Xd the great Posted September 27, 2018 Share Posted September 27, 2018 12 hours ago, magnemoe said: Yes, note that you can refuel in orbit so no need to launch fuel. its only an issue if you launch stuff who can not be broken down to pieces less than 150 ton. Nuclear reactors? note that you can add shielding in orbit if reactor is not started. What if the bfr blows and spread nuclear material everywhere. Quote Link to comment Share on other sites More sharing options...
NSEP Posted September 27, 2018 Share Posted September 27, 2018 3 minutes ago, Xd the great said: What if the bfr blows and spread nuclear material everywhere. It would be bad, but i think the nuclear reactors would be inside some special packaging, so that if the rocket explodes the nuclear material doesn't explode with it and go everywhere. Not exactly sure how that would work, or if there is a better alternative, but hey, we have 100 tons of free space to mess with sooooo... Quote Link to comment Share on other sites More sharing options...
magnemoe Posted September 27, 2018 Share Posted September 27, 2018 2 hours ago, NSEP said: It would be bad, but i think the nuclear reactors would be inside some special packaging, so that if the rocket explodes the nuclear material doesn't explode with it and go everywhere. Not exactly sure how that would work, or if there is a better alternative, but hey, we have 100 tons of free space to mess with sooooo... Add that the reactor would not be started so it the radioactive material would be enriched uranium who is not very radioactive. However my point was that its an limited number 150 ton items who can not be divided up and is less than 1000 m^3. Now one option is to use all the fuel in the upper stage, you would need to refuel before landing but this would change that fuel from being "dry mass" to extra fuel. Quote Link to comment Share on other sites More sharing options...
nasa legolas Posted September 27, 2018 Share Posted September 27, 2018 its kind of possible. the stratier 24 nuclear tests tried this out and it spread to australia (btw. it was a 5 megaton reactor core). Quote Link to comment Share on other sites More sharing options...
cubinator Posted September 27, 2018 Share Posted September 27, 2018 5 hours ago, Xd the great said: What if the bfr blows and spread nuclear material everywhere. Do it after BFR has flown 100 times in a row with no catastrophic failures. At that point it's probably pretty safe. Quote Link to comment Share on other sites More sharing options...
sh1pman Posted September 27, 2018 Share Posted September 27, 2018 (edited) BTW, are there any numbers on how much mass can BFR send to GTO and GEO without refueling? Can it even get to GEO with any significant payload? Edited September 27, 2018 by sh1pman Quote Link to comment Share on other sites More sharing options...
Ultimate Steve Posted September 27, 2018 Share Posted September 27, 2018 26 minutes ago, sh1pman said: BTW, are there any numbers on how much mass can BFR send to GTO and GEO without refueling? Can it even get to GEO with any significant payload? The DearMoon plans show no refueling launches (although I still think they are better off with at least 1) so currently, BFR is theoretically capable of going past the moon with 0 payload. I think this will change. The cargo version of BFR will be significantly more capable due to the lack of a pressurized crew compartment with all the systems necessary, so if the lack of refueling on the moon mission is true, I'd imagine it can take a few tons to GTO, but probably nothing to GEO. Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted September 27, 2018 Share Posted September 27, 2018 Given that it’ll only be carrying 6-8 people for around a week, not a hundred for months, I’m wondering if this ship will be some sort of hybrid, with crew accommodations traded for extra fuel. Maybe a small crew/big cargo variant that’s modular enough to install extra fuel tanks in the cargo bay? Quote Link to comment Share on other sites More sharing options...
