/sls

Orion Spacecraft: https://www.nasa.gov/exploration/systems/orion/index.html

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

Greetings, Orbiter.ch

Dawn Explores Ceres' Interior Evolution

NASA - Dawn Mission patch.

November 10, 2017

Surface features on Ceres -- the largest world between Mars and Jupiter -- and its interior evolution have a closer relationship than one might think.

A recent study, published in Geophysical Research Letters, analyzed Ceres' surface features to reveal clues about the dwarf planet's interior evolution. Specifically, the study explored linear features -- the chains of pits and small, secondary craters common on Ceres.

Image above: This image made with data from NASA's Dawn spacecraft shows pit chains on dwarf planet Ceres called Samhain Catenae. Image Credits: NASA/JPL-Caltech/UCLA/MPS/DLR/IDA.

The findings align with the idea that, hundreds of millions (up to a billion) years ago, materials beneath Ceres' surface pushed upward toward the exterior, creating fractures in the crust.

"As this material moved upward from underneath Ceres' surface, portions of Ceres' outer layer were pulled apart, forming the fractures," said JenniferScully, lead study author and associate of the Dawn science team at NASA's Jet Propulsion Laboratory in Pasadena, California.

The indication of upwelling material under Ceres' surface allows for another perspective in establishing how the dwarf planet may have evolved.

Searching for a Needle in a Haystack

Dawn scientists generated a map of over 2,000 linear features on Ceres greater than 0.6 mile (one kilometer) in length that are located outside of impact craters. The scientists interpreted Dawn's observations of two kinds of linear features to further understand their connection to the upwelling material. Secondary crater chains, the most common of the linear features, are long strings of circular depressions created by fragments thrown out of large impact craters as they formed on Ceres. Pit chains, on the other hand, are surface expressions of subsurface fractures.

Among the two features, only pit chains provide insight into Ceres' interior evolution. Scully said the study's greatest challenge was differentiating between secondary crater chains and pit chains. Although the features are strikingly similar, researchers were able to distinguish between them based on their detailed shapes. For example, secondary craters are comparatively rounder than pit chains, which are more irregular. In addition, pit chains lack raised rims, whereas there is usually a rim around secondary craters.

Dawn unveiling Ceres. Animation Credit: NASA

How the Features Formed

While it is possible that the freezing of a global subsurface ocean formed the fractures, this scenario is unlikely, as the locations of pit chains are not evenly dispersed across Ceres' surface. It is also unlikely that the fractures formed by stresses from a large impact because there is no evidence on Ceres of impacts substantial enough to generate fractures of that scale. The most probable explanation, according to the Dawn scientists, is that a region of upwelling material formed the pit chains. The material may have flowed upward from Ceres' interior because it is less dense than surrounding materials.

Dawn scientists look forward to seeing how these characteristics will help other researchers model Ceres' interior evolution, which can test whether upwelling may have occurred near the fractures.

Geophysical Research Letters: http://onlinelibrary.wiley.com/doi/10.1002/2017GL075086/full

The Dawn mission is managed by JPL for NASA's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team. A complete list of mission participants is at:

https://dawn.jpl.nasa.gov/mission

More information about Dawn is available at the following sites:

https://www.nasa.gov/dawn

https://dawn.jpl.nasa.gov

Image (mentioned), Animation (mentioned), Text, Credits: NASA/JPL/Elizabeth Landau.

Greetings, Orbiter.ch

Crew Tests New Workouts and Lights as Rocket Preps for Launch

ISS - Expedition 53 Mission patch.

November 9, 2017

International Space Station (ISS). Animation Credit: NASA

The Expedition 53 crew is working out on a new exercise device today and testing new lights for their impact on health. Back on Earth, a new resupply rocket stands at its launch pad ready for a Saturday launch to the International Space Station.

Astronauts Joe Acaba and Mark Vande Hei worked out on the new Mini-Exercise Device-2 (MED-2) this morning performing dead lifts and rowing exercises. The duo tested its ability to provide reliable, effective workouts despite its smaller size to increase the habitability of a spacecraft.

Vande Hei is also analyzing the station’s new solid-state light-emitting diodes that are replacing older fluorescent lights. He conducted a series of tests throughout the day to determine how they impact crew sleep patterns and cognitive performance.

Image above: The Orbital ATK Antares rocket, with the Cygnus spacecraft onboard, is raised into vertical position at the launch pad Thursday, Nov. 9, 2017 at Wallops Flight Facility in Virginia. Photo Credits: NASA/Bill Ingalls.

The Orbital ATK Cygnus cargo craft is encapsulated inside the Antares rocket and now stands vertical at the launch pad at Wallops Flight Facility in Virginia. Cygnus is due to launch Saturday at 7:37 a.m. EDT with about 7,400 pounds of new science experiments and fresh supplies for the Expedition 53 crew.

