My guess is that the S2 and DXL will be inserted in a somewhat eccentric orbit, simply because it doesn't need to be circular. The S2 will then coast to perigee and provide all of the delta-v to TLI. The DXL will then separate, and the Dracos will provide the delta-v necessary to insert into NRHO via a lunar flyby, as well as whatever is needed for rendezvous and docking. It comes out to about 450 m/s.If we assume a 6 t DXL with 3 t of MMH/NTO for the Dracos, I get the following max payloads to TLI, using the remaining prop from the S2:FHE: 9.2 tFH2R: 6.5 tFH3R: 1.0 t
Quote from: dgmckenzie on 03/28/2020 11:37 amIf it is supposed to transfer both pressurized and unpressurized cargo, how could it have docking at both ends?It would need a different variant. But I think putting a docking tunnel through the propulsion section is the harder part, which is already done as part of the basic design.
If it is supposed to transfer both pressurized and unpressurized cargo, how could it have docking at both ends?
Quote from: Cherokee43v6 on 03/29/2020 12:20 amThis brings up a question I've wondered about a bit.This is cargo. It's not necessarily 'speed sensitive' on delivery. Therefore, would it not be a reasonable consideration to increase cargo mass by going with a different proven thruster technology. Say an Ion Thruster something like DS-1 used? Trading fuel mass for cargo mass? So it takes weeks instead of days to arrive. Again, it's not necessarily time critical on the delivery.Back when NASA still had the HLS option analysis up (I saved a copy of it here, p. 27), they addressed the topic of why they had ruled out SEP for 15 t payloads:Quote• A SEP Tug comparable to Gateway PPE would have a minimum Time-of-Flight (ToF)greater than 420 days to deliver a 15 t HLS element from GTO to NRHO(300+ days of spiral time GTO-TLI; 120 day ballistic transfer TLI-NRHO).• This transfer time is more than 20% of the remaining schedule for HLS and it was judgedto be an impractical approach for achieving the 2024 mission timeline.As always, to use SEP effectively, you either need tiny payloads or you have to be really, really sure of your schedule.
This brings up a question I've wondered about a bit.This is cargo. It's not necessarily 'speed sensitive' on delivery. Therefore, would it not be a reasonable consideration to increase cargo mass by going with a different proven thruster technology. Say an Ion Thruster something like DS-1 used? Trading fuel mass for cargo mass? So it takes weeks instead of days to arrive. Again, it's not necessarily time critical on the delivery.
• A SEP Tug comparable to Gateway PPE would have a minimum Time-of-Flight (ToF)greater than 420 days to deliver a 15 t HLS element from GTO to NRHO(300+ days of spiral time GTO-TLI; 120 day ballistic transfer TLI-NRHO).• This transfer time is more than 20% of the remaining schedule for HLS and it was judgedto be an impractical approach for achieving the 2024 mission timeline.
Quote from: Robotbeat on 03/28/2020 12:53 pmQuote from: dgmckenzie on 03/28/2020 11:37 amIf it is supposed to transfer both pressurized and unpressurized cargo, how could it have docking at both ends?It would need a different variant. But I think putting a docking tunnel through the propulsion section is the harder part, which is already done as part of the basic design.Naive question: why not laterally?This could solve propulsion/unpressurized issue, and enable much more configurations, expecially with double lateral docking ports.I'm vaguely aware it will require reinforced structure and a lot of complex stuff.
Quote from: TheRadicalModerate on 03/29/2020 05:02 amQuote from: Cherokee43v6 on 03/29/2020 12:20 amThis brings up a question I've wondered about a bit.This is cargo. It's not necessarily 'speed sensitive' on delivery. Therefore, would it not be a reasonable consideration to increase cargo mass by going with a different proven thruster technology. Say an Ion Thruster something like DS-1 used? Trading fuel mass for cargo mass? So it takes weeks instead of days to arrive. Again, it's not necessarily time critical on the delivery.Back when NASA still had the HLS option analysis up (I saved a copy of it here, p. 27), they addressed the topic of why they had ruled out SEP for 15 t payloads:Quote• A SEP Tug comparable to Gateway PPE would have a minimum Time-of-Flight (ToF)greater than 420 days to deliver a 15 t HLS element from GTO to NRHO(300+ days of spiral time GTO-TLI; 120 day ballistic transfer TLI-NRHO).• This transfer time is more than 20% of the remaining schedule for HLS and it was judgedto be an impractical approach for achieving the 2024 mission timeline.As always, to use SEP effectively, you either need tiny payloads or you have to be really, really sure of your schedule.Thank you. I was aware SEP was slower, but not THAT much slower!
