Author Topic: SpaceX: General Falcon and Dragon discussion (Thread 7)  (Read 348825 times)

Offline go4mars

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Re: SpaceX: General Falcon and Dragon discussion (Thread 7)
« Reply #40 on: 11/25/2012 06:37 pm »
SpaceX has the CCiCap contract to meet and is in competition with Boeing on this. Do you really see they can have a completely new Dragon ready in time?
They've certainly been thinking about capsules for a while now.  They may already have a paper design that they like.  If so, it may come together fairly quick.

And convince NASA to accept this complete turnaround?
NASA seemed unbothered by a change in rocket from V1.0 to V1.1.  Version 1.1 is in many ways a new rocket.  It even uses different engines.  Is that reasonable precedent? 
« Last Edit: 11/25/2012 06:39 pm by go4mars »
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Offline Jason1701

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Re: SpaceX: General Falcon and Dragon discussion (Thread 7)
« Reply #41 on: 11/25/2012 06:41 pm »
So regarding Dragons....

This is actually very obvious, and has been bugging me for a while.

SpaceX are very early to put up engineering development hardware on display (F1, F9, Dragon).

Also, once they started talking publicly about powered recovery of F9S1, Grasshopper was up in no time, and is now even flying.

They have Dragon, and they've been testing SuperDracos for quite some time now.

...  so where's Dragon 2?   There was a mockup on display, but nothing more.

I think all of this got reconciled when Elon said - "We didn't really know what we were doing with Dragon 1" and "Dragon 2 will look really cool", etc.

I think once Elon decides on a change in direction, he doesn't waste time on sunk-cost projects just because they're half-way through the engineering pipeline.

My tea-leaf reading from this is that the possibility that Dragon 2 has been greatly revised away from Dragon 1 + SuperDracos, and the conspicuously missing Dragon/Draco test-bed hopping around McGregor are in agreement here.



I appreciate your reasoning and I too stumble over that contradiction between Dragon 2 is the manned Dragon for ISS-access and it is completely different to the present cargo Dragon.

But SpaceX has the CCiCap contract to meet and is in competition with Boeing on this. Do you really see they can have a completely new Dragon ready in time?

And convince NASA to accept this complete turnaround?



SpaceX probably competed for CCiCap with this new Dragon, so NASA has already shown their approval for the changes.

Online meekGee

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Re: SpaceX: General Falcon and Dragon discussion (Thread 7)
« Reply #42 on: 11/25/2012 07:27 pm »
SpaceX probably competed for CCiCap with this new Dragon, so NASA has already shown their approval for the changes.
Heh, in that case, all we need to look for is that badly obfuscated PDF or PPT that's sure to be lurking somewhere in the NASA public archives
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Offline LegendCJS

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Re: SpaceX: General Falcon and Dragon discussion (Thread 7)
« Reply #43 on: 11/25/2012 07:33 pm »
Hi, everyone.
This is my first post on the forum, and I have a question.
Does anyone know, how much costs dragon capsule?

That is not public information. However, since SpaceX sells cargo delivery services to NASA at $133M per flight, and they advertise $54M for the Falcon 9, it must cost them less than $79M if they're profiting.

I was told by their head GNC engineer that they will do a flight of a refurbished/used dragon (rocket and all) for about $80 million.
Remember: if we want this whole space thing to work out we have to optimize for cost!

Offline LegendCJS

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Re: SpaceX: General Falcon and Dragon discussion (Thread 7)
« Reply #44 on: 11/25/2012 07:49 pm »
The Dragon appears to have had a few radiation issues on the last flight and from what I can tell from reading here it happened on one other occasion.  That seems a bit high even for commercial non rad hardened electronics.  Perhaps they were just unlucky, but there may be a bigger problem there.

The radiation environment in LEO is comparatively benign when you compare it to deep space or even the surface of Mars.  Any trip beyond LEO means traveling through the Van Allen Radiation belts and the radiation exposure there is hundreds of times greater than in LEO. 

This tells me that a rad hardened computer must be in the plans as I just don't see the current setup working for anything but LEO.

1) They experienced less radiation problems with their electronics than they expected (or designed for), so they consider themselves lucky, and their design to be quite robust to radiation. 

2) They know they will have to go rad-hard for Mars.

Its funny to keep seeing people bringing this up:

Its kind of like the whole  engine out discussion.  SpaceX built a system with multiple redundant components (9 rocket engines/ 3 computers with 2 independent cores each (with voting))  From day one the system was designed to be able to be robust to a problem or failure of one of those components (engine pressure release/ rad hit causing a reboot), and then the system flew and performed exactly as expected when the planed for even occurred. 

That is all that happened, but boy do people like to throw up heaps of concerns and warnings and calls for changes.

They will learn everything useful from these events and use the knowledge going forward, but they are optimizing for cost, not perfection.
Remember: if we want this whole space thing to work out we have to optimize for cost!

