Quote from: philw1776 on 01/26/2016 06:15 pmMaybe a poll forecasting Musk's coming out of the closet date?How about a poll with the top ten BFS/BFR designs and mission architectures?
Maybe a poll forecasting Musk's coming out of the closet date?
Musk already dropped a date for when he wants to reveal the architecture: September 26-30.
Quote from: The Amazing Catstronaut on 01/26/2016 11:54 pmMusk already dropped a date for when he wants to reveal the architecture: September 26-30. Hopefully all the speculation on BFR/MCT system will end then.
Quote from: Paul451 on 01/26/2016 11:45 pmQuote from: philw1776 on 01/26/2016 06:15 pmMaybe a poll forecasting Musk's coming out of the closet date?How about a poll with the top ten BFS/BFR designs and mission architectures?Who compiles the 1000 page pdf document detailing these?
Yes, BSenna. You and I are thinking alike.I do not have a specific concept of the MCT design; I just react to new info as I discover it. I have some experience as a engineering project manager but my principle role now is "Idea Man." But as a team player I am ready to change my concepts when a better idea is presented. So if you and I were to work together, you should take the lead on what the MCT design is likely to be.My arena would be an idea about a structure that the MCT architecture will require: an in-space propellant depot. If interested, it has 3 threads on this forum so far, starting with this:http://forum.nasaspaceflight.com/index.php?topic=38146.0
You mean just like all speculation on the Falcon 9, Dragon 2, and Falcon Heavy have stopped?
Quote from: nadreck on 01/27/2016 01:29 pmYou mean just like all speculation on the Falcon 9, Dragon 2, and Falcon Heavy have stopped?People will stop suggesting completely alternative architectures and instead speculate about architecture upgrades. That will cut some of the 'Dastardly and Muttley in Their Flying Machines/Catch that pigeon' proposals.
Excuse my cynicism but even before the USAF award to develop a raptor or raptor variant for FH and F9 upper stage use it had been discussed for a long time here along with potential F9 or FH new reusable US. So I fully expect that whatever Musk announces in September some variants in both overall architecture (including depot/refuelling, upper stage types, dependencies on site preparation at Mars, Mars ISRU and depots, SEP on BFS, BFS return to Earth surface, LEO, LM-1/2, etc) and specific details (BFS engine arrangement, TPS, BFB recovery, BFS ECLSS, BFS cargo arrangemnt etc) will still get debated well outside guidelines of where SpaceX says it will be going.
I took a look at the propellant depot project and it looks great, very refined. But unfortunately is too much for my technical limitations, so, I didn't undestood it completely, but I trust on you guys!I could start a 3d model, but my habilities are really limited. I have some doubts:I assume that the MCTs which will trasport the fuel to LEO are of a similar size and mass of the crewed MCT, so, they're not full of fuel when reach the depot, right? If It's the case, would there be any advantage on leaving only a smaler fuel tank on each of these missions and returning to land to fly again on the same role, thus reducing the total fleet of MCT-SIIs) and also reducing the total mass of the complete transit to mars vehicle? Or The rockets on these MCTs are also necessary to throw the complete vehicle to Mars?Once on Mars, just the crewd MCT would land, refuel and return to meet the rest of the vehicle?Then, all 7 MCTs would land on Earth for refurbishing?
Here's the way I see the Depot working:The first half dozen or so trips to Mars will carry cargo to set up habitats, ISRU machinery, and remote-contolled equipment. These preliminary forays will prepare a base for humans who will arrive later. A cargo MCT launching from Earth will be heavily loaded; it will use up essentially all its fuel just to get to the depot in orbit. It will require a refill before proceeding any further. We will have a tanker variant of MCT, which has the same basic outer shell as a cargo or passenger version, but will be hollowed out as a big fuel carrier. The volume that would otherwise be cargo volume will be devoted to big fuel tanks. This could be just an expansion of the the main tanks that extend into the the cargo space. Its principle function will be to haul fuel from Earth to the depot, probably about 250 tonnes of CH4 and LOX in each trip. . Three or four loads of fuel must be transferred to the cargo-MCT before it can proceed to Mars.We could just make a series of trips to the waiting cargo ship and sequentially fill it up. But having a depot allows us to fill up multiple cargo ships and launch as a fleet to Mars. This is the stated intent of SpaceX.So tanker #1 arrives at the depot and docks at a berth. Tanker #2 arrives at the depot and transfers its fuel load to tanker #1, reserving just enough fuel to return to Earth via propulsive landing. These tankers are highly reusable and require little maintenance between flights, like an airplane. Tanker #2 refills at the launch site and launches again to the depot. It again transfers its fuel load to tanker #1 and returns to the launch site. Now tanker # 1 has enough fuel in its tanks to service one cargo MCT. And because we have six berths at the depot, we can perform this procedure three times simultaneously using six tanker MCTs.Now three cargo ships arrive at the depot and dock beside three refilled tankers. The tankers transfer their fuel loads to the cargo ships and return to Earth.We have three cargo carriers ready to trek to Mars with full bellies.
Quote from: Ionmars on 01/27/2016 11:10 pmBlah,, blah... blah......Undesrtood!
Blah,, blah... blah......
We will have a tanker variant of MCT, which has the same basic outer shell as a cargo or passenger version, but will be hollowed out as a big fuel carrier. The volume that would otherwise be cargo volume will be devoted to big fuel tanks. This could be just an expansion of the the main tanks that extend into the the cargo space. Its principle function will be to haul fuel from Earth to the depot, probably about 250 tonnes of CH4 and LOX in each trip. . Three or four loads of fuel must be transferred to the cargo-MCT before it can proceed to Mars.
Quote from: Ionmars on 01/27/2016 11:10 pm We will have a tanker variant of MCT, which has the same basic outer shell as a cargo or passenger version, but will be hollowed out as a big fuel carrier. The volume that would otherwise be cargo volume will be devoted to big fuel tanks. This could be just an expansion of the the main tanks that extend into the the cargo space. Its principle function will be to haul fuel from Earth to the depot, probably about 250 tonnes of CH4 and LOX in each trip. . Three or four loads of fuel must be transferred to the cargo-MCT before it can proceed to Mars.Cargo density is far lower than fuel density, so either the tanker is smaller or it has a lot of unused cargo volume.I don't understand why you would need a depot though. Why not just have the tanker dock with the MCT and transfer propellent?
Quote from: BSenna on 01/28/2016 12:39 amQuote from: Ionmars on 01/27/2016 11:10 pmBlah,, blah... blah......Undesrtood!If you were to do a 3D model of the Depot it would just be a 2D (x,y) skeletal frame that is repeated into the third (z) dimension. Below is a sketch of the forward frame for one berth. The small circle is a "pad" for connecting to the nose of the MCT and the large circle is an imaginary volume representing one berth where one MCT is docked. The frames are connected by beams of a certain length in the z dimension. Then this 3D image is duplicated side-by-side to the right to make 5 additional berths until they join on the left side of the first berth. Voila!