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FTR_1077 t1_isrha70 wrote

Reply to comment by bambooboi in NASA outlines case for making sole-source SLS award to Boeing-Northrop joint venture by jeffsmith202

Falcón heavy is not human rated, and will never be. Also, SLS is 80% more powerful.. so no, it doesn't work.

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Shrike99 t1_isryk8x wrote

>Falcón heavy is not human rated, and will never be.

It could be if the desire was there. SpaceX originally planned to do it when they had a customer who wanted to fly on it, but after the customer changed their mind SpaceX no longer had any reason to do it.

If NASA asked SpaceX to crew-rate Falcon Heavy, it would be done. It would hardly the first time SpaceX changed their minds in order to meet NASA's requirements.

Also, the fact that Falcon 9 is crew rated, currently flying on a regular basis, and arguably the most reliable launch vehicle in history means Falcon Heavy is starting from a good basis, moreso than SLS I'd argue.

>SLS is 80% more powerful

In terms of raw thrust, sure. But it's also very inefficient, such that in terms of payload capability it's only around 25% more capable to TLI, and most of that is from the high efficiency upper stage. If you put a similar high efficiency stage on top of Falcon Heavy (traditionally the SLS's ICPS is proposed, but Centaur V would be even better) it actually gets pretty damn close. With propellant crossfeed in the mix you'd all but match it.

Such developments would take time and money, but would still likely be cheaper than SLS in the long run. However much like with crew-rating SpaceX would prefer to focus on Starship, and NASA currently show no interest in developing such capabilities, though the previous administrator did raise the possibility.

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nate-arizona909 t1_isudtni wrote

$3B per launch doesn’t work either, regardless of the paper performance.

SLS is really quite the accomplishment. A rocket too expensive to launch.

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seanflyon t1_isriane wrote

Falcon Heavy will be human rated if their is a customer to pay for it. SLS is years away from being ready to carry humans. Falcon Heavy could easily be ready to carry humans before SLS is ready to carry humans.

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FTR_1077 t1_isrj68m wrote

>Falcon Heavy will be human rated if their is a customer to pay for it.

Elon said that will never happen, SpaceX is betting on starship.

>SLS is years away from being ready to carry humans.

SLS is ready to carry humans right now, of course it needs to be tested first. But it is already human rated.

>Falcon Heavy could easily be ready to carry humans before SLS is ready to carry humans.

Again, Elon said that will never happen.. and regardless, it doesn't have enough power (remember the 80% mention before).

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seanflyon t1_isrnrgu wrote

> Elon said that will never happen

Do you have a source for that? Specifically that they would not do it for a paying customer? From what I recall they have said the opposite. You may have heard a statement that they don't think they will ever have a customer want to pay to human rate FH when Starship is better and cheaper.

> SLS is ready to carry humans right now

Either it is ready or it is not. It needs to be tested first and will not be ready to carry humans for a few years assuming everything goes according to plan. It would be ridiculously dangerous to put humans on an untested rocket, not to mention the capsule on top does not yet have a full life support system and the Artemis 1 launch will not have a working launch escape system.

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Apprehensive_Note248 t1_issetky wrote

I don't know how one can say it's ready for humans now, but needs testing first with a straight face. That is literally not being ready.

SLS apologists...

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MaltenesePhysics t1_isrl8jf wrote

FH will never be human rated, but I don’t consider SLS human rated. The ECLSS is disabled/missing for Artemis 1, something absolutely critical for Human Spaceflight. It’s ludicrous that there’s no ECLSS on mission 1 to shake out issues, but that’s another story. It’s like they’re begging for something to fail on A2, when they could’ve just tested on A1.

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Hussar_Regimeny t1_isrnaql wrote

> ECLSS

I should point out that the ECLSS has been tested extenstively on the ground already. Sending up with A1 will give little to no new data. The only way to stress test an ECLSS is to have humans aboard. Plus parts of it at the very least have been tested onboard the ISS

Plus it's not uncommon to not place the ECLSS on flights. DM-1 didn't have one and then DM-2 flew with humans and with the ECLSS for the first time. So this isn't the ludicrous action you think it is.

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MaltenesePhysics t1_isth0j0 wrote

That’s not true. DM-1 had its ECLSS installed and enabled. They ran into some issues with it during flight, even with no crew aboard. You can’t find unexpected issues with a system without having the system installed. It doesn’t make sense for them to not take the opportunity to test the entire system in deep space.

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