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NASA Scientists Get Custom 24h39m-per-day Watches
blair1q writes "In order to more easily keep solar time on Mars, (or maybe just as a lark) JPL has ordered specially-modified mechanical watches for the Mars Exploration Rover Mission. One wonders why these literal rocket scientists didn't just get a software programmable Linux or PalmOS based wrist-computer and hack together a Mars-time display application into it?"
Totally, completely useless. A complete waste of money.
When will they be available to the public? And how much? I want one.
Because its faster strapping on a watch that works already rather than spending a bunch of hours making the linux solution work...
The Rolax I pickup up on Market Street does that already!
Great!
:)
Now I just need a watch to keep track of that other irregular period
*duck*
And, as a layman knowing nothing about the intricacies of a 100%-mechanical wristwatch, it sounds like a frickin' impressive one.
Mad props to Mr. Anserlian!
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PGP Key ID 0xCB8FF658
Two wonder why these literal rocket scientists need to know what time it is here anyhow...
Three wonder why these literal rocket scientists don't just have really big clocks on the wall, like at the airport...
And four of us want to know why they can't just hire a booth babe to walk around and tell them what time it is... :)
"One wonders why these literal rocket scientists didn't just get a software programmable Linux or PalmOS based wrist-computer and hack together a Mars-time display application into it?"
because mechanical watches are much cooler and act as a souvenir of the project. next, why don't you go ask astronauts to trade in their mission patches for a linux box with the logo as the desktop background. don't expect to be popular with them.
Why must everything on Slashdot be Linux-based?! If they were going to make a watch on a different time system to normal then wouldnt it make more sense to just build a slightly different watch? Analogue you just add a few more teeth to the gears and digital shouldn't be too hard to alter. Putting Linux on a watch is just silly.
--Muzz
That would be a sundial right?
DROS - Open-Source Robot Software
One wonders why these literal rocket scientists didn't just get a software programmable Linux or PalmOS based wrist-computer and hack together a Mars-time display application into it?"
It is always such a relief to know that Slashdot readers know more about Astronauts should do and use than NASA engineers.
Maybe that was a bit harsh, but have you ever seen a sophisticated piece of consume electronics, such as a Palm Pilot or laptop, taken along with astronauts on their missions?
Electronics in space have to be able to handle conditions that your favorite PDA engineers did not exactly have in mind--even on an astronauts wrist. Notice that the watch is not even digital, and that if you think about it, it is probably not because the Engineers didn't read The Hitchhiker's Guide.
Computer Science is no more about computers than astronomy is about telescopes. --E. W. Dijkstra
I'll tell you why they got mechanical watches and didn't hack up a Linux watch:
1. Generally speaking digital watches are fugly. There's no Movado Digital Watch for a reason.
2. Commitment. This watch will ALWAYS run ~24h39m. You can give it to your grandkids. Your crap-ass programmable digital watch won't make it that far. Also, it can be made back into a 24h watch. There are no digital watch family heirlooms.
3. A mechanical watch is a thing of craftsmanship and beauty. A watch running Windows or Linux is cute for maybe 10 minutes then its a watch that does so many other things that they forgot the "tells time" part.
I've heard that the European Union is soon going to pass a new harmonisation order forcing everyone to adopt metric time. For the early adopters out there, it's going to be announced in exactly one month, 7 weeks, 9 days, 42 hours and 88 minutes.
while sco {
wget -O
}
it is a difficult feat of engineering. Because a mechanical watch is a combination of skill, craftmanship and beauty. Because someone said it couldn't be done. Because it is a very geeky thing to do.
Some of the mechanical watches with complications, like a perpetual calendar (keeps track of day, date and even leap year so you never have to reset the date) that has a wheel that revolves once every four years, are truly engineering marvels. Then there are tourbillons, repeaters, etc...all great feats of skill. I would buy one of these watches just for the skill involved in designing and testing it.
I would think slashdotters would understand doing something fairly "out there" just for the sake of doing it. And these are very useful. Granted useful for a small number of users, but useful nonetheless.
Now, how about a Beowulf cluster of Timex Sinclairs?
Well, if we count backwards the generations from now until the creation of Adam, I think we can safely set the 0:00:00 date to about 6,000 years ago (left as an excercise for the reader).
I'm still wondering how they will account for such things as time standing still for Joshua.
I have been pwned because my
The long version is written up here . The short version is: A handicapped friend had an unusual and extraordinary need. We met up with a master gunsmith who was so fascinated by this new challenge he'd never had before that he swept us to the head of the line despite having weeks of backlog and spent a weekend machining this unique one-off item for us. Oh and then, because "you couldn't afford to pay what this actually cost," refused to accept money for it.
We're (pretty much) all geeks here. We're all attracted to that challenge, to that thing we've never done before. I know I'm much more likely to do something for free (or at least below market rates) if it's interesting and unusual than if it's yet another damned system administration task. I know I'm not alone in our field, and my experience suggests that masters of the more mechanical arts are often similar in their attraction to the unusual job. Especially given the small number of people who'd be worthy of having such a watch, and the fact that this isn't being asked for for-profit, I would't be surprised if this guy cut them a break on it if NASA wasn't paying.
Now, with the Mars day being slightly longer than the Earth day and there are watches to match this, how do they reckon the days there? Here on Earth there is the system of Julian Days, which serves well for Earth-bound day-counting and marking dates of interesting events. This, like the UTC clock, seems to be very Earth-centric.
