mouser.log

In lieu of actual mountain climbing this weekend... I uploaded photos from two weeks ago to my gallery. Click the image below to get to the gallery.

Posted by mouser at 4:18 PM | Permalink | Comments (0)

Plans to summit Capitol Peak this weekend have been scrapped following a pretty serious roll of my ankle last night in handball. I took a bunch of ibuprofen right after it happened and kept it on ice, but when I went to sleep the anti-inflammatories wore off and now it is swollen up like a balloon. So instead of mountain climbing, I get to spend my four day weekend sitting around the house with my ankle in a brace. Sweet.

Posted by mouser at 8:30 AM | Permalink | Comments (1)

After the HTPC's media partition took a dump last fall and I failed to fix it, the box just sort of sat there while I went about other things. I finally sat down on Wednesday evening to try and fix it again... and got it working in about 3 minutes. All it really took was

yum -y install jfsutils
fsck.jfs -p /dev/sda5

Anyway since the time of the partition bork, when Fedora Core 6 was the distro of choice... we now have Fedora 9. So I upgraded the OS last night, only to find that... when I turn on third party repositories, the network stops coming up on boot. Wha?

Posted by mouser at 9:24 AM | Permalink | Comments (1)

This is the best response ever to the people who suggest applying the Precautionary Principle to the use of the Large Hadron Collider. Be sure to read the comments (particularly #2 and #4), wherein the author of an article supporting the precautionary approach defends himself and Scott replies.

Posted by mouser at 4:13 PM | Permalink | Comments (0)

Andy and I are climbing humorously-named Mount Sneffels tomorrow. I checked weather.gov for a point forecast on the peak and got the image above, with a correspondingly useless but very detailed writeup of how nothing would be changing.

The weather appears to have been frozen in carbonite. It should be quite safe.

Nina informs me that Mt. Sneffels is actually named after a peak in Iceland, the very same peak which contains the entrance to the cave system that leads to the center of the Earth.

Posted by mouser at 9:09 AM | Permalink | Comments (1)

After 17 years, the Ulysses mission is coming to an end. The LANL-produced radio-thermal generators on board the spacecraft, featuring a little bit of cracklin' hot ²³⁸Pu, have decayed to the point that there is no longer enough electrical power on board to keep the hydrazine fuel from freezing in the pipes. Attitude control will be lost sometime in the very near future, and with it the ability to keep the antenna pointed back towards Earth.

Ulysses falls into a rare category for spacecraft—those that exceed their predicted mission lifetimes several times over. Ulysses was launched from the payload bay of Space Shuttle Discovery, back in October of 1990 with an expected mission duration of five years. I had just started high school. In February of 1992, it successfully performed a gravity slingshot around Jupiter to propel it up above the ecliptic and give it a polar orbit of the Sun-Jupiter system. Its unique vantage point has led to an abundance of data on the magnetic environment at high latitudes near the Sun, and a greater understanding of the heliosphere in general.

I am fascinated by long-mission spacecraft that go beyond low Earth orbit because of the demand for creative usage of limited resources. Once it is launched, there are no resupplies, no repairs, and no hardware upgrades. When things break, the system must be reconfigured to make the best of the remaining hardware. The US space program is replete with examples of mission teams overcoming seemingly insurmountable problems with launched hardware. Probably my favorite example is when Galileo's main antenna failed to deploy, reducing the data bandwidth from 134,000 bps to 16 bps. To combat this bottleneck in communications, mission engineers uploaded image compression algorithms that didn't exist at the time of Galileo's design, essentially causing Galileo to transmit JPEGs instead of bitmaps. This fix saved the mission, which turned out to be one of the most successful planetary science missions ever.

The Mars Exploration Rovers are certainly the most recent example of spacecraft who operate beyond their expected lifetimes. They were launched in 2003 and expected to have a 90 day operational lifetime once they arrived at Mars. After four and a half years on the surface (1584 days for Spirit), they're still cruisin' around.

But all things come to an end, and the end is very predictable for spacecraft powered by RTGs. Ulysses, though its technology is somewhat antiquated by today's standards, is still a triumph of modern science. It's achievements should be celebrated as we turn our focus to the long-mission spacecraft still out there and the upcoming missions soon to be launched.

Posted by mouser at 8:58 AM | Permalink | Comments (3)