highaltitude.log.20090520

[00:41] <Laurenceb> http://wiki.ukhas.org.uk/code:capdac
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[03:28] <rjharrison> Hi guys
[03:28] <rjharrison> Who makes up the evening crew
[03:29] <rjharrison> natrium42: jcoxon and I are making some headway into the client now
[03:29] <rjharrison> The server is almost there too
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[07:13] <rjharrison> Hi jcoxon
[07:14] <rjharrison> Fixed upload of data to tracker yeasterday
[07:14] <rjharrison> Not to spacenear us yet
[07:15] <jcoxon> morning
[07:15] <jcoxon> great
[07:24] Nick change: kingj -> KingJ
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[10:52] <gordonjcp> edmoore: ping
[10:52] <edmoore> g'morning
[10:59] <gordonjcp> edmoore: hi
[10:59] <edmoore> yo
[10:59] <gordonjcp> you've got your amateur licence, haven't you?
[10:59] <gordonjcp> and are in the Cambridge area?
[11:00] <gordonjcp> could you pop into #hamradio and have a chat with a guy whose nick is futfutfut about doing his foundation somewhere around there
[11:00] <gordonjcp> if it's not too much bother?
[11:00] Action: gordonjcp -> meeting
[11:00] <edmoore> ok np
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[13:48] <Laurenceb> hi
[13:49] Action: Laurenceb has been thinking about the n prize...
[13:49] <SpeedEvil> gwaaaaan
[13:50] <Laurenceb> canterbury university have a light gas gun that can reach 7.15Km/s and fits on a table top
[13:50] <SpeedEvil> and the payload mass is ?
[13:50] <Laurenceb> unfortunately it only fires 2mm diameter by 4mm long slugs
[13:50] <Laurenceb> about 50 to 100mg
[13:51] <SpeedEvil> then you've got the bitch with gun launch
[13:51] <Laurenceb> its powered by shorgun shells
[13:51] <SpeedEvil> getting anything functional out of the other end
[13:51] <Laurenceb> *shotgun
[13:51] <Laurenceb> if its on a balloon at over 40Km it might work
[13:51] <SpeedEvil> n-prize would mean at least a kick motor to circularise
[13:51] <Laurenceb> youd need a kick motor inside the payload yes
[13:51] <Futurity_> Hi
[13:52] <SpeedEvil> or a really massive payload
[13:52] <Laurenceb> and the problem is attitude
[13:52] <SpeedEvil> that too
[13:52] <Laurenceb> - you need attitude control before firing the motor
[13:53] <Laurenceb> there are mm scale solid motors with ISP>200
[13:53] <Futurity_> n-prize? Sorry new to all this, do you have a link?
[13:53] <Laurenceb> google is your friend
[13:53] <Futurity_> true
[13:54] <SpeedEvil> Laurenceb: I don't see that as a fundamental problem
[13:54] <SpeedEvil> Laurenceb: for n-prize you'vegot to be 10-20g tho
[13:54] <SpeedEvil> Which is a whole other enchilada for gun launch.
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[13:55] <SpeedEvil> 10-20g *8km/s^2 != shotgun shell energy
[13:55] <Laurenceb> yes
[13:56] <Laurenceb> and the gun mass scales badly
[13:56] <Laurenceb> I think...
[13:57] <Laurenceb> canteburys gun is very buildable
[13:57] <Laurenceb> but the scandi labs gun is huge
[13:58] <SpeedEvil> On the order of 10^6J I think
[13:58] <SpeedEvil> Or assuming an efficiency of 1%, 10^8J, or I think 100Kg of TNT
[13:59] <SpeedEvil> Of that order anyway
[13:59] <SpeedEvil> I think spin stabilised small rockets are plausible
[13:59] <Laurenceb> for gun launch?
[13:59] <SpeedEvil> no
[14:00] <SpeedEvil> Well - there is gun launch, and gun launch
[14:00] <Laurenceb> scandi labs is 100grams+ and canterbury is <100mg
[14:00] <SpeedEvil> I think you're basically not going to get a sizeable fraction of launch velocity
[14:00] <Laurenceb> but you go from table top to 80M long
[14:00] <SpeedEvil> but 2km/s at 20g payload - say - isn't _completely_ unreasonable
[14:01] <Laurenceb> not very useful
[14:01] <SpeedEvil> then again, you've just made your payload design horribly, horribly more complex
[14:01] <Laurenceb> you need at least 6Km/s at apogee
[14:01] <SpeedEvil> As stuff that will survive 100g launches is off-the-shelf
[14:01] <SpeedEvil> 100000g is basically completely custom
[14:01] <Laurenceb> potted bare die uC would do the trick
[14:02] <SpeedEvil> and your structural mass goes _way_ up
[14:02] <SpeedEvil> batteries are a bitch, testing is a bitch, ...
