Jump to content

[New] Space Launch System / Orion Discussion Thread


Recommended Posts

The benefit is keeping people in or training new ones into the sector.  The cost has always been about not letting the capability whither; and we are actually seeing the problems of inherent knowledge evaporation.  The folks that could and did build the rockets in the old days are gone and the new ones are having to figure out (again) how all of that works. 

Not everything is in the manuals.

Link to comment
Share on other sites

1 hour ago, Beccab said:

The problem of SLS is definitely not money, on recent years congress allocated to it more money than NASA requested and is already twice over budget. SLS like that because it was designed by congressmen (in general design, type of propulsion and even payload target for whatever reason) and built using outdated types of contracts (cost plus to build a SOFI tank, really?) to benefit legacy aerospace contractors. It's a 20th century rocket, no different than the dozens of shuttle derived launch vehicles that were designed since the RS-25 started static fires but with the worse of all problems the modern aerospace industry has

So a redesign would be best?

Link to comment
Share on other sites

31 minutes ago, kerbiloid said:

And that's also why expendable rockets are better than reusable ones.

By making them, you train.

Not if you cant afford to build 2 before the guy in charge retires. 

Reusables at least get more capability over their lifespan. Build the same number as you would build expendables, you get the same benifits, but also get to fly an order of magnitude more.

Link to comment
Share on other sites

2 hours ago, kerbiloid said:

And that's also why expendable rockets are better than reusable ones.

By making them, you train.

Not really. You'd need to have a high cadence, and you'd have to be willing to alter the design with what you learned from the last launch. SpaceX clearly did a bit of that with F9, but when was the last design change on Atlas V, or Delta IVH, etc? Any change in SLS would have been cast in stone years ago (Block 1B, Block 2).

Link to comment
Share on other sites

2 hours ago, RCgothic said:

Also if you don't get the rocket back to analyse, your ability to update is limited to what you can assess from telemetry.

This is quite true, almost all the Falcon 9 iteration has been on the booster, stage 2—has it changed at all?

Link to comment
Share on other sites

6 hours ago, RCgothic said:

Also if you don't get the rocket back to analyse, your ability to update is limited to what you can assess from telemetry.

All rockets but Falcon have been developed without getting them back.

And the smoking remains of a failed rocket is absolutely same for both expendable and reusable rockets to investigate this and update it.

While a normally working rocket is happy with the telemetry.

Link to comment
Share on other sites

1 hour ago, kerbiloid said:

All rockets but Falcon have been developed without getting them back.

And iteration is slow or nonexistent.

Look at Soyuz, just capacity to LEO (forgive any wrong numbers, this is straight wiki):

Soyuz 11A511 (1966-1975)                                               6400kg

Soyuz-L 11A511L (1970-1971)                                       5500kg

Soyuz-M 11A511M (1971-1976)                                   6600kg

Soyuz-U 11A511U (1973-2017)                                     6900kg

Soyuz-U2 11A511U2/11A511K (1982-1995)       7050kg

Soyuz-FG 11A511U-FG (2001-2019)                         7800kg

Soyuz-2 14A14 (2006-today)                                           8200kg

 

Fantastic launch vehicle. In almost 60 years only 7 major iterations. So 40 years from the first to Soyuz-2, with a 128%. difference in payload.

Falcon 9 will have been flying 10 years as of Oct 2022.

Payload evolution to LEO—expended (from space launch report, also, stupid Elon name changes block, version, etc):

Block 1 (2010-2013):                                                      9000kg

Block 2 aka V 1.1 (2013-2015):                                13150kg

Block 3 aka V 1.2 (2015-2018):                                17400kg

Block 5 (2013-2015):                                                     22800kg

Change in payload 253% in <10 years. Note the above are major changes, but we know that many boosters were very slightly different from each other testing stuff out.

Rockets like Atlas, Delta, etc were not really changed at all.

