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Falcon Heavy is not designed for crew. Starship is but is still under development. On the other hand, this launched today. We can afford the extra cost, I ce

Falcon Heavy is not designed for crew. Starship is but is still under development. On the other hand, this launched today. We can afford the extra cost, I celebrate the success. Some day Starship will have its moment as well.

Thlom 4y ago
As far as I understand Starship can only reach LEO and requires refueling from several refueling missions while in orbit for longer missions. Great if spacex is able to pull it off, but it is years if not decades until they get there.
- szundi 4y ago
  Several refueling is actually much cheaper than having it launched in a single piece because of the "rocket equation", google it. It is a good thing.
  - tehbeard 4y ago
    downplaying the difficulties of on orbit refuelling. This isn't kerbal space program... Fluid's gonna fluid dynamics in a 0g environment...
    - cnlevy 4y ago
      Differential pressure + milli-g induced gravity using thrusters should help a lot. I bet it won't take more than 5 tries to do a full tank Starship transfer. And SpaceX iterates quickly
    - mlindner 4y ago
      > downplaying the difficulties of on orbit refuelling. Every single person I've heard say this hasn't given a reasonable reason why it's difficult other than "we've never done it before". Also on-orbit refueling has been done, just not with cryogenics. Additionally it's only been done in zero-G with bladders. A slight vehicle spin to settle tanks seems like it would be sufficient to feed some low speed pumps without bladders.
- randomsearch 4y ago
  Describing anything SpaceX are already working on as “decades out” seems a bit risky given their rapid successes!
- mlindner 4y ago
  Starship didn't even exist other than in the form of some slides and early test articles as of 3 years ago. Now it's a fully built vehicle with one almost completed pad and one pad in early construction, getting very close to launch. Predicting decades when it took them only 3 years to go from "nothing" to on the pad is a bit much.
TaylorAlexander 4y ago
On the other hand, by the time SLS launches a second time, Starship will probably have launched ten times. The launch cadence for SLS is terrible.
rblatz 4y ago
“Let’s be very honest, We don’t have a commercially available heavy-lift vehicle. The Falcon 9 Heavy may some day come about. It’s on the drawing board right now. SLS is real.” If in 2014, when this was said, NASA asked and funded SpaceX to human rate Heavy, they’d have launched already.
somat 4y ago
Not designed for crew does not mean much, there is nothing inherent about that rocket that means you can't put a crew capsule on it. hell, project mercury slapped one on an atlas icbm. The aprophical story was that the astronauts could feel the rocket seeking to fulfill it's ballistic missile targeting duties when the signal from the ground stations cut out momentarily. which I don't believe for a minute, but it does make for a good story.
- ddalex 4y ago
  > there is nothing inherent about that rocket that means you can't put a crew capsule on it But there is; gold standard for human rated missions is 98% reliability rate. This means testing every single component, and making sure that Product(Px) > 0.98 where Px is the probability failure of component x. This drives the cost up exponentially. E.g. if the rocket has Px = 0.99 and the crew capsule has Pcapsule = 0.99, then Psystem = 0.98, barely clearing the threshold. Falcon 9 had 3.5 failures out of 185 launches, giving it a Pfalcon9 = 0.98; PfalconHeavy then is,at most, 0.98^3 = 0.84, way too low to make it human-rateabale. The difference between Procket 0.84 and P0.99 is exponential cost.
  - pilsetnieks 4y ago
    0.98^3 is 0.94, not 0.84
    - ddalex 4y ago
      Of course, you are right and I am wrong - fat fingered the calculation. The point however still stands - every extra point of reliability costs 10x.
  - philipwhiuk 4y ago
    Prior to this launch SLS was 0/0. It's now 1/1. Falcon Heavy has never had a launch failure. It's 4/4 If you're arguing it's had a failure because it shares heritage then SLS was 133/135 before the launch which is worse and so shouldn't fly crew until it does way more than just one flight.
Denvercoder9 4y ago
> Falcon Heavy is not designed for crew. [..] On the other hand, this launched today. The Orion capsule launched today did not include the ECLSS system.
mlindner 4y ago
Falcon Heavy was not needed to be designed for crew, and the base rocket IS designed for crew. The only thing AFAIK that would make it "designed for crew" is a whole lot of NASA paperwork, and some throttling profiles to reduce peak accelerations.
- bumby 4y ago
  There’s a lot more for consideration. All that “NASA paperwork” covers things to ensure the design meets specific risk thresholds. For example, human-rated system usually are a no-go with a single point of failure that can cause a loss of crew. If that does exist, they either need to redesign or get everyone to agree to the new risk assessment.

