Saturn V VS SLS

[Nibb31]

Just a quick point to make, NASA estimates that they can get 4 or 5 SLS launches a year

Production facilities and logistics chains are sized for 1 SLS launch per year, with a possibility of extending to 2.

But the real bottleneck is payloads. Heavy payloads typically cost more than smaller ones. NASA can't afford a 100-ton mission every year. We will be lucky if we get an SLS every 2 years.

[fredinno]

Production facilities and logistics chains are sized for 1 SLS launch per year, with a possibility of extending to 2.

But the real bottleneck is payloads. Heavy payloads typically cost more than smaller ones. NASA can't afford a 100-ton mission every year. We will be lucky if we get an SLS every 2 years.

No, it's sized for 1-2 a year, extensionable to 4 a year.

[Bill Phil]

Can either of you back up your claims?

[Nibb31]

"The Vertical Weld Center, Gore Weld Tool and Circumferential Dome Weld Tool that are there now could make two SLS core stage structures a year at most"

http://spacenews.com/36012tooling-processes-coming-together-for-affordable-space-launch-system/

"NASA officials are claiming that launches will cost about $500 to $700 million each. That sounds fairly reasonable given the massive payload SLS would be able to place into orbit. And you might think, well, in a good year NASA might be able to launch two of them? Wrong.

The $500 to $700 million figure might be the marginal cost of the launch, not including all the additional fixed costs of the infrastructure and program (the $3 billion per year figure). Just like the shuttle program cost about $3 billion per year whether NASA launched once or five times."

http://www.parabolicarc.com/2014/04/12/sad-cost-sls-deep-space-operations/

"Once SLS has completed its political role with EM-1 and EM-2, a mix of cargo and crewed missions are expected, launching at least once a year. SLS is currently projected to have the capability of launching once every six months."

http://www.nasaspaceflight.com/2014/02/sls-launch-rate-repetitive-cadence-gerstenmaier/

And then there are the actual launches that are manifested: EM-1 in 2017, and EM-2 in 2021 (at best). There are no other flights manifested for 2022, 2023, or 2024, which makes any predictions of "one flight per year" bogus. Nobody is seriously expecting SLS to ever fly more than twice a year.

Edited September 6, 2015 by Nibb31

[fredinno]

Production facilities and logistics chains are sized for 1 SLS launch per year, with a possibility of extending to 2.

But the real bottleneck is payloads. Heavy payloads typically cost more than smaller ones. NASA can't afford a 100-ton mission every year. We will be lucky if we get an SLS every 2 years.

Can either of you back up your claims?

Here, http://m.space.com/17556-giant-nasa-rocket-space-launch-cost.html.

It actually says 2 per year, but I used a more conservative estimate, as NASA probably won't meet their targets, like so many times before.

[Bill Phil]

Fredinno, you're claiming its extendable to 4 per year, and you've used outdated info that doesn't really back that up. The real bottleneck is Michoud, which can only build a certain number of cores per year. We would need to build another similar sized facility to double the rate of production. And that's not counting the amount of time it would take to get the launch pads flight ready again.

[fredinno]

It would never reach that level of production anyways, so I don't really believe the extensionable number is very relevent anyways. Either way, this is getting off topic.

[cantab]

Saturn V.

It actually flew, the SLS remains an ongoing project.

It had a compelling payload, possibly the most compelling spacecraft in all of history, Apollo. SLS has nothing really. Re-enacting Apollo 8? Fun, but hardly groundbreaking. Visiting a small asteroid that's been dragged into lunar orbit? Kind of neat, but wouldn't it be better to put the rock in LEO? Anything else for SLS is somewhat hypothetical. I can't say why America won't go to Mars (because Squad sez NO POLITICS GUIS!). Hubble 2 or ISS2 would both be great candidates for SLS launches benefiting from its wide payload fairing but there's basically no work on those ideas.

The Saturn V was pretty much the rocket it was meant to be. It helped that it had a clearly defined goal of course. The SLS Block I by contrast is a half-baked version. NASA are working on flying it with Shuttle SRBs and an upper stage nicked off the Delta IV, while all along they want different boosters and upper stage for the "real" SLS. And NASA tried the same route with the Shuttle and the intended configuration never flew, it got stuck with the solid boosters forever.

As for Falcon Heavy, it's in the same class as SLS Block 1 and I expect it to fly. If R&D was directed into making lightweight spacecraft I think it could run a Moon mission and it certainly could if orbital assembly was used.

[Kibble]

Kind of neat, but wouldn't it be better to put the rock in LEO?

Purposely directing an asteroid to come within a thousand km of Earth's surface sounds like a very bad idea!

As for Falcon Heavy, it's in the same class as SLS Block 1 and I expect it to fly. If R&D was directed into making lightweight spacecraft I think it could run a Moon mission and it certainly could if orbital assembly was used.

Minotaur 1 could run a Moon mission if orbital assembly was used.

[cantab]

Minotaur 1 could run a Moon mission if orbital assembly was used.

OK, technically true, but I assumed the rider "in a reasonable number of launches" was implied.

[Kibble]

OK, technically true, but I assumed the rider "in a reasonable number of launches" was implied.

Sorry I was actually trying to make the point that orbital assembly is rarely very practical x.x

[Sampa]

Can either of you back up your claims?

I actually can...my air and space magazines

[Bill Phil]

I actually can...my air and space magazines

I was not referring to you.

