YazataAug 22, 2020 05:20 AM (This post was last modified: Aug 22, 2020 05:37 AM by Yazata.)
More tweets!
Tim Dodd, responding to Elon's comment to Corey Bass regarding main Raptor engines doing most of the work in the 90 degree pitch-up "Crazy Elon" landing maneuver, asks, "Raptors will only do majority of the work flipping on the first couple flights right? Won't the hot gas thrusters do more of the work eventually?
Elon replies, "It's counter-intuitive, but Raptor has so much thrust at high Isp with liquid (high density) propellant & pump-fed (light tanks), that it beats hot gas for the flip. That said, hot gas beats the heck out of N2 for orbital maneuvers & stabilizing ship if landing in high winds!"
The topic turns to Falcon 9 reusability and Tim asks, "Now that you're at 6 flights, still think 10 is possible? What do you think will be the limiting factor that will end their service life span?"
Elon, "I don't want to be cavalier, but there isn't an obvious limit. 100+ flights are possible. Some parts will need to be replaced or upgraded. Cleaning all 9 Merlin turbines is difficult. Raptor is way easier in this regard, despite being a far more complex engine."
Vivien asks, "How often do you need to replace individual Merlins on F9 before reuse?"
Elon, "Almost never need to replace whole engine, but some individual parts like turbine wheels need to be replaced over time. Similar to a jet engine."
Tim, "Is Raptor mostly more reuse friendly due to methane burning clean with no soot or does it have more to do with full flow running so cool through each preburner / turbine? I still have a hard time grasping how such high pressure can be better re-use wise, but it seems to somehow!"
Elon, "Not having long chain hydrocarbons & lowering preburner combustion temperature make a big difference"
YazataAug 23, 2020 05:27 PM (This post was last modified: Aug 24, 2020 02:04 AM by Yazata.)
Static Fire Day
11:24 AM CDT - Road is closed, pad is clear.
Edit: 12:52 CDT - They appeared to fuel SN6, then detanked it. A number of cars have returned to the launch area and the "party bus", a luxury SX coach at the viewing area by the Rocket Diner has left again. (Speculation is that was Elon and maybe some investors/potential investors that SX is courting.) SN6's dents have reappeared and it's depressed
Unknown if that's it for the day or whether they will try to recycle.
Edit: 2:29 CDT - Pad is clear again. Looks like everyone has had lunch and they are having another go.
Edit: 7:18 CDT - Pad is clear again. Third try and third time's the charm!
SN6 just pulled off what appeared to be a successful static fire.
Wow, that's a surprise with respect to the usual "another day, week, or month" procrastination. Glad to see those overall one-year stretches between the next hop or flight finally being threatened with extinction.
They seem to be satisfied, since today's and tomorrow's backup dates have been cancelled.
Next up is the hop flight set for this coming Friday.
Right now, they are installing one of those big 20 ton ballast mass cubes atop SN6. It's apparently necessary to get the weight and weight distribution needed for flight.
In other news, they have started another level of the High Bay. Based on some hints by Elon, speculation is that this is the last level before they install the roof and maybe a bridge crane up by the roof to pick up and move prototypes and pieces.
YazataAug 27, 2020 03:47 AM (This post was last modified: Aug 27, 2020 06:23 AM by Yazata.)
The SN6 hop-flight appears to have been pushed back a day to NET (not earlier than) Saturday August 29, with Sunday and Monday as backup days. The FAA has issued revised TFRs.
Readying SN6 seems to be going slower than planned. But... there are those who are saying that Elon wants to be in Boca Chica for the flight and he's booked on Friday in San Francisco for the Neuralink presentation.
YazataAug 28, 2020 01:31 AM (This post was last modified: Aug 28, 2020 03:13 AM by Yazata.)
Today is the one-year anniversary of Hoppy's famous flight, when a homely Texas tank proved that water towers can indeed fly!
Jack Beyer says, "Today is the 1 year anniversary of Starhopper's 150m hop. Still some of the most fun I've ever had, shooting one of the coolest things I've ever photographed/witnessed. Mmm methalox mach diamonds."
So what is Hoppy doing these days? It's still working for SpaceX. Chris Bergin says, "Now multitasking as a PA system, weather radar, a host of close circuit TV cam views of Starship testing, safety lights and providing workers with a cover during lunch." (There are actually picnic tables under Hoppy.)
And ironically, Hoppy seems to have been fitted with new plumbing and may have come full circle in life, becoming the water tower that people originally thought it was.
^ ^ ^ ^ ^ ^ ^
A century or more from now, I suppose it would be near impossible for Hoppy to be standing as an historical monument in the middle of an environmentally protected Martian town like Barsoom or Bradbury or Clarkesville or Podkayne or Wells. Even taking it apart to transport it in many, many multiple shipments of pieces would be... a mess in terms of reassembly. Re-welding on top of old welds that had been plasma-cut.
YazataAug 28, 2020 08:03 PM (This post was last modified: Aug 28, 2020 08:51 PM by Yazata.)
Today's news - SN6's hop has been pushed back again, to Sunday this time. Dunno if they need more time to prepare it (workers continue to busily work on it) or whether the delay is to give Elon more time to fly in from San Francisco after Neuralink.
They are finishing up the new High Bay which seems to be as tall as planned. Now it needs a roof. Construction of the first Super Heavy is expected to start soon.
A second test stand has appeared at the launch area, with simpler plumbing than the first and with the hydraulic thrust ram installed, perhaps permanently. So this second stand looks like it's for liquid nitrogen cryo pressure tests. Its first assignment looks like it will be 7.1's test-to-destruction. 7.1 will have a new-design thrust dome welded to a whole thrust section, will be placed under load by the thrust ram simulating rocket engine thrust and will be pressurized until it bursts, to see what the limits of the new design are. Mary has already spotted 7.1's parts being assembled.
