SpaceX Tuesday...

[MartG]

Eric Mc said:

I wonder why this issue took so long to manifest itself? Was there something a bit different about the conditions surrounding the helium tank pressurisation on the day of the explosion?

Or just chance that THIS time the tank failed, whereas previously if the fault occurred it didn't cause the tank to rupture

[Einion Yrth]

MartG said:

Eric Mc said:

I wonder why this issue took so long to manifest itself? Was there something a bit different about the conditions surrounding the helium tank pressurisation on the day of the explosion?

Or just chance that THIS time the tank failed, whereas previously if the fault occurred it didn't cause the tank to rupture

They've not been doing the sub-cooling trick for long, potential failure modes discussed on NASA Space Flight fora would suggest that may be a pertinent factor.
Solid oxygen, with carbon and high pressure have a regrettable tendency to go "BANG!".

[Eric Mc]

That sounds plausible. As I did think that up to now, fuelling did not seem to be a problem. It's when procedures change that unexpected events sometimes occur.

[MartG]

Another article

http://spaceflightnow.com/2016/10/31/spacex-hopes-...

[Eric Mc]

Concerns raised over fuelling procedures for manned Dragon flights. It does sound rather dodgy to me, especially after the recent "anomaly" -

http://www.space.com/34670-spacex-rocket-fueling-p...

[MartG]

Eric Mc said:

Concerns raised over fuelling procedures for manned Dragon flights. It does sound rather dodgy to me, especially after the recent "anomaly" -

http://www.space.com/34670-spacex-rocket-fueling-p...

Just a new way of doing things, and now they've found what the issue was they can address it

Wile Stafford is right to raise his concerns, hopefully his 'but we've always done it this way' sentiment will not stop private innovation. It's not like SpaceX plan to strap 'uncontrollable once lit' SRBs to their manned rocket, unlike NASA

[Buzz84]

Eric Mc said:

Concerns raised over fuelling procedures for manned Dragon flights. It does sound rather dodgy to me, especially after the recent "anomaly" -

http://www.space.com/34670-spacex-rocket-fueling-p...

Surely that's why there is a capsule "eject" function, to trigger and propel the capsule to safety if anything were to happen to the booster.

https://youtu.be/1_FXVjf46T8

[Eric Mc]

You hope. Even though the Russians did use the emergency escape system when a rocket caught fire on the pad, nobody has ever had to use this type of system because of a rocket explosion on the pad. I can see where Stafford is coming from. Having people in the vicinity of a rocket whilst the refueling is underway is an additional risk.

Are SpaceX actually saying that they need the extra fuel they can squeeze in by using this method of fueling to make the manned flights work? In other words, the Falcon can't lift a maned payload without this form of refueling?

[MartG]

Eric Mc said:

Are SpaceX actually saying that they need the extra fuel they can squeeze in by using this method of fueling to make the manned flights work? In other words, the Falcon can't lift a maned payload without this form of refueling?

It probably depends on the destination orbit.

Maybe it would be simpler to just add a few feet to the length of each tank instead

[Eric Mc]

I think it's fine for unmanned missions - as the weight and altitude of payloads can vary from flight to flight.

I would have guessed that manned flights would be pretty consistent weight wise and I understood that, at least for the first few years, all manned missions were to the ISS. I assumed a standard fuelled Falcon could hoist a crewed Dragon to the ISS without any "extra" trickery to get more fuel into the rocket.

[p1stonhead]

[Eric Mc]

Hope that goes well.

[scubadude]

p1stonhead said:

I was amused on FB and Twitter how many commentators where impressed by the size of the ITS O2 tank with many comments about how they hadn't realise how big it was, no one has ever built a tank that big etc... all crap of course... especially as that is the smallest tank (by some margin) in the BFR/ITS stack.

Am fairly sure some people can't envisage just how "big" SpaceX are going on this one! We could argue the merits of their design philosophy all day but you can't fault their "Go Big or Go Home" aspirations :-)

[RobDickinson]

Isn't it the biggest composite tank made?

[annodomini2]

They're aiming for 500 t to LEO so it will be the biggest lifter built if they finish it.

[Einion Yrth]

RobDickinson said:

Isn't it the biggest composite tank made?

I believe so, but they'll have to build bigger to make BFR work.

[RobDickinson]

If they get the go ahead SpaceX will be attempting to launch a falcon 9 on 16th December with some Iridium NEXT satellites.

They also have an ISS resupply mission in January afik which I am sure they will want to get up considering the failure of the recent Progress launch

[Eric Mc]

Just shows that with rockets, even the old reliable aren't all that reliable.

[MartG]

Link to a large cutaway pic of the Falcon Heavy https://logiclogiclogic.files.wordpress.com/2015/1...

[Eric Mc]

Looks a beast.