SpaceX (general discussion)

[Michel Van]

ITF-9 at 4 until 7 April 2025 ?
Seems SpaceX aims for monthly launches monthly
more information here

View: https://www.youtube.com/watch?v=p2imCb8HMfs

 

[FighterJock]

Fingers and Toes crossed that Starship Flight 9 does not explode this time Michel Van. Let's see if SpaceX has mannaged to sort the issues that plagued the last test launch.

 

[sferrin]

Fingers and Toes crossed that Starship Flight 9 does not explode this time Michel Van. Let's see if SpaceX has mannaged to sort the issues that plagued the last test launch.

It is interesting that they seem to have got the "hard" part figured out (catching a booster) but Starship is taking longer. Then again, considering what it's being asked to do, it makes sense that it would. Once they get it figured out though, and they will, oh boy are things going to get interesting.

 

[Michel Van]

Fingers and Toes crossed that Starship Flight 9 does not explode this time Michel Van. Let's see if SpaceX has mannaged to sort the issues that plagued the last test launch.

it depends if they get the POGO issue under control.
but i fear that those hardware modification happens from Starship 36 onwards,
and IFT-9 is launch in hope to get 35 close to Orbit.

 

[sferrin]

it depends if they get the POGO issue under control.
but i fear that those hardware modification happens from Starship 36 onwards,
and IFT-9 is launch in hope to get 35 close to Orbit.

Do we actually know it's a POGO issue? Has SpaceX said as much?

 

[Michel Van]

Do we actually know it's a POGO issue? Has SpaceX said as much?

They talk during countdown of IFT-8 about oscillation and Harmonic frequency in feed lines aka POGO

But it could also be ice that forms inside Methane feed line as pass true LOX tank.
and this methane Ice get into Turbopumps...

 

[publiusr]

The name of the SpaceX capsule recovery vessel that pulled crew-9 out of the drink is "MV Megan," which was made in Alabama.

One of two, as per the wiki.

-----------------------
On the Starship front...

Isar is to go with the Hank Hill favorite propane, somewhere between methane and RP (I have heard it described by Brian in the comments section at Space News' article on Isar):

"10% heavier than methane per BTU, but 3 times denser, so fuel tanks could be 1/3 smaller."

Any reason for Elon not to use that hydrocarbon? Less steel, less draggy surface area...

 

[Byeman]

The name of the SpaceX capsule recovery vessel that pulled crew-9 out of the drink is "MV Megan," which was made in Alabama.

One of two, as per the wiki.

And how is that relevant?

Isar is to go with the Hank Hill favorite propane, somewhere between methane and RP (I have heard it described by Brian in the comments section at Space News' article on Isar):

"10% heavier than methane per BTU, but 3 times denser, so fuel tanks could be 1/3 smaller."

Any reason for Elon not to use that hydrocarbon? Less steel, less draggy surface area...

Cost and easier to get. And propane can't be generated on Mars.

 

[BlackBat242]

So long, and thanks for all the fish !

Wot I was gonner say!

 

[BlackBat242]

Isar is to go with the Hank Hill favorite propane, somewhere between methane and RP (I have heard it described by Brian in the comments section at Space News' article on Isar):

"10% heavier than methane per BTU, but 3 times denser, so fuel tanks could be 1/3 smaller."

Any reason for Elon not to use that hydrocarbon? Less steel, less draggy surface area...

 

[Michel Van]

Any reason for Elon not to use that hydrocarbon? Less steel, less draggy surface area...

There is no propane on Mars
SpaceX want to use the mars C02 and Water Ice to make Methane to fuel Starship return trip.

one question, if propane has so much advantage, why is not used by rocket companies ?

 

[Grey Havoc]

one question, if propane has so much advantage, why is not used by rocket companies ?

It has been long seen as 'old fashioned' within the industry, I think.

 

[sferrin]

It has been long seen as 'old fashioned' within the industry, I think.

"Older" than kerosene?

 

[Firefinder]

I am struggling to think of any rockets that USED propane.

And a quick google search finds me nothing beside a quote of it having a lower specific impulse then methane.

So that the likely reason if anything...

 

[sferrin]

I am struggling to think of any rockets that USED propane.

And a quick google search finds me nothing beside a quote of it having a lower specific impulse then methane.

So that the likely reason if anything...

And considering the stuff they've tried over the years, I'd think there must be something about propane that causes everybody to steer clear. Though I don't know what that might be off the top of my head.

From "Ignition!"

"Two space-storable systems have been investigated rather intensively. RMI and JPL, starting in 1963 or so, and continuing into 1969,
worked out the diborane-OF2 system, while Pratt and Whitney, Rocketdyne, and TRW, with NASA contracts, as well as NASA itself,
have concentrated their efforts on OF2 and the light hydrocarbons: methane, ethane, propane, 1-butene, and assorted mixtures of these.
(In most of their motor work, they used a mixture of oxygen and fluorine as a reasonably inexpensive surrogate for OF2.) AU the hydrocarbons were good fuels, but methane was in a class by itself as a coolant, transpiration or regenerative, besides having the best performance. The OF2-methane combination is an extremely promising one. (It took a long time for Winkler's fuel of 1930 to come into its
own!)"

 

[NMaude]

OF2 (Oxygen Diflouride) would have to be a very dodgy oxidiser to handle.

 

[martinbayer]

View attachment 763571

View attachment 763572

“Taste the meat, not the heat!”

 

[Michel Van]

Updates

View: https://www.youtube.com/watch?v=TliqyYEIl4s

 

[abheiden]

I am struggling to think of any rockets that USED propane.

And a quick google search finds me nothing beside a quote of it having a lower specific impulse then methane.

So that the likely reason if anything...

There was the CXV Quick reach 2 Booster proposed by T/Space in 2004.
it has to be a air launched propane pressure fed 2 stage rocket.
It do even subscale drop test together with Burt Rutan.
They offer the CVX capsule with 4 people to the ISS for 20 million If you must believe that.

 

[publiusr]

Starship can keep the methane for ISRU.
If SuperHeavy used propane, might that reduce slosh? No ISRU considerations for first stages.

Starship needs methane to also serve as a coolant.

 

[Byeman]

Starship can keep the methane for ISRU.
If SuperHeavy used propane, might that reduce slosh?

No. Then the vehicle will have to have two different engines, additional GSE and tanks, different loading processes, etc
Propane will have more slosh issues since it is more dense

 

[TomcatViP]

9 days Turnaround for Falcon Booster:

A Falcon 9 rocket lifted off from California's Vandenberg Space Force Base Friday at 2:49 a.m. EDT (0649 GMT; 11:49 p.m. on March 20 local California time), on the NROL-57 mission for the U.S. National Reconnaissance Office (NRO).

This rocket's first stage also lofted the SPHEREx space telescope and PUNCH solar probes for NASA on March 11, according to a SpaceX mission description. NROL-57 was therefore the booster's second launch in a little over nine days, besting the previous Falcon 9 turnaround record of 14 days.

SpaceX sets new rocket-reuse record on launch of US spy satellites (video)

A Falcon 9 first stage flew for the second time in just nine days early Friday morning (March 21).

www.space.com

 

[sferrin]

No. Then the vehicle will have to have two different engines, additional GSE and tanks, different loading processes, etc
Propane will have more slosh issues since it is more dense

Do you know why propane doesn't appear to have been used as a rocket fuel?

 

[Michel Van]

Far well Highbay
it's demolition began