They want their craft to be able to land on any surface. Two of their chief product values are modularity and versatility.
I toured SpaceX HQ just yesterday and saw this video (or some of it). The employee presenting said that landing on Mars w/ a parachute is not a good option. Powered landing makes their craft able to land on any surface.
This is a paraphrase; and I am not a rocket scientist, so don't quote me on this.
This is certainly part of it. The powered landing will give them precision control to touch down right on the launchpad instead of having to pick up the assets at sea, saving lots of time and money. But it also allows for a module to land on the Moon or Mars. Mars has an atmosphere, but only with about 1% the density of Earth's, so for vessels with this scale of mass, parachutes aren't much use, besides the issue once again of being able to position your landing spot precisely. Supposedly at every design step where it's applicable Elon has opted to make everything as ready for Mars as possible.
Supposedly at every design step where it's applicable Elon has opted to make everything as ready for Mars as possible.
Absolutely correct. I got that vibe from all employees I listened to yesterday. The underlying motivation of the company is: to go to and colonize Mars. Everything they do before then is to gain credibility, survive, and fund R&D toward reaching their ultimate goal.
I work at NASA (though not on rockets), and that's a fair assessment; I think you correctly articulated what the SpaceX employee was telling you.
Aerobraking and parachutes alone aren't enough on Mars, even for small payloads (less than people-sized). Just look at the MER and MSL entry, descent, & landing systems. The reason being that mass scales with the volume while aerobraking and parachutes obviously rely on cross-sectional area. Even MSL, which is an order of magnitude lighter than a Dragon capsule, requires a sophisticated hybrid EDL system.
Also, although it may be Musk's goal to go to Mars, there is good profit to be made in Near Earth Objects and the Moon, none of which have much of an atmosphere to speak of.
I saw an interview where Musk said the rocket cost $50M to build but the fuel was about $100-200K so a few kg less to orbit would be ok if they could relaunch quickly.
but i did lol a little when i saw the legs push out from the rocket, when i think reusable i think drop it in the sea and have a boat go pick it up not land on the pad you just fired it from.
if this works out United Launch Alliance with Boing and the rest can just quit the rocket business, its like the intro to Patton "You know i actually pity those poor bastards we're going up against. By God, I do. We're not just going to shoot the bastards. . ."
For me the more pressing question is would I want to be in the capsule that uses parachutes for landing or rocket engines. My unscientific guess that using parachutes for landing humans is safer - one engine failure of eight (?) engines and capsule is off-course and crew is gone.
I suspect it would be designed so that the lose of one engine wouldn't cause it to crash, just like the lose of one parachute cord shouldn't cause other vehicles to crash.
I'd also be surprised if they did anything to foreclose the use of a parachute. If NASA or somebody else wants to eat the weight of a parachute as a backup, I doubt SpaceX will say no.
I'm assuming someone at Space X did at least some back of the napkin math, but color me skeptical.