I do not think that the DeltaV issue is quite as bad as you might think.
Maybe add some Superdracos in the trunk with some hypergolic fuel for return to earth.
Crew Dragon has an empty trunk. Why not use it for Super Dracos and some hypergolic fuel for the return flight.
What if Crew Dragon had an engine and small fuel tanks in the trunk of the service module?
Quote from: DanClemmensen on 11/29/2021 12:53 amQuote from: seb21051 on 11/28/2021 09:27 pmDon't know if this is the right place to ask this question, so please redirect if needed.I assume its feasible to send a Crew Dragon to the Gateway. Would it have to be with a FH or F9?<snip> I suspect you also need a new heat shield. At this point you have just re-invented Orion. Why bother? just send a crewed Starship.</snip>Dragon does not need a new heatshield. The current heatshield is already rated for lunar and Mars reentry into Earth's atmosphere.According to SpaceX; PICA-X, which is SpaceX's proprietary derivative of the PICA (Phenolic Impregnated Carbon Ablator) heatshield designed by NASA, can withstand reentries from "Lunar and Martian Velocities". Martian velocities being even higher, of course. PICA itself was used on the Stardust spacecraft which reentered at a speed of 46,500km/h. Apollo craft generally reentered at a speed of ~40,000km/h. An Earth reentry from Mars would, depending on how much energy you choose to expend, be between 49,000km/h-77,000km/h. Wired article.Another source is testimony that Garret Reisman himself offered, on page 4, where he says: Designed in partnership with NASA and fabricated by SpaceX, Crew Dragon’s heat shield is made of PICA-X, a high-performance improvement on NASA’s original phenolic impregnated carbon ablator (PICA). PICA-X is designed to withstand heat rates from a lunar return mission, which far exceed the requirements for a low Earth orbit mission.
Quote from: seb21051 on 11/28/2021 09:27 pmDon't know if this is the right place to ask this question, so please redirect if needed.I assume its feasible to send a Crew Dragon to the Gateway. Would it have to be with a FH or F9?<snip> I suspect you also need a new heat shield. At this point you have just re-invented Orion. Why bother? just send a crewed Starship.</snip>
Don't know if this is the right place to ask this question, so please redirect if needed.I assume its feasible to send a Crew Dragon to the Gateway. Would it have to be with a FH or F9?
Quote from: clongton on 11/29/2021 06:58 pmQuote from: DanClemmensen on 11/29/2021 12:53 amQuote from: seb21051 on 11/28/2021 09:27 pmDon't know if this is the right place to ask this question, so please redirect if needed.I assume its feasible to send a Crew Dragon to the Gateway. Would it have to be with a FH or F9?<snip> I suspect you also need a new heat shield. At this point you have just re-invented Orion. Why bother? just send a crewed Starship.</snip>Dragon does not need a new heatshield. The current heatshield is already rated for lunar and Mars reentry into Earth's atmosphere.According to SpaceX; PICA-X, which is SpaceX's proprietary derivative of the PICA (Phenolic Impregnated Carbon Ablator) heatshield designed by NASA, can withstand reentries from "Lunar and Martian Velocities". Martian velocities being even higher, of course. PICA itself was used on the Stardust spacecraft which reentered at a speed of 46,500km/h. Apollo craft generally reentered at a speed of ~40,000km/h. An Earth reentry from Mars would, depending on how much energy you choose to expend, be between 49,000km/h-77,000km/h. Wired article.Another source is testimony that Garret Reisman himself offered, on page 4, where he says: Designed in partnership with NASA and fabricated by SpaceX, Crew Dragon’s heat shield is made of PICA-X, a high-performance improvement on NASA’s original phenolic impregnated carbon ablator (PICA). PICA-X is designed to withstand heat rates from a lunar return mission, which far exceed the requirements for a low Earth orbit mission.Any ablative material can be made thick enough to withstand reentry from lunar / Mars return velocities. PICA-X isn't special in that regard, it has nothing to do with the material itself. Note: that prepared statement is from early 2015, at the time the Crew Dragon was not quite yet in a fully mature state of design. Propulsive landing was still in play at that point, and it still had the movable ballast sled, both of which were discussed in the statement. A much more recent statement from Garret Reismann for a 2020 arstechnica article says that the heatshield would require some modification (i.e., being made thicker) to handle a lunar return. "Crew Dragon was designed for low Earth orbit ... traveling beyond low Earth orbit would therefore require some substantial but feasible changes to the spacecraft, Reismann said. Dragon’s communication system works through GPS, so it would need a new communications and navigation system. In terms of radiation, he said, addressing this for astronauts is relatively straightforward, but hardening electronics would require some work. The heat shield could be made capable of returning from the Moon relatively easily, Reismann said. Additional consumables for a longer journey would take up interior volume."https://arstechnica.com/science/2020/08/could-a-dragon-spacecraft-fly-humans-to-the-moon-its-complicated/
With all of the projects that SpaceX has going on this one seems to produce zero news.Is it a low level project at this point or is SpaceX just keeping it quiet.I would expect some information through NASA reporting and design requirements.Thanks for humoring me.
