By Soulskill from Slashdot's billy-dee-williams-volunteers-to-lead department
An anonymous reader writes: IEEE Spectrum reports on a study out of NASA exploring the idea that manned missions to Venus are possible if astronauts deploy and live in airships once they arrive. Since the atmospheric pressure at the surface is 92 times that of Earth, and the surface temperate is over 450 degrees C, the probes we've sent to Venus haven't lasted long. The Venera 8 probe sent back data for only 50 minutes after landing. Soviet missions in 1985 were able to get much more data — 46 hours worth — by suspending their probes from balloons. The new study refines that concept: "At 50 kilometers above its surface, Venus offers one atmosphere of pressure and only slightly lower gravity than Earth. Mars, in comparison, has a "sea level" atmospheric pressure of less than a hundredth of Earth's, and gravity just over a third Earth normal. The temperature at 50 km on Venus is around 75 C, which is a mere 17 degrees hotter than the highest temperature recorded on Earth.
The defining feature of these missions is the vehicle that will be doing the atmospheric exploring: a helium-filled, solar-powered airship. The robotic version would be 31 meters long (about half the size of the Goodyear blimp), while the crewed version would be nearly 130 meters long, or twice the size of a Boeing 747. The top of the airship would be covered with more than 1,000 square meters of solar panels, with a gondola slung underneath for instruments and, in the crewed version, a small habitat and the ascent vehicle that the astronauts would use to return to Venus's orbit, and home."Read Replies (0)
By Soulskill from Slashdot's good-luck department
An anonymous reader writes: SpaceX has announced that at the conclusion of its next rocket flight, it will attempt a precision landing of its Falcon 9 first stage onto an autonomous ocean platform. They say the odds of success aren't great, but it's the beginning of their work to make this a reality. Quoting: "At 14 stories tall and traveling upwards of 1300 m/s (nearly 1 mi/s), stabilizing the Falcon 9 first stage for reentry is like trying to balance a rubber broomstick on your hand in the middle of a wind storm. To help stabilize the stage and to reduce its speed, SpaceX relights the engines for a series of three burns.
The first burn—the boostback burn—adjusts the impact point of the vehicle and is followed by the supersonic retro propulsion burn that, along with the drag of the atmosphere, slows the vehicle's speed from 1300 m/s to about 250 m/s. The final burn is the landing burn, during which the legs deploy and the vehicle's speed is further reduced to around 2 m/s. ... To complicate matters further, the landing site is limited in size and not entirely stationary. The autonomous spaceport drone ship is 300 by 100 feet, with wings that extend its width to 170 feet. While that may sound huge at first, to a Falcon 9 first stage coming from space, it seems very small. The legspan of the Falcon 9 first stage is about 70 feet and while the ship is equipped with powerful thrusters to help it stay in place, it is not actually anchored, so finding the bullseye becomes particularly tricky."Read Replies (0)
By Soulskill from Slashdot's part-and-parcel department
An anonymous reader sends this quote from TechDirt:As a string of whistle blowers like former AT&T employee Mark Klein have made clear abundantly clear, the line purportedly separating intelligence operations from the nation's incumbent phone companies was all-but obliterated long ago. As such, it's relatively amusing to see Verizon announce this week that the company is offering up a new encrypted wireless voice service named Voice Cypher. Voice Cypher, Verizon states, offers "end-to-end" encryption for voice calls on iOS, Android, or BlackBerry devices equipped with a special app made by Cellcrypt.
Verizon says it's initially pitching the $45 per phone service to government agencies and corporations, but would ultimately love to offer it to consumers as a line item on your bill. Of course by "end-to-end encryption," Verizon means that the new $45 per phone service includes an embedded NSA backdoor free of charge. Apparently, in Verizon-land, "end-to-end encryption" means something entirely different than it does in the real world.Read Replies (0)
By Soulskill from Slashdot's farewell-and-thanks department
An anonymous reader writes: Dr. Dobb's — long time icon of programming magazines — "sunsets" at the end of the year. Editor Andrew Binstock says despite growing traffic numbers, the decline in revenue from ads means there will be no new content posted after 2014 ends. (The site will stay up for at least a year, hopefully longer.) Younger people may not care, but for the hard core old guys, it marks the end of a world where broad knowledge of computers and being willing to create solutions instead of reuse them was valuable.
Binstock might disagree; he said, "As our page views show, the need for an independent site with in-depth articles, code, algorithms, and reliable product reviews is still very much present. And I will dearly miss that content. I wish I could point you to another site that does similar work, but alas, I know of none."Read Replies (0)