Hi,Is there a link to the actual RFI?...
I'm curious about what you all think could be different and still meet that huge list of specs because they basically printed out the full spec list for the OMS as requirements. Materials selection (3D print, different alloy, etc...) is my only guess but I would still consider that the same engine.
Quote“The specific objective of this RFI is to solicit information that may potentially enhance NASA’s planned approach for an OMS engine replacement, including engine subassembly, nozzle extension, and heat shield assembly, and assist in developing the acquisition strategy,” notes the RFI document.Moreover, NASA’s RFI also states that “This RFI is not to be construed as a commitment by the Government nor will the Government pay for information solicited. NASA will use the information obtained as a result of this RFI on a non-attribution basis. The information received may be used in developing the best approach for fulfilling these requirements, and therefore, may be recognizable to the interested party.”It’s like the meeting to plan the planning meeting. So much red tape...
“The specific objective of this RFI is to solicit information that may potentially enhance NASA’s planned approach for an OMS engine replacement, including engine subassembly, nozzle extension, and heat shield assembly, and assist in developing the acquisition strategy,” notes the RFI document.Moreover, NASA’s RFI also states that “This RFI is not to be construed as a commitment by the Government nor will the Government pay for information solicited. NASA will use the information obtained as a result of this RFI on a non-attribution basis. The information received may be used in developing the best approach for fulfilling these requirements, and therefore, may be recognizable to the interested party.”
Like nobody thought "Hmmm, we have a finite number of these engines, we'll someday run out of them if we keep shooting them out into space and not bringing them back. Do you think that once the program starts, we'll need to redesign replacements for all this legacy stuff? - Nahhhh!"The thought that this was all sold as being cheaper and faster because you would be using 'off-the-shelf' components is just mind-boggling.
And it does make sense. Minimize the amount of development dollars needed at one time by using the assets you have first. And yeah, the engine will essentially be the same because the prop system on the SM is designed to meet the inlet conditions needed for that engine. But there are some things that could change, namely materials and manufacturing techniques that would reduce the recurring cost of the engine.
Am I the only one that read that as:"We are asking for information to see who wants to start building the OMS engine again."The specifics are so specific that the only engine that could replace the OMS is the OMS.I'm curious about what you all think could be different and still meet that huge list of specs because they basically printed out the full spec list for the OMS as requirements. Materials selection (3D print, different alloy, etc...) is my only guess but I would still consider that the same engine.
So, is this just another effort to justify starting up an old AJR line at huge expense like the RS-25E 'justification'?
Ok, this thread has completely de-railed into NASA and SLS/Orion bashing per usual...
Quote from: Khadgars on 02/16/2018 10:52 pmOk, this thread has completely de-railed into NASA and SLS/Orion bashing per usual...No. This is the AJRD-bashing thread. The NASA and SLS/Orion bashing thread is the next door down on the left.
Quote from: AncientU on 02/16/2018 08:51 pmSo, is this just another effort to justify starting up an old AJR line at huge expense like the RS-25E 'justification'?On a more serious response.The SuperDraco, while clearly not fitting, is at least in the ballpark.I would be very, very surprised if SuperDraco cost $1B to develop, and a third hypergolic engine might be well within their demonstrated capability.
Quote from: ReturnTrajectory on 02/16/2018 07:53 pmAnd it does make sense. Minimize the amount of development dollars needed at one time by using the assets you have first. And yeah, the engine will essentially be the same because the prop system on the SM is designed to meet the inlet conditions needed for that engine. But there are some things that could change, namely materials and manufacturing techniques that would reduce the recurring cost of the engine. It WOULD make sense if they just basically started making the exact same engine again. But they won't. There will be some oh so very slight changes, which will require full on development, then full on testing, then full on certification, and then next thing you know....somewhere in the books will be a line item for Orion Service Module engine re-dev with probably 9 numbers to the left of the decimal place.Where do I get this from? The RS-25 engines. They used them for the same exact reason as the OMS (legacy hardware reuse), woops...we are going to run out so we need to make more....we want costs to go down...lets change it to save money...now we have to re-develop/re-test/re-certify the expendable version...and if it only costs a few million less per engine then the original(complete guess...no soild numbers known!!)... and dev/test/cert...costs say 1 billion for easy math....it would take 500 engines to just break even from the changes made.For using the same design to save costs...they are sure having to dump a lot of money into the develop/test/recertify part which is where they say they are saving the money in the first place!! I see no reason to believe the OSM re-engine will not follow the path of lots of money to get it going again.My problem is not with the money they are having to spend to basically restart the production lines...I have no issues with that...it has to be done. My problem is with them saying "We are reusing to save costs, but then we are modifying things to be cheaper." That is creating more dev/test/cert costs that I believe outweigh what they are trying to save by reusing existing hardware in the first place.If Dev+Test+Cert+New Item < Original Item on costs, then yay..saved money.But if it's > (which i believe it will be on quite a few parts)...then boo...wasted moneyTime will tell....
Meanwhile, in preparation for the potential ISS 2021-2024 contribution deal, European technical studies this year will assess avionics, habitation modules and life support systems for a cislunar habitat and new propulsion options for the Orion service module.The study of new propulsion options for the service module is being done because the module uses the space shuttle’s orbital maneuvering system (OMS) engine and its supply is limited. “There are propulsion trade-offs for how to enhance [the propulsion system] for the long-term,” Parker said Feb. 3.Parker expects the first three service modules to use the OMS, which uses the fuel monomethyl hydrazine and the oxidizer, nitrogen tetroxide and produces 6,000 pounds of thrust. ESA is considering four alternate engines, Dettman told SpaceNews in a Feb. 3 interview, but he declined to say which engines. One possible alternate hydrazine engine is the Aerojet Rocketdyne AJ10-118k. It produces a 9,850-pound thrust at altitude and was used for the second stage of United Launch Alliance’s Delta 2 rocket.
Isp (specific impulse) ~ 310 (minimum), standard inlet conditionsThrust ~ 6000 lbf, standard inlet conditionsMR (mixture ratio) ~ 1.65Weight ~ 284 lbf (maximum)
If a replacement engine goes ahead, who pays for it for each flight, NASA or ESA?
Let's speculate. The required specs from the RFI:310 s ISP min. Aestus 3178 Ns/kg which is 324 s......CHECK6000 lbf thrust min = 26,7 kN. Aestus has 28,4 kN...CHECKMR ~1,65. Aestus uses an MR of 2,05......................MAYBE?284 lbs max = 128,9 kg. Aestus has 111 kg.............CHECK