Does anyone have a good estimate for Falcon Heavy near-escape capability for core-expendable and booster down-range recovery mode? Such a mode does not yet exist, of course, because SpaceX hasn't demonstrated dual downrange recovery. I know about Elon's 10% payload reduction estimate, but he never said if that was for LEO or GTO, etc. My guess is 10% for LEO, but a bigger reduction for higher energy orbits. My estimate for 5 tonnes cargo to Near Rectilinear Halo (lunar) Orbit (NRHO) is that 12 to 16 tonnes (payload, spacecraft, propellant) would need to separate into TLI, providing 10.5 to 13.8 tonnes to NRHO (13.5% of mass used for the burns to NRHO). The three-core recovery mode for Falcon Heavy only provides 8 tonnes to GTO, while fully expendable Falcon Heavy is listed at 26.7 tonnes GTO or 16.8 tonnes trans-Mars. - Ed Kyle
Quote from: edkyle99 on 03/29/2020 03:20 pmDoes anyone have a good estimate for Falcon Heavy near-escape capability for core-expendable and booster down-range recovery mode? Such a mode does not yet exist, of course, because SpaceX hasn't demonstrated dual downrange recovery. I know about Elon's 10% payload reduction estimate, but he never said if that was for LEO or GTO, etc. My guess is 10% for LEO, but a bigger reduction for higher energy orbits. My estimate for 5 tonnes cargo to Near Rectilinear Halo (lunar) Orbit (NRHO) is that 12 to 16 tonnes (payload, spacecraft, propellant) would need to separate into TLI, providing 10.5 to 13.8 tonnes to NRHO (13.5% of mass used for the burns to NRHO). The three-core recovery mode for Falcon Heavy only provides 8 tonnes to GTO, while fully expendable Falcon Heavy is listed at 26.7 tonnes GTO or 16.8 tonnes trans-Mars. - Ed KyleCitation needed for just 8 tons GTO with 3 booster recovery. I think the assumptions for that are much more conservative (sandbagged) than those for the 16.8tonnes TMI estimate.Also, center core expended and 2 cores RTLS is a thing.
Quote from: Karloss12 on 03/28/2020 11:02 pmEven though the hardware is largely derived from legacy equipment, the Earth-Lunar transfer and docking technology will be an important boost for SpaceX experience.And SpaceX will be making an absolute packet in profit margins for each mission as they know that they are only competing with the astronomically priced Delta IV Heavy.This is going to be a much celebrated mission for SpaceX. They will pocket a lot of cash and also develop themselves a new technology.My boldingCan you site evidence of anyone making a killing on a NASA contract?Even Boeing isn't "cleaning up" on SLS. They are just getting fixed or award fees for the last decade, and that's good enough.The company I work for has done a many instruments and missions for NASA. It's a good business. Higher margin than the commodity stuff. But it doesn't bloat the bottom line.A big issue for SpaceX is that this is seems to be a fixed price contract, IDIQ, for a system involved with astronauts, and at any time NASA can increase the requirements. SpaceX has experience with this, and probably didn't underbid the competition by $1.6B again. But it remains a risk, not a bonanza.
Even though the hardware is largely derived from legacy equipment, the Earth-Lunar transfer and docking technology will be an important boost for SpaceX experience.And SpaceX will be making an absolute packet in profit margins for each mission as they know that they are only competing with the astronomically priced Delta IV Heavy.This is going to be a much celebrated mission for SpaceX. They will pocket a lot of cash and also develop themselves a new technology.
Quote from: Comga on 03/28/2020 11:22 pmQuote from: Karloss12 on 03/28/2020 11:02 pmEven though the hardware is largely derived from legacy equipment, the Earth-Lunar transfer and docking technology will be an important boost for SpaceX experience.And SpaceX will be making an absolute packet in profit margins for each mission as they know that they are only competing with the astronomically priced Delta IV Heavy.This is going to be a much celebrated mission for SpaceX. They will pocket a lot of cash and also develop themselves a new technology.My boldingCan you site evidence of anyone making a killing on a NASA contract?Even Boeing isn't "cleaning up" on SLS. They are just getting fixed or award fees for the last decade, and that's good enough.The company I work for has done a many instruments and missions for NASA. It's a good business. Higher margin than the commodity stuff. But it doesn't bloat the bottom line.A big issue for SpaceX is that this is seems to be a fixed price contract, IDIQ, for a system involved with astronauts, and at any time NASA can increase the requirements. SpaceX has experience with this, and probably didn't underbid the competition by $1.6B again. But it remains a risk, not a bonanza.I site the laws of capitalism. In particular, competition.The FH costs about $120mil. The Delta IV is $400mil.SpaceX will have bid around $350mil and be making a packet. Good on them. They need the cash to fund R&D.
I site(sp) the laws of capitalism. In particular, competition.The FH costs about $120mil. The Delta IV is $400mil.SpaceX will have bid around $350mil and be making a packet. Good on them. They need the cash to fund R&D.
I site the laws of capitalism. In particular, competition.The FH costs about $120mil. The Delta IV is $400mil.
SpaceX will have bid around $350mil and be making a packet. Good on them. They need the cash to fund R&D.
