Members Can Post Anonymously On This Site
Firefoxes and whale spouts light up Earth's shield
-
Similar Topics
-
By European Space Agency
On 1 December 2024, BepiColombo flew past Mercury for the fifth time. During this flyby, BepiColombo became the first spacecraft ever to observe Mercury in mid-infrared light. The new images reveal variations in temperature and composition across the planet's cratered surface.
View the full article
-
By NASA
Through the Artemis campaign, NASA will land the next American astronauts and first international astronaut on the South Pole region of the Moon. On Thursday, NASA announced the latest updates to its lunar exploration plans.
Experts discussed results of NASA’s investigation into its Orion spacecraft heat shield after it experienced an unexpected loss of charred material during re-entry of the Artemis I uncrewed test flight. For the Artemis II crewed test flight, engineers will continue to prepare Orion with the heat shield already attached to the capsule. The agency also announced it is now targeting April 2026 for Artemis II and mid-2027 for Artemis III. The updated mission timelines also reflect time to address the Orion environmental control and life support systems.
“The Artemis campaign is the most daring, technically challenging, collaborative, international endeavor humanity has ever set out to do,” said NASA Administrator Bill Nelson. “We have made significant progress on the Artemis campaign over the past four years, and I’m proud of the work our teams have done to prepare us for this next step forward in exploration as we look to learn more about Orion’s life support systems to sustain crew operations during Artemis II. We need to get this next test flight right. That’s how the Artemis campaign succeeds.”
The agency’s decision comes after an extensive investigation of an Artemis I heat shield issue showed the Artemis II heat shield can keep the crew safe during the planned mission with changes to Orion’s trajectory as it enters Earth’s atmosphere and slows from nearly 25,000 mph to about 325 mph before its parachutes unfurl for safe splashdown in the Pacific Ocean.
“Throughout our process to investigate the heat shield phenomenon and determine a forward path, we’ve stayed true to NASA’s core values; safety and data-driven analysis remained at the forefront,” said Catherine Koerner, associate administrator, Exploration Systems Development Mission Directorate at NASA Headquarters in Washington. “The updates to our mission plans are a positive step toward ensuring we can safely accomplish our objectives at the Moon and develop the technologies and capabilities needed for crewed Mars missions.”
NASA will continue stacking its SLS (Space Launch System) rocket elements, which began in November, and prepare it for integration with Orion for Artemis II.
Throughout the fall months, NASA, along with an independent review team, established the technical cause of an issue seen after the uncrewed Artemis I test flight in which charred material on the heat shield wore away differently than expected. Extensive analysis, including from more than 100 tests at unique facilities across the country, determined the heat shield on Artemis I did not allow for enough of the gases generated inside a material called Avcoat to escape, which caused some of the material to crack and break off. Avcoat is designed to wear away as it heats up and is a key material in the thermal protection system that guards Orion and its crew from the nearly 5,000 degrees Fahrenheit of temperatures that are generated when Orion returns from the Moon through Earth’s atmosphere. Although a crew was not inside Orion during Artemis I, data shows the temperature inside Orion remained comfortable and safe had crew been aboard.
Engineers already are assembling and integrating the Orion spacecraft for Artemis III based on lessons learned from Artemis I and implementing enhancements to how heat shields for crewed returns from lunar landing missions are manufactured to achieve uniformity and consistent permeability. The skip entry is needed for return from speeds expected for lunar landing missions.
“Victor, Christina, Jeremy, and I have been following every aspect of this decision and we are thankful for the openness of NASA to weigh all options and make decisions in the best interest of human spaceflight. We are excited to fly Artemis II and continue paving the way for sustained human exploration of the Moon and Mars,” said Reid Wiseman, NASA astronaut and Artemis II commander. “We were at the agency’s Kennedy Space Center in Florida recently and put eyes on our SLS rocket boosters, the core stage, and the Orion spacecraft. It is inspiring to see the scale of this effort, to meet the people working on this machine, and we can’t wait to fly it to the Moon.”
Wiseman, along with NASA astronauts Victor Glover and Christina Koch and CSA (Canadian Space Agency) astronaut Jeremy Hansen, will fly aboard the 10-day Artemis II test flight around the Moon and back. The flight will provide valuable data about Orion systems needed to support crew on their journey to deep space and bring them safely home, including air revitalization in the cabin, manual flying capabilities, and how humans interact with other hardware and software in the spacecraft.
With Artemis, NASA will explore more of the Moon than ever before, learn how to live and work farther away from home, and prepare for future human exploration of the Red Planet. NASA’s SLS, exploration ground systems, and Orion spacecraft, along with the human landing system, next-generation spacesuits, Gateway lunar space station, and future rovers are NASA’s foundation for deep space exploration.
