NASA should have known about the cost differences well before they built the AVCOAT version. The contractor would have bid manual labor for filling the holes, which if you have watched the video was very laborious (and not very consistent). If cost was an issue they would have gone with the tiles to start.
Quote from: Lars-J on 09/25/2015 05:15 pmQuote from: b0objunior on 09/25/2015 12:50 pmhttp://www.nasa.gov/feature/nasa-applies-insights-for-manufacturing-of-orion-spacecraft-heat-shieldHeatshield made out of multiple pieces. We knew that but it's fun to look at it for the first time.Yep... I attached an image from the link.Heatshield tiles? Who would have thought? And so one of the main arguments for Avcoat (vs PICA) is chucked out the window.Lets not forget that the decision to use AVCOAT over PICA was made long before something the size of Dragon used it as a heat shield. The fact is AVCOAT will work just as well and it is good that NASA is making improvements to lower the cost and manpower needed to make the heat shield.
Quote from: b0objunior on 09/25/2015 12:50 pmhttp://www.nasa.gov/feature/nasa-applies-insights-for-manufacturing-of-orion-spacecraft-heat-shieldHeatshield made out of multiple pieces. We knew that but it's fun to look at it for the first time.Yep... I attached an image from the link.Heatshield tiles? Who would have thought? And so one of the main arguments for Avcoat (vs PICA) is chucked out the window.
http://www.nasa.gov/feature/nasa-applies-insights-for-manufacturing-of-orion-spacecraft-heat-shieldHeatshield made out of multiple pieces. We knew that but it's fun to look at it for the first time.
The CEV was originally scheduled to fly with a PICA heatshield.
For more than three years, NASA's Orion Thermal Protection System Advanced Development Project considered eight different candidate materials, including the two final candidates, Avcoat and Phenolic Impregnated Carbon Ablator, or PICA, both of which have proven successful in previous space missions.
Quote from: woods170 on 10/22/2015 09:06 amThe CEV was originally scheduled to fly with a PICA heatshield.Where do you get that? From one of the sources you yourself provide, the 2009 Florida Today article:Quote For more than three years, NASA's Orion Thermal Protection System Advanced Development Project considered eight different candidate materials, including the two final candidates, Avcoat and Phenolic Impregnated Carbon Ablator, or PICA, both of which have proven successful in previous space missions.
The switch to AVCOAT took place three years later.
Lockheed wants to use the Phenolic Impregnated Carbon Ablator developed by NASA Ames and used for Lockheed's cometary-dust capturing Stardust capsule, which returned to Earth in January. McKenzie says: "We have baselined for the TPS the Stardust capsule material."Ames researchers expect that whichever potential TPS option is selected at the Orion PDR, it will be ablative.
Quote from: woods170 on 10/22/2015 12:48 pmThe switch to AVCOAT took place three years later.Ah, thanks! That makes sense from Lockheed Martin's perspective. From NASA's perspective, though, wouldn't the decision have been "made" at the PDR milestone rather than at the contract award?
What about the airbags? Weren't they deleted to fit the payload capacity of the Ares I? Why couldn't they be replaced when the SLS became the LV?
Quote from: vulture4 on 11/15/2015 07:25 pmWhat about the airbags? Weren't they deleted to fit the payload capacity of the Ares I? Why couldn't they be replaced when the SLS became the LV?The airbags were deleted in an early DAC of Orion. The DAC's had been all but completed by the time Orion was repurposed to fly on SLS.It is not exactly easy to fit things back into a design that has evolved considerably from the original design.
Land recovery was originally chosen because it reduced cost and risk. I would have thought the decision to abandon it would be reconsidered when the reason for the decision went away. Maybe I am just naive.
These are also available on NASA's Orion Flickr page!
The NASA article states that a metallic coating will be bonded to the backshell tiles:"For these future Orion missions, a silver, metallic-based thermal control coating will also be bonded to the crew module’s thermal protection system back shell tiles."When they say "a coating", it makes me think that each tile will be individually silvered during the manufacturing process. But the renderings make it look like a silver film is applied in large sheets to the backshell. And actually the graphics make it look like more substantial metallic sheets are riveted to the backshell, not just a film or coating.So does anyone know if this reflective coating will be "painted" on the tiles individually, applied as a film to the backshell, or installed as heavier panels secured mechanically to the backshell?Thanks.