I think you may be heavy on your empty DXL weight...I'm currently assuming ~4 t DXL with ~5 t of MMH/NTO and spec 5 t payload...FH Boosters to ASDS's (try anyway) and Core will be expended (no choice)... Fairing catch attempted also...S2 burns twice... Once to initial and once Oberth... releases DXL on 2nd outbound leg...S2 saves enough to burp once more at top of arc and then burns up on next earth inbound pass...DXL first burn is just enough to get away from S2 and lengthen it's outbound arc just a bit...Swings around and does several Oberth thruster passes to lengthen the arc till it reaches moon capture.Does its job... has enough prop still left to, with careful planning, end up burning up in earths atmosphere...See... I'm figuring up to 2 weeks to get there and maybe a month getting back...There is no real hurry... no souls aboard... Just stuff and latter trash... This is not Apollo 2.0... this is an unmanned space truck doing a job 50 years later.JMHO... JAOn edit...I hope like heck SpaceX puts some good cameras on DXL and runs a near 24/7 YouTube feed while this thing does its job...That would be epic, and great PR for them AND for space in general...
PPE is more powerful than shown in that slide, which would cut off a good portion of a year from the time estimate. Also those numbers are for a much larger payload than what Dragon XL will be carrying. The slide is for a SEP tug plus a 15t payload.
Government procurement guidelines don't allow for predatory pricing, and SpaceX is not known for predatory pricing, so if NASA required the fully capabilities of a Falcon Heavy they would pay $150M for the basic launch service. And if they needed more than the basic launch service, which they normally do, then that would be an added cost, but the basic launch service cost does not change.
Quote from: Karloss12 on 03/29/2020 07:15 pmI site the laws of capitalism. In particular, competition.The FH costs about $120mil. The Delta IV is $400mil.Elon Musk said a fully expendable Falcon Heavy would be $150M.https://twitter.com/elonmusk/status/963076231921938432?ref_src=twsrc%5Etfw%7Ctwcamp%5Etweetembed&ref_url=https%3A%2F%2Fwww.cnbc.com%2F2018%2F02%2F12%2Felon-musk-spacex-falcon-heavy-costs-150-million-at-most.htmlQuoteSpaceX will have bid around $350mil and be making a packet. Good on them. They need the cash to fund R&D.Government procurement guidelines don't allow for predatory pricing, and SpaceX is not known for predatory pricing, so if NASA required the fully capabilities of a Falcon Heavy they would pay $150M for the basic launch service. And if they needed more than the basic launch service, which they normally do, then that would be an added cost, but the basic launch service cost does not change.
Quote from: Coastal Ron on 03/29/2020 07:57 pmGovernment procurement guidelines don't allow for predatory pricing, and SpaceX is not known for predatory pricing, so if NASA required the fully capabilities of a Falcon Heavy they would pay $150M for the basic launch service. And if they needed more than the basic launch service, which they normally do, then that would be an added cost, but the basic launch service cost does not change.Agree with the basic launch cost figure, but I would assume that SpaceX would add some appropriate premium - agreed to by NASA - based on a 5-launch demonstrated capability for the vehicles they will now no longer be able to reuse.
Quote from: Coastal Ron on 03/29/2020 07:57 pmGovernment procurement guidelines don't allow for predatory pricing, and SpaceX is not known for predatory pricing, so if NASA required the fully capabilities of a Falcon Heavy they would pay $150M for the basic launch service. And if they needed more than the basic launch service, which they normally do, then that would be an added cost, but the basic launch service cost does not change.True, but there is a surcharge on top of the $150M for the additional insight, documentation and processing controls that NASA insists on for missions of this type (see price differential between F9 launches for commercial vs F9 launches for NASA and USAF (soon to be USSF) missions).
Quote from: Robotbeat on 03/29/2020 03:40 pmQuote from: edkyle99 on 03/29/2020 03:20 pmDoes anyone have a good estimate for Falcon Heavy near-escape capability for core-expendable and booster down-range recovery mode? Such a mode does not yet exist, of course, because SpaceX hasn't demonstrated dual downrange recovery. I know about Elon's 10% payload reduction estimate, but he never said if that was for LEO or GTO, etc. My guess is 10% for LEO, but a bigger reduction for higher energy orbits. My estimate for 5 tonnes cargo to Near Rectilinear Halo (lunar) Orbit (NRHO) is that 12 to 16 tonnes (payload, spacecraft, propellant) would need to separate into TLI, providing 10.5 to 13.8 tonnes to NRHO (13.5% of mass used for the burns to NRHO). The three-core recovery mode for Falcon Heavy only provides 8 tonnes to GTO, while fully expendable Falcon Heavy is listed at 26.7 tonnes GTO or 16.8 tonnes trans-Mars. - Ed KyleCitation needed for just 8 tons GTO with 3 booster recovery. I think the assumptions for that are much more conservative (sandbagged) than those for the 16.8tonnes TMI estimate.Also, center core expended and 2 cores RTLS is a thing.I think that comes directly from SpaceX:https://www.spacex.com/about/capabilities
