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Re: SpaceX News

Posted: Thu Sep 06, 2018 12:20 am
by paperburn1
A brief test-firing of a Falcon 9 rocket Wednesday morning kept SpaceX on track for a launch Saturday night from Cape Canaveral with a communications satellite to be jointly used by Telesat and APT Satellite of Hong Kong.

The rocket’s nine Merlin 1D main engines ignited at Cape Canaveral’s Complex 40 launch pad at 10 a.m. EDT (1400 GMT) Wednesday after SpaceX engineers filled the two-stage Falcon 9 with a mixture of super-chilled kerosene and liquid oxygen.

so that is thirteen launched counting this one, and 25 that should be overall this year. By the estimates of my previous post they might break even this year. :D

Re: SpaceX News

Posted: Thu Sep 06, 2018 1:49 am
by Aero
a mixture of super-chilled kerosene and liquid oxygen.


A mixture - hmm - how does that work?

Re: SpaceX News

Posted: Thu Sep 06, 2018 9:08 am
by paperburn1
Aero wrote:
a mixture of super-chilled kerosene and liquid oxygen.


A mixture - hmm - how does that work?

LIKE THIS (did not even catch that from the article ) :lol:
Image

Re: SpaceX News

Posted: Mon Sep 10, 2018 4:51 am
by D Tibbets
FYI... It is not super chilled kerosene or a mixture until it is mixed in the engine combustion chamber (with a small caviet).
The fuel is a modified kerosene (distilled to a more consistent mixture of hydrocarbones called JP1 fuel) and this is near room temperature. The seperate oxygen is superchilled- that it is not at the typical liquid oxygen temperaure as used in other rockets- at or just below the boiling temperature. It is cooled further to just above the solid- liquid transition temperature. This super chilled liquid oxygen is a little more dense so the same size tank can hold a little more propellent (oxydizer in this case.

The caviet is that the turbopumps are driven/ powered by adding fuel rich (I think) mixture of fuel with a relatively small proportion of oxygen. This is ignited and burns to the exaustion of the oxygen supply injected. This produses hoit combustion product gasses that drive the turbine. This in turn spins pumps that feed cold liquid fuel and oxydizer seperatly to the engine combustion chamber. Why and how these mixtures are chosen are a part of the rocket science that allow for an engine that can consume lots of propellant and generate lots of thrust without the most sensitive components melting or failing in an explosive manner.

Dan Tibbets

Re: SpaceX News

Posted: Mon Sep 10, 2018 12:48 pm
by ladajo
The TELSTAR-18 mission was successful <yawn>.
Although they lost points on the 1st Stage landing, more off center than usual I think (Judges give it 9.2)

Let's see how fast they recycle this booster for flight again.

Re: SpaceX News

Posted: Mon Sep 10, 2018 5:34 pm
by Maui
Was surprised to see next on the agenda isn't until Oct6. I had thought things were supposed to be packed in pretty tight this month to the end of the year.

Re: SpaceX News

Posted: Mon Sep 10, 2018 8:18 pm
by choff
Calls for a little celebration :D


https://www.youtube.com/watch?v=4B7ypA1fSwU

Re: SpaceX News

Posted: Tue Sep 11, 2018 2:25 pm
by Skipjack
Maui wrote:Was surprised to see next on the agenda isn't until Oct6. I had thought things were supposed to be packed in pretty tight this month to the end of the year.

My guess would be that the delay of Commercial Crew DM1 to November and DM2 to next year has something to do with it. The rest might be space craft readiness issues.
Also LC39A is currently down for installation of the crew arm and preparation for DM1 and DM2.
So far SpaceX is planning 11 more launches for this year, but some most likely will slip into next year:
https://forum.nasaspaceflight.com/index ... ic=43418.0

Re: SpaceX News

Posted: Fri Sep 14, 2018 5:13 pm
by Maui
An exciting update to break the tedium of successful launches today!

Moon trip passengers (via BFR) to be announced Monday. Included is a render of an updated BFR design:
Image

All engines now look to be sea-level. Speculation is that the skirt around the bottom of the fuselage may form a secondary bell for vacuum efficiency. Would that work?

Re: SpaceX News

Posted: Sun Sep 16, 2018 4:39 pm
by Skipjack
Maui wrote:An exciting update to break the tedium of successful launches today!

Moon trip passengers (via BFR) to be announced Monday. Included is a render of an updated BFR design:
Image

All engines now look to be sea-level. Speculation is that the skirt around the bottom of the fuselage may form a secondary bell for vacuum efficiency. Would that work?

I have seen it. I am not sure about the petal- bell thing. The pedals would have to extent out further in order to have much of an effect. The shape is peculiar though and so is the fact that all engines are now clustered more closely together to make room for this thing whatever it is. It could be a kind of heath shield. Though the gaps are puzzling.

Re: SpaceX News

Posted: Tue Sep 18, 2018 3:29 am
by Maui
Disappointed by updated design. Turns out the only significant difference (added fins) were not a result of engineering, but simply that Musk liked the aesthetics more. He even admitted the design was now riskier as a result.

This guy legit scares me now.

Re: SpaceX News

Posted: Tue Sep 18, 2018 12:54 pm
by TDPerk
Maui wrote:Disappointed by updated design. Turns out the only significant difference (added fins) were not a result of engineering, but simply that Musk liked the aesthetics more. He even admitted the design was now riskier as a result.

This guy legit scares me now.


It legit scares me you spread FUD so easily, and you're full of it.

"The central fin has nothing to do with directional stability and control, and serves as a symmetric location for the third landing strut."

Re: SpaceX News

Posted: Tue Sep 18, 2018 1:13 pm
by Maui
“Prior to this the idea was to decouple the legs from the wings. This wasn’t very aesthetic, so now we have 3 large legs/wings that actuate. It is slightly more risky because we are combining multiple functions together”

Re: SpaceX News

Posted: Tue Sep 18, 2018 3:40 pm
by TDPerk
Maui wrote:“Prior to this the idea was to decouple the legs from the wings. This wasn’t very aesthetic, so now we have 3 large legs/wings that actuate. It is slightly more risky because we are combining multiple functions together”


Don't care what you choose to fixate on, or details you care to invent for yourself. It is slightly more risky from the isolated standpoint of the fins alone, more jobs is more risk. It lowers risk from teh standpoint of the vehicle, because you dan't have a more complicated aeroshell

Re: SpaceX News

Posted: Tue Sep 18, 2018 5:45 pm
by Maui
Who is inventing details? Do you have a good reason to know Musk is wrong when he states the new design is riskier?

Aside from that, I'm trying to work out your ground rules here... quotes irrelevant to my point are preferable to ones that spell out my concern almost verbatim? Is there some further guidelines to knowing which statements Musk makes I should ignore? (outside of who is and isn't a pedophile)

I would think most would agree it's pretty startling that Musk would take an extremely ambitious and risky project and make it even riskier (even if just a little) in the name of aesthetics. In light of some of the other questionable choices Musk has made recently, I'm not sure I'm on his page. I'd much rather have a design that has the best chance of working rather than something that, as Musk puts it, "looks like the Tintin rocket design". I want a moon rocket. I want a Mars rocket. I want to fly to Sydney in an hour. To heck with Tintin....