Quote from: EspenU on 06/03/2020 02:30 pmQuote from: woods170 on 06/03/2020 02:09 pmQuote from: EspenU on 06/03/2020 01:45 pmQuote from: woods170 on 06/03/2020 01:19 pmSo, the NASA worm will be erased and the stage will be refurbished to fly another day.Do you think there is a chance that they will leave the worm in place and only use this booster for NASA cargo missions? That would of course mean that NASA first would have to be ok with using a booster that has landed at sea.NASA don't get to pick the booster that cargo Dragon flies on. However, NASA does have the right to decide which booster Cargo Dragon does NOT fly on.Remember, for both CRS-2 and CCP NASA is buying a service. They are not buying a booster and a spaceship. NASA does however have a stipulation in place that it wants brand new launchers for CCP missions. NASA, so far, has not allowed SpaceX to fly a drone ship landed booster on a CRS mission. This is based on the original CRS contract which also stipulated all-new boosters for each CRS launch. This was later amended to allow land-landed boosters to be re-flown on CRS missions. But not ocean landed boosters. As far as I know that stipulation is also in place for the follow-on CRS-2 contract.Yes, that was my point. SpaceX could just leave the logos in place and then use the booster for NASA CRS-2 missions (if NASA agrees to use barge landed boosters). Do you think that's a realistic option?Well this means that this booster has a chance of being reused on CC. However the land landing vs barge landing is not addressed! So I'm an outsider guessing. Others herw may now much better.https://twitter.com/nextspaceflight/status/1268316718750814209QuoteSpaceX has been given NASA approval to fly flight-proven Falcon 9 and Crew Dragon vehicles during Commercial Crew flights starting with Post-Certification Mission 2, per a modification to SpaceX's contract with NASA. https://t.co/BxHlFqt9sK?amp=1
Quote from: woods170 on 06/03/2020 02:09 pmQuote from: EspenU on 06/03/2020 01:45 pmQuote from: woods170 on 06/03/2020 01:19 pmSo, the NASA worm will be erased and the stage will be refurbished to fly another day.Do you think there is a chance that they will leave the worm in place and only use this booster for NASA cargo missions? That would of course mean that NASA first would have to be ok with using a booster that has landed at sea.NASA don't get to pick the booster that cargo Dragon flies on. However, NASA does have the right to decide which booster Cargo Dragon does NOT fly on.Remember, for both CRS-2 and CCP NASA is buying a service. They are not buying a booster and a spaceship. NASA does however have a stipulation in place that it wants brand new launchers for CCP missions. NASA, so far, has not allowed SpaceX to fly a drone ship landed booster on a CRS mission. This is based on the original CRS contract which also stipulated all-new boosters for each CRS launch. This was later amended to allow land-landed boosters to be re-flown on CRS missions. But not ocean landed boosters. As far as I know that stipulation is also in place for the follow-on CRS-2 contract.Yes, that was my point. SpaceX could just leave the logos in place and then use the booster for NASA CRS-2 missions (if NASA agrees to use barge landed boosters). Do you think that's a realistic option?
Quote from: EspenU on 06/03/2020 01:45 pmQuote from: woods170 on 06/03/2020 01:19 pmSo, the NASA worm will be erased and the stage will be refurbished to fly another day.Do you think there is a chance that they will leave the worm in place and only use this booster for NASA cargo missions? That would of course mean that NASA first would have to be ok with using a booster that has landed at sea.NASA don't get to pick the booster that cargo Dragon flies on. However, NASA does have the right to decide which booster Cargo Dragon does NOT fly on.Remember, for both CRS-2 and CCP NASA is buying a service. They are not buying a booster and a spaceship. NASA does however have a stipulation in place that it wants brand new launchers for CCP missions. NASA, so far, has not allowed SpaceX to fly a drone ship landed booster on a CRS mission. This is based on the original CRS contract which also stipulated all-new boosters for each CRS launch. This was later amended to allow land-landed boosters to be re-flown on CRS missions. But not ocean landed boosters. As far as I know that stipulation is also in place for the follow-on CRS-2 contract.
Quote from: woods170 on 06/03/2020 01:19 pmSo, the NASA worm will be erased and the stage will be refurbished to fly another day.Do you think there is a chance that they will leave the worm in place and only use this booster for NASA cargo missions? That would of course mean that NASA first would have to be ok with using a booster that has landed at sea.
So, the NASA worm will be erased and the stage will be refurbished to fly another day.
SpaceX has been given NASA approval to fly flight-proven Falcon 9 and Crew Dragon vehicles during Commercial Crew flights starting with Post-Certification Mission 2, per a modification to SpaceX's contract with NASA.