Quote from: wannamoonbase on 03/08/2022 03:47 pmWith all of the projects that SpaceX has going on this one seems to produce zero news.Is it a low level project at this point or is SpaceX just keeping it quiet.I would expect some information through NASA reporting and design requirements.Thanks for humoring me.We don't seem to be hearing much about Lunar Gateway at all, much less Dragon XL. Gateway is now considered optional for Artemis III and will not even get its third module, I-HAB, until Artemis IV. I don't know when it will need its first Dragon XL supply mission, but I think it must surely be after 2026.Speculation: although Starship HLS is not intended for Gateway logistics, It is probably capable of it, and a variant would clearly be capable of it. It would be less expensive per mission even if non-reusable, with of course massively increased capacity. The smart thing to do would be cancel Dragon XL in favor of Starship GLS. The smarter thing to do would be cancel Gateway.
Two years ago this month, I opined in this thread that hopefully SpaceX won't actually have to build Dragon XL, if NASA uses Starship as part of Artemis, they'll inevitably harmonize their roadmap with SpaceX, and Dragon XL will fall by the wayside. Subsequently, NASA admitted that maximum mass limit in the Gateway Logistics requirements, which excluded the possibility of bidding Starship, was unnecessary in hindsight. This was a botched procurement, and neither party wants to sink any money into it. NASA isn't going to need this. Commercial customers aren't going to need this. Nobody is going to need this, and there's no reason to build it.
Quote from: butters on 03/08/2022 06:01 pmTwo years ago this month, I opined in this thread that hopefully SpaceX won't actually have to build Dragon XL, if NASA uses Starship as part of Artemis, they'll inevitably harmonize their roadmap with SpaceX, and Dragon XL will fall by the wayside. Subsequently, NASA admitted that maximum mass limit in the Gateway Logistics requirements, which excluded the possibility of bidding Starship, was unnecessary in hindsight. This was a botched procurement, and neither party wants to sink any money into it. NASA isn't going to need this. Commercial customers aren't going to need this. Nobody is going to need this, and there's no reason to build it.Axiom could use it out fit their station.
Quote from: Tomness on 03/08/2022 06:03 pmQuote from: butters on 03/08/2022 06:01 pmTwo years ago this month, I opined in this thread that hopefully SpaceX won't actually have to build Dragon XL, if NASA uses Starship as part of Artemis, they'll inevitably harmonize their roadmap with SpaceX, and Dragon XL will fall by the wayside. Subsequently, NASA admitted that maximum mass limit in the Gateway Logistics requirements, which excluded the possibility of bidding Starship, was unnecessary in hindsight. This was a botched procurement, and neither party wants to sink any money into it. NASA isn't going to need this. Commercial customers aren't going to need this. Nobody is going to need this, and there's no reason to build it.Axiom could use it out fit their station.It's expendable and requires FH and would therefore be $$$ compared to standard Cargo Dragon 2.
