mardi 24 avril 2018

NASA Upgrades Space Station Emergency Communications Ground Stations










NASA - SCaN Mission logo.

April 24, 2018

Since the launch of the International Space Station’s first component in 1998, communications infrastructure has been critical to the station’s success and crew safety. NASA is currently implementing upgrades to very high frequency (VHF) communications ground stations that backup the station’s primary communications system, the Space Network, and communicate with Soyuz spacecraft when out of Russia’s range.

The International Space Station. Image Credit: NASA

NASA’s VHF ground stations provide two-way, audio-only communications and transmit over two frequencies, VHF1 and VHF2. VHF1 is used for emergency communications with the International Space Station. VHF2 communicates with Soyuz spacecraft.

Russia also operates a VHF network independently from NASA's. The combination of the two networks ensures VHF communications are available on every orbit of the space station and Soyuz.

The space station hosts two VHF1 antennas, 180 degrees apart. They flank the Zvezda Service Module, an early Russian contribution to the station that served as an early cornerstone for its habitation. Astronauts and cosmonauts can communicate with mission control from any module of the station via VHF1.


Image above: An upgraded VHF antenna capable of supporting both the VHF1 and VHF2 frequencies. Image Credit: NASA.

“Maintaining the availability of utility-like communications between the crew and the ground is paramount to enabling mission success and ensuring crew safety,” said Mark Severance, Human Spaceflight Communications and Tracking Network director. “The NASA VHF network, in combination with the VHF network operated by our Russian partners, does just that.”

Under normal circumstances, the station relies on NASA’s Space Network, a series of Tracking and Data Relay Satellites in geosynchronous orbit. The network provides near-continuous communications coverage between the station and mission control centers around the world who make sure the station’s systems function properly. The Space Network also enables the transmission of high-resolution science data, ultra-high definition video and special downlinks like student contacts with astronauts. VHF1 would only be used in the unlikely event that the space station was unable to communicate via the Space Network.

A Soyuz with VHF2 antenna toward the aft of the spacecraft. Image Credit: NASA

Russian Soyuz spacecraft sport a single VHF2 antenna towards their tail. Russia uses VHF2 as their primary system for voice communications from launch at the Baikonur Cosmodrome in Kazakhstan to docking with the space station and upon undocking and returning to Earth.

On most Soyuz missions, the spacecraft docks with the space station prior to exiting Russia’s VHF network coverage. The same is true on return to Earth. However, on Soyuz missions that require a longer, 34-orbit rendezvous, the NASA VHF network stands by to provide emergency communications while the Soyuz is outside of Russia’s range, orbiting over the continental United States. NASA’s VHF network could also provide emergency communications in the event a problem required the Soyuz to stay in orbit for an extended period of time.

NASA’s upgrades to VHF network ground antennas, currently underway, involve improvements to numerous electronic components and installation of new software for tracking the space station and Soyuz. Additionally, new antennas at the ground stations, able to operate at VHF1 and VHF2 simultaneously, will add redundancy to the network so that if one system fails, the other system will be able to take over immediately.


Image above: A VHF ground antenna at NASA’s Wallops Flight Facility in Wallops Island, Virginia. Image Credit: NASA.

“The purpose of these upgrades is to ensure the VHF ground stations remain a robust capability for backup and emergency communications,” said Severance. “The addition of redundancy, the ‘belt and suspenders’ approach, is particularly important given that these systems would only be employed due to failure of the primary space station communications system or an emergency onboard the Soyuz.”

NASA maintains VHF ground stations in two locations: Wallops Flight Facility in Wallops Island, Virginia, and NASA’s Armstrong Flight Research Center in Edwards, California. These ground stations are strategically placed to maximize contact with the station and Soyuz as they orbit above North America. The Russian VHF ground stations are located throughout Russia, providing contact as the space station and Soyuz orbit above Asia and Europe.

NASA’s VHF system is managed by NASA’s Goddard Space Flight Center’s Exploration and Space Communications projects division. NASA’s Space Communications and Navigation program office provides programmatic oversight to the network.

Related links:

NASA’s Goddard Space Flight Center: https://www.nasa.gov/goddard

Exploration and Space Communications : https://esc.gsfc.nasa.gov/

NASA’s Space Communications and Navigation: https://www.nasa.gov/directorates/heo/scan/index.html

SCaN (Space Communications and Navigation): https://www.nasa.gov/directorates/heo/scan/index.html

NASA’s Armstrong Flight Research Center: https://www.nasa.gov/centers/armstrong/home/index.html

Wallops Flight Facility: https://www.nasa.gov/centers/wallops/home

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

Images (mentioned), Text, Credits: NASA/Rob Garner/Goddard Space Flight Center, by Danny Baird.

