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PB666

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Everything posted by PB666

  1. Our cement largely comes from the Hill country. Take limestone, heat it to 1000'F, it decomposes to CaO, Silicon Dioxide is made from finely ground quartz or sand. Auminum oxides are imported or can come from aluminum silicate clays. Major ingredient in the cement is denatured Limestone. In fact the Mortar brick itself, by components, sources to limestone, sand. Thats Adobe, as in when in rains, someone is giong to have to do some patchwork.
  2. ROFLMAO. Somewhere in the background stands a smiling Joseph Stalin. But the problem is the dV required for DSG is a little bit on the high side of what FH can accomplish, I also looked what FH could do if the upperstage was Methane instead of Kerolox, about 600 dV more. You get about 2/3rds of the way to orbit, provided your cryogenic engine has enough ummph to push to orbit, theres a big pay-off beyond. As for NG, SLS, and BFR . . .vaporware. I will say one thing, pouring over the chemistry of metholox and seeing how both hyrdrolox and kerolox have really been pushed in the last few years, I think they can get at least 20 more sec of ISP out of their Raptor engines if the push it.
  3. Lol, 34,000,000,000 dollars to go. Whoops that means it will take 34 more years Off-topic. KSP has released two new updates recently, 1.4.1 and the DLC . . . .an add-on thats 15 bucks or so. I just ran a launch in 1.4.1 and it was like incredible easy to get to orbit. [while you are waiting for PLs to reach their launch sites and for JWST and EM-1 to tell you about their next slip, play the updates]
  4. I know they are listening to us! Its a pretty graph, though, I like graphs.
  5. SO two PL driven delays for SX, how are they going to launch 5 sats a month at this rate.
  6. I can only imagine how much more that is going to cost, tell me they aren't going to be made of carbon-fiber. So SRBs cannot be throttled down but the F1-B and AJ1E6 can be throttled down. So it looks like the they are no longer interested in the composite construction 4-segment SRBs.
  7. They are NASA contractors, do you expect different. Well given we are spending 2 bil a year for a launch system that will not technically exist until the middle of next year, its a relative thing. My point about the STS is that we were faulting the shuttle for overruns and failures that were primarily due to contractor malfeasance and pandering to contractors from the public guidance. " From its original total cost estimate of about US$400 million, the telescope cost about US$4.7 billion by the time of its launch. " wikipedia - Hubble_Space_Telescope Then add another 2 billion dollars for the repair mission (Shuttle cost per mission 1.5billion + instrument costs) Thats in 1993 dollars. That 6.7 billion dollars then hubble would be 11.5 billion dollars if launched today. (Note these are just the cost to get the Hubble working properly, as some of you would likely correct me, the actual cost of 2006 were billions of dollars higher, but then by 2006 the hubbles optics detectors had been near completely upgrade to new instruments; IOW a few billion more for a new telescope) Value is a relative game, so to speak. It was actually cheaper to keep the Hubble running than replace it simply because its a known, people always go by paper cost, but what you have to look at is the δ$/T$ for the last project cost.(Where the change of cost from proposal to completion is divided by the final cost) If you know what the cost of a repair mission/upgrade mission is based on the last mission it easier in real time to estimate future cost than building and launching something from scratch. But eventually the hubble will reach the end of a list of potential targets, it might be capable of modification, and then after that . . .obsolete. We are not going to have 1 Hubble replacement but 2 (WFIRST, almost got cancelled but was revived last week, estimated cost is $3.2B - is essentially a telescope of the Hubble form-factor and will likely be billions higher at operation). This is what I was saying about the shuttle, its cost were high, but the cost were a known thing, if you completely change things its only exceptional contractors who won't find a way to jack things up and create all kinds of delays. The exceptional thing about JWST is that its cooling system is way superior to the Hubbles, it can see very close to the edge of the known universe at the hydrogen absortion/emmision spectrum red shifted at 50K. The Hubbles detectors were kept at around 15C (288K) which means they could theoretically detect as low as 5 microns, because the JWST mirrors and main instruments are kept at 50K they can 'see' light that is obscured by the glow of our atmosphere at that temperature. These mirrors on the JWST are larger and can see fainter objects from 600 nm to 5 micron much more clearly than anything the Hubble could see. But the mid-infrared detectors on the JWST can detect down to 27 micrometers a red shift of 270 fold of hydrogens most UV part of lyman series. Given the CMBR is Z=1089 than there are just millions of years differences between the first stars detected at Z=11 (Tbb = 3E8 years) and the matter JWST will try to detect, a small percent difference of the total age of our known Universe. The problem is that these detectors are very sensitive to temperature and the very specialized cooling system on board, if these fail for any reason the advantage of the JWST over known telescopes will be minimal (mainly resolution at high wavelength). Failures may include a faster than expected loss rate of the coolant (which has happened before) There is the claim that there is a service docking port on the JWST such that Orion could service the device if something 'failed' or needed to be repaired. The problem is Orion per flight cost are higher than the shuttles costs; and the mission to go to the JWST at L2, service it, and then return would certainly be in the billions. So we are crossing our fingers hoping the contractors are representing the risk of failure of the sensitive instruments properly. As we recall the contractor who built the Hubbles mirror did not carefully inspect their work before launch, costing an additional 2 billion dollars. So if everything works on JWST and works for its stated mission life, 8 9 billion is not too bad. It could be worse (it just got worse).
