From time to time I get really excited about in-situ resource utilization on the Moon and Mars. Lately, it's been one of those times. I've been filling out my NASA application and it's making me think about why I really want to be an astronaut. And in a nutshell it comes down to Mars.

Current Mars ISRU information on the web seems a little hard to come by. It can be separated into two major categories: atmosphere processing and regolith processing. You could substitute polar ice cap processing for regolith, but it'll probably be a few missions before we are in a position to do both.

The best reference I can find on atmospheric ISRU for Mars is Zubrin's paper on the Reverse Water Gas Shift reaction. Here's a summary of the science:

The Martian atmosphere is about 95% CO₂. The energy requirements to separate out anything else are too great for smaller missions. There is a process for dissociating the carbon dioxide directly into carbon monoxide and oxygen. The carbon monoxide can be frozen into propellant grains and then burned with the oxygen in a cryogenic hybrid rocket motor. However, this motor technology is not mature and the dissociation process, known as zirconia electrolysis, requires fragile components and is not considered robust enough for flight.

Unfortunately, the alternatives to zirconia electrolysis require hydrogen. There is hydrogen available in the ice caps, but let's assume it's out of reach for now. Since we have to send a vehicle to Mars to perform the ISRU anyway, it might as well contain some hydrogen [at the cost of some launch mass].

The goal, then, is to maximize the hydrogen usage on Mars. The technique of choice is called the Sabatier electrolysis reaction. The reaction is as follows:

It is highly exothermic and has an enormous (10⁹) equilibrium constant driving the reaction to the right. It will occur spontaneously in the presence of a proper catalyst (nickel - cheap, or ruthenium - more efficient) at temperatures above 250 C. The efficiencies of test reactors have been between 90% and 96%. A condensor can easily separate the water and methane products.

Now we have methane, a reasonable fuel, and water which can be electrolyzed in accord with:

The oxygen is kept as an oxydizer (or for CELSS in manned scenarios) and the hydrogen is recycled back into the Sabatier reactor. However, there is only half as much hydrogen being recycled as was put in (assuming 100% retention) because methane contains hydrogen. For every 1 kg of hydrogen brought to Mars, this method can produce 4kg of methane and 8kg of oxygen.

The reactor is vastly superior to the zirconia device because it is mechanically simple and very robust. The water hydrolysis technology is very mature, rugged, and quite efficient (90%).

Now the disadvantage: the ratio of methane to oxygen is far from optimal. The process described above creates 2kg of oxygen for every kg of methane. However, the optimal burn mixture ratio for O₂ and CH₄ is 3.5:1. Add to this that we may want to use some of the oxygen for CELSS and it is clear that we need an oxygen producing reaction in addition to the Sabatier process. The only alternative is to throw away some excess methane but that's rich in hydrogen which we are trying to conserve at all costs.

We could use the zirconia method to make oxygen, but we've already ruled it out as too flimsy. Instead, we employ a reaction called the Reverse Water Gas Shift (RWGS) given by

The carbon monoxide is given off as exhaust while the water is condensed and fed into the same water electrolysis device that the Sabatier reaction is feeding. In essence, this process boosts the amount of water created by the Sabatier, which in turn gives a boost in oxygen output per unit methane. All of the hydrogen used in the RWGS process can be recycled (theoretically) so it doesn't eat significantly into the hydrogen stock for the Sabatier reaction.

The only problem is that the RWGS technology is not very mature and it is a difficult reaction to drive to completion. Getting this process efficient is the one key technology remaining in this scheme. Assuming it can be done, then combining the three reactions given above leads to

The overall reaction is exothermic, requiring no net input to operate! This assumes proper heat management to get the heat from the strongly exothermic Sabatier reaction to the other two endothermic reators. Furthermore, the net output is 4kg of methane and 16kg of oxygen for every 1kg of hydrogen imported. This is a net propellant leverage of 20:1 and a mix ratio of 4:1. This leaves some bonus oxygen left over for CELSS!

The Zubrin paper goes on to talk about some alternatives to the SE/RWGS reactor that produce ethylene or methanol instead, but I'm rambling so I'll save that for later.

Nina and I went to White Sands over the weekend. This was the first time that I've been there during the winter. The daytime temps were still in the 60s and 70s, but at night it got cold enough that ice formed all over my tent and I was generally uncomfortable. I have a hard time sleeping in cold air for some reason. This could present a problem for Denali... or perhaps I just need to get a warmer bag.