Offline RocketmanUS

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Re: SpaceX: General Falcon and Dragon discussion (Thread 7)
« Reply #45 on: 11/25/2012 07:59 pm »
Hi, everyone.
This is my first post on the forum, and I have a question.
Does anyone know, how much costs dragon capsule?

That is not public information. However, since SpaceX sells cargo delivery services to NASA at $133M per flight, and they advertise $54M for the Falcon 9, it must cost them less than $79M if they're profiting.

I was told by their head GNC engineer that they will do a flight of a refurbished/used dragon (rocket and all) for about $80 million.
80-54=26
$26M for a Dragon capsule sounds about right compared to some private jets. That would be in today's dollars. The difference between $80M and $133M is the start up costs and inflation. $80M is most likely the base price and added cost would be added for the specific mission per flight.
« Last Edit: 11/25/2012 08:09 pm by RocketmanUS »

Offline Mongo62

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Re: SpaceX: General Falcon and Dragon discussion (Thread 7)
« Reply #46 on: 11/27/2012 04:18 pm »
I found that article quite interesting.  I wish there were similar articles for every F9 and Dragon component made by outside manufacturers.

Offline mlindner

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Re: SpaceX: General Falcon and Dragon discussion (Thread 7)
« Reply #47 on: 11/27/2012 05:13 pm »
I found that article quite interesting.  I wish there were similar articles for every F9 and Dragon component made by outside manufacturers.
There are actually a bunch of these I've seen. They show up on google news with little fanfare. Two more (and there are more if I could find them again):
http://www.plm.automation.siemens.com/en_us/about_us/success/case_study.cfm?Component=30328&ComponentTemplate=1481
http://www.altium.com/successes/testimonials/aerospace/en/spacex.cfm
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Offline Mongo62

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Re: SpaceX: General Falcon and Dragon discussion (Thread 7)
« Reply #48 on: 11/27/2012 07:30 pm »
Robust Servo Motors Survive Launch Conditions to Optimize Rocket Fuel Burn
http://www.micromo.com/application-case-study-space-x-shuttle-launch.aspx

Some quotes from the article I found particularly interesting:

Quote
The first stage features nine engines that burn for approximately three minutes, and the second stage includes one engine that burns for approximately seven minutes. Because of the duration of the burn for each stages, the control loops can actually run relatively slowly. “The whole valve doesn't necessarily need to be fast,” says [Juerg Frefel, Avionics Engineer at SpaceX]. “It's a closed-loop system, which means that the command to the valve is to go to a certain angle. The outer loop adjusts the angle of the valve and the inner loop keeps the position steady in case it gets pushed around [by shock/vibration].”

Quote
Rocket engines produce heat as well as vibration, but contrary to what a person might think, thermal management does not pose a significant challenge in this application.

Much of the heat is radiated and is reflected away. In addition, given the relatively brief duration of the stages, the unit’s thermal mass makes it resistant to rapid temperature swings. “The actuator still has three to four pounds of mass, which means that in three minutes it doesn't heat up that dramatically,” Frefel says.

Quote
To control cost and production timelines, the SpaceX philosophy is to try to work with stock components whenever possible. Nothing special was done to the MICROMO motors to ruggedize them for the application; the design team simply ordered standard products.

From the Siemens link:

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SpaceX has modeled the entire Falcon 1 and Falcon 9 rockets and the Dragon capsule in NX. The software has no trouble handling more than 25,000-part assemblies. “Having the ability to work with an assembly of such size in a timely manner is very important,” says Thompson. “The entire assembly takes only five to 10 minutes to load.” Once loaded, a virtual mockup of the rocket enables designers to readily find interferences. A major benefit in working with large assemblies is “designing in context,” which allows various component parts to be developed and completed all while working in the assembly. Designing in context means immediate feedback relative to fit and feasibility. Conversely, without the ability to load all the relevant components around the area of concern, designing the components to fit precisely is a much more difficult and time-consuming task. In addition to NX’s assembly strengths, SpaceX designers use NX to simulate motion, such as the separation between the first and second stages, to further check their work.

SpaceX leverages its NX data in other ways as well. Technicians on the shop floor look at NX models as they build the rocket to better understand a rocket’s inner workings. This is particularly helpful for seeing the routes of tubes and wires within the rocket, for instance.

From the Altium link:

Quote
To ensure its launch vehicles always perform at this extraordinary level, SpaceX develops many of its boards and controllers under the fault–tolerant discipline. This time consuming engineering technique ensures that all systems can continue to operate despite a given component failing. Controllers and PCBs are fitted with additional components and back-up mechanisms for greater reliability.

Quote
Altium’s live design capabilities mean that the simplest modifications are automatically adjusted in all previous board and schematic work. The result: a flexible but reliable development and documentation process for SpaceX’s catalogue of PCB designs. Altium’s comprehensive libraries were found to be one of the biggest development boons for SpaceX. The library feature provided engineers with the latest and most up-to-date components in a user-friendly system. Engineers were also able to add new components, which allowed for greater customization and board enhancements.