[14:02] <Laurenceb> when its that small it gets easier I think
[14:03] <Laurenceb> you can get cells that small
[14:03] <SpeedEvil> well - remember also that you've made it a couple of orders of magnitude worse than your normal gun-launch problem
[14:03] <SpeedEvil> maybe 3
[14:03] <SpeedEvil> as the accelleration for a given barrel length goes as v^2
[14:03] <SpeedEvil> Or similar
[14:04] <Laurenceb> of course the other option is balloon, rocket, gun
[14:04] <Laurenceb> rocket up to 200Km from 40Km
[14:04] <Laurenceb> then arcs over and fires the gun
[14:04] <Laurenceb> but you have to lift the gun which is tricky
[14:04] Action: SpeedEvil isn't seeing a compelling case for avoiding balloon -> rocket -> rocket -> rocket
[14:05] <Laurenceb> but the small guns could maybe be made quite light
[14:05] <Laurenceb> rockets are a pain
[14:05] <SpeedEvil> so can small rockets
[14:06] <Laurenceb> of course if you aim the balloon mounted light gas gun down...
[14:06] <Laurenceb> super long range sniper
[14:07] <SpeedEvil> headshot!
[14:07] <SpeedEvil> I think the CAA might have something to say about that.
[14:08] <SpeedEvil> At least until the first few heads of the CAA pass away.
[14:08] <Laurenceb> http://astro.kent.ac.uk/facilities/lgg.htm
[14:08] <SpeedEvil> more sanely
[14:09] <Laurenceb> http://astro.kent.ac.uk/images/lgg_large.PNG
[14:09] <Laurenceb> everything past the end of the table isnt needed for a balloon
[14:09] <SpeedEvil> A balloon -> rocket, with teh first stage design meaning that launch at altitude - even at worst case attitude - cannot hit the ground under power
[14:11] <Laurenceb> I want to build mayself a light gas gun tho
[14:11] <SpeedEvil> :)
[14:11] <SpeedEvil> I'm not saying that ain't cool.
[14:11] <Laurenceb> the tricky thing is the barrel
[14:12] <SpeedEvil> Just an orbital gun to launch 10g payloads is _way_ harder.
[14:12] <Laurenceb> not sure how to do that...
[14:12] <SpeedEvil> Laurenceb: microbore pipe from screwfix.
[14:12] <Laurenceb> hmm more like stainless steel
[14:12] <Laurenceb> if I could get a load of differing diameters
[14:13] <Laurenceb> then heat each one so it fits over the others
[14:13] <Laurenceb> and construct a barrel like that
[14:13] <Laurenceb> the primary stage could be made on a lathe
[14:14] <Laurenceb> but the secondary barrel is too long to easily bore out
[14:14] <Laurenceb> and for light weight youd want varying sidewall thickness
[14:15] <SpeedEvil> stainless thinwall tube liner, wound with CF
[14:15] <Laurenceb> maybe yes
[14:16] <Laurenceb> then you need a HDPE piston in front of the shell
[14:16] <Laurenceb> inside the first stage barrel with could be some heavy duty pipe
[14:18] <SpeedEvil> Remember - design of guns you want oto use once may be lots less robust
[14:18] <SpeedEvil> might be worth seeing if you could arrange a walkround of the gun, and a talk with the ops
[14:18] <Laurenceb> yeah as its in the UK
[14:19] <SpeedEvil> and you're lucky enough to be in an appropriate demographic
[14:22] <Laurenceb> I think they used spare parts from the jpl light gas guns
[14:31] <Laurenceb> hmm I wonder if the metal things stacked next to the radiator are replacement barrels
[14:31] <Laurenceb> http://astro.kent.ac.uk/images/lgg_large.PNG
[14:33] <Laurenceb> I'm guessing thats a hydrogen cylinder at the right of the image
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[14:34] <SpeedEvil> normal explosive causes rapid-onset shock in high speed of sound gas which pushes the pprojectile basically?
