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Orion is being qualified for faster reentry. Dragon currently only qualified for LEO reentry. But they both use ablative heatshields which scale in a straightfo

Orion is being qualified for faster reentry. Dragon currently only qualified for LEO reentry. But they both use ablative heatshields which scale in a straightforward way to higher speed reentries. Orion also has more propellant, more delta-v, so it has more post-separation maneuvering capability. Dragon would need either expanded tanks on board or maybe some extra propulsion capability in the trunk or perhaps docking with a small propulsion module (think like how the Apollo command module docked with the LM in Apollo 13 and used that for maneuvering delta-v). Neither of those things are huge. There are a few other things that are relatively minor, like shielding (literally just mass of plastic, very little engineering involved) and extra consumables for longer free flight mission and getting Falcon Heavy fully up to Falcon 9 human rating standards (pretty straightforward as it’s almost identical to Falcon 9 but with 2 side boosters). You could test those things on an uncrewed test flight fairly cheaply. In some ways, it’d be safer than Orion/SLS as the vehicle and spacecraft have a lot more flight history already.

panick21_ 5y ago
The Dragon Heat Shield was designed for Moon reentry as far as we know. If they actually had to change the heat shield it would be quite a bit more work.
- Robotbeat 5y ago
  That’s right. But there’s a bunch of engineering that goes into finally qualifying something for lunar flight. Remember they haven’t been planning to fly dragon the lunar vicinity for several years now since the pivot to Starship, so there are dozens of tiny things that would need to be tweaked to make that demonstrable again. I don’t think it will take SpaceX very long. I think they could do it in about a year from the word “go.” It took them just a few months to design, build, and qualify the bubble cupola window thing for Inspiration 4.
bryanlarsen 5y ago
Past NASA administrator Bolden said that NASA would never human rate Falcon Heavy, so SpaceX didn't design Falcon Heavy for human rating. There are a couple of places where the margin is less than the 1.4 that NASA considers to be a requirement for human rating. The walls of the F9 are strong enough to have a 1.4 margin on their own, but adding the force and torsion of 2 extra boosters lowers the margin significantly. Getting those margins up to 1.4 would require a fundamental redesign and that's something SpaceX will never do. They expect Starship to become operational before any Falcon Heavy redesign ever could. But in the opinion of experts Falcon Heavy is considerably safer than the human rated SLS[1] and massively safer than the Shuttle ever was, so human rating Falcon Heavy is just a matter of NASA swallowing their pride and acknowledging that. 1: https://caseyhandmer.wordpress.com/2021/02/24/sls-is-cancellation-too-good/ https://caseyhandmer.wordpress.com/2021/02/24/sls-is-cancell...
- Robotbeat 5y ago
  Bolden has said a lot of things dismissive of SpaceX, and they haven’t turned out to be very accurate. The Administrator has Congressional political constraints and is part of the aerospace old guard that had a sort of learned-helplessness about new aerospace endeavors. Falcon Heavy can absolutely be human rated. There’s also the possibility of LEO rendezvous between a Dragon launched on a Falcon 9 and a filled Falcon Heavy upper stage with a docking port on it.
  - bryanlarsen 5y ago
    Falcon Heavy cannot be human rated under current NASA design guidelines. So NASA would have to change those guidelines to human rate Falcon Heavy. Which they should absolutely do -- being able to closely inspect returned boosters gives far better data than design guidelines based on computer models. That's the plan for Starship. It doesn't follow the NASA man rating design guidelines either, AFAIK. But SpaceX doesn't need NASA human rating to fly non-NASA personnel and have no immediate plans to fly NASA astronauts on Starship. By the time they do compete for a NASA human contract with Starship they expect to have enough flight data to meet NASA's standard of less than 1/500th of a chance of loss of mission using hard test data rather than computer modelling. Even Bolden has changed his tune now that he's retired and doesn't have to answer to Congress. He says that SLS should be cancelled. I wonder if Senator Shelby will change his tune after he retires? Somehow I doubt it.
    - panick21_ 5y ago
      Can you be more specific about what is strictly outside human rating? Nothing in Starship should be outside of human rating specifications. They have never done those for powered landings but its not outside of scope.
      - bryanlarsen 5y ago
        The most egregious is that Starship doesn't have a full envelope launch escape system.

panick21_ 5y ago

The Dragon Heat Shield was designed for Moon reentry as far as we know. If they actually had to change the heat shield it would be quite a bit more work.

Robotbeat 5y ago
That’s right. But there’s a bunch of engineering that goes into finally qualifying something for lunar flight. Remember they haven’t been planning to fly dragon the lunar vicinity for several years now since the pivot to Starship, so there are dozens of tiny things that would need to be tweaked to make that demonstrable again. I don’t think it will take SpaceX very long. I think they could do it in about a year from the word “go.” It took them just a few months to design, build, and qualify the bubble cupola window thing for Inspiration 4.

bryanlarsen 5y ago

Past NASA administrator Bolden said that NASA would never human rate Falcon Heavy, so SpaceX didn't design Falcon Heavy for human rating. There are a couple of places where the margin is less than the 1.4 that NASA considers to be a requirement for human rating. The walls of the F9 are strong enough to have a 1.4 margin on their own, but adding the force and torsion of 2 extra boosters lowers the margin significantly. Getting those margins up to 1.4 would require a fundamental redesign and that's something SpaceX will never do. They expect Starship to become operational before any Falcon Heavy redesign ever could. But in the opinion of experts Falcon Heavy is considerably safer than the human rated SLS[1] and massively safer than the Shuttle ever was, so human rating Falcon Heavy is just a matter of NASA swallowing their pride and acknowledging that. 1: https://caseyhandmer.wordpress.com/2021/02/24/sls-is-cancellation-too-good/ https://caseyhandmer.wordpress.com/2021/02/24/sls-is-cancell...

Robotbeat 5y ago
Bolden has said a lot of things dismissive of SpaceX, and they haven’t turned out to be very accurate. The Administrator has Congressional political constraints and is part of the aerospace old guard that had a sort of learned-helplessness about new aerospace endeavors. Falcon Heavy can absolutely be human rated. There’s also the possibility of LEO rendezvous between a Dragon launched on a Falcon 9 and a filled Falcon Heavy upper stage with a docking port on it.
- bryanlarsen 5y ago
  Falcon Heavy cannot be human rated under current NASA design guidelines. So NASA would have to change those guidelines to human rate Falcon Heavy. Which they should absolutely do -- being able to closely inspect returned boosters gives far better data than design guidelines based on computer models. That's the plan for Starship. It doesn't follow the NASA man rating design guidelines either, AFAIK. But SpaceX doesn't need NASA human rating to fly non-NASA personnel and have no immediate plans to fly NASA astronauts on Starship. By the time they do compete for a NASA human contract with Starship they expect to have enough flight data to meet NASA's standard of less than 1/500th of a chance of loss of mission using hard test data rather than computer modelling. Even Bolden has changed his tune now that he's retired and doesn't have to answer to Congress. He says that SLS should be cancelled. I wonder if Senator Shelby will change his tune after he retires? Somehow I doubt it.
  - panick21_ 5y ago
    Can you be more specific about what is strictly outside human rating? Nothing in Starship should be outside of human rating specifications. They have never done those for powered landings but its not outside of scope.
    - bryanlarsen 5y ago
      The most egregious is that Starship doesn't have a full envelope launch escape system.