Atlas uses its whole body — legs, arms, torso — to perform a sequence of dynamic maneuvers that form a gymnastic routine. We created the maneuvers using new techniques that streamline the development process. First, an optimization algorithm transforms high-level descriptions of each maneuver into dynamically-feasible reference motions. Then Atlas tracks the motions using a model predictive controller that smoothly blends from one maneuver to the next. Using this approach, we developed the routine significantly faster than previous Atlas routines, with a performance success rate of about 80%.
Arctic sea ice likely reached its 2019 minimum extent of 1.60 million square miles (4.15 million square kilometers) on Sept. 18, tied for second lowest summertime extent in the satellite record, according to NASA and the National Snow and Ice Data Center.
The Arctic sea ice cap is an expanse of frozen seawater floating on top of the Arctic Ocean and neighboring seas. Every year, it expands and thickens during the fall and winter and grows smaller and thinner during the spring and summer. But in the past decades, increasing temperatures have caused marked decreases in the Arctic sea ice extents in all seasons, with particularly rapid reductions in the minimum end-of-summer ice extent. The shrinking of the Arctic sea ice cover can ultimately affect local ecosystems, global weather patterns, and the circulation of the oceans.
Video Credit: NASA Goddard/Lead Producer: Katie Jepson (USRA); Technical Support: Aaron E. Lepsch (ADNET); Scientists: Nathan T. Kurtz (NASA/GSFC), Walt Meier (NASA/GSFC); Lead Visualizers: Trent L. Schindler (USRA), Cindy Starr (GST); Lead Animator: Bailee DesRocher (USRA); Narrator: LK Ward (USRA); Visualizer: Lori Perkins (NASA/GSFC); Lead Writer: Maria-Jose Vinas Garcia (Telophase); Videographers: Kate Ramsayer (Telophase), Jefferson Beck (USRA), John Caldwell (AIMM)
NASA astronaut Jessica Meir, Oleg Skripochka of the Russian space agency Roscosmos, and Hazzaa Ali Almansoori from the United Arab Emirates (UAE) launched safely for their mission aboard the International Space Station on the Soyuz MS-15 spacecraft at 9:57 a.m. EDT. [September 25, 2019]
The crew began their six-hour trip to the orbital laboratory during which they will orbit Earth four times.
The SpaceX CrewDragon spacecraft parachutes successfully deploy during the latest development test. This test simulated a pad abort, where the vehicle is tumbling at low altitude before parachute deploy, validating SpaceX’s parachute models and margins. As a part of NASA’s Commercial Crew Program, SpaceX has been developing and testing the Crew Dragon parachute system, which is comprised of two drogue parachutes and four main ring-sail parachutes—the same type of parachutes that have been commonly and successfully used for human spaceflight in the past.
A reaction control system (RCS) is a spacecraft system that uses thrusters to provide attitude control, and sometimes translation. Use of diverted engine thrust to provide stable attitude control of a short-or-vertical takeoff and landing aircraft below conventional winged flight speeds, such as with the Harrier “jump jet”, may also be referred to as a reaction control system.
An RCS is capable of providing small amounts of thrust in any desired direction or combination of directions. An RCS is also capable of providing torque to allow control of rotation (roll, pitch, and yaw).
Reaction control systems often use combinations of large and small (vernier) thrusters, to allow different levels of response. Spacecraft reaction control systems are used for: attitude control during re-entry, stationkeeping in orbit, close maneuvering during docking procedures, control of orientation, or ‘pointing the nose’ of the craft, a backup means of deorbiting, ullage motors to prime the fuel system for a main engine burn.
Because spacecraft only contain a finite amount of fuel and there is little chance to refill them, alternative reaction control systems have been developed so that fuel can be conserved. For stationkeeping, some spacecraft (particularly those in geosynchronous orbit) use high-specific impulse engines such as arcjets, ion thrusters, or Hall effect thrusters. To control orientation, a few spacecraft, including the ISS, use momentum wheels which spin to control rotational rates on the vehicle.
Wherever there are humans, there are microbes, too. Bacteria and fungi live all around us, in our homes, offices, industrial areas, the outdoors – even in space. People literally could not live without these tiny organisms, many of which are beneficial.
The trick is limiting the number of potentially harmful ones, particularly in a contained environment such as a spacecraft. So from the launch of the very first module of the International Space Station, NASA has monitored its microbial community.
Because the station is an enclosed system, the only way that microbes get there is hitching a ride on the contents of resupply spacecraft from Earth and on arriving astronauts. The NASA Johnson Space Center Microbiology Laboratory puts a lot of effort into knowing which microbes ride along.
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