| Author | Message | ||
     Hughlysses |
I forgot to post this yesterday; SpaceX is attempting to do their first test flight of a complete prototype Starship this week. It’s supposed to fly up to 12.5 km (~7.7 miles), they’ll kill the engines, and it’ll do a controlled “bellyflop” down several miles, they’ll re-light the engines, stand it up, and it’ll land vertically a few hundred feet from where it took off. Elon himself gives it 33% odds of being successful on this first flight. The first attempt was yesterday; they had an automatic abort at T-1.6 seconds due to something with the Raptor engines. They’re getting ready for the second attempt now. Looks like it should happen in the next couple of hours or so, but before 5 PM CST at any rate. Suggested places to watch: Highlights of yesterday’s attempt from SpaceX: | ||
| Hootowl |
Word is they lost pressure in the header tank. This would affect preburner power, which would reduce engine power output. Looked really good, though. All the aero stuff worked, which is really what they’re testing. First major flight (the hops weren’t major) of a full flow combustion stage engine ever. 99% efficiency. That’s 1% less than if God himself stuck the atoms together, according to Musk. | ||
| Hootowl |
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| Rick_a |
Cool flight. Harsh landing. | ||
| Hughlysses |
Despite the landing, Elon was very happy. Soon after he tweeted “Mars, here we come!”  | ||
| Zac4mac |
That rocket is so Flash Gordon it’s not funny. Love to see history following sci-fi. Z | ||
| Pwnzor |
Seriously looks like some heater ducts with aluminum foil fins on it. Awesome flight, right up to the last second. | ||
| Hootowl |
They’re rough prototypes, not meant to be pretty. The thing is huge though. 9 meters across. It’s a flying grain silo with 100 metric ton payload to orbit. With orbital refueling, it’s 100 metric tons to Mars. That’s a game changer. | ||
| Hughlysses |
^ I believe they say it has more internal cargo/passenger volume than a 747. Apparently the green/smokey exhaust near the end is because of the low fuel pressure, resulting in excess oxygen, resulting in internal engine components being combusted.  | ||
| Crusty |
We do live in exciting times! | ||
| Hootowl |
"resulting in excess oxygen, resulting in internal engine components being combusted" Spacex calls that an engine rich exhaust.  It's a full flow stage combustion engine. The oxygen rich side of the preburner is on the ragged edge of eating itself constantly. Up until Spacex developed the metal a couple of years ago, these engines weren't possible. The Soviets created one in the 60s but never flew it; it kept eating itself. The US believed it was Soviet propaganda, because it just wasn't possible for such an engine to exist. | ||
| Chauly |
But certainly possible for it to "exit"? | ||
| Oldog |
Watched the flight it was exciting. men like Musk are Pioneers. they will solve the issues like they have in the past. Was wild watching the Aero test as the ship plummeted to earth flipping up at the last second. BTW I thought that NASA does not have many "main engines" that can start and stop like those did. it was incredible to watch the ship stage the shutdown of the engines and come to a hover then topple over and drop while remaining horizontal. BTW thanks for putting that up .. | ||
| Hootowl |
~But certainly possible for it to "exit"? I'm faster than you | ||
| Rick_a |
It was very 1950's sci fi spaceship looking. | ||
| Chauly |
But I saw it preserved in my e-mail before you replaced it. Did you learn that from Court? | ||
| Hootowl |
Deleted it, corrected it, and reposted it before you posted. I'm faster than you. | ||
| Chauly |
But you left tracks! | ||
| Hootowl |
I said I'm faster, not smarter.  | ||
| 86129squids |
You're a pretty fart smeller. | ||
| Aesquire |
A perfect hang glider, paraglider, & "square" parachute landing involves reaching zero, vertical speed at contact with ground, and zero horizontal speed. That's ideal. Vertical rocket landings attempt that same zero-zero end. In both cases the landing gear is an important limiting factor. It has to absorb the remaining vectors without failure or feeding stresses into the rest of the structure. ( like your spine ) Helicopters have similar limitations. Conventional airplanes allow a greater horizontal speed, wheels on smooth surfaces are nice, but drastic weight limits mean neither a Falcon Heavy or a Lillienthal glider can carry massive landing gear. ( And even a C-130 or Cub doesn't roll to a smooth stop on rougher terrain than a well manicured lawn. Trees, for example, are... Contraindicated. ) I was very impressed. The falling belly first to standing balanced on a pillar of very fast fire transition is impressively tricky. That the landing was a few feet ( And feet per second ) long was unfortunate, but it's a robot and built to test the limits of very bleeding edge hardware. Sure, the sudden green flame is explained by burning metal and subtleties of fluid dynamics... But it sure looks like a Harry Potter or Lord of The Rings dark wizard curse. | ||
| Hootowl |
"Vertical rocket landings attempt that same zero-zero end." It's even worse than that. The Falcon9 rocket, on one engine, running at minimum throttle, when the booster is in its landing phase, and no longer weighs all that much, has too much power to hover. That means that if they hit zero MPH too soon, say, a foot from the ground, back up it goes. They have to hit zero/zero with no room for throttle adjustments. F'ing amazing. | ||
| Hughlysses |
I wish I could remember the quote from “a Christmas Story” where Ralphie damn near shoots his eye out, because it would absolutely apply to this. From Boca Chica this morning: They had planned to move it to the launch pad Monday morning! Aaarrrrggghhh!!!! Apparently the support structure that they use to push it around the construction site partially collapsed. They’re lucky it happened where it did. Lots of speculation on the NASA Spaceflight forum about whether “it’ll buff right out” or “SN9 is toast; cue up SN10.” | ||
| Hootowl |
Wonder whether it damaged the building. | ||
| Hootowl |
Here's a great view of the landing, showing how close they were to the ground when they lit the engines and flipped to vertical. | ||
| Hughlysses |
Wonder whether it damaged the building. It looks okay, but until theyget SN9 out, who knows? Pictures and video shows the big crane “Tankzilla” being walked down the ~1/4 mile from its storage location this evening. It’s gonna be real tricky to lift SN9 within the confines of the high bay. That’ll probably make for some REALLY interesting viewing tomorrow. | ||
| Hughlysses |
The huge crawler crane labeled “Tankzilla” or “Bluto” depending on which videos you watch is now at the high bay. Early video this morning shows the boom tip will just fit inside the top of the opening on the high bay, so hopefully they won’t have to pull roof panels off to lift SN9. As of ~10 AM EST, the boom was swung away from the opening; I’d guess they were installing the spreader and rigging so they can lift SN9. (Message edited by Hughlysses on December 12, 2020) | ||
| Aesquire |
I've spent entirely too much time playing Lunar Lander. Spent at least $100 playing Gravitar. ( The local used arcade game store has my number to call if they get Gravitar, Space Wars, or Gorf ) But in real life I've always had wings, or a parachute, to land. ( crashes don't count? ) If I ever fly a human cuisinart, aka manned multicopter, then I'll have experience with thrust only landings. Regular helicopters don't exactly count... they're aerodynamically complex. | ||
| Hughlysses |
Things are moving along with the effort to get SN9 vertical again. The tip of the boom for the big crane is inside the high bay and riggers are in the process of attaching the rigging to the nose. Man, this is gonna be one tricky operation. NASA Spaceflight added a live feed to cover the operation: | ||
| Steve_mackay |
When I heard it was a thruster that failed. My heart sunk. Guess what I made SpaceX several months ago? Yeah... a "thruster bracket". They are some seriously cool people to work with. |