Thlom 4y ago

As far as I understand Starship can only reach LEO and requires refueling from several refueling missions while in orbit for longer missions. Great if spacex is able to pull it off, but it is years if not decades until they get there.

szundi 4y ago
Several refueling is actually much cheaper than having it launched in a single piece because of the "rocket equation", google it. It is a good thing.
- tehbeard 4y ago
  downplaying the difficulties of on orbit refuelling. This isn't kerbal space program... Fluid's gonna fluid dynamics in a 0g environment...
  - cnlevy 4y ago
    Differential pressure + milli-g induced gravity using thrusters should help a lot. I bet it won't take more than 5 tries to do a full tank Starship transfer. And SpaceX iterates quickly
  - mlindner 4y ago
    > downplaying the difficulties of on orbit refuelling. Every single person I've heard say this hasn't given a reasonable reason why it's difficult other than "we've never done it before". Also on-orbit refueling has been done, just not with cryogenics. Additionally it's only been done in zero-G with bladders. A slight vehicle spin to settle tanks seems like it would be sufficient to feed some low speed pumps without bladders.
randomsearch 4y ago
Describing anything SpaceX are already working on as “decades out” seems a bit risky given their rapid successes!
mlindner 4y ago
Starship didn't even exist other than in the form of some slides and early test articles as of 3 years ago. Now it's a fully built vehicle with one almost completed pad and one pad in early construction, getting very close to launch. Predicting decades when it took them only 3 years to go from "nothing" to on the pad is a bit much.

TaylorAlexander 4y ago

On the other hand, by the time SLS launches a second time, Starship will probably have launched ten times. The launch cadence for SLS is terrible.

rblatz 4y ago

“Let’s be very honest, We don’t have a commercially available heavy-lift vehicle. The Falcon 9 Heavy may some day come about. It’s on the drawing board right now. SLS is real.” If in 2014, when this was said, NASA asked and funded SpaceX to human rate Heavy, they’d have launched already.

somat 4y ago

Not designed for crew does not mean much, there is nothing inherent about that rocket that means you can't put a crew capsule on it. hell, project mercury slapped one on an atlas icbm. The aprophical story was that the astronauts could feel the rocket seeking to fulfill it's ballistic missile targeting duties when the signal from the ground stations cut out momentarily. which I don't believe for a minute, but it does make for a good story.

ddalex 4y ago
> there is nothing inherent about that rocket that means you can't put a crew capsule on it But there is; gold standard for human rated missions is 98% reliability rate. This means testing every single component, and making sure that Product(Px) > 0.98 where Px is the probability failure of component x. This drives the cost up exponentially. E.g. if the rocket has Px = 0.99 and the crew capsule has Pcapsule = 0.99, then Psystem = 0.98, barely clearing the threshold. Falcon 9 had 3.5 failures out of 185 launches, giving it a Pfalcon9 = 0.98; PfalconHeavy then is,at most, 0.98^3 = 0.84, way too low to make it human-rateabale. The difference between Procket 0.84 and P0.99 is exponential cost.
- pilsetnieks 4y ago
  0.98^3 is 0.94, not 0.84
  - ddalex 4y ago
    Of course, you are right and I am wrong - fat fingered the calculation. The point however still stands - every extra point of reliability costs 10x.
- philipwhiuk 4y ago
  Prior to this launch SLS was 0/0. It's now 1/1. Falcon Heavy has never had a launch failure. It's 4/4 If you're arguing it's had a failure because it shares heritage then SLS was 133/135 before the launch which is worse and so shouldn't fly crew until it does way more than just one flight.

Denvercoder9 4y ago

> Falcon Heavy is not designed for crew. [..] On the other hand, this launched today. The Orion capsule launched today did not include the ECLSS system.

mlindner 4y ago

Falcon Heavy was not needed to be designed for crew, and the base rocket IS designed for crew. The only thing AFAIK that would make it "designed for crew" is a whole lot of NASA paperwork, and some throttling profiles to reduce peak accelerations.

bumby 4y ago
There’s a lot more for consideration. All that “NASA paperwork” covers things to ensure the design meets specific risk thresholds. For example, human-rated system usually are a no-go with a single point of failure that can cause a loss of crew. If that does exist, they either need to redesign or get everyone to agree to the new risk assessment.