Link to comment
Share on other sites

3 hours ago, tater said:

And iteration is slow or nonexistent.

Look at Soyuz, just capacity to LEO (forgive any wrong numbers, this is straight wiki):

Soyuz 11A511 (1966-1975)                                               6400kg

Soyuz-L 11A511L (1970-1971)                                       5500kg

Soyuz-M 11A511M (1971-1976)                                   6600kg

Soyuz-U 11A511U (1973-2017)                                     6900kg

Soyuz-U2 11A511U2/11A511K (1982-1995)       7050kg

Soyuz-FG 11A511U-FG (2001-2019)                         7800kg

Soyuz-2 14A14 (2006-today)                                           8200kg

 

Fantastic launch vehicle. In almost 60 years only 7 major iterations. So 40 years from the first to Soyuz-2, with a 128%. difference in payload.

Falcon 9 will have been flying 10 years as of Oct 2022.

Payload evolution to LEO—expended (from space launch report, also, stupid Elon name changes block, version, etc):

Block 1 (2010-2013):                                                      9000kg

Block 2 aka V 1.1 (2013-2015):                                13150kg

Block 3 aka V 1.2 (2015-2018):                                17400kg

Block 5 (2013-2015):                                                     22800kg

Change in payload 253% in <10 years. Note the above are major changes, but we know that many boosters were very slightly different from each other testing stuff out.

Rockets like Atlas, Delta, etc were not really changed at all.

I think this portion of the discussion is flawed. This was/is caused by institutional and financial problems, not the rocket being expendable.

Reusability does help solve those financial problems and thus I think it could be said that reusability is necessary for rapid iteration, but from a financial perspective- I still haven't seen any evidence that bringing back Falcon 9 has improved the design process over that of an expendable rocket.

------

One problem though is that it is hard to compare the development of Falcon 9 and the development of Soyuz because one is reusable and one isn't. It's obvious that Falcon 9 is going to have a lot of improvements, it is a freaking reusable rocket. In contrast, Soyuz won't see major improvements, not because of a lack of data, but because there simply aren't many improvements to be made.

To use a metaphor, a train is going to see a lot of improvements over 100 years vs. the horse drawn cart in 100 years, but that's because the train is a train and has room for improvement. And while yes, the train is objectively better than the horse drawn cart, just because the horse drawn cart couldn't improve in the same way the train did, did that mean the "development process" that gave us the horse drawn cart was "useless" or "backwards" or even "bad"?

I would say no, because the horse drawn cart helped drive societal development for the past 3500 years, development which enabled the train to exist in the first place.

So to sum it up, if you want to build a reusable rocket, reusability is better, but if you don't, then non-reusability can be just as "good". Part of the problem with criticisms of *everybody else but SpaceX* is that the criticizers are expecting everyone else to do what SpaceX is doing. If I was CASIC and I was criticizing SpaceX for not trying to compete for weapons contracts to fund Starship, that could be a logically valid criticism, but SpaceX is SpaceX- they are where they are and they do their thing- so is it really justified and sensible to hold them to my standard?

That said, this only goes for organizations like Roscosmos/RSC Energia and JAXA/Mitsubishi Heavy Industries with rockets that actually function. SLS is it's own nightmare (billions of dollars to send astronauts through the Van Allen belts multiple times), so I think criticism of it and the processes that led to it are justified.

Edited by SunlitZelkova
Link to comment
Share on other sites

1 hour ago, SunlitZelkova said:

Reusability does help solve those financial problems and thus I think it could be said that reusability is necessary for rapid iteration, but from a financial perspective- I still haven't seen any evidence that bringing back Falcon 9 has improved the design process over that of an expendable rocket.

Fair, I wasn't suggesting that reuse was required for iteration, if anything, reuse being new needed iteration to happen.

The Shuttle was cool, but the improvements were so incremental (mass reduction, electronics, etc) that we never saw a "next gen" Shuttle, sadly—a missed opportunity.