Meanwhile the first stand has all the LOX and LCH4 connections and will presumably be for static fires and launches. It's where SN6 currently is.
The Superheavy launch stand continues to take shape atop the deep piles and the hexagonal foundation laid atop them. It will apparently sit up off the ground quite a ways, atop six huge concrete columns, with a flame diverter of some sort underneath. We've seen all the dust and smoke that one Raptor can kick up. Super Heavy will have as many as 30 Raptors (fewer in the early test versions). So all that rocket blast needs to be deflected away in a safe direction and not bounced back up at the rocket.
SN5 has rolled out of the Midbay, perhaps to watch its compatriot SN6 fly.
SN8 is being stacked in the Midbay. Still no fins or nose, which are expected soon. Nobody is quite sure what the fins will look like or how they will be attached.
Parts of SN9 are making their appearance. The new thing with them is that one side of the SN9 rings is covered with welded steel studs for attaching Space Shuttle style thermal tiles. There are thousands of very precisely placed studs, obviously the work of the new robots.
Regarding Hoppy - I don't know if it will ever travel to Mars (it's awfully big) but Elon and Co. seem to perceive its historical importance. They have retained Mark 1's nose as well. I expect some kind of Rocket Garden to emerge in Boca at some point, preserving some of the old historical highlights on the way to operational Starships (which hopefully will transform space travel and open up the whole Solar System). Kind of like NASA's rocket gardens in Houston and at Cape Canaveral.
YazataAug 30, 2020 05:07 PM (This post was last modified: Aug 31, 2020 02:03 AM by Yazata.)
SN6 News 11:05 AM CDT: Pad cleared and roadblocks are up. No visible tank farm activity yet.
Two intruders on foot spotted in the exclusion area. They were spotted walking down the road past the evacuated launch site. When they saw the police roadblock, they set off through the brush away from the road. Then they hunkered down and changed their clothes. After that LabPadre's cam lost sight of them. Speculation is that they were illegals who picked a bad spot to cross the nearby border. No sign of SpaceX security, local police or Border Patrol. (People were waiting for a blackhawk helicopter to swoop in, but didn't happen.)
12:00 CDT: LabPadre reports that Customs and Border Protection have two individuals in custody and Lab's told the exclusion area is once again clear and that the SN6 test is proceeding again.
1:30 CDT -- Vehicle has been depressurized. Detanking underway. Unclear if they will be recycling.
2:06 CDT -- Cars returned to the pad, then left again. Pad is once again clear. Don't see much activity from the tank farm yet.
2:35 CDT -- Tank farm venting indicates renewed activity there.
3:02 CDT -- Tanking underway. LabPadre reports that SpaceX has warned the Sheriffs that they will need to sound the 10 minute warning siren soon.
3:08 CDT -- Siren sounding!! Crowd of SpaceX workers gathered at the roadblock.
3:13 CDT -- Looks like another abort.
3:39 CDT -- LabPadre says that "a buzzard" told him that the abort was due to high wind. Wind currently 20 mph, gusting to 30. SpaceX isn't giving up though and are prepared for a third try. Things currently in hold.
They eventually called it quits for the day. Tomorrow and Tuesday are backup days.
YazataSep 2, 2020 03:49 AM (This post was last modified: Sep 2, 2020 04:00 AM by Yazata.)
Boca news: SN6 hop is now scheduled for Thursday, provided that winds calm down. Work continues on the Super Heavy launch mount. The new high bay is being roofed.
And there was some kind of 'Humans on Mars' virtual event on Monday August 31st, and Elon (who was in Germany at the time) participated via some futuristic new technology called the "telephone". (You can actually speak in Germany and be heard in the US!)
Among the gems that Elon dropped:
Elon says that they are making good progress in Boca. The thing that really impedes progress is the production system. A year ago there was nothing there and now they have quite a bit of production capability. So they are able to make more and more ships.
Construction on the first Super Heavy booster prototype will begin this week. Elon called it "Booster Prototype 1".
They are trying to simplify the configuration of the Super Heavy so it may go from 31 engines to 28. Elon says that's still a lot of engines. There will be an outer ring of 20 thrust-optimized Raptors at about 300 tons thrust each, surrounding an inner core of eight Raptors at about 210 tons each, but able to be throttled and gimballed for control. Totals somewhere around 7,500 tons total for a thrust/weight ratio for the whole-stack vehicle of about 1.5/1.
The goal is for Starship to be able to put over 100 tons of payload into orbit.
The first orbital flight tests will probably be next year.
When asked about Starship cabin development, Elon said that isn't very far along at this point. He says that they plan to have many developmental test flights before they put human beings aboard. He mentioned hundreds of satellite launches.
He warns that the first orbital Starship flights might not work, since "we are in uncharted territory".
They hope to achieve a 200 to 1 thrust to weight ratio with a thrust-optimized version of Raptor. That would beat SpaceX's smaller Merlin engine which is the current record holder, at about 180 to 1. Achieving 200 to 1 would be close to the theoretical limits for that engine, given the physics.
Elon says that things will be "very hard and dangerous" for the first Mars settlers. A difficult thing, not for the faint of heart. There's a good chance you will die. Even if you survive, life is going to be tough and grueling. -- But if it succeeds, it will be glorious.
Aug 22, 2020 05:20 AM
(This post was last modified: Aug 22, 2020 05:37 AM by Yazata.)
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