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The BFR and MCT should be considered as BFR (a 1st stage with 3.5km/s delta V with MCT sitting on top) and the MCT (an US with 7km/s delta v with a 100mt payload). This will get 100mt into LEO high orbit with dry tanks or into a lower orbit such that the MCT without payload (it has about 20mt of prop left at this low LEO orbit) can return and do a powered landing on Earth. This vehicle would be the minimum for a Mars system. It would be considered like the F9v1.0 with a more capable v1.1 being introduced 3 years later (raptor engine upgrade) such that the MCT can carry more propelant ~350mt more propelant and have a delta V of 8km/s. This vehicle would have nearly 120mt of residual prop at LEO. The main difference between these two versions is the number of tanker flights required to get the MCT off to Mars. The v1.0 vehicle would only deliver ~125mt of prop to LEO whereas the v1.1 would deliver 220mt of prop to LEO. The main cost of the MCT going to Mars is the number of tanker flights required. The same amount of prop would be need for either the v1.0 or v1.1 MCT vehicles (to add 350mt of prop to the MCT that is 15m in diameter is a stretch in height of only .5-1m). Meaning less than half as many flights are needed for the v1.1 to get to Mars vs the v1.0. The cost of flights is relativly the same between the v1.0 and v1.1 since the majority of the costs are the processing costs and operations with only a 20% portion or less going toward the manufacturing cost of the vehicle.

There would be only 2 basic version of the MCT a personnel and a cargo. An empty cargo launch is used to deliver prop as residuals in the MCT tanks instead of creating a specialized tanker that would only have a few mt more prop delivery capability over that of using an empty cargo flight (not economically cost effective to have a third version as well as its development cost).

You are correct that a BFR/MCTv1.0 would deliver only 30mt to GTO and return to Earth as a sat launcher but the BFR/MCT v1.1 could deliver that same 30mt all the way to GEO and return to Earth it could deliver almost 100mt into GTO. Its heavy weigh 80mt as a stage equivalent is what makes it a poor performer for such missions. But refuel it and it could deliver 100mt to anywhere in cis-Lunar space, including the Lunar surface, and return to Earth.

In order for the MCT to deliver itself and its 100mt of payload to the Mars surface it will need ~450mt of prop. This is 4 v1.0 tanker flights but only 2 v1.1 (actually 1.5, 3 tanker flights would send 2 MCTs to Mars). This makes the cost of going to Mars/flight for v1.0 = $400M and for v1.1 = $200M (at $80M per BFR/MCT launch).

The BFR/MCT design most difficult challenge is costs not technical and that challenge is directly related to how much mass can be put into LEO from Earth. A 30% increase in performance reduces the costs of going to Mars by a factor of 2.

So if 10 cargo are required for each 1 personnel then a personnel carry 100 passengers would make the cost per person using the v1.0 of $44M each and for v1.1 of $22M each.

The predominant number of Mars missions will be conducted by the v1.1 or even more capable vehicle with again lower per person cost by as much as a factor of 2 such that the MCT does not require being refueled in LEO (1 BFR/MCTv2.0 launch for 1 Mars flight).
With the limited throttle range of the Merlin 1D-Vac, if the upper stage burns to depletion to perform TLI, with sparrow as the only payload, what will the acceleration be like?

I believe the dispenser will also still be there, which is probably some not-insignificant mass.

Still, you have a point -- SpaceIL will definitely need to make sure Sparrow can handle high g loads!
With the limited throttle range of the Merlin 1D-Vac, if the upper stage burns to depletion to perform TLI, with sparrow as the only payload, what will the acceleration be like?
Spaceflight Entertainment and Hobbies / Re: Crawler redo at 1/72
« Last post by RichO on Today at 07:08 PM »
Spaceflight Entertainment and Hobbies / Re: Crawler redo at 1/72
« Last post by RichO on Today at 07:06 PM »
Another thread discussing fringe topics with a whole load of fuzzy data? I lurk here mostly, but I hope topics like this isn't a sign of where this site is headed.

Then go read the mainstream articles on it instead and please loose the attitude.  Here's a lovely update on LENR efforts from August by a Lawrence National Lab scientist:

Or if you simply want hard information on why the e-cat reactor doesn't work as advertised go here:

Honestly, I am still scratching my head over what changed between March when USPTO issued a "final rejection" letter to Rossi and August when they accepted the application and granted the patent, but I go do some primary research before shooting my mouth off.
Spaceflight Entertainment and Hobbies / Re: Crawler redo at 1/72
« Last post by RichO on Today at 07:05 PM »
Hey Everybody,

  I thought I should get this thread cought up with whats been going on with this build. I have about a hundred photos, so this may take a bit to load all of these.

I left off just at the end of the walkway chapter. So now a look at the final walkway build.
SpaceX General Section / Re: MCT Speculation and Discussion Thread 4
« Last post by Lobo on Today at 07:05 PM »

No. If you are truly scaling this to be able to deliver 100t of cargo, you really need to have it in the middle. Not up front with the hab volume. When you do atmospheric entry, the propellant tanks will be mostly empty, so then by placing the cargo up top you are now forcing yourself to have to have a substantial minimum cargo load or the thing won't fly right.

Think about it. 100t. And it could be there, or it could be empty. If you do a sideways re-entry, that DOES constrain you to a center placement of cargo. OR you need to split the cargo into two balanced areas, one below and one above propellant tanks.

It's 100mt of payload.   That may be 100mt of pure cargo down the road at some point, but for quite some time it will be mixed cargo and crew/hab. 

So you have your IBMCT.  It has it's fairly heavy MPS on the bottom.  Above that you have two stacked cylindrical tanks that go up to about the center of the overall vehicle (when measured from tip to tail)...up a little over half way up the cylindrical portion.  Above that you'll have a cargo deck for mixed flights that is maybe 3 meters tall.  As the cargo will have to be lowered to the surface, none of it can be -too- large in one piece, but it will be heavy overall.  Above that you will have a pressurized hab volume filling the rest of the cylinder, and then another tapered pressurized hab volume in the nose.  If an LAS is required, the nose will have LAS/landing engines it it as well, along with small pressurized tanks to fuel them.   Overall, it will have a fair amount of mass in it.
So again, you'll have a mass area in the tail, amidships, and in the nose. 

With 100mt of pure cargo, and no hab area at all, that may be a little more tricky if all that 100mt is between the nose and the tanks.  They'd probably stow the heaviest pieces just above the tanks, with lighter and lighter pieces above that to help with weight distribution.

But, it's obviously something that'd have to be looked at in more detail by actual SpaceX engineers during the actual design process to see how the real weight distribution will interact with the EDL profile.

This divided concept would have the problem of being nose-light.  The mass will be concentrated in the middle, and at the aft in the MPS.  But given it's tapered overall OML, maybe that still makes for a feasible distribution for EDL?  It's a little above my area.  :-)

With the SDMCT, obviously that's not a problem because it's always vertical.
Uh, what VCs ( or seed funds, or angels ) want and expect from you depends very much on the stage you are in. Seed, series-A and series-B all have very different expectations. But this discussion is probably best held in a 'general section' somewhere.
Moved for live coverage.

This may be the first live launch I'll miss since I started the site. Have a big dentist appointment they won't move. Technically I should be out and back on the net ahead of T-0, but it's going to be tight, so we'll need you all to chip in (hopefully with Steven will be around to provide his excellent coverage).

Hopefully my appointment will be on time, I'll get out in good time and rush back with a swollen mouth before they come out of the hold! :)

Do please take care not to get yourself killed while driving five times the speed limit in an anesthetic-induced stupor. That would probably cause issues for the site  ;)
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