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Submission + - Elon Musk's Proposed Spaceship Can Send 100 People To Mars In 80 Days (theverge.com)

An anonymous reader writes: Today, SpaceX CEO Elon Musk unveiled the Mars vehicle — the spaceship his company plans to build to transport the first colonists to Mars. It will have a diameter of 17 meters. The plan is to send about 100 people per trip, though Musk wants to ultimately take 200 or more per flight to make the cost cheaper per person. The trip can take as little as 80 days or as many as 150 depending on the year. The hope is that the transport time will be only 30 days “in the more distant future.” The rocket booster will have a diameter of 12 meters and the stack height will be 122 meters. The spaceship should hold a cargo of up to 450 tons depending on how many refills can be done with the tanker. As rumored, the Mars vehicle will be reusable and the spaceship will refuel in orbit. The trip will work like this: First, the spaceship will launch out of Pad 39A, which is under development right now at the Kennedy Space Center at Cape Canaveral, Florida. At liftoff, the booster will have 127,800 kilonewtons of thrust, or 28,730,000 pounds of thrust. Then, the spaceship and booster separate. The spaceship heads to orbit, while the booster heads back to Earth, coming back within about 20 minutes. Back on Earth, the booster lands on a launch mount and a propellant tanker is loaded onto the booster. The entire unit — now filled with fuel — lifts off again. It joins with the spaceship, which is then refueled in orbit. The propellant tankers will go up anywhere from three to five times to fill the tanks of the spaceship. The spaceship finally departs for Mars. To make the trip more attractive for its crew members, Musk promises that it’ll be “really fun” with zero-G games, movies, cabins, games, a restaurant. Once it reaches Mars, the vehicle will land on the surface, using its rocket engines to lower itself gently down to the ground. The spaceship’s passengers will use the vehicle, as well as cargo and hardware that’s already been shipped over to Mars, to set up a long-term colony. At the rate of 20 to 50 total Mars trips, it will take anywhere from 40 to 100 years to achieve a fully self-sustaining civilization with one million people on Mars, says Musk.

Submission + - Dark matter detection to go ultra sensitive with LUX-ZEPLIN (LZ) (topexaminer.com)

hypnosec writes: The US Department of Energy has given a green light to the world’s most sensitive dark matter detector ever built — LUX-ZEPLIN (LZ). The dark matter detector, has received an approval for the scope, cost and schedule. LZ is named for the merger of two dark matter detection experiments: the Large Underground Xenon experiment (LUX) and the UK-based ZonEd Proportional scintillation in Liquid Noble gases experiment (ZEPLIN). LUX, a smaller liquid xenon-based underground experiment at SURF will be dismantled to make way for the new project.

Comment HP employee here (Score 5, Informative) 194

Well, HPE, and not for much longer (going out on my terms)... anyway - we used to get ink for free, before the split last November, but honestly, I stopped using my HP printer about a year before that. The scanner functionality didn't work right over the network and after getting a Dell (the horror) color laser, there was no reason to print on an inkjet anyway. Now I have an All-in-one that prints great color and scans, all over the network - even does AirPrint and an app to print over Android devices, too.

Regardless of my feeling toward Meg Whitman and destruction of HP, I'd still recommend never buying HP Inkjets - same as I recommend not buying Epson (had those for years, then they put in a self-destruct after 3000 prints that just printed garbage on your media, dumb and expensive to the user).

The tactics of these companies are reprehensible, and should not be supported by anybody. It's not like HP cares about its customers any more, anyway. It's all about stock prices so they can sell it all off to hedge funds (and devalue the middle class' pension funds to line their own pockets) just before it finally collapses.

Comment Re: Powerful indeed! (Score 1) 110

The F-1 was actually optimised for reliability and not-killing-the-passengers hence its abysmal performance by today's standards.

I believe GP was referring to aerostatic nozzle optimization, which every rocket needs to have. This type of optimization applies only to the nozzle, and not the rest of the rocket engine. (pumps, combustion chamber, etc.) A rocket with a nozzle designed for space will not perform well compared to the same rocket with a nozzle optimized for earth at sea level. This is because Earth's atmosphere plays a role in how the gases expand from the engine.

