Gwynne mentioned the diameter of the fairing being 8 meters for BFR allowing very large sats. Has the BFR stack shrunk in diameter since 2017?
SpaceX showed pictures of BFS's landed in exotic locations like asteroids or Jupiter's moons. Those would be very hard to get back. If they fueled in Mars orbit, they could send a probe with another propulsion module off to a much faster trip outbound, but we're still talking about a trip beyond its designed capabilities.
Quote from: Darkseraph on 04/26/2018 10:51 amGwynne mentioned the diameter of the fairing being 8 meters for BFR allowing very large sats. Has the BFR stack shrunk in diameter since 2017?More or less makes sense if it's interior vs exterior diameter.
Quote from: llanitedave on 04/18/2018 09:44 pmSpaceX showed pictures of BFS's landed in exotic locations like asteroids or Jupiter's moons. Those would be very hard to get back. If they fueled in Mars orbit, they could send a probe with another propulsion module off to a much faster trip outbound, but we're still talking about a trip beyond its designed capabilities.Hard to get back if you're doing a one shot. But that's the wrong way to think about this. Jupiter's moons are just another destination that needs infrastructure emplaced enroute. Stop thinking flags and footprints, and start thinking about transportation network extension, step by step. Railways managed to get all the way from Omaha to San Francisco, despite locomotives only being able to carry water for maybe 100 miles of travel and fuel for 2-300. At most. It was done incrementally. As the track was extended, gangs followed behind building wells, dams, water tanks, coaling depots, maintenance facilities, crew lodging, freight depots, and all the rest. All the materials they couldn't ISRU (everything except maybe timbers and rocks and dirt) were brought along, and as facilities were built, it got easier and easier to bring more materials. (fan to mod transition) Also, the concept of interstellar is not off topic., She mentioned it. But detailed discussion of how to do it in general? Off topic beacuse we have lots of other threads.
I guess they plan to be able to fill the whole thing with propellant and launch in less than 2 hours.
Questioned about whether governments will allow it, she said it wouldn’t have seemed likely the USAF would allow F9 boosters to fly back to their property and this is 10 km off shore.
I've read sound propagates better over water. Are there any calculations on the acoustic pollution produced by a BFR 5-10km offshore a major city?
Quote from: AbuSimbel on 04/28/2018 01:09 pmI've read sound propagates better over water. Are there any calculations on the acoustic pollution produced by a BFR 5-10km offshore a major city?Yes it does propagate well. I am very familiar with the Isle of Shoals ~6 miles off the NH coast and city of Portsmouth. I would be seriously surprised if any commercial passenger launch site outside a major city, assuming any are ever built, is less than 10 miles or 16Km offshore. These are very big rockets.
Quote from: Ludus on 04/28/2018 05:28 amI guess they plan to be able to fill the whole thing with propellant and launch in less than 2 hours. The main phase of filling the propellant in F9 and launching takes under half an hour, with most completed in 15 minutes.It starts only about an hour and twenty minutes before launch.
Quote from: philw1776 on 04/28/2018 01:14 pmQuote from: AbuSimbel on 04/28/2018 01:09 pmI've read sound propagates better over water. Are there any calculations on the acoustic pollution produced by a BFR 5-10km offshore a major city?Yes it does propagate well. I am very familiar with the Isle of Shoals ~6 miles off the NH coast and city of Portsmouth. I would be seriously surprised if any commercial passenger launch site outside a major city, assuming any are ever built, is less than 10 miles or 16Km offshore. These are very big rockets.I wonder if there are sound suppression techniques that might apply to this situation. I understand that the water systems used at some pads are for this. If it’s a pad at sea there might be new approaches to suppressing sound in the direction of the city.
Sound travels well over water because it's a perfectly flat surface. Maybe some installation around the pad to deflect the sound waves slightly upwards?
The President and Chief Operating Officer of SpaceX said 5-10km offshore. She wouldn't have said that unless SpaceX had analyzed all aspects of the offshore pad at those distances, including sound.In the absence of any information, speculation is fine. It's part of what makes this a great forum.But when we have it straight from the horse's mouth, speculation otherwise seems pointless.
Quote from: niwax on 04/29/2018 12:57 pmSound travels well over water because it's a perfectly flat surface. Maybe some installation around the pad to deflect the sound waves slightly upwards?The rocket travels upwards too, quite a long way up. I can't think how you could shield from that.
A more mundane possibility: Asking about stuff that would happen 20/35/50 years from now is a bit ridiculous from Gwynnes perspective. She is responsible for the economic success of SpaceX. She has necessarily a horizon of maybe 5 years or some more in some long term development projects. From her perspective, talking about stuff that is 4 to 10 times her current time horizon, there is no way she can give a sensible answer. So she gives intentionally a ridiculous one.