Thursday, June 24, 2004
Wednesday, June 23, 2004
I've been learning Lisp - after all, it's not as if I have anything else to do. It's very different to any other programming language I've learnt, and in a way it's very cool. I especially like the feature that the language itself can be used to modify the language, but I haven't really got to the stage where I can make use of that yet. Today I wrote a program:
(defun countdown (&rest args) (let ((target (apply #'encode-universal-time args)) (left)) (do ((finished nil)) (finished) (sleep 1) (setf left (- target (get-universal-time))) (if (< left 0) (setf finished t) (format t "~a:~a:~a~%" (floor (/ left 3600)) (floor (/ (mod left 3600) 60)) (mod left 60))))))
I've been finding ANSI Common Lisp by Paul Graham very handy (once Amazon finally decided to deliver it), and I've been using SBCL as my compiler.
Update: The history of Lisp, for anyone who's interested.
Monday, June 21, 2004
Friday, June 18, 2004
I mentioned a month or so ago that I'd been told that NASA was developing a new launcher called Magnum, and that I was going to investigate. Here's where I've got to.
Firstly, searching for the keyword "Magnum" in a space-related context brings up a lot of results referring to NASA launching a series of ELINT satellites in the late 1980s, which isn't very helpful. It's also hard to filter out references to the Colt Magnum series of pistols.
A document from 1998 provides some interesting information:
- Design is derived from that of the space-shuttle (this could be a replacement for the Shuttle-Z programme)
- Performance is 80 tonnes to ~400 km altitude LEO at 28.5° inclination
- Core is 8.4 m diameter to allow Magnum to launch from existing shuttle facilities (cost-cutting measure, I guess)
- Target cost is $1000 per kg (and if you believe that you'll believe anything)
Quite a lot of these details are corroborated by this Space.com article, which also contains some snazzy publicity imagery - including Lockheed-Martin and Boeing concept renders of what the fly-back boosters might look like.
Earliest information I've found is a set of 1997 lecture slides which, although interesting, are probably hopelessly out-of-date by now.
I've also found some comments from various people, many of which run along the lines of, "Why are we spending all this money on massive launchers so we can send spacecraft straight to Mars Apollo-style, when we could use [insert name of current, low performance launcher here] and assemble at ISS?" The fact that the ISS is in a hopeless orbit for insertion into a Martian transfer orbit, and the fact that we don't have the know-how to be able to assemble large structures in microgravity, makes this viewpoint rather an odd one.
And that's pretty much it. I've been able to find very little or no useful information dating more recently that 2000. I'm going to try e-mail MSFC directly, and see what they can tell me. It's worth a try.
Wednesday, June 16, 2004
SpaceShipOne is an Ansari X-Prize project that I've been following with great interest over the last few months. On June 21st, Scaled are going to try their first flight to the X-Prize qualifying height of 100 km, from Mojave Civilian Flight Test Center. I will be watching with great interest. If only I could be there!
Although SpaceShipOne will be going up to 100 km, Scaled still won't win the X-Prize, because the X-Prize rules stipulate that the winning craft must carry 3 people (or just a pilot and ballast equivalent to the other two crew), and the same spacecraft must trip twice in the space of 2 weeks.
Time's running out for X-Prize competitors: the prize is only available until 1st January 2005.
On a personal note, I'm not a big fan of the X-Prize. Although it seems to have succeeded to a certain extent in stimulating the development of private spaceflight, even the winning spacecraft will not be capable even of getting to orbit. The next prize would be awarded to the first private enterprise to put a man in 500 km orbit and then recover him safely, if I had any say in it. Then you've automatically got a competitive launch vehicle.
Tuesday, June 15, 2004
For the first time in my life, I'm actually revising properly for an exam. I've got Pure Maths 5 on Monday (if I remember correctly), and I've realised that although I can actually do most of the questions, I can't do them fast enough. So I'm currently hacking through the practice papers I've been given as fast as I can in the hope that I can get a reasonable mark in the exam.
Inbetween writing my blog, reading Slashdot, eating, working out on the school ergos, shooting etc, of course.