[14:35] <Laurenceb> yes
[14:36] <Laurenceb> shell - HDPE piston - hydrogen filled barrel - burst plate - small diameter barrel
[14:36] Action: SpeedEvil wonders if you can get h monatomic for long enough
[14:36] <Laurenceb> the primary barrel narrows towards the burst plate and deforms the piston
[14:38] <mc-> is it possible to launch multiple mg 'satellites' for the n prize?
[14:39] <Laurenceb> I dont think so
[14:39] <mc-> as long as you prove that each sat has made an orbit, I don't see why not?
[14:39] <Laurenceb> the tricky thing with a balloon bourne LGG is circularization
[14:40] <Laurenceb> and residual atmospheric drag
[14:40] <Laurenceb> you need to launch from over 40Km and have a projectile of a few hundered mg
[14:40] <Laurenceb> then circularize with a delta v of ~2Km/s
[14:40] <mc-> yes, it would need a small rocket to get to 100km, then the gun from there
[14:40] <Laurenceb> with is possible
[14:40] <Laurenceb> LGGs are heavy
[14:41] <mc-> you don't need to circularize, do you?
[14:41] <Laurenceb> if you could find a way to do attitude control of the projectile, then its possible to cirularize
[14:41] <Laurenceb> if you launch from a balloon you do
[14:43] <Laurenceb> theres some mm scale motors with isp of over 200 been demonstrated
[14:43] <mc-> if you can lift the gun to 100km, then you can point it in the right direction.
[14:43] <Laurenceb> yes
[14:43] <Laurenceb> well 200Km
[14:43] <Laurenceb> thats kind of hard
[14:43] <Laurenceb> its going to weigh around 10Kg
[14:44] <mc-> that's not too heavy, a rocksoon launched largish solid motor can lift 10kg to 100km.
[14:45] <Laurenceb> hmm
[14:45] <Laurenceb> may as well have a second stage of rocket in that case
[14:46] <mc-> if each projectile is 100mg, then need to fire the gun 190 times.
[14:47] <mc-> I think it's hard to build a 10kg rocket that goes to 7km/s
[14:47] <Laurenceb> hmm yeah
[14:47] <Laurenceb> you need attitude control as well
[14:47] <Laurenceb> wheras with a gun you just fire it at the right time
[14:47] <mc-> agreed
[14:47] <mc-> how best to detect the pellets?
[14:48] <Laurenceb> - you still have an IMU, but you could get away with fins
[14:48] <Laurenceb> led an uC
[14:48] <Laurenceb> you can get 50mg lithium cells
[14:48] <Laurenceb> with titanium case
[14:48] <mc-> if each pellet was a piece of wire, it could be detected by reflecting radar off it
[14:48] <Laurenceb> then bare die uC and led gold bonded and potted
[14:49] <Laurenceb> youd need mm wave
[14:49] <Laurenceb> rather tricky
[14:49] <Laurenceb> due to atmospheric losses ect
[14:50] <mc-> if it was a long wire, then it could reflect UHF/VHF.
[14:50] <Laurenceb> bare die uC running on an RC oscillator and potted whould survive
[14:50] <Laurenceb> yes but that would have to deploy
[14:51] <Laurenceb> guess you could have a two part projectile with a coil of wire inside
[14:51] <Laurenceb> but the acceleration could weld the two halves together
[14:52] <Laurenceb> if your firing at orbital altitude at least you dont need to worry about hypersonic dynamics
[14:52] <mc-> if it was spring wire, then it would uncoil itself after it has been fired
[14:52] <Laurenceb> sure
[14:53] <Laurenceb> if it wasnt conpletely welded together by the accel
[14:53] <mc-> it could have a coating on the wire to prevent welding
[14:54] <Laurenceb> hmm i guess it hight be possible
[14:54] <Laurenceb> with the right coil design and coatings
[14:55] <Laurenceb> you really want an autoloading gun
[14:55] <Laurenceb> so it can fire several
[14:56] <Laurenceb> what sort of motor would you use for the rockoon?
[14:56] <mc-> getting every 0.1g orbital would be a major achievement, no need to have an autoloader
[14:56] <mc-> every = even
[14:57] <mc-> solid motors are easy but expensive
[14:57] <mc-> hybrids are cheap, but more complicated
[14:57] <Laurenceb> what commercial?
[14:57] <Laurenceb> hmm yeah hybrid might be more practical
[14:58] <Laurenceb> people homebrew the propellant?
