Author Topic: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars  (Read 86382 times)

Offline meiza

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Re: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars
« Reply #360 on: 04/13/2008 06:44 PM »
I'd classify as heavy lift something that is purpose-built and useless for satellite launches. So perhaps anything over 20-30 t to LEO or 10-15 t to GTO.
This (among other things) forces it to have a low launch rate and thus a high fixed proportion of the costs. It also ties the architecture down to that single launcher since other rockets can't help as they are too small.

Offline clongton

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Re: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars
« Reply #361 on: 04/13/2008 06:48 PM »
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mikers - 13/4/2008  5:44 AM

Equating 'heavy lift' to "100 metric tons to LEO" is entirely arbitrary and absurd.;
Back in the day when these terms were first defined and used:
Redstone didn't apply - it was a temporary "lift" - period.
Atlas and Titan launch vehicles were considered light lift
Saturn-1B was considered light lift with the ability to put 15.3mT into LEO
Saturn-V was considered heavy lift with the ability to put 110.6mT into LEO
We designed several, but didn't build, any medium lift launchers - we didn't have time.
Von Braun himself referred to heavy lift as being at the 100mT mark. I never heard the term "medium lift" used hardly at all, and "light lift" used rarely and only in a transitory sense.

It was only after Shuttle began flying that the terms began to be used all the time and people began to literally redefine the terms to, in my opinion, make things sound like they were better than they actually were. Suddenly, Shuttle became heavy lift. Von Braun would roll over in his grave if he could hear that.

Before Apollo, all we really had were converted IRBMs & ICBMs, to which the terms don't really apply. Read the history of the development of the Saturn family, and you will see the terms begin to come into play in a generalized sense, but not as definitions. My recollection is that medium lift, while not actually defined, was considered to be more or less in the vicinity of 50-80mT, somewhere around there if memory serves. It was all conversation, not definition. But nobody talked about anything less than 100mT as being heavy lift.

I will grant that the terms were loosely used, as we never thought that people would argue about them. We just understood them to be a generalized range that might mean different things to different people. The only hard number I ever heard insisted on was heavy lift being 100mT. Anything less than that was an intermediate development step, not a lift capacity. We never really cared about anything else because we  were going to the moon and that needed heavy lift. Every other rocket that was conceived was designed around what the mission might need. It wasn't "light" or "medium" or "heavy". It was "appropriate". Whatever the mission might need, that's what the rocket was designed to. But nothing less than 100mT was considered "heavy lift".

If folks today want to redefine these terms to better suit todays diminished capacity, be my guest. Just don't get insulted if a greybeard laughs at you. It's not meant to insult; it's just funny.  :)
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline marsavian

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Re: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars
« Reply #362 on: 04/13/2008 07:21 PM »
Just curious but what did you do in the Apollo program ? Love to hear some stories as it was definitely the most interesting thing that's happened in Space.

Offline kraisee

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Re: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars
« Reply #363 on: 04/13/2008 09:55 PM »
This is the scale I've been taught...

Ross
"The meek shall inherit the Earth -- the rest of us will go to the stars"
-Robert A. Heinlein

Offline clongton

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Re: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars
« Reply #364 on: 04/14/2008 01:09 AM »
Quote
marsavian - 13/4/2008  3:21 PM

Just curious but what did you do in the Apollo program ? Love to hear some stories as it was definitely the most interesting thing that's happened in Space.
After I got out of the service I got to work on the F-1. Started off as a lowly draftsman.
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline marsavian

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Re: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars
« Reply #365 on: 04/14/2008 05:29 AM »
Thanks. The F1 was a great engine and the Saturn V a marvellous rocket, an immense tragedy that it was cancelled. Where did you end up on the program ?

