Falcon 9R failure due to faulty sensor

August 29th, 2014

Last week’s explosive failure of a Falcon 9R test rocket was due to a sensor failure in one of the engines. The test vehicle didn’t contain the multiple sensor voting system used in the commercial Falcon 9 rocket.

SpaceX founder and CEO Elon Musk said in a statement Tuesday that the cause of the prototype rocket’s demise was a “blocked sensor port.”

Garrett Reisman, who heads SpaceX’s effort to develop a private space taxi for NASA astronauts, said Wednesday that the investigation into the loss of the rocket testbed is not yet complete.

“I can tell you that it certainly looks like it was basically a single-point failure that existed on that test article that does not exist on the Falcon 9,” Reisman said. “We think it was a failure of a single sensor, and Falcon 9 has multiple sensors in its algorithm that it uses. So if the same failure occurred on the Falcon 9 it would not affect the mission in any way.”

More on Iceland – eruption started

August 28th, 2014

Update: An eruption has started. Lava is clearly visible on a webcam.

The situation in Iceland is getting worrisome. There are signs that magma is moving from the Bárðarbunga volcano to the Askja volcano. This means that both volcanoes could erupt. More information, and even more speculation, in the comments section.

More worrisome is the possibility that deep magma may be forcing its way to the surface and that could lead to a much larger rift eruption that could spew huge amounts of haze-causing aerosols into the atmosphere. When Laki erupted in 1783, the Mississippi froze all the way to New Orleans. The coming winter is likely to be as bad as last year’s – let’s hope we don’t have to deal with a huge volcanic eruption on top of that.

Complete Feynman physics lectures online

August 27th, 2014

The complete Feynman lectures on physics are now online in a multi-device friendly HTML5 format. The three volumes cover the core of physics and although some topics, like quantum physics, have advanced quite a bit since Feynman gave the original lectures in the 1960s, they are still a landmark publication. Fair warning: to really understand these, you’ll need to know some calculus and algebra – first year university level should do for most of it.

If you want to get a better idea of just how brilliant Feynman was as a teacher, you can also watch a series of lectures he gave at Cornell in 1964.

10 tips to become a Wikipedia master

August 25th, 2014

Although Wikipedia may not be a perfectly authoritative source for research, it is still an incredibly useful resource if you’re aware of its limitations. It’s also a very deep resource with many features that most people never touch. Gizmodo has published 10 tips that will help you master Wikipedia. For example, I didn’t know you could do this:

1. Create ebooks and PDFs for offline reading

Wikipedia has a built-in Book Creator tool that you can take advantage of to export content to use on other devices or when you’re offline. What better way to while away the time on a six-hour flight than with the Wikipedia entry for Dutch inventions (one of the longest articles in the database)? Or the one for your favorite sports team, television show or unsolved murder—take your pick. The Book Creator lets you combine multiple pages into one document as well.

Iceland bears watching

August 20th, 2014

It seems that one of Iceland’s major volcanoes may be getting ready to erupt. There’s been a lot of seismic activity under Bardardunga, indicating that magma is on the move. This could mean an eruption is imminent, though the scale of such an eruption is difficult to predict. A worst-case scenario isn’t likely but could be really nasty.

Icelandic authorities are taking the threat seriously:

The Icelandic Weather OfficeVeður­stofa considers it likely that there will be an eruption in Bárðarbunga and has raised the the warning stage for air traffic from yellow to orange because of this (Ed: orange is the final stage before “It’s currently erupting”). This was announce today on the noon news of RÚV, but scientists are still in a meeting with with the national protective services of the state law enforcement agency.Krist­ín Jóns­dótt­ir, a geology expert at the Weather Office, said in a conversation with RÚV that it’s the view of the scientists that magma is on the way up under the crust in two locations. The volcanic system shows continuous activity and is likely to erupt.

Update: Here’s another article from Iceland with some graphics to show the scale of the magma movement.

What’s new in DITA 1.3

August 19th, 2014

DITA keeps evolving. The DITA Technical Committee is hard at work finishing DITA 1.3, which should be finalized sometime next year. They recently presented a webinar outlining what’s new. If you don’t have the time to watch the webinar, you can view the presentation slides {PDF), which are quite detailed.