Here’s how orbital dynamics wizardry helped save NASA’s next Mars mission
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Launch window opens in about 10 minutes as I write this, and the livestream certainly seems to be "we're planning on launching today" (currently at T-40 minutes).
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That article is from January.
The countdown is holding at the moment, waiting for the weather to clear.
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No, still on a weather hold.
Edit: Weather is supposedly clearing, there’s an unspecified GSE issue being worked, and the clock is now ticking down at L-26 minutes.
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Go, conditional on weather and apparently a wayward ship or boat. L-14 minutes.
Edit: Holding at 4:33, waiting on final approval from weather.
Edit: Holding at 4:33, waiting on final approval from weather.
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That orbit is nice but... can it land in the Sun Station?
Jokes aside, that's some cool planning. Is that a bit of a slingshot out of Earth, too?
Jokes aside, that's some cool planning. Is that a bit of a slingshot out of Earth, too?
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I love that when they missed the window for a "proper" Mars trajectory, they just found a new crazy one that still works. Rich Purnell is a steely-eyed missile man!
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Well, a new one that "works." It's not as nice as not spending an extra year being exposed to radiation, etc., but it gets it there ... essentially when it would arrive if ULA launched it during the next window. All that's saved is storage costs.
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On the BO feed, there is (was) fire right next to the rocket. Is that caused by boiloff from the ground infrastructure?
Was the fire intentional?
I don't recall seeing that for other scrubbed launches.
Was the fire intentional?
I don't recall seeing that for other scrubbed launches.
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It's a flare stack. As the methane on board warms up, some of it has to be released from the tank. You can’t just vent it overboard, so instead it is tapped off to a remote location and burned off there.
You'll also see it in SLS launches, they need to flare off hydrogen.
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Is someone forcing you to read articles that you don't like to read? If the answer is no, then bye.
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OK, thanks. I was assuming boiloff, but I thought the rockets just vented it go the outside.
So basically the same concept that oil rigs use, where they burn gases that come up along with the oil from below.
IIRC, it's both safer and more environmentally friendly to burn it rather than just dumping it.
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The Earth has much more mass than the moon. When using gravitational assists, more mass for the booster body is better.
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I am curious to learn though:
What is the typical % of the fuel being able to be recycled for another launch?
I presume modern launches pump it back through the umbilical (relatively slow and carefully) back to the actively chilled tank farm, and tanks safely purged with inert gas, but what % of fuel is saved?
Are the numbers similar to 5% flare and 95% recycle? Or a much worse loss?
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I’m confused as to exactly what the difference is between methane and natural gas.
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So the latest seems to be T -2 hrs if I got it right at the best? It's nearly midnight in UTC here, to I am calling the watch off. See you tomorrow.
ETA: Seems my timelines might have gotten mixed up by watching the various feeds at different times, but the latest seems to be a scrub?
Fuck, I could have gone to sleep earlier ;-)
ETA: Seems my timelines might have gotten mixed up by watching the various feeds at different times, but the latest seems to be a scrub?
Fuck, I could have gone to sleep earlier ;-)
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"Natural gas" can have all sorts of bad things in it like sulfurs, etc. Processed natural gas (like you'd find in a pipeline) gets rid of most of that, but can still have 5% of something other than methane.
Importantly, New Glenn is flying on liquefied natural gas - not just natural gas. LNG can have a few percent of ethane, but not really anything else.
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Methane would be just methane. Natural gas is mostly methane, but with other stuff. But it's more the restrictions on what it can have that matters, than that it has more than just methane. At least usually, for ground purposes. For it's use as rocket fuel, the relevance of the issues mentioned in the link may vary.
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AIUI natural gas is a combination of multiple alkanes. Methane is a specific compound (actual molecular makeup) of the alkanes that can be extracted from the natural gas soup. As others note, it's the gaseous equvalent to sweet crude, but mostly made of methane plus extras that are not wanted.
And what @Wickwick says below
EDIT: ethanes -> alkanes
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The word you're looking for is "alkanes" not "ethanes." The latter is a specific alkane with 2 carbons (and 6 hydrogens).
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But keep in mind the original post was claiming it was an important distinction that it was natural gas and not methane. Are they saying New Glenn needs that extra ethane? Or are we just being exact for the sake of exactness (not necessarily a bad thing)?
EDIT: Or maybe that it makes New Glenn cheaper to launch that it doesn’t need pure methane?
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With the scrub, any bets on whether will BO try for an exemption to the daylight no-rocket-launch rule that starts tomorrow?
IMHO, if I were an engineer/manager for an orbital-class booster attempting to make its first landing on a dot of a barge in the open ocean, I’d want to see it, and/or use visual clues to validate the performance. I know the booster doesn’t care (or shouldn’t).
If not approved for a waiver, launch at 0530ish so much of the separation, boost back, etc are in daylight?
Just curious.
IMHO, if I were an engineer/manager for an orbital-class booster attempting to make its first landing on a dot of a barge in the open ocean, I’d want to see it, and/or use visual clues to validate the performance. I know the booster doesn’t care (or shouldn’t).
If not approved for a waiver, launch at 0530ish so much of the separation, boost back, etc are in daylight?
Just curious.
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Not needing pure methane is an engineering challenge overcome. That small fraction of ethane can cause a bit of firing issues (the heating value is slightly different), but their controller must be good enough.
And yes, LNG is way cheaper than cryo methane (the latter being separated from the former on-site).
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Uh as someone who lives in Boston, a city that loves its rotaries, I can tell you that doesn't work like that. Drive Leverett Circle in Boston at 5pm and see how queuing going around a center point does in heavy traffic. To quote that great astrophysicist Chevy Chase "And here's Big Ben!..."
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Let me suggest the lanes for the orbital roundabouts are a weee bit larger than the traffic circles in Boston...
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And make it harder to kill it off if it's in space already, although that seems to be a thing too.
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jonbob_newcastle
Ars Praetorian
Practically speaking there isn't one. What comes out of my gas main may have been purified* but in engineer speak it's still called "natural gas", as opposed to town gas**, propane, butane or what have you.
I suspect the writer used "natural gas" as a synonym for methane. It's not uncommon. It's certainly what I would do if the point I was trying to emphasise is that the fuel isn't something that's expensive to manufacture/complicated to store/so toxic it's embarrassing.
* Then slightly adulterated with a very smelly impurity.
** Which no-one really uses these days, but the names date back to when they did.
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The ratio is roughly the difference between the size of the flare and the size of the rocket exhaust, that is, pretty big. The flare runs a bit longer, but it's really tiny compared to 7x BE-4s.
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