Cygnus will unfurl its cymbal-like UltraFlex solar arrays less than two hours after launch as it begins a two-day trip to the International Space Station. Astronaut Paolo Nespoli will command the Canadarm2 from the Cupola to grapple Cygnus when it arrives Monday morning at 5:40 a.m. Commander Randy Bresnik will back up Nespoli and monitor the approach and rendezvous.

Cygnus Training, Respiratory Health and Performance Studies

Two astronauts are training for Monday’s planned arrival of Orbital ATK’s newest Cygnus cargo craft dubbed the S.S. Eugene Cernan. The crew is also analyzing the International Space Station’s atmosphere and studying how crew performance adapts to microgravity.

Orbital ATK is counting down to a Veteran’s Day launch of its Cygnus spacecraft atop an Antares rocket from Wallops Flight Facility in Virginia. The rocket is scheduled to blast off Saturday at 7:37 a.m. EST with about 7,400 pounds of science gear and crew supplies packed inside Cygnus.

Commander Randy Bresnik and Flight Engineer Paolo Nespoli are training today to capture Cygnus with the Canadarm2 robotic arm. Nespoli will command the Canadarm2 to grapple Cygnus at 5:40 a.m. Monday when it reaches a point about 10 meters from the station. Bresnik will back up Nespoli and monitor the spacecraft’s approach and rendezvous.

Image above: This photograph taken on Nov. 5, 2017, shows a portion of the Himalayan mountain range as the International Space Station orbited about 250 miles above. Image Credit: NASA.

Astronaut Mark Vande Hei has been helping doctors this week understand the risk of living inside the closed environment of a spacecraft for the Airway Monitoring study. He set up gear to analyze the air in the space station for dust and gases that could inflame an astronaut’s respiratory system. Results will help doctors improve crew health as NASA plans human missions farther and longer into space.

Nespoli started his day studying how floating in space impacts interacting with touch-based technologies and other sensitive equipment. Observations from the Fine Motor Skills study may influence the design of future spaceships and space habitats.

Related links:

Expedition 53: https://www.nasa.gov/mission_pages/station/expeditions/expedition53/index.html

Orbital ATK: https://www.nasa.gov/mission_pages/station/structure/launch/orbital.html

Airway Monitoring: https://www.nasa.gov/mission_pages/station/research/experiments/1172.html

Fine Motor Skills: https://www.nasa.gov/mission_pages/station/research/experiments/1767.html

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

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

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

Best regards, Orbiter.ch

The road to Orion’s launch

NASA- Orion Multi-Purpose Crew Vehicle patch.

9 November 2017

NASA’s Orion spacecraft aims to send humans further into space than ever before, and ESA’s European Service Module will provide the essentials for keeping the astronauts alive and on course.

A review of the programme by NASA to assess progress is now showing a launch date from December 2019 to June 2020.

NASA - Exploration Mission-1 – Pushing Farther Into Deep Space

The first Exploration Mission-1 will circle the Moon without astronauts to lay the foundation and prove the technology for a second mission with a crew.

In Bremen, Germany, integration of the service module is well under way, with work already starting on the second.

More than 11 km of cables are being laid and connected to send the megabytes of information from the solar panels, fuel systems, engines, and air and water supplies to the module’s central computers.

Orion with European Service Module

Recently, the Orion’s 24 orientation thrusters were installed, complementing the eight larger engines that will back up the main engine.

The module’s complex design requires 1100 welds for the propulsion system alone, with only 173 left to complete.

Teams in Bremen at the Airbus integration room are on eight-hour shifts to keep work running 24 hours a day, aiming for a shipment of the completed module to the USA in the summer of 2018.

It will be flown to NASA’s Kennedy Space Center in Florida, where it will be combined with the crew module before they are moved to NASA’s Plum Brook station in Ohio for extensive tests to ensure they are ready for launch and the voyage into deep space.

European Service Module

The service module is based on technology from ESA’s tried-and-tested Automated Transfer Vehicles that flew to the International Space Station on five missions. For Orion, the design is more complex with more systems but the technology behind it has been miniaturised to fit into the smaller Orion structure.

ESA’s David Parker, Director of Human Spaceflight and Robotic Exploration, says: “The Orion spacecraft and service module is an inspiring international cooperation at the forefront of technology and humanity’s drive for exploration. All the teams involved are justly proud to be part of such a complex and important project.”

Related links:

ESA Orion: http://www.esa.int/Our_Activities/Human_Spaceflight/Orion

NASA Orion: https://www.nasa.gov/exploration/systems/orion/index.html

Orion at Airbus: http://www.space-airbusds.com/orion/index_EN.html

Automated Transfer Vehicle (ATV): http://www.esa.int/Our_Activities/Human_Spaceflight/ATV

Images, Text, Credits: European Space Agency (ESA)/D. Ducros.

Best regards, Orbiter.ch

Jupiter’s Stunning Southern Hemisphere

NASA - JUNO Mission logo.

Nov. 9, 2017

See Jupiter’s southern hemisphere in beautiful detail in this new image taken by NASA’s Juno spacecraft. The color-enhanced view captures one of the white ovals in the “String of Pearls,” one of eight massive rotating storms at 40 degrees south latitude on the gas giant planet.

