My thoughts on Elon Musk's plans for a Mars missionHyperloop and high-speed tunnel-boring:

Mission to Mars vs Earth's oceans
I was a big fan of Elon Musk (before his stupidity on Twatter led to this slander plus this flamethrower nonsense and SEC action for poor corporate governance!) - or at least his world-changing/saving Tesla electric cars & SolarCity companies (although I'm afraid his solar roof tiles are only going to be viable for people who highly value aesthetics) - and I still think his reusable, self-landing Space-X technology is impressive, at least if used for sensible things like satellites & earth-orbit space stations (less so as an alternative to long-distance aviation)...
- and even more so if Elon really believes we're actually living in a simulation which IMO tops the scales for crazy-mad bonkers and is hardly worth critiquing - because then why bother saving us?!
Have you really thought this one through Elon?  Even if living on Mars can be made technically and economically feasible (which is highly doubtful), who's going to leave Earth to live on Mars before the meteor strikes?  Will you have umpteen rockets and willing people on stand-by, like in James Bond's Moonraker?  Is this actually a plan to save the human race by raising the average IQ of those of us remaining?!  Or if you wait until a meteor strike is almost certain & imminent, I can't imagine a very orderly evacuation process happening!

If it's worth having any such survival plan for the human race (& I'm not sure it is), why go to Mars if you could instead convert Hyperloop (or other transport) tunnels into eco-living refuges?  
Tunnels under the sea bed should be rigid, have a stable temperature and access to water, seafood, power (from ocean currents) and sewerage, and not least, have an economic purpose before a meteor strikes!
For a transformative transport link / backup disaster refuge, I'd consider using under-sea sections of a Japan to China Hyperloop along this route: Tokyo-Nagoya-Osaka-Hiroshima-Fukuoka-(Nagasaki-Shanghai: <2 hrs from Tokyo)-Seoul-Beijing (<3hrs from Tokyo).

I notice though that in a later TED talk Elon made no mention of saving earth from a meteor strike to justify his Mars mission.  I suspect the "saving humanity" thing was actually just an attempt to post-rationalise what is really just motivated by the excitement of inter-planetary travel.  But if the true purpose is just to explore, then as David Attenborough says in Blue Planet II, we know more about the Moon & Mars than we do about the oceans that cover 70% of Earth's surface & hold 97% of all the water in the world.
When there's so much we don't know about ourselves and own planet, then if the motivation is being inquisitive - to discover the unknown - then I say we should focus on Earth!

For those who've missed all the hype/news about it, "Hyperloop" is a potential "fifth mode of transport" that would propel levitated pods through evacuated tubes at around 1,200kph (close to the speed of sound).
A conceptual design was suggested by Elon Musk in 2013 (see here or here), and the rate of development (at least in the claims from various groups raising finance!) appears as astonishing as the technical & economic potential:
But is the Hyperloop all hype? To some extent, yes, because none of the 'protoypes' I've seen (in the links above) look like they combine everything that's needed to make the design a technical & economic success. And Hyperloop has its critics, e.g. see this deeply skeptical video, although I think some of the arguments in this are misplaced (e.g. turbine compression wasn't Elon's main proposed source of thrust) and though other critiques in it are valid I think there are solutions.
Personally I think the construction of test tracks by Hyperloop-One and SpaceX are encouraging premature and not particularly useful building activities, which distract from the design and modelling work that's needed at this stage of development.
But I do think there's a reasonable chance Hyperloop could ultimately be made to work, and have done my own Sydney-Melbourne route analysis (see this xls on my Sydney Metro & HST page) and can send my confidential technical Hyperloop design to serious investors on request (via LinkedIn).


The Boring Company
Fed up - like the rest of us - with being stuck in traffic, Elon Musk suddenly announced he was setting up The Boring Company to figure out how to improve the speed & efficiency of tunneling by a factor of ten, and then he was going to just start digging tunnels under LA for cars to drop down into from surface level and speed through underground on "skates".
Like many reactions on Twitter, my initial thought was that this was a crazy idea and even somewhat arrogant to think one could so easily improve on current tunnel-boring technology, but then I was reminded of Einstein's quote, "If at first the idea is not absurd, then there is no hope for it", and I thought, "Well, this is Elon Musk, so maybe it is possible" (before I realised I needed to be more sceptical about some of his claims, like those in relation to autonomous cars and imminent self-driving Teslas).
And though I'm doubtful about the economic viability of extensive tunnels for low-capacity car-based systems, it would certainly benefit the safety, economics and design flexibility of Hyperloop or other tunnelled transport systems, as noted by Elon Musk in this TED talk.

