tag:blogger.com,1999:blog-5572744113321145124.post7337084033890504971..comments2023-07-12T08:49:11.109-05:00Comments on Radical Moderation: Some Thoughts About StarlinkTheRadicalModeratehttp://www.blogger.com/profile/04671143818738683349noreply@blogger.comBlogger7125tag:blogger.com,1999:blog-5572744113321145124.post-39238219727118496922018-12-23T00:10:38.363-06:002018-12-23T00:10:38.363-06:00Thanks, this is much closer to what I was expectin...Thanks, this is much closer to what I was expecting.<br /><br />It is also worth noting the the $10M per launch cost of the BFR/BFS assumes a LOT of reuses of both vehicles. The Space Review article on the 2017 model assumes $350M for one each of BFR/BFS (http://www.thespacereview.com/article/3343/1).Anonymoushttps://www.blogger.com/profile/02646427402872441488noreply@blogger.comtag:blogger.com,1999:blog-5572744113321145124.post-78181851044997954012018-12-22T23:54:16.426-06:002018-12-22T23:54:16.426-06:00John--
To be honest, I'm not sure where the B...John--<br /><br />To be honest, I'm not sure where the BFR number I cited came from.<br /><br />I did some analysis a while back on the Adelaide version of the BFR/BFS, in terms of getting it to the lunar and surface and back with no refueling. I think I eyeballed the results and dropped a decimal--they're quite a bit higher than the $1000 I stated. Assuming that the cargo launch refuels first in LEO, then also in HEEO (+2500 m/s delta-v), from a tanker that it itself has been refueled in LEO before rendezvousing in HEEO, and assuming $10M per launch, I get the following:<br /><br />15 launches total: 10,000 kg/launch ($15,000/kg)<br />14: 9800 kg/launch ($14,300/kg)<br />13: 8500 kg/launch ($15,300/kg)<br />12: 7100 kg/launch ($16,900/kg)<br />...<br />9: Minimum possible, at only 700 kg/launch ($128,600/kg)<br /><br />Note that this would be considerably worse with the DearMoon version of the BFR/BFS. But they're massively better if you have refueling capability on the lunar surface, or even in LLO.<br /><br />I inferred the FH mass to the surface from the <a href="https://www.thenewatlantis.com/publications/moon-direct" rel="nofollow">Zubrin Moon Direct phase 1 numbers</a>, and again my math is a bit off, although not by nearly as much: I get $14,900/kg, instead of $12,000/kg.<br /><br />But these are not apples-to-apples comparisons, since Zubrin's looking at an expendable lander and we should assume that BFRs are to expensive to expend. Zubrin also has some numbers for the BFR, but they assume a methalox lander deployed in LEO or LLO. Those come out to 20.1 t and 82.7, respectively. I frankly don't understand these: I get a number closer to 40 t deploying from LEO, and I can't get LLO to work at all without refueling. (Perhaps he's assuming an expendable BFR, which ain't gonna happen...) However, note that 40 t from LEO to the surface comes out to only $250/kg with one $10M BFR launch.<br /><br />So you have a lot of things to choose from here. By the far the best case is to build a big, honkin', expendable, methalox lander for the BFR and deploy it from LEO, but there may be some optimum that's better than this.<br /><br />Anyway, thanks for the note. I'll make a note in the text that what I have is wrong, or at least needs more work.TheRadicalModeratehttps://www.blogger.com/profile/04671143818738683349noreply@blogger.comtag:blogger.com,1999:blog-5572744113321145124.post-42895958157562407072018-12-21T12:48:39.464-06:002018-12-21T12:48:39.464-06:00TRM. Great article. I like your financial analys...TRM. Great article. I like your financial analyses, but I wonder if you might take a deeper dive into BFS/BFR costs to NEOs. I find the number of $1000/kg to lunar surface challenging to meet due to the number of on-orbit refuelling missions it will take to achieve such a trip - even one way.Anonymoushttps://www.blogger.com/profile/02646427402872441488noreply@blogger.comtag:blogger.com,1999:blog-5572744113321145124.post-6516724999000499252018-12-17T00:19:55.829-06:002018-12-17T00:19:55.829-06:00The problem with going elsewhere is that SpaceX st...The problem with going elsewhere is that SpaceX still has to build a pad. The other problem is that all SpaceX launchers are restricted by ITAR, the regulations that control export of technologies deemed to have national security implications.<br /><br />I could see them going after a pad on Wallops, but I doubt that a range sitting right next to the mouth of the Chesapeake is going to have the kind of capacity they need. There have been some speculations about doing something in Puerto Rico, but there's no infrastructure to speak of--it would be like spinning up Boca Chica all over again, but with terrible logistics.TheRadicalModeratehttps://www.blogger.com/profile/04671143818738683349noreply@blogger.comtag:blogger.com,1999:blog-5572744113321145124.post-78069491440560197252018-12-16T23:42:05.384-06:002018-12-16T23:42:05.384-06:00TRM, great write up. I wonder if SpaceX might seek...TRM, great write up. I wonder if SpaceX might seek launches at other facilities, for example the European, Japanese or New Zealand ranges. Doing so might take some pressure off the Texas range and BFR plans. Of course there would be added costs to use them. Your thoughts?Anonymoushttps://www.blogger.com/profile/05426715185950622240noreply@blogger.comtag:blogger.com,1999:blog-5572744113321145124.post-42993855806223491352018-12-16T14:24:35.233-06:002018-12-16T14:24:35.233-06:00Boeing's constellation is stalled and hasn'...Boeing's constellation is stalled and hasn't yet been approved by the FCC. OneWeb has recently scaled back their constellation from 900 birds to 600 birds. But yes, if OneWeb were to start making heavy use of New Glenn, that would result in still more congestion on the Eastern Range. Note that I've got New Glenn starting out at 4 launches/year in 2020, rising up to no more than 8/year by 2023. That might be too conservative.TheRadicalModeratehttps://www.blogger.com/profile/04671143818738683349noreply@blogger.comtag:blogger.com,1999:blog-5572744113321145124.post-39989012579629784682018-12-16T05:14:06.526-06:002018-12-16T05:14:06.526-06:00I also then wonder about the viability of one web ...I also then wonder about the viability of one web and Boeings sat constellations...wouldn't they be under threat as well? Lots of big dreams becoming reality now that viable business models existUnknownhttps://www.blogger.com/profile/02517501210699202442noreply@blogger.com