https://twitter.com/ViKu1111/status/750231247994155009?
NASA Astronomy Picture of the Day
April 22, 2024
Moon and Smoke Rings from Mt. Etna
Yes, but can your volcano do this? To the surprise of some, Mt. Etna emits, on occasion, smoke rings. Technically known as vortex rings, the walls of the volcano slightly slow the outside of emitted smoke puffs, causing the inside gas to move faster. A circle of low pressure develops so that the emitted puff of volcanic gas and ash loops around in a ring, a familiar geometric structure that can be surprisingly stable as it rises. Smoke rings are quite rare and need a coincidence of the right geometry of the vent, the right speed of ejected smoke, and the relative calmness of the outside atmosphere. In the featured image taken about two weeks ago from Gangi, Sicily, Italy, multiple volcanic smoke rings are visible. The scene is shaded by the red light of a dawn Sun, while a crescent Moon is visible in the background.
https://apod.nasa.gov/apod/astropix.html?
New Resource Speeds Access to Environmental Justice Data
Apr 22, 2024
Earth Day might occur only on April 22, but sensors aboard NASA’s constellation of Earth observation satellites are collecting data every day that can be used in a wide range of research. A new NASA resource makes it easier to locate data in the agency’s Earth science collection that can be used to further environmental justice and climate justice efforts.
The NASA Environmental Justice Data Search Interface lets you search through hundreds of datasets from multiple missions and view results in list or table view. The interface is another element of the agency’s commitment to environmental justice. NASA’s Earth Science Data Systems (ESDS) Program strives to broaden the impact of NASA’s Earth science data by engaging with a diverse community that can use these data for societal benefit and by providing a wealth of resources that can be utilized to better understand and help mitigate environmental and climate-related injustices around the world.
The new interface enables users to conduct a general search or search within eight focus areas, such as Climate Change, Extreme Heat, Urban Flooding, and Water Availability. Search results can be viewed as a list or as a configurable table that can include general information about a dataset, its strengths and limitations, data format, spatial/temporal resolution, and links to the dataset. A tutorial for using the search portal is available through the home page; a video about the search interface provides an overview.
The Environmental Justice Data Search Interface is powered by NASA’s Science Discovery Engine. The Science Discovery Engine (SDE) is an integrated search capability of NASA’s Science Mission Directorate that enables discovery of open data and information across the Directorate’s five divisions: Astrophysics, Biological and Physical Sciences, Earth Science, Heliophysics, and Planetary Science.
While Earth Day may be celebrated on one day each year, NASA’s Environmental Justice Data Search Interface—along with all the other resources NASA provides fully, openly, and without restriction—is yours to use every day.
https://www.earthdata.nasa.gov/news/new-resource-speeds-access-environmental-justice-data
China launches second Yaogan-42 reconnaissance satellite
April 22, 2024
China launched its second Yaogan-42 reconnaissance satellite over the weekend, weeks after sending the first such satellite into a similar orbit.
A Long March 2D rocket lifted off from Xichang Satellite Launch Center at 7:45 p.m. Eastern (2334 UTC) April 20. The China Aerospace Science and Technology Corporation (CASC) announced launch success within the hour.
CASC’s statement revealed the previously undisclosed payload to be the second batch of Yaogan-42 satellites. Yaogan translates to “remote sensing”.
Neither CASC nor Chinese state media provided any details regarding the satellites. These statements omitted usual general descriptions of Yaogan satellites.
Some Yaogan satellites are described as being for purposes including land survey, crop yield estimation, environmental management, meteorological warning and forecasting, and disaster prevention and reduction. Uses of others include “electromagnetic environment detection and related technical tests.”
Yaogan-42 (02) has been tracked by U.S. Space Force’s 18th Space Defense Squadron (SDS) in a 491 by 502 kilometer orbit inclined by 35 degrees. This is similar to the first Yaogan-42 satellite, launched April 2, but with an angular separation of 142 degrees.
Outside observers assess Yaogan series satellites to be designated for military and civilian purposes.The various series of Yaogan satellites are understood to include optical imaging, synthetic aperture radar (SAR) and electronic intelligence (ELINT) satellites.
This combination provides high-resolution imagery and all-weather and all-day and night imagery, along with the collection of electronic signals from radar, communication systems and other electronic devices, with coverage of both land and sea.
U.S. concerns over Chinese reconnaissance satellites
U.S. Officials have recently voiced concern over China’s buildup of reconnaissance satellites. Chief Master Sgt. Ron Lerch, of the Space Systems Command’s intelligence directorate, warned in January that China’s reconnaissance spacecraft are providing the People’s Liberation Army unprecedented eyes in space to track U.S. and allies’ activities in Asia-Pacific and other hotspots.
Notable additions to the series include Yaogan-41 to geosynchronous orbit in late 2023. That satellite launched on a Long March 5, China’s largest operational rocket. The mission used a new, elongated 18.5-meter-long, 5.2-meter-diameter payload fairing. Meanwhile, China launched Ludi Tance-4, thought to be the world’s first geosynchronous orbit SAR satellite, in August last year.
“Paired with data from other Chinese surveillance satellites, Yaogan-41 could provide China an unprecedented ability to identify and track car-sized objects throughout the entire Indo-Pacific region and put at risk numerous U.S. and allied naval and air assets operating in the region,” Clayton Swope, a former U.S. intelligence official and now a senior fellow at the Center for Strategic and International Studies, said in January.
Saturday’s launch was China’s 17th orbital mission of 2024. The country is aiming to launch around 100 times across 2024. Around 70 will be conducted by CASC, with China’s commercial launch service providers planning around 30 launches.
CASC will launch two major missions in the next couple of weeks. The Shenzhou-18 human spaceflight mission to the Tiangong space station is due to launch April 25 from Jiuquan, northwest China. The first-ever lunar far side sample return mission, Chang’e-6, is scheduled to launch May 3 from Wenchang.
https://spacenews.com/china-launches-second-yaogan-42-reconnaissance-satellite/