NSEP Posted September 27, 2018 Share Posted September 27, 2018 1 hour ago, sh1pman said: BTW, are there any numbers on how much mass can BFR send to GTO and GEO without refueling? Can it even get to GEO with any significant payload? Nothing official yet, but considering most GTO payload masses are half that of LEO masses, i estimate it can send around 50 tons to GTO, without refueling. 3 minutes ago, CatastrophicFailure said: Given that it’ll only be carrying 6-8 people for around a week, not a hundred for months, I’m wondering if this ship will be some sort of hybrid, with crew accommodations traded for extra fuel. Maybe a small crew/big cargo variant that’s modular enough to install extra fuel tanks in the cargo bay? The cargo bay volume increased from 825^3 meters, to 1000^3 meters. Its definitely possible that there is maybe extra fuel in there, but i don't think thats the case. Developing a plumbing system for some mind of modular fuel tank and testing it might not be worth the risk, for a 'simple' circumlunar flight like this. Once BFR becomes more widespread and colonization begins, a modular cargo/fuel system and multiple BFR variants will definitely make alot of sense. They can also use the extra space to make the tourist feel a little bit more at home inside the spacecraft, during the trip. Extra empty space in a Zero-g environment is something ISS Astronauts and Cosmonauts are probably craving for. Quote Link to comment Share on other sites More sharing options...
sh1pman Posted September 27, 2018 Share Posted September 27, 2018 (edited) 2 hours ago, NSEP said: Nothing official yet, but considering most GTO payload masses are half that of LEO masses, i estimate it can send around 50 tons to GTO, without refueling. For F9 it’s 23t to LEO and 8t to GTO. So more like a quarter to one third of LEO mass, or 25-35t for BFR. And considering that we now don’t have vacuum Raptors, I’d say it’s closer to 25t. Edited September 27, 2018 by sh1pman Quote Link to comment Share on other sites More sharing options...
mikegarrison Posted September 27, 2018 Share Posted September 27, 2018 Looks like my question a few weeks ago may be relevant. The SEC today sued Musk, seeking to forbid him from running any public companies, on the basis that he has lied to investors. That would include SpaceX. https://www.seattletimes.com/business/sec-sues-teslas-elon-musk-alleging-he-lied-to-investors/ Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted September 27, 2018 Share Posted September 27, 2018 1 minute ago, mikegarrison said: Looks like my question a few weeks ago may be relevant. The SEC today sued Musk, seeking to forbid him from running any public companies, on the basis that he has lied to investors. That would include SpaceX. https://www.seattletimes.com/business/sec-sues-teslas-elon-musk-alleging-he-lied-to-investors/ SpaceX isn’t a publically-traded company, tho, it’s already (still) Private. Quote Link to comment Share on other sites More sharing options...
mikegarrison Posted September 27, 2018 Share Posted September 27, 2018 Just now, CatastrophicFailure said: SpaceX isn’t a publically-traded company, tho, it’s already (still) Private. I wondered about that. The article specifically says it would include SpaceX, but I think if SpaceX isn't publicly traded then it wouldn't. Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted September 27, 2018 Share Posted September 27, 2018 4 minutes ago, mikegarrison said: I wondered about that. The article specifically says it would include SpaceX, but I think if SpaceX isn't publicly traded then it wouldn't. I will continue to hold journalistic integrity as suspect when it comes to Mr. Musk. Quote Link to comment Share on other sites More sharing options...
Spaceception Posted September 27, 2018 Share Posted September 27, 2018 (edited) I suppose SpaceX would be in pretty good hands with Gwynne Shotwell. But what about Musk's other companies? Boring, Telsa, etc? I wonder if there's people who could faithfully take the reigns. Either for now, or permanently.. albeit with less controversy. Edited September 27, 2018 by Spaceception Quote Link to comment Share on other sites More sharing options...
mikegarrison Posted September 27, 2018 Share Posted September 27, 2018 9 minutes ago, Spaceception said: I suppose SpaceX would be in pretty good hands with Gwynne Shotwell. But what about Musk's other companies? Boring, Telsa, etc? I wonder if there's people who could faithfully take the reigns. Either for now, or permanently.. albeit with less controversy. Tesla is the source of the problem. It all goes back to his tweet that he had investors ready to take Tesla private at $420/share. A lot of people lost a lot of money reacting to that tweet. They are definitely trying to get him booted from Tesla. Quote Link to comment Share on other sites More sharing options...
Spaceception Posted September 27, 2018 Share Posted September 27, 2018 2 minutes ago, mikegarrison said: Tesla is the source of the problem. It all goes back to his tweet that he had investors ready to take Tesla private at $420/share. A lot of people lost a lot of money reacting to that tweet. They are definitely trying to get him booted from Tesla. Yeah... I wonder what the outcome will be. Unfortunately, people will start bashing Tesla/SpaceX/etc more now Even though their internal work is still really good, and impressive. Quote Link to comment Share on other sites More sharing options...
