I did a quick render here to show the arrangement in the aft compared with the (more exposed) CAD diagrams of the area from NASA.
Quote from: okan170 on 08/01/2017 04:56 pmI did a quick render here to show the arrangement in the aft compared with the (more exposed) CAD diagrams of the area from NASA.What is the source of that CAD picture?
I revisit the DSG pdf, and realize in the plan drawing, the only module connected with PPE is Hab (using rear port of Hab). Since Hab has 3 ports in total, front/rear/side, that leave 2 ports available to be used, not blocking station keeping thruster....
HEO Committee power point on Future Exploration Plans by Greg Williams has been posted, including several slides on the PPE https://www.nasa.gov/sites/default/files/atoms/files/nac_exploration_july_2017_4-2.pdf
Quote from: BrightLight on 08/01/2017 02:44 pmHEO Committee power point on Future Exploration Plans by Greg Williams has been posted, including several slides on the PPE https://www.nasa.gov/sites/default/files/atoms/files/nac_exploration_july_2017_4-2.pdf Is PPE (and ARM) still unfunded in NASA's 2018 budget, suggesting this RFI and assumptions about a DSG in NRHO are merely castoff program dreams? Is it better to wait until a new, actually viable plan is put forth to speculate on DSG and Lunar operations?
Quote from: Propylox on 08/05/2017 03:34 pmQuote from: BrightLight on 08/01/2017 02:44 pmHEO Committee power point on Future Exploration Plans by Greg Williams has been posted, including several slides on the PPE https://www.nasa.gov/sites/default/files/atoms/files/nac_exploration_july_2017_4-2.pdf Is PPE (and ARM) still unfunded in NASA's 2018 budget, suggesting this RFI and assumptions about a DSG in NRHO are merely castoff program dreams? Is it better to wait until a new, actually viable plan is put forth to speculate on DSG and Lunar operations?Not everything that NASA launches has specific funding. Space technology and Advanced Explorations Systems combined have a billion dollar per year budget with NASA having pretty wide latitude with how it is spent(besides the portion of that budget that Congress directs to specific items). It is how they worked on ARM with Congress against it.
Purely FWIW, does the 2026 configuration of DSG remind anyone else of Skylab? Maybe they can call it 'Moonlab'? (Yes, I know, I know, my Steven Baxter amazing people is showing again!)
Thanks for the document.There are a few items that requires mention. This PPE will be the primary communications device for the DSG as long as it is attached to the other DSG elements. It also provides the battery power during solar array eclipses. So the other DSG elements would have very minimal batteries and communications. Unfortunately the weights and other capabilities for orbit maneuvers and RCS are TBD. There is no mention of a air lock or capability of moving through the two docking ports by personnel. So this document does not require that these ports be anything more than a place holder for other elements that provide for power, communications, and prop transfer but nothing more than a structural attach point. No crew egress. That makes a small problem with the Orion in that it cannot dock at the PPE and still do EVA or crew swap. This makes the supply procedures more complex for the DSG. Requiring the supply VV to dock at a crew access port first to be unloaded then undock and move to the PPE to transfer propellant. This would have to be done unless the other DSG elements all have additional piping and valves to be able to transfer prop through these other elements from the VV to the PPE.
Quote from: oldAtlas_Eguy on 08/18/2017 06:50 pm...( Is it counter to politeness here to use ellipsis to show text has been removed? - tdperk)I suspect that the DSG will be refuelled by unmanned cargo vehicles. Since the PPE's fuel tank can only take 2000 kg of propellant the Commercial Resupply Service DSG (CRS-DSG) can be performed in several ways. Most cheaper than Orion on SLS.
...( Is it counter to politeness here to use ellipsis to show text has been removed? - tdperk)
Quote from: A_M_Swallow on 08/19/2017 09:36 pmQuote from: oldAtlas_Eguy on 08/18/2017 06:50 pm...( Is it counter to politeness here to use ellipsis to show text has been removed? - tdperk)I suspect that the DSG will be refuelled by unmanned cargo vehicles. Since the PPE's fuel tank can only take 2000 kg of propellant the Commercial Resupply Service DSG (CRS-DSG) can be performed in several ways. Most cheaper than Orion on SLS.If NASA for some reason wants to continue avoiding necessary technology development, then instead of mastering bulk liquid fuel transfer in weightlessness, a propulsion module which docks to a DSG or other structure to maneuver it and undocks to permit a fresh one to attach should be developed. That propulsion module should include or be compatible with a return capability for refurbishment.
Quote from: tdperk on 08/20/2017 03:25 pmQuote from: A_M_Swallow on 08/19/2017 09:36 pmQuote from: oldAtlas_Eguy on 08/18/2017 06:50 pm...( Is it counter to politeness here to use ellipsis to show text has been removed? - tdperk)I suspect that the DSG will be refuelled by unmanned cargo vehicles. Since the PPE's fuel tank can only take 2000 kg of propellant the Commercial Resupply Service DSG (CRS-DSG) can be performed in several ways. Most cheaper than Orion on SLS.If NASA for some reason wants to continue avoiding necessary technology development, then instead of mastering bulk liquid fuel transfer in weightlessness, a propulsion module which docks to a DSG or other structure to maneuver it and undocks to permit a fresh one to attach should be developed. That propulsion module should include or be compatible with a return capability for refurbishment.Too complex, and easier to just ship 1-2mt of prop up with a regular commercial re-supply vehicle.
After the technology of bulk weightless liquid transfer is established it would be more complex, maybe.And I have had people tell me the reason SpaceX cannot possibly succeed with the ITS/BFT is that no one knows how to transfer liquids in bulk--so that's a showstopper. That we cannot count on that task being handled.
Quote from: tdperk on 08/21/2017 12:29 amAfter the technology of bulk weightless liquid transfer is established it would be more complex, maybe.And I have had people tell me the reason SpaceX cannot possibly succeed with the ITS/BFT is that no one knows how to transfer liquids in bulk--so that's a showstopper. That we cannot count on that task being handled. The technology is well established. They already do bulk propellant transfer for ISS.
Quote from: Propylox on 07/21/2017 03:09 am"Near rectilinear halo orbit" is a non-starter. [...] Dump the circus act for a useful LLO and the electric power and propulsion requirements evaporate, as does funding requirements.Is part of it about wanting a big SEP project in a post-ARM world? Back-solving from the tech they want to fund?
"Near rectilinear halo orbit" is a non-starter. [...] Dump the circus act for a useful LLO and the electric power and propulsion requirements evaporate, as does funding requirements.
Orion does not have enough propulsive capability to enter and return from LLO.