Offline mikers

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Re: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars
« Reply #366 on: 04/16/2008 09:54 AM »
Quote
clongton - 13/4/2008  1:48 PM

Quote
mikers - 13/4/2008  5:44 AM

Equating 'heavy lift' to "100 metric tons to LEO" is entirely arbitrary and absurd.;
Back in the day when these terms were first defined and used:
Redstone didn't apply - it was a temporary "lift" - period.
Atlas and Titan launch vehicles were considered light lift
Saturn-1B was considered light lift with the ability to put 15.3mT into LEO
Saturn-V was considered heavy lift with the ability to put 110.6mT into LEO
We designed several, but didn't build, any medium lift launchers - we didn't have time.
Von Braun himself referred to heavy lift as being at the 100mT mark. I never heard the term "medium lift" used hardly at all, and "light lift" used rarely and only in a transitory sense.

It was only after Shuttle began flying that the terms began to be used all the time and people began to literally redefine the terms to, in my opinion, make things sound like they were better than they actually were. Suddenly, Shuttle became heavy lift. Von Braun would roll over in his grave if he could hear that.

Before Apollo, all we really had were converted IRBMs & ICBMs, to which the terms don't really apply. Read the history of the development of the Saturn family, and you will see the terms begin to come into play in a generalized sense, but not as definitions. My recollection is that medium lift, while not actually defined, was considered to be more or less in the vicinity of 50-80mT, somewhere around there if memory serves. It was all conversation, not definition. But nobody talked about anything less than 100mT as being heavy lift.

I will grant that the terms were loosely used, as we never thought that people would argue about them. We just understood them to be a generalized range that might mean different things to different people. The only hard number I ever heard insisted on was heavy lift being 100mT. Anything less than that was an intermediate development step, not a lift capacity. We never really cared about anything else because we  were going to the moon and that needed heavy lift. Every other rocket that was conceived was designed around what the mission might need. It wasn't "light" or "medium" or "heavy". It was "appropriate". Whatever the mission might need, that's what the rocket was designed to. But nothing less than 100mT was considered "heavy lift".

If folks today want to redefine these terms to better suit todays diminished capacity, be my guest. Just don't get insulted if a greybeard laughs at you. It's not meant to insult; it's just funny.  :)

Thank you for this trip back to the days... I'm an old semiconductor/wafer/software kind of guy from the Silly Valley, Do Feel free to laugh at me, though, I'm a graybeard just like you ( I suppose), I can take it...  and not care about it.  For the record, feel free to even insult me, if it's funny -- I like a good joke.  

Perhaps I'm thinking about this rocket stuff too literally pragmatic, but just saying "Heavy Lift" is "100 metric tons to LEO" seem absurd and not substantiated.

For example, currently,  I would say 25mt to LEO is Heavy Lift, provided we can assemble bigger pieces out of these.

Best Regards.

Offline kraisee

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Re: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars
« Reply #367 on: 04/16/2008 12:39 PM »
25mT is just the heaviest lift which we currently have.   In that context its impressive.   But its still not "Heavy Lift".   We had that once.   We need it again.

Ross.

"The meek shall inherit the Earth -- the rest of us will go to the stars"
-Robert A. Heinlein

Offline clongton

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Re: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars
« Reply #368 on: 04/16/2008 12:58 PM »
Quote
kraisee - 16/4/2008  8:39 AM

25mT is just the heaviest lift which we currently have.   In that context its impressive.   But its still not "Heavy Lift".   We had that once.   We need it again.

Ross.
My edit: We had that once. We don't have it anymore. We need it again.
Chuck - DIRECT co-founder
I started my career on the Saturn-V F-1A engine

Offline meiza

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Re: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars
« Reply #369 on: 04/16/2008 01:48 PM »
We don't.
There's a reason the multiple heavy lifts of history are not around anymore - they were not sustainable.

Offline tnphysics

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Re: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars
« Reply #370 on: 04/17/2008 12:24 AM »
Heavy lift is pointless IF Mr. Speck succeeds AND we don't need inordinant amounts of shielding mass (meaning that EM fields provide adequate shielding or that we can reduce transit time to <3 months).

Else heavy lift, orbital/surface assembly, or depots are a must.

Offline Lampyridae

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Re: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars
« Reply #371 on: 04/17/2008 04:23 AM »
Getting a human to Mars is one thing. I believe we have the technology right now to send one or two humans to Phobos and have them come back wasted, virtually insane and with a high probability of cancer but alive. For that, 25mT lift will do fine. Think of it as the Beagle 2 of manned spaceflight. But of course, Beagle 2 didn't make it. As do a lot of lightweight amateur satellites.

