Mars Oracle Update

I've been laying off on the Mars Oracle design document for a few weeks now. Because of finals and these two chapters for that writing contest (see previous post), I simply couldn't work on it as often as I would like to. On top of this, I missed the turn-in deadline. The reason is that this window of opportunity MarsDrive gave us was meant to produce updates to existing documents, not for these (like me) who realized they had to scrap their existing plans and start all over again. I racked up quite a page count over these three months, but it wasn't enough to justify a final turn-in.

The good news is that the Mars Oracle document is, despite its unfinished state, over four times as dense as my original sample return plan and roughly two-thirds longer. Unlike the older plan, it contains raw numbers and estimates. For example, I finally figured out the ascent vehicle's possible fuel requirements, Delphi's likely atmospheric entry parameters, and the estimated trajectories for both the outbound and return legs. All of that required mere algebra, and a few choice freeware. That truly surprised me, since I assumed these areas would be beyond my limited education in aerospace engineering.

One change I made in the overall design since my last posting:

Diborane-carbon dioxide combustion has been dropped for the ascent. Upon further research and analysis, I found that diborane would weigh down the entry vehicle too much to be viable (since it is imported from Earth). To make matters worse, diborane is a dirty fuel that leaves too much solid byproducts (which can choke off the nozzle throat after a certain time).

Instead, the ascent vehicle will be fueled with liquid carbon monoxide and oxygen procured from atmospheric CO2 via high-temperature electrolysis. Carbon monoxide isn't the best rocket fuel, but it burns clean with oxygen and is environmentally friendly (for Mars, not for Earth!). Overall, this combination's specific impulse is good enough that the propellant tanks won't need to be too large. But the best part is that Delphi will be landed empty. Because it will be extremely light for a sample return lander, combined with new methods for precision landing coming online, thousands of sites at many different elevations will be available. Since 100% of the return propellants are generated from the Martian atmosphere, there is no need to store any liquid en route. This will do wonders for the mission cost.

I should be able to return to Mars Oracle after this month, possibly earlier. Stay tuned.