So - before I saw his TED talk - I started to think about how tunnelling might be so drastically improved, and after looking at existing Tunnel Boring Machines (TBMs) I thought, "Wow, I can't imagine a more inefficient way of tunnelling!". These things grind their way through an entire face of rock at once, pulverising it and spewing it out the back as slurry. The enormous force needed to do this (over 60 Mega-Newtons) requires power in the order of 8 MW applied to 14.4m diameter cutters rotating at only about 1 RPM and progressing forward at only 20 metres per day (1.4cm per minute or 0.2mm per second).
Since the entire face of the tunnel is being cut away at once, there's limited-sized gaps in the cutting-head wheel for spoil to pass through, and so everything has to be pulverised into small bits - 'catch 22' (or vicious circle!). Moreover, it seems there's also a tricky process involved in managing slurry pressure at the cutter head, at least in soft ground TBMs.

Well, whilst I admit I know precious little about mining or geological engineering, I would have thought the obvious way to tunnel would be a mechanised version of how you would do it by hand - chip away around the circumference of the tunnel edge and then hack out the biggest boulders you can in one go (as long as you can still then carry these away).
So a machine version would start with something like a hole saw drill-bit on a very large scale:
If the same cutting power is applied to a much smaller area, the cutting force and speed can be much greater (in the same way a normal drill bit or chisel works).
Imagine then 3 concentric cutting rings like the one above, with the outer one having a radius of say, 2m (giving a tunnel diameter of 4m, which is a bit bigger than the 3.56m diameter of many London Underground tunnels), a middle cutter with a radius of about 1.75m and an inner cutter with a radius of about 0.75m. Actually each of these three cutting rings would consist of two concentric cutters with a spacing between them of about 2cm for slurry to be sucked back through.
The resulting cutting area would be 290 times smaller than the cutting area of the 14.4m-diameter TBM referenced above, and therefore it seems likely that with the same power unit, the blades could spin and cut forward faster by a similar magnitude. This video of a paper cutting-disc (also on Facebook) shows how much difference a high rotating speed makes!
Having cut into the rock a couple of metres, the middle and inner cutting rings would be retracted (the outer one staying to support the tunnel until concrete walls are built), leaving an outer ring of rock of 25cm thickness extending about 2m long into the tunnel. Being cantilevered at the deepest cutting point, it would probably break off under its own weight (or with not much of a tap). This ring of rock would then be dragged out by mechanical arms inserted where the middle cutter was (or they could be integrated into the middle cutting ring design).
Then, with a 25cm gap now available between the outer edge of the tunnel and the inner ring of 1 metre thick rock, more powerful robotic jack-hammers could be inserted to knock away the inner ring of cantilevered rock in large blocks, and then finally also the inner core of 1.5m diameter rock.
I would imagine this process could easily progress forward 25x if not 100x faster than current TBMs, i.e. in the order of 0.5 to 2km per day, which could make a high-speed train/Hyperloop from Melbourne to Hobart quite feasible (the longest tunnel section from Wilsons Promontory to Cape Portland in Tasmania via the islands of Hogan Group, Deal & Flinders would be 55km (equal to the longest sea bridge), so tunneling all sections from both ends in parallel could potentially be done in a month!).

Anyway, returning to the more proven world of Tesla, here's a link on the updated Masterplan (July 2016) for Tesla's mission for electric cars and solar power: http://futurism.com/elon-musk-just-released-teslas-master-plan-read-it-here/ and its 2020 goals.
I want a Model-3 !
Well I did, but I don't like their touchscreen being used for everything (even gears/direction!) plus I'm wary of their automated driving, and since I also don't have access to home charging, I'm quite happy with my Prius for now!