Quote from: rockets4life97 on 10/09/2017 08:50 pmQuote from: vaporcobra on 10/09/2017 08:22 pmLooks like the North pad is progressing nicely. Not 100% certain but looks like about half of the concrete has been poured. https://www.instagram.com/p/BaCPZEWl253/?taken-by=tedwardmeyerIt looks to me like the center square has been pored and that they are poring half circle shapes around the square to make a full circle. One of these half circles (out of 4) appears to be pored. So, I'd say they are over halfway done.Agree. Looks like they poured the largest possible square that fits inside the circle and are now pouring the chord segments that complete the circle. If my memory of geometry and math and my quick calculation is correct they are actually ~73% done. Can anyone verify my math?
Quote from: vaporcobra on 10/09/2017 08:22 pmLooks like the North pad is progressing nicely. Not 100% certain but looks like about half of the concrete has been poured. https://www.instagram.com/p/BaCPZEWl253/?taken-by=tedwardmeyerIt looks to me like the center square has been pored and that they are poring half circle shapes around the square to make a full circle. One of these half circles (out of 4) appears to be pored. So, I'd say they are over halfway done.
Looks like the North pad is progressing nicely. Not 100% certain but looks like about half of the concrete has been poured. https://www.instagram.com/p/BaCPZEWl253/?taken-by=tedwardmeyer
Quote from: Kansan52 on 10/09/2017 09:15 pmAnd, if memory serves, the new landing pad will not be much larger than the 'bulls eye' of the first landing pad.The concrete areas are the same size, but the surrounding gravel ring will be smaller.
And, if memory serves, the new landing pad will not be much larger than the 'bulls eye' of the first landing pad.
Quote from: old_sellsword on 10/09/2017 09:17 pmQuote from: Kansan52 on 10/09/2017 09:15 pmAnd, if memory serves, the new landing pad will not be much larger than the 'bulls eye' of the first landing pad.The concrete areas are the same size, but the surrounding gravel ring will be smaller.Here's a site plan from February this year giving the dimensions of the new North Pad. The second drawing shows a cross-section through the pad showing some construction details (the red line on the site plan shows the location of the cross-section). Note that the pad is slightly crowned - the center is 1.25 feet higher than the outer edge of the compacted aggregate ring.
Random SpaceX numerology: The dimensions of the concrete circle seem oddly specific. The concrete pad is spec'ed as 282.84 feet in diameter. It's not an even number in metric either - 86.21 meters. It covers some odd fraction of the outer ring - 46.45%. The area is not a round number in square feet or meters. The outer ring is 415 feet exactly, so they are not averse to rounding to even values. But if you work out the size of the central square, it's exactly 200 x 200 feet. So they likely designed a square of this size, then expanded it to a circle.
Note that the pad is slightly crowned - the center is 1.25 feet higher than the outer edge of the compacted aggregate ring.
Quote from: AnalogMan on 10/10/2017 01:25 amNote that the pad is slightly crowned - the center is 1.25 feet higher than the outer edge of the compacted aggregate ring.Curvature of the Earth? They want to shed water quickly after a rain?Any ideas why they are doing that?
Quote from: Coastal Ron on 10/10/2017 06:20 pmQuote from: AnalogMan on 10/10/2017 01:25 amNote that the pad is slightly crowned - the center is 1.25 feet higher than the outer edge of the compacted aggregate ring.Curvature of the Earth? They want to shed water quickly after a rain?Any ideas why they are doing that?To avoid water puddling on the surface, undoubtedly.
The concrete needs to be kept as dry as possible. Wet concrete when quickly heated will spall and very quickly erode in the high temperature, high velocity engine exhaust.
And SpaceX is using some kind of special heat-resistant cement, I think. And a generous layer of radar-reflective paint.
http://www.sciencemag.org/news/2017/09/los-angeles-paints-streets-white-stay-cool [with photo]Los Angeles, California, in the summertime can be, for lack of a better word, a hellscape. It is the quintessential smog-laden, traffic-jammed, heat island, but a new initiative from Mayor Eric Garcetti aims to help cool the city by 1.67°C over the next 20 years. Part of the plan, Popular Science reports, is to paint over many of the city’s black roads with a reflective white coating called CoolSeal originally designed by the military to keep spy planes cool and hide them from satellite infrared cameras. Adding the coating to a patch of black asphalt can keep the area up to 5.55°C cooler, a difference that could prove vital as global temperatures continue to increase.
Quote from: Robotbeat on 10/21/2017 02:30 amAnd SpaceX is using some kind of special heat-resistant cement, I think. And a generous layer of radar-reflective paint.It doesn't seem it would matter whether or not the concrete itself is heat resistant if it's coated with reflective paint, and is radar ever aimed at the ground? *snip*