Quote from: envy887 on 06/09/2017 01:24 pmQuote from: hkultala on 06/09/2017 05:12 amAt liftoff T/W of 1.5 means that only 66% of all thrust is lost to gravity losses and 33% is doing reasonable work at liftoff moment, not 80% wasted and 20% work like traditional liquid-fueled rockets. Still huge gravity losses, better T/W still helps considerably.It's the other way around, previously rockets have had really lousy T/W's because the engines have been the most expensive part of the rocket.For a given amount of thrust on a long-burning stage, payload to orbit is maximized by having nearly the maximum amount of fuel which gives a low TWR. Fuel only becomes a liability when the tankage to hold it slows the rocket more at the end of flight than the fuel accelerates it at the beginning. For a weight-optimized liquid rocket like Saturn V that happens around TWR of 1.1 or so.Yes, but here we were NOT talking about GIVEN AMOUNT OF THRUST.For for given fixed amount of fuel, the payload to orbit is maximized by having maximum thrust that the structure can stand, to minimize gravity losses.
Quote from: hkultala on 06/09/2017 05:12 amAt liftoff T/W of 1.5 means that only 66% of all thrust is lost to gravity losses and 33% is doing reasonable work at liftoff moment, not 80% wasted and 20% work like traditional liquid-fueled rockets. Still huge gravity losses, better T/W still helps considerably.It's the other way around, previously rockets have had really lousy T/W's because the engines have been the most expensive part of the rocket.For a given amount of thrust on a long-burning stage, payload to orbit is maximized by having nearly the maximum amount of fuel which gives a low TWR. Fuel only becomes a liability when the tankage to hold it slows the rocket more at the end of flight than the fuel accelerates it at the beginning. For a weight-optimized liquid rocket like Saturn V that happens around TWR of 1.1 or so.
At liftoff T/W of 1.5 means that only 66% of all thrust is lost to gravity losses and 33% is doing reasonable work at liftoff moment, not 80% wasted and 20% work like traditional liquid-fueled rockets. Still huge gravity losses, better T/W still helps considerably.It's the other way around, previously rockets have had really lousy T/W's because the engines have been the most expensive part of the rocket.
Not necessarily in this case. The propellant is best burned in vacuum or near-vacuum, where ISP is highest. Carrying as much of that propellant as possible up to booster staging maximizes payload. I'm suspecting that SpaceX is planning to do this. It would be easier to do if the core had less than nine engines. Maybe only five or six. The rocket really only needs three on the core at liftoff, but it needs five or so at staging for T/W>1. - Ed Kyle
Quote from: Semmel on 05/30/2017 09:24 amAlso, what happened to the sea turtles nesting period? This forum was convinced a few month ago that at the current time, no construction would be possible because of the nesting turtles. What happened?I think turtles are in Texas. In Florida the restriction was around bird nesting season in the surrounding scrub. Either the work started before nesting season, or the season ended I guess.Paul
Also, what happened to the sea turtles nesting period? This forum was convinced a few month ago that at the current time, no construction would be possible because of the nesting turtles. What happened?
So according to reddit user /u/aftersteveo all cores are now at the Cape, with B1025 still waiting to be transported to MgGregor for testing. https://www.reddit.com/r/spacex/comments/6ewgm7/rspacex_discusses_june_2017_33/dj2fcc6/
Quote from: tvg98 on 06/18/2017 03:13 pmSo according to reddit user /u/aftersteveo all cores are now at the Cape, with B1025 still waiting to be transported to MgGregor for testing. https://www.reddit.com/r/spacex/comments/6ewgm7/rspacex_discusses_june_2017_33/dj2fcc6/It seems extremely unlikely that they would convert the two boosters in too different places. Why build that capability twice? Also, in the recent factory fly through posted by Elon, there is a reused booster in the factory. That reused booster is most likely the second FH booster.
The Thaicom booster is the side booster we have already seen test fired at McGregor. I was not aware of any flown boosters in Hawthorne, but unless that video is months old one is there. I'd guess that is CRS-9 and we just missed it moving.
Footage is old - several months at least. Flown core is 1023 back when it was being refurbed for a Falcon Heavy side core. That's why the octaweb is missing.
but unless that video is months old one is there.
FH 101 question. We got good closeup video of the Vandenberg strongback during the Iridium launch on Sunday. This strongback looks like its structurally built to support FH. I hadn't seen anything about launching FHs from Vandenberg. Have I missed something?
FH 101 question. We got good closeup video of the Vandenberg strongback during the Iridium launch on Sunday. This strongback looks like its structurally built to support FH. I hadn't seen anything about launching FHs from Vandenberg. Have I missed something?A related question - Is the plan to still build an onshore west coast LZ?
Is the plan to still build an onshore west coast LZ?
Quote from: bdub217 on 06/26/2017 02:07 pmIs the plan to still build an onshore west coast LZ?It has been built for a while now. It's just a little way downhill from the launching pad. It would seem somebody has been throwing up regulatory hurdles against SpaceX actually using that landing pad.--Ninja'd, partially.
Why does it "seem like" regulatory hurdles? Any evidence or just the go-to explanation? This is how rumors start.
..... back when they thought it would be easy to fasten three Falcon first stages side by side. Since then much has changed.
