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by D Tibbets
Thu Sep 29, 2016 7:19 am
Forum: News
Topic: SpaceX News
Replies: 2283
Views: 500134

Re: SpaceX News

That three percent of launch costs is the fuel is true for traditional rockets. Reuse, especially high reusability with little turnaround costs elevates the fuel costs per mission as a percentage, though admittedly the fuel cost remains the same, but all other costs go down in relation. In commercia...
by D Tibbets
Wed Sep 28, 2016 10:12 pm
Forum: News
Topic: SpaceX News
Replies: 2283
Views: 500134

Re: SpaceX News

The video shows the transport entering atmosphere in a lifting body attitude and then smoothly transitioning to vertical retro propulsion. More complicated shapes and even seperations means more complexity and weight. Remember that a very good heat shield must protect each component. This adds even ...
by D Tibbets
Wed Sep 28, 2016 2:55 am
Forum: News
Topic: SpaceX News
Replies: 2283
Views: 500134

Re: SpaceX News

The chart three posts above is possibly obsolete. Back in 2010 the Merlin 2 was mentioned as a 1.7 million pound thrust kerosene/ oxygen engine. Since then I am not aware of any further development to an actual engine. My impression, is that instead of this, Space X is putting their money into metha...
by D Tibbets
Sun Sep 25, 2016 6:26 pm
Forum: News
Topic: SpaceX News
Replies: 2283
Views: 500134

Re: SpaceX News

The liquid helium tank in the second stage LOX tank apparently failed catastrophically. Just sitting on the pad! It will be quite interesting to understand if it was a sudden failure (most probable cause) or a constant leak that generated an unregulated over-pressure in the LOX tank (less likely). ...
by D Tibbets
Tue Aug 09, 2016 3:53 am
Forum: General
Topic: Freon moderated reactor
Replies: 15
Views: 5061

Re: Freon moderated reactor

As mentioned, radioactive heating even once the fission has stopped has to be handled. From my reading after the Japanese nuclear accidents, and from earlier reading, the post shutdown radiactive heating is about 10% of the heating with fission turned on. As such the heating of a propellant can only...
by D Tibbets
Fri Jul 22, 2016 2:03 am
Forum: News
Topic: SpaceX News
Replies: 2283
Views: 500134

Re: SpaceX News

"One tonne of fuel from 17 MWhr of electricity" ... I suppose large solar farms could provide for adequate fuel production in a timely manner. But a Bussard Polywell fusion reactor or one of it's competitors would be tremendously useful. And this is only for an energy source consideration....
by D Tibbets
Thu Jul 21, 2016 3:51 pm
Forum: News
Topic: SpaceX News
Replies: 2283
Views: 500134

Re: SpaceX News

SpaceX cannot establish a natural monopoly. Now that cheaper flight costs have been shown, others can eventually duplicate the work. If SpaceX attempts to increase costs too much, competitors will enter. The only way ULA style monopolies exist is with government interference. Well,to be fair, monop...
by D Tibbets
Thu Jul 21, 2016 6:42 am
Forum: News
Topic: Lockheed Skunkworks Announces Comm. Fusion in 4 years
Replies: 37
Views: 21251

Re: Lockheed Skunkworks Announces Comm. Fusion in 4 years

I resisted disparaging the significance of first plasma, but as T. Ligon said, it is trivial. It has little to do with the physics that you are pursuing. It is a trouble shooting step that merely means you have plugged the cord into the wall and managed to avoid blowing all of the fuses or burning t...
by D Tibbets
Thu Jul 21, 2016 6:34 am
Forum: News
Topic: SpaceX News
Replies: 2283
Views: 500134

Re: SpaceX News

Reuse and presumed savings from it allows for more profits for Space X or cheaper prices for customers. Or more reasonably, a combination of both. Higher profit margins allows for more growth and less aversion to risk. Lower prices to customers encourages a greater slice of the pie for Space X. That...
by D Tibbets
Wed Jul 20, 2016 11:17 pm
Forum: News
Topic: SpaceX News
Replies: 2283
Views: 500134

Re: SpaceX News

...... Musk has stated several times that their goal is rapid reuse. He once talked about flying a stage twice in a single day, but that is a very long term goal. Finally, people assume that SpaceX somehow wants to achieve maximum profit per launch. This is wrong. They want to achieve maximum progr...
by D Tibbets
Wed Jul 20, 2016 10:51 pm
Forum: News
Topic: SpaceX News
Replies: 2283
Views: 500134

Re: SpaceX News

The one use booster may cost 35 million. But the reusable booster now costs an arbitrary 210 million. Sorry, I might have missed it, but where does the 210 Million cost figure comes from for the SpaceX reusable booster? It seems to me an unrealistic figure from both, a material cost and a research ...
by D Tibbets
Wed Jul 20, 2016 4:26 am
Forum: News
Topic: SpaceX News
Replies: 2283
Views: 500134

Re: SpaceX News

Reusing a rocket is going to cost something in terms of initial stage construction cost or performance. How many reuses you need for reuse to make sense depends on how much extra it costs to build a reusable stage. By "conventional" lines of launch engineering a reusable stage costs a lot...
by D Tibbets
Wed Jul 20, 2016 4:08 am
Forum: News
Topic: SpaceX News
Replies: 2283
Views: 500134

Re: SpaceX News

The estimates above make one glaring assumption. As pointed out, the cost of building the initial booster that is recoverable must be more than a use once booster. There is also a payload to orbit penalty (this is a complex consideration as many missions may not utilize the entire lift to orbit capa...
by D Tibbets
Sat Jul 02, 2016 11:59 am
Forum: News
Topic: in the lifestyle section of the bangkok post ?
Replies: 10
Views: 5843

Re: in the lifestyle section of the bangkok post ?

Of more interest to me- the photo shows the relative scale of the WB8 magrid in relation to the vacuum vessel. Gaps, etc can be measured based on the assumption that the magnets have a major radius of 30 cm, that has been quoted in the past (I think).

Dan Tibbets
by D Tibbets
Sat Jul 02, 2016 11:39 am
Forum: News
Topic: Lawaranceville E-Newsletter
Replies: 826
Views: 280491

Re: Lawaranceville E-Newsletter

Link from the above: Avalanche proton-boron fusion based on elastic nuclear collisions https://www.researchgate.net/publication/303293228_Avalanche_proton-boron_fusion_based_on_elastic_nuclear_collisions Abstract Recent experiments done at Prague with the 600 J/0.2 ns PALS laser interacting with a ...

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