"We went to the Moon as technicians; we returned as humanitarians." --Edgar Mitchell

"We came all this way to explore the moon, and the most important thing is that we discovered the earth." --William Anders

Tuesday, February 5, 2013


This week, I went into the Mitchell Library on campus and walked around the Current Publications section. The article I chose was from the AIAA's Journal of Spacecraft and Rockets, which means that it's a bit more technical than the last article I chose. It was definitely more brutal. First paragraph, and I learn a new word: rovibronic. I'm still not entirely certain what that means.

The article that I chose was "Absolute Radiation Measurement in Venus and Mars Entry Condition" by Brett A. Cruden, Dinesh Praghu, and Ramon Martinez. It can be found in the November-December 2012 issue of the Journal of Spacecraft and Rockets (Volume 49, Number 6). Picking this article might have been a mistake. From what I understand, because the composition of different planetary atmospheres is different, this results in different levels of radiative heating. Previously, it was mostly convective heating that was mostly predicted, but the size and speed of the entering body (....) can make this less accurate.

Now, I've taken optics and chemistry, and I understand that different chemicals and elements emit different spectral lines. I understand that as you heat things up, they emit blackbody radiation. Basically, we're all glowing due to our heat. This paper explored how the velocity and pressure caused the different elements and chemicals in the atmosphere to glow. Essentially, as the body moves at different speeds through the atmosphere, it "triggers" different elements to emit radiation that can be detected through these spectral lines. This is in addition to the blackbody radiation that occurs from the heating up of the gasses. I think.

Part of what this paper was trying to establish, however, was whether the software that they had been working on (at NASA Ames) would be an effective model/tool for predicting the radiance that would happen from planetary entry. The authors decided that not only did this software need work, but that the experimental methods needed to be refined. This part was the take-home lesson for me. Even though these guys are spending their entire work week doing research and working with million-dollar pieces of equipment, at the end of the day they still produce an article that explains how they can be better. It might be good to keep that in mind.

Wednesday, January 30, 2013

Let's Go To The Moon!

"The fundamental limitation to expansion into the solar system is not technological, but economic." - James R. Wertz

To bring everyone up to speed: I read an article called "Architecture for Developing an Economically Viable International, Large-Scale Lunar Colony" by James R. Wertz about a week and a half ago, and I've been picking at my response to it ever since. It's mostly that I've not had a whole lot of time to devote to writing something that is solely for my own pleasure.

When reading this article, I had quite a few moments where my engineer mind gave a snort and said "that's a stretch!" However, my biggest sticking point was not ultimately at the core of his argument. More or less, Wertz was saying that the most dramatic reduction in cost would be obtained not by reducing launch costs to a small fraction of what they were at the time this article was written (1999), but by fully utilizing COTS (commercial off-the-shelf) technologies and not sending up more hardware than was needed. This struck me as a similar to the strategy that Robert Zubrin outlines in his book The Case For Mars (which I haven't entirely read yet, so no spoilers, plox): utilize as many resources as possible in situ. This means using the regolith on the Moon as building materials for everything from habitats to chairs and desks, as well as finding non-terrestrial sources of nitrogen and other gases. When coupled with using as much COTS tech as possible, establishing a 1000-person colony goes from costing trillions of dollars to mere tens of billions. Wertz makes the bold claim that it would cost less than the ISS. Let that sink in for a minute before I dive into some of the nitty-gritty.

Has his claim sunk it well enough, now? Alright, moving on.

I want to talk about his treatment of the problem of launch vehicle costs, first, as it's probably the most visible aspect of almost any space mission. Wertz never says exactly what the average cost of launching a kilogram into LEO (Low-Earth Orbit) is in 1999, but I'm going to go out on a limb and say that it's pretty much the same as it is today (ignore SpaceX for a moment, I'm getting there). Well, this guy builds in as a major assumption that launch costs are going to drop by a FACTOR OF 50 in the indeterminate future. This factor of 50 includes what is essentially a bulk-rate discount, bringing the target cost of getting mass to the moon down to $1600/kg. That sounds like a lot, especially when you consider that the average person weighs about 75 kilograms (no, I don't have a source for that; I'm pretty much making it up). It's definitely out of my budget! Let's take out the factor of 5 that was taken into account for launching a lot of mass to the moon. This causes the cost to bump up to $8000/kg. However, let's look at SpaceX, now. If you go by their website (which doesn't have cost per kg, but rather has cost and weight separately - I did the math), then the absolute lowest price to get a kilogram of whatever to Geostationary Transfer Orbit (GTO) is .... *drumroll*

