I’m not sure that I would say “better” – the engineer in me says “lighter, more fragile”. To me everything has it’s up and downs – the question is, for a given application, what are the pluses and what are the minuses.

In the case of Orion, it seems to me that an attempt to reduce risk by going with the known – AVCOAT, tractor LAS, Apollo shape scaled up etc has actually increased the combined risk of the design.

The gap filler issues were solvable – NASA has been looking with great interest at recent testing

http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20090007607.pdf

and

http://www.planetaryprobe.org/sessionfiles/Session7A/Posters/Stackpoole-Poster.pdf

PICA was baselined for Orion as NASA was trying to revive AVCOAT. Once they believed they had AVCOAT they went with it since the thing already flew with Apollo and they thought they understood it better…

Hope this helps.

Ballistic entry coming from LEO gives you anywhere from 10 to more Gs, coming from the Moon or elsewhere… Ballistic entry are abort entries. Go ask Soyuz. Anyway.

The entry profile is and has always been called called a skip entry. But this is a concept that seems foreign to you. In what way does a skip entry reduce the entry interface velocity? A skip is merely there after you have done a first dip into the atmosphere at the problematic heat rates. And the duration of the skip influences the heat loads so yet again the mass of the heat shield.

Aerobraking will not help you much – not with current technology as used on Orion – since as I was trying to explain to you the heat load ends up being much larger than on a direct skip entry. It would result on smaller heat rates and much larger heat loads. Again heat loads drive the thickness of your heat shield, hence mass.

So getting there or still very difficult? Ah Cornell… Maybe it’s the street of the University you went to?

“Yeah, just like Ares I-X would crash into the tower at launch, or would shake to pieces on ascent, couldn’t be guided because of its length, or…”

All concerns that NASA itself had identified, and which the Ares I-X flight was to provide data about – that’s how science and engineering works.

And NASA has publicly stated that they as yet don’t have a solution for the weight issue on Orion/MPCV, and that they will be fighting the weight issue up until the EM-2 flight. Jim Hillhouse of AmericaSpace himself asked NASA representatives that question at a press conference last year, as he is a HUGE SLS & Orion fan, yet he didn’t publish the response he got on his own publication. It’s OK if he ignores the weight issue, but it’s not OK for NASA to ignore the issue if peoples lives are at stake.

I’m not sure you have the right priorities here…

Multi-pass re-entry has been ruled out by NASA in the past as too risky – if you get it wrong by a rather small amount you are in deep, unrecoverable sh&%.

High speed re-entry is a known, solved problem – see Stardust.

Orion simply doesn’t have a thick enough heat shield to return from beyond the moon. Due to weight issues, it may not be up to a lunar return either.

In addition PICA is more efficient as a heat shield material – so weight can be further reduced.

PICA got tested at 12.9 km/s (the fastest reentry ever) for Stardust…..

https://smartech.gatech.edu/handle/1853/26427 – states (ironically) that –

“It is noted that the post-flight analysis of the Stardust heat shield is especially important since PICA is baselined for both the Orion (CEV) and Mars Science Laboratory vehicles.”

‘I’d put it differently. There is a new success mode.’

Heating cryogens gives you some fun failure modes – BLEVE or bubbles in the liquids going into your turbo pumps.