APOD: Back from Bennu (2023 Sep 29)

Comments and questions about the APOD on the main view screen.
User avatar
johnnydeep
Commodore
Posts: 2926
Joined: Sun Feb 20, 2011 8:57 pm

Re: APOD: Back from Bennu (2023 Sep 29)

Post by johnnydeep » Fri Oct 06, 2023 1:26 pm

miop wrote: Fri Oct 06, 2023 5:39 am Yes, push pins sounds good. And the Kapton tape holds the pins in place until the lid is attached to the venting hole. The white disc under the tape could be made of e.g. Teflon or ceramic. In case of Teflon the Tape will not stick very well, unless the surface would have been activated, with plasma or corona discharge. I'm thinking that the "sticker" is a prepared construction that is put on the hole in one piece, too.
The tape holds the pins in place? Isn't it the other way around?
--
"To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."{ʲₒʰₙNYᵈₑᵉₚ}

User avatar
alter-ego
Serendipitous Sleuthhound
Posts: 1120
Joined: Mon Apr 21, 2008 4:51 am
Location: Redmond, WA

Re: APOD: Back from Bennu (2023 Sep 29)

Post by alter-ego » Sat Oct 07, 2023 2:29 am

johnnydeep wrote: Fri Oct 06, 2023 1:26 pm
miop wrote: Fri Oct 06, 2023 5:39 am Yes, push pins sounds good. And the Kapton tape holds the pins in place until the lid is attached to the venting hole. The white disc under the tape could be made of e.g. Teflon or ceramic. In case of Teflon the Tape will not stick very well, unless the surface would have been activated, with plasma or corona discharge. I'm thinking that the "sticker" is a prepared construction that is put on the hole in one piece, too.
The tape holds the pins in place? Isn't it the other way around?
No, not necessarily. There now seems to be some method behind the "emblem" madness.
After yesterday's posts suggesting Kapton and push-pins, I reviewed my (previously posted) video for additional images that show new views, including which hole(1 of 2) are covered by the small lids, and found good prototype pictures in a video(July 2023) and another image here (selected images below).
  • I think that applying lengths of overlapping Kapton tape diametrically is most efficient on a circular disk as well a robust way to secure push-pins.
  • The backshell material (SLA-561V) is soft and can be removed by scraping with a plastic scraper so push-pins would work. The material has a Shore A hardness rating of ~30 which is about as soft as cork plugs.
  • As I said earlier, the large lid (and presumably small ones) is made of Teflon. It is flexible which also permits the two small lids to accommodate the backshell curvature. Ceramic would be much more difficult to implement on the curved backshell side.
  • On the large lid, the tape wrapped around the edges about 1 in, so the pins, being only ~1/2" from the edge, would pierce the tape ends. You can see how the disks can be preassembled such that the heads are under the tape, and the pins penetrate the tape wrapped ends thus providing a self-securing method for hold both pins and tape (especially when the lids are attached to the backshell). If the tape ends fill the perimeter edge of the lid, then every pin passes though Kapton.
     
    Prototype & Real Capsules.jpg
    Note: Re-entry charred the entire capsule black, and the resulting soot could easily come off as demonstrated when handled at the cleanroom facility. I believe the push-pins are necessary to secure the lid because tape only would not reliably stick to the powdery surface.
You do not have the required permissions to view the files attached to this post.
A pessimist is nothing more than an experienced optimist

User avatar
johnnydeep
Commodore
Posts: 2926
Joined: Sun Feb 20, 2011 8:57 pm

Re: APOD: Back from Bennu (2023 Sep 29)

Post by johnnydeep » Sat Oct 07, 2023 2:00 pm

alter-ego wrote: Sat Oct 07, 2023 2:29 am
johnnydeep wrote: Fri Oct 06, 2023 1:26 pm
miop wrote: Fri Oct 06, 2023 5:39 am Yes, push pins sounds good. And the Kapton tape holds the pins in place until the lid is attached to the venting hole. The white disc under the tape could be made of e.g. Teflon or ceramic. In case of Teflon the Tape will not stick very well, unless the surface would have been activated, with plasma or corona discharge. I'm thinking that the "sticker" is a prepared construction that is put on the hole in one piece, too.
The tape holds the pins in place? Isn't it the other way around?
No, not necessarily. There now seems to be some method behind the "emblem" madness.
After yesterday's posts suggesting Kapton and push-pins, I reviewed my (previously posted) video for additional images that show new views, including which hole(1 of 2) are covered by the small lids, and found good prototype pictures in a video(July 2023) and another image here (selected images below).
  • I think that applying lengths of overlapping Kapton tape diametrically is most efficient on a circular disk as well a robust way to secure push-pins.
  • The backshell material (SLA-561V) is soft and can be removed by scraping with a plastic scraper so push-pins would work. The material has a Shore A hardness rating of ~30 which is about as soft as cork plugs.
  • As I said earlier, the large lid (and presumably small ones) is made of Teflon. It is flexible which also permits the two small lids to accommodate the backshell curvature. Ceramic would be much more difficult to implement on the curved backshell side.
  • On the large lid, the tape wrapped around the edges about 1 in, so the pins, being only ~1/2" from the edge, would pierce the tape ends. You can see how the disks can be preassembled such that the heads are under the tape, and the pins penetrate the tape wrapped ends thus providing a self-securing method for hold both pins and tape (especially when the lids are attached to the backshell). If the tape ends fill the perimeter edge of the lid, then every pin passes though Kapton.
     
    Prototype & Real Capsules.jpgNote: Re-entry charred the entire capsule black, and the resulting soot could easily come off as demonstrated when handled at the cleanroom facility. I believe the push-pins are necessary to secure the lid because tape only would not reliably stick to the powdery surface.
Very nice analysis. Thank you!
--
"To B̬̻̋̚o̞̮̚̚l̘̲̀᷾d̫͓᷅ͩḷ̯᷁ͮȳ͙᷊͠ Go......Beyond The F͇̤i̙̖e̤̟l̡͓d͈̹s̙͚ We Know."{ʲₒʰₙNYᵈₑᵉₚ}