Date: 2009-07-09 15:59 Subject: Moon 40 Security: Public Tags: apollo, moon

On the 20th of this month will be the 40th anniversary of the first Moon landing, Apollo 11, famously taking Neil Armstrong and Buzz Aldrin for man’s first Moon walk.  The Lunar Excursion Module (LEM) was fundamentally a simple machine which was designed to fall to the Moon rather than fly, with one giant rocket motor underneath and some smaller attitude thrusters that allowed the spacecraft to be rotated so that the main engine could potentially point in any direction when it fired.  Control of the descent was therefore by means of a number of rocket engine “burns” that could slow the fall of the LEM.   This certainly is a “brute force” method of flying; as with Earth flying machines like a helicopter or the Harrier jet, if you have a powerful enough engine it’s possible to bludgeon the laws of physics into submission.

Later on (in the late 1970’s), the idea of landing the LEM inspired a series of popular computer games,  probably most famously the “Lunar Lander” arcade game from Atari.  I first saw versions of lunar lander in the early 1970s, running on programmable calculators, and specifically the Science of Cambridge MK14 (an early single-board microcomputer), the first computer that I ever programmed.  In the computer game, the program modelled the amount of fuel in the craft, the altitude and the speed, and of course the moon’s gravitational pull of 1.6N/kg.  By pressing a button you could “burn”, which used fuel and slowed descent.  If you studied Physics or Applied Maths at school you would have had the formulae needed to create this program, and you could even do the necessary calculations by hand.  Where the computer becomes important is in the dynamic nature of the calculations: as you burn fuel, the mass of the craft decreases, and therefore the force of the engine creates more acceleration as the flight continues. 

The real LEM had a dry weight of around 4000kg, with another 11,000kg of fuel at the start of the flight, and the descent started from a height of 15km.  Unlike the game of course, the Apollo 11 descent had two men’s lives depending on the outcome, and the flight did not go smoothly.   Armstrong famously landed the LEM (codenamed “Eagle”) with only a few seconds of fuel left in the tank, after deciding that the landing site was too rocky and deciding to fly along the surface for a while, looking for a new site.  If you’ve ever played “Lunar Lander”, you’ll know that flying along at constant height is a very expensive operation in terms of fuel, so this is a high-risk strategy.

 
The LEM also experienced some computer problems during the short flight, with the Apollo Guidance Computer giving “program alarm 1202” repeatedly, causing Armstrong to ask Mission Control whether he should abort the landing.  In subsequent analysis, the experts from MIT concluded that the computer overloaded because of the data coming from both the rendezvous radar and the ground radar at the same time.  The boffins imagined that only the ground radar would be on during the descent (to give accurate height readings), while the rendezvous radar would be used after takeoff.  Armstrong, being a test pilot, was planning for possible emergencies, and if the landing should be aborted, he wanted to be able to find “Columbia” (the command/service module) as quickly as possible as they burned away from the Moon’s surface.  You might say that the user exercised that software in the way that the programmers had not foreseen; a problem that’s still all too common in software engineering today.

I would like to think that with today’s technology it would be much easier to go to the Moon: we have faster , smaller computers;  superior materials like plastics and carbon fibre; more sophisticated fuels and engine technologies.  Certainly the one thing that hasn’t changed in the last 40 years is the courage that it would take to land on the Moon,  and we have to pay tribute to the 12 men that have done it.

Date: 2009-06-08 14:39 Subject: Burning Rubber, But Not Gas Security: Public Tags: motorcyle, race, tt, ttxgp

The Isle of Man Tourist Trophy, or “TT”, is one of the Worlds most famous and iconic motor races, where the public roads of the island are turned into a motorcycle race track.  A 38 mile (61km) course takes bikes around the island at speeds of up to 200mph (320kmh), with the fastest bikes averaging around 130mph (209kmh) over the lap.

This Friday, an important new page will open in the history of electric vehicles: the TTXGP.   The aim of the TTXGP is to build and race a zero-carbon superbike around the standard course, for two laps.  Although any zero-carbon technology is allowed, the entrants are all electric, powered by batteries; 76 miles is a long way, so clockwork or rubber-band powered is not going to be an option, and there are certain public safety issues associated with nuclear powered motorbikes, even supposing you could find a rider willing to sit on one.

