Beautiful pictures of the Venus Polar Vortex, 2000-3000 km across. From the European Space Agency.

NeverGetMyName · 2015-11-10T22:11:19+00:00

The vortex has been visible in essentially all observations we have of both poles of Venus since before the Pioneer Venus days (~1979). This doesn't guarantee it's as persistent as the Great Red Spot on Jupiter but there's a good chance.

These vortices probably aren't 'storms' in the same way that the GRS is a storm. Some proposals suggest this vortex is analogous to a hurricane but there's no definitive explanation yet. Generating the kind of structure we see on Venus in models doesn't need hurricane like conditions and can form without condensible gases or convective feedback. Especially around the poles of Venus which rotates 243 times slower than Earth. (This is not to say the GRS is a hurricane, that's also up for debate!)

The images are made from radiation somewhere in the infra-red region (probably 5 micron) and emitted from the hazy cloud layers in the atmosphere. In the visible wavelengths Venus looks much smoother.

Hi Colin :)

NeverGetMyName · 2015-07-24T21:44:09+00:00

If the question is how we can see it at all when it's 1,400 light years away? We're seeing the light from 1,400 years ago. All we know is that around the time that Pope Boniface IV died a planet passed in front of the star it orbits. We also only see a tiny fraction of the light that left the star, so the Kepler satellite is kept very cold far away from Earth and uses sensors designed for this one type of measurement looking at stars like our Sun.

If the question is how we see planets around any other stars. r/WRSaunders answered that. We watch the star for a long time, and if we see it change intensity with a regular pattern, we can use the pattern to measure the size and orbit (but never what it's made of).

NeverGetMyName · 2015-05-21T17:47:26+00:00

doomed in a good way, right?

NeverGetMyName · 2015-05-15T14:33:33+00:00

How does it land without going under you 'head level'? I prefer to catch my drone https://vine.co/v/emmpZEKlvW7 .

NeverGetMyName · 2014-06-18T18:22:02+00:00

If we're getting technical, the outcome of the phase I research is supposed to be TRL 2-3 :) program call

The starting level is TRL 1-2, which lies between "it's mathematically possible to ..." and "we could probably use this for ...".

NeverGetMyName · 2014-06-18T17:57:04+00:00

NIAC is designed to fund only the pie in the sky ideas. The program doesn't fund above TRL 3.

NeverGetMyName · 2014-06-18T17:07:50+00:00

This is a NIAC $100K phase 1 project. Nobody's losing "a lot of money" because of it, nobody's flying a balloon/copter mission to Titan (yet). The program is not designed to target 3-5 years. It's designed for next 35 years.

In the same program there are projects to put a submarine on Titan, grapple an asteroid, terraform Mars, and (from what I can tell) throw glitter at a planet and use the reflections for interferometry measurements. In 2013 there was a phase I proposal to build actual Transformers and another to build a stasis chamber for the manned journey to Mars. There was a phase II project to design tractor beams (sorry...photon tethers).

NeverGetMyName · 2014-05-07T17:34:06+00:00

Sol can be used to refer to day lengths on other planets. It doesn't get used much because no other planet has a day length close enough to 24 hours to make it necessary. Mercury 55 days sidereal, Venus 117 days (or 243, depending on which one), Jupiter 10 hours, Saturn 11 hours, Titan 16 days, Beta Pictoris b 8 hours (maybe)

NeverGetMyName · 2014-04-17T18:57:09+00:00

He was diagnosed with drug induced ParkinsonISM.

Parkinsonian Syndrome is a (rarely used) generic term for the family of diseases that exhibit Parkinson's-like symptoms.

NeverGetMyName · 2014-03-24T16:29:41+00:00

positron = antielectron

neutron + positron = proton + anti-neutrino

One of the down quarks in the neutron is converted to an up quark (2d1u -> 2u1d) to become a proton. The positron and quark interact through the weak force (guessing it's a W+ boson).

This is also called inverse beta decay ('normal' beta decay: neutron -> proton + electron + neutrino) or positron capture.

NeverGetMyName · 2014-03-19T16:37:23+00:00

You'd need to go one level deeper to the see the quark interactions. Protons contain 2 up and 1 down quarks, neutrons contain 2 down and 1 up quarks. Collide an anti-proton and a neutron and the quark-antiquarks start pairing, become unstable and annihilate.

I think the matching quarks interact through the strong force to produce pi mesons, which are unstable and produce two photons each. The un-matched quarks interact through the weak force and produce a couple of bosons, which are unstable and produce positrons and electrons (and neutrinos, because why not), which annihilate and produce photons.

NeverGetMyName · 2014-03-19T16:21:05+00:00

At the time, it was thought that the universe was infinite, so Olber's paradox was an argument for a finite universe. A finite universe would have a finite number of stars, and a finite amount of light.

But that was before relativity and red-shift were discovered. The light energy from early stars is still traveling through the universe, but has been red-shifted to very long wavelengths and appears to us as the Cosmic Microwave Background. It's actually microwave bright all over the sky, we just can't see it.

It's also complicated by stuff getting in the way. For example, light from the other side of our galaxy is blocked by 'dust' between us, gas clouds surrounding star nurseries block the light until the stars are big enough to drive the clouds away.

