The HiRISE instrument on the Mars Reconnaissance Orbiter (MRO) is a powerful camera that is capable of imaging the Martian surface at a scale of up to 25 cm/px (10 inches/px) from its orbital height of 300 km. This allows us to see and interpret objects as small as a living room coffee table from space! Although in heavy use as a research tool, the camera's operators at the University of Arizona allow outside scientists and members of the general public to submit imaging requests through the HiWish program.. A small number of these requests are incorporated into HiRISE's regular imaging schedule and made available to the requester. This means that you too can act as an instrument targeting scientist for a day!
NASA's operations budget is very tight and for missions to continue receiving funding, they need to demonstrate that they are still returning exciting new scientific data. This means that HiRISE is heavily booked in its primary role as a scientific instrument. Only a handful of HiWish requests are selected during each planning cycle, and nearly all of these images are selected on their scientific merit. When submitting a HiWish request, you will need to fill out a 1000 character mini-essay describing why the target has scientific merit. Picking a target just because it is scenic will likely mean that your image sits in a queue forever.
Imaging rationales that are submitted to the HiWish program are not made public, and unfortunately this deprives us of models for writing a successful justification. To provide a model for using the HiWish program, I have organized a list of successful HiWish requests I have written. Most of these requests were submitted to help my research, but others were submitted for fun. I am not sure how my percentage of succesful requests compares to other people submitting requests, and I have also been fortunate enough to be in contact with two members of the image scheduling team. So your mileage may vary when using my requests as a template.
However, even successful requests may sit around in the queue for a while. A year or two between submission and selection is not uncommon. There might be a few reasons for this. An important one is available data volume. The amount of bandwidth available for HiRISE observations varies based on several factors. These could be Mars' distance from Earth (further distance = more time to transmit data = less data recieved during a Deep Space Network downlink session), the time of season where you want to observe (terrains may be heavily shadowed at the time of day MRO flies over), and the need to use the MRO as a data relay for surface missions.
MRO commonly pulls double duty as a communications relay for landed missions. When in communications with those missions, the satellite is usually oriented in a way that prevents it from pointing HiRISE at the surface. Rotating into and out of this orientation takes a few minutes, meaning there are several longitude swaths that are relatively poorly imaged in comparison to the rest of the Martian surface. These swaths are referred to as data holes. Currently, two data holes are present on the Martian surface, which may slow your request's progress through the queue.
Page updated: June 9, 2022