Quote from: pages 5 and 6 of the MOUArticle 5. Gateway Elements5.5 The Gateway is comprised of the following elements, although the Parties recognize these are subject to change in the course of the detailed design, development, and operation of the Gateway. The Parties intend for an up-to-date listing of all of the Gateway's elements to be maintained in accordance with Article 8 (Management).(a) NASA:1. Power and Propulsion2. Habitation Capability3. Avionics and Communications Infrastructure4. Logistics Resupply5. Crew Transportation6. Extravehicular Activity (EVA) System(b) CSA:1. External Robotic Capability2. External Robotics Interfaces3. End-to-End External Robotic Operations(c) ESA:1. Habitation Capability (I-Hab)2. Enhanced Lunar Communications3. Refueling and Viewing Capability4. European Service Modules in support of Orion missions(d) The GOJ [Japan]:1. Habitation Capability Infrastructure Functions2. Logistics Resupply(e) ROSCOSMOS:1. Crew AirlockArticle 6. Major Program Milestones6.1 Major target milestones are as follows:(a) 2023 — Delivery of the first Gateway element, power and propulsion, to lunar orbit(b) 2023 — Delivery of the initial habitation capability with enhanced lunar communications to the Gateway(c) 2024 — Gateway ready for the first crewed mission(d) 2025 — Delivery of additional habitation capability to the Gateway (I-Hab)(e) 2026 — Delivery of external robotic capability to the Gateway(f) 2027 — Delivery of refueling and viewing element to the Gateway(g) 2028 — Delivery of the crew airlock to the Gatewayhttps://t.co/gsyzWQBwr2?amp=1
Article 5. Gateway Elements5.5 The Gateway is comprised of the following elements, although the Parties recognize these are subject to change in the course of the detailed design, development, and operation of the Gateway. The Parties intend for an up-to-date listing of all of the Gateway's elements to be maintained in accordance with Article 8 (Management).(a) NASA:1. Power and Propulsion2. Habitation Capability3. Avionics and Communications Infrastructure4. Logistics Resupply5. Crew Transportation6. Extravehicular Activity (EVA) System(b) CSA:1. External Robotic Capability2. External Robotics Interfaces3. End-to-End External Robotic Operations(c) ESA:1. Habitation Capability (I-Hab)2. Enhanced Lunar Communications3. Refueling and Viewing Capability4. European Service Modules in support of Orion missions(d) The GOJ [Japan]:1. Habitation Capability Infrastructure Functions2. Logistics Resupply(e) ROSCOSMOS:1. Crew AirlockArticle 6. Major Program Milestones6.1 Major target milestones are as follows:(a) 2023 — Delivery of the first Gateway element, power and propulsion, to lunar orbit(b) 2023 — Delivery of the initial habitation capability with enhanced lunar communications to the Gateway(c) 2024 — Gateway ready for the first crewed mission(d) 2025 — Delivery of additional habitation capability to the Gateway (I-Hab)(e) 2026 — Delivery of external robotic capability to the Gateway(f) 2027 — Delivery of refueling and viewing element to the Gateway(g) 2028 — Delivery of the crew airlock to the Gateway
Quote from: yg1968 on 11/30/2020 03:44 pmQuote from: pages 5 and 6 of the MOUArticle 5. Gateway Elements5.5 The Gateway is comprised of the following elements, although the Parties recognize these are subject to change in the course of the detailed design, development, and operation of the Gateway. The Parties intend for an up-to-date listing of all of the Gateway's elements to be maintained in accordance with Article 8 (Management).(a) NASA:1. Power and Propulsion2. Habitation Capability3. Avionics and Communications Infrastructure4. Logistics Resupply5. Crew Transportation6. Extravehicular Activity (EVA) System(b) CSA:1. External Robotic Capability2. External Robotics Interfaces3. End-to-End External Robotic Operations(c) ESA:1. Habitation Capability (I-Hab)2. Enhanced Lunar Communications3. Refueling and Viewing Capability4. European Service Modules in support of Orion missions(d) The GOJ [Japan]:1. Habitation Capability Infrastructure Functions2. Logistics Resupply(e) ROSCOSMOS:1. Crew AirlockArticle 6. Major Program Milestones6.1 Major target milestones are as follows:(a) 2023 — Delivery of the first Gateway element, power and propulsion, to lunar orbit(b) 2023 — Delivery of the initial habitation capability with enhanced lunar communications to the Gateway(c) 2024 — Gateway ready for the first crewed mission(d) 2025 — Delivery of additional habitation capability to the Gateway (I-Hab)(e) 2026 — Delivery of external robotic capability to the Gateway(f) 2027 — Delivery of refueling and viewing element to the Gateway(g) 2028 — Delivery of the crew airlock to the Gatewayhttps://t.co/gsyzWQBwr2?amp=1See the timeline above. You can essentially add a year to all of these dates. I think that the first Dragon XL and the I-Hab are part of the Artemis IV mission. The second Dragon XL would be used to bring the external robotic capability to Gateway.
The smart thing to do would be cancel Dragon XL in favor of Starship GLS. The smarter thing to do would be cancel Gateway.
Quote from: DanClemmensen on 03/08/2022 04:14 pmThe smart thing to do would be cancel Dragon XL in favor of Starship GLS. The smarter thing to do would be cancel Gateway.Unwise. I wouldn't even consider considering Starship until it flies to at least LEO and successfully returns to the launch site - several times. Once it has consistently demonstrated that it will actually live up to all the hype, then maybe. All of us have the highest expectations for Starship but as of now it is not a viable option. It has only made low level hops using engines that will not even be on the operational vehicle and the booster has never flown at all. Don't let your enthusiasm get ahead of reality.