The image was taken on Oct. 24, 2017 at 11:11 a.m. PDT (2:11 p.m. EDT), as Juno performed its ninth close flyby of Jupiter. At the time the image was taken, the spacecraft was 20,577 miles (33,115 kilometers) from the tops of the clouds of the planet at a latitude of minus 52.96 degrees. The spatial scale in this image is 13.86 miles/pixel (22.3 kilometers/pixel).

Citizen scientists Gerald Eichstädt and Seán Doran processed this image using data from the JunoCam imager.

JunoCam's raw images are available for the public to peruse and process into image products at: http://www.missionjuno.swri.edu/junocam

More information about Juno is at:

https://www.nasa.gov/juno and http://missionjuno.swri.edu

Image, Text, Credits: NASA/Tony Greicius/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt/Seán Doran.

Greetings, Orbiter.ch

NASA Completes Review of First SLS, Orion Deep Space Exploration Mission

NASA - Space Launch System (SLS) logo / NASA- Orion Multi-Purpose Crew Vehicle patch.

Nov. 8, 2017

NASA is providing an update on the first integrated launch of the Space Launch System (SLS) rocket and Orion spacecraft after completing a comprehensive review of the launch schedule.

Image above: Space Launch System (SLS) rocket and Orion spacecraft. Image Credit: NASA.

This uncrewed mission, known as Exploration Mission-1 (EM-1) is a critical flight test for the agency’s human deep space exploration goals. EM-1 lays the foundation for the first crewed flight of SLS and Orion, as well as a regular cadence of missions thereafter near the Moon and beyond.

The review follows an earlier assessment where NASA evaluated the cost, risk and technical factors of adding crew to the mission, but ultimately affirmed the original plan to fly EM-1 uncrewed. NASA initiated this review as a result of the crew study and challenges related to building the core stage of the world’s most powerful rocket for the first time, issues with manufacturing and supplying Orion’s first European service module, and tornado damage at the agency’s Michoud Assembly Facility in New Orleans.

“While the review of the possible manufacturing and production schedule risks indicate a launch date of June 2020, the agency is managing to December 2019,” said acting NASA Administrator Robert Lightfoot. “Since several of the key risks identified have not been actually realized, we are able to put in place mitigation strategies for those risks to protect the December 2019 date.”

The majority of work on NASA’s new deep space exploration systems is on track. The agency is using lessons learned from first time builds to drive efficiencies into overall production and operations planning. To address schedule risks identified in the review, NASA established new production performance milestones for the SLS core stage to increase confidence for future hardware builds. NASA and its contractors are supporting ESA’s (European Space Agency) efforts to optimize build plans for schedule flexibility if sub-contractor deliveries for the service module are late.

NASA’s ability to meet its agency baseline commitments to EM-1 cost, which includes SLS and ground systems, currently remains within original targets. The costs for EM-1 up to a possible June 2020 launch date remain within the 15 percent limit for SLS and are slightly above for ground systems. NASA’s cost commitment for Orion is through Exploration Mission-2. With NASA’s multi-mission approach to deep space exploration, the agency has hardware in production for the first and second missions, and is gearing up for the third flight. When teams complete hardware for one flight, they’re moving on to the next.

As part of the review, NASA now plans to accelerate a test of Orion’s launch abort system ahead of EM-1, and is targeting April 2019. Known as Ascent-Abort 2, the test will validate the launch abort system’s ability to get crew to safety if needed during ascent. Moving up the test date ahead of EM-1 will reduce risk for the first flight with crew, which remains on track for 2023.

Technology Advancements

On both the rocket and spacecraft, NASA is using advanced manufacturing techniques that have helped to position the nation and U.S. companies as world leaders in this area. For example, NASA is using additive manufacturing (3-D printing) on more than 100 parts of Orion. While building the two largest core stage structures of the rocket, NASA welded the thickest structures ever joined using self-reacting friction stir welding.

SLS has completed welding on all the major structures for the mission and is on track to assemble them to form the largest rocket stage ever built and complete the EM-1 “green run,” an engine test that will fire up the core stage with all four RS-25 engines at the same time.

NASA is reusing avionics boxes from the Orion EM-1 crew module for the next flight. Avionics and electrical systems provide the “nervous system” of launch vehicles and spacecraft, linking diverse systems into a functioning whole.

For ground systems, infrastructure at NASA's Kennedy Space Center in Florida is intended to support the exploration systems including launch, flight and recovery operations. The center will be able to accommodate the evolving needs of SLS, Orion, and the rockets and spacecraft of commercial partners for more flexible, affordable, and responsive national launch capabilities.

EM-1 will demonstrate safe operations of the integrated SLS rocket and Orion spacecraft, and the agency currently is studying a deep space gateway concept with U.S. industry and space station partners for potential future missions near the Moon.

