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1 hour ago, RCgothic said:

Flare stack's days are numbered:

 

It will still be there for emergency or if you got lots of gas over short period of time but it will not burn all the time. 
They will need an igniter up there, perhaps the same as on the raptor engine?

On an oil platform I helped design they actually fire an small rocket up an pipe to the top of the tower, the rocket ignites the gas, then its burned out if fall down into an bucket. Its an sort of revolver magazine for the rockets so you can trigger an new one if the first fail. 
Blew my mind, I assume its done to keep the top of the tower as simple as possible, have fun trying to get up there during bad weather fixing an broken igniter. 

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19 hours ago, RCgothic said:

So Starship could probably send two D9 Caterpillar Bulldozers to the moon in one go from a payload perspective. Got to move a lot of earth to build a moonbase!

But would you necessarily want to go solar-electric for power? Earth movers require a lot. Could you modify an internal combustion engine to run on fuel/oxidiser? Superchargers would be super-effective sucking down to vacuum. Or would a fuel/oxidiser turbine work better with exhaust to vacuum?

Without an oxygen environment, heavy earthmoving will require tethered power, we already do this for mining.

 

The only alternative is onboard nuclear power, which I would love to see happen

18 hours ago, RCgothic said:

your bulldozer weighs less and therefore has less traction.

Yeah, expect much wider and longer tracks on lunar optimized equipment, very similar to how we already optimize such equipment for swampy terrain

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Speaking of droneships, I wonder if an ASDS large enough to accommodate Super Heavy will ever be necessary. They might need it for the first few landings, because it lands very close to the launch pad and they don't want a landing failure damaging the pad while they're still getting the hang of flying SS/SH.

Edited by RealKerbal3x
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1 minute ago, RealKerbal3x said:

Speaking of droneships, I wonder if an ASDS large enough to accommodate Super Heavy will ever be necessary. They might need it for the first few landings, because it lands very close to the launch pad and they don't want an early landing failure damaging the pad.

Why not just build a second landing pad a safe distance away and use that one (with a crawler or crane to move it over) until they get it reliable?

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6 minutes ago, sevenperforce said:

Why not just build a second landing pad a safe distance away and use that one (with a crawler or crane to move it over) until they get it reliable?

That didn't occur to me, and is probably a better idea :P

It seems like they're mainly gearing Super Heavy towards RTLS landings, since with orbital refuelling there's no need for Starship on its own to have the capability to get significant payload beyond LEO. However, ASDS landings for Super Heavy could allow slightly more payload to GTO, for example, without the need for a tanker launch.

Edited by RealKerbal3x
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It'd certainly be less expensive to lithobrake on a concrete pad than a drone ship. I think JRTI 1 was written off by CRS-6's hard landing.

 

On a related note, the ASDS page on Wikipedia needs a knowledgeable person to go through and edit it. JRTI 2 is still assigned West coast, when it's now Atlantic.

The history section also needs sorting. It talks about JRTI 1 and how it is retired, before the plans for ASOG. Then it talks about JRTI 2 and ICISLY being the active fleet. Then it talks about ASOG again.

The bit about JRTI 2 being constructed partially from parts of JRTI 1 and therefore confusingly calling it both the first and third barge needs to die in a fire.

 

Needs a good editer, basically.

Edited by RCgothic
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Just now, RealKerbal3x said:

That didn't occur to me, and is probably a better idea :P

It seems like they're mainly gearing Super Heavy towards RTLS landings, since with orbital refuelling there's no need for Starship on its own to have the capability to get significant payload beyond LEO. However, ASDS landings for Super Heavy could allow slightly more payload to GTO, for example, without the need for a tanker launch.

I think it depends in part on whether SpaceX is able to pull off its plan for higher-powered unthrottleable fixed-gimbal SL Raptors. If they can manage those, then that will really give Superheavy a ridiculous amount of thrust off the pad and a lower dry mass. Better TWR means cheaper RTLS.

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22 hours ago, RCgothic said:

The rock weighs less, but if it's firmly anchored you need to shear through it. Same energy to do that anywhere in the solar system.

A solar farm with a load of multi-purpose swap-in battery packs for an electric vehicle is probably most efficient.

Still, a Kerolox supercharged diesel engine would be cool.

It will depend on what type of regolith you are working with. 

If you are simply scooping loose, lightly compacted dust and granular particles, the lack of gravity compared to equipment strength will be in your favor.

However if you are trying to break lava rock, large boulders or very compacted soil you will have reduced traction because your reduced weight (friction*Normal force). I don't know exactly how compaction relates to gravity on the moon.

A swarm of autonomous mini-soil scoopers could be more efficient that a massive powerhungry earthmover.

If the dozers are autonomous they don't even have to work very fast so working slower is ok. The 

 

1 hour ago, RCgothic said:

The bit about JRTI 2 being constructed partially from parts of JRTI 1 and therefore confusingly calling it both the first and third barge needs to die in a fire.

This is an old problem.

https://en.wikipedia.org/wiki/Ship_of_Theseus

 

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By the way, I know we all applied Tory Bruno's cost formula to SLS the other day. Booster engines are 1/3 of rocket hardware.

Appliedto SSSH 31 engines at ~$1m each comes to ~$90m to build, ~$180m all inclusive.

Elon says fuel is ~1000th of flight cost. So ~$180k to fuel.

Seems consistent with what I've heard previously.

Edited by RCgothic
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On 5/6/2020 at 7:40 PM, mikegarrison said:

I didn't want to say that, but yeah.

And we were both wrong...

She came home a few minutes ago.

Feel like there should be some "ObSpaceX" content here, but I've got nothin'.

Spoiler

0Gfi9pt.jpg

 

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10 minutes ago, Flavio hc16 said:

SN4 is engineless, will they go for desttructive test tonight?

I doubt they'll test SN4 to destruction deliberately, otherwise SN5 would have to do all the testing that SN4's already done again. They're probably removing the Raptor temporarily to do non-engine-related testing on SN4 before it does its hop test.

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Maybe having done the engine tests the wanted to get done and with SN5 close behind they're going to see if they can increase the proof pressure. Last time they acheive the minimum for engine operation, but human flight needs more like 8bar.

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