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Just want to point out some misconceptions here: Arguably, the Space Shuttle was the first launch system to reuse the first stage, and the first to prove retro-

by Hypx 9y ago

Just want to point out some misconceptions here: Arguably, the Space Shuttle was the first launch system to reuse the first stage, and the first to prove retro-propulsion landing was the Delta Clipper (on Earth anyways, supersonic retro-propulsion was used on other planetary bodies earlier). First private company to refly a spacecraft was probably SpaceShipOne, although this was suborbital not orbital. Not saying what SpaceX achieved isn't impressive, it just needs some context.

vkou 9y ago
The difference between a suborbital and an orbital flight is the difference between dropping a basketball, and scoring a three point shot from the other side of the field. Attaining orbit required 20 times the energy that spaceship one's flight did - it's why landing airplanes is trivial, and landing rockets is so hard.
ChuckMcM 9y ago
Let's look at the claims from the parent: * re-usability of the first stage of an orbital class rocket, I think the shuttle argument has some merit, it was certainly designed to be re-usable. However the first stage was a blend of the SSME's and the SRB's. While the SRB's were "refurbed" it really was re-manufactured. The shuttle and its SSMEs were closer to what F9 does today. * the first to prove out supersonic retro-propulsion Here the key is supersonic retro-propulsion. They really were the first people to light up a rocket engine facing the 'wrong' way of a supersonic spacecraft. NASA's interplanetary systems have all used parachutes to get into the sub-sonic regime before firing retro-rockets. Neither retro-propulsion in orbit (nominally a vacuum) or on the Moon count as supersonic. * and the first private company to re-fly a spacecraft (the Dragon Capsule). If you add 'orbital' spacecraft then it does work (private company, orbital craft). If you consider suborbital flights like Spaceship One then all of the sounding rockets that are fired doing ionosphere research probably count too. With luck, next month they will be the first company ever to launch and recover a rocket with 27 engines in the first stage. They are also the first company to launch two rockets into orbit in a single weekend. So at what point would SpaceX's achievements become "impressive" for you without having to add context?
- Hypx 9y ago
  This claim needs some scrutiny: >> * the first to prove out supersonic retro-propulsion > Here the key is supersonic retro-propulsion. They really were the first people to light up a rocket engine facing the 'wrong' way of a supersonic spacecraft. NASA's interplanetary systems have all used parachutes to get into the sub-sonic regime before firing retro-rockets. Neither retro-propulsion in orbit (nominally a vacuum) or on the Moon count as supersonic. All retropulsive landings are rockets facing the "wrong" way. That's true on Mars, the Moon, or Earth. By the semantics of your argument, neither does the Falcon 9 experience supersonic retropulsive landing, since the only time it fires at supersonic speeds is in the near vacuum state of the upper atmosphere. The descent down to Earth is a guided free-fall and the last step happens at subsonic speeds. On Mars, terminal velocity for a probe is supersonic, so the parachute stage is required to reach subsonic speeds. It basically replaces the guided free-fall of the Falcon 9 rocket, and make things harder, not easier. It should be pointed out that the full process of landing on Mars involves an insane Rube Goldberg contraption of heat shield, parachutes, retropulsive rockets, airbags, and sometimes a skyscrane. Claiming that what SpaceX is doing is a harder problem than this is simply wrong. Finally, the Delta Clipper did pretty much exactly what the Falcon 9 did, and so did Blue Origin with their New Shepard rocket. So the concept in its near entirety was well-known for a while. > They are also the first company to launch two rockets into orbit in a single weekend. Not from the same launchpad. Many organizations have launched rockets nearly back-to-back, some even from the same launchpad. > So at what point would SpaceX's achievements become "impressive" for you without having to add context? Not really what was being argued here. Certainly, what SpaceX has done is impressive with or without context. But the claim that they are magically beyond everyone else is just wrong. Looking at their achievements in context shows their limitations, and that they are not exactly the "first to X" where X is something someone else has long figured out but the poster is unaware.
deleted 9y ago
[deleted]

by Hypx 9y ago

vkou 9y ago

The difference between a suborbital and an orbital flight is the difference between dropping a basketball, and scoring a three point shot from the other side of the field. Attaining orbit required 20 times the energy that spaceship one's flight did - it's why landing airplanes is trivial, and landing rockets is so hard.

ChuckMcM 9y ago

Let's look at the claims from the parent: * re-usability of the first stage of an orbital class rocket, I think the shuttle argument has some merit, it was certainly designed to be re-usable. However the first stage was a blend of the SSME's and the SRB's. While the SRB's were "refurbed" it really was re-manufactured. The shuttle and its SSMEs were closer to what F9 does today. * the first to prove out supersonic retro-propulsion Here the key is supersonic retro-propulsion. They really were the first people to light up a rocket engine facing the 'wrong' way of a supersonic spacecraft. NASA's interplanetary systems have all used parachutes to get into the sub-sonic regime before firing retro-rockets. Neither retro-propulsion in orbit (nominally a vacuum) or on the Moon count as supersonic. * and the first private company to re-fly a spacecraft (the Dragon Capsule). If you add 'orbital' spacecraft then it does work (private company, orbital craft). If you consider suborbital flights like Spaceship One then all of the sounding rockets that are fired doing ionosphere research probably count too. With luck, next month they will be the first company ever to launch and recover a rocket with 27 engines in the first stage. They are also the first company to launch two rockets into orbit in a single weekend. So at what point would SpaceX's achievements become "impressive" for you without having to add context?

Hypx 9y ago
This claim needs some scrutiny: >> * the first to prove out supersonic retro-propulsion > Here the key is supersonic retro-propulsion. They really were the first people to light up a rocket engine facing the 'wrong' way of a supersonic spacecraft. NASA's interplanetary systems have all used parachutes to get into the sub-sonic regime before firing retro-rockets. Neither retro-propulsion in orbit (nominally a vacuum) or on the Moon count as supersonic. All retropulsive landings are rockets facing the "wrong" way. That's true on Mars, the Moon, or Earth. By the semantics of your argument, neither does the Falcon 9 experience supersonic retropulsive landing, since the only time it fires at supersonic speeds is in the near vacuum state of the upper atmosphere. The descent down to Earth is a guided free-fall and the last step happens at subsonic speeds. On Mars, terminal velocity for a probe is supersonic, so the parachute stage is required to reach subsonic speeds. It basically replaces the guided free-fall of the Falcon 9 rocket, and make things harder, not easier. It should be pointed out that the full process of landing on Mars involves an insane Rube Goldberg contraption of heat shield, parachutes, retropulsive rockets, airbags, and sometimes a skyscrane. Claiming that what SpaceX is doing is a harder problem than this is simply wrong. Finally, the Delta Clipper did pretty much exactly what the Falcon 9 did, and so did Blue Origin with their New Shepard rocket. So the concept in its near entirety was well-known for a while. > They are also the first company to launch two rockets into orbit in a single weekend. Not from the same launchpad. Many organizations have launched rockets nearly back-to-back, some even from the same launchpad. > So at what point would SpaceX's achievements become "impressive" for you without having to add context? Not really what was being argued here. Certainly, what SpaceX has done is impressive with or without context. But the claim that they are magically beyond everyone else is just wrong. Looking at their achievements in context shows their limitations, and that they are not exactly the "first to X" where X is something someone else has long figured out but the poster is unaware.

deleted 9y ago

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