Ultimate Steve Posted October 14, 2017 Share Posted October 14, 2017 2800 comments... Yeah, I won't be noticed. I think he answered, like, 15 last year. Quote Link to comment Share on other sites More sharing options...
sh1pman Posted October 14, 2017 Share Posted October 14, 2017 How do we know which ones he answers? There are thousands of questions, is there a filter by user or something? Quote Link to comment Share on other sites More sharing options...
Ultimate Steve Posted October 14, 2017 Share Posted October 14, 2017 1 minute ago, sh1pman said: How do we know which ones he answers? There are thousands of questions, is there a filter by user or something? You can click on his user profile. So far he hasn't answered any yet. Also he's up to 6 gildings. Quote Link to comment Share on other sites More sharing options...
StupidAndy Posted October 14, 2017 Share Posted October 14, 2017 3 minutes ago, Ultimate Steve said: You can click on his user profile. So far he hasn't answered any yet. Also he's up to 6 gildings. he has now answered...one! Quote Link to comment Share on other sites More sharing options...
TheEpicSquared Posted October 14, 2017 Share Posted October 14, 2017 3 minutes ago, Ultimate Steve said: You can click on his user profile. So far he hasn't answered any yet. Also he's up to 6 gildings. He has responded! His first response is "We chickened out". Quote Link to comment Share on other sites More sharing options...
Ultimate Steve Posted October 14, 2017 Share Posted October 14, 2017 1 minute ago, StupidAndy said: he has now answered...one! Raptor thrust was reduced because Elon "Chickened out..." Quote Link to comment Share on other sites More sharing options...
RedKraken Posted October 14, 2017 Share Posted October 14, 2017 Raptor thrust reduction from 3MN to 1.7MN : "We chickened out." Quote Link to comment Share on other sites More sharing options...
Ultimate Steve Posted October 14, 2017 Share Posted October 14, 2017 He says the BFS now has 3 sea level engines. I think. Quote Link to comment Share on other sites More sharing options...
Nightfury Posted October 14, 2017 Share Posted October 14, 2017 Where I can watch/read the AMA ? Quote Link to comment Share on other sites More sharing options...
sh1pman Posted October 14, 2017 Share Posted October 14, 2017 >The engine thrust dropped roughly in proportion to the vehicle mass reduction from the first IAC talk. In order to be able to land the BF Ship with an engine failure at the worst possible moment, you have to have multiple engines. The difficulty of deep throttling an engine increases in a non-linear way, so 2:1 is fairly easy, but a deep 5:1 is very hard. Granularity is also a big factor. If you just have two engines that do everything, the engine complexity is much higher and, if one fails, you've lost half your power. Btw, we modified the BFS design since IAC to add a third medium area ratio Raptor engine partly for that reason (lose only 1/3 thrust in engine out) and allow landings with higher payload mass for the Earth to Earth transport function. Interesting. So looks like he went all in with this surface-to-surface idea. Quote Link to comment Share on other sites More sharing options...
Ultimate Steve Posted October 14, 2017 Share Posted October 14, 2017 Just now, Nightfury said: Where I can watch/read the AMA ? Quote Link to comment Share on other sites More sharing options...
TheEpicSquared Posted October 14, 2017 Share Posted October 14, 2017 Just now, Nightfury said: Where I can watch/read the AMA ? Reddit, at r/space Quote Link to comment Share on other sites More sharing options...
Nightfury Posted October 14, 2017 Share Posted October 14, 2017 Ah, thanks Quote Link to comment Share on other sites More sharing options...
RedKraken Posted October 14, 2017 Share Posted October 14, 2017 (edited) So a third SL engine on the BFS.... Interesting implication for stage sea-level testing....before the BFS could take off @ ~ 280t wet....... now 420t (5370m/s of deltaV) Can't wait to see the BFS practicing its landings! Edited October 14, 2017 by RedKraken Quote Link to comment Share on other sites More sharing options...
RedKraken Posted October 14, 2017 Share Posted October 14, 2017 Satellites for mars : they are going to need some serious telemetry for the mars edl attempts....martian gps? ..........and an array of surface radar/science units along the landing path? Quote Link to comment Share on other sites More sharing options...