Quote from: Oersted on 06/03/2020 11:45 am....For all of those reasons.. Save the stage!How deep are the pockets of the Smithsonian and its sponsors? Perhaps they could chip in. ...And get Hopper as well: it deserves a better fate than glorified radar and surveillance video pole.Emphasis mine.Because it flew a single Grasshopper style mission? In case you had not noticed: Starhopper didn't do anything that hadn't already been done by Grasshopper. And the latter is still sitting pretty in Texas instead of in the Smithsonian.
....For all of those reasons.. Save the stage!How deep are the pockets of the Smithsonian and its sponsors? Perhaps they could chip in. ...And get Hopper as well: it deserves a better fate than glorified radar and surveillance video pole.
Nice to see Yeager's congratulations. But it reminds me of how deeply hurt Elon was by Neil Armstrong and Gene Cernan criticizing commercialization of NASA spaceflights way back in 2012. Elon almost cried on national TV, he was so distraught. I still remember seeing that. Hopefully he feels vindicated now.https://www.space.com/14936-spacex-ceo-elon-musk-60-minutes-interview.htmlNeither Armstrong nor Cernan lived to see the DM-2 flight, but I hope they would have changed their minds and offered their congratulations too.
The Apollo Astronauts Tribute to SpaceXWhen I saw Elon Musk tear up on 60 Minutes facing the verbal assault from one of his heroes — Apollo astronaut Gene Cernan — I knew what I had to do.It has taken a bit of effort over the past months, but today I gave this to Elon and all of the SpaceX team, and it was very well received. =)
Quote from: Kabloona on 06/04/2020 04:03 pmNice to see Yeager's congratulations. But it reminds me of how deeply hurt Elon was by Neil Armstrong and Gene Cernan criticizing commercialization of NASA spaceflights way back in 2012. Elon almost cried on national TV, he was so distraught. I still remember seeing that. Hopefully he feels vindicated now.https://www.space.com/14936-spacex-ceo-elon-musk-60-minutes-interview.htmlNeither Armstrong nor Cernan lived to see the DM-2 flight, but I hope they would have changed their minds and offered their congratulations too.https://www.flickr.com/photos/jurvetson/7547788856QuoteThe Apollo Astronauts Tribute to SpaceXWhen I saw Elon Musk tear up on 60 Minutes facing the verbal assault from one of his heroes — Apollo astronaut Gene Cernan — I knew what I had to do.It has taken a bit of effort over the past months, but today I gave this to Elon and all of the SpaceX team, and it was very well received. =)
Then I approached Gene Cernan, and held my breath. I figured it would be a bit more difficult to break from the social proof of his esteemed colleagues. And so he listened. As with every Apollo astronaut who signed this photo, I was able to talk about SpaceX and answer his questions. Gene was interested in who financed SpaceX — what big money interests got it going. I told him that Elon Musk personally financed the company for all of its first $100 million, when no one else would bet on the venture, and he saw it through thick and thin, including the first three launches of the Falcon 1, all of which failed spectacularly. As I told him these stories of heroic entrepreneurship, I could see his mind turning. He found a reconciliation: “I never read any of this in the news. Why doesn’t the press report on this?”
Parts 1 to 4 step-by-step infographic of #NASA & SpaceX’s #Falcon 9 #Crew #Dragon #Demo-2 mission. More updates at tonybela.com as mission unfolds. Cheers,Tony Godspeed @elonmusk @MarcusHouseGame @AmyShiraTeitel @DJSnM @NASA @SpaceX @Erdayastronaut
Update: The mission so far, infographic of @NASA & @SpaceX’s #Falcon 9 #Crew #Dragon #Demo-2 mission. Large free printable version go to tonybela.com Cheers,Tony @elonmusk @JimBridenstine @MarcusHouseGame @AmyShiraTeitel @DJSnM @Erdayastronaut @Cmdr_Hadfield
Alternative version on white
Free to use for non-profit and educational purposes.
I agree. Starhopper is worthy of preserval not so much because if its flight history but because it represents the very earliest example of a whole new method of building rockets.Our generation can go and see The Spirit of St. Louis, Glamourous Glennis and Enola Gay in museums. Would be cool if future generations had the same opportunity with this historic SpaceX hardware.
Quote from: Oersted on 06/04/2020 10:53 amI agree. Starhopper is worthy of preserval not so much because if its flight history but because it represents the very earliest example of a whole new method of building rockets.Our generation can go and see The Spirit of St. Louis, Glamourous Glennis and Enola Gay in museums. Would be cool if future generations had the same opportunity with this historic SpaceX hardware. Let me add that all the planes you mentioned are nicer to see than Starhopper, that looks like a huge trash can.