Greetings, Orbiter.ch

Fuel tanks and wings for Orion module











NASA - Orion Crew Vehicle patch.

24 April 2018

The European service module that will provide power, water, air and electricity to NASA’s Orion Moon module has taken a large step closer to completion with the installation of its fuel tanks and testing of its solar wings.

Orion service module fuel tank installation

Orion will eventually fly beyond the Moon with astronauts. The first mission – without astronauts – is getting ready for launch in 2019.

The large tanks that will provide propellant for the spacecraft are now fitting snuggly inside the spacecraft at the Airbus assembly hall in Bremen, Germany.

The four tanks will each contain about 2000 litres of propellant. In the vacuum of space there is no air to burn so spacecraft fuel tanks include oxidiser and fuel that are mixed to ignite and provide thrust.

Orion service module fuel tank

The two sets of tanks are connected by intricate pipelines to 33 engines. Sensors and computers control the system.

The European service module is a small but complex spacecraft packed with equipment. The large tanks are installed as one of the last components to allow technicians more room to work.

 Orion with Service Module

ESA’s propulsion lead for Orion, Thierry Kachler, says: "Tank installation is a great achievement and a big step towards the start of the final acceptance tests in Europe."

Shaking the solar wings

Meanwhile the solar arrays Orion will use to produce electricity are being tested at ESA’s technical heart in the Netherlands. Folded for launch, the fragile solar panels need to survive the rumbling into space aboard the most powerful rocket ever built, NASA’s Space Launch System.

Orion solar wing testing

Orion’s solar panels will be folded inside the rocket fairing on the first leg of the trip around the Moon. Once released from the rocket they will unfold and rotate towards the Sun to start delivering power.

To make sure the solar panels will work after the intense launch, ESA engineers are putting them through rigorous tests that exceed what they will experience on launch day. This includes vibrating them on a shaking table and placing them in front of enormous speakers that recreate the harsh launch conditions.

Orion spacecraft exploded view

Once they pass these tests they can be sent to Bremen to join the service module.

The service module is set to ship to the USA this summer for further tests and integration with the crew module adaptor.

Related links:

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

Orion at Airbus: https://orionesm.airbusdefenceandspace.com/blog/

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

Images, Text, Credits: ESA/M. Cowan/Airbus/NASA.

Best regards, Orbiter.ch

Space smash: simulating when satellites collide








ESA - European Space Agency patch.

24 April 2018

Satellites orbiting Earth are moving at many kilometres per second – so what happens when their paths cross? Satellite collisions are rare, and their consequences poorly understood, so a new project seeks to simulate them, for better forecasting of future space debris.

Only four such collisions have taken place in the history of spaceflight so far – the majority of space debris stems from explosions of leftover propellant tanks or batteries – but they are projected to grow more common.

Satellite collisions create debris

“We want to understand what happens when two satellites collide,” explains ESA structural engineer Tiziana Cardone, overseeing the project.

“Up until now a lot of assumptions have been made about how the very high collision energy would dissipate, but we don’t have a solid understanding of the physics involved.

“We want to be able to visualise in detail how the satellites would break up, and how many pieces of debris would be produced, to improve the quality of our models and predictions.”

Simulated satellite strike

The total energy involved is orders of magnitudes higher than typical structural engineering for space, which focuses on enduring the violence of launch. “This is really unknown territory,” adds Tiziana.

“We need to have this understanding because we are currently working on expensive debris mitigation strategies based on our understanding of debris behaviour,” explains Holger Krag of ESA’s Space Debris Office. “We’re projecting the evolution of the debris environment up to 200 years ahead.

“Of the four known collisions, only one of them took place in the way we expected, with both satellites breaking up catastrophically, generating clouds of debris. The others were quite different, so there’s something missing from our picture.

Simulated debris strike

“By running many different collision variants then we hope to understand what happened across the actual collisions, to help substantiate our modelling.”

Two different kinds of software simulations are being undertaken: at Germany’s Fraunhofer Institute for High-Speed Dynamics and the other at a consortium led by the Center for Studies and Activities for Space at the University of Padua in Italy.

