Looking at the world, we can see that even if not perfect, there are many cases of things which are done "outside of the market" but does works, from CERN to Appolo project, EDF/SNCF as I said in my original comment, European-style universal healthcare, ... it feels to me that being libertarian in this context is more like akin to refusing vaccines and keeping Azathoth alone.
When you mentioned economic "engineering," the first thing that occurred to me were various schools of macroeconomics and their proposed measures for economic planning via monetary, fiscal, trade, and other policies. Speaking as someone who has spent considerable effort trying to make sense of this supposed "science," I really don't see anything there but pseudoscience driven by ideology, hubris, political expediency, and rent-seeking.
What you mention here, however, is in the domain of those much older kinds of interventions that I spoke of: public infrastructure spending, wealth redistribution, and patronage of arts and sciences. Unlike the modern macroeconomic "science," you could have an interesting discussion about those even with an ancient Roman statesman. I am definitely not opposed to them in principle, and I think they should be judged on a case-by-case basis.
However, I believe you are far too optimistic in evaluating the outcomes of the contemporary such policies. For example, if properly done, government patronage of science can work wonders, but if not, it can give rise to a diabolical system of perverse incentives that will thoroughly corrupt the entire field of science in question -- and in a way that will still make it look fully legitimate to the general public, and make the critics who understand the terrible truth seem like laughable crackpots. Similar things can be argued about other government enterprises too, with corruption and disastrous bungling often rampant under a veneer of perfect respectability and (often sincerely deluded) pretense of success. And while we clearly won't agree about the extent this is happening, given the confident off-hand style of your examples, I definitely think you're badly underestimating this extent.
Or is the convention against discussing politics here silly?
I propose a test. I'm going to try to lay down some rules on voting on comments for the test here (not that I can force anybody to abide by them):
1.) Top-level comments should introduce arguments (or ridicule me and/or this test); responses should be responses to those arguments.
2.) Upvote and downvote based on whether or not you find an argument convincing in the context in which it was raised. This means if it's a good argument against the argument it is responding to, not whether or not there's a good/obvious counterargument to it; if you have a good counterargument, raise it. If it's a convincing argument, and the counterargument is also convincing, upvote both. If both arguments are unconvincing, downvote both.
3.) Try not to downvote particular comments excessively, if they're legitimate lines of argument. A faulty line of argument provides opportunity for rebuttal, and so for our test has value even then; that is, I want some faulty lines of argument here. If you disagree, please downvote me, instead of the faulty comments, because this post is what you want less of, not those comments. This necessarily implies, for balance, that we not excessively upvote comments. I'd suggest fairly arbitrary limits of 3/-3?
Edit: 4.) A single argument per comment would be ideal; as MixedNuts points out here, it's otherwise hard to distinguish between one good and one bad argument, which makes the upvoting/downvoting difficult to evaluate. (My apologies about missing this, folks.)
I'm going to try really hard not to get personally involved, except to lay down a leading comment posing an argument against abortion, a position I don't hold, for the record. The core of the argument isn't disingenuous, and I hold that this argument is true, it just doesn't lead to my opposing abortion. I do not hold the moral axiom by which I extend the basic argument to argue against abortion, however; I'm playing the devil's advocate to try to help me from getting sucked into the argument while providing an initial point of discussion.
Which leads me to the next point: If you see a hole in an argument, even if it's an argument for a perspective you agree with, poke through it. The goal is to see whether we can have a constructive political argument here.
The fact that this is a test, and known to be a test, means this isn't a blind study. Uh, try to act as if you're not being tested?
After it's gone on a little while, if this post hasn't been hopelessly downvoted and ridiculed (and thus the premise and test discarded as undesirable to begin with), we can put up a poll to see whether people found the political debates helpful, not helpful, and so on.