Visually, the bikes look very much like petrol bikes, and in fact usually a standard road bike is the starting point for constructing the electric version.  Brakes, suspension, frame, controls are all fairly standard, but what is usually the petrol tank is now generally full of batteries.  The motors are electric, with no gearbox, and of course these vehicles are pretty much noiseless.

The electric technology looks somewhat puny in comparison with the petrol bikes, but the electric vehicles are expected to be able to reach top speeds of around 70mph.  Of course it is hoped that if this kind of racing becomes a regular fixture, then this will drive innovation in battery and motor technology.  As any engineer will tell you, you can have a hundred ideas on paper about how to build something, but the execution of building something is where the really great innovation comes from.

I’m looking forward to seeing what these bikes can do on Friday, and also hoping that this does create practical road bikes in the not-too-distant future.  An electric bike with a range of, say, 200 miles at speeds of up to 70mph seems to me like a useful vehicle for commuting.

Date: 2009-05-07 07:22 Subject: Letter to the DVD Industry Security: Public Tags: dvd, industry, movies

The DVD format is a big advance over the VHS tape, but in some ways the technology tail is being allowed to wag the entertainment dog.  Can I point out a few things to you studios and DVD producers?

1. Having different navigation on every DVD is a pain in the arse.  I know you want to make it look nice (and unique), but fundamentally I just want to select something from the menu. Mostly I just want the movie to play.  So, here are some don's for you:

- Don't redesign the cursor.  I need to know what I'm, pointing at.  Don't just use colours.  I don't know that  you think that 'red' is the cursor and 'yellow' is non-selected.
- Don't spatter the selectable icons all over the screen like a swarm of jellyfish.  Line the icons up so I know how to jump from one to the other.
- Don't play a 15 second video clip every time I come back to the menu.  I've seen it now.  The first time was enough.
- Don't add visually confusing backgrounds so that it's hard to see which is part of the menu and which not.
- Don't add extra levels of menus just because you want to make it look lke a "spaceship control panel" or some such.  Annoying.  Time-wasting.

2. Don't show me warning videos (or screens full of text) about piracy or from the FBI. I know your point of view, and I don't care.  I don't know who you think is interested in this message because:
- The real pirates have already decided to set up their duplication factories in Asia.  They will not watch you piracy video.  If we're lucky, they'll strip it off in the pirate version, and make our lives better.
- Normal home users like me are not engaged in piracy.  We don't need to be told (every time) that piracy is bad, and we don't want to watch your poxy infomercial.
- I don't believe that even if I was on the horns of the dilemma of "shall I copy and sell this DVD", that watching your trailer or reading what the FBI have to say would make any difference to me whatsoever.

Producers please note: making these parts of the disc non-skippable is not making anyone happy.  Please stop it.  Actually, this is an incitement to rip the DVD and watch it in another format: at least then we don't have to sit through unwanted rubbish.

3.  Don't show me your logos and idents.  Especially don't make these bits non-skippable.
- I don't care that you're called Warner or Sony, and I won't remember that you're asociated with this movie.
- I don't care who provided the audio technology, and I don't want to watch your promo/ident
- I don't want any of this non-skippable crap from slowing down watching the movie.

4.  Don't show me any trailers.
I realise that if I get a rental disc that it will have film trailers.  I don't want it, but I'm resigned to it.  Please note that I will skip them evey single time.  But if I buy a disc, a definitely don't want any trailers.  I bought the disc for a specific movie, and that is what I will watch repeatedly, not your ageing trailers.

Especially don't insert ads (e.g. for chocolate bars) in there too.  I do not (will not) watch commercials ona DVD disc.  If you insult me like this, then I will retaliate by not buying your confectionery.  Once again, if you fill the disc with unwanted crap, then you're playing into the hands of DVD rippers and possibly also pirates.  A format that offers the movie without all of that unwanted noise is a product that people desire.

5.  Don't show me any multi-lingual warnings after the movie has finished.  I still don't care.  Also, you know now that I speak English, because I selected that from the menu to start with.  Don't show me irrelevant rubbish when the technology allows you not to.

If you can do these simple things for me, we're going to get on fine.  Otherwise you're just making enemies and it's you that suffers in the end.  Transmission ends.