[14:58] <mc-> I thinking homebrewing fuel is illegal in the UK
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[14:59] <mc-> I gave Ed a book on building hybrids
[15:00] <mc-> they aren't too hard to build, but I don't have the time.
[15:00] <Laurenceb> hmm I'm sure I've seen people at ears with homemade hybrid fuel :P
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[15:00] <Laurenceb> but yeah it looks quite easy
[15:00] <mc-> you can make the hybrid fuel grains, but you can't make solid propellant
[15:01] <Laurenceb> nos is self pressurising
[15:01] <Laurenceb> well you can
[15:01] <Laurenceb> but not large amounts easily
[15:01] <Laurenceb> ammonium perchlorate magnesium and a polymer binder/filler
[15:02] <Laurenceb> thats what they were using in the mm scale micro thrusters anyway
[15:02] <Laurenceb> buying a ton of that is going to get tricky
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[15:03] <Laurenceb> 1 gram, not so hard
[15:03] <mc-> you can buy any amount of fuel grain for hybrids
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[15:16] <Laurenceb> mc-: it comes as rods?
[15:17] <mc-> you can buy the plastic as rods
[15:17] <Laurenceb> right
[15:17] <Laurenceb> any idea on ISP ?
[15:17] <mc-> see rattworks.net, from memory it's around 170
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[15:19] <SpeedEvil> In the UK - you may well require - legally - a fireworks factory license
[15:20] <SpeedEvil> which has stupid seperation distances
[15:20] <Laurenceb> hmm maybe for solid
[15:20] <SpeedEvil> yes
[15:20] <SpeedEvil> and as
[15:20] <Laurenceb> but hybrid is inert until fuelled
[15:20] <SpeedEvil> I read it, some hybrid
[15:20] <mc-> seen a hybrid on rattworks with a 195 ISP
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[15:20] <Laurenceb> hmm rattworks are about an order of mag too small
[15:21] <Laurenceb> having said that kmowone has tried to build a ligh light gas gun
[15:21] <Laurenceb> if you used a stainless with CF overwrap construction...
[15:22] <SpeedEvil> Pity there isn't a cheaper fibre with a comparable modulus
[15:22] <mc-> getting even a small hybrid to 100km is a big challenge
[15:22] <SpeedEvil> mc-: not so much if you start out at 20km
[15:22] <Laurenceb> those rattworks motors are way too heavy
[15:22] <mc-> nobody has done it yet
[15:22] <Laurenceb> youd have to build it from scratch
[15:23] <Laurenceb> which isnt too hard I guess
[15:23] <mc-> I think it's best to start with something you know works, and get that to 100km with a rockoon
[15:24] <SpeedEvil> even 100km with a solid is pretty trivial
[15:24] <SpeedEvil> from a baloon
[15:24] <SpeedEvil> ISP/delta-v/mass-fraction-wise anyway
[15:24] <mc-> would a rattworks I90 get to 100km starting from 20km?
[15:25] Action: SpeedEvil has mislaid his rocket sim code
[15:25] <mc-> http://www.rattworks.net/29mm_hybrid_motors.html - thrust curve + other data
[15:26] <mc-> I thought CUSF has to do lots of weight reduction so their design simmed to 100km
[15:27] <SpeedEvil> I dunno - my head is calibrated for few kilo masses - I may have misremembered
[15:27] <Laurenceb> http://www.rattworks.net/images/m900_curve.jpg
[15:29] <Laurenceb> ~1KN fopr 6 seconds
[15:30] <mc-> a rockoon launched LGG seems feasible, though still a very big project.
[15:30] <Laurenceb> might just reach 1Km/s at burnout
[15:31] <Laurenceb> its going to struggle to reach 100Km
[15:31] <mc-> 1km/s = 50km altitude (if my calcs are right)
[15:32] <Laurenceb> yes
[15:32] <Laurenceb> v^2=2as
[15:32] <Laurenceb> Weight (Initial): 3288 g
[15:32] <Laurenceb> Weight (Recovery): 2789 g
[15:33] <Laurenceb> pretty pathetic fuel mass fraction
[15:33] <SpeedEvil> My numbers are probably off - tehy were based on a stage burnout velocity of maybe 2.5km/s
[15:33] <mc-> need to go at 1265m/s to reach 80km (+20km from the balloon)
[15:33] <SpeedEvil> which was very conservative for a liquid biprop with a 60% fuel fraction
[15:33] <Laurenceb> you need more than 100Km for orbit
[15:34] <mc-> probably need 1.3km/s to allow for drag
[15:34] <Laurenceb> you should launch at 40Km
[15:34] <mc-> I think you can do a couple of orbits at 100km
[15:34] <Laurenceb> its easier to build a balloon with those spacs
[15:35] <SpeedEvil> depends on your sectional density
[15:35] <Laurenceb> than deal with the extra drag
[15:35] <mc-> I think the balloon is several times bigger to get to 40km compared to 20km.
