This chart strikes me as quite misleading.Longest coast, and time to separation, are indeed engineering challenges. But in no way is making a second stage that can coast for six hours six times harder than creating a stage that can coast for one hour. Likewise time to separation.Similarly, increasing the number of burns does not scale in difficulty with the number of burns required. Furthermore, it's not clear that one burn should be the baseline. According to usage, there should be an additional column at the left, labelled "leo with booster recovery". This should have 3 burns as the baseline. Then only the direct-injection missions are as hard; all the others are *easier* by that metric, requiring only one or two burns.
Quote from: meekGee on 07/05/2022 06:51 pmQuote from: DanClemmensen on 07/05/2022 06:35 pmQuote from: Robotbeat on 07/05/2022 06:26 pmDroneship landing is really enabling for Falcon 9 reuse. and I suspect Starship will eventually go in that direction over time, as will Neutron, Terran-R, etc. It’s just too much of a performance improvement to ignore, IMHO. (Although Super Heavy is currently optimized for RTLS, not downrange recovery, but if they stretch it some more, it’ll be more optimized for down-range landing.)Droneship is only useful when the payload mass exceeds the maximum that can be handled in an RTLS landing. There are currently no such payloads, so it's unclear that maintaining the whole Droneship support infrastructure is worthwhile. It's likely to be more cost-effect for those rare huge payloads to launch to a low orbit and then refuel the SS to reach the required orbit.Exactly. It's almost like SpaceX can dial-a-payload, if you know what I'm talking about.Starlink is the ultimate optimization exercise. They can load fewer and RTLS, but clearly the barge is cheap enough.But normal LEO satellites can get a cheaper launch if they can RTLS, and clearly that still works.You are describing F9 here, where droneships are optimal for certain payload masses. I was describing Starship, where I believe droneships will never be optimal for any payload mass. With F9, the only ways to increase max payload mass are droneship, expended booster, or Falcon Heavy, and launches all expend the second stage. With Starship, you can increase max payload mass by refuelling, or by expending either or both stages for really crazy and rare payloads that cannot be split. You can expend several SH per year for less money that maintaining a droneship infrastructure. By contrast with F9, dividing a payload between two launches is cheap, so aggregating payloads and then using a droneship makes no sense.
Quote from: DanClemmensen on 07/05/2022 06:35 pmQuote from: Robotbeat on 07/05/2022 06:26 pmDroneship landing is really enabling for Falcon 9 reuse. and I suspect Starship will eventually go in that direction over time, as will Neutron, Terran-R, etc. It’s just too much of a performance improvement to ignore, IMHO. (Although Super Heavy is currently optimized for RTLS, not downrange recovery, but if they stretch it some more, it’ll be more optimized for down-range landing.)Droneship is only useful when the payload mass exceeds the maximum that can be handled in an RTLS landing. There are currently no such payloads, so it's unclear that maintaining the whole Droneship support infrastructure is worthwhile. It's likely to be more cost-effect for those rare huge payloads to launch to a low orbit and then refuel the SS to reach the required orbit.Exactly. It's almost like SpaceX can dial-a-payload, if you know what I'm talking about.Starlink is the ultimate optimization exercise. They can load fewer and RTLS, but clearly the barge is cheap enough.But normal LEO satellites can get a cheaper launch if they can RTLS, and clearly that still works.
Quote from: Robotbeat on 07/05/2022 06:26 pmDroneship landing is really enabling for Falcon 9 reuse. and I suspect Starship will eventually go in that direction over time, as will Neutron, Terran-R, etc. It’s just too much of a performance improvement to ignore, IMHO. (Although Super Heavy is currently optimized for RTLS, not downrange recovery, but if they stretch it some more, it’ll be more optimized for down-range landing.)Droneship is only useful when the payload mass exceeds the maximum that can be handled in an RTLS landing. There are currently no such payloads, so it's unclear that maintaining the whole Droneship support infrastructure is worthwhile. It's likely to be more cost-effect for those rare huge payloads to launch to a low orbit and then refuel the SS to reach the required orbit.
