Technology, Science and the Environment.

[ozleicester]

7 minutes ago, leicsmac said:

and out in space.

That serves no purpose for life on earth, bar our greed for more of everything.

[leicsmac]

Just now, ozleicester said:

That serves no purpose for life on earth, bar our greed for more of everything.

As per above, the asteroid coming through the atmosphere a half-second from impact (or the gamma-ray burst from a nearby supernova) would indicate differently.

 

Yes, long shots, but over time inevitable and something that must be prepared for. To say nothing of the fact that regardless of what we do (bar the most extensive terraforming) the Earth won't remain habitable forever.

[Smudge]

6 minutes ago, ozleicester said:

That serves no purpose for life on earth, bar our greed for more of everything.

Exploration has always found new options.

[The Bear]

6 hours ago, ozleicester said:

That serves no purpose for life on earth, bar our greed for more of everything.

Completely wrong. There are a multitude of benefits and inventions that we now have down here on Earth thanks to space travel and research into space exploration. 

 

Same with particle physics and almost all pure experimental scientific research. 

[SpacedX]

[ozleicester]

37 minutes ago, The Bear said:

Completely wrong. There are a multitude of benefits and inventions that we now have down here on Earth thanks to space travel and research into space exploration. 

 

Same with particle physics and almost all pure experimental scientific research. 

tbf if the same amount of $$$ were invested into research, those same benefits and inventions and more may have been discovered.

[SpacedX]

17 minutes ago, ozleicester said:

tbf if the same amount of $$$ were invested into research, those same benefits and inventions and more may have been discovered.

Why are you asking the same questions that were answered two pages ago on this thread? You even thanked @leicsmac for his excellent reply. 

[ozleicester]

Just now, Line-X said:

Why are you asking the same questions that were answered two pages ago on this thread? You even thanked @leicsmac for his excellent reply. 

because i still feel it is a waste, its still dick swinging and war development and a waste...as i watched Millions of people in Pakistan become homeless the next story was billions of $ being spent on unnecessary space war mongering and bragging rights.

[The Bear]

46 minutes ago, ozleicester said:

tbf if the same amount of $$$ were invested into research, those same benefits and inventions and more may have been discovered.

Well no, because we invented stuff we didn't know we needed at the time. And it was something extremely specific that wouldn't have been in any area of general research. 

[leicsmac]

52 minutes ago, ozleicester said:

because i still feel it is a waste, its still dick swinging and war development and a waste...as i watched Millions of people in Pakistan become homeless the next story was billions of $ being spent on unnecessary space war mongering and bragging rights.

I'm sorry, but beyond anything else, if we don't go into space, humanity becomes extinct in much shorter order than otherwise. That is a fact and a probability so extreme as to be pretty much an inevitability.

 

I cannot comprehend how someone beyond an ardent nihilist would think space exploration to be a waste knowing that to be true, and Idon't think you're a nihilist.

[st albans fox]

Money rarely disappears except in corruption where it ends up in ‘Swiss bank accounts’ ….

 

the idea that doing x or y is a waste is misplaced 

 

you can argue that it would be better spent in other areas but then you run into debates on how effective that spend is in those areas ….

[leicsmac]

H2 leak - delay?

[SpacedX]

11 minutes ago, leicsmac said:

H2 leak - delay?

That was resolved.

 

The current hold is unusual. Normally T-10. The issue is whether they can come up with a work around on the engine chill down. Two hour launch window - but if they can't resolve it today, will go on Friday. Launch window opens at 16.48 UTC again two hours long.

[leicsmac]

14 minutes ago, Line-X said:

That was resolved.

 

The current hold is unusual. Normally T-10. The issue is whether they can come up with a work around on the engine chill down. Two hour launch window - but if they can't resolve it today, will go on Friday. Launch window opens at 16.48 UTC again two hours long.

Got it, still at work so difficult to get live updates.

