OrbitalHub

NASA dicit:

Understanding how fire spreads and behaves in space is crucial for the safety of future astronauts and for understanding and controlling fire here on Earth.

The primary focus of microgravity combustion experiments has been related to either fire safety in space or better understanding of practical combustion on Earth and in space. The reduced gravity creates flames that look a lot different from the ones seen here on Earth: with the near absence of gravity on the space station, flames tend to be spherical. On Earth, hot gasses from the flame rise while gravity pulls cooler, denser air to the bottom of the flame. This creates both the shape of the flame, as well as a flickering effect. In microgravity, this flow doesn’t occur. This reduces the variables in combustion experiments, making them simpler and creating spherical shaped flames.

Video Credit: NASA

NASA dicit:

A terrain relative navigation system developed by Draper of Cambridge, Massachusetts, will be tested on a Masten Space Systems Xodiac rocket. The flight is made possible with support from NASA’s Flight Opportunities and Game Changing Development programs. The Draper technology will eventually be ported directly into a NASA-developed descent landing computer for additional testing.

This video shows one of a series of tether tests of the navigation system mounted on the rocket. Tether tests like this ensure the rocket and navigation technology are communicating before the actual suborbital launch and landing.

NASA and commercial partners are relying on the most advanced technology to upgrade navigation for future robotic and crewed missions to the Moon. The agency is developing a suite of precision landing technologies for possible use on future commercial lunar landers.

Video Credit: NASA

NASA dicit:

High temperatures and low humidity are two essential factors behind the rise in fire risk and activity, affecting fire behavior from its ignition to its spread. Even before a fire starts they set the stage, said Jim Randerson, an Earth system scientist at the University of California, Irvine who studies fires both in the field and with satellite data.

He and his colleagues studied the abundance of lightning strikes in the 2015 Alaskan fire season that burned a record 5.1 million acres. Lightning strikes are the main natural cause of fires. The researchers found an unusually high number of lightning strikes occurred, generated by the warmer temperatures that cause the atmosphere to create more convective systems — thunderstorms — which ultimately contributed to more burned area that year.

Video Credit: NASA

Wikipedia dicit:

The construction of the initial test article—the “Starship test flight rocket” “test hopper,” “Starship Hopper” or “Starhopper” —was begun in early December 2018 and the external frame and skin was complete by 10 January 2019. Constructed outside in the open on a SpaceX property just two miles (3.2 km) from Boca Chica Beach in South Texas, the external body of the rocket rapidly came together in less than six weeks. Originally thought by watchers of construction at the SpaceX South Texas Launch Site to be the initial construction of a large water tower, the stainless steel vehicle was built by welders and construction workers in more of a shipyard form of construction than traditional aerospace manufacturing. The full Starhopper vehicle is 9 meters (30 ft) in diameter and was originally 39 meters (128 ft) tall in January 2019. Subsequent wind damage to the nose cone of the vehicle resulted in a SpaceX decision to scrap the nose section, and fly the low-velocity hopper tests with no nose cone, resulting in a much shorter test vehicle.

Video Credit: SpaceX

Wikipedia dicit:

Advanced Extremely High Frequency (AEHF) is a series of communications satellites operated by the United States Air Force Space Command. They will be used to relay secure communications for the Armed Forces of the United States, the British Armed Forces, the Canadian Armed Forces, the Royal Netherlands Armed Forces and the Australian Defence Force. The system will consist of six satellites in geostationary orbits, five of which have been launched. AEHF is backward compatible with, and will replace, the older Milstar system and will operate at 44 GHz Uplink (EHF band) and 20 GHz Downlink (SHF band). AEHF systems is a joint service communications system that will provide survivable, global, secure, protected, and jam-resistant communications for high-priority military ground, sea and air assets. It is the follow-on to the Milstar system. AEHF systems’ uplinks and crosslinks will operate in the extremely high frequency (EHF) range and downlinks in the super high frequency (SHF) range.

AEHF satellites use a large number of narrow spot beams directed towards the Earth to relay communications to and from users. Crosslinks between the satellites allow them to relay communications directly rather than via a ground station. The satellites are designed to provide jam-resistant communications with a low probability of interception. They incorporate frequency-hopping radio technology, as well as phased array antennas that can adapt their radiation patterns in order to block out potential sources of jamming.

Video Credit: ULA

Wikipedia dicit:

Hurricane Dorian is a strong tropical cyclone currently affecting the Bahamas and the Southeastern United States. The fourth named storm, second hurricane, and first major hurricane of the 2019 Atlantic hurricane season, Dorian developed from a tropical wave on August 24 in the Central Atlantic. The system gradually intensified while moving toward the Lesser Antilles, before becoming a hurricane on August 28. Rapid intensification ensued, and on August 31, Dorian intensified into a Category 4 major hurricane. On the following day, Dorian reached Category 5 intensity, peaking with one-minute sustained winds of 185 mph (295 km/h) and a minimum central pressure of 910 millibars (26.87 inHg) while making landfall in Elbow Cay, Bahamas, at 16:40 UTC. Dorian made another landfall on Grand Bahama several hours later, near the same intensity.

From August 26–28, the storm affected Caribbean nations and territories devastated by hurricanes Irma and Maria in 2017. Extensive precautionary measures were taken to mitigate damage, especially in Puerto Rico, where one person died. Damaging winds primarily affected the Virgin Islands where gusts reached 111 mph (179 km/h). Elsewhere in the Lesser Antilles, impacts from the storm were relatively minor.

Video Credit: NASA