Did this documentary air yet? - Any good?https://corporate.discovery.com/discovery-newsroom/walton-goggins-to-narrate-discovery-and-science-channels-epic-documentary-nasa-spacex-journey-to-the-future-giving-viewers-a-rare-glimpse-inside-nasa-and-spacex-headquart/Would love to see it...
I saw that Bob and Doug agreed the ride on the Falcon 9 first stage was very smooth. This makes sense to me, it's sort of the difference between a single-cylinder dirt bike and a v-8 luxury car. They also said they were surprised at how rough the ride felt on the second stage. But again, I think that makes sense because the combustion is never going to be totally smooth so it will probably feel like 100 little explosions happening every second. The G-force range is probably fairly tight, but the oscillations within that range will be very obvious to human passengers. Anybody with more hands-on knowledge of rocket propulsion care to comment?I'm also curious if a smaller engine has more or less combustion instability. For example, would a single BE-4 be smoother or rougher (in theory) than a single Raptor? Even if the Raptor has large thrust oscillations, I think that using lots of them together averages out those oscillations nicely to give a smooth ride. But I guess if a big engine also has bigger thrust oscillations then that is kind of a lose-lose if you're interested in a smooth ride. I'd like to hear what you all think.
Quote from: kendalla59 on 06/05/2020 07:12 pmI saw that Bob and Doug agreed the ride on the Falcon 9 first stage was very smooth. This makes sense to me, it's sort of the difference between a single-cylinder dirt bike and a v-8 luxury car. They also said they were surprised at how rough the ride felt on the second stage. But again, I think that makes sense because the combustion is never going to be totally smooth so it will probably feel like 100 little explosions happening every second. The G-force range is probably fairly tight, but the oscillations within that range will be very obvious to human passengers. Anybody with more hands-on knowledge of rocket propulsion care to comment?I'm also curious if a smaller engine has more or less combustion instability. For example, would a single BE-4 be smoother or rougher (in theory) than a single Raptor? Even if the Raptor has large thrust oscillations, I think that using lots of them together averages out those oscillations nicely to give a smooth ride. But I guess if a big engine also has bigger thrust oscillations then that is kind of a lose-lose if you're interested in a smooth ride. I'd like to hear what you all think.Discussed a couple of pages ago.https://forum.nasaspaceflight.com/index.php?topic=51080.msg2091377#msg2091377Re your final question, if you're comparing engines using the same propellants and cycle, the larger the engine, the larger the amplitude of vibrations, though the frequencies will probably be different. So if you want the smoothest ride, multiple small engines are probably going to be smoother than one large engine, all other things being equal.As for combustion stability, generally speaking the larger the chamber, the harder it is to eliminate instability (read up on the F-1 engine development and how difficult it was to make that engine stable).
Quote from: Kabloona on 06/05/2020 11:09 pmQuote from: kendalla59 on 06/05/2020 07:12 pmI saw that Bob and Doug agreed the ride on the Falcon 9 first stage was very smooth. This makes sense to me, it's sort of the difference between a single-cylinder dirt bike and a v-8 luxury car. They also said they were surprised at how rough the ride felt on the second stage. But again, I think that makes sense because the combustion is never going to be totally smooth so it will probably feel like 100 little explosions happening every second. The G-force range is probably fairly tight, but the oscillations within that range will be very obvious to human passengers. Anybody with more hands-on knowledge of rocket propulsion care to comment?I'm also curious if a smaller engine has more or less combustion instability. For example, would a single BE-4 be smoother or rougher (in theory) than a single Raptor? Even if the Raptor has large thrust oscillations, I think that using lots of them together averages out those oscillations nicely to give a smooth ride. But I guess if a big engine also has bigger thrust oscillations then that is kind of a lose-lose if you're interested in a smooth ride. I'd like to hear what you all think.Discussed a couple of pages ago.https://forum.nasaspaceflight.com/index.php?topic=51080.msg2091377#msg2091377Re your final question, if you're comparing engines using the same propellants and cycle, the larger the engine, the larger the amplitude of vibrations, though the frequencies will probably be different. So if you want the smoothest ride, multiple small engines are probably going to be smoother than one large engine, all other things being equal.As for combustion stability, generally speaking the larger the chamber, the harder it is to eliminate instability (read up on the F-1 engine development and how difficult it was to make that engine stable).I don't think it was necessarily combustion instability. Considering the short-coupled system of the second stage, it's quite possible oscillations were due to the servo frequencies in the Merlin 1DVac steering algorithms. In order to meet minimum orbit dispersal, they probably have the steering gains set quite high. It would tell us a lot if someone asked the crew whether the "roughness" was in-and-out of the seat (combustion variations or pogo, which doesn't have to be severe) or side-to-side (probably engine gimbaling, with a feel similar to riding a wooden roller coaster.)