This phenomenon can be observed particularly well on the SpaceX webcasts. The exhaust gases from the engine are expelled directly behind the engine when the rocket is leaving the launch pad. Just before stage separation though, a significant portion of the exhaust gasses can be seen to the sides of the rocket. This is another of the many reasons multiple stages are used in rocketry.

Other trade offs are made between safety and performance, mainly in the combustion chamber and pumps. Experienced scientists and engineers can do some calculations to factor out nozzle optimization and get a more accurate comparison between different types of rockets.

Submission + - Roller Coasters Could Help People Pass Kidney Stones, Says Study (nbcnews.com)

An anonymous reader writes: Two researchers who took science to the amusement park say they've found that a thrilling roller coaster ride just might help people shake out pesky kidney stones. Dr. David Wartinger of Michigan State University said he'd heard patient after patient tell him about how they had passed kidney stones after riding one particular ride: the Big Thunder Mountain Railroad roller coaster at Walt Disney World in Orlando. He and a colleague, Dr. Marc Mitchell, had also seen some media reports about people who passed kidney stones while bungee jumping and riding roller coasters. So they decided to leave East Lansing to head to Orlando in the name of medical research. To simulate the human body as best they could, they made an artificial human kidney model out of clear silicone gel and loaded it up with real human kidney stones. They rode the roller coaster holding their kidney contraption between them in a backpack positioned at kidney height. They took 20 rides and noted what happened to each kidney stone. Riding in the back of the roller coaster train seemed to really knock the kidney stones out, they reported in The Journal of the American Osteopathic Association. "Front seating on the roller coaster resulted in a passage rate of four of 24," they wrote. "Rear seating on the roller coaster resulted in a passage rate of 23 of 36." They mainly tested the one roller coaster ride, and it's a fairly simple one. "The Big Thunder Mountain roller coaster is not a terribly dynamic ride," Wartinger said. "It's not very fast. It is not very tall. It makes sharp left and right turns that have some vibration." Wartinger suspects many different thrill rides would have the same effect. "It's not like there anything unique about this one coaster," he said. The pair have now run their test 200 more times and say the findings are consistent. Now they want to try other amusement park rides.

Submission + - Roller Coasters Can Help People Pass Kidney Stones, Says Study (nbcnews.com)

An anonymous reader writes: Two researchers who took science to the amusement park say they've found that a thrilling roller coaster ride just might help people shake out pesky kidney stonesJournal of the American Osteopathic Association. "Front seating on the roller coaster resulted in a passage rate of four of 24," they wrote. "Rear seating on the roller coaster resulted in a passage rate of 23 of 36." They mainly tested the one roller coaster ride, and it's a fairly simple one. "The Big Thunder Mountain roller coaster is not a terribly dynamic ride," Wartinger said. "It's not very fast. It is not very tall. It makes sharp left and right turns that have some vibration." Wartinger suspects many different thrill rides would have the same effect. "It's not like there anything unique about this one coaster," he said. The pair have now run their test 200 more times and say the findings are consistent. Now they want to try other amusement park rides.

Submission + - SpaceX Test Fires First Raptor Engine (techcrunch.com)

Thelasko writes: Elon Musk is preparing to unveil his plans to colonize Mars at IAC tomorrow. As a tease to his lecture, he has released some details about the Raptor engine on Twitter, including pictures.

Mr. Musk states that, "Production Raptor coal is specific impulse of 382 seconds and thrust of 3 MN (~310 metric tons) at 300 bar." He goes on to note that the specific impulse spec is at Mars ambient pressure.

Comment Re:It's missing the full picture (Score 1) 198

Ok, so you are thinking you will lose less hydrogen than the equivalent charge of a battery? You sound like you don't know anything about the issues involved.

Somehow

Power source > hydrogen > storage > fuel cell > battery

is better than

Power source > battery

in your mind? Somehow using power to crack hydrogen and store it, then run it through a fuel cell to charge a battery is infinitely more efficient than just charging the same damn battery?

Comment Re: It's missing the full picture (Score 1) 198

Do we somehow need to be to understand that H2 is not available free from any source?

H2 is produced currently by cracking natural gas (Methane), so it is a process which produces lots of CO2, and it is a process that would be better just put on the train. Wouldn't it be better to use the Methane to power the train directly? It has a higher energy content than the produced Hydrogen after all.

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