Friday, March 30, 2018

2000 Sols on Mars: What Goes Into Documenting Another World?

The second in our two-part series on Curiosity's 2000th Sol on Mars. In this article Brittney takes a look at the public reaction to the day and reflects on choosing that perfect image to commemorate the occasion, in this case from an observation she herself designed, planned and ran on Mars! What goes into producing that top line image? Read on to find out. You can read the first article, written by Charissa Campbell and talking about operations, by clicking on this link.

By Brittney Cooper

Mars Science Laboratory (MSL), better known as Curiosity Rover, celebrated its historic 2000th sol on Mars last week. 2000 Martian days equates to roughly 3 Martian years, which has allowed the rover a great deal of time to traverse Gale Crater. Along the way, the science team has used MSL to analyze Mars’ geology, all the while monitoring the atmosphere and its processes as the seasons change each year.
To celebrate this historic occasion, the BBC published an article featuring a collection of images captured by the rover throughout its journey. It turned out that a triptych of images taken as part of an observation I proposed were selected to be included in the article. It was really cool to see them alongside others in such a large outlet. An unexpected (but positive) result of those images being published came in the form of discussions with friends and family about what my actual role was in the capture of those images.

This made me realize that the inner workings of mission planning, and the “how’s” and “why’s” pertaining to data collection are not very well known beyond past and present mission participants. This is one reason that analog missions are run on both small and large scales, but the number of participants in those exercises is still relatively small. This leaves a great deal of the population questioning why interplanetary missions often “only” capture monochromatic images, or don’t have a live HD feed streaming back to Earth 24/7. I think a lot of these questions stem from the common misconception that mission operations consist of a few individuals sitting in a room full of monitors with a joystick. While I knew that was not the actual case before I became a part of MSL, I would have been pretty clueless to the realities of mission operations if it wasn’t for my participation in a two week analogue mission, years prior. Even with that experience, I had a lot to learn once I became a part of a real mission, and there is still so much that I don’t know (and thankfully, don’t have to know).
While I really do wish that we could have a constant HD stream from Curiosity’s mast, constraints on power, data, and time, are critical when working with a rover on an entirely different planet. It’s important to remember that at any point in a planetary mission, a good number of things could go wrong. This means that pushing the limits of those afore-mentioned constraints could result in an irreversible effect that could limit the abilities of the rover in the future, or even completely take it out of commission.
Curiosity has been “running” (so to speak) since it landed on Mars. What I mean by “running” is that for almost 2000 sols, the rover has been driving, snapping images, and consistently taking active and passive scientific measurements of both the surface and atmosphere. In between all this activity is when the rover finds time to “nap” and charge its battery. In order for the rover to have enough power to execute all the desired observations, there needs to be a certain amount of time allotted for charging the batteries. This means that time for activities is also tightly constrained, and every second that the rover is “awake” is carefully planned and accounted for.  Every activity is not only a drain on power, but also results in the accumulation of data in one form or another. The rover and its instruments collectively possess a finite amount of memory, meaning that data volumes associated with observations must also be considered.
It is simply not feasible to have a highly energy-intensive, memory-intensive video feed going at all hours of a Martian day, and there is simply not enough satellite coverage over Mars to be able to continually relay data back to Earth. Curiosity is on Mars to answer scientific questions, and while taking pretty pictures to engage the public is also super important, it is not the main objective of the mission.
 MSL team members are quite limited in what they are able execute on the rover as a result of all these strict constraints, and thus every activity and observation must be justified with a science, engineering, or outreach rationale. In order to run a new activity on the rover (such as the one that produced the images I had featured in the BBC article) it has to go through a few stages of approval.
Typically you will present a proposal for your activity to a science theme group (which is full of fellow scientists and collaborators working on topics pertaining to the broader theme of the group). This proposal can be relatively informal, but it needs to outline the scientific justification for the activity, including relevant background to the scientific objective. It should also include proposed methods for obtaining the data, alongside rough estimates on power consumption, data volume and timed duration. Lots of discussion can follow this presentation, as this is the audience that will be most familiar with your scientific goals and most in-tune with how it will be practically implemented.
A lot of knots can be worked out with that first presentation and can allow for the development of a more streamlined proposal to be presented to the entire science team in a “science discussion”. During the science discussion, any major concerns regarding your proposal will be brought up, and must be addressed before the observation can be approved to run. By the end of this process your approved activity may look a little different than what you began with, but making compromises is all part of the process.
I went through the afore-mentioned process as a relatively new member of the team (with a lot of guidance from my research advisor and team members), and the images featured in the BBC article are just a small fragment of what came out of that.  It was a terrifying idea to me at first, but this process taught me a lot about working as a team, and introduced me to new people working on the operations and engineering side of things. It was also a crash-course in collaboration and really boosted my appreciation for just how incredible it is that some 500 (give or take a few) people can work together on a mission and accomplish as many unified goals as they do.
I’m currently working on the analysis of data from my proposed observation, so I am hesitant to give away too many details at this point, but stay tuned and it will hopefully be available for the world to see later on this year!

Acknowledgement: Thanks to our Post-Doc Christina for helping to make the cloud photos internet-ready, and for penning their caption!

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