Link to comment
Share on other sites

9 hours ago, JoeSchmuckatelli said:
9 hours ago, kerbiloid said:

All rockets but Falcon and SN15

FTFY

Did SN15 reach the LEO, or is it just a lowspeed hopper without the SH booster?

2 km/s or 8 km/s?

In this case, Blue Origins also can into space.

7 hours ago, tater said:

Look at Soyuz, just capacity to LEO (forgive any wrong numbers, this is straight wiki):
<...>
Fantastic launch vehicle. In almost 60 years only 7 major iterations. So 40 years from the first to Soyuz-2, with a 128%. difference in payload.

Just an established product, using the existing assemble and launch complex.
Finally they made it carry ~3% of launch mass to LEO, originally it was less.

Protons and Cyclons have delivered several times more cargo to LEO than Soyuz, just they are not so famous due to secrecy.

7 hours ago, tater said:

Falcon 9 will have been flying 10 years as of Oct 2022.

Payload evolution to LEO—expended (from space launch report, also, stupid Elon name changes block, version, etc):

Block 1 (2010-2013):                                                      9000kg

Block 2 aka V 1.1 (2013-2015):                                13150kg

Block 3 aka V 1.2 (2015-2018):                                17400kg

Block 5 (2013-2015):                                                     22800kg

Change in payload 253% in <10 years.

Finally it got as capable as Proton.

So, originally it had a twice worse performance than it could.

Proton had originally ~18 t, then reached ~22 t. That's because it was designed properly from the beginning.

***

The launch cost is not defined by the rocket cost, 

A plane has a several ten thousands flights lifespan and it doesn't need a reassembly between the flights to test every part and sort out spent parts.
All it needs is a quick watch and refuel. It takes hours.

How long does it take between two flights of the same Falcon instance?
Isn't this a work of several hundreds of qualified specialists for qualified money? 
Don't they check and certify every part like if it was just produced?
See Shuttle for example.

When an uncrewed rocket can be launched ten times, this means that every launch decreases her reliability enough to doubt in the eleventh one (even if it is crewless).
In turn, this means that you can make only one or two launches with crewed or valuable cargo, while the rest ones are for easy-come-easy-go payload like Starlinks and Cubesats.

So, a reusable rocket makes sense when it :
e
ither can fly 100 times with total check every 10th flight or better never;
or is to carry  payload cheaper than the rocket itself (or the payload is mass-produced), and nobody spends money on the rocket full check;
or is so large and complicated, that only ten launches are required, and it's easier than build it every time.

SS/SH currently looks not more reliable than Falcon is.
Its lifespan unlikely can reach more than several flights, its payload is either not much greater than Falcon Heavy's one, or vice versa is too great to launch cubesats.

So, while SS/SH looks more fancy, SLS is supporting the existing industry, the ICBM production, the factory personnel business and qualification, and is probably enough to deliver a half of the Moon expedition to the LOP-G and back without flying circus of elliptic orbit refuelling and so on.

Edited by kerbiloid
Link to comment
Share on other sites

12 minutes ago, kerbiloid said:

Proton had originally ~18 t, then reached ~22 t. That's because it was designed properly from the beginning.

Falcon 9 was designed to launch Dragon to ISS. It more than doubled that in 3 years—and is reusable.

Link to comment
Share on other sites

8 hours ago, kerbiloid said:

As a Starlink carrier. They don't launch a crew by its eighth flight.

Not yet.

8 hours ago, kerbiloid said:

While a billion expensive sat makes even a new Falcon cost negligible.

That's why the sat companies don't care about launch costs and buy more expensive ULA launches... oh, wait.

Link to comment
Share on other sites

7 minutes ago, tater said:

That's why the sat companies don't care about launch costs and buy more expensive ULA launches... oh, wait.

Same for the DoD, zero need for anything other than ula - that is why NSSL launches are 100% ULA and 0% SpaceX... oh wait 

Link to comment
Share on other sites

5 minutes ago, kerbiloid said:

What's the difference between the 10th and the 11th flights?