Ultimate Steve Posted October 14, 2017 Share Posted October 14, 2017 When asked what dev progress they will make in 5 years, he responded with "a lot" and 3 yes's, referring to the construction of a grasshopper BFR, that propellant plants will be tested, and that facilities will be built. Sort of vague. He also called someone a nerd before responding with an incredibly nerdy response, made a bob the builder reference, and when told the AMA was going oddly he said "just wait..." Quote Link to comment Share on other sites More sharing options...
RedKraken Posted October 14, 2017 Share Posted October 14, 2017 Instant bragging rights for the guy that elon called a nerd. (/r/general-information) Quote Link to comment Share on other sites More sharing options...
Ultimate Steve Posted October 14, 2017 Share Posted October 14, 2017 In total he's up to 13 gildings so far... I bet it will get above 20 if the AMA goes on much longer. Quote Link to comment Share on other sites More sharing options...
sh1pman Posted October 14, 2017 Share Posted October 14, 2017 (edited) I've been launching 3.75m BFRs all day in KSP today. Man, they're great in career mode! Way easier to fly than SSTOs, easy to recover first stage with StageRecovery mod, lots and lots of delta-v with refueling (did a direct Moho transfer with 20t payload). I even managed to land a BF Ship on top of Mission Control. Don't know how BFR will work out in real life, but in KSP it rocks. UPD: Here's a few nice screenshots: Spoiler Edited October 14, 2017 by sh1pman Quote Link to comment Share on other sites More sharing options...
tater Posted October 14, 2017 Share Posted October 14, 2017 Quote Will be starting with a full-scale Ship doing short hops of a few hundred kilometers altitude and lateral distance. Those are fairly easy on the vehicle, as no heat shield is needed, we can have a large amount of reserve propellant and don't need the high area ratio, deep space Raptor engines. Next step will be doing orbital velocity Ship flights, which will need all of the above. Worth noting that BFS is capable of reaching orbit by itself with low payload, but having the BF Booster increases payload by more than an order of magnitude. Earth is the wrong planet for single stage to orbit. No problemo on Mars. Quote Link to comment Share on other sites More sharing options...
RedKraken Posted October 14, 2017 Share Posted October 14, 2017 (edited) "Worth noting that BFS is capable of reaching orbit by itself with low payload, but having the BF Booster increases payload by more than an order of magnitude. Earth is the wrong planet for single stage to orbit. No problemo on Mars." On earth, the BFS will need 9 sealevel engines just to lift off @ 1185t. Probably 10 for twr. Unless the dry mass has changed, i would think zero payload and heavily modified? " The advantage of getting somewhere in 30 mins by rocket instead of 15 hours by plane will be negatively affected if "but also, you might die" is on the ticket." Greatest joyride on the planet. Edited October 14, 2017 by RedKraken Quote Link to comment Share on other sites More sharing options...
Ultimate Steve Posted October 14, 2017 Share Posted October 14, 2017 He has said that at first the tanker will be an empty cargo ship, but later it will be a dedicated tanker which will look weird. Quote Link to comment Share on other sites More sharing options...
RedKraken Posted October 14, 2017 Share Posted October 14, 2017 "The control thrusters will be closer in design to the Raptor main chamber than SuperDraco and will be pressure-fed to enable lowest possible impulse bit (no turbopump spin delay)" Cool. Quote Link to comment Share on other sites More sharing options...
Ultimate Steve Posted October 14, 2017 Share Posted October 14, 2017 He made a Harry Potter Reference. Quote Link to comment Share on other sites More sharing options...
RedKraken Posted October 14, 2017 Share Posted October 14, 2017 (edited) will all Raptor engines have heat exchangers? "yes and probably" "Some parts of Raptor will be printed, but most of it will be machined forgings. We developed a new metal alloy for the oxygen pump that has both high strength at temperature and won't burn. Pretty much anything will burn in high pressure, hot, almost pure oxygen." We are getting some good info here. Edited October 14, 2017 by RedKraken Quote Link to comment Share on other sites More sharing options...
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