For decent manned science missions, you need 100mT launchers. For fusion-powered ships to Jupiter, you will still need 100mT launchers. 25mT is simply not an efficient enough division of mass for long-term manned spaceflight.
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Online Eerie

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Re: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars
« Reply #372 on: 04/17/2008 08:37 AM »
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Lampyridae - 16/4/2008  11:23 PM

Getting a human to Mars is one thing. I believe we have the technology right now to send one or two humans to Phobos and have them come back wasted, virtually insane

Not if you connect them to internet.  :laugh:

Offline rsp1202

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Re: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars
« Reply #373 on: 04/17/2008 01:04 PM »
Then their insanity is virtually guaranteed, on top of losing the ability to spell correctly.

Offline meiza

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Re: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars
« Reply #374 on: 04/17/2008 01:50 PM »
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Lampyridae - 17/4/2008  5:23 AM

For decent manned science missions, you need 100mT launchers. For fusion-powered ships to Jupiter, you will still need 100mT launchers. 25mT is simply not an efficient enough division of mass for long-term manned spaceflight.
(my bolding)

What is this based on?

And further, what is long term and what do you expect the flight rate of the 100 t launcher to be?

I think reusable launch vehicles and ISRU are the long term solution.

Offline kraisee

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Re: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars
« Reply #375 on: 04/17/2008 03:26 PM »
Can't comment on Lampy's assumptions, but for ours "long term" we would define as the point where our Lunar program switches into high gear - around 2020, three years after our initial landing mission.

In 2020 our flight rate would be between 8-12 Jupiter-232's and 2-3 Jupiter-120's per year (facilities limit is 21 Core's per year).

Total LV yearly budget would be $4.3-5.0bn per year respectively.

Total lifted useful payload mass would be approximately 900-1,350mT per year, again respectively.

Short and Long Term DIRECT Milestone Targets:
Close the Gap by 2012.
Human Lunar return by 2017.
ISS life-expectancy upgrade by 2020, again in 2030.
Lunar outpost construction by 2025.
Continual routine ISS & Lunar access continues while we prepare for...
Mars mission #1 by 2031.
NEO missions dictated by technology readiness, *perhaps* even before Mars mission #1.

Ross.
"The meek shall inherit the Earth -- the rest of us will go to the stars"
-Robert A. Heinlein

Offline meiza

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Re: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars
« Reply #376 on: 04/17/2008 07:34 PM »
1000 tons per year - that's just the 50 flights per year for a 20 ton carrying RLV. More for smaller vehicles - meaning either a higher rate or more units.

Offline FunFlying

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Re: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars
« Reply #377 on: 04/18/2008 02:13 AM »
So many people think the grass is greener on the other side, If only this or that.  The reality is that pegging our aspirations on a $30B Ares I & V development program is fraught with risk.  NASA's history of rocket development is miserable, just look at the thread on "shuttle vs. reality": http://forum.nasaspaceflight.com/forums/thread-view.asp?tid=12711&posts=66&start=1  The dreams and aspirations in the early 1970’s were fantastic, 40+ flights/year, space station hubs, OMVs, OTVs, all would lead us down a golden path to solar system expansion.  Sadly, reality never quite lived up to the dreams and people are now blaming the shuttle for keeping us stuck in LEO.

Once the shuttle reality became clear we moved on to the dreams of NLS, NASP, X-33 and numerous other equally well motivated programs.  So after spending many, many billions of dollars chasing new silver bullets we are still struggling to finish the second piece of the grand space exploration architecture scheme from 35 years ago, the space station.

3 years ago during and following ESAS, many pointed out the numerous issues contained in this “bible” of space architecture studies.  But many on this site pontificated the wisdom of Stanley and the NASA architects of the SDLV concept that eventually became Ares I & V.  Following ESAS numerous problems arose (most of which were predicted by the ESAS skeptics), forcing change after change.  We are now facing an Ares I that will shake people to insanity and an architecture that is no where close to being able to support the lunar mission and are as many years away from first flight as we were 3 years ago.