[SpacedX]

Just now, leicsmac said:

Got it, still at work so difficult to get live updates.

It was a service mast leak.

 

The issue now appears to be balancing engine 3 and then complete the chilldown/bleed in time to make the launch window. Holding for twenty minutes so far at T-40 is not a great sign for a launch today.  

[SpacedX]

There is no consistent bleed flow. It was discovered at hot fire tests at Stennis that closing the vent at the top of the tank can establish this evenly through all four engines.On the pad at Kennedy, the rocket is in a different configuration, but engineers couldn't look at this in June during the WDR due another leak.

 

It takes time to condition the engines, which they haven't yet done. If they can't resolve it and troubleshoot it pretty much immediately, there won't be sufficient time to do this within the launch window today. 

Edited 29 August 2022 by Line-X

[Zear0]

2 hours ago, ozleicester said:

because i still feel it is a waste, its still dick swinging and war development and a waste...as i watched Millions of people in Pakistan become homeless the next story was billions of $ being spent on unnecessary space war mongering and bragging rights.

Kind of in the middle ground on this one. Completely on the side of space exploration as it's essential for civilisation, but this one is a bit weird. SLS is scrounged parts from the shuttle and what was left over from Constellation before the US deemed it a waste of time. This specific programme exists purely for the benefit of jobs in specific congressional districts.

 

I'll be watching with excitement, as it's still awe inspiring kit, but hard to get too dewey eyed over this programme. I suspect it'll be binned before we get to Mars; that will surely be Starship or a derivative. SLS doesn't seem, from my understanding, to have introduced any significant new technologies and just looks so out of place in an era of reusable rockets. Even the shuttle had reusable fuel tanks. 

 

Still, looking forward to it! 

[leicsmac]

8 minutes ago, Zear0 said:

Kind of in the middle ground on this one. Completely on the side of space exploration as it's essential for civilisation, but this one is a bit weird. SLS is scrounged parts from the shuttle and what was left over from Constellation before the US deemed it a waste of time. This specific programme exists purely for the benefit of jobs in specific congressional districts.

 

I'll be watching with excitement, as it's still awe inspiring kit, but hard to get too dewey eyed over this programme. I suspect it'll be binned before we get to Mars; that will surely be Starship or a derivative. SLS doesn't seem, from my understanding, to have introduced any significant new technologies and just looks so out of place in an era of reusable rockets. Even the shuttle had reusable fuel tanks. 

 

Still, looking forward to it! 

Those are fair criticisms tbh. The SLS in terms of the basic rocket tech is something NASA might have come up with 40 years ago. In fact,  it *should* have come up with it then.

 

However, I'm just happy that there is *any* solution that's getting humanity back into space because it's essential, the clock is ticking and through public apathy and geopolitical bullshit we've wasted far too much valuable time already.

[SpacedX]

8 minutes ago, Zear0 said:

Kind of in the middle ground on this one. Completely on the side of space exploration as it's essential for civilisation, but this one is a bit weird. SLS is scrounged parts from the shuttle and what was left over from Constellation before the US deemed it a waste of time. This specific programme exists purely for the benefit of jobs in specific congressional districts.

 

I'll be watching with excitement, as it's still awe inspiring kit, but hard to get too dewey eyed over this programme. I suspect it'll be binned before we get to Mars; that will surely be Starship or a derivative. SLS doesn't seem, from my understanding, to have introduced any significant new technologies and just looks so out of place in an era of reusable rockets. Even the shuttle had reusable fuel tanks. 

 

Still, looking forward to it! 

