Parachute Model used by NASA

[whitelancer64]

I couldn't find a thread specifically about the inaccurate parachute modelling used by NASA, so I'm making one. I put it in the General discussion section because it applies to parachute use in general, and is not restricted to just Orion or commercial spaceflight.

As a brief summary, the main issue was that the loads on each individual line in a set of lines was assumed to be evenly distributed when actually it was not, especially in unsymmetrical parachute deployment. There's a PDF of a presentation about this that I will look for and put in the comments.

Elon Musk mentions (in the October 10th press conference at SpaceX headquarters, thread with videos here: https://forum.nasaspaceflight.com/index.php?topic=49241.0 ) that the MK 2 parachutes had lines made from nylon, and the MK 3 is going to zylon, which has something like 60 times greater tensile strength than nylon, and that the connection from the lines to the parachute material will be reinforced.

I'd actually like to know if anyone knows if that may have played a role in the parachute failures on the Ares I-X test flight. Would that even be something NASA would look into now?

Or for any other parachute failures in the past, like the larger supersonic parachute tested on the LDSD (Low Density Supersonic Decelerator) flights. Maybe even the Apollo 15 parachute failure.

[whitelancer64]

Found the PDF of the presentation on parachute modelling. It's called "CPAS Main Parachute Cluster Asymmetry: A Second Look" It contains references to a ton of other relevant work.

Originally found on this post (buried in the Dragon 2 update thread): https://forum.nasaspaceflight.com/index.php?topic=46136.msg1993863#msg1993863

[leovinus]

Found the PDF of the presentation on parachute modelling. It's called "CPAS Main Parachute Cluster Asymmetry: A Second Look" It contains references to a ton of other relevant work.

Originally found on this post (buried in the Dragon 2 update thread): https://forum.nasaspaceflight.com/index.php?topic=46136.msg1993863#msg1993863

Also, NTRS is your friend to find NASA documents related to "parachute".  I just looked and there are at least 5 documents from 2019 on parachute modeling.