CatastrophicFailure Posted September 27, 2018 Share Posted September 27, 2018 11 minutes ago, Spaceception said: Yeah... I wonder what the outcome will be. Unfortunately, people will start bashing Tesla/SpaceX/etc more now Even though their internal work is still really good, and impressive. Haters always gonna hate, the lines have already been drawn so I doubt this will change anything. It’s far from a foregone conclusion, after all, they have to demonstrate that Musk did what he did knowingly and with intent, and as was mentioned upthread, that will prove difficult. I imagine that suit will just quietly go away after a few weeks. Quote Link to comment Share on other sites More sharing options...
mikegarrison Posted September 27, 2018 Share Posted September 27, 2018 28 minutes ago, CatastrophicFailure said: I imagine that suit will just quietly go away after a few weeks. I am certain that will not be the case. The US government does not bring such suits on a whim. Quote Link to comment Share on other sites More sharing options...
sh1pman Posted September 27, 2018 Share Posted September 27, 2018 Still, it’s not affecting SpaceX in any way since it’s not a publicly traded company. Can we please get back to SpaceX stuff? Quote Link to comment Share on other sites More sharing options...
magnemoe Posted September 27, 2018 Share Posted September 27, 2018 5 hours ago, NSEP said: Nothing official yet, but considering most GTO payload masses are half that of LEO masses, i estimate it can send around 50 tons to GTO, without refueling. The cargo bay volume increased from 825^3 meters, to 1000^3 meters. Its definitely possible that there is maybe extra fuel in there, but i don't think thats the case. Developing a plumbing system for some mind of modular fuel tank and testing it might not be worth the risk, for a 'simple' circumlunar flight like this. Once BFR becomes more widespread and colonization begins, a modular cargo/fuel system and multiple BFR variants will definitely make alot of sense. They can also use the extra space to make the tourist feel a little bit more at home inside the spacecraft, during the trip. Extra empty space in a Zero-g environment is something ISS Astronauts and Cosmonauts are probably craving for. Payload bay for the crewed version is just one deck, 2*4.5^2*pi=40. so 80-100 m"3. subtract wall thickness, airlock and other stuff. Not much room for fuel, probably not practical. The tanker version will however hold extra fuel in the cargo hold. You could also replace the door with an bolted hatch to save weight. And yes an larger cargo hold on some of the manned BFR would make sense for multiple missions. 2 hours ago, sh1pman said: For F9 it’s 23t to LEO and 8t to GTO. So more like a quarter to one third of LEO mass, or 25-35t for BFR. And considering that we now don’t have vacuum Raptors, I’d say it’s closer to 25t. Falcon 9 is weak to GTO compared to rockets like Ariadne who has an small 3rd hydrolox stage. BFR has higher isp than falcon 9 but the second stage dry mass is also far higher. Quote Link to comment Share on other sites More sharing options...
tater Posted September 28, 2018 Share Posted September 28, 2018 This is kinda interesting, and I put it here because Iridium is a good, and vocally supportive SpaceX customer: Iridium working with Amazon... Quote Link to comment Share on other sites More sharing options...
Nightside Posted September 28, 2018 Share Posted September 28, 2018 10 hours ago, tater said: This is kinda interesting, and I put it here because Iridium is a good, and vocally supportive SpaceX customer: <...> Iridium working with Amazon... The plan sounds a lot like Starlink. Quote Link to comment Share on other sites More sharing options...
Mad Rocket Scientist Posted September 28, 2018 Share Posted September 28, 2018 https://forum.nasaspaceflight.com/index.php?action=dlattach;topic=44715.0;attach=1511827;image Cape Canaveral F9 sonic boom map overlaid on Vandenberg, courtesy of NSF. I can't believe I'm probably going to have to miss seeing this in person. Quote Link to comment Share on other sites More sharing options...
tater Posted September 28, 2018 Share Posted September 28, 2018 Quote Link to comment Share on other sites More sharing options...
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