Quote from: lrk on 04/12/2019 04:44 pmIf the reason they are shutting down engines is to limit G-loading, wouldn't it make more sense to shut down engines on the center core than on the boosters? This would allow them to burn more propellant on the side boosters than the center core, and would slightly improve payload. 3 of the center core engines are restartable, any engines that were shut down could be re-lit after staging. They can only relight the engines as long as they still have TEA-TEB in the tanks. The center core on the first FH launch failed to land because it ran out of it during the landing burn startup so I guess the margins are already pretty tight.
If the reason they are shutting down engines is to limit G-loading, wouldn't it make more sense to shut down engines on the center core than on the boosters? This would allow them to burn more propellant on the side boosters than the center core, and would slightly improve payload. 3 of the center core engines are restartable, any engines that were shut down could be re-lit after staging.
ISTM that the "toastiness" of a given stage should be able to be managed by the duration of the re-entry burn (assuming you have the propellant to burn). If that's the case, then where do the comments about variable levels of "toastiness" come from?
Keep in mind that the boosters will always get toasted a bit by the center core during separation, that can't be avoided. But I'm not sure much much that contributes to the final "toastiness".
It seems to me that the peak velocity of the boosters in space is irrelevant to the velocity of the boosters after they complete their individual re-entry burns.
49er,I think I have understood that the 'sootiness' is not soot, it is scorching from re-entry heat. (They don't wash off the soot because it isn't soot.) So I believe blacker look is caused by re-entry heat.
Good to see all three booster cores down safely and to hear that the fairings are down intact and in reusable condition.If nothing else, Elon Musk can rightfully claim to have changed the face of rocketry. What was previously considered to be so high-concept that only NASA or some other state space agency could possibly attempt it has been achieved by SpaceX instead: Mostly-reusable launch vehicles with loss of hardware pulled down to a bare minimum.The paradigm has changed; ULA, Arianespace and all the other developers and manufactures of launch vehicles now have to accept and follow the path SpaceX and Blue Origin are treading. Any launch vehicle that does not include reusable boosters is going to have a hard time surviving the bean-counters' scrutiny.
It's actually a bit of both. Note how they cleaned/polished up the first reused booster quite a bit. (BulgariaSat 1, see image) It was not repainted. So most of it just soot.For later launches they decided that deep level of cleaning was not needed.
Quote from: Ben the Space Brit on 04/12/2019 10:03 amGood to see all three booster cores down safely and to hear that the fairings are down intact and in reusable condition.If nothing else, Elon Musk can rightfully claim to have changed the face of rocketry. What was previously considered to be so high-concept that only NASA or some other state space agency could possibly attempt it has been achieved by SpaceX instead: Mostly-reusable launch vehicles with loss of hardware pulled down to a bare minimum.The paradigm has changed; ULA, Arianespace and all the other developers and manufactures of launch vehicles now have to accept and follow the path SpaceX and Blue Origin are treading. Any launch vehicle that does not include reusable boosters is going to have a hard time surviving the bean-counters' scrutiny.I am amazed and appalled that SpaceX has never been awarded the Collier Trophy (basically the Nobel Prize for aerospace engineering). As I understand it, they haven’t even been a finalist since the last Falcon 1 flight. I think Falcon Heavy alone deserves it; if they fly two FH missions this year and fly crew to ISS, they better win it for 2019!
Quote from: obi-wan on 04/12/2019 07:21 pmQuote from: Ben the Space Brit on 04/12/2019 10:03 amGood to see all three booster cores down safely and to hear that the fairings are down intact and in reusable condition.If nothing else, Elon Musk can rightfully claim to have changed the face of rocketry. What was previously considered to be so high-concept that only NASA or some other state space agency could possibly attempt it has been achieved by SpaceX instead: Mostly-reusable launch vehicles with loss of hardware pulled down to a bare minimum.The paradigm has changed; ULA, Arianespace and all the other developers and manufactures of launch vehicles now have to accept and follow the path SpaceX and Blue Origin are treading. Any launch vehicle that does not include reusable boosters is going to have a hard time surviving the bean-counters' scrutiny.I am amazed and appalled that SpaceX has never been awarded the Collier Trophy (basically the Nobel Prize for aerospace engineering). As I understand it, they haven’t even been a finalist since the last Falcon 1 flight. I think Falcon Heavy alone deserves it; if they fly two FH missions this year and fly crew to ISS, they better win it for 2019!Other aerospace achievements overshadowed SpaceX (Blue Origin won for the first booster landing). If it flies crew first, then it should get a very strong nomination for flying crew on the Dragon.
Quote from: Lars-J on 04/12/2019 07:18 pmIt's actually a bit of both. Note how they cleaned/polished up the first reused booster quite a bit. (BulgariaSat 1, see image) It was not repainted. So most of it just soot.For later launches they decided that deep level of cleaning was not needed.Hmm, perhaps that serves me right for believing Musk.Are you saying Musk is lying / being misleading?