*opens envelope*


And that's about half of what any other launch vehicle can do right now. (I almost wrote lunch vehicle, and now I'm hungry) It's not even to a lunar transfer orbit! And Wertz included a list of companies and the corresponding vehicles that were trying to hit the factor of 10 reduction that was needed in the first place, all of which are no longer being actively developed. This list includes the X-33, which makes me sad because that vehicle had a Cool Factor of over 9000.

But, as Wertz explains, this launch cost in conjunction with the "traditional" cost model for lunar colonization (if anything concerning what we've never done before can be considered tradtitional) is only going to get the development cost down to a figure that is in excess of $5 TRILLION. That's a T, ladies and gentlemen. That's still a humongous number. This is actually largely because projects like lunar colonization are usually approached as design solutions looking for a problem. Everything is specifically engineered for that environment, without specifying exactly what the requirements are for a lunar colony. If something doesn't need to be extensively engineered, it shouldn't be, was basically his point. The trick is figuring out what needs to be engineered, and what can and can't survive the harsh lunar environment. A smartphone, for instance, might not be able to survive the radiation as well as, say, a power drill.

So more or less, this article emphasizes Systems Engineering processes to bring the cost of engineering projects like this down. Just as SE has to be modified for Small Sats, it would also need to be modified for something like high-capacity colonies. And it all comes down to defining the requirements adequately without predetermining a design solution.

There were some other interesting tidbits in here, a lot of them about where the colony would get its air (he proposes bringing some of it from one of the gas giants - isn't that getting a bit ahead of itself) and other resources and minerals that aren't readily available on the lunar surface.

What I got from this, though? Wertz is totally Alt Space.

Anyone reading? If you got this far, AND you read the article (or part of it), let me know what you think of his proposals in the comments!

Thursday, January 17, 2013

I Am Alt Space

As part of my self-betterment for 2013, I am going to be reading at least an article a week and writing a response to it. This is similar, but more structured, in approach to my original goal of "learn something new every day." That one didn't work out very well at all... Not that I didn't learn something new every day (I'm in engineering for chrissake!), but I had a hard time writing about it, which I think was mostly due to time constraints.

I've already picked out my first article! It's called "Architecture for Developing an Economically Viable International, Large-Scale Lunar Colony" by James R. Wertz. It's from some conference proceedings which are pretty impossible to find in a library (I tried for hours), but it's available on the internets! I will be reading this after I finish up this post, which should be pretty quickly.

I found this article in the book Space Mission Engineering: The New SMAD. The first few chapters are just overviews of space engineering: the economics, history, and community. I was very sad when I read the chapter where it broke astro engineers into different communities and stated that human spaceflight was outside the scope of the book. Let me tell you, though: this is a huge book. And I have every intention of more or less reading all of it. Because I'm crazy like that.

The Human Spaceflight Community wasn't the only community that I was excited to read about, though. I saw this section titled "Alt Space" and I was confused. If you know what Alt Space is, don't laugh or spoil it for everyone else...  Everything else was self-explanatory, but I had no idea what this was. So I flipped to the end of the chapter, which is totally acceptable in this type of book, and read that section. Apparently New Space is a subset of Alt Space (or is Alt Space if you ask Wikipedia), but it more or less boils down to the people who think we should fully utilize space: its resources, space, and... space... Alt Space adherents view other members of the space community as having too narrow a focus and no passion, while everyone else views these crazies as... well... unrealistic and crazy. Neil deGrasse Tyson and Buzz Aldrin are, as best I can tell, part of this community. So was Wernher von Braun. Guess which one I am?

Pretty much a textbook case.