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Artemis II safely splashes down
341–350 of 475 posts
Re: Artemis II safely splashes down
#342Earlier quoted context omitted.
2.4% is not bad given how new this still is and how extreme the speeds and energies are. Note that all the fatalities have been launch or landing related, not in space itself. Clawing out of this gravity well is tough. Make Earth a bit larger and you’d never get off it without something like NERVA or nuclear pulse Orion. I wonder sometimes if that’s another thing to toss in the Fermi paradox bucket. Many rocky planet…
NERVA as envisioned had terrible thrust to weight ratio, not really usable to launch from a Super Earth. Nuclear lightbulb, orion or heck NSWR would likely work though. And bonus points for not having to think about landing systems for the return trip. ;-)
In that case aliens from a super Earth would be unable to get off it unless they decided to salt their biosphere with fissile waste. NERVA is at least contained if it works properly.
So no space program from a super Earth until they figure out not just fusion but compact high density fusion that could fly. You’d need stuff like in The Expanse, or at least in that rough ballpark.
Using fission is something they probably wouldn’t do unless they faced an existential reason forcing them to go to space, like deflecting an asteroid.
Re: Artemis II safely splashes down
#343Earlier quoted context omitted.
2.4% is not bad given how new this still is and how extreme the speeds and energies are. Note that all the fatalities have been launch or landing related, not in space itself. Clawing out of this gravity well is tough. Make Earth a bit larger and you’d never get off it without something like NERVA or nuclear pulse Orion. I wonder sometimes if that’s another thing to toss in the Fermi paradox bucket. Many rocky planet…
The lack of plate tectonics is a much bigger obstacle on Super-Earths, then g.
Yeah the more I learn the more I buy the rare Earth explanation.
Life may not be that unusual but it might be mostly just goo: little extremophile type bacteria and maybe very tiny creepy crawlies living in deep seas, underground, in liquid mantles in ice moons, etc.
But to get stuff even as sophisticated as frogs and bunnies, let alone something that can try space flight, requires a place that is all of: big, stable, with abundant energy, with high enough metallicity, and in an environment well shielded from flares and impacts.
There may not be a lot of places like this.
Re: Artemis II safely splashes down
#344Has NASA (or anyone) said anything about how the heat shield performed?
Re: Artemis II safely splashes down
#345Earlier quoted context omitted.
> Artemis acceptable crew mortality rate is 1 in 30. This seems insane to me. That X decades later we accept, with all our advancements in tech, a weaker system than ever before. That if we send 30 people we _accept_ that one is possible to die. That's the starting point? That's what we document as acceptable?
Yes, and the memories of Apollo are made rosy by hagiography. I even wrote an entire thing to explain why, https://1517.substack.com/p/1-in-30-artemis-greatness-and-ri... (yeah, shameless plug, sorry - it's more for the citations than not. You can read the standards and reports I've linked to) But if I'm allowed to repeat myself from elsewhere in the thread and the meat of the above thing, It's physically not possibl…
> We're a very primitive species,
compared to what? We're the most advanced species we know of.
It might even hold true over the entire universe. All species might top out at where we are. We don't know.
Re: Artemis II safely splashes down
#346Earlier quoted context omitted.
Nice article, although I'm not so sure about this part: > There’s a reason why there wasn’t an Apollo 18, or 19 and 20. Even though funding had been secured, an executive decision was made to kill the program early, because LoC was inevitable. Was funding really secure? I believe that was the main sticking point; a quick search [0] seems to confirm this, and the John Young quote below backs it up: "Even if they’d had…
> Was funding really secure? It's worth breaking down what the "funding" means over here. As this is a depressing topic for me, I'm going to be a bit playful. :) The Saturn V's existed. Saturn V serial numbers were designated as S-5## where # is an increment from 1. https://en.wikipedia.org/wiki/Saturn_V#Launch_history SA-513 was repurposed from Apollo 18 to Skylab. SA-514 was meant for Apollo 19. They put it on disp…
Thank you for the in depth reply! You make a very good point, and the timing of Apollo 13 with the budget decision is pretty damning, I'm convinced.