“Hardware progress continues every day for the early flights of SLS and Orion. EM-1 will mark a significant achievement for NASA, and our nation’s future of human deep space exploration,” said William Gerstenmaier, associate administrator for NASA’s Human Exploration and Operations Mission Directorate in Washington. “Our investments in SLS and Orion will take us to the Moon and beyond, advancing American leadership in space.”

Related links:

Orion’s launch abort system ahead of EM-1: https://www.nasa.gov/exploration/systems/sls/core-stage-production-continues-for-rockets-first-flight

Orion Spacecraft: https://www.nasa.gov/exploration/systems/orion/index.html

Space Launch System (SLS): https://www.nasa.gov/exploration/systems/sls/index.html

Journey to Mars: https://www.nasa.gov/topics/journeytomars/index.html

Image (mentioned), Text, Credits: NASA/Sarah Loff.

Greetings, Orbiter.ch

Rare Encircling Filament

NASA - Solar Dynamics Observatory patch.

Nov. 8, 2017

NASA's Solar Dynamics Observatory came across an oddity that the spacecraft has rarely observed before: a dark filament encircling an active region (Oct. 29-31, 2017). Solar filaments are clouds of charged particles that float above the sun, tethered to it by magnetic forces. They are usually elongated and uneven strands. Only a handful of times before have we seen one shaped like a circle. The black area to the left of the brighter active region is a coronal hole, a magnetically open region of the sun. While it may have no major scientific value, it is noteworthy because of its rarity. The still was taken in a wavelength of extreme ultraviolet light.

SDO (Solar Dynamics Observatory): http://www.nasa.gov/mission_pages/sdo/main/index.html

Image, Text,  Credits: NASA/GSFC/Sarah Loff/Solar Dynamics Observatory.

Greetings, Orbiter.ch

Hot News from the Antarctic Underground

NASA logo.

November 8, 2017

Study Bolsters Theory of Heat Source Under West Antarctica

A new NASA study adds evidence that a geothermal heat source called a mantle plume lies deep below Antarctica's Marie Byrd Land, explaining some of the melting that creates lakes and rivers under the ice sheet. Although the heat source isn't a new or increasing threat to the West Antarctic ice sheet, it may help explain why the ice sheet collapsed rapidly in an earlier era of rapid climate change, and why it is so unstable today.

The stability of an ice sheet is closely related to how much water lubricates it from below, allowing glaciers to slide more easily. Understanding the sources and future of the meltwater under West Antarctica is important for estimating the rate at which ice may be lost to the ocean in the future.

Antarctica's bedrock is laced with rivers and lakes, the largest of which is the size of Lake Erie. Many lakes fill and drain rapidly, forcing the ice surface thousands of feet above them to rise and fall by as much as 20 feet (6 meters). The motion allows scientists to estimate where and how much water must exist at the base.

Image above: Illustration of flowing water under the Antarctic ice sheet. Blue dots indicate lakes, lines show rivers. Marie Byrd Land is part of the bulging "elbow" leading to the Antarctic Peninsula, left center. Image Credits: NSF/Zina Deretsky.

Some 30 years ago, a scientist at the University of Colorado Denver suggested that heat from a mantle plume under Marie Byrd Land might explain regional volcanic activity and a topographic dome feature. Very recent seismic imaging has supported this concept. When Hélène Seroussi of NASA's Jet Propulsion Laboratory in Pasadena, California, first heard the idea, however, "I thought it was crazy," she said. "I didn't see how we could have that amount of heat and still have ice on top of it."

With few direct measurements existing from under the ice, Seroussi and Erik Ivins of JPL concluded the best way to study the mantle plume idea was by numerical modeling. They used the Ice Sheet System Model (ISSM), a numerical depiction of the physics of ice sheets developed by scientists at JPL and the University of California, Irvine. Seroussi enhanced the ISSM to capture natural sources of heating and heat transport from freezing, melting and liquid water; friction; and other processes.

To assure the model was realistic, the scientists drew on observations of changes in the altitude of the ice sheet surface made by NASA's IceSat satellite and airborne Operation IceBridge campaign. "These place a powerful constraint on allowable melt rates -- the very thing we wanted to predict," Ivins said. Since the location and size of the possible mantle plume were unknown, they tested a full range of what was physically possible for multiple parameters, producing dozens of different simulations.

They found that the flux of energy from the mantle plume must be no more than 150 milliwatts per square meter. For comparison, in U.S. regions with no volcanic activity, the heat flux from Earth's mantle is 40 to 60 milliwatts. Under Yellowstone National Park -- a well-known geothermal hot spot -- the heat from below is about 200 milliwatts per square meter averaged over the entire park, though individual geothermal features such as geysers are much hotter.

Seroussi and Ivins' simulations using a heat flow higher than 150 milliwatts per square meter showed too much melting to be compatible with the space-based data, except in one location: an area inland of the Ross Sea known for intense flows of water. This region required a heat flow of at least 150-180 milliwatts per square meter to agree with the observations. However, seismic imaging has shown that mantle heat in this region may reach the ice sheet through a rift, that is, a fracture in Earth's crust such as appears in Africa's Great Rift Valley.

