Posts by BristolBachelor 2191 publicly visible posts • joined 30 Jan 2009
To be honest they also have a good return policy; to the point where we'll shop with Amazon instead of others.
Also you know the Amazon delivery price when you select the object; with many suppliers on Amazon, its impossible to know until check-out. Even ebay does better!
I would say the approximate cost of an assembled, tested PCB is off by about 4× (as in more like $200k), but i don't know this Leonardo unit.
The ceramic capacitors in question are probably type-II ceramic chip capacitors that previously could have the solder joints reflowed in case they weren't perfect. Now they have to be thrown in the bin and a new one fitted. On top of that, the qualification of the mounting and the soldering process of type-II capacitors is now done for all types of soldering (various automatic/manual) and per size and per manufacturer.
Speaking of perfect; there have been some comments about how everything should be perfect. I've seen solder joints that have been rejected, and until you see them under ×20 or ×40 magnification binocular microscope, it's impossible to see that it isn't perfect.
The UV/light sensors on the Curiosity weather station have magnets around them to minimise light blocking by ferrous dust - and it works to an extent; you see the accumulated dust around them like doughnuts! Of course not all the dust is affected by the magnets.
What's the pool for? On Earth you need one to float and swim. In microgravity, you can just do that in the air without any worries about not breathing the water and having to dry off afterwards. Also how do you keep the water where you want it?
Now relax with a Pimms or mojito, that I understand.
I've been asked to change my way of working to agile too. I'm responsible for the power systems on spacecraft. I asked how Agile helps with that? I deliver a few cards, and they launch the spacecraft. Then later I deliver a few more cards, and they launch then to orbit, and then maybe at the end the motherboard for them to plug into and the box?
I've wondered about that. Do the houses have their heating and air conditioning turned off while they are stationary too?
Although admittedly i probably thought of it here, where in summer the temperatures inside a car go above 45 within a minute of turning off the aircon, and similarly in winter when it's -15°C outside, you'd freeze not long after turning off the engine (which also turns off the suplemental heating.
In my first job, worked for Eliot Brothers/Marconi Avionics/GEC (depending on the day of the week). The entire business ran on a homebred system on ICL mainframes. I shipped ship before 2000, but going into that, they were replacing the system because ICL no longer existed, and as I understood it, even the OS would fall over once the magic year change occurred.
On the subject of stiff that just works, there was another temp program running on a digital VAX that just never needed anything done to it. Until they turned the machine off one day to move it, after working for good knows how many years. It didn't come back and no one even knew how to get the program/ data from that machine to put on another cluster. It's a problem with long projects when even the apprentices at the start of the project retire before it finishes!
The use case isn't just to shoot down your opponents sats. When the US did it, it was to stop anyone being able to look at any bits that survive after deorbiting. (I think the excuse that hydrazine would've survived re-entry to pose a problem on the ground is a bit weak).
With the emergence of sats to perform on-orbit inspection, I see the possibility of someone deciding that they don't want someone else looking at something already in orbit. Let's hope that none decides that to avoid that they want to obliterate more sats. The correct solution is send something up to de-orbit them; which also reduced reduces what is up there.
Sometimes, certain countries are very cagey about the orbits of certain objects (and deliberately don't list them on their publicly available databases), and have been known to even design systems capable of changing orbits while on "the other side of the planet" from certain observers.
No describing in detail what a bird does is just par for the course, except in the cases where you are trying to market and sell its services publicly.
The plans I've seen have about 1kW/m² on the Earth's surface, similar to what you'd get from the sun anyway. Mispointing just means you lose the power.
The antenas to receive this are very efficient, and only need to be a few dipoles spaced apart. You could have a nice flower meadow growing around them.
No, no, no. You miss understand. They are not making this statement to make you stop sending all your money to the US military complex. They are making this statement to make you send EVEN MORE.
In other news, the US is spraying champaign because one of their satellites successfully grappled an on orbit satellite, and started to control it.
The atmosphere on the moon is very thin; not enough to clay, nor enough for "air" cooling. Plus the dust is so abrasive it will eat anything worth movement.
SLAM and auto navigation and obstacle avoidance are not the problem; we were doing that 15 years ago. The moon is the problem, and nothing that isn't designed specifically for it won't survive.
My company has just replaced an ERP system. That system replaced the original one that ran on ICL Mainframes until someone realised that the ICL's wouldn't survive Y2k. The original ran on greenscreens.
The original system would still run runs around either of its two replacements if it was still with us :-(
GEC Marconi
Oh those were the days.There were circuit diagrams done by hand on drafting film, and the smell of the blueprint duplicators....
Not everything there was a failure. I have boxes still flying and still good. BOMIS (Bill Of Materials Incoice System) that ran in the ICL mainframes that were turned off for y2k still far out performs what I work with now, as did the paperless production history dossiers even running on Apricots!).
It's true that there were a few duds along the way. The done that put on so much weight it couldn't carry its own wheels, the Lidar that didn't, etc.