I will point out however that the budget was congressionally-mandated, and no funds were allocated for moon landings as they were in previous years; it would have been illegal to use funds dedicated to other areas for moon landings. Maybe I'm being overly pedantic here, but to say the 'funding was secured' as in the article implies the decision to cancel the remaining programs lay with NASA leadership; it would be more accurate to say that funding for the remaining programs, though possible, was not secured, most likely as an attempt to save face by congress/govt.
Re: Artemis II safely splashes down
#347Earlier quoted context omitted.
NERVA as envisioned had terrible thrust to weight ratio, not really usable to launch from a Super Earth. Nuclear lightbulb, orion or heck NSWR would likely work though. And bonus points for not having to think about landing systems for the return trip. ;-)
In that case aliens from a super Earth would be unable to get off it unless they decided to salt their biosphere with fissile waste. NERVA is at least contained if it works properly. So no space program from a super Earth until they figure out not just fusion but compact high density fusion that could fly. You’d need stuff like in The Expanse, or at least in that rough ballpark. Using fission is something they probab…
I think a launch loop would still work, even on a Super Earth:
https://en.wikipedia.org/wiki/Launch_loop
Or potentially beamed power for launch, so you don't kug a power source. But in any case, indeed much harder. :)
Re: Artemis II safely splashes down
#348Earlier quoted context omitted.
Yes, and the memories of Apollo are made rosy by hagiography. I even wrote an entire thing to explain why, https://1517.substack.com/p/1-in-30-artemis-greatness-and-ri... (yeah, shameless plug, sorry - it's more for the citations than not. You can read the standards and reports I've linked to) But if I'm allowed to repeat myself from elsewhere in the thread and the meat of the above thing, It's physically not possibl…
That was a great article. Adding to it - Apollo 13 was a mission where 3 men should have died, but somehow didn't. If it had happened while the LM was on the moon, you would have had the CSM lose power, and then two men on the moon would have had no way to return home. (And for the shuttle design mission - my understanding is it was likely the ability to do a HEXAGON-style film return mission in a single orbit, befor…
That would have been absolutely horrible
Re: Artemis II safely splashes down
#349Earlier quoted context omitted.
> It's physically not possible at our current level of technology to make this "safer" due to the distances and energies involved. That's not true at all. It is entirely within current technical and fiscal means to launch a much more robust and powerful craft that is capable of goign to the moon and returning with lower velocity by sending it up in pieces with Falcon 9 (Heavy) and assembling it in LEO before launchin…
Given current levels of technology, this would require docking with a series of space tugs. Not impossible, but Blue Origin is the only organisation working on this at a meaningful scale. There was also Nautilus-X which never made it beyond the concept stage.
Mir and the ISS were built this way and the Space shuttle, Dragon, and Soyuz have/had no problem docking with the ISS.
If you feel constrained by the size of the Falcon Heavy fairing the now defunct Bigelow Aerospace launched several prototype inflatable habitats that apparently tested well in LEO.
Combine this with a lunar cycler[0] orbit and you could keep reusing the same craft over and over and expanding to it if you want to ferry the astronauts to the moon.
You'll note that everything I'm describing requires existing technology and very proven techniques (except maybe the inflatable stuff) but the thing it doesn't require is a giant rocket like SLS or Starship. I'm not saying that we shouldn't build machines like that, it's just that they really aren't needed for a mission like this and I question why something like SLS was built in the first place.
Re: Artemis II safely splashes down
#350As a long time space nerd, I'm not sure what this accomplishes by repeating the previous stunts that failed to usher in the promised space frontier. Apollo was, IMO, not successful at changing the course of human history. A really cool footnote, sure, but everything else that was to follow, nope, just a bunch of neat, interesting but ultimately meh science missions. An exciting change would be more like Delta-V/Criti…
What is delta v/critical mass?
Fictional books about asteroid mining, from what my Google searches are returning. I would love to learn that it was a real thing though