Nina liked White Sands a lot and has already expressed an interest in going back this summer. The Space History Museum in Alamogordo is always a blast for me, and it was good to see that they had installed some new displays. Most interesting to me was the fin can of a real V2 sitting out in the rocket park outside. Nina got a picture of me standing in front of a poster whose headline is "The Shame of Rocketry" [see my rocketry page to view it].

We made a breif road-side stop at the Valley of Fires malpais but didn't stay longer than it took to shoot a couple of pictures.

Last stop on the trip was the VLA, which Nina had never seen and was very excited about [being an astrologist and what-not...]. The array re-tasked while we were standing out by the dish on the walking tour. It was fun to watch.

All-in-all it was a great trip. The best part was that we did it all in 2 days, which means we could do similar stuff on a regular weekend whenever. This was a three-day weekend and we had originally planned to go snowboarding on Saturday, but that got cancelled due to exhorbitant rental fees and the realization that we were both broke and in debt.

The weather during the trip was awesome with warm temps and sunny skies. The only exception to this was the portion of the trip we spent in Los Alamos, where it was raining and crapulent constantly.

MIT finally sent me my reimbursement for my fall stipend. I can now pay off my bursar's bill and get get squared away there. This represents half of my current debt. Wh000t!

It's almost like spring here. My friends in the midwest and on the eastern seaboard are experiencing record colds, the temperature in Boston yesterday got to -15 deg F. Here it was raining lightly all day and low clouds were lurking between the mountains. This morning there is a great bright fog all throughout town. The temperaure is cool but not at all unreasonable.

My parents (almost certainly my mom) sent Nina and I a valentine's day gift which arrived yesterday. It was some walnut carmels (I hate walnuts) and the french card game "Mille Bournes" which my family used to play when I was very young. This is very odd, considering that I have never received a valentine's day gift from them before (aside from chocolates when I was a kid). The carmels basically went straight to Nina and some friends we had over last night, but mille bournes is still a lot of fun and holds a certain amount of nastalgic value for me.

I got Nina some roses, but otherwise Valentine's is one of those holidays I don't really get into. She had some flowers delivered to my office today - more stargazer lilys, a redux of last year. There were some complications because the lab is at security condition 2 which means flower delivery guys can't even get onto lab property and I had to hike out to the road to find him to get them. Add to this that his message on my voice mail about a delivery for the Otowi building (not my building) got deleted as voicemail spam, oops!

The stargazers haven't opened yet, but once they do I expect to have a very... fragrant office.

Peter and Steve and I went down into Pueblo Canyon yesterday after work and made a first stab at making the orienteering map. It went well and I think both of them will be up for helping make the map(s) from now on. It has become apparent that it will take a long long time to do.

I suppose I should say a few things about the Columbia tragedy given my plans to apply to the astronaut corps when I get my degree. It wasn't clear from the NASA TV stream what was happening at the time. The first real indication that they were aware that something was terribly wrong was when the FDO asked the TNC to lock the control room doors and advised no one to make or receive any phone calls. At that point I had a pretty good idea of what was soon to be revieled by amateur videos shot over texas.

Regardless of whatever the findings of the accident investigation board are, it seems clear that Columbia suffered either a thermal or structural breakdown in the left wing and as a result lost attitude and succumed to the enormous aerodynamic and thermal loading at Mach 18. Other than a few minor sensor dropout warnings, it seems unlikely to me that the crew had any warning of their impending doom. Once the GCS could no longer correct for the forces on the shuttle, catastrophic failure would have followed so quickly that those aboard probably didn't notice.

To be sure, it was a human tragedy. While the loss of life was not particularly overwhelming in magnitude, it was very much in the public eye. These were representatives of their respective countries in a noble endeavour for a great cause. As highly trained, highly educated scientists working towards the advancement of the collective knowledge of the human race in a way that few were capable of, they were exceedingly valuable, though perhaps indirectly, to us all.

When I was in fourth grade, teaching my fellow students how to code in LOGO, we took a break to watch the Challenger launch on mission STS-51L. When it exploded 72 seconds after liftoff, I was still too young and innocent to understand the implications of the disaster. As far as I was concerned, the explosion "looked cool."

Nevertheless, that moment went into my memory as one of three times that I witnessed a very tragic and public loss of human life. The next time this happened was a year and a half ago when I turned on my TV while I ate breakfast before going to my plasma physics class, just in time to witness the second plane fly into the world trade center live.