Mantle plumes are thought to be narrow streams of hot rock rising through Earth's mantle and spreading out like a mushroom cap under the crust. The buoyancy of the material, some of it molten, causes the crust to bulge upward. The theory of mantle plumes was proposed in the 1970s to explain geothermal activity that occurs far from the boundary of a tectonic plate, such as Hawaii and Yellowstone.

The Marie Byrd Land mantle plume formed 50 to 110 million years ago, long before the West Antarctic ice sheet came into existence. At the end of the last ice age around 11,000 years ago, the ice sheet went through a period of rapid, sustained ice loss when changes in global weather patterns and rising sea levels pushed warm water closer to the ice sheet -- just as is happening today. Seroussi and Ivins suggest the mantle plume could facilitate this kind of rapid loss.

Their paper, "Influence of a West Antarctic mantle plume on ice sheet basal conditions," was published in the Journal of Geophysical Research: Solid Earth.

NASA's Earth Science Division: https://www.nasa.gov/open/researchaccess/earth-sciences-division

NASA Earth Science News: https://www.nasa.gov/content/nasa-earth-science-news

Image (mentioned), Text, Credits: NASA's Earth Science News Team, written by Carol Rasmussen/JPL/Alan Buis.

Greetings, Orbiter.ch

Vega launches Earth observation satellite for Morocco

ARIANESPACE - Vega Flight VV11 Mission poster.


8 November 2017

Vega lifts off

Arianespace has launched a Vega rocket to deliver an Earth observation satellite into orbit for the Kingdom of Morocco.

Liftoff of Vega’s 11th mission from Europe’s Spaceport in Kourou, French Guiana came at 01:42 GMT on 8 November (02:42 CET; 22:42 local time on 7 November).

Arianespace Flight VV11 - MOHAMMED VI - A satellite

With a mass at liftoff of 1110 kg, Mohammed VI-A was manoeuvred into its target Sun-synchronous orbit about 55 minutes into the mission after a series of burns of Vega’s upper stage.

Complying with debris regulations to help keep space clean, Vega’s upper stage fired a final time to burn up high in the atmosphere over the ocean.

Mohammed VI-A satellite

Vega is a 30 m-high, four-stage vehicle designed to accommodate small scientific and Earth observation payloads of 300–2500 kg, depending on the orbit.

Related links:

Vega: http://www.esa.int/Our_Activities/Space_Transportation/Launch_vehicles/Vega

European launchers: powering Europe into space: http://spaceinvideos.esa.int/Videos/2013/02/European_launchers_powering_Europe_into_space

Arianespace: http://www.arianespace.com/

Images, Video, Text, Credits: ESA/CNES/Arianespace

Best regards, Orbiter.ch

Stressed seedlings in space

ISS - International Space Station logo.

7 November 2017

Life on Earth has a myriad of problems, but gravity isn’t one of them – staying grounded means organisms can soak up the light and heat that enables growth.

Seedlings ready to grow in EMCS

It’s no wonder that the free-floating environment of space stresses organisms, which survive only if they can adapt. Like humans, plants have proven their robustness in space. Now, thanks to the International Space Station, we know more on how they cope with weightlessness. 

Adventures of space farming

To understand how light and gravity affect plant growth, researchers from the US and Europe have grown more than 1700 thale cress seedlings in Europe’s Columbus module.

Germinated in prepacked cassettes monitored by ground control, the seedlings were harvested after six days, frozen or preserved and returned to Earth for inspection.

Researchers are now working with realtime images of the seeds as they grew and genetic and molecular analyses of the returned seedlings.

What were they hoping to find?

On Earth, roots grow down into the soil, reaching for water and minerals. Weightless disrupts this natural route, altering cell growth unless the plant can overcome it.

Seedlings growing in space

The results so far are pointing to some interesting conclusions. Obviously, seedlings in microgravity grew random roots but they still managed to grow. Plant genes known to overcome environmental stresses on Earth – heat, frost, salinity – kick into gear. Red light seems to help reregulate cell growth interrupted by weightlessness.

The most recent lettuce harvest on the Space Station shows plants can already mature in space. So why study the seedlings?

In this case, knowledge of how plants overcome gravitational stress to mature into harvestable crops is growing power.

The new results suggest gravity may not be the biggest obstacle to growing plants in space, which is good news for future Moon and Mars colonies.  We won’t make it far into space if we can’t grow our own food along the way.

Space lettuce for dinner on the ISS

Back on Earth, global climate change is affecting agriculture, and understanding how plants respond to stress and adapt at genetic and molecular levels means we can help to increase agricultural efficiency in general.

It may be a while before space farm to space table becomes the next big thing, but the latest experiments have taken us one step closer. 

Related links:

International Space Station science reports: http://www.esa.int/Our_Activities/Human_Spaceflight/Columbus/ESA_ISS_Science_System_-_Operations_Status_Report_167_Increment_39_12_25_April_2014

International Space Station Benefits for Humanity: http://www.esa.int/Our_Activities/Human_Spaceflight/International_Space_Station_Benefits_for_Humanity

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

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

Images, Text, Credits: ESA/NASA.

