Since a number of cool things are happening in space exploration these days, we'll widen the scope of this thread a smidge. Conversation about all things space exploration are welcome, whether it be from NASA, SpaceX, ULA, Blue Origin, or anyone else. Chances are most of the discussion will still be about SpaceX since they love to make things public and fun, but nothing's off limits. I'll eventually get around to modifying the OP to include resources for other companies too, but in the meantime, feel free to post any cool stuff you run across.
Tim Dodd (Everyday Astronaut) - A "random dude" who got really into space (particularly SpaceX). He's a great resource for simple explanations of this stuff, as well as live hosting launches.
USLaunchReport - Lost of videos of the more mundane stuff (e.g., booster recovery operations). Not a ton of commentary.
NASASpaceFlight - Live hosting of most launches including a ton of video of Starlink operations.
Glossary
Spoiler!
Space discussions tend to get a little bogged down in jargon, so here's a list of terms you might encounter. (Others, please let me know of others that should be added.)
ASDS - Autonomous Spaceport Droneship - The "barges" that they sometimes land rockets on.
Dragon - The cone-shaped capsule that sits at the top of the rocket for ISS-bound launches that holds the cargo (or, in the future, humans).
F9 - Falcon 9, the name of the rocket itself.
FH - Falcon Heavy, the three-booster version.
GTO - Geosynchronous Transfer Orbit, a type of orbit that will eventually result in the satellite orbiting the earth as it turns so that it seems to be in the same spot from the ground (such as DirecTV or Dish satellites). These types of launches are particularly challenging because they require a lot of power to get them into the right orbit, leaving very little fuel left for landing.
HIF - Horizontal Integration Facility - the building near the launch pad where they put all of the pieces of the rocket together before rolling it out to the pad.
ISS - The International Space Station
JRTI - Just Read The Instructions, the name of the "barge" that they land on for west-coast launches.
LEO - Low Earth Orbit, a fairly low orbit shared by many satellites and ISS. These launches usually require less power to achieve the proper orbit, so the first stage can often be landed back on land rather than on a drone ship.
LZ1 - Landing Zone 1, basically a big open slab of concrete at Cape Canaveral where the first stage will attempt to land (for some launches).
NET - No Earlier Than, basically the date they're hoping to launch, but rocket launches have a tendency of getting delayed.
OCISLY - Of Course I Still Love You, the name of the "barge" that they land on for east-coast launches.
RTLS - Return to Landing Site, a mission where the first stage comes back and lands at LZ1.
Starship - SpaceX's next-generation rocket (and spacecraft) that will hopefully one day take us to Mars. Starship is the "second stage" that will carry cargo or people, but also refers to the whole system. (It's confusing, but think of it like the Space Shuttle, which was both the shuttle itself and the entire launch system.)
Super Heavy - The giant booster that will carry Starship to space.
A quick test of my steering, and things are looking good as I get ready to roll. My team and I are keen to get moving. One step at a time. pic.twitter.com/XSYfT158AQ
— NASA's Perseverance Mars Rover (@NASAPersevere) March 5, 2021
This image shows two possible routes (blue and purple) to the fan-shaped deposit of sediments known as a delta for NASA’s Perseverance rover, which landed at the spot marked with a white dot in Mars’ Jezero Crater. The yellow line marks a notional traverse exploring the delta. The base image is from the High Resolution Imaging Experiment (HiRISE) camera aboard NASA’s Mars Reconnaissance Orbiter (MRO). [Reply]
I’m on the move! Just took my first test drive on Mars, covering about 16 feet (5 meters). You’re looking at the very beginning of my wheel tracks. Many more to make. pic.twitter.com/7tFIwWFfJ4
— NASA's Perseverance Mars Rover (@NASAPersevere) March 5, 2021
It was later stated that the landing burn was at fault, with Chief Designer Elon Musk stating, “Thrust was low despite being commanded high for reasons unknown at present, hence hard touchdown. We’ve never seen this before.”
As such, had all landing legs locked into place, that would not have protected SN10 from a hard landing. “This was way past leg loads. They got squashed hard,” Elon added.
“Next time, min(imum) two engines all the way to the ground and restart engine 3 if engine 1 or 2 have issues,” Elon pointed out.
Thrust was low despite being commanded high for reasons unknown at present, hence hard touchdown. We’ve never seen this before.
Next time, min two engines all the way to the ground & restart engine 3 if engine 1 or 2 have issues.
Originally Posted by Donger:
It was later stated that the landing burn was at fault, with Chief Designer Elon Musk stating, “Thrust was low despite being commanded high for reasons unknown at present, hence hard touchdown. We’ve never seen this before.”
As such, had all landing legs locked into place, that would not have protected SN10 from a hard landing. “This was way past leg loads. They got squashed hard,” Elon added.
“Next time, min(imum) two engines all the way to the ground and restart engine 3 if engine 1 or 2 have issues,” Elon pointed out.
Thrust was low despite being commanded high for reasons unknown at present, hence hard touchdown. We’ve never seen this before.
Next time, min two engines all the way to the ground & restart engine 3 if engine 1 or 2 have issues.
“SN10 engine was low on thrust due (probably) to partial helium ingestion from fuel header tank. Impact of 10m/s [22 miles per hour] crushed legs & part of skirt,” he tweeted.
A closer look at the landing of SN10 shows it was slightly leaning to one side before exploding.
Musk went on to explain that the helium ingestion was probably the result of a pressurization system that had been added to the methane header tank to fix a problem that occurred in a previous starship prototype, SN8.
“If autogenous pressurization had been used, CH4 bubbles would most likely have reverted to liquid,” he said. “Helium in header was used to prevent ullage collapse from slosh, which happened in prior flight. My fault for approving. Sounded good at the time.” [Reply]
Just prior to SN11 being placed onto the launch mount, SpaceX employees lowered down each and every landing leg. Testing them, so unlike during the SN10 flight; they will hopefully deploy properly this time. pic.twitter.com/LJVl6zpnmo
Things are sounding really good here. Listen to the first sounds of wind captured by my SuperCam microphone. This mic is located at the top of my mast. For this recording, my mast was still down so the sound is a bit muffled. https://t.co/0KpN30oIro
— NASA's Perseverance Mars Rover (@NASAPersevere) March 10, 2021