For more information about Artemis, visit:
https://www.nasa.gov/artemis
-end-
Meira Bernstein / Rachel Kraft
Headquarters, Washington
202-358-1600
meira.b.bernstein@nasa.gov / rachel.h.kraft@nasa.gov
Share
Details
Last Updated Dec 05, 2024 LocationNASA Headquarters Related Terms
Missions Artemis Artemis 2 Exploration Systems Development Mission Directorate NASA Directorates View the full article
-
By NASA
The Artemis II Orion spacecraft is lifted from the Final Assembly and Testing (FAST) Cell and placed in the west altitude chamber inside the Operations and Checkout Building at NASA’S Kennedy Space Center in Florida on June 28, 2024. Inside the altitude chamber, the spacecraft underwent a series of tests simulating deep space vacuum conditions.Photo Credit: NASA / Rad Sinyak After extensive analysis and testing, NASA has identified the technical cause of unexpected char loss across the Artemis I Orion spacecraft’s heat shield.
Engineers determined as Orion was returning from its uncrewed mission around the Moon, gases generated inside the heat shield’s ablative outer material called Avcoat were not able to vent and dissipate as expected. This allowed pressure to build up and cracking to occur, causing some charred material to break off in several locations.
“Our early Artemis flights are a test campaign, and the Artemis I test flight gave us an opportunity to check out our systems in the deep space environment before adding crew on future missions,” said Amit Kshatriya, deputy associate administrator, Moon to Mars Program Office, NASA Headquarters in Washington. “The heat shield investigation helped ensure we fully understand the cause and nature of the issue, as well as the risk we are asking our crews to take when they venture to the Moon.”
Findings
Teams took a methodical approach to understanding and identifying the root cause of the char loss issue, including detailed sampling of the Artemis I heat shield, review of imagery and data from sensors on the spacecraft, and comprehensive ground testing and analysis.
During Artemis I, engineers used the skip guidance entry technique to return Orion to Earth. This technique provides more flexibility by extending the range Orion can fly after the point of reentry to a landing spot in the Pacific Ocean. Using this maneuver, Orion dipped into the upper part of Earth’s atmosphere and used atmospheric drag to slow down. Orion then used the aerodynamic lift of the capsule to skip back out of the atmosphere, then reenter for final descent under parachutes to splashdown.
Using Avcoat material response data from Artemis I, the investigation team was able to replicate the Artemis I entry trajectory environment — a key part of understanding the cause of the issue — inside the arc jet facilities at NASA’s Ames Research Center in California. They observed that during the period between dips into the atmosphere, heating rates decreased, and thermal energy accumulated inside the heat shield’s Avcoat material. This led to the accumulation of gases that are part of the expected ablation process. Because the Avcoat did not have “permeability,” internal pressure built up, and led to cracking and uneven shedding of the outer layer.
After NASA’s Orion spacecraft was recovered at the conclusion of the Artemis I test flight and transported to NASA’s Kennedy Space Center in Florida, its heat shield was removed from the crew module inside the Operations and Checkout Building and rotated for inspection. Credit: NASA Teams performed extensive ground testing to replicate the skip phenomenon before Artemis I. However, they tested at much higher heating rates than the spacecraft experienced in flight. The high heating rates tested on the ground allowed the permeable char to form and ablate as expected, releasing the gas pressure. The less severe heating seen during the actual Artemis I reentry slowed down the process of char formation, while still creating gases in the char layer. Gas pressure built up to the point of cracking the Avcoat and releasing parts of the charred layer. Recent enhancements to the arc jet facility have enabled a more accurate reproduction of the Artemis I measured flight environments, so that this cracking behavior could be demonstrated in ground testing.
While Artemis I was uncrewed, flight data showed that had crew been aboard, they would have been safe. The temperature data from the crew module systems inside the cabin were also well within limits and holding steady in the mid-70s Fahrenheit. Thermal performance of the heat shield exceeded expectations.
Engineers understand both the material phenomenon and the environment the materials interact with during entry. By changing the material or the environment, they can predict how the spacecraft will respond. NASA teams unanimously agreed the agency can develop acceptable flight rationale that will keep crew safe using the current Artemis II heat shield with operational changes to entry.
NASA’s Investigation Process
Soon after NASA engineers discovered the condition on the Artemis I heat shield, the agency began an extensive investigation process, which included a multi-disciplinary team of experts in thermal protection systems, aerothermodynamics, thermal testing and analysis, stress analysis, material test and analysis, and many other related technical areas. NASA’s Engineering and Safety Center was also engaged to provide technical expertise including nondestructive evaluation, thermal and structural analysis, fault tree analysis, and other testing support.
“We took our heat shield investigation process extremely seriously with crew safety as the driving force behind the investigation,” said Howard Hu, manager, Orion Program, NASA’s Johnson Space Center in Houston. “The process was extensive. We gave the team the time needed to investigate every possible cause, and they worked tirelessly to ensure we understood the phenomenon and the necessary steps to mitigate this issue for future missions.”
The Artemis I heat shield was heavily instrumented for flight with pressure sensors, strain gauges, and thermocouples at varying ablative material depths. Data from these instruments augmented analysis of physical samples, allowing the team to validate computer models, create environmental reconstructions, provide internal temperature profiles, and give insight into the timing of the char loss.