Quote from: whitelancer64 on 04/12/2019 08:01 pmQuote from: obi-wan on 04/12/2019 07:21 pmQuote from: Ben the Space Brit on 04/12/2019 10:03 amGood to see all three booster cores down safely and to hear that the fairings are down intact and in reusable condition.If nothing else, Elon Musk can rightfully claim to have changed the face of rocketry. What was previously considered to be so high-concept that only NASA or some other state space agency could possibly attempt it has been achieved by SpaceX instead: Mostly-reusable launch vehicles with loss of hardware pulled down to a bare minimum.The paradigm has changed; ULA, Arianespace and all the other developers and manufactures of launch vehicles now have to accept and follow the path SpaceX and Blue Origin are treading. Any launch vehicle that does not include reusable boosters is going to have a hard time surviving the bean-counters' scrutiny.I am amazed and appalled that SpaceX has never been awarded the Collier Trophy (basically the Nobel Prize for aerospace engineering). As I understand it, they haven’t even been a finalist since the last Falcon 1 flight. I think Falcon Heavy alone deserves it; if they fly two FH missions this year and fly crew to ISS, they better win it for 2019!Other aerospace achievements overshadowed SpaceX (Blue Origin won for the first booster landing). If it flies crew first, then it should get a very strong nomination for flying crew on the Dragon.What achievements exactly? Also that was the DC-X...
Blue Origin won in 2016 “for successfully demonstrating rocket booster reusability with the New Shepard human spaceflight vehicle through five successful test flights of a single booster and engine, all of which performed powered vertical landings on Earth,” per the statement from the National Aeronautic Association. DC-XA only flew to a maximum of 10,300 ft.
Quote from: whitelancer64 on 04/12/2019 08:43 pmBlue Origin won in 2016 “for successfully demonstrating rocket booster reusability with the New Shepard human spaceflight vehicle through five successful test flights of a single booster and engine, all of which performed powered vertical landings on Earth,” per the statement from the National Aeronautic Association. DC-XA only flew to a maximum of 10,300 ft.New Shepherd is the Boeing 247 to Falcon 9's DC-3. Not sure what that makes the DC-X.
Quote from: envy887 on 04/12/2019 02:33 pmQuote from: edkyle99 on 04/12/2019 02:07 pmTerrific launch for SpaceX, and at a key moment with NSSL and NASA's SLS frustration underway. I have only one note about the news coverage. Repeatedly, it is written that Falcon Heavy is "the world’s most powerful operational launcher", etc., which technically is true in terms of liftoff thrust, but FH-2 only put 6,465 kg into GEO-1500-ish m/s. That's only 64% or so of what Ariane 5 ECA has boosted to an equivalent orbit. All of that thrust is neat, but much of it is not being used for the actual payload mission. - Ed KylePower isn't a good metric for measuring payload capacity. But FH can easily beat A5 ECA on either.It could, in expendable mode, but SpaceX doesn't seem to be planning to use it that way. I'm not sure it would cost less than an Ariane 5 if flown expendably. - Ed Kyle
Quote from: edkyle99 on 04/12/2019 02:07 pmTerrific launch for SpaceX, and at a key moment with NSSL and NASA's SLS frustration underway. I have only one note about the news coverage. Repeatedly, it is written that Falcon Heavy is "the world’s most powerful operational launcher", etc., which technically is true in terms of liftoff thrust, but FH-2 only put 6,465 kg into GEO-1500-ish m/s. That's only 64% or so of what Ariane 5 ECA has boosted to an equivalent orbit. All of that thrust is neat, but much of it is not being used for the actual payload mission. - Ed KylePower isn't a good metric for measuring payload capacity. But FH can easily beat A5 ECA on either.
Terrific launch for SpaceX, and at a key moment with NSSL and NASA's SLS frustration underway. I have only one note about the news coverage. Repeatedly, it is written that Falcon Heavy is "the world’s most powerful operational launcher", etc., which technically is true in terms of liftoff thrust, but FH-2 only put 6,465 kg into GEO-1500-ish m/s. That's only 64% or so of what Ariane 5 ECA has boosted to an equivalent orbit. All of that thrust is neat, but much of it is not being used for the actual payload mission. - Ed Kyle
Quote from: mn on 04/12/2019 02:17 pmQuote from: edkyle99 on 04/12/2019 02:07 pmTerrific launch for SpaceX, and at a key moment with NSSL and NASA's SLS frustration underway. I have only one note about the news coverage. Repeatedly, it is written that Falcon Heavy is "the world’s most powerful operational launcher", etc., which technically is true in terms of liftoff thrust, but FH-2 only put 6,465 kg into GEO-1500-ish m/s. That's only 64% or so of what Ariane 5 ECA has boosted to an equivalent orbit. All of that thrust is neat, but much of it is not being used for the actual payload mission. - Ed KyleIf you expended all 3 cores, (and enlarged the fairing, strengthened the payload adapter) how much can the FH boost to the same orbit? if it's more than Ariane 5 ECA then 'the world's most powerful launcher' is a fair statement.FH, about ~20,000 kg to GTO flying full expendable.
Quote from: edkyle99 on 04/12/2019 02:07 pmTerrific launch for SpaceX, and at a key moment with NSSL and NASA's SLS frustration underway. I have only one note about the news coverage. Repeatedly, it is written that Falcon Heavy is "the world’s most powerful operational launcher", etc., which technically is true in terms of liftoff thrust, but FH-2 only put 6,465 kg into GEO-1500-ish m/s. That's only 64% or so of what Ariane 5 ECA has boosted to an equivalent orbit. All of that thrust is neat, but much of it is not being used for the actual payload mission. - Ed KyleIf you expended all 3 cores, (and enlarged the fairing, strengthened the payload adapter) how much can the FH boost to the same orbit? if it's more than Ariane 5 ECA then 'the world's most powerful launcher' is a fair statement.
