Elon Musk @elonmusk Hydraulics are usually closed, but that adds mass vs short acting open systems. F9 fins only work for 4 mins. We were ~10% off.
NASA has used parachutes for rentry. Several new technologies needed to be developed and tested to facilitate successful launch and recovery of both stages of the SpaceX reusable rocket launching system. Following the completion of the third high-altitude controlled-descent test, and the completion of the third low-altitude flight of the second-generation prototype test vehicle (plus eight flights of the first-generation Grasshopper prototype flight test vehicle), SpaceX indicated that they are now able to consistently "reenter from space at hypersonic velocity, restart main engines twice, deploy landing legs and touch down at near zero velocity."
The technologies that were developed for this program, some of which are still being refined, include::
restartable ignition system for the first-stage booster Restarts are required at both supersonic velocities in the upper atmosphere—in order to decelerate the high velocity away from the launch pad and put the booster on a descent trajectory back toward the launch pad—and at high transonic velocities in the lower atmosphere—in order to slow the terminal descent and to perform a soft landing.
new attitude control technology—for the booster stage and second stage—to bring the descending rocket body through the atmosphere in a manner conducive both to non-destructive return and sufficient aerodynamic control such that the terminal phase of the landing is possible. This includes sufficient roll control authority to keep the rocket from spinning excessively as occurred on the first high-altitude flight test in September 2013, where the roll rate exceeded the capabilities of the booster attitude control system (ACS) and the fuel in the tanks "centrifuged" to the side of the tank shutting down the single engine involved in the low-altitude deceleration maneuver. The technology needs to handle the transition from the vacuum of space at hypersonic conditions, decelerating to supersonic velocities and passing through transonic buffet, before relighting one of the main-stage engines at terminal velocity.
throttleable rocket engine technology is required to reduce engine thrust because the full thrust of even a single Merlin 1D engine exceeds the weight of the nearly empty booster core.
terminal guidance and landing capability, including a vehicle control system and a control system software algorithm to be able to land a rocket with the thrust-to-weight ratio of the vehicle greater than one, with closed-loop thrust vector and throttle control
navigation sensor suite for precision landing
lightweight, deployable landing gear for the booster stage. In May 2013, the design was shown to be a nested, telescoping piston on an A-frame. The total span of the four carbon fiber/aluminum extensible landing legs is approximately 18 meters (60 ft), and they weigh less than 2,100 kilograms (4,600 lb); the deployment system uses high-pressure Helium as the working fluid.
hypersonic grid fins were added to the design beginning on the fifth ocean-descent test flight. Arranged in an "X" configuration, the grid fins control the descending rocket's lift vector to enable a much more precise landing location.
a large floating landing platform in order to test pinpoint landings prior to receiving permission from the US government to bring returning rocket stages into US airspace over land. In the event, SpaceX built the Autonomous spaceport drone ship in 2014, and intends to conduct an initial flight test and landing attempt in January 2015.
large-surface-area thermal protection system to absorb the heat load of deceleration of the second stage from orbital velocity to terminal velocity
Elon Musk @elonmusk "Grid fins worked extremely well from hypersonic velocity to subsonic, but ran out of hydraulic fluid right before landing."
"Upcoming flight already has 50% more hydraulic fluid, so should have plenty of margin for landing attempt next month."
The operation was a success but the patient died.
When I was in the military and trying to cook frozen food over a camp stove in the Arctic we used pressure cookers. It is fast and heated the food completely without burning the bottom. It is also the most energy-efficient method of cooking Now if they added the flare design to a pressure cooker they might have the best of both designs.
Underground habitats are required not only due to the radiation threat but also due to the cold temperatures. The average temperature is -55C. Surface temperatures may reach a high of about 20 C (293 K; 68 F) at noon, at the equator, and a low of about 153 C (120 K; 243 F) at the poles. Actual temperature measurements at the Viking landers' site range from 17.2 C (256.0 K; 1.0 F) to 107 C (166 K; 161 F). The warmest soil temperature on the Mars surface estimated by the Viking Orbiter was 27 C (300 K; 81 F).