The first approach is based on a sophisticated numerical method to simulate the deformation and fragmentation processes in a collision. The colliding objects are modelled with realistic structural and mechanical properties, represented by a ‘finite element mesh’.

Impacting a hollow cylinder

These elements are converted into discrete particles as the satellites fragment. This allows the simulation of the satellites’ structural response to the collision as well as the generation of the fragment cloud, and its evolution over time.

The second approach treats the spacecraft as made up of larger elements, such as panels, payload, propellant tanks or solar arrays, attached together with physical links. When the energy transfer of the collision takes place, these links are broken apart and the elements are fragmented. A library of previous simulations and empirical data is applied to show how these elements fragment under the force of the impact.

Simulated debris impact

The two types of simulation together – operating at material and component levels – should give new insight into the underlying physics of collisions, but has begun by mimicking the effects of a single item of debris – the kind of collision that can be simulated physically in terrestrial labs.

Real-life impact test

Once these simulations duplicate the observed reality, then they will be used to reproduce entire impacts of 500 kg-scale satellites.

Clean Space: the challenge of space debris

The first known collision took place in 1991, when Russia’s Cosmos 1934 was struck by a piece of Cosmos 926. Then, in 1996, France’s Cerise satellite was hit by a fragment of an Ariane 4 rocket. In 2005 a US upper stage was hit by a fragment of a Chinese rocket’s third stage. In 2009 an Iridium satellite collided with Russia’s Cosmos-2251.

Related links:

Space Debris Office: http://www.esa.int/Our_Activities/Operations/Space_Debris

Fraunhofer Ernst Mach Institute: http://www.emi.fraunhofer.de/EN/index.asp

CISAS - Center for Studies and Activities for Space: http://cisas.unipd.it/

Images, Video, Text, Credits: ESA/ID&Sense/ONiRiXEL, CC BY-SA 3.0 IGO, CC BY-SA 3.0 IGO/Fraunhofer Institute for High-Speed Dynamics/ESA/Center for Studies and Activities for Space.

Greetings, Orbiter.ch

lundi 23 avril 2018

Space Station Science Highlights: Week of April 16, 2018











ISS - Expedition 55 Mission patch.

April 23, 2018

The crew members aboard the International Space Station conducted science at a slightly higher altitude last week as the space station was boosted into a higher orbit in preparation for this summer’s launching and landing activities.

International Space Station (ISS). Image Credits: NASA/STS-119

Take a look at some of the science that happened last week aboard your orbiting laboratory:

Crew relocates habitats for maintenance

Spaceflight brings an extreme environment with unique stressors. Exposure to cosmic radiation increases intracellular oxidative stresses, which can lead to DNA damage and cell death. Microgravity provokes cellular mechanical stresses and perturbs cellular signaling, leading to reduction of muscle and bone density. To overcome these space stresses, one of the promising strategies is to activate Nuclear Factor-like 2 (Nrf2), a master regulator of antioxidant pathway. Mouse Stress Defense, a JAXA investigation, tests genetically modified loss-of-Nrf2-function and gain-of-Nrf2-function in mice in the space environment and examines how Nrf2 contributes to effective prevention against the space-originated stresses.


Image above: NASA astronaut Scott Tingle works with a thawing pouch as a part of the Metabolic Tracking investigation. Image Credit: NASA.

Last week, the crew temporarily relocated the Mouse Habitat Cage Units from the Cell Biology Experiment Facility to Microgravity Science Glovebox (MSG) to perform maintenance on the units.

First harvest for APEX investigation complete

A more thorough understanding of how plants grow in space provides better life support system design and resource planning for long-term space missions. Using Brachypodium distachyon to Investigate Monocot Plant Adaptation to Spaceflight (APEX-06) is an investigation which expands our understanding of plant growth in space and provides fundamental information about plant biology on Earth.


Animation above: A view of the MISSE Sample Carrier, containing investigations from MISSE-9, being installed on to the MISSE-FF platform. Animation Credit: NASA.

Last week, the crew harvested and photographed the plants for the investigation.

New ACE investigation initiated

The Advanced Imaging, Folding, and Assembly of Colloidal Molecules (ACE-T-9) experiment involves the imaging, folding, and assembly of complex colloidal molecules within a fluid medium. This set of experiments prepares for future colloidal studies and also provides insight into the relationship between particle shape, colloidal interaction, and structure. These so-called “colloidal molecules” are vital to the design of new and more stable product mixtures.


Animation above: NASA astronaut Scott Tingle works within the Veggie facility as a part of the APEX-06 investigation. Animation Credit: NASA.

