Is there any information on which parts of the falcon are predicted to wear out fastest?
Quote from: gin455res on 08/19/2017 07:15 amIs there any information on which parts of the falcon are predicted to wear out fastest?Well, for stuff we know wears out - crush cores in the legs, fairing and second stage are both one-use, as well as payload adaptors.At least some, perhaps most of the ablative under the engines covering 'stuff' seems likely to at least need monitoring if not replacement every flight.The grid fins used to wear quite a lot - titanium may wholly fix this.NASA have expressed concerns about cracking in turbopump rotors, but it's not clear if this is a wear item.The paint often seems rather torn up.
A friend at SpaceX (who is extremely closed-mouthed about everything) said that one thing he could tell me is that you will recognize a Block 5 first stage instantly by the heat shields around the base - it's going to be all Inconel.
If they don't mind a little mild radioactivity, they could instead use HK31, an alloy of magnesium, thorium, and zirconium which is no longer in use since the three percent that is thorium makes the alloy radioactive.It's much lighter and reradiates heat faster while still retaining the same thermal capacity.
In the 1970's we were calibrating a scintillation counter with a source. When the source was withdrawn, there were still counts. Traced it back to the brick walkway and mentioned it to the facilities people after lead shielding the side of the wall so we could get on with the instrument work.
One of the costs of refurbishment of the Shuttle's TPS was the need to address the multiple elements of its design and fabrication, for it to function on the next flight. Hot structures don't just function by themselves, you need to have supports and means to isolate / attach them. Even the choice of materials / alloys can become critical to such.
Heat capacity and convection/conduction of materials matters a great deal, as well as the means to support repeatable use, possibly w/o refurbishment.
Earlier use of thoriated alloys allowed for some of these options, which is why it was brought up, as an alternative to much more heavy inconel. An old trade for those that remember it.
]Not to mention some of the work the DLR did also on metallic heat shields for X-38.
The family was developed so that you could alter both the ceramic substrate material and thepolymer impregnant. You could optimize the material for whatever application you had in mind.”“It turns out that PICA had a higher heat ablative performance which was of interest to SpaceX, butthey also use a variant of SIRCA on the back shell which they call XIRCA, a flexible silica blanketthat has silicone impregnation”, Rasky told us. SpaceX developed PICA-X, a version of NASA’s PICA,to protect the Dragon spacecraft on its return to Earth"
"PICA heat shieldRasky had been a key part of the PICA-X carbon tile, without which there would have been no MarsCuriosity on Mars in 2013.I was curious about the applications of such a material in electronics or semiconductor processessuch as a heat shielding material that might be used in conjunction with a heat sink in hightemperature areas. I asked Rasky if such an application has been found. Rasky replied that, yes, theone for electronics is a cousin to PICA called SIRCA, that is, Silicone Impregnated Resuable CeramicAblator. It’s a silica-based tile with silicone impregnation. It’s RF transparent and non-conductive, sounlike the carbon-fiber PICA material, it would not conduct electricity or block RF signals. TheSIRCA material would be good around antennas in that it would not interfere with the RFtransmission/reception.Rasky continued, “So SIRCA is a sort of ‘sibling’ to PICA. They were developed as a family of what’scalled a lightweight ceramic ablator that started with ceramic substrates. So you could use a silicasubstrate or a carbon substrate and then add in a polymer impregnant that you can add in. In effect,you add silicone into the silica substrate and get SIRCA; you add phenolic to the carbon substrateand get PICA.The family was developed so that you could alter both the ceramic substrate material and thepolymer impregnant. You could optimize the material for whatever application you had in mind.”“It turns out that PICA had a higher heat ablative performance which was of interest to SpaceX, butthey also use a variant of SIRCA on the back shell which they call XIRCA, a flexible silica blanketthat has silicone impregnation”, Rasky told us. SpaceX developed PICA-X, a version of NASA’s PICA,to protect the Dragon spacecraft on its return to Earth"
Is that pieces of the nozzle that was cut out for analysis, or am I seeing things?
There seem to be also holes(*) in the part of each engine bell closest to the outside of the rocket, at the very ends.And the cutouts(holes?) don't go all the way through - as the shadows for the right-hand-side of the image are wrong, as is the background of the shadowed area. Could this be a thermal layer over the bells?https://twitter.com/ses_satellites/status/931083202705461248 - coincidentally, presentation of flown bits of SES10, of a size possibly consistent with the above cutouts.
OT, but Elon seems to be going grey. Presumably, Model 3 production is taking its toll...