Approximately 200 Avcoat samples were removed from the Artemis I heat shield at NASA’s Marshall Space Flight Center in Alabama for analysis and inspection. The team performed non-destructive evaluation to “see” inside the heat shield.
One of the most important findings from examining these samples was that local areas of permeable Avcoat, which had been identified prior to the flight, did not experience cracking or char loss. Since these areas were permeable at the start of the entry, the gases produced by ablation were able to adequately vent, eliminating the pressure build up, cracking, and char loss.
A test block of Avcoat undergoes heat pulse testing inside an arc jet test chamber at NASA’s Ames Research Center in California. The test article, configured with both permeable (upper) and non-permeable (lower) Avcoat sections for comparison, helped to confirm understanding of the root cause of the loss of charred Avcoat material that engineers saw on the Orion spacecraft after the Artemis I test flight beyond the Moon.Credit: NASA
Engineers performed eight separate post-flight thermal test campaigns to support the root cause analysis, completing 121 individual tests. These tests took place in facilities with unique capabilities across the country, including the Aerodynamic Heating Facility at the Arc-Jet Complex at Ames to test convective heating profiles with various test gases; the Laser Hardened Materials Evaluation Laboratory at Wright‐Patterson Air Force Base in Ohio to test radiative heating profiles and provide real-time radiography; as well as the Interaction Heating Facility at Ames to test combined convective and radiative heating profiles in the air at full-block scale.
Aerothermal experts also completed two hypersonic wind tunnel test campaigns at NASA’s Langley Research Center in Virginia and CUBRC aerodynamic test facilities in Buffalo, New York, to test a variety of char loss configurations and enhance and validate analytical models. Permeability testing was also performed at Kratos in Alabama, the University of Kentucky, and Ames to help further characterize the Avcoat’s elemental volume and porosity. The Advanced Light Source test facility, a U.S. Department of Energy scientific user facility at Lawrence Berkeley National Laboratory, was also used by engineers to examine the heating behavior of the Avcoat at a microstructure level.
In the spring of 2024, NASA stood up an independent review team to conduct an extensive review of the agency’s investigation process, findings, and results. The independent review was led by Paul Hill, a former NASA leader who served as the lead space shuttle flight director for Return to Flight after the Columbia accident, led NASA’s Mission Operations Directorate, and is a current member of the agency’s Aerospace Safety Advisory Panel. The review occurred over a three-month period to assess the heat shield’s post-flight condition, entry environment data, ablator thermal response, and NASA’s investigation progress. The review team agreed with NASA’s findings on the technical cause of the physical behavior of the heat shield.
Heat Shield Advancements
Knowing that permeability of Avcoat is a key parameter to avoid or minimize char loss, NASA has the right information to assure crew safety and improve performance of future Artemis heat shields. Throughout its history, NASA has learned from each of its flights and incorporated improvements into hardware and operations. The data gathered throughout the Artemis I test flight has provided engineers with invaluable information to inform future designs and refinements. Lunar return flight performance data and a robust ground test qualification program improved after the Artemis I flight experience are supporting production enhancements for Orion’s heat shield. Future heat shields for Orion’s return from Artemis lunar landing missions are being produced to achieve uniformity and consistent permeability. The qualification program is currently being completed along with the production of more permeable Avcoat blocks at NASA’s Michoud Assembly Facility in New Orleans.
For more information about NASA’s Artemis campaign, visit:
https://www.nasa.gov/artemis
View the full article
-
By USH
A rare and intriguing phenomenon has been observed in China. On the night of October 27th, Chinese astrophotographer Shengyu Li set up his camera to capture star trails over Mount Xiannairi in Sichuan Province. To his surprise, he recorded mysterious blue flashes accompanying an avalanche.
The exact cause of these "blue lights" remains unclear, sparking various theories. Some speculate they could stem from geomagnetic activity, interactions of cosmic rays in the upper atmosphere, or rare atmospheric phenomena like blue jets or elves. However, Li offers another explanation: the flashes might result from triboluminescence—light produced by friction during ice fragmentation.
Triboluminescence occurs when certain materials emit light as they are fractured, scratched, or rubbed. This phenomenon happens due to the breaking of chemical bonds or the sudden separation of surfaces, which generates electrical charges. These charges can ionize the surrounding air or excite the material itself, creating visible light.
The hypothesis suggests that this event could be an example of triboluminescence. However, it also raises the intriguing possibility of a connection to UFO phenomena, such as orbs or other unexplained lights that have been observed around the world over the years.
Hypothesis: The sighting depicts what appears to be a blue light descending onto a snowbank, following the avalanche as it moves downward, and then vanishing before seemingly ascending again.
Did the avalanche trigger the blue light, or did the blue light crash into the snow, causing the avalanche?
Whether this phenomenon is a rare case of triboluminescence, potentially the first instance of it being captured on camera or something linked to unexplained UFO activity, the recording of this light remains a unique and fascinating occurrence. View the full article
-
-
-
Check out these Videos
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.