Earth Return & Sample Science Options

[nprev]

Now that the 'boop' has been completed (with spectacular success!), we'll move the discussion to here for subsequent mission events.

[rhr]

There's a publication up:
Asteroid (101955) Bennu in the Laboratory: Properties of the Sample Collected by OSIRIS-REx

https://arxiv.org/abs/2404.12536

[rlorenz]

There's a publication up:

There's a nice reference in that scientific preprint to a reconstruction analysis of the EDL at NTRS

Things weren't quite as complicated as I speculated back in (post 116), as there had been a press statement about altitude that was spurious*. No need now, I think, to invoke the dynamic pressure I wondered about.

The lines to the main deploy/drogue release pyro and the drogue deploy mortar were switched.

The first firing was 14 seconds after a g-trigger (downgoing 3g), the second firing was to be 363 seconds after that trigger, or when a pressure sensor saw 10,000ft above sea level, whichever condition was met first.

The first firing effectively caused nothing to happen, since both drogue and main were still buttoned up in the capsule, except the line from drogue to capsule was severed.

The capsule was then falling faster than planned (no drogue!) and tumbling, until the pressure trigger fired (only 212 seconds after the g-trigger). Mortar fired throwing out the drogue which pulled out the main as it was dragged away. Although the main deployed at a higher dynamic pressure than intended (and at a who-knows-what attitude), it fortunately did so safely.

Kudos to the team for writing up these details so they can be learned from.

Ralph

(*Francis Crick : "Any theory that fits all the facts will be wrong, because some of the facts will be wrong")