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Comment: Re:fuel weight (Score 5, Informative) 81

by drayath (#48616459) Attached to: SpaceX To Attempt Falcon 9 Landing On Autonomous Spaceport Drone Ship

First issue is economics, fuel cost is 1-3% of launch cost. If you can only get half the payload weight to orbit but get most of your rocket back for reuse (and the first stage is the most expensive bit - 9? engines vs one for second stage), cost per Kg to orbit is still (massivly) cheaper.

Second issue is that the fuel cost for the first stage recovery is quite cheap, you only have to brake and land the engine and (almost) empty fuel tank so they are very light vs the lauch mass. From memory a while ago spaceX started using v2 of there main engine which was ~10% more efficent than the v1 engine; This gave enough increased performance that even with extra fuel to land and the extra weight from the landing legs etc. they could get the same payload to orbit plus do styage one recovery.

Comment: Re:Liquid nitrogen? (Score 3, Insightful) 127

by drayath (#32933826) Attached to: Germany To Test Actively-Cooled Spacecraft

However this is not a liquid cooling system of the tiles. The (liquid) gas is pumped through the tiles to the leading edge where it is expected to evaporate. So worst case should be no cooling from the gas or the gas layer as a protective layer between the tiles and the incoming atmosphere.

If designed properly if everything works it is re-useable, and if there is a failure you would hope a production model would be designed to that the tiles would survive a single use even without any gas flow.

PC Games (Games)

EA Shutting Down Video Game Servers Prematurely 341

Posted by Soulskill
from the sixty-dollar-yearly-fee dept.
Spacezilla writes "EA is dropping the bomb on a number of their video game servers, shutting down the online fun for many of their Xbox 360, PC and PlayStation 3 games. Not only is the inclusion of PS3 and Xbox 360 titles odd, the date the games were released is even more surprising. Yes, Madden 07 and 08 are included in the shutdown... but Madden 09 on all consoles as well?"
Earth

Yellowstone Supervolcano Larger Than First Thought 451

Posted by timothy
from the even-superer dept.
drewtheman writes "New studies of the plumbing that feeds the Yellowstone supervolcano in Wyoming's Yellowstone National Park shows the plume and the magma chamber under the volcano are larger than first thought and contradicts claims that only shallow hot rock exists. University of Utah research professor of geophysics Robert Smith led four separate studies that verify a plume of hot and molten rock at least 410 miles deep that rises at an angle from the northwest."
Games

Review Scores the "Least Important Factor" When Buying Games 169

Posted by Soulskill
from the arbitrary-numbers-are-arbitrary dept.
A recent report from a games industry analyst suggests that among a number of factors leading to the purchase of a video game — such as price, graphics and word of mouth — the game's aggregated review score is the least important measure. Analyst Doug Creutz said, "We believe that while Metacritic scores may be correlated to game quality and word of mouth, and thus somewhat predictive of title performance, they are unlikely in and of themselves to drive or undermine the success of a game. We note this, in part, because of persistent rumors that some game developers have been jawboning game reviewers into giving their games higher critical review scores. We believe the publishers are better served by spending their time on the development process than by 'grade-grubbing' after the fact."

One of the chief duties of the mathematician in acting as an advisor... is to discourage... from expecting too much from mathematics. -- N. Wiener

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