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1 hour ago, FloatingFatMan said:

1 or two rockets every few months won't make a big difference... But Musk wants a fleet of these things and THAT is where it becomes an issue.  They should re-evaluate the fuel mix NOW rather than wait for an inevitable future ban.

Methane is usually burned off, whatever is vented back into the atmosphere will be minor even with an entire fleet of rockets.

 

The methane fight has many other places to start than rocketry.

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4 hours ago, FloatingFatMan said:

Let it not be said that I'm unwilling to admit where I'm wrong, and even though I still have many doubts about Starships' viability, I'm not ashamed to congratulate them on their successes, so well done SpaceX on a successful flight and landing of SN15!

 

However, I wonder if this article below will prove to be a roadblock to them moving forwards?

 

https://www.bbc.co.uk/news/science-environment-56933443

 

 

Musk sort of talked about this on the Joe Rogan show a while back.  Rogan wanted to know if there was a way getting to space using electric instead of a fossil fuel because they were talking about Tesla also.  Musk's goal was to get rid of fossil fuels everywhere, except when getting into orbit.  They didn't really discuss methane though so it isn't a full answer to your concern... his goal is to offset it.  He also mentioned that he's for a Carbon tax even though SpaceX would be paying a lot if I remember correctly.

 

Also, is there another fuel you can make easily on Mars?

The problem with methane is when it gets into the atmosphere, like when cows fart, rather than rockets burn it, turning it into water and carbon dioxide.

Like plastic, the real problem is not the use of but improper disposal of the stuff, as long a it is handled with a little thought,  the harm is minimal.

7 hours ago, FloatingFatMan said:

1 or two rockets every few months won't make a big difference... But Musk wants a fleet of these things and THAT is where it becomes an issue.  They should re-evaluate the fuel mix NOW rather than wait for an inevitable future ban.

 

SpaceX, ULA, Blue Origin, Arianespace, Russia, most all the majors, are moving to methane.This is being done because it's cleaner burning, efficient, and delivers a pretty good punch. 

 

Mechane is a C1 simple hydrocarbon, 1 carbon atom per molecule. Combustion product: CO2 and water.

 

RP-1 (rocket grade kerosene) is a C10 - C16 complex hydrocarbon which produces a chemical factory's worth of pollutants.

 

Solid rocket fuels, like the Shuttle, Ariane, Indian & SLS  boosters , also produce noxious compounds along with hydrochloric acid vapors and unburned chlorates.

 

Many Chinese rockets burn toxic hypergolics like nitrogen tetroxide and monomethyl hydrazine. 

 

Yuk.

 

Starship,

 

During pre-launch activities there is little to no methane release; methane tank vapors are collected and sent back to the tank farm where a recondenser re-liquifies it for later use. 

 

Their use of methane extracted from natural gas is a temporary practice.

 

As it is now, SpaceX is buying methane from a local supplier but they've acquired a natural gas well near the build site. They will be purifying to methane and liquifying it for launches at the well site.  Also going in near the well site is an oxygen condenser for making their own liquid oxygen.

 

Future methane for Starship launches will be "green," made from CO2 extracted from the atmosphere.  A good thing, yes?  This tech would serve double duty; producing launch fuel on Earth, and producing  return fuel on Mars (which has a CO2 atmosphere) or wherever.


SpaceX's baseline CO2 --> CH4 chemistry is the well known Sabatier reaction, invented in 1897.  On Earth it'd be powered by wind and solar. 

 

The Musk Foundation is also funding a $100 million Carbon Removal X-Prize to evaluate other carbon capture processes, which could also be used to make methane.

 

https://www.xprize.org/prizes/elonmusk

 

Quote

XPRIZE Carbon Removal is aimed at tackling the biggest threat facing humanity - fighting climate change and rebalancing Earth’s carbon cycle. Funded by Elon Musk and the Musk Foundation, this $100M competition is the largest incentive prize in history, an extraordinary milestone.‎

 

Edited by DocM
4 hours ago, Skiver said:

Is that it back on one of the launch pads? It's certainly not supported by a crane

 

image.png.30c0e0657887a3bc934df96b82024e70.png

I believe that's where it landed. The launch pad it took off from is near that (taller) crane thingy...if my orientation is correct.

On 07/05/2021 at 14:15, warwagon said:

I was thinking that exact thing. Turn around and lets fly this puppy again.

I think it has to present an actual learning opportunity for them to warrant the risk. There's little point to them launching this and it blowing up 30 seconds into the mission, I think it needs to stand a reasonable chance of sticking the landing for them to really learn anything from using it again.

I think the main issue is the downtime for the site. When they do flights and static fires the whole site is shutdown, stopping work on other projects (SN16-20,BN3,Launch Tower, ground support, etc).

If the re-flight has a large learning opportunity then they will do it, but if it is going to shutdown the site too much, then they will move on.

 

However if reflying it is the same as flying SN16-19, then it would make sense to re fly than build a new one then fly it.

 

If they stick SN16 I would suggest they may scrap 17-19 and move to orbital prototypes(20+) and re fly 15 and 16  to test landing options until they blow.

9 hours ago, IsItPluggedIn said:

I think the main issue is the downtime for the site. When they do flights and static fires the whole site is shutdown, stopping work on other projects (SN16-20,BN3,Launch Tower, ground support, etc).

If the re-flight has a large learning opportunity then they will do it, but if it is going to shutdown the site too much, then they will move on.

 

However if reflying it is the same as flying SN16-19, then it would make sense to re fly than build a new one then fly it.

 

If they stick SN16 I would suggest they may scrap 17-19 and move to orbital prototypes(20+) and re fly 15 and 16  to test landing options until they blow.

Looking at Brendan Lewis build progress sheet then there is no 18 and 19 even in production so it looks like they're already skipping those. 

 

16 is almost done so it makes sense to carry on with that one and I suspect they're far enough through 17 to warrant that one going too.

 

20 I believe Elon was hoping to be doing the orbital flights with so that's a completely different so shouldn't really be considered as part of the this phase. 

 

Looking at it, I'm not even sure they have time to re-fly 15 as it takes 1-2 weeks minimum to get starship down to the pad, cryo tested, raptors installed, static fire and then launched. I guess it will depend on how close BN3 and the launch tower is by July.

13 hours ago, Skiver said:

>

Looking at it, I'm not even sure they have time to re-fly 15 as it takes 1-2 weeks minimum to get starship down to the pad, cryo tested, raptors installed, static fire and then launched. I guess it will depend on how close BN3 and the launch tower is by July.

 

They built a new jig for the crawlers so they can pick up landed vehicles, and it's moving SN-16 to Sub-orbital Pad B today

 

It does look like at least 18 & 19 are being scrapped, and 20 is the intended orbital vehicle. 

Starship reaction control system thruster test.

 

When first discussed these were specced at about 10 tonnes of thrust, about 22,046 lbf. 

 

Besides being used for reaction control, there are ~24 thrusters around the circumference of Starship HLS for lunar landings. Mounted high up, just below the cargo / airlock deck and angled down, the plumes from this array wouldn't kick up near as much debris as firing the main Raptor engines. This minimizes the possibility of damage to Starship HLS and surrounding infrastructure.

 

Locals say thought these are small engines they're extremely loud.

 

(play all the way through)

 

Starship HLS with landing thrusters labeled

 

1488125950_StarshipHLScrop-labeled.thumb.jpg.e6b14e2348e6e574c0af2d76fb044b7c.jpg

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