Best regards, Orbiter.ch

From Earth to space: developing radiation-tolerant systems

CERN - European Organization for Nuclear Research logo.

7 November 2017

Aerospace engineering and particle physics might not at first seem like obvious partners. However, both fields have to deal with radiation and other extreme environments, posing stringent technological requirements that are often similar.

Imager above: The CERN Latchup Experiment Student Satellite (CELESTA) model during RADECS-17. (Image: Enrico Chesta/CERN).

CERN operates testing facilities and develops qualification technologies for high-energy physics, which are also useful for the ground-testing and qualification of flight equipment. This opportunity is particularly attractive when it comes to testing miniaturised satellites called CubeSats, whose components are typically made using commercial off-the-shelf components, since using standard procedures to ensure radiance tolerance is expensive and time-consuming.

The CERN Latch-up Experiment Student Satellite (CELESTA) intends to develop a miniaturised and space-qualified version of RadMon, a radiation monitor developed at CERN, and to prove that CERN’s High-Energy Accelerator Mixed-Field Facility (CHARM) can be used to test whether products are suitable for low Earth orbit. CELESTA is being developed in collaboration with the University of Montpellier (link is external) (through the University Space Center and this year was selected by ESA’s Fly Your Satellite! programme to be sent into orbit in 2018 or 2019.

Many other technologies and facilities link space and accelerator radiation. The TimePix detectors, which are USB-powered particle trackers, are already used by NASA aboard the International Space Station to monitor radiation doses accurately. Monte Carlo codes such as FLUKA and Geant4, which were developed and have been maintained by worldwide collaborations with strong support from CERN since their conception, have been used routinely to study the radiation environment of past, recent and future space missions.

Magnesium diboride (MgB₂), the high-temperature superconductor that will be used for the innovative electrical-transmission lines of the High-Luminosity LHC, has also demonstrated its potential for future space missions. VESPER, the Very Energetic Electron Facility for Space Planetary Exploration Missions in Harsh Radiative Environments (part of the CERN Linear Electron Accelerator for Research (CLEAR) facility), is a high-energy electron beam line used for radiation testing and suitable for characterising electronic components for operation in Jupiter’s environment.

These synergies were in the limelight during RADECS 2017, the latest annual conference on Radiation Effects on Components and Systems, held for the first time at CERN in October this year. The aim of the RADECS conference is to provide an annual European forum on the effects of radiation on electronic and photonic materials, devices, circuits, sensors and systems. This year’s theme was “From space to ground and below”, referring to the need for radiation-tolerant systems both in space, aeronautical and terrestrial applications and in underground particle physics experiments.

Find out more at http://kt.cern/aerospace.

This text is based on an article that first appeared in the October 2017 issue of the CERN Courier.

Note:

CERN, the European Organization for Nuclear Research, is one of the world’s largest and most respected centres for scientific research. Its business is fundamental physics, finding out what the Universe is made of and how it works. At CERN, the world’s largest and most complex scientific instruments are used to study the basic constituents of matter — the fundamental particles. By studying what happens when these particles collide, physicists learn about the laws of Nature.

The instruments used at CERN are particle accelerators and detectors. Accelerators boost beams of particles to high energies before they are made to collide with each other or with stationary targets. Detectors observe and record the results of these collisions.

Founded in 1954, the CERN Laboratory sits astride the Franco–Swiss border near Geneva. It was one of Europe’s first joint ventures and now has 22 Member States.

Related links:

CERN Latch-up Experiment Student Satellite (CELESTA): http://celesta.web.cern.ch/celesta/

CERN’s High-Energy Accelerator Mixed-Field Facility (CHARM): https://kt.cern/technologies/charm

Very Energetic Electron Facility for Space Planetary Exploration Missions (VESPER): http://vesper.web.cern.ch/

High-Luminosity LHC: https://home.cern/topics/high-luminosity-lhc

University Space Center: http://csu.edu.umontpellier.fr/

For more information about European Organization for Nuclear Research (CERN), Visit: http://home.cern/

Image (mentioned), Text, Credits: CERN/Anaïs Rassat.

Best regards, Orbiter.ch

NASA Pays Tribute to Early Space Pioneer Richard Gordon

NASA logo.

November 07, 2017

Portrait of Astronaut Richard F. Gordon Jr. (10 Sept. 1964). Image Credit: NASA

The following is a statement from acting NASA Administrator Robert Lightfoot on the passing of former NASA astronaut Richard Gordon:

“NASA and the nation have lost one of our early space pioneers. We send our condolences to the family and loved ones of Gemini and Apollo astronaut Richard Gordon, a hero from NASA’s third class of astronauts. 

“Naval officer, aviator, chemist, test pilot, and astronaut were among the many hats of this talented and daring explorer. Dick was pilot of Gemini XI in 1966, on which he performed a spacewalk where he tethered the Gemini and Agena together for the very first attempt at creating artificial gravity by rotating spacecraft. He also was command module pilot of Apollo 12, the second manned mission to land on the Moon. While his crewmates Pete Conrad and Alan Bean landed in the Ocean of Storms, he remained in lunar orbit aboard the Yankee Clipper, taking photos for potential future landing sites and later performing final re-docking maneuvers.