We did have live telemetry from Goce as it came down. The temperatures inside our unit went through the roof, but it carried on working just fine to the end.
As for Soho, I know the failure case too well. It still gives nightmares to anyone doing anything new, hoping to not suffer the same fate.
I can't remember the specifics for Solo; it was a long time ago, but I think the radiation total dose was similar to about 20 years in geostationary orbit. Then it had to work perfectly at 20°C higher than the expected highest temperature. And all of this with a reliability of something like 99.999. I had to meet the whole specification for that, but the mission could probably work with worse performance
It doesn't surprise me when it lasts longer than the initial mission life.
A redundancy of 2 working out of 3 sub-sytems is very common in space flight. It's good that everything was ok with only 2 parachutes, to cover the possible FAILURE of one. However If they are doing that this WASN'T a failure, does that mean that the system has to cope with one less in a real failure case?
Now the boffin icon, or the troll one?
"Surely he of all people would've stood to benefit from any alternative technologies they might have had"
My reading is that with this technology, they would've shot 42 people instead of only 1, but only 8 of the shot people would've actually been of interest. (Actually shooting anyone is another topic)
"getting shot of pesky meddling foreigners with their European Court of Human Rights for example is one of their goals."
All very good, but the divorce is only from the economic side of Europe (EU). The ECHR is something entirely different, and as I understand it, the rules were basically set up by the UK and particularly the Conservatives, in order to avoid the nasties seen in Nazi Germany. Funny how they now complain that the rules are limiting them from doing what they want to do (looking at you Blunket, May, Rudd, etc.)
I've always said that it's only headline having to lump in SKY with the space industry.
If we do the same calculation for mobile, adding up all the expenditure on mobiles, infrastructure etc. and then everyone's mobile bill, and then all the business "facilitated" by mobile, we probably end up with something like the GDP.
Actually, the calculation for space will look bigger next year, because it will include all the money spent on customs (eg. Sky buying all that capacity, etc, so expect the report to show a growith due to B. :-)
Copernicus is not an ESA project. It is an EU project, and so it is they who say what goes. Where ESA plays a part is that it is "sub-contracted" to manage the delivery of the complicated stuff.
And again is a bit like leaving your snooker club; your previous subscriptions helped pay for the tables, but you lose access to them after leaving :-/
If unsalted password hashes are available, then the system is not really secure; it just means you need a bigger dictionary. If you have no unsalted password hash file, you only have 3 attempts; is "password1234" one of your first attempts? What if "Sunday10" is the password, but is 4th on your list, and the account is locked out first?
I've worked in facilities where there was very strict password control (think auto generated passwords comprising 5 blocks of 3 letter syllables, changing every month, and a different one on each system). What happens is that people write their password in their logbook or underneath the keyboard.
Rad Hard means that they'll be no effect, not that it won't break. In my experience, most things will survive the radiation in space for a year without major failure. There are occasional latch ups where you have to power off quickly to prevent burnout, but they don't happen too often.
Much more likely are upsets where something gets corrupted and then you get soft failures; sort of the equivalent of running Windows and using Excel/Outlook on Earth :D Depending on the orbit and sun activity you might expect one of these a day or even more often.
It would've been interesting to read how often these occurred.
Note that this isn't the second Sentinel satellite. However, it is the 2nd Sentinel 2. There are also 2 Sentinel 1s (1A and 1B), and there is a Sentinel 3A already in orbit. Sentinel 2C is currently in manufacture as well. The Sentinel 4s are due to go up with MTG-S, so are still a few years off, and Sentinel 5 will go up even later on Metop (although they'll be a Sentinel 5-precursor to start getting data sooner). Sentinel 6 will be the new Jason in combination with the NASA.
Nope; you slow down. Imagine that you swing a weight on a string around you. As you go slower, the circles are smaller, and as you go faster, the circles are larger. It's not exactly for the same reason, but the visualisation may help.
Note that speed up and slow down here refer to the speed of the object; not the time per orbit.
I tend to think that the 1 year lifetime is to allow for really pessimistic dependability/reliability analysis. Also you look good when it lasts much longer than expected. If you sell it as a 10 year mission, but only make it to 8, you look like a failure.
Yeah, but they're now telling me too design out the TO-5 relays. There have been a number of other, erm, happenings, so someone is going off them.
As for crazy phone calls about why you want to use an LM139 compartor designed in 1960, who are you? and list every single person who will work on it, and every address the unit will ever be at, and...
I don't know many details of the Space-X system, but I read elsewhere that the error possibly came from bad GPS value or calculation. Typically, medium range docking uses a sort of Differential GPS to compute relative distance and velocity. Possibly the distance and/or velocity suddenly changed by an amount outside of expected values.
In an earlier failure report that I read for Dragon, it said that the system failed from a Single Event Effect; some particle of radiation corrupted a value or signal, causing the system to trip. Normally critical space systems are designed to be immune to these types of event.
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