I wrote a sequence that Ashley's robotic arm activities would fire off each time we wanted to take an image. I needed to use almost no data volume to avoid treading on our science priorities for the day. So I commanded the rover to shrink the images down from their native 1024 x 1024 to just 256 x 256 pixels; one-sixteenth as much data. We could get all 17 images for the 'price' of about 1 normal MI image. I knew they would be badly out of focus, so shrinking them shouldn't really cost any 'detail' in the pictures. We regularly shrink images from the hazard cameras and navigation cameras, but a search of both Spirit and Opportunity's past activities showed that we had never asked either MI to shrink its images 'in flight'. There was no reason to suspect it wouldn't work, but it was just one more thing to worry about. The compression we use for the MI isn't deterministic – we don't know exactly how much data each image will use; we simply give it a quality level and it compresses them as much as necessary. I estimated something like 2 or 3 megabits of data in total.

After the rest of the planning day was completed, Ashley's robotic arm activities had been handed over to John Wright, another veteran of MER, for review and delivery (rover planners always work in pairs on Opportunity). The approval to radiate commands to the rover for Sols 5000 and 5001 was given, and we all went home. More than a few of us spent the night tossing and turning. What if the arm had a problem while doing it? Would it forever be stuck waving hopelessly in midair? What if we miscalculated the pointing and the images wouldn't line up? What if it generated so much data we would bump all the science data out of the downlink queue and the science team wouldn't get their data?

The images were due to make it back the following morning. It was one of JPLs regular days off – an 'RDO'. But we all came in to work anyway. I had barely slept, partially because my wife and I had welcomed our daughter into the world just 6 weeks before on Christmas day. But if I'm honest, mainly because I was just so nervous about our selfie.

Crowding round the workstation of former Cassini ACE, now MER systems engineer Michael Staab, we watched for the packets of data to come down in real time. The data started flowing. The ID for thumbnails, tiny preview images, started flowing. Then the actual MI images. Before we had time to grab our laptops and start looking for pictures, another rover planner and image pipeline engineer, Hallie Gengl, shouted across the cube-farm walls, "What are you all doing? I've got pictures here." They must have been small to downlink so fast from Mars Odyssey.

I had MAESTRO, a mission planning tool, already open on my laptop. I hit refresh and all 17 images were there. The thumbnail of the very first image told me everything I needed to know. It worked. There was the rover's camera mast – its face – looking back at us.