16 April 2012
The Mars Science Laboratory Rover Curiosity is a huge and phenomenally complex machine, and operating it is no easy task. And when so much taxpayer money and so many careers are on the line, you want to be ready to roll when you touch down on Mars. That’s why this week I am at the Jet Propulsion Laboratory (JPL) in Pasadena for “Operational Readiness Test 8” (ORT8).
ORTs are dress rehearsals for the actual mission. Everyone is given a part to play and we spend a week or so simulating rover operations as completely as possible. It is during ORTs that the team really learns to work together, rapidly interpreting data from the rover and planning the next sol‘s activities (a sol is a martian day). As you might guess from the number, there have been multiple ORTs before this, mostly focused on specific aspects of the landing and the first few days of operations while everything is still being tested. ORT8 is different because it is going to be a simulation of normal surface operations. The goal will be to scout out some nearby rocks, select one for more detailed analysis, and then start positioning the robotic arm to make measurements.
Since our actual rover is currently hurtling through space on its way to Mars, we will be using a duplicate that lives in the testbed at JPL. But for our purposes, it might as well be on Mars. We will be simulating a specific set of sols well into the mission, and all communications with the testbed rover will be timed to match periods during those sols when the Mars orbiters will be available to relay information between the rover and Earth. Even the delay for the radio signals to travel between Earth and Mars is included in the test.
And yes, we will be working on “Mars time”. Our schedules will be set by the rotational period of Mars, which has a day that is about 40 minutes longer than an Earth day. This means that each day we will start working a little bit later. For a week-long training session, this isn’t too bad, but during primary operations, when the team will be working on Mars time for 90 sols, it will lead to keeping some very strange hours. The orbital passes make things even more complicated, so instead of a nice 40 minute increment each day, the times jump around a bit depending upon when we can communicate with Mars.
To prepare for the ORT, we have “flight schools” for a couple of weeks beforehand. These are teleconferences where the folks at JPL educate all of us scientists and newbies about everything from where to find food at JPL to the intricacies of planning complicated rover measurements. There is a whole bevy of software and websites that we need to learn how to use to make operations run smoothly, and these telecons introduce us so that we aren’t completely in the dark when we arrive at JPL.
Each instrument team also has to develop its own software to analyze their data, and work out step-by-step procedures for each of the roles. Since landing is still a few months away, these ORTs provide a chance to test the software and procedures and learn what works (and what doesn’t) so that things can be improved for the real thing.
I have some experience as a Pancam Payload Downlink Lead (PDL) on Spirit and Opportunity, but for this mission, I have been assigned multiple roles with more responsibility. I will be serving three roles during this week’s ORT. I will be the “mini-Keeper-of-the-Plan” (miniKOP) for the mineralogy science theme group (MIN STG), and the ChemCam Payload Uplink Lead (PUL) and Payload Downlink Lead (PDL). (In case you weren’t already aware, NASA runs on acronyms. Part of the filght schools includes a webpage that serves as a cheat-sheet for the hundreds of acronyms that we use.)
The miniKOP is a newly invented role, based on experience from previous ORTs. The idea is that each science theme group has discussions and comes up with a rough idea of the sorts of observations that they would like the rover to make. The miniKOP uses planning software to keep track of the group’s plans so that they can then be shared with the rest of the team. In the past, this was the job of the science theme group lead (STL) but it is hard enough to lead the discussion, let alone deal with entering everything into the software. Thus, the miniKOP position was created.
PULs are the ones who listen to what the team wants and then translates that into sequences of commands to be sent to the rover. It’s a big job that takes all day, and there will actually be two PULs per sol for each instrument. One for the first shift and one who takes over for the second shift. For ChemCam, the job is broken down further, and there is an engineering PUL and a science PUL.
PDLs are the other side of the coin. The PDL is the person who looks at the data as it is downlinked from the rover, makes sure that everything went according to plan, and makes the preliminary science interpretations to share with the team.
To train for each role, you typically first are a “shadow” for that role. So, for example, on Tuesday I am shadowing the ChemCam science PUL2, following them around all day and learning how to do everything.
It promises to be a stressful and exhausting week, but there is no better way to learn something than to do it. There are a handful of other ORTs spread throughout the summer, so that by the time MSL touches down in Gale crater and gives us our first glimpse of Mt. Sharp beckoning in the distance, we will be ready to rove.