Hacker News Reader

Comment by rileyphone | Hacker News Reader

At least this issue seems to be with the lander and not the rocket, which had never launched before. Almost twenty years since the creation of ULA to the point of launching their own design means it would have been a heck of a letdown to see it fail.

Aside that, it was cool to see two launches at the Cape yesterday less than 9 hours apart. Recommend to anyone who gets the opportunity to go out there and see one at some point (though the chances that any given launch gets scrubbed is never low).

View on HN

Fun fact (for me, anyway): I live 35 miles from the launch complex, and the ground-shaking launch of the Vulcan Centaur rocket woke me up at 2:19 this morning.

I can't imagine how intense it was for people much nearer to Cape Canaveral.

That is one hell of a rocket!

Once Starship is up and running, I am really curious how the noise will affect the surrounding areas. For example, the HLS version of Starship, for Artemis III, will require something like 16 Starship launches in short order.

I am a huge SpaceX fan, but if SpaceX's vision of many Starship launches per day becomes reality, then that will certainly be interesting for anyone within 50 miles of the pad.

Are launches permitted when prevailing winds would send liftoff exhaust over populated areas ?

Up to this point, that's not been a factor considered by anyone in a position of authority.

Starship uses Methane-Oxygen, which burns way cleaner than Kerosene-Oxygen, which is used by Falcon 9.

The thing people should be concerned about are solid rocket boosters, which SpaceX does not use. Solid boosters have polluted every "untouched" alpine lake on the planet. Those have been used by the new Vulcan, Space Shuttle, and a lot of other rockets.

Tim Dodd has an excellent video and write-up on this topic:

https://everydayastronaut.com/rocket-pollution/

provided it burns yes.

any accident that results in the releasing of that amount of methane unburnt would be horribly damaging.

luckily, rockets rarely DONT go bang and burn when things go wrong.

Like a lot of cow burps right?

Basically the equivalent of a herd of 7500 cows burping away for a year.

Bad but I'm not sure that 750ton of methane is horribly damaging compared to a billion cows

but its not compared is it.. its in ADDITION to.

The exhaust from Starship is just CO₂ and water (CO₂ causes climate change, but that's not a local effect.)

Vulcan is dirtier because of the solid rocket boosters.

I'm not sure about Raptors specifically, but usually liquid rocket engines run rich (or, as Russians say, "sweet", rather than "sour", or lean), which means that there's excess of methane in the exhaust. Methane is a powerful (comparing to CO2) greenhouse effect agent, which fortunately doesn't have as long atmospheric life as CO2.

This is a closed cycle, so I would expect it to be cleaner, but I don't know for sure.

Raptor (Starship) is closed cycle, and BE-4 (Vulcan) is oxygen rich, so neither should be dumping unburned methane during normal operation.

BE-4 has oxygen rich pre-burners, while Raptor is full-flow. However both engines use a fuel rich mix in the main combustion chamber.

But the pollution from either is far less than from a solid fuel engine.

Interesting. Then I wonder how the GHG emissions of methalox/kerolox engines actually compare? Methalox emits less CO2, but unburned methane is 30X worse than CO2.

At least some of the unburnt gas in the exhaust plume will ‘afterburn’ when it mixes with oxygen in the atmosphere.

Aside from CO2, methalox engines produce noticeably less soot than kerolox.

Indeed. Although Texas is not a primary launch site long term. It’s a development site. The Cape is going to be a primary, with multiple Starship-capable pads.

Yes, but even the Cape has lots of people living within sound range. I am not trying to stir the pot, it depends on the wind, etc. But, if we will see hundreds or even thousands of Starship launches per year, it's hard not imagine a system of methane and oxygen pipelines running out to offshore platforms being required.

Ideally, those platforms would be located somewhere without much sea life. Though that's utter speculation, because I have no idea how well air pressure shock waves transfer to under the sea.

I think at thaT point they could probably afford to just build an offshore launch complex, or build out in the middle of nowhere Arizona or something.

... well... unless it was some issue with the rocket's delivery that impacted the lander, like damaging a portion of it on release, or shocks on takeoff?

They should have the measurements to know if the rocket had any forces that went out of spec during launch

essentially, Apollo 13

Apollo 13's emergency was caused by the spacecraft's service module, not Saturn V:

https://en.wikipedia.org/wiki/Apollo_13#Investigation_and_re...

Apollo 13 (and previous flights) did experience "pogo oscillation" from the Saturn vehicle which caused one of the first stage engines to shut down early.

https://en.m.wikipedia.org/wiki/Pogo_oscillation

The damage to the Apollo 13 service module that caused oxygen tank 2 to rupture almost certainly happened well before launch during ground testing.

See https://nssdc.gsfc.nasa.gov/planetary/lunar/ap13acc.html

So? It was irrelevant to the issue. The issue was traced back to manufacturing.

Reply on news.ycombinator.com