No idea. The point is they build data on booster reuse, then NASA can decide what they want for crew launches (assuming they save money by doing so).

Link to comment
Share on other sites

33 minutes ago, JoeSchmuckatelli said:

NASA? 

Without NASA is the craft lifespan unlimited?

Or its reliability is decreasing every flight and requires a part replacement, making it cheaper to replace the whole rocket by the tens flight?

Link to comment
Share on other sites

23 minutes ago, kerbiloid said:

Without NASA is the craft lifespan unlimited?

Or its reliability is decreasing every flight and requires a part replacement, making it cheaper to replace the whole rocket by the tens flight?

Booster reuse is new, so you'd want to characterize how the vehicle has dealt with repeated launch/entry regimes, and whatever engine refurb might be required at some point. What's odd about gathering the data, exactly, particularly for crew flights?

There's nothing magical here, they are gathering data.

Edited by tater
Link to comment
Share on other sites

13 minutes ago, tater said:

There's nothing magical here, they are gathering data.

There is nothing magical in the hardware depreciation.
Any hardware is designed for a known presumed number of rounds, and the most affected parts are tested on ground.

Any plane has a prototype to torture until death.

So, they can gather data if the rocket can survive 5 flights or 15, but not 10 or 100.

Link to comment
Share on other sites

12 hours ago, kerbiloid said:

A plane has a several ten thousands flights lifespan and it doesn't need a reassembly between the flights to test every part and sort out spent parts.
All it needs is a quick watch and refuel. It takes hours.

How long does it take between two flights of the same Falcon instance?
Isn't this a work of several hundreds of qualified specialists for qualified money? 
Don't they check and certify every part like if it was just produced?
See Shuttle for example.

Nope, they don't disassemble and recertify and reassemble each Falcon 9 booster between flights. That's nonsense. There is inspection, yes -- mostly weld x-rays and the like -- but there is virtually no refurbishment.

SpaceX currently has a fleet of 18 boosters. To achieve 50 launches in 2022 (more than the total number of successful orbital launches by the entire United States in 2021), they would only need to fly each booster 2-3 times, meaning that there is no need for them to shorten turnaround time to something lower than 4-6 months. That's just business.

To your point about planes: commercial aircraft receive an inspection that goes over hundreds of individual points between each flight. And then they receive a 6,000-man-hour "C check" inspection and refurbishment every 20-24 months, not dissimilar to what a Falcon 9 will receive after every ten flights, which (with the demonstrated minimum turnaround of 2 months) is approximately the same timescale. 

12 hours ago, kerbiloid said:

When an uncrewed rocket can be launched ten times, this means that every launch decreases her reliability enough to doubt in the eleventh one (even if it is crewless).
In turn, this means that you can make only one or two launches with crewed or valuable cargo, while the rest ones are for easy-come-easy-go payload like Starlinks and Cubesats.

No, that is not how vehicle reliability works. By that logic, every month of flight by a commercial airliner decreases her reliability enough to make them unsafe even for cargo by the 20-month mark, so therefore a commercial airliner should only fly 2-4 months with crew and carry cargo for the rest of the period before the next C check.  

12 hours ago, kerbiloid said:

SS/SH currently looks not more reliable than Falcon is.

And this analysis is based on...what exactly?

12 hours ago, kerbiloid said:

Its lifespan unlikely can reach more than several flights

I'm assuming this is some kind of heuristic...

12 hours ago, kerbiloid said:

its payload is either not much greater than Falcon Heavy's one

Ah, yes. 150 tonnes is not much greater than 68 tonnes.

Even if an individual Starship could not be flown more than 5 times, half the demonstrated reliability of Falcon 9, that would still be a payload capacity of 750 tonnes, giving a single Starship more than ten times the payload to orbit of a single Falcon 9 second stage.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...