“An accomplished naval aviator, Dick tested many new aircraft that later entered service and also won the Bendix Trophy Race from New York to Los Angeles in 1961, setting a new speed record for the time.

“Dick will be fondly remembered as one of our nation’s boldest flyers, a man who added to our own nation’s capabilities by challenging his own. He will be missed.”

For more information about Gordon’s NASA career, visit:

https://www.nasa.gov/sites/default/files/atoms/files/gordon_richard.pdf

Image (mentioned), Text, Credits: NASA/Jen Rae Wang/Allard Beutel.

R.I.P., Orbiter.ch

The Dynamic Duo: Jupiter's Independently Pulsating X-ray Auroras

NASA - Chandra X-ray Observatory patch / ESA - XMM-Newton Mission patch.

Nov. 6, 2017

Jupiter's intense northern and southern lights, or auroras, behave independently of each other according to a new study using NASA's Chandra X-ray and ESA's XMM-Newton observatories.

Using XMM-Newton and Chandra X-ray observations from March 2007 and May and June 2016, a team of researchers produced maps of Jupiter's X-ray emissions (shown in inset) and identified an X-ray hot spot at each pole. Each hot spot can cover an area equal to about half the surface of the Earth.

The team found that the hot spots had very different characteristics. The X-ray emission at Jupiter's south pole consistently pulsed every 11 minutes, but the X-rays seen from the north pole were erratic, increasing and decreasing in brightness — seemingly independent of the emission from the south pole.

This makes Jupiter particularly puzzling. X-ray auroras have never been detected from our Solar System's other gas giants, including Saturn. Jupiter is also unlike Earth, where the auroras on our planet's north and south poles generally mirror each other because the magnetic fields are similar.

To understand how Jupiter produces its X-ray auroras, the team of researchers plans to combine new and upcoming X-ray data from Chandra and XMM-Newton with information from NASA's Juno mission, which is currently in orbit around the planet. If scientists can connect the X-ray activity with physical changes observed simultaneously with Juno, they may be able to determine the process that generates the Jovian auroras and by association X-ray auroras at other planets.

One theory that the X-ray and Juno observations may help to prove or disprove is that Jupiter's X-ray auroras are caused by interactions at the boundary between Jupiter's magnetic field, which is generated by electrical currents in the planet's interior, and the solar wind, a high-speed flow of particles streaming from the Sun. The interactions between the solar wind and Jupiter's magnetic field can cause the latter to vibrate and produce magnetic waves. Charged particles can surf these waves and gain energy. Collisions of these particles with Jupiter's atmosphere produce the bright flashes of X-rays observed by Chandra and XMM. Within this theory the 11-minute interval would represent the time for a wave to travel along one of Jupiter's magnetic field lines.

The difference in behavior between the Jovian north and south poles may be caused by the difference in visibility of the two poles. Because the magnetic field of Jupiter is tilted, we are able to see much more of the northern aurora than the southern aurora. Therefore for the north pole we may be able to observe regions where the magnetic field connects to more than one location, with several different travel times, while for the south pole we can only observe regions where the magnetic field connects to one location. This would cause the behavior of the north pole to appear erratic compared to the south pole.

A larger question is how does Jupiter give the particles in its magnetosphere (the realm controlled by Jupiter's magnetic field) the huge energies needed to make X-rays? Some of the X-ray emission observed with Chandra can only be produced if Jupiter accelerates oxygen ions to such high energies that when they violently collide with the atmosphere all eight of their electrons are torn off. Scientists hope to determine what impact these particles, which crash into the planet's poles at thousands of kilometers per second, have on the planet itself. Do these high-energy particles affect the Jovian weather and the chemical composition of its atmosphere? Can they explain the anomalously high temperatures found in certain places in Jupiter's atmosphere? These are the questions that Chandra, XMM-Newton, and Juno may be able to help answer in the future.

A paper describing these results appeared in the October 30th issue of Nature Astronomy, led by William Dunn of the University College London. NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.

Read More from NASA's Chandra X-ray Observatory: http://chandra.harvard.edu/photo/2017/jupiter/

For more Chandra images, multimedia and related materials, visit: http://www.nasa.gov/chandra

Nature Astronomy paper: https://www.nature.com/articles/s41550-017-0262-6

NASA's Chandra X-ray Observatory: https://www.nasa.gov/mission_pages/chandra/main/index.html

ESA's XMM-Newton observatory: http://sci.esa.int/xmm-newton/

Image, Text, Credits: X-ray: NASA/CXC/UCL/W.Dunn et al, Optical: South Pole:Credits: NASA/JPL-Caltech/SwRI/MSSS/Gerald Eichstädt/Seán Doran North Pole Credit:NASA/JPL-Caltech/SwRI/MSSS/NASA/Lee Mohon/Chandra X-ray Center/Megan Watzke.