Last week, the crews finished up the previous ACE investigation (ACE-T-6) and initiated the ACE-T-9 investigation.

Space to Ground: Operating an Outpost: 04/20/2018

Other work was done on these investigations: Crew Earth Observations, Biochemical Profile, ACE-T-6, Story Time from Space, CASIS PCG-9, MSG, HDEV, CIR, SG100 Cloud Computer, MISSE-FF, TSIS, Food Acceptability, EIISS, EarthKAM, SCAN Testbed, Multi-Use Variable-g platform (MVP), Metabolic Tracking, Multi-Omics and Radi-N2.

Related links:

APEX-06: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7524

ACE-T-9: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1877

Crew Earth Observations: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=84

Biochemical Profile: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=980

ACE-T-6: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1707

Story Time from Space: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1152

CASIS PCG-9: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7627

MSG: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=341

HDEV: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=892

CIR: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=317

SG100 Cloud Computer: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=2055

MISSE-FF: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=7515

TSIS: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1907

Food Acceptability: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7562

EIISS: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7565

EarthKAM: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=87

SCAN Testbed: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=156

Multi-Use Variable-g platform (MVP): https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=1777

Metabolic Tracking: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7517

Multi-Omics: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=1689

Radi-N2: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=874

Spot the Station: https://spotthestation.nasa.gov/

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

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

Images (mentioned), Video, Text, Credits: NASA/Michael Johnson/NASA Johnson/Yuri Guinart-Ramirez, Lead Increment Scientist Expeditions 55 & 56.

Best regards, Orbiter.ch

NASA's NEOWISE Asteroid-Hunter Spacecraft -- Four Years of Data








NASA - NEOWISE Mission logo.

April 23, 2018


Animation above: This movie shows the progression of NASA's Near-Earth Object Wide-field Survey Explorer (NEOWISE) investigation for the mission's first four years following its restart in December 2013. Green dots represent near-Earth objects. Gray dots represent all other asteroids which are mainly in the main asteroid belt between Mars and Jupiter. Yellow squares represent comets. Animation Credits: NASA/JPL-Caltech/PSI.

NASA's Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE) mission has released its fourth year of survey data. Since the mission was restarted in December 2013, after a period of hibernation, the asteroid- and comet-hunter has completely scanned the skies nearly eight times and has observed and characterized 29,375 objects in four years of operations. This total includes 788 near-Earth objects and 136 comets since the mission restart.

Near-Earth objects (NEOs) are comets and asteroids that have been nudged by the gravitational attraction of the planets in our solar system into orbits that allow them to enter Earth's neighborhood. Ten of the objects discovered by NEOWISE in the past year have been classified as potentially hazardous asteroids (PHAs). Near-Earth objects are classified as PHAs, based on their size and how closely they can approach Earth's orbit.

"NEOWISE continues to expand our catalog and knowledge of these elusive and important objects,” said Amy Mainzer, NEOWISE principal investigator from NASA's Jet Propulsion Laboratory in Pasadena, California. “In total, NEOWISE has now characterized sizes and reflectivities of over 1,300 near-Earth objects since the spacecraft was launched, offering an invaluable resource for understanding the physical properties of this population, and studying what they are made of and where they have come from.”

The NEOWISE team has released an animation depicting detections made by the telescope over its four years of surveying the solar system.

More than 2.5 million infrared images of the sky were collected in the fourth year of operations by NEOWISE. These data are combined with the year one through three NEOWISE data into a single publicly available archive. That archive contains approximately 10.3 million sets of images and a database of more than 76 billion source detections extracted from those images.

Near-Earth Object Wide-field Infrared Survey Explorer (NEOWISE). Image Credit: NASA

Originally called the Wide-field Infrared Survey Explorer (WISE), the spacecraft launched in December 2009. It was placed in hibernation in 2011 after its primary astrophysics mission was completed. In September 2013, it was reactivated, renamed NEOWISE and assigned a new mission: to assist NASA's efforts to identify and characterize the population of near-Earth objects. NEOWISE also is characterizing more distant populations of asteroids and comets to provide information about their sizes and compositions.

NASA's Jet Propulsion Laboratory in Pasadena, California, manages and operates the NEOWISE mission for NASA's Planetary Defense Coordination Office within the Science Mission Directorate in Washington. The Space Dynamics Laboratory in Logan, Utah, built the science instrument. Ball Aerospace & Technologies Corp. of Boulder, Colorado, built the spacecraft. Science data processing takes place at the Infrared Processing and Analysis Center at Caltech in Pasadena. Caltech manages JPL for NASA.