- - - Updated - - -

Sorry I was actually trying to make the point that orbital assembly is rarely very practical x.x

But you succeeded in doing the opposite...

It's very practical. Once in LEO, the energy required to get to other places isn't nearly as much of a mountain as the trip to orbit. It becomes even more practical if you use resources in space.

[architeuthis]

Nobody is seriously expecting SLS to ever fly more than twice a year.

I recently attended the AIAA Space 2015 conference in Pasadena. I watched a number of interesting presentations. While I was there I got the distinct sense that NASA's manned mars vision is starting to become more concrete. The Evolvable Mars Campaign architecture, as it's called, is planned to send 4 people to Phobos in 2035 or so, using SEP/space storable hypergolic hybrid propulsion on a reusable vehicle. Manned missions to Mars surface would follow shortly afterwards. People seem to be rallying around this idea for several reasons:

• reuse->long term sustainability, better than flags & footprints Apollo on steroids DRA5
  
• nearly all of the required technology is high TRL, low development risk
  
• no more than 2 SLS cores per year
  
• could fit in NASA's current budget if indexed for inflation
  
• don't need to fully commit to the strategy till early 2020's; before then much of the dev work is synergistic with current missions/flexible path
  

My impression is that there is alot support for this coming from the NASA GRC and KSC centers. At the Satellite Servicing Capabilities Office at GSFC, where I currently work, we're developing related technologies (on-orbit autonomous servicing, hypergolic and xenon refueling).

[The Yellow Dart]

I recently attended the AIAA Space 2015 conference in Pasadena. I watched a number of interesting presentations. While I was there I got the distinct sense that NASA's manned mars vision is starting to become more concrete. The Evolvable Mars Campaign architecture, as it's called, is planned to send 4 people to Phobos in 2035 or so, using SEP/space storable hypergolic hybrid propulsion on a reusable vehicle. Manned missions to Mars surface would follow shortly afterwards. People seem to be rallying around this idea for several reasons:

• reuse->long term sustainability, better than flags & footprints Apollo on steroids DRA5
  
• nearly all of the required technology is high TRL, low development risk
  
• no more than 2 SLS cores per year
  
• could fit in NASA's current budget if indexed for inflation
  
• don't need to fully commit to the strategy till early 2020's; before then much of the dev work is synergistic with current missions/flexible path
  

My impression is that there is alot support for this coming from the NASA GRC and KSC centers. At the Satellite Servicing Capabilities Office at GSFC, where I currently work, we're developing related technologies (on-orbit autonomous servicing, hypergolic and xenon refueling).

I find this post very exciting. Thanks for sharing.

And I'd have to choose SLS because it seems like it will be more flexible in terms of payloads with the different blocks.

[Nibb31]

Purposely directing an asteroid to come within a thousand km of Earth's surface sounds like a very bad idea!

The size of the sort of asteroid that would could effectively redirect makes it no threat at all.

[Rath]

But can you convince the politicians?

[fredinno]

But people, including congressmen (who fund it BTW) would flip their .....

So yeah, ARM should go into lunar orbit, and therefore, also needs SLS to 'explore' it, to let people feel safe, if nothing else.

[cryogen]

Visiting a small asteroid that's been dragged into lunar orbit? Kind of neat, but wouldn't it be better to put the rock in LEO?

The asteroids are in sun orbit, so it takes far less delta-v to move them to a high earth orbit (like EML1), than a low one.

In the reference concepts, the propulsive delta-v's are on the order of 300 m/s -- i.e. 1,000 tonnes asteroid mass, 10 tons Xe propellant, and 3,000s Isp. (The NEA v_inf's are higher, but most of the delta-v comes from a lunar gravity assist). A low-thrust spiral to LEO would add about 6 km/s, increasing the total delta-v by a factor of 20. That's probably not realistic.

http://www.kiss.caltech.edu/study/asteroid/papers/near.pdf

Edited September 7, 2015 by cryogen

[mellojoe]

Saturn V had about 4 to 4.5% of the federal budget behind it. SLS has less than 0.5%. Which means, of course, cost savings will have to play a major factor. Which saddens the engineer in me, but excites the financier in me. SLS will never get the nation behind it like the Saturn V did. Simple in its idea, massively complex to actually achieve, and in a time when NASA became a beacon to the nation. Saturn V will always win. But, we are so close to having another major moment in time. I don't know if it will be SLS that does this or one of the other technologies. Look how the world reacted to the New Horizons mission. To the Mars Curiosity Rover a few years back. We are on the verge of making space science a national wonder again.

I want SLS to be amazing. I want Falcon Heavy to be amazing. I want Sierra Nevada to actually make their Dream Chaser. So many things I really, really want ...

[Dkmdlb]

Saturn V had about 4 to 4.5% of the federal budget behind it. SLS has less than 0.5%. Which means, of course, cost savings will have to play a major factor.

That's not really a good way of measuring. The federal budget isn't some objective unwavering standard by which to measure cost. And it's not really true anyway. NASA had that size budget, but that money was split between several projects, not just the rocket. A more appropriate measurement would be dollars adjusted for inflation. Wikipedia lists the "project cost" as $41.3 billion dollars adjusted for inflation. And that includes all the launches, not just development.

The SLS is projected to cost ~$10 billion through 2018 according to Wikipedia. At that link there is a link to a NASA document which estimated the cost of the SLS through the first 4 launches at $41 billion.

Depending on how you want to measure the costs, SLS is sort of in line with Saturn. It's definitely not 1/8 as expensive.