Greetings, Orbiter.ch

Heating ocean moon Enceladus for billions of years

ESA - Cassini Mission to Saturn logo.

Nov. 6, 2017

A paper published in Nature Astronomy today presents the first concept that explains the key characteristics of 500 km-diameter Enceladus as observed by the international Cassini spacecraft over the course of its mission, which concluded in September.

Image above: Enceladus interior. Credits: Surface: NASA/JPL-Caltech/Space Science Institute; interior: LPG-CNRS/U. Nantes/U. Angers. Graphic composition: ESA.

This includes a global salty ocean below an ice shell with an average thickness of 20–25 km, thinning to just 1–5 km over the south polar region. There, jets of water vapour and icy grains are launched through fissures in the ice. The composition of the ejected material measured by Cassini included salts and silica dust, suggesting they form through hot water – at least 90°C – interacting with rock in the porous core.

These observations require a huge source of heat, about 100 times more than is expected to be generated by the natural decay of radioactive elements in rocks in its core, as well as a means of focusing activity at the south pole.

Image above: Enceladus plumes. Image Credits: NASA/JPL/Space Science Institute.

The tidal effect from Saturn is thought to be at the origin of the eruptions deforming the icy shell by push-pull motions as the moon follows an elliptical path around the giant planet. But the energy produced by tidal friction in the ice, by itself, would be too weak to counterbalance the heat loss seen from the ocean – the globe would freeze within 30 million years.

As Cassini has shown, the moon is clearly still extremely active, suggesting something else is happening.

"Where Enceladus gets the sustained power to remain active has always been a bit of mystery, but we've now considered in greater detail how the structure and composition of the moon's rocky core could play a key role in generating the necessary energy," says lead author Gaël Choblet from the University of Nantes in France.

In the new simulations the core is made of unconsolidated, easily deformable, porous rock that water can easily permeate. As such, cool liquid water from the ocean can seep into the core and gradually heat up through tidal friction between sliding rock fragments, as it gets deeper.

Image above: Enceladus interior. Credits: Surface: NASA/JPL-Caltech/Space Science Institute; interior: LPG-CNRS/U. Nantes/U. Angers. Graphic composition: ESA.

Water circulates in the core and then rises because it is hotter than the surroundings. This process ultimately transfers heat to the base of the ocean in narrow plumes where it interacts strongly with the rocks. At the seafloor, these plumes vent into the cooler ocean.

One seafloor hotspot alone is predicted to release as much as 5 GW of energy, roughly corresponding to the annual geothermal power consumed in Iceland.

Such seafloor hotspots generate ocean plumes rising at a few centimetres per second. Not only do the plumes result in strong melting of the ice crust above, but they can also carry small particles from the seafloor, over weeks to months, which are then released into space by the icy jets.

Moreover, the authors' computer models show that most water should be expelled from the moon's polar regions, with a runaway process leading to hot spots in localised areas, and thus a thinner ice shell directly above, consistent with what was inferred from Cassini.

"Our simulations can simultaneously explain the existence of an ocean at a global scale due to large-scale heat transport between the deep interior and the ice shell, and the concentration of activity in a relatively narrow region around the south pole, thus explaining the main features observed by Cassini," says co-author Gabriel Tobie, also from the University of Nantes.

Animation above: Last Enceladus plume observation. Animation Credits: NASA/JPL-Caltech/Space Science Institute.

The scientists say that the efficient rock-water interactions in a porous core massaged by tidal friction could generate up to 30 GW of heat over tens of millions to billions of years.

"Future missions capable of analysing the organic molecules in the Enceladus plume with a higher accuracy than Cassini would be able to tell us if sustained hydrothermal conditions could have allowed life to emerge," says Nicolas Altobelli, ESA's Cassini project scientist.

A future mission equipped with ice-penetrating radar would also be able to constrain the ice thickness, and additional flybys – or an orbiting craft – would improve models of the interior, further verifying the presence of active hydrothermal plumes.

"We'll be flying next-generation instruments, including ground-penetrating radar, to Jupiter's ocean moons in the next decade with ESA's JUICE mission, which is specifically tasked with trying to understand the potential habitability of ocean worlds in the outer Solar System," adds Nicolas.

Notes for Editors:

"Powering prolonged hydrothermal activity inside Enceladus," by G. Choblet et al. is published in Nature Astronomy, 6 November 2017.
https://dx.doi.org/10.1038/s41550-017-0289-8

The Cassini-Huygens mission is a cooperative project of NASA, ESA and Italy's ASI space agency.

Related links:

ESA's Cassini mission: http://www.esa.int/Our_Activities/Space_Science/Cassini-Huygens

ESA's JUICE mission: http://sci.esa.int/juice/

Images (mentioned), Animation (mentioned), Text, Credits: ESA/Markus Bauer/Nicolas Altobelli/Université de Nantes/Gabriel Tobie/Gaël Choblet.

Best regards, Orbiter.ch