By Soulskill from Slashdot's ground-not-soft-enough department
writes: AviationWeek has posted an analysis of SpaceX's latest attempt to land its Falcon 9 rocket on an ocean barge. Quoting: "SpaceX founder and chief technology officer Elon Musk tweeted that "excess lateral velocity caused it [the booster] to tip over post landing." In a later tweet that was subsequently withdrawn, Musk then indicated that "the issue was stiction in the biprop throttle valve, resulting in control system phase lag." In this statement, Musk was referring to "stiction" — or static friction — in the valve controlling the throttling of the engine. The friction appears to have momentarily slowed the response of the engine, causing the control system to command more of an extreme reaction from the propulsion system than was required. As a result, the control system entered a form of hysteresis, a condition in which the control response lags behind changes in the effect causing it.
Despite the failure of the latest attempt, SpaceX will be encouraged by the landing accuracy of the Falcon 9 and the bigger-picture success of its guidance, navigation and control (GNC) system in bringing the booster back to the drone ship. The GNC also worked as designed during the prior landing attempt in January, which ended in the destruction of the vehicle following a hard touchdown on the edge of the platform."
In related news, SpaceX is hoping to attempt its next landing on solid ground
.Read Replies (0)
By Roblimo from Slashdot's robot-drones-want-you-to-take-them-to-your-leader-(beep) department
This is an interview with Clay McClure
. He makes his living designing 'custom Linux software solutions for technology start-ups in Atlanta and the San Francisco Bay area.' He also works on Embedded Linux for autonomous drones
. Here's a link to slides from a talk he gave on exactly that topic: Flying Penguins - Embedded Linux Applications for autonomous UAVs
, and that's far from all he has to say about making Linux-controlled drones. However, for some reason Timothy and Clay didn't talk about using drones for target practice.
Perhaps they can discuss that another time.NOTE: We urge you to read the transcript of this interview even if you prefer watching videos; it contains material we left out of the video due to sound problems.Read Replies (0)
By Soulskill from Slashdot's take-that,-mercury department
writes: NASA's MESSENGER spacecraft is in the final days of an unprecedented and unexpectedly long-lived, close-up study of the innermost planet of the solar system, with a crashing finale expected in two weeks. Out of fuel, the robotic Mercury Surface, Space Environment, Geochemistry and Ranging, or MESSENGER, probe on April 30 will succumb to the gravitational pull of this strange world that has been its home since March 2011. The purpose of the mission, originally designed to last one year, is to collect detailed geochemical and other data that will help scientists piece together of how Mercury formed and evolved. "MESSENGER is going to create a new crater on Mercury sometime in the near future ... let's not be sad about that," NASA associate administrator John Grunsfeld said Thursday.
The Johns Hopkins Applied Physics Laboratory has an excellent site for looking through the pictures MESSENGER has taken
and the science it's done.Read Replies (0)
By Soulskill from Slashdot's unexpected-alliances department
writes: Microsoft and Cyanogen Inc have announced a partnership to bring Microsoft applications to Cyanogen OS. "Under the partnership, Cyanogen will integrate and distribute Microsoft's consumer apps and services across core categories, including productivity, messaging, utilities, and cloud-based services. As part of this collaboration, Microsoft will create native integrations on Cyanogen OS, enabling a powerful new class of experiences." Ars Technica comments, "If Cyanogen really wants to ship a Googleless Android, it will need to provide alternatives to Google's services, and this Microsoft deal is a small start. Microsoft can provide alternatives for Search (Bing), Google Drive (OneDrive and Office), and Gmail (Outlook). The real missing pieces are alternatives to Google Play, Google Maps, and Google Play Services."
Rather than distribute more proprietary services, how about ownCloud for Drive, K-9 Mail for Gmail, OsmAnd for Maps, and F-Droid for an app store? Mozilla and DuckDuckGo provide Free Software search providers for Android, too. With Google neglecting the Android Open Source Project and Cyanogen partnering with Microsoft, the future for Free Software Android as anything but a shell for proprietary software looks bleak.Read Replies (0)
By Soulskill from Slashdot's good-luck-with-that department
sends news that Los Angeles Unified School District is asking Apple for a refund of the district's effort to equip students with iPads
. The project was budgeted at around $1.3 billion to equip its 650,000 students, though only about 120,000 iPads have been purchased so far. After the program went bad, the FBI launched an investigation
into their procurement practices. The iPads weren't standalone education devices — they were supposed to work in conjunction with another device carrying curriculum from a company named Pearson. But the district now says the combined tech didn't meet their needs, and they want their money back
. Lawyers for the local Board of Education are looking into litigation options. They've also notified Apple and Pearson they won't pay for any new products or services.Read Replies (0)
By timothy from Slashdot's not-all-discrimination-is-invidious department
writes An IT worker is accusing Tata Consultancy Services (TCS) of discriminating against American workers and favoring "South Asians" in hiring and promotion. It's backing up its complaint, in part, with numbers. The lawsuit, filed this week in federal court in San Francisco, claims that 95% of the 14,000 people Tata employs in the U.S. are South Asian or mostly Indian. It says this practice has created a "grossly disproportionate workforce." India-based Tata achieves its "discriminatory goals" in at least three ways, the lawsuit alleges. First, the company hires large numbers of H-1B workers. Over from 2011 to 2013, Tata sponsored nearly 21,000 new H-1B visas, all primarily Indian workers, according to the lawsuit's count. Second, when Tata hires locally, "such persons are still disproportionately South Asian," and, third, for the "relatively few non-South Asians workers that Tata hires," it disfavors them in placement, promotion and termination decisions.Read Replies (0)
By timothy from Slashdot's nothing-beats-mapblast's-vector-directions department
New submitter Robertgilberts
writes with word that Google is dropping the old version of Maps
. The new version of Google Maps came out of preview back in February 2014 and was in beta for several months before that. The only way to access the old version of Google Maps was via a special URL or if you had a very old browser that did not support the new version of Google Maps.
Consolation prize: There will still be a lighter-weight version, which "drops out many of the neat Google Maps features in exchange for speed and compatibility."Read Replies (0)