To the Moon! (Part II)

The thing with instrument choice is that it can change rapidly. You have a preliminary instrument list so you can come up with an idea about the amount of data you’re going to be dealing with (which can start the design of the C&DH and telecomm systems), but when you make a decision on the mission architecture, everything can change. But you have to start somewhere, and instruments are as good a place as any.

Mission architecture is one of the most exciting and challenging areas of systems engineering. How are you going to launch from Earth? This requires the choice of a launch vehicle, entirely dependent on the volume and mass of the payload your mission will be carrying. So…you can’t even begin to decide on this until after the rest of the mission design is nearly complete. Once you escape Earth’s gravitational pull, how do you get to where you want to go? This seems to involve complex math and a lot of turns to make use of gravity assists. Just to get to the moon there are different stages – where we will be releasing the rocket boosters from the launch vehicle, where we will be firing engines to push the payload into the correct path, where we will be entering the moon’s gravitational pull, where we will enter a parking orbit around the moon, where we will send the lander down to the surface.

Beyond that, the seemingly simple choice of an orbiter, lander, rover, return capsule can turn into a heated debate. You have to have an orbiter to communicate with Earth. But should you have a rover/lander or just a lander? The cost goes up, but your samples might not be as good. And when you launch the return capsule from the moon, should it dock with the orbiter and the orbiter come back to Earth (very Apollo-like), or should the return capsule launch from the moon and shoot straight back home? Again, trades with cost, risk, and complexity (probably just a combined term for dual increased risk and cost!).

We’re using a brand new technology for our rovers in this concept. All of the senior systems engineers we’ve talked to think we’re crazy for using it, but I’m of the opinion that if people aren’t willing to take risks and say that new technology should be utilized, it won’t ever be used – and this is true for everything from space systems to new software. Plus using this solves so many potential issues that may come up because of the unknown terrain and surface conditions. And if we function under the idea that the technological development for this particular robot is being funded by the manned space program….well, we have several fewer issues with the cost AND we can say that it’s proof of technology and demonstration of capability for future manned missions.

Once you have your mission architecture, you can rethink your instrumentation if needed. Otherwise, you start work on specific subsystems. Some become more challenging than others, but in general you have to consider the following:

Communications
Command and Data Handling (C&DH)
Attitude Control Systems (ACS)
Thermal
Power
Radiation
Structures
Propulsion

Slowly, every part comes together, each fitting snuggly against the last. It’s like putting together a dynamic jigsaw puzzle. The nice thing about this type of puzzle, though, is that you can shave off a little of the edge if it doesn’t fit perfectly!

I am really excited to see what our final product looks like. And it seems as though other people are too – I was asked yesterday evening if the team would be ready for “prime time.” Apparently this guy has a new senior level advisor or something that is going to be on Lab next week. And one of the associate directors of the Lab thought it would be a great idea to have us present to this third-highest level in the NASA hierarchy.

It’s an amazing opportunity. But let’s just say that my stress levels are about as high as they possibly could be right now. As M said yesterday, I should be living in my cube with a case of redbull, my computer, and a pillow.