Update: Opened the fifth of my pracice papers, looked at the first question, and didn't have a clue how to do it. So I looked at the answer, and couldn't make head nor tail of it. Am currently feeling tired and depressed.
Sunday, June 13, 2004
- http://www.iqtest2.com/ - 163
- Test Cafe Detailed IQ Test - 157
- queendom.com Classical Intelligence Test - 132
- IQ Test Labs Intelligence Test - 129
Tuesday, June 08, 2004
I went to the summer members' event at the Royal Institution last night. It was a balloon debate, with four eminent scientists each taking the role of a famous director of the RI. Represented were Count Rumford (founder of the RI), Michael Faraday, Lawrence Bragg (inventor of X-ray crystallography) and George Porter (discoverer of the ozone layer hole).
I left home late, and was thus late getting to the RI (the train from Oxford being half an hour late didn't help much), but fortunately I only missed the introductory comments. Lawrence Bragg's suggestion that he hadn't actually got anything left to contribute to the world of science resulted in him being thrown out first, and George Porter got thrown out second for being too smarmy, though I thought it would have been good to have a final between George Porter and Count Rumford. Count Rumford won; although some could claim the result was rigged because Count Rumford was being played by the current director, Baronness Susan Greenfield, she was to most confident and funniest of the group.
After the debate, there were Pimm's and strawberries in the library, which was nice.
Getting home was traumatic. First I decided to wait at Paddington for a fast train to Oxford, because I didn't feel like slumming it for hours on one of the inevitable dirty and smelly local stopping trains, and so, having left the RI at half-past nine I finally left London at quarter to eleven. Then there was a points failure at Reading, so I didn't get into Oxford until quarter past midnight, whereupon I had to wait for the last bus home.
Result being that although it took me two and a half hours to get to the RI from home, it took me nearly four to get home from the RI. Understandably, this morning I feel knackered.
Saturday, June 05, 2004
On Thursday I decided to become a member of Blockbuster, so that I could rent The Return of the King and finally get to watch it.
All went swimmingly until about halfway through the battle of Pelennor Field, when there was a corrupt sector on the disc. So I took the DVD back to the branch, and got another box in return - but upon returning home, found it had two Special Features discs in it.
I took the box back on Friday afternoon, and got it exchanged, and got an extra day and a free rental for my trouble. But upon getting home late on Friday evening, I found the box had two Special Features discs in again. You can imagine how pleased I was about that.
Anyway, so today I've finally got it replaced again, and I'm looking forward to watching the rest of the movie. I might start again from the beginning now, coming to think about it.
As an aside, I'm using MPlayer to play DVDs, but sometimes it gets really stuttery and I have to reboot before it'll play the DVD smoothly. I also sometimes get "Your computer is too slow, sucker" messages as well, which are annoying. I really like the text-mode DVD playback though...
Tuesday, June 01, 2004
Traditionally at our school, the week before the summer half term (and, therefore, the school open day) is heavily disrupted by the Upper 6th fooling about. So, not being the sort of people who break an established tradition, we carried out the following atrocities.
On Monday, a number of people dressed in combats and masks ran into whole school assembly and stole the school captain.
On Wednesday, I had my last Physics lesson with Mr. H. I sauntered in 20 minutes late, wearing none of the right school uniform, swigging from a vodka bottle. I think he found it funny.
On Wednesday night, we put a clapped out little Citroen into the main hall of Norris House. Unfortunately I wasn't involved in that, because I was ill in bed. Apparently it was the first car-moving prank for about two decades, so that was good.
Thursday night was our big prank. All week, the school refectory staff had been locking up really carefully, closing all the windows and chaining up the doors. Not to ignore a good challenge, we broke in in the middle of the night, and moved all the furniture onto the school croquet lawn. Not yet satisfied, we also moved the Citroen and all the staff dining room's furniture into the refectory. Then we removed all traces of our way in, as far as was possible. We are legends.
On Friday I did some random busking, running into rooms with my violin, playing at people, and then running off. That was funny too.