Miss Dada  🏳️‍⚧️

okay, here's something I've never understood: in many articles about re-entry, there's the blurb about the angle needing to be exactly right - too steep, you burn up, too shallow, you skip back into space but why is skipping "catastrophically bad", as one article puts it??

all the reasons I can think it's bad don't really make sense. seems like the heatshield should be fine, as there's still the same amount of energy being absorbed. sure, you're going to be landing where no one expected, with no recovery crew, but that seems survivable.

hitting land with a water-based landing system probably isn't great, but that still seems nonfatal (if unpleasant). is the "danger" blurb all just incorrectly carried over from apollo, where skipping means a potentially still-elliptical orbit and life support would run out?

Gotcha, thanks! Yeah, the minor thermal load for long periods of time seems potentially bad, I'm obviously not a heatshield expert, haha. although I'm side-eyeing "generates little or no lift", makes me doubt the article a little - e.g. apollo's 0.368 L/D is not insignificant

Yeah, I don’t know enough about rocket science to say anything about that I can imagine @sgrif knowing more.

Skipping isn't necessarily catastrophically bad depending on the orbit, but if you skip on a lunar re-entry that can mean many hours or even days before re-entry. The service module was jettisoned at this point, so that can be bad. More generally it's about thermal load though

The shallower your re-entry the more thermal load overall the craft will have to endure, but in exchange you will have less peak heating. More thermal load means you need more ablative heat shielding, meaning more mass, so you want to have the steepest reentry you can survive