Quote from: woods170 on 09/19/2022 12:51 pmQuote from: hektor on 09/19/2022 11:20 amAll the errors of Hermes, repeated 40 years later. The managers and system engineers of Hermes are still around, these guys should have talked to them.Sorry, but most of them are in fact no longer around. That is: a lot of them have retired or moved on to other businesses. And industries like Airbus et al. do not make a habit of asking the opinion of their retired engineers and managers before launching (pun intended) another bad idea.But I fully agree with you that SUSIE is repeating all the errors of Hermes. Starting with the unrealistic wet mass of just 25 metric tons for a vehicle that is 5 meters in diameter, is 12 meters long, has a crew compartment for 7 AND also having a 40 cubic meter payload bay AND a 7 metric ton payload capacity. That does not add up. Throw in a multi-ton propellant load and engines strong enough to land the entire thing propulsively and it does not add up AT ALL. Much like the numbers never added up for the initial 10 development iterations of Hermes. And when they finally DID start to add up for Hermes, the vehicle had lost most of its originally promised capabilities.If SUSIE remains marrried to a 25-ton-to-LEO launcher, than it will start losing capabilities and capacities fast, once they start to seriously develop this contraption.This book should be required reading for everyone who works in the European spaceflight industry: https://link.springer.com/book/10.1007/978-3-319-44472-7From my reading of the press release SUSIE would be either crew or cargo but not both, which makes it sound a lot like Dragon2. Also the press release said 5 crew not 7. The video showed a kick stage thus answering how a 25 t craft could be launched on Ariane 6. I am curious how SUSIE will do a propulsive landing, though.
Quote from: hektor on 09/19/2022 11:20 amAll the errors of Hermes, repeated 40 years later. The managers and system engineers of Hermes are still around, these guys should have talked to them.Sorry, but most of them are in fact no longer around. That is: a lot of them have retired or moved on to other businesses. And industries like Airbus et al. do not make a habit of asking the opinion of their retired engineers and managers before launching (pun intended) another bad idea.But I fully agree with you that SUSIE is repeating all the errors of Hermes. Starting with the unrealistic wet mass of just 25 metric tons for a vehicle that is 5 meters in diameter, is 12 meters long, has a crew compartment for 7 AND also having a 40 cubic meter payload bay AND a 7 metric ton payload capacity. That does not add up. Throw in a multi-ton propellant load and engines strong enough to land the entire thing propulsively and it does not add up AT ALL. Much like the numbers never added up for the initial 10 development iterations of Hermes. And when they finally DID start to add up for Hermes, the vehicle had lost most of its originally promised capabilities.If SUSIE remains marrried to a 25-ton-to-LEO launcher, than it will start losing capabilities and capacities fast, once they start to seriously develop this contraption.This book should be required reading for everyone who works in the European spaceflight industry: https://link.springer.com/book/10.1007/978-3-319-44472-7
All the errors of Hermes, repeated 40 years later. The managers and system engineers of Hermes are still around, these guys should have talked to them.
In addition, it may be a way for ArianeGroup to extend its' monopoly on launchers in Europe (again) since I suspect that there won't be an open competition to chart a way forward on european crewed vehicles (the discussion will be largely political, and probably occur already at the C-MIN22 in November).
Lots of taxpayer money will follow, likely without any benefit in cost of access to space unless explicitly forced by other ESA members (because Ariane 6 + Susie will still be a lot more expensive than the partially reusable Falcon9 + Dragon).
Europe cannot afford the kind of waste that NASA can, and this sure looks expensive. Let's see what the next steps are.
Quote from: Try_NBS on 09/19/2022 05:49 pmEffectively, if SUSIE is approved by minister's council, it will be in the same delays than Ariane NEXT. But I don't know if Ariane NEXT will be capable to launch a 25T spaceship. I have see on an Arianespace document the maximum payload will be about 20T.SUSIE has some of its own propulsion, right? It could do the circularization burn.
Effectively, if SUSIE is approved by minister's council, it will be in the same delays than Ariane NEXT. But I don't know if Ariane NEXT will be capable to launch a 25T spaceship. I have see on an Arianespace document the maximum payload will be about 20T.
From my reading of the press release SUSIE would be either crew or cargo but not both, which makes it sound a lot like Dragon2. Also the press release said 5 crew not 7.
The video showed a kick stage thus answering how a 25 t craft could be launched on Ariane 6. I am curious how SUSIE will do a propulsive landing, though.
Quote from: hektor on 09/19/2022 11:20 amAll the errors of Hermes, repeated 40 years later. The managers and system engineers of Hermes are still around, these guys should have talked to them.And Hermes was bascially modelled on the X20 Dyna-soar.Which also got cancelled due to unforseen weight growth (among a bunch of other reaasons, but it didn't help).You'll note the video give no idea of how this vehicle is going to re-enter the atmosphere. Since it has no wings it's closest resemblance is Crew Dragon, but with powered landing.
