Sauntering Vaguely Downward

[Image of a Cassini spacecraft model inside a black gimbal structure comprised of three concentric rings, mounted on a plexiglass stand and sitting on the corner of a desk.]

Now that I'm back at work, I present another of my Rare Objects from Space History for #tbt. This is a model of the Cassini spacecraft, mounted in the centre of what I can only think to describe as a gimbal. The high gain antenna is pointed toward the bottom of the photo. The model was distributed to instrument teams to aid them with pointing design. It can be rotated around three axes within the gimbal. Each circle of rotation is marked in degrees, so that from a set of numbers indicating its orientation (eg "RA & dec"), an instrument engineer can work out which way the spacecraft is pointing.

I have no idea when it was originally given to our team but it predates me joining the Cassini project (ca 2006).

As many of you know, I work on the Cassini mission as an operations engineer and have done for over a decade.

Tomorrow is the spacecraft’s final close flyby (T126) of Saturn’s moon Titan.

Just to put this into perspective for you, this may be the last time in decades that we get anywhere near Titan. There are no missions to Saturn or its most interesting* moons, Titan and Enceladus, currently funded or being built. That means there’s a minimum of ten years before a new mission could be launched. Given that the transit time to Saturn is, at a minimum, seven years and on average more like ten, that’s two decades until we can repeat Cassini’s observations.

Cassini’s impending demise makes me sad, of course, but what bothers me even more is the lack of continuity in our exploration of our solar system.

You can read the details of tomorrow’s Cassini’s observations on the NASA-JPL press release here. It includes an animation of the flyby over the surface, from the perspective of the spacecraft.

* “most interesting” being ever so slightly subjective, of course

[Block diagram of a "generic" space instrument.]

I'm giving a talk next week* and I needed a block diagram of a generic spacecraft instrument. I made one many moons ago but it looks verry dated now and is also about 400x300 pixels and I can't find the original graphics program file. So I thought, I'll make myself a new one.

I'll probably talk about the slide it's on for a minute and a half, maybe two. I probably shouldn't have spent two hours on this. I'm now trying to justify the time spent to myself by sharing it with the internet. Hi, internet!

If you're wondering what this is, it shows how a set of sensors that measure physical parameters in space (on the right in green, labeled MAGOBS and MAGIBS) are connected to a spacecraft (on the left in gold). The physical parameter, in the case of these two sensors, is the ambient magnetic field.

The FEEs transform the physical parameters measured by the sensors into electrical signals.

The ICU is the instrument control unit, which takes telecommands (TCs) and timing signals from the spacecraft and passes them to the sensors. It also takes the data passed back from the front-end electronics (FEEs) and turns it into nice telemetry packets (TMs) that the spacecraft can then package up and beam to Earth through its communications system.

The PCU is the power converter unit, which takes the standard voltage from the spacecraft (usually +28 Volts) and chops it up into secondary voltages that the instrument FEEs can use (e.g. +/- 1.5 Volts)

It all looks very simple, no? You wouldn't think this sort of thing would take a dozen years or so to implement and launch would you? Sadly, you would be wrong about that.

* And two the week after that. They are all different. Whyyyy did I think it would be a good idea to sign up to give a group meeting when I already knew I had another two talks to give? /o\

[Admin note: Entry text has been lifted and modified from an earlier locked entry because PHOTOS! Please let me know if Google Photos is still being crap and I'll put them on Flickr. I hesitated to do so because I didn't take these pictures.]

Last week, I gave my first outreach lecture in just over a year. I'm not doing much outreach any more as my schedule is pretty full, but I made an exception for this Year 4 teacher. I've known her for a few years now, from when she worked at a charity called IntoUniversity that runs courses for children whose parents haven't been to university. She was always fantastic at laying the groundwork for an outreach event, arranging for a big audience and ensuring that the children understood that what was happening was quite special. This is a totally underrated skill in outreach and in general, I think. I knew that the students would be studying space and the solar system in their curriculum, that they would know of my visit in advance and thus that they would be able to extract the most from it.

Anyway, this time I unintentionally pushed this poor lass to her limits. I turned up a week before I was scheduled to do so. It was entirely my fault as I'd put the correct time but the wrong date into my Outlook calendar.

She rallied beautifully. It helped that, superstar teacher that she is, she had already been preparing the students and teachers for my arrival ("We're getting a NASA engineer to visit us!"). Her composure outwardly unrattled, she managed to get all the Year 4 and Year 5 teachers to rearrange their lessons, and bring their children down for the lecture. I'll never forgot those 180 excited faces staring up at me from where they were squooshed together on her classroom floor. They hung on my every word and pelted me with questions for 15 minutes at the end. Then they applauded me. Some of them stood up. Some of them were cheering and whooping. This went on for almost two minutes. I have never felt so embarrassed and so pleased in my life. As they were leaving they came up to me individually - one girl just so she could hug my leg.

"Doctor Nanila," said one smiling eight-year-old boy, "How do I become an engineer?"
"Doctor Nanila," asked a serious-faced child, "If you could go into space and live on your dream world, what would it look like?"
"Doctor Nanila," said a brown-haired girl, "I saw the blood moon through my binoculars! Do you know, it was the closest the moon has been to the Earth this year?"

I have permission to post the photos the teacher took from the event. Without further ado, me and her Year 4s doing the Vulcan hand salute. Please note that I'm wearing an ESA Rosetta t-shirt. Sadly the design is on the back.

Live long and prosper! Peace! Five! Uh...fingers!

( +3 )

They've sent a bunch of handmade thank-you cards to my work, which I'll pick up next week. They're going to make me cry at my desk. <333333

Ready to fly!

I forgot to share this photo of Humuhumu after my trip to Washington DC. I brought this astronaut outfit back for her from the Smithsonian Air and Space Museum. It was worth every penny.