Images from the Thermal Emission Imaging System (THEMIS) aboard NASA's Mars Odyssey orbiter have revealed seven possible cave entrances on the flanks of the volcano Arsia Mons. The caves, named after loved ones of their discoverers, are collectively known as the "seven sisters." Cave entrances measure from 100 m to 252 m wide and they are believed to be at least 73 m to 96 m deep. Because light does not reach the floor of most of the caves, it is possible that they extend much deeper than these lower estimates and widen below the surface. "Dena" is the only exception; its floor is visible and was measured to be 130 m deep. The interiors of these caverns may be protected from micrometeoroids, UV radiation, solar flares and high energy particles that bombard the planet's surface.
After delivering cargo to the International Space Station, the first stage of the Falcon 9 rocket used for the flight will fire its engines for the second time. The burn will allow the rocket to reenter the atmosphere in controlled flight, without breaking up and disintegrating on the way down as most booster rockets do.
After recovering the rocket from the water on Sunday, SpaceX engineers and technicians will study it to determine what it would take to refurbish such a rocket for reuse. SpaceX also has plans to recover and reuse the second stage rocket, but for now, it will recover only the first stage and its nine Merlin engines, which make up the bulk of the cost of the rocket.
They have not released the cargo manifest yet. Who knows, there might have been hundreds of millions of dollars worth of diamonds or art or cash/bearer bonds on board. They would not need more than a 5,000 ft runway to land on if they did not plan to take off again. They could even have pulled a 'Thunderball' landing on the water and then camouflaged the plane with nets. This makes as much or even more sense than many of the other theories. If they never find the plane, it will have been the perfect crime.
Christine Jorgensen in 1952 was an American who was the first person to become widely known in the United States for having sex reassignment surgery—in this case, male to female. She had served in the Army before going to Sweden for the sex change operation. I think it was Bob Hope who quiped that "Christine Jorgensen was the first guy to go abroad and come back a broad."
Sorry, never crashed.
BB10 and the Playbook OS are both based on QNX which is also in 60% of all car infotainment units. Rock solid micro kernal OS that is also used in nuclear plants and medical devices. I have used my Playbook for over two years now and it has new crashed. Apps install without having to reboot. I think many people will be pleasantly surprised with how well BB10 and QNX just works. It also sets the stage for more integration between smartphones, tablets, and car systems.
As for the update to the Playbook, Crackberry.com says that a new version of the Bridge program is in Appworld now which means that the Playbook update to BB10 could be any day now.
I am convinced that the real reason Trudeau brought the metric system to Canada was that it would be easier to add taxes to the price of gas. Prime Minister Joe Clark was defeated in part based on the fact that he proposed a 17 cent a gallon tax on gas. Trudeau came in and imposed a tax of 10 cents a litre and no body said anything. Even today the price of gas can go up 10 cents over night. I can just imagine the uproar in the US if gas rose 40 cent/gallon over night.
While Canada has been officialy metric for 40 years most people I meet still think in imperial units and I have to explain to my wife what it means when 10 cm of snow is forecast.
In the case of a Fukishima type nuclear emergency, the US military already has the most of the equipment need for a quick response such as generators, armoured vehicles, radiation monitors, airlift etc. Under 18 U.S.C. 831, the Attorney General may request that the Secretary of Defense provide emergency assistance if civilian law enforcement is inadequate to address certain types of threats involving the release of nuclear materials. Such assistance may be by any personnel under the authority of the Department of Defense, provided such assistance does not adversely affect U.S. military preparedness.
Video of Romney introducing Ryan as the next president here. Later he comes back, puts his arm around Ryan and says he has been know to make a few mistakes. Great start.
I found something similar when I was doing my psychology thesis in 1990. I found that my bilingual participants, when compared to uni-lingual participants, had a statistically significant difference in their high school leaving grades, first year university grades and on a test of general mental ability (g). At the time I thought it made sense as the same abilities you use to learn a second language (memory, language skills, cognition) are also measures that an individual needs to learn academic subjects. I did not look at creativity but problem solving is a related ability and is considered a component of g. I think Schmidt and Hunter were right when they said every measure of success is related to g.