tater Posted October 7, 2019 Share Posted October 7, 2019 Quote Link to comment Share on other sites More sharing options...
RCgothic Posted October 7, 2019 Share Posted October 7, 2019 Is 100kN feasible for hot gas RCS thrusters? Space Shuttle's primary RCS was under 4kN each and the primary OMS engines less than 30kN each. Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted October 7, 2019 Share Posted October 7, 2019 31 minutes ago, RCgothic said: Is 100kN feasible for hot gas RCS thrusters? Space Shuttle's primary RCS was under 4kN each and the primary OMS engines less than 30kN each. I don't see why not. Methane-oxygen has a great combustion cycle. Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted October 7, 2019 Share Posted October 7, 2019 I sense a disturbance... Hoooo, ho ho ho ho ho, haaah hah hah hah hah hah... Quote Link to comment Share on other sites More sharing options...
Jacke Posted October 7, 2019 Share Posted October 7, 2019 53 minutes ago, RCgothic said: Is 100kN feasible for hot gas RCS thrusters? Space Shuttle's primary RCS was under 4kN each and the primary OMS engines less than 30kN each. The primary OMS engines are virtually the same engine on the Apollo Service Module. 100kN is just over the thrust of the engine on the Viking sounding rocket. I'd say 100kN is way beyond an RCS thruster. Quote Link to comment Share on other sites More sharing options...
IncongruousGoat Posted October 8, 2019 Share Posted October 8, 2019 6 hours ago, Jacke said: The primary OMS engines are virtually the same engine on the Apollo Service Module. Not really. They're both variants of the AJ-10, but the Apollo SM engine had something like 90 kN of thrust, while the Shuttle's OMS engines had something more like 25 kN each. The designs were conceptually very similar, but the sheer difference in thrust means that they (very probably) had no components in common. Quote Link to comment Share on other sites More sharing options...
tater Posted October 8, 2019 Share Posted October 8, 2019 Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted October 8, 2019 Share Posted October 8, 2019 (edited) Dagnabbut, ninja’d and played by the stupid cache bug. Edited October 8, 2019 by CatastrophicFailure Quote Link to comment Share on other sites More sharing options...
tater Posted October 8, 2019 Share Posted October 8, 2019 Quote Link to comment Share on other sites More sharing options...
Jacke Posted October 8, 2019 Share Posted October 8, 2019 9 hours ago, IncongruousGoat said: Not really. They're both variants of the AJ-10, but the Apollo SM engine had something like 90 kN of thrust, while the Shuttle's OMS engines had something more like 25 kN each. The designs were conceptually very similar, but the sheer difference in thrust means that they (very probably) had no components in common. Well, that's interesting. I think the Apollo SPS was different enough from the other AJ-10 variants to really be its own separate design. Interesting document here from Clay Boyce, the engineer at Aerojet who was the manager of Apollo SPS development. Reading it sounds like despite the previous AJ-10's, each feature of the Apollo SPS was redesigned, partly due to the scale and due to the change to a pressure-fed throat-gimbled design. https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20100027319.pdf Quote Link to comment Share on other sites More sharing options...
tater Posted October 8, 2019 Share Posted October 8, 2019 Quote Link to comment Share on other sites More sharing options...
sevenperforce Posted October 8, 2019 Share Posted October 8, 2019 Word on the street over at SNF is that the strip weld reinforcement band on Mk1 is where the lower bulkhead and engine mount transfers force to the outer mold line. Quote Link to comment Share on other sites More sharing options...
tater Posted October 8, 2019 Share Posted October 8, 2019 I thought I would post the Elon Musk timeline for BFR dated from the first presentation about it 3 years ago, in September 2016. This will allow people to comment on "Elon time" in a realistic way... Red Dragon clearly bit it, costing everyone on Earth exactly nothing. Crew Dragon dev is clearly behind by about a year (ditto+ CST-100). BFR... 2019 has: Propulsion dev ending towards the beginning of the year. They were firing Raptor full duration by then, but dev continued for maybe 6 months after that, so a few months off schedule from this very "aspirational" 2016 chart. They have structure dev ending at the same time, early 2019. Interestingly, they abandoned all their work up to that time, and started over a couple months before the end of 2018, and they are clearly quite far along in this dev as of 1 year after that change, with them actually constructing multiple vehicles to test (1 close to done, one right behind that, and 2 in various stages of pre-assembly). Call it 1 year behind. Ship testing? Well, sort of begun with Hopper, and they are absolutely on a path to possibly meet that end of 2020 deadline (early 2020 for the 20 km flight). Orbital testing will require the booster, so the start of booster testing is likely more like mid to late 2020 than their late Spring on the chart. Still not impossible. So is it behind? Yeah. Is it really far behind this schedule? Not really. Maybe a year behind, maybe 6 months. Much less than I would have expected, honestly. Quote Link to comment Share on other sites More sharing options...
