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Author
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Topic: Retroreflector array on Endeavour underside
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David Carey
Member Posts: 782
From:
Registered: Mar 2009
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posted 11-06-2011 09:46 PM
   
When touring the VAB this weekend and getting some photos of Endeavour, I noticed all of the flash pictures revealed an array of reflective dots (seemingly retroreflectors as each "lit up" no matter the angle of incidence) on the vehicle's underside.I cannot figure out if these are part of post-flight modifications/preparations or something previously used in-flight for docking or approach imaging of the Shuttle underside by way of strobe or laser painting. Below is a picture of the effect; the dots were barely visible to the naked eye or flash-less photo but impressively mapped out the bottom surface when hit with the camera's flash. Curious to learn more if anyone knows - the tour guide was stumped.  |
ilbasso
Member Posts: 1522
From: Greensboro, NC USA
Registered: Feb 2006
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posted 11-08-2011 07:26 AM
I'm checking with my nephew, who actually supervised a few TPS scans from the ground on the final missions. My recollection is that the dots set a grid so that the arm does its sweep in straight lines, and also are used with the laser on the end effector to calibrate or ensure proper distance over the tiles and RCC on the leading edge surfaces. I'll post what my nephew has to say. |
ilbasso
Member Posts: 1522
From: Greensboro, NC USA
Registered: Feb 2006
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posted 11-08-2011 08:25 PM
Okay! So I was wrong! But the mystery deepens... From my nephew: They weren't there on orbit, I can say that for sure. Not only did I not see them, they couldn't possibly have survived reentry. They might be alignment spots for the RCS removal hardware or something else, but they are definitely not flown like that. For the TPS inspection on orbit, the group who does the analysis is actually pretty bad ass and just does it by counting the number of tiles from a given reference point like an RCS thruster. We occasionally do sharpie marks, permanent marker crosses and markings on the TPS, especially the nose cone, so the crew can make sure their cameras are pointed correctly, but that's the limit to which we modified the TPS. |
Ben
Member Posts: 1896
From: Cape Canaveral, FL
Registered: May 2000
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posted 11-08-2011 09:12 PM
I can confirm that these dots were added after their final missions. I regret to say that I asked what they were a few months ago and can't remember now. |
Jay Chladek
Member Posts: 2272
From: Bellevue, NE, USA
Registered: Aug 2007
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posted 11-09-2011 03:26 AM
I have to wonder if they might be taking some exact measurements of Endeavour for the museum in California to use in the design and construction of its final exhibit place. I would be curious to see if Atlantis and Discovery had them as well, or if this was something unique to Endeavour.Very weird. |
Robert Pearlman
Editor Posts: 42988
From: Houston, TX
Registered: Nov 1999
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posted 11-09-2011 08:44 AM
Here are two of my photographs of Discovery, taken in June, that show the same reflectors: 
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Jay Chladek
Member Posts: 2272
From: Bellevue, NE, USA
Registered: Aug 2007
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posted 11-09-2011 12:41 PM
Interesting. Are they taking the time to collect some final engineering measurements on the three orbiter airframes then while NASA still has them in their keep at KSC? |
nasamad
Member Posts: 2121
From: Essex, UK
Registered: Jul 2001
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posted 11-09-2011 03:40 PM
They look like the kind of dots put on people to do 3D motion capture, like with Andy Serkis as Gollum. Maybe someone is creating a 3D model. |
David Carey
Member Posts: 782
From:
Registered: Mar 2009
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posted 11-09-2011 08:41 PM
Jonathan; enjoyed meeting at AAMS. Thanks to you and your nephew for great information.A post-flight application seems to be the consensus and Robert's images confirm to my eye. Curious stuff and I bet the answer will end up being somewhere amongst the ideas here with 3D mapping/wireframing etc. If you click on the image and enlarge you'll note a clear underside delineation all the way out along the leading edge of the wing. Nosegear covers also decorated suggesting baydoor-closed profiling so maybe some clues there? In any case, it was nice to get a good look at the orbiter, and the VAB. |
Ben
Member Posts: 1896
From: Cape Canaveral, FL
Registered: May 2000
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posted 11-10-2011 02:36 PM
I got confirmation from an orbiter engineer that these reflectors are for optical scanning of the belly. But that's all I could find out. I'm not sure if it is just post-shuttle or if they have done this after other missions before as well, which may be the case. |
mjanovec
Member Posts: 3811
From: Midwest, USA
Registered: Jul 2005
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posted 11-10-2011 05:19 PM
For comparison to Robert's photos of Discovery, here is the same area of Endeavour I photographed in November 2010, while it was in the Orbiter Processing Facility Bay 2 being readied for it's final mission. |
Spaceguy5
Member Posts: 427
From: Pampa, TX, US
Registered: May 2011
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posted 11-10-2011 08:05 PM
Obviously they're taking some sort of measurements of the airframe, although that seems odd to me with the program finished. I remember similar was done with the X-38 after its landing tests, link here. |
MCroft04
Member Posts: 1634
From: Smithfield, Me, USA
Registered: Mar 2005
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posted 11-10-2011 08:44 PM
All my pictures have the dots too. I thought it was my camera. |
David Carey
Member Posts: 782
From:
Registered: Mar 2009
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posted 11-11-2011 09:48 PM
Thank you Ben. I appreciate you taking time to get some first-hand information on this. Spaceguy5's X-37 link was really interesting, and worth a read. Makes me wonder if they are looking to map changes between as-built and retirement due to landing cycles (though it's disconcerting to imagine things moving too much!). |
Ben
Member Posts: 1896
From: Cape Canaveral, FL
Registered: May 2000
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posted 11-13-2011 12:21 AM
It's only speculation, but they may be wanting the most advanced 2011 imaging for archival and engineering purposes, for future reference, before they are handed to museums and they don't have the ability to do it again with ease.If I am able to find out the exact reason I'll be sure and follow up here. |
SpaceKSCBlog
Member Posts: 119
From: Merritt Island, FL
Registered: Nov 2011
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posted 11-23-2011 05:05 AM
My wife took the tour on November 20 and got the same result. |
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