  8. They can also combine testing into other missions, so as not to completely waste an F92S. But the bigger problem is that they really don't have a relyable paying customer for D2 and they have over 120 paying customers waiting in line for F9 and FH. Right now as satellites start reaching their RTL point thats a bottleneck.
  9. SpaceX has a future and a past. During the early part of their past they were on the steep part of their learning curve, now they are past that part of the learning curve because.. . . . its in their past. How quickly they proceed in the future depends how far outside of their comfort zone they choose to proceed. For example planning to send a million people to Mars might cause some hiccups.
  10. No, it interferes, potentially, with the electronics. . . . . .and I say no, its not going to interefere with gps, unless there a super freaky solor storm. Until it wasn't
  11. You mean clay brick, you can make bricks out of just about any soil with high inorganic content with the addition of sufficient heat or lime. Hear they make bricks out of colored concrete.
  12. http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Sentinel-3/Sentinel-3B_launch_preparations_in_full_swing
  13. http://fortune.com/2018/03/26/elon-musk-spacex-falcon-9-ionosphere-hole/
  14. https://www.cnn.com/2018/03/26/asia/china-tiangong-1-intl/index.html The smallest range is March 31 to April2
  15. Hmmph, yet another Tiongang-1 thread and with politics . . . . . .should be merged.
  16. But power is the problem to get a newton of thrust at a exhaust velocity of 210000 N = 2 * 0.8 * p /210000 in essence you need 100kw per Newton, this is untenable, you would create more drag with the solar panels than thrust to get out of orbit.
  17. http://spaceworldsnews.blogspot.com/2018/03/feature-every-second-counts-to-trace.html Synchronizing the effort to explore distortions in space-time.
  18. Yes, that is correct and a point I made earlier. Normally I agree spot on with every thing Tishkoff says, but in this case, looking at the immune genes I cannot find a basis that either confirms or denies a north African versus middle Eastern admixture, in fact there is a bit of a slight bias for African, but this could be due entirely to recent backflow. From that perspective if the admixture did occur in N. Africa then there would be a stronger case for N contribution of common Eurasian immune genes (Namely 24:02 and a few others that concentrate in N.Africa and not other parts of SSA). From the Sahel to N.Africa the problem is there are more transflows than there are static elements. There are static elements but they are close to the S. edge and typically associated with groups with roots deeper in SSA. Tishkoff is mainly an expert on SSA and she is very familiar with some of the most long-term static populations in the world (of course I don't want to argue that I am an expert -or anyone else- on evolution of super equitorial Africa since humans left and spread). The manner in which Tishkoff paints the picture they admixed in SW Asia and then flow backwards in many directions into Africa and not specifically via N. Africa, In that model its easier to place these at the edge of L2/L3 expansion outward than to place them in the context of admixed back flow specifically to N.Africa and avoiding S. Africa. In a two state model where some contribution originally comes from withing Africa at the time of admixing and other parts move into SW Asia, undergo drift and then move back into Africa again, its easier to see these. Technically her model is correct, Occam's razor requires a simplification of the hypothesis to the functional lower limit of complexity. Again taking the null hypothesis I have to allow for the possibility but in modeling assume it did not occur, and this again points to very low major antigen gene transfer from N to H relative to the contributions from D to H (which appears to be apriori of 4). And there also has to be a qualification of some of the images. In terms of where this admixture occurred if in SW Asia, the models for human entry for M prefer the middle East and for N prefer S. Arabia, but N and M have very similar timings and likely entered at the same time or mixed at some later time, so there is no specification that humans went to the edge of where Neanderthals were commonly found and mixed with them, its simply uncertain. Over the broad range of uncertainty you have to also including NE Africa as a potential mixing place. The L3 and M combined (L3 is also found in India so it was also in the mix, M and N are derivatives) place a preference of initial entry on Horn of Africa (L3 modes in this region) and Arabia, but I don't think its plausible that Ns and Hs admixed in the Horn of Africa. Anyway, as i have said take it or leave it. The papers I gave you are the state of the art, there is nothing that I can add today that improves upon these. Edit: With regard to the https://www.ncbi.nlm.nih.gov/pubmed/24162011 I should point out that this is a foundation for comparing the more distilled SSA components from components of non-Africa origin. It more or less a template. later Tishkoff went on to write this paper indicating there were archaic derivative elements that mixed within Africa. https://www.ncbi.nlm.nih.gov/pubmed/26888264 Therefore it is not completely outside the bounds of tolerance that some discussion of Neanderthal admixture in Africa occur in light of what she later wrote.
  19. Yes Arago, Arago and HdlH are sources of variation. Note that Denisovans have putatively erectine sequences in their DNA (ancient mtDNA and small amounts of primative sequence not in humans or other Neandertals. When did we go back to discussing Sardinia, I was waiting to get a reference and clarify what you said earlier, still waiting.
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