Quote from: beb on 09/19/2022 11:25 pmFrom my reading of the press release SUSIE would be either crew or cargo but not both, which makes it sound a lot like Dragon2. Also the press release said 5 crew not 7.Emphasis mine.Correct. That is my bad. I mixed up the numbers for crew and metric tons of cargo returned. Crew is five. Metric tons of cargo returned is seven.Thanks for pointing out.Quote from: beb on 09/19/2022 11:25 pmThe video showed a kick stage thus answering how a 25 t craft could be launched on Ariane 6. I am curious how SUSIE will do a propulsive landing, though. The video showed the Vinci-powered ULPM, which is not a kick stage but the standard upper stage of Ariane 6. The video also mentions that SUSIE would launch on Ariane 64 Evolution, which has a predicted payload-to-LEO capability of 25 metric tons.What I doubt (and so does Hektor if I read his posts correctly) is that the given capabilities of SUSIE, as presented in the video and press release, fit within the 25 metric ton wet mass limit. I think that they don't fit.
Quote from: Robotbeat on 09/19/2022 05:59 pmQuote from: Try_NBS on 09/19/2022 05:49 pmEffectively, if SUSIE is approved by minister's council, it will be in the same delays than Ariane NEXT. But I don't know if Ariane NEXT will be capable to launch a 25T spaceship. I have see on an Arianespace document the maximum payload will be about 20T.SUSIE has some of its own propulsion, right? It could do the circularization burn. Not if it also needs the same propulsion to do the deorbit burn AND land propulsively, all within a wet mass budget of max. 25 metric tons while having a crew cabin for 5 AND a 40 cubic meter payload bay with airlock for EVA AND other unpressurized cargo.The projected capabilities and the wet mass don't match. That is UNLESS the vehicle, after reaching orbit, goes to a propellant depot first. Needless to say: a propellant depot was not mentioned during the ArianeGroup presentation.So this thing, if considered for actual development, will be going down the same road as Hermes: once the engineers start adding up the numbers the mass will go up, which requires the capabilities and size going down to get the mass numbers back down to where they can meet the launch capabilities of the projected launch vehicle.
Quote from: woods170 on 09/20/2022 09:42 amQuote from: Robotbeat on 09/19/2022 05:59 pmQuote from: Try_NBS on 09/19/2022 05:49 pmEffectively, if SUSIE is approved by minister's council, it will be in the same delays than Ariane NEXT. But I don't know if Ariane NEXT will be capable to launch a 25T spaceship. I have see on an Arianespace document the maximum payload will be about 20T.SUSIE has some of its own propulsion, right? It could do the circularization burn. Not if it also needs the same propulsion to do the deorbit burn AND land propulsively, all within a wet mass budget of max. 25 metric tons while having a crew cabin for 5 AND a 40 cubic meter payload bay with airlock for EVA AND other unpressurized cargo.The projected capabilities and the wet mass don't match. That is UNLESS the vehicle, after reaching orbit, goes to a propellant depot first. Needless to say: a propellant depot was not mentioned during the ArianeGroup presentation.So this thing, if considered for actual development, will be going down the same road as Hermes: once the engineers start adding up the numbers the mass will go up, which requires the capabilities and size going down to get the mass numbers back down to where they can meet the launch capabilities of the projected launch vehicle.25t is the dry mass budget.
True, but it's not about cost, it's about guaranteed access, and there is a history of the US denying access to space launch when it's economic well being (or more accurately the well being of a US business) is threatened.
Quote from: woods170 on 09/20/2022 09:42 amQuote from: Robotbeat on 09/19/2022 05:59 pmQuote from: Try_NBS on 09/19/2022 05:49 pmEffectively, if SUSIE is approved by minister's council, it will be in the same delays than Ariane NEXT. But I don't know if Ariane NEXT will be capable to launch a 25T spaceship. I have see on an Arianespace document the maximum payload will be about 20T.SUSIE has some of its own propulsion, right? It could do the circularization burn. Not if it also needs the same propulsion to do the deorbit burn AND land propulsively, all within a wet mass budget of max. 25 metric tons while having a crew cabin for 5 AND a 40 cubic meter payload bay with airlock for EVA AND other unpressurized cargo.The projected capabilities and the wet mass don't match. That is UNLESS the vehicle, after reaching orbit, goes to a propellant depot first. Needless to say: a propellant depot was not mentioned during the ArianeGroup presentation.So this thing, if considered for actual development, will be going down the same road as Hermes: once the engineers start adding up the numbers the mass will go up, which requires the capabilities and size going down to get the mass numbers back down to where they can meet the launch capabilities of the projected launch vehicle.Unless they go directly to the Ariane NEXT...
Quote from: john smith 19 on 09/20/2022 08:15 amQuote from: hektor on 09/19/2022 11:20 amAll the errors of Hermes, repeated 40 years later. The managers and system engineers of Hermes are still around, these guys should have talked to them.And Hermes was bascially modelled on the X20 Dyna-soar.Which also got cancelled due to unforseen weight growth (among a bunch of other reaasons, but it didn't help).You'll note the video give no idea of how this vehicle is going to re-enter the atmosphere. Since it has no wings it's closest resemblance is Crew Dragon, but with powered landing. Emphasis mine.Think IXV and Space Rider: lifting body reentry.