Quote
Since introducing Altium Designer into its development process, SpaceX has enjoyed considerable improvements in its productivity. Without prior knowledge of the software, engineers were easily able to complete designs without the usual rigorous training required from separate or loosely integrated tools. Within just two weeks of applying Altium technology, engineers were able to create a power distribution and regulation board. This trend has continued. SpaceX has found its project turn over has increased exponentially.
« Last Edit: 11/27/2012 08:14 pm by Mongo62 »

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Online ugordan

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Re: SpaceX: General Falcon and Dragon discussion (Thread 7)
« Reply #50 on: 11/28/2012 07:59 am »
http://www.wacotrib.com/blogs/staff/joescience/About-last-nights-SpaceX-test.html

SpaceX conducted two single engine tests last night, of the Merlin 1D engine and the Merlin vacuum engine.  The tests were three minutes apart, just before 10PM.

They probably do these tests daily, but what I found interesting is these two separate tests only minutes apart.

Offline Ben the Space Brit

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Re: SpaceX: General Falcon and Dragon discussion (Thread 7)
« Reply #51 on: 11/28/2012 09:55 am »
They probably do these tests daily, but what I found interesting is these two separate tests only minutes apart.

Well, unless there are technical or practical reasons not to do so, I suppose sticking tests close together to reduce the noise nuisance is being a good neighbour.
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Offline Comga

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Re: SpaceX: General Falcon and Dragon discussion (Thread 7)
« Reply #52 on: 11/28/2012 03:33 pm »
Posting here where it is less "off topic"

From http://shitelonsays.com/transcript/elon-musk-lecture-at-the-royal-aeronautical-society-2012-11-16

Just the url of this website had me laughing to the point where a passing coworker wondered what was so funny.  I love it. 

In a world obsessed with carefully scripted talking points Elon "walks the walk and talks the talk".  You don't have to agree with all or anything he says, or believe a word of it, but I think you have to admire the guy.
What kind of wastrels would dump a perfectly good booster in the ocean after just one use?

Offline Lars_J

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Re: SpaceX: General Falcon and Dragon discussion (Thread 7)
« Reply #53 on: 11/28/2012 03:36 pm »
That is a great site! :D

Offline Elmar Moelzer

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Re: SpaceX: General Falcon and Dragon discussion (Thread 7)
« Reply #54 on: 11/28/2012 03:37 pm »
Quote
In a world obsessed with carefully scripted talking points Elon "walks the walk and talks the talk".  You don't have to agree with all or anything he says, or believe a word of it, but I think you have to admire the guy.
I think that Musk is a horrible speaker, but one can see that he is talking without a script and that makes him appear much more genuine, believable and likeable.

Online meekGee

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Re: SpaceX: General Falcon and Dragon discussion (Thread 7)
« Reply #55 on: 11/28/2012 05:23 pm »
That's a curious definition of "horrible".   Unconventional maybe?
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Offline Elmar Moelzer

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Re: SpaceX: General Falcon and Dragon discussion (Thread 7)
« Reply #56 on: 11/28/2012 05:33 pm »
Well, he studders a lot and has lots of uhhm and hmms in it, when he speaks that is what I mean. Lets say that "people would generally characterize him as a bad speaker", but I think it makes him appear more genuine and credible than someone who clearly practiced every word in front of a mirror.

Offline ArbitraryConstant

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Re: SpaceX: General Falcon and Dragon discussion (Thread 7)
« Reply #57 on: 11/28/2012 06:27 pm »
That's a curious definition of "horrible".   Unconventional maybe?
Unconventional suggests he's good at it but not in the traditional manner. I think it's more the case that he's just not that good.

Mitigated by the fact that he's extremely smart and well informed, and doing interesting stuff.

Offline Kharkov

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Re: SpaceX: General Falcon and Dragon discussion (Thread 7)
« Reply #58 on: 11/29/2012 12:30 am »
This might have been covered elsewhere (couldn't find it) but I remember, a few years ago, people were talking excitedly about Kwajalein Atoll as a wonderful place for SpaceX to launch from, what with it being only 8 degrees north.

I know they launched the Falcon 1 from there but suddenly, even with a bursting order book, there's no mention of the Atoll even with the benefits of launching from that close to the equator.

Any thoughts?
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Offline Robotbeat

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Re: SpaceX: General Falcon and Dragon discussion (Thread 7)
« Reply #59 on: 11/29/2012 12:40 am »
This might have been covered elsewhere (couldn't find it) but I remember, a few years ago, people were talking excitedly about Kwajalein Atoll as a wonderful place for SpaceX to launch from, what with it being only 8 degrees north.

I know they launched the Falcon 1 from there but suddenly, even with a bursting order book, there's no mention of the Atoll even with the benefits of launching from that close to the equator.

Any thoughts?
It turns out, logistics sucks for an island in the middle of the ocean far away from civilization. Also, Falcon 1 is barely worth it and the island would be too crowded to launch a Falcon 9 from, realistically. Lots more reasons, too.
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