Droneship landing is really enabling for Falcon 9 reuse. and I suspect Starship will eventually go in that direction over time, as will Neutron, Terran-R, etc. It’s just too much of a performance improvement to ignore, IMHO. (Although Super Heavy is currently optimized for RTLS, not downrange recovery, but if they stretch it some more, it’ll be more optimized for down-range landing.)
This chart strikes me as quite misleading.
Seems to me FH launched a payload to the vicinity of Mars, and Psyche also scheduled on a FH, which is commercial, not "USG" launcher.
What’s the use of a highly reusable rocket that can fly 1000 times if the reliability is only 95%, so it fails after just 20 launches?
Quote from: Robotbeat on 07/07/2022 12:58 pmWhat’s the use of a highly reusable rocket that can fly 1000 times if the reliability is only 95%, so it fails after just 20 launches?Not seeing the argument for this. Provided reusability doesn't increase the vehicle costs (both in per-unit manufacturing and per-flight refurbishment) by 20-fold, you are still saving money with reusability. (Obviously, low reliability on any vehicle reduces your market for payloads, but that isn't about reusability vs expendability, per se.)
Why is anyone even talking about 1000 flights/uses. Its the height of stupidity, that number is probably around the total number of orbital launches the US has ever done.
Quote from: deadman1204 on 07/27/2022 02:02 pmWhy is anyone even talking about 1000 flights/uses. Its the height of stupidity, that number is probably around the total number of orbital launches the US has ever done.Orbital rocket flight rate looks to be on an exponential growth curve. At least it does now that commercial rocket flights are the dominant driver.SX F9 already has more flights than any other commercial rocket. Communication constellations are providing the demand…why wouldn’t we expect the future to have thousands of flights?
Quote from: freddo411 on 07/27/2022 02:25 pmQuote from: deadman1204 on 07/27/2022 02:02 pmWhy is anyone even talking about 1000 flights/uses. Its the height of stupidity, that number is probably around the total number of orbital launches the US has ever done.Orbital rocket flight rate looks to be on an exponential growth curve. At least it does now that commercial rocket flights are the dominant driver.SX F9 already has more flights than any other commercial rocket. Communication constellations are providing the demand…why wouldn’t we expect the future to have thousands of flights?The current demand spurt is driven by Starlink. Possibly there will be one or two other constellations, but eventually the number of LEO comms satellites will saturate the market and/or will be regulated to stop the space junk chaos. At that point, actual build-out will cease and be replaced by a one-for-one upgrade strategy, replacing satellites with bigger newer satellites. I don't "see "thousands" of launches needed for this. Some new demand will need to evolve. If launch cost is radically lowered, maybe something like asteroid mining will become cost-effective.
Quote from: DanClemmensen on 07/27/2022 02:36 pmQuote from: freddo411 on 07/27/2022 02:25 pmQuote from: deadman1204 on 07/27/2022 02:02 pmWhy is anyone even talking about 1000 flights/uses. Its the height of stupidity, that number is probably around the total number of orbital launches the US has ever done.Orbital rocket flight rate looks to be on an exponential growth curve. At least it does now that commercial rocket flights are the dominant driver.SX F9 already has more flights than any other commercial rocket. Communication constellations are providing the demand…why wouldn’t we expect the future to have thousands of flights?The current demand spurt is driven by Starlink. Possibly there will be one or two other constellations, but eventually the number of LEO comms satellites will saturate the market and/or will be regulated to stop the space junk chaos. At that point, actual build-out will cease and be replaced by a one-for-one upgrade strategy, replacing satellites with bigger newer satellites. I don't "see "thousands" of launches needed for this. Some new demand will need to evolve. If launch cost is radically lowered, maybe something like asteroid mining will become cost-effective.It never saturates due to continuous replacement.
Quote from: deadman1204 on 07/27/2022 02:02 pmWhy is anyone even talking about 1000 flights/uses. Its the height of stupidity, that number is probably around the total number of orbital launches the US has ever done.The USA exceeded 1,000 total launches to orbit sometime around the year 2000. The USSR / Russia is near 3,000 total launches to orbit. The total for everyone else exceeded 1,000 fairly recently. The current global total for successful launches to orbit is approximately 5,500. The global average is approximately 80 launches per year, although there has been considerable variation. Everything I'm saying is approximate because I couldn't find any total numbers more recent than 2019, just charts.