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New video: What Scientists really think of Starship will blow your mind

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#1 Masonry00

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Posted 06 August 2022 - 01:37 AM

Interesting new video predicting a bright future for new space telescopes:

 

 

https://www.youtube....h?v=4oVwDLjlEaU

 

 


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#2 matt_astro_tx

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Posted 06 August 2022 - 04:22 AM

Good video.  My mind wasn't blown though.  I look forward to seeing "possible" get redefined with starship (and SLS). 


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#3 Kfrank

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Posted 06 August 2022 - 12:00 PM

I make it a point to ignore ANY internet pronouncement that promises to "blow my mind".  Also those which start out "I'm a ******** (fill in your favorite occupation here) and this is what I do/recommend".



#4 Masonry00

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Posted 07 August 2022 - 12:48 AM

I make it a point to ignore ANY internet pronouncement that promises to "blow my mind".  Also those which start out "I'm a ******** (fill in your favorite occupation here) and this is what I do/recommend".

 

Boring!



#5 JimMo

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Posted 09 August 2022 - 03:33 PM

Sorry, mind not blown.

 

SpaceX has a whole lot to prove if they want to refuel Starships in orbit. They'll have to do that in order to get it to the Moon to use as a lander. 

 

What I'd like to know is why is the SLS more powerful that the Saturn V but not taking a lander to the Moon like Apollo did?

 

There is no way they land on the Moon for at least a few more years yet, certainly not in 2024 or 2025.



#6 matt_astro_tx

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Posted Yesterday, 01:02 PM

What I'd like to know is why is the SLS more powerful that the Saturn V but not taking a lander to the Moon like Apollo did?

I believe it's the architecture.  SLS is two stage to orbit vs. the Saturn being 3 stages.  Well, SLS is 3 stages if you count the SRBs being stage 1.  Anyway, I don't think the upper stage of SLS is powerful enough to perform a TLI with a large a payload as Saturn carried.


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#7 JimMo

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Posted Yesterday, 05:29 PM

I believe it's the architecture.  SLS is two stage to orbit vs. the Saturn being 3 stages.  Well, SLS is 3 stages if you count the SRBs being stage 1.  Anyway, I don't think the upper stage of SLS is powerful enough to perform a TLI with a large a payload as Saturn carried.

Hi Matt, well, I can't wrap my head around this. The SLS is more powerful, but can't lift as much to the Moon as the Saturn V? Will future upgrades be able to lift more and lift what? 



#8 Masonry00

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Posted Yesterday, 05:59 PM

 

SpaceX has a whole lot to prove if they want to refuel Starships in orbit. They'll have to do that in order to get it to the Moon to use as a lander. 

 

What I'd like to know is why is the SLS more powerful that the Saturn V but not taking a lander to the Moon like Apollo did?

 

There is no way they land on the Moon for at least a few more years yet, certainly not in 2024 or 2025.

Starship is about reusability in order to keep costs affordable. Leaving millions of dollars worth of hardware on the moon is not economical. Starship avoids one-time use hardware. The goal is to be able to re-fuel it and go again, like an airplane does. Imagine how expensive an airline ticket would be if, after they landed, they had to leave the plane there and build a new one for the next flight!

 

Apollo was designed to be used one time and that was it. It was too expensive to do on a regular basis. Even the Space Shuttle cost an insane amount and months to refurbish after each flight. SpaceX is designing Starship to be able to refuel and re-launch hours after landing back on earth. Starship will be able to launch more tonnage into orbit or to other worlds (NASA has the moon as the first scheduled flight beyond earth orbit) for a tiny fraction of the cost it would take with a Saturn.


Edited by Masonry00, Yesterday, 06:02 PM.


#9 matt_astro_tx

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Posted Today, 03:51 AM

Hi Matt, well, I can't wrap my head around this. The SLS is more powerful, but can't lift as much to the Moon as the Saturn V? Will future upgrades be able to lift more and lift what? 

I dug into this some more and found this article that states the following figures as given by the SLS contractors.

 

SLS will have an "injected mass" of 143 tons to LEO, or 315klbs (For the Block 2 variant)

Saturn V had a mass of 135 tons to LEO, or 297klbs

 

This is somewhat misleading however as these figures include the upper stages and their fuel.  The real proof is in mass to trans-lunar injection, or TLI.

 

SLS Block 1 will have a TLI mass of 26 tons, or 57klbs

SLS Block 1B will have a TLI mass of 37 tons, or 81klbs

SLS Block 2 will have a TLI mass of 45 tons, or 99klbs

The Saturn V had a TLI mass of 48 tons, or 105klbs

 

So why won't SLS meet the performance of the Saturn V?  As I suspected, the key is the upper stage.  

 

The SLS Block 1 and 1B will use a single RL10 engine for the upper stage, which provides 25klbs of thrust in vacuum.

The Saturn V used a single J2 engine for its third stage which provided 232klbs of thrust in vacuum.

 

Yes that's right, the upper stage of the Saturn V had nearly 10 times the performance of the SLS Block 1's upper stage.

 

The true value of the SLS doesn't occur until the Block 2 variant comes online.  THAT rocket will use four upgraded RL10 engines in its upper stage, producing a combined total of 97klbs of thrust.  Better, but still less than half of the Saturn V.  I should point out that the other improvements in Block 2 are the addition of a fifth engine to the first stage and improvements to the SRBs.  These changes in concert with the four-engine second stage are what will get SLS to 99klbs TLI.

 

Its difficult to draw a straight line of comparison between the two vehicles, because they have different architectures.  The Saturn V was entirely liquid fueled while the SLS is a combination of solid fuel SRBs and liquid fueled engines.  The SRBs provide the bulk of the liftoff thrust (3Mlbs each) which pushes the SLS past the Saturn V in terms of total thrust at liftoff.  (Hence the moniker, "most powerful rocket ever launched.")  But in the end the upper stage performance is what pushes Saturn V past SLS in flights beyond earth orbit.

 

Let's face it, "Upper stage performance" isn't as sexy as "World's most powerful rocket."  And NASA needs positive advertisement for their vehicle that's 6 years late.  As was said elsewhere Congress mandated the use of proven shuttle hardware, which really handicapped the design before the program even started.  For what its worth, I think they built the best rocket they could with the pieces they were given.

 

I learned a lot in researching this.  I hope that answers your question.


Edited by matt_astro_tx, Today, 06:44 AM.



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