[15:35] <SpeedEvil> IIRC some sums indicated that for a tungsten telephone pole, edge-on, it could orbit at 50Km for one or two orbits
[15:35] <Laurenceb> guess it depends on the mass
[15:35] <SpeedEvil> end-on
[15:36] <Laurenceb> for a LGG on a balloon, you want 40Km +
[15:36] <Laurenceb> for a rokoon, youve got much more mass
[15:37] <SpeedEvil> At 40Km, you're looking at of the order of a quarter of the air density as at 30Km IIRC, and well under a tenth of that at 20km
[15:37] <SpeedEvil> IIRC
[15:38] <mc-> does that mean a 40km balloon is 10X the size of a balloon at 20km?
[15:38] <SpeedEvil> yes
[15:38] <SpeedEvil> well - no
[15:38] <SpeedEvil> it means that the free lift volume you need for a 10Kg payload is 10*
[15:38] <SpeedEvil> so you need 1000m^3, not 100m^3
[15:38] <Laurenceb> not a big change
[15:38] <Laurenceb> in seam lenght
[15:38] <Laurenceb> - the big effort in assembly
[15:39] <SpeedEvil> but, you also need to haul the probably larger and heavier - per unit payload mass - balloon up
[15:39] <Laurenceb> sure
[15:39] <Laurenceb> but polythene is quite light
[15:39] <SpeedEvil> It strongly depends on what thickness of film you feel safe with, and what the size of the baloon is.
[15:39] <Laurenceb> 20um
[15:39] <SpeedEvil> larger balloons are less affected by this
[15:41] <mc-> I think it's cheaper to build a bigger rocket, just scale up the dimensions. Helium for the balloon is expensive.
[15:42] <SpeedEvil> Hydrogen
[15:42] Nick change: kingj -> KingJ
[15:42] <SpeedEvil> It's not that scary. (tm)
[15:42] <mc-> people that make laws are scared by it though
[15:42] <Laurenceb> yes
[15:43] <mc-> whereas they aren't scared by a rocket
[15:43] <Laurenceb> and they have a habit of exploding
[15:43] <Laurenceb> erm
[15:43] <Laurenceb> they are ecared of rockets
[15:43] <Laurenceb> who needs to know what gas is in your balloon :P
[15:44] <mc-> I bet the CAA would ask...
[15:44] <Laurenceb> I had them blocked by BT XD
[15:48] <Laurenceb> hmm I think with carbon fibre based construction you might get down to a 5Kg LGG firing 2mm slugs
[15:50] <mc-> it all seems feasible, but who would pay for all of this? How much would it cost, assuming labour was free?
[15:50] <Laurenceb> barrel design is tricky... stainless liners might rupture as the youngs modulus is higher than CF...
[15:50] <Laurenceb> I'm not sure how it would all pan out - might need a brass liner
[15:51] <Laurenceb> a balloon bourne LGG could be very cheap
[15:51] <Laurenceb> rockoon based LGG not so cheap
[15:52] <mc-> a rockoon itself is not expensive, and the electronics/controls are mostly software
[15:53] <gordonjcp> LGG?
[15:53] <mc-> light gas gun
[15:54] <mc-> Laurenceb is taking over the world with his LGG
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[15:55] <rjharrison> Helloooooo
[15:55] <Laurenceb> I really like the idea of orbit circularization with projectile based thrusters
[15:55] <Laurenceb> as it'd be very cheap
[15:55] <Laurenceb> you'd have to assemble it under a microscope
[15:56] <SpeedEvil> projectile thrustters hve very low isp
[15:57] <jcoxon> hey all
[15:57] <Laurenceb> >200 has been demonstrated
[15:57] <Laurenceb> hi jcoxon
[15:57] <SpeedEvil> hey
[15:58] Action: SpeedEvil is _finally_ getting over this stupid flu thing that's been destroying him for the past couple of weeks.
