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Sweet.

Those programs are always spiraling ... SM-6 is newish and I don't know nuttin about nuttin.  Like Sargent Schultz from Hogans Heros would say.... I know nothing.  Think Socrates said that too.

Somebody needs to scale up SM-3 / SM-6 for destroying asteroids, bolides and meteors on a short time response. 

Purely hypothetical, an asteroid interceptor would need to be a huge system.  If we could just strap about nineteen Atlas V heavys together.... something ridiculously bizarre looking would probably work.

I really believe there are greater threats from natural disasters than military threats. 

These are the vehicles and concepts worthy of model rocket design legend and lore.  Anice afternoon BBQ picnic for everyone to enjoy would work too.
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SpaceX General Section / Re: SpaceX fundraising again
« Last post by meekGee on Today at 06:15 AM »
Unfortunately for the discussion on this thread, there appears to have been an oopsy on the reported fund raising and 10 billion valuation.

I refer you to my post up thread-#51.

Party spoiler!

And add option D to my list above:
D) This has all been a dream

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One reason Im interested in long term health in pure oxygen (and low pressure) is the Moon. Oxygen is the one volatile it has in abundance. I hate the idea of leaking nitrogen all the time.
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Attached is a graph from my simulation showing down range distance for the final 20 km descent. Of course it is for standard atmosphere with no wind or weather. I expect the jet stream would make a noticeable perturbation in the down range distance but modeling it is beyond me.

So 6 km sideways for 20 km altitude - due to the remaining horizontal component of the trajectory, as simulated by you, and not including any dV imparted during the reentry burn.

How long does it take (in your simulation) to cross these 20 km?   About a minute?

The question is - what is the variance on that due to wind?  Suppose the wind imparts a 60 km/hr velocity to the stage (!).  That will move the impact point by 1 km.

This is assuming that we don't pre-know the wind condition (even though we flew through that region only a few minutes beforehand)

Can the fins null any unpredictable wind effect?   Can they cause the stage to tilt so that it generates enough side thrust to counter the wind effect?  This is what SpaceX is trying to demonstrate.

I think with a few more flights, they'll have all the data to show how much the returning stage is affected by wind, how well they can predict it ahead of time, and how much cross-range the fins give them.
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SpaceX General Section / Re: SpaceX fundraising again
« Last post by Scylla on Today at 05:41 AM »
Unfortunately for the discussion on this thread, there appears to have been an oopsy on the reported fund raising and 10 billion valuation.

I refer you to my post up thread-#51.
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While this narrative is true, it's a pipe dream to think another (NASA) flagship launch system would be any cheaper. The hand writing was on the wall when Obama "wanted to visit an asteroid by the mid 2020s."
Im not really sure Im reading you correctly. The point should of course be to avoid trying to solve the problem with another flagship launch system, right? This might be the obvious fact you are pointing out.

An asteroid mission does not need any particularly well defined delta v. You can always visit a dust grain. What it needs is detection of as many candidates as possible, a DSH that we are have achieved great confidence in years before a specific target is chosen, and great confidence that your rockets will work after many days in space to return you home.

Most importantly, the goal was ultimately capabilities, not an asteroid. Sure, depots (little more than existing upper stages) are not absolutely proven. Maybe a gamble on them might mean you somehow miss an asteroid deadline. That lesson would be more important than the visit. We need that technology. No single HLV launch will get us to mars. Anyway, we need long term fuel storage to get home.  It would just reveal how idiotic we would have been to avoid learning of our total incompetence here till a decade or two later. Oops, turned out we have to redevelop our infrastructure from scratch around methane instead of hydrogen, or hypergolics or SEP.
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SpaceX General Section / Re: SpaceX Acronyms and Nomenclature
« Last post by meekGee on Today at 05:36 AM »
My proposal is that Shanoson will keep the lead post updated based on inputs from down thread.
If acronyms are date-sensitive, maybe add the date at the end of their line.

And am I mistaken, or was "RUD" used by SpaceX?

They also had acronyms for their control centers, sometimes used during the webcasts, but I forget what they were.

Also, SPAM, and PICA-X

There was also Dragon Eye, and there was another sensor that had an acronym.





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Commercial Crew Vehicles / Re: SNC Dream Chaser UPDATE Thread
« Last post by docmordrid on Today at 05:36 AM »
Looks like it is official, they are changing to liquid motors.

http://www.parabolicarc.com/2014/08/19/snc-abandons-hybrid-motors-dream-chaser/#more-53194

The comments got interesting. Wasn't there a recent tweet or story that the liquid engines and thruster s would use the same fuel? Earlier reports put the thruster as using ethanol, but apparently not now. And it's the Vortex.

Quote
Terry Stetler 5 hours ago
The next question is what engine cycle, if pressure fed, or if it'll be ORBITEC s Liquid Vortex. Other sources say ethanol based. The speculation light is on.

Charles Lurio  @Terry Stetler an hour ago
No, it's off. The fuel is propane, the system is Orbitec's Vortex.
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SpaceX General Section / Re: SpaceX fundraising again
« Last post by meekGee on Today at 05:30 AM »
Why is the NASA/CRS deal one-off?  CRS-2 is coming as is CCtCAP. NASA science payloads are on the horizon.

A valuation is about growth. It's about the multiplier of investment to return. It's about saying "if you had X more money, what would you do to produce Y more return". It's really hard to make the argument that SpaceX could get more government business if only they had more production capability. Whereas commercial customers are lining up for it - if SpaceX can finally demonstrate they can deliver.

So we seem to have a the following situation:

A number of rather successful investors think one thing, and QG thinks another.

There are three explanations:
A) QG is correct about the investors being irrational with their money by a good order of magnitude, or
B) The model for valuation used by the investors is more forward looking than QG's, or
C) The investors have been given some information by SpaceX that makes then subscribe to the $10B valuation.

Shall we start a poll?
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SpaceX General Section / Re: SpaceX fundraising again
« Last post by Norm38 on Today at 05:12 AM »
So, has SpaceX found a successful "repeatable and scalable business model"?

When they re-fly a first stage they will. A lot of that $10 Billion must be counting on reuse panning out.
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