OrbitalHub

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

NASA dicit:

NASA’s Transiting Exoplanet Survey Satellite (TESS) has discovered a world between the sizes of Mars and Earth orbiting a bright, cool, nearby star. The planet, called L 98-59b, marks the smallest found by TESS yet.

Two other worlds orbit the same star. While all three planets’ sizes are known, further study with other telescopes will be needed to determine if they have atmospheres and, if so, which gases are present. The L 98-59 worlds nearly double the number of small exoplanets — that is, planets beyond our solar system — that have the best potential for this kind of follow-up.

L 98-59b is around 80 Earth’s size and about 10 smaller than the previous record holder discovered by TESS. Its host star, L 98-59, is an M dwarf about one-third the mass of the Sun and lies about 35 light-years away in the southern constellation Volans. While L 98-59b is a record for TESS, even smaller planets have been discovered in data collected by NASA’s Kepler satellite, including Kepler-37b, which is only 20 larger than the Moon.

The two other worlds in the system, L 98-59c and L 98-59d, are respectively around 1.4 and 1.6 times Earth’s size. All three were discovered by TESS using transits, periodic dips in the star’s brightness caused when each planet passes in front of it.

Video Credit: NASA’s Goddard Space Flight Center/Chris Smith (USRA): producer and lead animator/Jeanette Kazmierczak (UMCP): Science Writer

Wikipedia dicit:

The Aerojet Rocketdyne RS-25, otherwise known as the Space Shuttle main engine (SSME), is a liquid-fuel cryogenic rocket engine that was used on NASA’s Space Shuttle. NASA is planning to continue using the RS-25 on the Space Shuttle’s successor, the Space Launch System (SLS).

Designed and manufactured in the United States by Rocketdyne (later known as Pratt & Whitney Rocketdyne and Aerojet Rocketdyne), the RS-25 burns cryogenic liquid hydrogen and liquid oxygen propellants, with each engine producing 1,859 kN (418,000 lbf) of thrust at liftoff. Although the RS-25 can trace its heritage back to the 1960s, concerted development of the engine began in the 1970s, with the first flight, STS-1, occurring on April 12, 1981. The RS-25 has undergone several upgrades over its operational history to improve the engine’s reliability, safety, and maintenance load.

The engine produces a specific impulse (Isp) of 452 seconds (4.43 km/s) in a vacuum, or 366 seconds (3.59 km/s) at sea level, has a mass of approximately 3.5 tonnes (7,700 pounds), and is capable of throttling between 67% and 109% of its rated power level in one-percent increments. The RS-25 operates at temperatures ranging from −253 °C (−423 °F) to 3300 °C (6000 °F).

The Space Shuttle used a cluster of three RS-25 engines mounted in the stern structure of the orbiter, with fuel being drawn from the external tank. The engines were used for propulsion during the entirety of the spacecraft’s ascent, with additional thrust being provided by two solid rocket boosters and the orbiter’s two AJ-10 orbital maneuvering system engines. Following each flight, the RS-25 engines were removed from the orbiter, inspected, and refurbished before being reused on another mission.

Video Credit: Aerojet Rocketdyne

Wikipedia dicit:

Delta IV is a group of five expendable launch systems in the Delta rocket family introduced in the early 2000s. Originally designed by Boeing’s Defense, Space & Security division for the Evolved Expendable Launch Vehicle (EELV) program, the Delta IV became a United Launch Alliance (ULA) product in 2006. The Delta IV was and is primarily a launch vehicle for United States Air Force military payloads, but has also been used to launch a number of U.S. government non-military payloads and a single commercial satellite.

The Delta IV originally had two main versions which allowed the family to cover a range of payload sizes and masses: the retired Medium (which had four configurations) and Heavy. As of 2019, only the Heavy remains active, with payloads that would previously fly on Medium moving to either the existing Atlas V or the forthcoming Vulcan. Retirement of the Delta IV is anticipated in 2024.

Delta IV vehicles are built in the ULA facility in Decatur, Alabama. Final assembly is completed at the launch site by ULA: at the Horizontal Integration Facility for launches from SLC-37B at Cape Canaveral and in a similar facility for launches from SLC-6 at Vandenberg Air Force Base.

Video Credit: ULA