[15:59] <jcoxon> oooh cool a ESA british astronaunt
[15:59] <jcoxon> thats a suprise
[15:59] <SpeedEvil> yeah
[15:59] Action: SpeedEvil wouldn't recommend holding breath till ESA missions.
[16:00] <jcoxon> its a step in the right direction
[16:00] <jcoxon> perhaps the government might contribute some money now to the human flight programme thingy
[16:00] Action: Laurenceb isnt convinced
[16:00] <SpeedEvil> IMO - burn down NASA, and ESA, and you'd have a good start.
[16:01] <Laurenceb> hmm if you make a fire once LGG you can shave tons of mass of by avoiding the two couplings
[16:01] <Laurenceb> just wrap it all in CF and hope for the best :P
[16:01] <jcoxon> hi Futurity_ welcome to #highaltitude
[16:02] <SpeedEvil> elcome@
[16:02] <mc-> you only need to fire a LGG once to prove something can be orbited
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[16:02] Action: SpeedEvil sighs.
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[16:05] <Laurenceb> need to write a LGG simulator
[16:05] <mc-> edmoore, can you give some figures on Martlet, such as delta/v, weights etc?
[16:06] <edmoore> weight is <5kg
[16:06] <Laurenceb> then use a monte carlo design optimiser
[16:06] <edmoore> it's single stage, so delta v is just the max speed which is Mach5
[16:07] Action: SpeedEvil puts it all on black.
[16:07] <Laurenceb> whats the payloab?
[16:07] <jcoxon> space port :-)
[16:07] <edmoore> ?
[16:08] <Laurenceb> payload
[16:08] <jcoxon> hehe CUSFs aim is to get port into space :-)
[16:09] <edmoore> oh yes
[16:09] <edmoore> payload is almost non existant
[16:09] <edmoore> just want to get there and take pictures
[16:09] <Laurenceb> I see
[16:09] <Laurenceb> we were thinking about launching a LGG
[16:10] Action: SpeedEvil backs away from Laurenceb.
[16:10] <edmoore> LGG?
[16:11] <Laurenceb> light gas gun
[16:11] <Laurenceb> Weight (Initial): 3288 g
[16:11] <Laurenceb> oops
[16:12] <jcoxon> edmoore, you busy?
[16:12] <Laurenceb> http://ares.jsc.nasa.gov/education/websites/craters/lgg.htm
[16:13] <edmoore> afraid I'm just about to head off yes
[16:13] <jcoxon> no worries
[16:17] <Laurenceb> put on radio wales if you can hear it
[16:17] <Laurenceb> - bbc
[16:17] <mc-> what's on?
[16:19] <Laurenceb> talking about gps
[16:19] <Laurenceb> with some guys I'm working with
[16:19] <Laurenceb> actually I think its not going out live
[16:19] <Laurenceb> prob later
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[16:50] <Laurenceb> hmm there is another option - electrostatric acceleration
[17:03] <Laurenceb> http://www.iop.org/EJ/abstract/0957-0233/10/1/011
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[17:06] <edmoore> afternnn all
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[17:07] <jcoxon> hey edmoore
[17:24] <SpeedEvil> Laurenceb: 'in the range of 10^-19 to 10^-13Kg'
[17:26] <Laurenceb> http://www.bbc.co.uk/wales/
[17:26] <Laurenceb> http://www.bbc.co.uk/go/wales/hp/int/radio/ti/-/http://www.bbc.co.uk/radio/aod/wales.shtml
[17:27] <Futurity_> Hi
[17:29] <Laurenceb> lol @ the interviewer
[17:29] <Laurenceb> "thats amazing"
[17:31] <Laurenceb> SpeedEvil: yes :P
[17:33] <SpeedEvil> photon drive!
[17:34] <Laurenceb> or ram accelerator
[17:34] <Laurenceb> but thats much more expermiental
[17:34] <SpeedEvil> Interesting that the delta-v of a modern lithium-ion battery, and 50% LED isn't actually quite 0
[17:35] <Laurenceb> http://www.tbfg.org/papers/Ram%20Accelerator%20Technical%20Risks%20ISDC07.pdf
[17:36] <SpeedEvil> 200Wh/Kg = 600KJ/Kg = 300KJ of light = .1ns/Kg = .1m/s
[17:39] <jcoxon> hi Futurity_
[17:39] <Laurenceb> ram accelerators are stupidly long
[17:39] Action: SpeedEvil votes for bussard ramjet.