The destruction of Columbia was the first of these events to really hit me close to home. I'm not so susprised that something like this might happen; I understand the myriad risks that face astronauts. What really struck me was a sudden realization that I was prepared to give my life for something, and that this wasn't necessarily an impossible outcome for me.

I spent a lot of time contemplating what it meant to be an astronaut and what they represent. And the conclusions I came to included that I really believe in what they're striving for - even to the point that I would sacrifice myself to further those goals.

And that's a difficult thing to admit to yourself. And a startling realization for me.

The cave dig went really well. I made a fancy register out of a blank journal I found at R Books and put it in a tupperware container. I put a copy of the 1969 Monitor article in it so that other visitors to the cave can get some historical perspective.

We opened up some serious blow holes in the floor of the lower chamber that were very encouraging. I hope this project becomes a regular occurance. Attendance has been good, with 9 people for the first dig and 8 this time.

This guy Philo, who I guess is sort of a rogue independant caver in the area, heard about the dig on the grotto mailing list and showed up with his son and some friends. I guess he was expecting something a little more extreme. They showed up in full vertical gear and with a 5' long pick axe. Of course, you can see the entire cave in about 2 minutes without any vertical gear and there is nowhere to swing that huge pick at all. It was humorous, anyway.

Yesterday I wanted to get out and stretch my sore muscles from the dig, so Nina and I went for a walk in Pueblo Canyon here in town. I scoped it out as a possible venue for an orienteering race and decided to start making a map there.

The terrain is great for orienteering, with lots of small cliffs, good open running forest, foot bridges over impassible canyon, etc. Plenty of space for a long advanced course too. I downloaded the new version of OCAD and was pleased to find that they have increased the max object count for the demo version from 500 to 1000, making a real orienteering map much more feasible.

I got some satellite imagery of the canyon and the topo map online and started the base map. Hand-tracing contours really sucks. Especially when there are a ton of them and they are really close together (i.e. when there are canyons present). But I got a good base map done and now I get to start the fun part - the field work.

Chimley Steve and Peter have expressed interest in helping make the maps, so I'm going to try to do an hour or two after work here and there with them until we finish the map. If we can get a few maps made by this summer, I can do an actual orienteering series like the one I participated in last summer in Boston. I suspect that the interest level here should be plenty high. I can't believe that no one is doing this already!

found myself reading an old page from this journal (June, 2001) and wishing i hadn't gotten too busy to keep updating it. The last year of my life has gone unrecorded and that's a shame; it's been extraordinary.

I'm not going to attempt to do a recap here; there is too much. But I'm going to make another shot at getting this running on a regular basis.

Since I moved to New Mexico I've become very active in caving. I've been caving at least once a month since I got here, and I've recently been elected as an officer in the Pajarito Grotto. Lots of caving pictures here.

Recently I started a cave dig project for the grotto at the Pajarito Canyon lava tube that Mike and I dug out in 2001 (see journal link, above). This is the first caving project for which I am the lead.

Our first dig day was last Saturday. Nine people showed up and we removed over 50 buckets of rubble over the course of five hours. The wind was incredibly strong and cold. Comments were made likening the airflow on this cave to that of Lechuguillia. Someone else has been digging in the cave since Mike and I were here in 2001; there was some wooden shoring evident and the upper passage had been elongated by a couple meters.

John, being the high-tech caver that he is, brought in a wind meter and measured the airflow at the entrance at 12mph. The entrance area is approximately 16 sq. ft, which gives an air flux of 300 cubic feet per second. That's 1,000,000 cubic feet per hour. This is indicative of a huge volume. He also brought his camera-on-a-stick and stuffed it into some cracks near the lower dig face to see what lays ahead. The video revealaed a 1-cubic-meter sized void just ahead, so that's something to look forward to.

We have another dig planned for tomorrow afternoon to continue the job.

In the past week, John and I have done some further research. A friend of John's indicated that he remembered reading about the lava tube in an issue of the Los Alamos Monitor [local newspaper] back in the summer of 1969. I went to the library and delved through some microfilm and found an article about a guy called Ernest Hodson who lived in White Rock and first located and excavatd the cave. He apparently did an airflow study on the cave and determined the internal volume to be appeoximately 255 million cubic meters (!!!). That's approximately a volume one square mile in footprint and 300' high. Wow. This is very encouraging.

The player-one top-fire joystick up switch is not functioning. Not sure if the problem is with the switch, the joystick, somewhere in the wiring, or in the keyboard emulator. Need to open up the cabinet and troubleshoot this.