Heavy Lift Unnecessary

There are a lot of implicit assumptions that heavy lifters of this or that throw weight must be used for future exploration beyond low Earth orbit.

These “needs” have never been logically derived from anything.

Yet space policy and exploration architectures must be based on rationality above all. There is no excuse whatsoever to do things on a whim. Hundreds of billions of dollars, and the future of humanity’s spacefaring are at stake.

There is no foreseeable need to launch over 25 tonne monolithic payloads to low Earth orbit in lunar exploration, and probably even that number could be seriously diminished with some more thorough planning. Orion, EDS, LSAM, all are below that weight, if they are refueled using a depot in space.

If the huge development and operational estimated costs for a heavy lifter rocket go away, then that money is freed for real exploration work. In-space hardware development, more launches, more missions and operations.

Flight rate is _the_ most important way of reducing launch costs, the single largest impediment for advancement of spacefaring, and the propellant depot enables a higher launch rate. Multi-launch scenarios with a propellant depot also enable competition, redundancy and flexibility, all very good things, ensuring safety, robustness and progress.

I repeat as a summary how

1) Solutions for space exploration, like any large endeavour, must be rationally justified. No baseless assumptions should remain.

2) The need of heavy lift is a baseless assumption. It can be one of the alternative ways of execution, but it can not be a starting point or an axiom.

3) The current architecture is heavily based on the implicit assumption of heavy lift. Hence a rational space exploration architecture would examine things from the ground up. It could end up with some radically different conclusions.

4) Propellant depots is one alternative way of executing space exploration beyond LEO, and it does not need heavy lift.

5) Propellant depots can, if executed correctly, increase launch rates many fold, and thus enable lower costs, progress, reliability, redundancy, robustness – all the things that the space shuttle promised but failed to do because it was a sole solution that could not sustain a high enough launch rate and was too costly.

6) NASA at the same time should keep on working with fundamental research, to enable continuous progress trends in space technology.

7) Space exploration should look as different from Apollo as possible – there should continuity and continuous improvement possibilities, robustness and progress. The architecture should be affordable as well.

8) New space technology, like cheaper launchers, should be demonstrated at a smaller, humble scale first. That way many things can be tried and progress is faster, for the same price and effort. One failure also will not be as critical.

9) There seem to be impediments for information flow inside NASA, and many professionally acknowledged things like propellant depots, EML2 rendezvous or space tethers are never even mentioned in NASA high level planning. This is not rational.

This entry was posted in Architecture, Demotivation, Depot, industry, ISRU, NASA, RLV:s and tagged , , . Bookmark the permalink.

5 Responses to Heavy Lift Unnecessary

  1. Eric Collins says:

    Sorry for the nit, but the underlying assumptions that drive all of the mission modes you mention are the fundamental laws of physics and the use of chemical rocket propulsion. These assumptions, and their consequences, are neatly summarized by the rocket equation. This is what drives the need for large amounts of propellant to be launched into LEO, which in turn drives the requirement for the heavy lift capacity if one chooses to launch the fuel at the same time as everything else.

    As far as I know, there has been no implicit assumptions that heavy lift is the only way to meet the enormous mass requirements of manned missions beyond LEO. Rather I think depots were in the trade space with heavy lift and were probably unfairly weighted against due to the erroneous perception that multiple launches would increase the risk of a single launch putting the entire mission at risk. It was _this_ assumption that was likely used to justify the decision to go with HLV instead of depots.

    The fallacy of that assumption was explained fairly well by Jeff Greason at the Cocoa Beach meeting of the HSF committee. With depots and dry launch on EELV’s, the number of launches of critical-path, high-value payloads (e.g. EDS, Altair, Orion, crew) remains the same as for the wet launch HLV architectures. The multiple launches required to bring up the propellant can be done on cheaper vehicles that do not necessarily have to be as reliable as the launcher for the high-value payloads. Sufficient margin can then be built into the propellant deliveries such that the failure of one or two launchers will not risk the success of the mission.

    Anyway, aside from than that nit, I mostly agree with the conclusions you draw regarding the benefits of using commercial providers and for reallocating the HLV development funds towards the development of actual exploration hardware.

  2. gravityloss says:

    Watching the Greason stuff now. I know I should have watched all this earlier but just haven’t had the time and energy.
    http://vimeo.com/6037790

    He’s on the ball, but still far too kind.

    1) Pound on why the hell ESAS was so irrational? We *have to stop making irrational decisions*. They must be punished. Rationality won’t be gotten unless it is *demanded*.
    How can we be sure we are not making similar mistakes now? The system has to be rational from the ground up! No secrets.

    2) Why 25 t would be the smallest piece? Granted, that’s probably explained in length elsewhere.

    And multiple other things.

  3. gravityloss says:

    I’m harsh. Make no mistake, Greason is a top level guy and his presentation is the best one I’ve seen.

    I’m just so tired of NASA theater.

  4. Carl says:

    Remember what the economic incentives of government programs are, and ESAS will make much more sense.

    Private enterprise serves the consumer, because the consumer pays for it voluntarily and may easily switch to another service provider if service is relatively poor.

    Government takes money from people by threat of violence (pay your taxes or we throw you in jail or shoot you). They have *no* incentive to serve the taxpayer. They have *every* incentive to serve those who give them money — the politicians who are trying to appease their constituencies. This is why the segmented SRB design was chosen in the first place, even tho it was by far the worst design out of 4 contenders. So government programs are chosen based on how well they favor certain groups with political ‘pull’.

    Also, government programs are rewarded for failure. If your program fails, that means you didn’t have enough money and should be given more. If you succeed, that means you should be given more money so you can succeed further. There is *no* mechanism for readily inducing a shrinkage or efficiency increase, other than some vague and quickly forgotten promises to the taxpayers every 2, 4, or 6 years.

    In short, government can’t go out of business, so they have no reason to be efficient. Because of this, we should give them as little money as possible, so they will waste as little as possible.

  5. gravityloss says:

    Yes, there’s a problem of government employee incentives. Unfortunately, governments are necessary to avoid going into anarchy or a corporate controlled society. It’s a bit like armies. They are a waste of resources from a top level point of view, but nobody can shut down theirs if the others don’t. Somebody will always fill the power vacuum.

    They are also useful to operate / own natural monopolies. There are things that all citizens own a part of, like roads. You don’t want to grant a private company a monopoly – it will just raise prices and make astronomical profits since the users have no choice. (There have been experiments here of new highway projects being bought from a contractor with a ten year payment period – we’ll see how that works.)

    So, there’s a natural “ecological niche” for government like entities – and a democratically chosen periodically partially replaced one is the best system we have come up with so far to handle that in a semi working fashion.

    It’s by no means perfect and we always have to remember to limit its tendency for growth. But it’s not ultimately bad either.

    Also one has to remember that humans are not just maximum self profit seeking machines – many (though not all) actually are motivated to do their job well, if it is sensible and meaningful, even if they don’t themselves get paid more whether it fails or works. I know a lot of public servants who went to their job because of big enthusiasm for the subject, not because of money or a secure job (in fact you get paid more in the private sector). Say, some city traffic planners. Universities are examples of this too – the private sector could be a much more pleasant (no politics) and highly paying position.

    And it seems the Augustine panel as well is working on personal interest for truth, justice, benevolence and plain old curiosity of how things really are – at least the Beyond LEO Subgroup.

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