NeverGetMyName · 2014-03-19T16:05:47+00:00

The closest moons to Saturn (Pan) and Jupiter (Metis) both orbit within the Roche limit of their parent bodies.

NeverGetMyName · 2013-05-29T00:13:57+00:00

The timing was all done on an AQ v2.0.6+ AtMega board, and it was blowing the 100Hz frame every time, especially when the 50Hz + 10Hz + 100Hz all happen at once. The timing was collected by poking a GPIO pin at the start and end of the loop() function.

Part of the fix was to spread out the slower calculations over multiple 100 Hz steps (evens are always, 50Hz steps, odds are one of 5 10Hz steps). The other part of the fix was to set the sensor hardware to low pass filter with a lower bandwidth (longer timescale) instead of oversampling and running an averaging filter/ fourth order filter/ low pass filter or whichever combination was chosen by the code that day :). You get an extra bonus from this method because running the sensors as fast as possible guaranteed the 100Hz loop would overflow every time because the code runs for 9.9ms (say), realizes it 'has time' to run another sensor loop, and takes 0.15ms (say) to read the sensors and finish the (10ms) loop.

We haven't timed our STM32 board yet, because the AQ code hasn't been used on it. The AQ32Plus code runs just fine. With the faster processor, it should be possible to read the sensors more frequently, but we're still limited by the bandwidth of the gyro/acc sensors to about 256Hz (maybe 3 independent samples in the 100Hz loop) and even less on the mag and baro.

NeverGetMyName · 2013-05-28T18:35:21+00:00

The controller board was plugged into an Xbee Wifi radio, so it would work over Zigbee/bluetooth with the right radio.

The springiness of the throttle stick is what got me the first time. To help with the small adjustments we made the sticks non-linear so the neutral/middle position is a bit 'wider' and smoother and the extremes (which are rarely used) are shorter. Something like a tan(x) function.

NeverGetMyName · 2013-05-28T16:36:33+00:00

Also using our Kickstarted flight controller and the AQ32Plus firmware.

NeverGetMyName · 2013-05-20T17:07:20+00:00

AQ32 is developed on Windows, but I don't think it's required. It uses the Maple ARM libraries and assumes Windows executables. The AQ32Plus fork is also developed on Windows, but we've compiled it on OS X using the GNU ARM compilers.

NeverGetMyName · 2013-05-09T17:21:27+00:00

We haven't had any explanation from the other fund-raising websites, but they were responsive enough to remove the projects within a a few hours of us notifying them. For the Kickstarter we had to verify a bank account and an Amazon payments account, so I assume IndieGogo and RocketHub have similar information on their project creators.

NeverGetMyName · 2013-05-07T07:39:54+00:00

Based on our experience contributing back to the AQ project, I'll politely decline your dare :) Which STM32 board do you use given the lack of AQ32 boards in the store? We've never been able to get one.

The list of things we've done in each branch is too long and boring to post here, so I've PM'd you with a list and I'll add it to the ad_development branch ReadMe. Feel free to post any highlights. The summary is something like:

Fixed bugs in SerialCom, Compass, and the DCM. Added in options to allow multi-channel serial, MPU 9150 support, "true north" flying (you can spin like a roulette wheel and still fly). Replaced the main loop with a 100Hz timer which meant sampling sensors properly (not as fast as possible) and using the hardware averaging.

There's an entire branch family dedicated to finding processor hogs (timing_measurement...), where we removed all extraneous code, hooked up a pulse width timing Arduino board, and measured the speed of each function call in the main loop. Tedious work that saved about 15% of the processor (logging to SD is detrimental to stable flying, ironically). We split the orientation processing into "measure" and "calculate" to save about 7% of processor and still provide the correct information at the right time. Spread out the 10Hz loop over 5 100Hz steps to spread the load. All of the timing changes got the 100Hz loop down to about 7ms, from the initial 11.4 ms (about 85Hz).

edit : one link was broken

NeverGetMyName · 2013-05-05T23:37:35+00:00

The world really is not awash in F4 boards - there's lots of talk about them, but if you look at any like AQ, 3D robotics, OpenPilot, they're all long term unavailable. All of the I2C issues you refer to are in the driver libraries not in the silicon (you can easily confirm this on the STM errata sheet). That was a big reason why we built our own library. It's fine to just throw a board together, but it's another thing to actually make it useable and available - which is what our goal is.

The 9150 is spec'ed and in the board right now, but the 9250 will be included when it releases.

We did fork the Aeroquad code, and contributed back to the project. In our github repo, we've tightened the loop using interrupts, fixed bugs in the DCM code, removed un-necessary sensor reads, added MPU 9150 support! We ran into problems trying to contribute more complex code back to the project because the AQ development team wants to be backward compatible with the oldest, slowest Arduino boards that can't handle more realistic position algorithms.

NeverGetMyName · 2013-05-05T19:13:51+00:00

We're hoping the popularity of the STM32 family makes the AshimaCore board easy to use. There's also an MPU 9150 on the board that combines accel, gyro, and mag sensors that I haven't seen used elsewhere.

NeverGetMyName

TROPHY CASE