idlewords

I think you mean Artemis IV (the moon landing)? Artemis III is now a near Earth orbit mission to dock with whatever mockup lander SpaceX or Blue Origin can throw up in time.

The next two Soyuz launches are this Wednesday and Saturday.

You would be the first person to ever accuse the Orion program of cutting costs.

If you play a single round of Russian roulette with a revolver, it is likely you will not die, but it is also not safe to do that. The same idea applies here.

The foam shedding/impact problem was heavily analyzed throughout the Shuttle program, and recognized as a significant risk. Read the CAIB report for a good history.

That report also describes the groupthink dynamic at NASA that made skeptical engineers "come around" for the good of the program in the past. Calling Camarda an outlier is just a different way of stating this problem.

The Apollo command module used Avcoat, the same material as Orion. But there are two key differences:

1. The application method is different. Apollo applied it to a metal honeycomb structure with very small cells, while Orion uses blocks of the material. (NASA tried the honeycomb approach for Orion, but it was too labor-intensive).

2. Orion is much bigger and heavier than the Apollo command module. The informal consensus is that Apollo may have been at the upper size limit for using Avcoat.

They do iterative flight testing. Starship is I believe on its twelfth flight test; the first one was in 2023.

It couldn't, for a funny reason. Everything on a Shuttle flight could be automated except lowering the landing gear just before touchdown, which had to be done by hand from inside the cockpit.

There are rumors (that I've never been able to run down) that the astronaut corps insisted on this so the Shuttle could not be flown unmanned.

The Orion heat shield is sixteen feet across. NASA's test facilities can only test small material samples in these facilities, not capture how the entire heat shield will behave.

Getting on the train that's physically in front of you, no matter how crowded, is the rational decision basically everywhere outside Japan, where you can have metaphysical certitude that the next train will show up as scheduled.

Grug use few words, make it easy read grug.

The style is the most charming part of this essay.

And for the lazy, there's the 1:1 scale model under your feet.

The universe is a UI nightmare

An exponential curve looks locally the same at all points in time. For a very long period of time, computers were always vastly better than they were a year ago, and that wasn't because the computer you'd bought the year before was junk.

Consider that what you're reacting to is a symptom of genuine, rapid progress.

My blog is static files. It preserves a moment in time when PHP was complaining, forever.

Reading Graham's essays on writing always puts me in mind of the videos where Mexican moms react to Rachael Ray trying to cook (https://www.youtube.com/watch?v=zFN2g1FBgVA), or a Malaysian guy has to watch a BBC cook make rice (https://youtu.be/53me-ICi_f8?si=0AaZ82dk_AYFqJAx&t=226).

What's the useful part of Pocket's feature set that doesn't overlap with Pinboard?

I'll take it off their hands.

In this thread: all the difficult employees

Great, now who is going to bring back web rings?

Discoverability remains the one great problem of online self-publishing. A history of how solutions have changed over the years would make for a fun history of the web.

The 2-3x uncertainty in tumor risk comes entirely from the heavy ion component of GCR. Please go back and re-read that section of my post if you need to.

1) Radiation

2) Partial gravity

It does not; see the paper cited in my other reply to you. GCR dose is 1.5-2x on Mars compared to ISS.

The mention of "quality factor" here just begs the question. The reason we need research on biological effects of high-Z ion exposure is that it has a different mechanism of damage, not captured by that paradigm.

I didn't choose AL shielding as the reference standard to use in the literature; I'm sorry it bugs you.

You can read the author's other work, that goes into great detail about different types of shielding, if you want to gain confidence in his math. The upshot is you need many meters of polyethylene to effectively shield the heavy ion component of GCR, which is what the fuss is about.

But the point of that particular diagram is not shielding, but to illustrate the 2-3x uncertainty in estimates of tumor risk based on our poor understanding of high-Z ion exposure.

Total GCR dose is 3-5x in transit to Mars compared to what you get on ISS; on the Martian surface it's from 1.5-2x the ISS dose. (see https://www.swsc-journal.org/articles/swsc/pdf/2020/01/swsc2...).

On a long-stay Mars mission, that adds up to 12-18 times the accumulated GCR exposure compared to a six-month ISS increment.

No one has ever done a "years long" expedition to ISS, and the radiation flux in transit to Mars, in particular GCR dose, is much higher than experienced on the space station.

I think you misunderstood a diagram; grams of Al per square centimeter is a standardized unit of shielding in the literature, not an engineering choice.

Solar electric propulsion has great specific impulse [i.e., efficient use of propellant] but very low thrust. You're forever spiraling away from and then down into gravity wells.

It's terrific for cargo, but not viable for crews.

Have either of you ever met a five year old?

Where are those families now?