Other than the Raptor engine, SpaceX has made the effort to build an actual size, "huuuuge", carbon-fiber test fuel tank for the spaceship, although doing this is no longer difficult -- 787, A350 seem to have nailed down the technology for large load bearing carbon-fiber structures...
http://blog.nss.org/wordpress/wp-conten ... x-tank.jpg
But just look at his video, I encourage watching all 90 min... https://www.youtube.com/watch?v=W9olSzNOh8s
...Seems he is simply hand-waving, passing the buck, downplaying major technology difficulties, and saying this is like the US 19th century transcontinental railroad -- build it and others will figure out how to use it. No! This is so different, Mars and planets are not California, trains only derail -- rockets explode, people need life support in space, planets other than earth are hell-holes...everybody will hate it on Mars, and other planets/moons in the solar system are only worse!
Reusable technology is the reason why Virgin Galactic can offer $250,000 tickets, and the price will come further down.
The following article sums it up quite nicely:Imagine if the way planes worked was that they took off, flew to their destination, but then instead of landing, all the passengers parachuted down to the ground and then the plane landed by smashing into the ocean and blowing up. So every plane flew exactly once, and to have a new flight happen, you’d have to build another plane.
A plane ticket would cost $1.5 million.
Bad analogy, rockets don't scale up easily -- can't grow the Falcon-9 architecture up to this size and re-use everything, it is so different -- 42 engines in the first stage of BFR (Big F**king Rocket) for about 28-million lb thrust...the Russians tried 30 moderate size 1st stage engines for 10-million lb thrust on the N-1 moon rocket and it was nothing but a disaster...vibration, acoustic and thermal issues, magnetic plasma eddy currents...it exploded every time!
Don't think you can easily computer model the stresses on this monstrosity, it is uncharted territory and he wants to launch people in a decade from now...And I don't want to hit below the belt...but two SpaceX Falcon-9 disasters in about a year...I like what SpaceX has done, but lets nail down the easier stuff before sailing off to other planets.
I am still disappointed in the adoring press -- at the end of the video during question time, all the reporters, male and female, were weak in the knees, gushing love for Elon. More skeptics are needed, the articles on technical sites were too optimistic as well. Before he takes investors and/or taxpayers for a ride to nowhere...or death for foolish ticket holders ...people should review the unanswered questions in detail...To me, his presentation this week was a pipe-dream at best, and a joke at worst.
A future post on more detailed technical non-starters for BFR, ITS, etc. -- e.g. refining methane on Mars for fuel, low risk, no worries -- still coming, stay tuned...