tater Posted October 8, 2019 Share Posted October 8, 2019 Regarding Crew Dragon, Bridenstine really needs to get someone in place where Gerst used to be. He has stated definitively that Gerst's replacement is the person who makes the call on putting crew on Dragon and Starliner. It;s already October, and SpaceX is planning a ground test of the Dragon to mimic the test that resulted in the RUD, then they use the same vehicle for the in flight abort test, and the crew vehicle is also going to be good to go all within 10 weeks. Any Gerst replacement could pull the trigger on crew maybe quickly if they are already in place at NASA doing the same thing, but I would have thought we'd see names floating around if that was the case. I can't imagine someone being named, then literally the first thing they do on the job is make that sort of decision in a short time frame. They need to get their feet under them, etc. In short, if the replacement isn't named pretty soon, any delays are the result of dumping Gerst. Quote Link to comment Share on other sites More sharing options...
mikegarrison Posted October 8, 2019 Share Posted October 8, 2019 Quote Link to comment Share on other sites More sharing options...
Thor Wotansen Posted October 8, 2019 Share Posted October 8, 2019 Interplanetary rock festival anyone? Everyone is expected to bring their own rocks. Quote Link to comment Share on other sites More sharing options...
tater Posted October 8, 2019 Share Posted October 8, 2019 36 minutes ago, mikegarrison said: I'm so glad you sent this AFTER I was done drinking coffee for the day. My keyboard thanks you, as well. Quote Link to comment Share on other sites More sharing options...
Nothalogh Posted October 8, 2019 Share Posted October 8, 2019 45 minutes ago, mikegarrison said: So it has always been, so it will always be. Quote Link to comment Share on other sites More sharing options...
ThatGuyWithALongUsername Posted October 8, 2019 Share Posted October 8, 2019 (edited) 9 minutes ago, Nothalogh said: So it has always been, so it will always be. War. War never changes. Edited October 8, 2019 by ThatGuyWithALongUsername Quote Link to comment Share on other sites More sharing options...
Nothalogh Posted October 8, 2019 Share Posted October 8, 2019 5 minutes ago, ThatGuyWithALongUsername said: War. War never changes. I was thinking more along the lines of Cormac McCarthy, "before man, war waited" Quote Link to comment Share on other sites More sharing options...
ThatGuyWithALongUsername Posted October 8, 2019 Share Posted October 8, 2019 9 minutes ago, Nothalogh said: I was thinking more along the lines of Cormac McCarthy, "before man, war waited" That works too Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted October 8, 2019 Share Posted October 8, 2019 Oh come on guys, get real. A united Mars would never destroy the earth. The Martians would be too busy destroying each other over which end of a Martian egg to open... Quote Link to comment Share on other sites More sharing options...
tater Posted October 8, 2019 Share Posted October 8, 2019 39 minutes ago, CatastrophicFailure said: The Martians would be too busy destroying each other over which end of a Martian egg to open... They'll be destroying each other to eat. Because they are starving to death. Quote Link to comment Share on other sites More sharing options...
Raven Industries Posted October 8, 2019 Share Posted October 8, 2019 The year is 2037. Due to insufficient allocation of resources towards psychological screening for Elon Musk's Mars Colony initiative, the 2 beachhead colonies have repurposed their nuclear bombs, meant for terraforming, into makeshift ICBMs to wage war upon each other over the proper side of bread on which to place the Spreadable fat-BAsed Nutritional Component (S-BANC, also known as margarine). Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted October 8, 2019 Share Posted October 8, 2019 The year is 2137. Due to insufficient allocation of resources towards... anything at all prior to the incident of 2037, one thing led to another and today the surviving members of the Global Congress voted unanimously to accept the surrender terms of the Martian Cockroach Ascendency. Quote Link to comment Share on other sites More sharing options...
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