Now, many of the same original defendants of ESAS are once again looking to a new silver bullet.  But this time it is different, if only we spend $12.5B and a miraculously short 4 years developing the new Jupiter 232 we will have this incredibly, operationally efficient 100 mT rocket and all of our problems will be solved.  Just believe us, we will save so much money on launch that all of a sudden we not only can concurrently support ISS and lunar missions, but we will be able to afford 4 annual lunar missions instead of two.  It is amazing how rosy a rocket looks on paper.

Supporting a robust presence on the moon, or colony’s on Mars, fusion star ships may eventually benefit from heavy lift (50 T, 100 T, 500 T?).  On the other hand, we have delayed crewed mission beyond LEO for 40 years hoping, praying for the rocket that will make space access a negligible portion of exploration.  Current plans will have us wait another 12 years on rocket development before once again we timidly venture beyond LEO.  

I for one am very tired of the continued glassy eyed dreams of some distant future.  While NASA continued to swing for home runs the DoD and commercial companies slowly improved what was already in hand.  While the existing rockets aren’t yet capable of the $500/lb ideals that sold shuttle to congress and the public we have rockets that are approaching 100 consecutive successes, with capable operations that can clearly support America’s next crewed forays beyond LEO.  Are these the vehicles that we want for ever more?  Heavens no, but it is a start.  

I for one want to see us take the next steps of human exploration with the kids currently in college at the helm, not waiting for their kids to grow up as I have, constantly dreaming rooted to Earth of that rocket on the horizon that never quite flies.  

Offline Lampyridae

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Re: 100mT Heavy Lift vs. 25mT Medium Lift for Lunar & Mars
« Reply #378 on: 04/21/2008 02:26 AM »
Quote
meiza - 17/4/2008  11:50 PM

Quote
Lampyridae - 17/4/2008  5:23 AM

For decent manned science missions, you need 100mT launchers. For fusion-powered ships to Jupiter, you will still need 100mT launchers. 25mT is simply not an efficient enough division of mass for long-term manned spaceflight.
(my bolding)

What is this based on?

And further, what is long term and what do you expect the flight rate of the 100 t launcher to be?

I think reusable launch vehicles and ISRU are the long term solution.

It has been demonstrated by both the DIRECT guys and by Antonio that there is always a large overhead operations cost, whether you are sending 1kg to LEO or 100mT. For the foreseeable future, this is not going to go away. Therefore, the cheapest way to lower costs to orbit are to increase the size of the rockets but not to a ridiculous level, requiring all-new pads, crawlers etc. is just a waste of money. 10 flights per year is kind of the sweet spot for ROI and it's about as much as existing infrastructure can handle.

Barring a massive shift in political winds, I don't see NASA as pioneering low costs to orbit. The only way they can make that happen is to be given a task that requires large upmass of low-value cargo. STS failed to reduce LEO access cost partly because there weren't enough missions annually. ISS ironically increased the shuttle $/kg to orbit because of its costs.

As a government agency, cutting costs means firing people. Firing people means you have fewer people lobbying for you, which means your budget gets cut. This is a vicious cycle and the only way to get them to reduce costs is perversely to get them to do *more.* Hand them an aggressive schedule, and hope that the administration doesn't have an agenda. The agenda cannot be escaped; DIRECT is not a magic rocket but one which accepts the reality of the system. If I were designing DIRECT I would scrap the SRBs for LRBs eventually as part of the roadmap. But as we can clearly see, ATK is along for the ride no matter what alternatives people care to crank out.

As for the long term solution, I doubt reusable vehicles will be able to match the $/kg performance to LEO of large, expendable or partly expendable rockets. Reusable vehicles will most likely be exclusively for passengers; the main cargoes they will carry will be small stuff like station supplies and mini-satellites. Over the next 20-30 years I expect the trend to shift gradually towards reusable first stages. However, nobody is going to put costly and time-consuming reusable solutions on the critical path for the moon and Mars. 25mT EELV is more likely than that.
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