To review the latest data release from NEOWISE, please visit: http://wise2.ipac.caltech.edu/docs/release/neowise/

For more information about NEOWISE, visit:

https://www.nasa.gov/neowise

http://neowise.ipac.caltech.edu/

More information about asteroids and near-Earth objects is at: https://www.jpl.nasa.gov/asteroidwatch

To learn more about NASA’s efforts for Planetary Defense see: https://www.nasa.gov/planetarydefense/overview

Animation (mentioned), Image (mentioned), Text, Credits: NASA/JoAnna Wendel/Jon Nelson/JPL/DC Agle.

Greetings, Orbiter.ch

Jupiter’s Great Red Spot, Spotted












NASA - JUNO Mission patch.

April 23, 2018


This image of Jupiter’s iconic Great Red Spot and surrounding turbulent zones was captured by NASA’s Juno spacecraft.

The color-enhanced image is a combination of three separate images taken on April 1 between 3:09 a.m. PDT (6:09 a.m. EDT) and 3:24 a.m. PDT (6:24 a.m. EDT), as Juno performed its 12th close flyby of Jupiter. At the time the images were taken, the spacecraft was 15,379 miles (24,749 kilometers) to 30,633 miles (49,299 kilometers) from the tops of the clouds of the planet at a southern latitude spanning 43.2 to 62.1 degrees.

Juno spacecraft orbiting Jupiter

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

Greetings, Orbiter.ch

vendredi 20 avril 2018

New Research Activated as Biological Samples Packed for Earth Return Aboard Dragon











ISS - Expedition 55 Mission patch.

April 20, 2018

The outside of the International Space Station is a harsh environment but scientists are taking advantage of the extreme conditions to conduct advanced space research. Astronauts are also researching what happens to a variety of organisms living for months at a time inside a spacecraft as NASA prepares for longer missions farther out into space.


Image above: NASA astronaut Scott Tingle tends to plants grown inside the VEGGIE facility in support of space botany research. Image Credit: NASA.

The fifth and final external materials experiment (MISSE) delivered by the latest SpaceX Dragon resupply ship was activated outside the orbital lab today. Robotics engineers operating the Canadarm2 and Dextre extracted and installed the MISSE canisters one by one from Dragon’s trunk to areas on the station. The canisters were then remotely opened exposing a variety of materials to the vacuum of space to help engineers design safer and stronger spacecraft systems.

Back inside the orbital lab, Flight Engineer Scott Tingle of NASA harvested and photographed plants for the APEX-06 study today. The botanical samples collected from the VEGGIE facility were later processed and stowed in a science freezer for return to Earth inside the Dragon cargo craft. They will be analyzed after being quickly shipped to scientists at NASA and the University of Wisconsin.

NASA Flight Engineers Ricky Arnold and Drew Feustel once again partnered up and collected their blood and urine samples today for more biomedical experiments. Researchers are analyzing the samples as they continuously study how the human body adapts to extended periods of weightlessness. Results will help doctors provide therapies to maintain the health of astronauts in space and humans on Earth.


Image above: "The Enchanted Islands of #Ecuador – the Galápagos," were photographed by NASA astronaut Ricky Arnold, currently aboard the International Space Station with the Expedition 55 crew. This view from more than 200 miles above our Earth shows the cloud-covered Galápagos Islands and sunglint in the waters off the coast of Ecuador on April 13, 2018, as the station orbited above the Pacific Ocean. Image Credit: NASA/Ricky Arnold.

Mice are also being observed on the space station so scientists can detect the chemical signals that lead to weakened bones and muscles. Japanese astronaut Norishige Kanai drew more blood samples from the rodents today and wrapped up a week-long run of the Mouse Stress Defense experiment. The blood samples will be processed in a centrifuge, stowed in biological science freezer then returned to Earth inside Dragon for analysis on Earth.

Related links:

MISSE: https://www.nasa.gov/centers/armstrong/features/SpaceX_Dragon_Brings_Material_Samples_to_ISS.html

APEX-06: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Investigation.html?#id=7524

VEGGIE facility: https://www.nasa.gov/mission_pages/station/research/experiments/explorer/Facility.html?#id=374

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

Expedition 55: https://www.nasa.gov/mission_pages/station/expeditions/expedition55/index.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

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

Best regards, Orbiter.ch