Earlier quoted context omitted.
Wow, he really knows how to push the right buttons... I suppose it helps to have a company you built with almost unfair price/technical advantages behind you.
Yes it was so easy
? I didn't say it was easy,..
SpaceX Successfully Soft-Landed Booster Rocket in the Atlantic
141–147 of 147 posts
Re: SpaceX Successfully Soft-Landed Booster Rocket in the Atlantic
#142Earlier quoted context omitted.
I said this in another thread, but part of the issue is failure intolerance. Sure - for human payloads I'd want to be damn sure my process is good, like, hundreds to thousands of missions deep before I trusted it. But that's totally unnecessary for an unmanned payload! If the cost of launch drops enough, you can fully justify launching 2x the payloads if you expect maybe 1 in 10 failures due to the mode of launch. I…
This is true for a sub-set of unmanned payloads. Space-X is great for the sub-set of things that don't require insurance, and don't therefore need to use corner-case mil-spec stuff with the corner case pricing. For others, the cost of losing a $1-2B bird on top of a $100m/cheap rocket is shitty math. Nobody is going to insure the top of it, so ultimately the "waste" is akin to a form of insurance. Everybody knows thi…
The $2B satellite is equally absurd, and only costs that much for the same reasons that the launch costs $400M. Everything is bespoke and produced in the maximal number of congressional districts, with no meaningful competitive pressure to drive prices downward.
And the two expenses buoy each other: if launches were inexpensive, you could spend a lot less on fault-tolerance in the payloads, because you could just launch a lot more payloads or even support on-orbit repair infrastructure.
Re: SpaceX Successfully Soft-Landed Booster Rocket in the Atlantic
#143Re: SpaceX Successfully Soft-Landed Booster Rocket in the Atlantic
#144Earlier quoted context omitted.
For Falcon 9 though, the first stage contributes so much of the dV that it is not particularly feasible to land it at the launch site - by the time it separates, it's moving at several kilometers per second away from the launch site towards the horizon. That opens up the question of where the launch/landing site pair is bound to be. A ship-based landing system, such as a semisubmersible oil drilling rig (only ~$1B us…
Citation? Usually the flight plan is to increase altitude (less atmospheric drag) before increasing angular velocity to full orbit. Elon's been pretty explicit that F9 stage 1 will land back on the pad, or very close by.
See this thread for estimates on the dV of the different stages of these launch platforms for a full-capacity payload:
http://forum.nasaspaceflight.com/index.php?topic=30685.0;all
It costs about 8km/s to get into low orbit from an atmosphere-less Earth. From our planet it costs about 9.4-1.0km/s because of aerodynamic and gravity losses. Those aerodynamic and gravity costs, and the Hohmann Transfer from groundlevel to orbit (trivial for LEO, more for GTO) are the only parts of the equation one can address while burning vertically to stay over the launch site.
Assuming 10, If the first stage only has to contribute 2km/s, it can address aerodynamic and gravity losses (while thrusting vertically), and then leave the second stage to boost for the horizon and achieve full orbit all on its own.
At 4-5km/s first stage contribution, it doesn't look like this is possible unless the payload is very undersized, leaving the second stage with enough dV to go from 'rising out of the upper atmosphere vertically' to 'circular orbit' all on its own.
The mass is a free variable, a greater vertical component is practical in GTO (and I don't have the modelling skills to say how much), and the second stage may launch fully fueled for F9R contra to the existing pattern, so I can't be 100% sure whether F9R will be a practical return-to-launchsite option for lightweight GTO payloads.
Re: SpaceX Successfully Soft-Landed Booster Rocket in the Atlantic
#145Earlier quoted context omitted.
Citation? Usually the flight plan is to increase altitude (less atmospheric drag) before increasing angular velocity to full orbit. Elon's been pretty explicit that F9 stage 1 will land back on the pad, or very close by.
See this thread for estimates on the dV of the different stages of these launch platforms for a full-capacity payload: http://forum.nasaspaceflight.com/index.php?topic=30685.0;all It costs about 8km/s to get into low orbit from an atmosphere-less Earth. From our planet it costs about 9.4-1.0km/s because of aerodynamic and gravity losses. Those aerodynamic and gravity costs, and the Hohmann Transfer from groundlevel t…
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Re: SpaceX Successfully Soft-Landed Booster Rocket in the Atlantic
#146Earlier quoted context omitted.
"Seems like the wrong time to be sending hundreds of millions of dollars to the Kremlin" -- Elon Musk He's certainly not making friends in Russia today. That said, I feel like the ISS is too important to be left to the whims of the US Congress. IIRC NASA plans to deorbit the American part of it within the next decade, while Russia keeps the rest aloft and turns it into a waystation for planetary missions.
Not many people know that he initially (pre-SpaceX) tried to buy a couple decommissioned ICBMs to send a plant to Mars. He was ready to write the check, and the Russians spiked the price at the last minute. So he's probably got a grudge or two.
I doubt it's a grudge. Accusing your competitor of sending money to the Kremlin in a time when the U.S.-Russia relationship isn't exactly great is simply a well-executed political jab.
Re: SpaceX Successfully Soft-Landed Booster Rocket in the Atlantic
#147Earlier quoted context omitted.
? I didn't say it was easy,..
pointing out an accomplishment as "unfair" without further elaboration serves to diminish it
I just meant unfair as in they have extreme advantages that almost no one else can replicate. That's an impressive accomplishment, I don't think it diminishes what they've done at all.