So are anyone contemplating a Martian calendar, or some kind of linear numbering of Mars Days, so there will be a logical date for when the various Rovers and others have landed, and other interesting events?
For all I know, such a calendar may already exist, but all I have seen of it has been various science-fiction books.
SIGBUS @ NO-07.308
It is not very impressive. In a mechanical watch is a balance wheel and a hair spring. The wheel and spring are oscilating (that is making a mechanical watch tick). The Oscilation period is the time base for the watch. You can change the oscilation period by altering the mass of the balance wheel (adding weight makes the oscilation period longer) or changing the spring constant of the hair spring (make it less stiff or langer for a longer oscilation period).
The formula for the oscillation time is
T = 2*pi*sqrt(J/k)
with
J = moment of inertia
k = the spring constant.
It looks like the watches have added weight on de balance wheel. He did a naice job but it is not earth (or mars) shattering.
Nyh
I've always thought the system proposed by (Kim Stanley Robinson) in the Mars Trilogy books was kinda neat:
All clocks stop at midnight, wait 40 minutes, then tick over to 00:01
(Yes, there are practicality and "yes, but *WHAT'S the TIME*??!?" issues, but I still reckon it'd be cool)
I found one that said Rolexxx -- ended up sitting there for a half hour arguing with the guy that since it was a fake he should sell it to me for $5...or I would continue to ruin sales (which I did as folks came by)...I got it for $7.50 (which is what the guy claimed he paid for it) to get me out of there :-)
I'll be sad the day I stop in NYC and find out the patriot act or whatever has taken these guys off the streets...*EVERYONE* knows they are fakes...a least the ones with half a brain in their head, but you gotta admit, for even $20, they make the best cheap watches you'll ever find. I'd pick one of these up over anything I could find at the local discount retailers...the fact that they blatently try to rip off the names of high society jewlery is just an added bonus.
I gave one of these as a Christmas present to a friend and TOLD him it was a fake...he claims it was one of the best gifts he'd gotten that year and enjoys it for the subversiveness of it...
Hacking a digital watch is nontrivial, especially if you have the same size and power consumption requirements as the original watch. The power budget of digital watches is austere, to say the least; typical drain of the entire watch, including oscillator, divider chain, and display driver, is 500 nA at 1.5 V, or 750 nW (a nanowatt is one billionth of a Watt).
Watches use 32.768 kHz AT-strip (tuning fork-style) quartz crystals (like these) as a compromise between size and low power consumption. The smaller the size of a crystal operating in a given mode of oscillation, the higher the frequency of oscillation. However, the power consumption of a digital switching circuit increases directly with the switching frequency (it is P (Watts) = CV^2f, where C is the capacitance of the switching device in Farads, V is the difference in volts between a logical 1 and a logical 0, and f is the frequency of switching in Hz). Having a higher oscillation frequency requires a longer frequency divider to divide the oscillator's output down to the required 1 Hz output, which raises the power consumption of the divider (mostly due to the higher switching frequency of the first few stages).
Having the crystal oscillate at a binary multiple of the desired output (32768 = 2^15) makes the divider circuits especially simple (15 divide-by-two stages in series). Having a non-binary multiple would require more switching circuitry and add to power consumption.
To hack such a system to Mars time would require either changing the crystal frequency or the divider string. Changing the divider string would require modifying the watch chip, a design task that would be relatively simple, digital design tools being what they are, but expensive and time-consuming, since a new IC mask set would have to be generated and a new lot of chips run through the fab--say, $250k and 3-6 months, if you started today. Not very desirable if you're a JPL guy funding this out of your own pocket (which is how this was done).
The alternative is to modify the crystal frequency. AT-strip tuning-fork watch crystals are cheap because they're made in a lithographic manner not dissimilar to that of IC production--a mask is made, resist is printed over a quartz blank, the blank is etched, etc. This produces nearly-identical parts in bulk, making them cheap. This is different from the standard AT-cut crystals with which most amateurs are familiar; AT-cut crystals are individually cut and polished to frequency. Since AT-strip crystals are made in bulk, one cannot get a small lot of them inexpensively, as one can AT-cut crystals; the manufacturer must make a new mask set for the new frequency, a relatively expensive task if one will only purchase, say, a hundred crystals. Modifying the crystal frequency is less expensive than making a new watch chip; however, neither option is suitable for the volumes and price points the JPL guys were trying to hit. Ergo, the mechanical watch.
--I wouldn't buy one, but understand the reasons for having them made rather than doing what the article poster suggested: ("One wonders why these literal rocket scientists didn't just get a software programmable Linux or PalmOS based wrist-computer and hack together a Mars-time display application into it?")
.2 release for the general public.
o These are collectible items available only to NASA Mars project members (for now)
o The creation of these watches took a lot of skull-sweat on the manufacturer's part and is a great accomplishment for him
o It's a team-building device
o It's a Neat Hack(TM) - RTFA.
--That said, I wonder how these watches will hold up over time (pun intended.) IANAWatch Expert but somehow I doubt the length of a Martian second is the same as ours. A more accurate way of keeping time IMHO would be to keep the length of the second the same, and add 39 minutes worth per 24h: an "extended" 12h +19:30m watch face if you like, maybe with a colored "pie slice" for the extra time period - instead of losing seconds. FTA: ( "Past the glass cases of what looks like an ordinary jewelry store is a workshop where watches are losing 39 minutes a day." )
--But like I said, *I* don't have the skill to do this in the 1st place, and maybe he will do a rev
.
== WolfriderV6 == I'm willing to admit that *I just might* be wrong... Are you??