This may not end well:
A man saying he was doing research for the U.S. government called with a few polite, pointed questions: How did she build that lab? Did she know other people creating new life forms at home?
The caller said the agency he represented is “used to thinking about rogue states and threats from that,” recalls Ms. Aull, a recent Massachusetts Institute of Technology graduate.
I’ll bet they are.
Once again, scramjet proponents are touting them for space access:
Officials hope the engine eventually will provide a speedier transition between conventional aircraft in the atmosphere and rockets in outer space for deployment of satellites, and reconnaissance or strike missions.
“The long-range goal of this for the Air Force is access to space,” said Charlie Brink, an Air Force Research Laboratory propulsion directorate official who manages the X-51 program from Wright-Patterson Air Force Base.
I wonder if he’s actually done any systems studies to see whether that’s going to pan out? I have.
I’m all in favor of scramjets — they have lots of interesting and useful military applications, but it is very unlikely that they will be helpful for space access. I won’t repeat what I wrote the last time this issue came up (geez was it really five years ago?), but you can go read it here:
Proponents claim that by allowing airbreathing up to high Mach numbers, there is no need to take along as much oxygen for the rocket engines, because they can gather it for “free.” This argument assumes that space transportation is expensive because propellants are, but those aren’t the cost driver. If they were, space would already be affordable, because liquid oxygen is actually about as cheap as milk. Propellant costs are such a tiny fraction of launch costs that they’re down in the noise. If we ever get to the point where they become a real issue (as they are for airlines), we’ll have solved the problem.
Their argument also fails on the grounds that collecting oxygen isn’t really “free.” As the old joke goes, there’s no free launch.
If your space transport were to be single stage, you’d now need three propulsion systems — conventional jet, scramjet, and rocket for when you left the atmosphere (which you must do by definition to go into space). It may be possible to have a scramjet lower stage and a rocket upper stage, but the bottom line is that time spent in the atmosphere (necessary to utilize the scramjet) is time spent fighting drag, defeating the purpose. Rockets want to spend as little time as possible in the atmosphere, and carrying two other kinds of engines along and spending enough time in the air to utilize them, just to save on a propellant as cheap as oxygen, just doesn’t make design sense.
In addition, a scramjet engine is designed to operate at a specific vehicle speed, and has poor performance in “off design” conditions, rendering it a poor propulsion choice for an accelerating vehicle.
Henry Spencer debunked airbreathers to orbit earlier this year as well.
…as reviewed by one of its greatest fans (in multiple meanings of the word): Lileks. Possibly spoilers, but not a lot of plot reveals, so perhaps safe for those who haven’t seen (I haven’t).
I’ve been using sshfs to do remote editing on my web server. I create a directory with the server name as a mount point, owned by me in my home directory. I then mount with
$ sshfs -p <portnumber> <servername>: <mountpoint>
I also have the keys set up so it does so without a password prompt. It seems to work, but I only have read-only access — when I try to write a file it tells me that I don’t have permission. Also, I notice that when the file system is mounted, I get an owner and group of “1009” for the mount point. Is this normal? Does anyone have any idea what’s going on?
[Tuesday morning update]
D’oh! I just noticed that my line command wasn’t displaying properly before. It’s fixed now.
A potential new treatment for the prevention of aortic aneurysms. My maternal uncle died of one about ten years ago (it sure doesn’t seem like that long ago). This might have saved him, though probably something else might have gotten him by now.
[Sorry, link is fixed now]
With yet another national commission on the subject being formed, Dennis Wingo has some thoughts.
Jonathan Last has a piece at The Weekly Standard on the subject, with a quote from yours truly.
An interesting discussion of the transportation tradeoffs of biofuels.
Two alternate metaphors for the planet. I disagree with Lovelock that there are too many people, or that there is some magical “right” number of them. It’s all a function of technology level. And I disagree with Ward, too:
In his view, the costs and distances involved in moving outward from the solar system – or even terraforming the moon or Mars – just don’t seem worth the effort.
Obviously they don’t now. Technology advances will change that.
Occasionally, Firefox will crash (on my Fedora Core 10 box) without warning. I click on a link, and it just dies. Has anyone else experienced this?
[Thursday morning update]
Well, it just did it again, and completely out of the blue. I was just reading a page, not even clicking on anything, when it vanished without a trace.
Also, has anyone else noticed that, on startup, it runs like molasses and saturates the CPU, until one kills off npviewer?
[Bumped]