Tuesday, August 16, 2011

On Coffee Cups and Restricted Planning

Today is a momentous day, for I have purchased a new coffee mug. For almost a year, I have been sporting the standard JPL coffee mug. It’s blue and generic. Also, a piece of junk. Also, I hate it. It waves the banner of inadequacy, thinking that its deficiencies are something to be proud of. Speaking of its deficiencies, let's focus on its structural integrity – or lack thereof:

A drop in the sink and crackkkkkk. Son of a biscuit.

Since the Mug Drop Incident of 2011, I have been going with an old standby:

It’s a remnant from the LASP days. Sufficiently stained from lack of washing, it’s like cast iron skillet of coffee mugs: flavor baked right in. Eat your heart out, Paula Dean.

Of course, the standard open-ended coffee cup provides no longitudinal spill protection. If the local gravity field suddenly flips upside, what in the crap am I supposed to do? What I needed was a new portable mug. The JPL store didn’t have any good ones until recently. This morning, though, I poked my head into the store… and behold!

Its major features: 
1) Unimpeded Coffee Delivery Orifice (CDO)
2) High-rate Air Exchanger (AE)
3) Aerodynamic design for hypersonic reentry
4) Thermal protection for long-duration coding binges
5) Easy-pop lid (EPL) for tactical refill operations
6) Thumb indent for maximum grippage
7) The aura and presence of a true coffee mug, making me look seasoned and important

Right. Now. On to a real topic.


Determining when a given planning day is “restricted” – roughly meaning we don’t know the full the state of the rover and more than a full sol is still left to execute before the sol(s) in question today execute – is a non-trivial process. It’s a function of many things, including but not limited to: 

-Allocated time with the DSN
-Direct to Earth (DTE) and Direct From Earth (DFE) communication window times
-Earth-Mars Geometry
-Earth planning day constraints
-Per-sol downlink latency
-Presence of dragons
-Coffee left in the cup before refill required

Some of those things we can't control. Some of them we can. We've got a guy that puts all of this information in a giant spreadsheet and works some magic. With a wave of the hands and a refill of the coffee (I’m making the leap of faith that he does drink coffee, which is, of course, a reasonable assumption, as you can’t be human and not drink coffee), the spreadsheet tells us which days (sols) are nominal, which are restricted, and which are ‘tweeners – slide and tight.

We spend up to three weeks in restricted planning mode; we usually get about two weeks of nominal, and a maybe week of tight/slide bookending this. The cycle is never the same, but it’s always predictable. 

There are several curious aspects of restricted planning. First and foremost, there is a change of gears throughout the project. There are, at most, 3 tactical planning days between Monday and Friday during a restricted week. This means less tactical shifts to go around. Even if you are, say, scheduled for up to half of your working week to MER, you probably won’t meet that in restricted weeks.

For multi-mission goonies like me, this opens some other doors. My mindset goes to another tier; not a lower tier, not a higher tier… just a different tier. I always say that, “I can go get real work done now.” I bury this statement in a few layers (at least seven,) of irony to make sure nobody takes it too seriously. 

By way of example, for a few weeks I’ve been involved in what we’re calling an “Agile Science Team” study to investigate fast-reaction-time mission planning time for spacecraft like Dawn and Rosetta. It’s cool, because it’s all orbital mechanics and attitude dynamics, it’s all fields-of-view and line-of-sight, it’s all dynamic events and comet plumes, and it’s all high-level abstractions. 

The lack of scheduled tactical time with MER means I get to focus on side tasks like this one. For this task in particular, this free time bit me in the ass – precisely because, as it turns out, it’s very difficult to say anything truly meaningful about a spacecraft trajectory. It's just a path in space, and it means nothing on its own. The abundant free time allows me to dwell on this task almost too much. Four hours of staring at plots later, I’ve got nothing to say except a few hundred words in a Word document.

Trying to get this same kind of thing done while buried in MER tactical work is more of an adrenaline rush. Remember, when on MER tactical duty, all other work takes second priority. However, you can find those nooks and crannies in the day to answer those half-dozen questions and email threads sitting in your inbox. Your answers become quick, to the point, lacking in capitalization, devoid of recognizable grammatical structure. The chances of this adrenaline-fueled answer being useful is about 50-50, a veritable shoot-first-ask-questions-later shotgun approach to the job. Sometimes you look like a total badass. Sometimes you just look stupid.

By way of another example, let's pretend there's a mini-crisis going down on another mission you work with while you're on MER tactical duty, planning nominal sols — day in, day out, day in, day out. A crisis like, I don't know… the ops guy spills coffee on his keyboard and radiates an accidental "backflip" command to his spacecraft. (Note to self: this command does not exist.) Something like that. An email races to my inbox, reading something like, "Anomaly… blah… coffee… blah… SOS." The adrenaline kicks in, just like in the other case, but you have to practice subduing it. You can't pack up and leave — MER comes first. You can't gut-react with shotgun emails — you'll only add rumor and crisis to what is likely already a rumor-filled crisis. 


In restricted planning, when my MER shifts are more rare, I can zip on up to help the crisis. It's about balancing priorities. Your ability to look like an idiot notwithstanding, you're able to focus your focusy focused focus on another group of people.

Of course, we have the usual slew of MER team meetings that get scheduled every week regardless of the planning schedule. During nominal planning weeks, attendance at these meetings is low. A good number of folks are in the sequencing room on tactical duty; the rest are supporting downlink analyses and the like to keep the tactical wheel well greased. Restricted planning weeks come along, and as if somebody said, “Free beer at the IST meeting,” the room fills up.

This week, there was a special presentation by one of our summer interns, Will. He danced around some subjects, presenting some well-made charts with worthwhile commentary to back it up. A few months back, we had Paolo tell us about some traversability analyses he did for the MSL project a few months ago, which was used to help them select a landing site. (I thought Gale Crater looked best, too, based on Paolo’s work, although the decision hadn't been made by NASA; besides, work like his is only one piece of the pie.)

Every once in a while, the IST team chief will catch us off guard: "Ok, if there are no more round-table discussions… it's time to review flight rules." [collective sigh] To make up for it, Project Manager John Callas likes to do a lunch-time movie. Recently, it's been one of the episodes of "From the Earth to the Moon." Sweet.

Then… then… we can feel those nominal sols coming back up. Everyone knows when it's coming: Fridays, usually 3-sol planning days, become 2-sol planning days. Then, it's game time: limber up your IST muscles, because it's non-stop insanity for the next couple weeks. Then we can breathe again.

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