Booster reusability is desirable, but has drawbacks. First, if you don't have a fast enough launch cadence, you can spend more on recovery than you save by reusing the booster. Second, you take a payload hit for the recovery system on the booster. The Falcon 9 B5 can lift up to 22.8 tons to LEO when expended, but only up to 16.3 tons when landed on a drone ship (B1051.12). Doing a Return to Launch Site (RTLS) landings, costs even more payload. The SRBs that were recovered during the Shuttle era were stripped down to bare metal and basically rebuilt every flight. So with SLS launching once or twice a year, the cadence doesn't really justify recovering the booster. Not to mention that it gets higher and faster than a Falcon 9. The SLS Block 1 can get Orion to the Moon, but not with the kind of payload hit like F9 has. The SLS Block 1B will send along a Lunar Gateway module with Orion, so it really can't take the payload hit either. SLS started design work in 2011, four years before SpaceX landed the first booster and almost 6 years before they reused a booster. 

 

The RS-25 engines are of course formerly the SMEs on the shuttle - all of which have flown. The Service module uses an AJ-10 engine which was used in Shuttle Orbiter Orbital Maneuvering System pods - the one used for Artemis 1 belonged to Atlantis. The reaction control systems are derived from the Apollo R-4D hypergolic system. Interestingly, each shuttle engine contains a component from each of the shuttle fleet including STS-1.  

 

Looking like a scrub today. 

[Zear0]

4 minutes ago, leicsmac said:

Those are fair criticisms tbh. The SLS in terms of the basic rocket tech is something NASA might have come up with 40 years ago. In fact,  it *should* have come up with it then.

 

However, I'm just happy that there is *any* solution that's getting humanity back into space because it's essential, the clock is ticking and through public apathy and geopolitical bullshit we've wasted far too much valuable time already.

Hopefully the super heavy launch tech that NASA still dominate can be shared with the reusable rocket partners so everyone is a winner for whatever comes next.

 

Was a bit of a negative perspective on my part as when I got the tour of the facility the other year and saw this very launch pad, today seemed forever away. Goosebumps being there at that time. 

[SpacedX]

Launch officially scrubbed. 

[leicsmac]

Shit.

 

Guess we go again in a few days.

[SpacedX]

3 minutes ago, leicsmac said:

Shit.

 

Guess we go again in a few days.

Yeah Friday. I think the launch window opens this Friday at 12.48 EST. 

 

Hopefully this will afford sufficient time to develop a process to resolve the chilldown issue on Engine 3. This is the first time run this engine bleed procedure has ben performed with the current ground launch configuration at Kennedy. They weren't able to do it during the WDR in June due to a leak issue. As I understand it, a propulsion system running on cryogenic fuel has to pass a chill down phase before ignition. Because of the turbo pumps in the propulsion system, this is essential since they have to deliver the extremely cold fluids. The feed lines, turbo pumps, valves and ducts of the engine have to be equalised with the extremely cold temperature of the hydrogen and LOX. During the hot run the turbo pump delivers the fluid at a ridiculously high rotational speed. The turbopumps on the Saturn V each produced 56,000bhp. Starting the pump without the prior chill down would cause cavitation, the bearings would not have sufficient cooling, and the fuel or oxidiser would be pumped into the chamber with a dangerously high fraction of bubbles and gas. Today, they couldn't achieve the required purge temperature on engine 3. During testing at Stennis, they encountered the same issue with two engines, but found that closing the vent cap on the core stage forced the chilldown. I gather today, engineers attempted something similar on the problematic engine by isolating the other three. 

 

It may even be that there is not a satisfactory solution by Friday - in which case there are further launch windows in September. 

 

 

[leicsmac]

Official word is the next launch window for Artemis I is Saturday at 2.17 pm EST (7.17 pm UK time).

 

Going to be a very early start/late night on this side of the world.

[SpacedX]

10 hours ago, leicsmac said:

Official word is the next launch window for Artemis I is Saturday at 2.17 pm EST (7.17 pm UK time).

 

Going to be a very early start/late night on this side of the world.

I do hope it goes as early in the window as possible for you. 

 

There's a possibility that a faulty sensor caused the erroneous readings on Monday - if so that would mean rollback into the VAB. They intend to initiate the chilldown procedure half an hour earlier on Saturday once fuelling has commenced.