[17:39] <Laurenceb> http://www.hobbyspace.com/Links/LaunchPropulsion1.html
[17:56] <Laurenceb> theres steam riockets
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[18:32] <Laurenceb> cya all
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[19:01] <Laurenceb> hello
[19:03] <natrium42> ello
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[19:07] <SpeedEvil> 'llo
[19:09] <stilldavid> http://www.youtube.com/nasatelevision
[19:09] <stilldavid> 2m20s and 12m02s respectively awesome
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[19:14] <Laurenceb> nice stuff
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[20:16] <jcoxon> hey rjharrison
[20:16] <jcoxon> ping
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[20:19] <jcoxon> 30!
[20:21] <DanielRichman> :O
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[20:28] <g1zvn> 31?
[20:29] <jcoxon> thanks g1zvn
[20:29] <jcoxon> 32 + 2 bots and 2x jiffe
[20:30] <Laurenceb> 29
[20:30] Nick change: g1zvn -> mc-
[20:31] <mc-> Laurenceb how about building a RC glider using your radio modules?
[20:31] <Laurenceb> should work
[20:32] <Laurenceb> range is at least 5Km
[20:32] <mc-> Ive got an electric plane that can be a tow plane
[20:33] <Laurenceb> nice
[20:33] <mc-> any wide open space near you?
[20:33] <Laurenceb> well I'm planning to fly a module on the next balloon flight
[20:33] <Laurenceb> to get some decent range data
[20:33] <Laurenceb> theres some space on the campus
[20:34] <mc-> i need to get back in practise
[20:34] <natrium42> mc-, pcbs arrived
[20:34] <natrium42> now i need to find your cellular module
[20:34] <natrium42> :P
[20:34] <mc-> cool
[20:35] <mc-> dont worry if you cant find it
[20:35] <natrium42> well, i know where it should roughly be
[20:35] <mc-> btw do you have any gps chips spare I could try out?
[20:36] <natrium42> the venus ones, but they are altitude limited
[20:36] <natrium42> so depends on your intended usage
[20:37] <mc-> want to try them out for other stuff
[20:37] <natrium42> ok, how many do you want?
[20:37] <Laurenceb> mc-: is this you? http://www.responsivespace.com/Papers/RS1%5CSESSION6%5CCASTLE%5C6005C.ppt
[20:38] <mc-> hmm, i keep quiet about that
[20:39] <Laurenceb> ok :P
[20:39] <mc-> will tell you on a non logged channe
[20:40] <Laurenceb> 99
[20:41] <natrium42> :)
[20:42] <mc-> will go to my pc
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[21:22] <natrium42> mc-, i found the module
[21:22] <natrium42> about to go and post it
[21:23] <natrium42> included two venus chips and two pcbs for them
[21:26] <mc-> great thanks very much
[21:26] <mc-> how do the PCBs from goldp look?
[21:26] <natrium42> np
[21:26] <natrium42> great as always
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[21:27] <natrium42> waiting for some components before i can use mine
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[21:51] <Laurenceb> http://www.rocketbelts.americanrocketman.com/steam.html
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[22:13] Action: Laurenceb has his ublox-avr-um12 module setup running
[22:13] <Laurenceb> on breadboard at lest
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[22:15] <Laurenceb> any launches coming up?
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[22:44] <jcoxon> ping rjharrison
[22:50] <Laurenceb> http://www55.wolframalpha.com/input/?i=slashdot.org
[22:50] <Laurenceb> ^ interesting chart
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[23:05] <KingJ> http://www55.wolframalpha.com/input/?i=kingj.net
[23:05] <KingJ> I'm liking the page views, but it's off by an order of magnitude :P
[23:14] <jcoxon> :-)
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[23:24] <Laurenceb> http://www55.wolframalpha.com/input/?i=uk+weather
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[23:30] <SpeedEvil> http://www55.wolframalpha.com/input/?i=landing+point+of+a+balloon+ascending+at+4m%2Fs+from+glenrothes%2C+fife%2C+bursting+at+30000m%2C+and+descending+at+10m%2Fs+
[23:30] <SpeedEvil> oh well :)
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[23:42] <jcoxon> SpeedEvil, i'm sure they'll add that feature
[23:42] <Laurenceb> http://www.youtube.com/watch?v=vG5pxYv4Wp4
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[00:00] --- Thu May 21 2009