I am the Investigation Scientist for HiRISE, our highest resolution camera; that means that I am the representative at JPL for the HiRISE team. Our targeting specialists and Principal Investigator operate HiRISE out of the University of Arizona in Tucson. You can read more about them and see all of the fantastic images that HiRISE has taken here: http://hirise.lpl.arizona.edu/. Part of my job is to make sure that the spacecraft management at JPL has heard the HiRISE team's point of view as they make decisions (and to pass along the spacecraft management team's point of view back to the HiRISE team). I work to keep the lines of communication open between all these groups and to help keep camera operations running smoothly.
Our standard imaging process takes about three weeks to go from identifying which targets are observable in a planning cycle, to acquiring the actual images, and doesn't usually require any special assistance from me. However, sometimes we get a request for an unusual observation by HiRISE. One such call came in long before the Mars Science Laboratory touched down on Mars. The Curiosity rover team asked us to take an image as the rover was coming in to land. That landing didn't happen until August 2012, but we first started looking at what was required to take this image back in January 2011.
If you've ever taken a picture out the window of a moving car, you know that some portions of the picture are crisp and in-focus but due to the motion of the car, others are blurred. For this once-in-a-lifetime image, the HiRISE team needed to make sure that the descending rover was crisp even if the background surface was blurry. Plus they needed to ensure that the exposure time was not too long (overexposing the bright parachute), or too short (making the image too dim and noisy to see anything) - and there was no way to retake the image if our calculations were wrong. The important pieces of information to successfully take this image included: what time is the image being taken, how far apart are MRO and MSL at that time, what are their relative speeds and positions, and where exactly the camera needs to be pointed. The team needed all of this information to be able to turn the MRO spacecraft at precisely the right speed to take a crisp image, at exactly the right time to catch MSL on the parachute. Some of this information came from the MRO navigation team, some from the MRO flight engineering team, some from the MSL navigation team, and some from the HiRISE team itself. My job was to keep an eye on the discussions to make sure that everyone was getting answers to their questions - and if they weren't, to figure out who was the correct person to ask.
Over the months, the MRO flight engineering team designed the turn, making sure that it did not move the solar panels too far away from the Sun (to maintain acceptable power levels) and that it would get the orbiter in position for both the image and for MRO's antenna to listen to MSL as it descended through the Martian atmosphere. The team updated this design as new predictions came in as to where exactly both MSL and MRO would be, and as the MSL team decided that they'd really rather that HiRISE took the image slightly later to try and get the rover after the heat shield had separated. The HiRISE team asked for a few tweaks to get the camera oriented exactly right. The final set of commands was uplinked to the spacecraft three days before landing - and then we waited nervously to see if all our calculations and predictions were accurate.
You can see the results for yourself in this image: