Preparing for the 2009 International Year of Astronomy ASP Conference Series, Vol. 400, c 2008 M. G. Gibbs, J. Barnes, J. G. Manning, and B. Partridge, eds. Passengers on Voyages of Exploration: The Beautiful and Surprising Work Amateurs Can do with Raw Image Data from Planetary Missions Emily Stewart Lakdawalla The Planetary Society, 65 North Catalina Avenue, Pasadena, California 91106, USA Abstract. Many recent planetary science missions, including the Mars Ex- ploration Rovers, Cassini-Huygens, and New Horizons, have instituted a policy of the rapid release of “raw” images to the Internet within days or even hours of their acquisition. The availability of these data, along with the increasing power of home computers and availability of high-bandwidth Internet connec- tions, have stimulated the development of a worldwide community of armchair planetary scientists, who are able to participate in the everyday drama of ex- ploratory missions’ encounters with new worlds and new landscapes. Far from passive onlookers, many of these enthusiasts have taught themselves image pro- cessing techniques and have even written software to perform automated pro- cessing and mosaicking of these raw data sets. They rapidly produce stunning visualizations and then post them to their own blogs or online forums, where they also engage in discussing scientific observations and inferences about the data sets, broadening missions’ public outreach efforts beyond their direct reach. These amateur space scientists feel a deep sense of involvement in and connection to space missions, which makes them enthusiastic (and occasionally demanding) supporters of space exploration. 1. Introduction It is a great time to be an armchair planetary explorer. As the Internet has developed, missions have expanded their outreach by providing rapid releases of raw image data for the public to download. And as people upgrade their homes to high-speed Internet service, more and more of them are developing the capability to consume the high volumes of image data being produced by active missions. At the same time, consumers are transitioning to the use of digital rather than film cameras, which means a large segment of the public is familiar with methods of digital image processing. And finally, the proliferation of sites that promote the sharing of user-generated content, places like online forums, per- sonal weblogs, Flickr, Picasso, and YouTube, means that people can share their work with other enthusiasts. They can comment on each other’s products, share information about data resources, learn image processing tricks from each other, and become inspired to teach themselves to do more. The end result is that there is now a thriving international community of amateur imagesmiths who actively follow every day of a space mission. This community doesn’t just consume data 436 Passengers on Voyages of Exploration 437 from space missions; they can make positive contributions to space science as well. 2. Where Amateurs Get the Data Amateurs take advantage of two main types of data sources. First, some NASA missions have adopted policies of automatically spewing all the image data that they acquire onto special “raw” image websites. Currently, the three mis- sions that provide data in this way are the Mars Exploration Rovers,1 Cassini- Huygens,2 and Phoenix;3 recently, New Horizons4 did also. Typically, these data are sent to the Internet before flatfielding, dark current subtraction, and other basic calibration steps have been performed. The data also usually have an automatic contrast stretch applied that assigns the brightest and darkest few percent of the pixels in each image to extreme white and black values. Because of the lack of calibration and automatic contrast stretching, these images are not particularly useful for science. Instead, they provide snapshots of where a spacecraft has most recently been—a view out the porthole of a spaceship. These images allow the public to follow missions in “real time,” seeing the im- ages as quickly as the science teams do. Depending on the relative timing of downlink and the sleep cycles of science team members, the public may actually see the data first! What can amateurs do with such raw data? One popular activity is to make animations. For instance, one could follow the deployment of Phoenix’ robotic arm on the third day of its mission by taking the six images that were returned from Phoenix’ camera and assembling them into an animation. The rovers take many images with engineering cameras as they drive, which can be assembled into movies that show their motion across Mars. Cassini regularly captures time-series of motions in the rings and atmosphere of Saturn or ap- parent rotation or motion of moons during flybys, which make for enthralling animations. No unusual software is needed to do this. Many children are taught how to make slide presentations using Microsoft PowerPoint or similar software in the classroom; a simple animation can be made by dropping spacecraft im- ages onto separate slides in a presentation, and then rapidly advancing the slides. Alternatively, many pieces of home photo album software allow the creation of slideshows, which is a fine way to show an animation that has a small number of frames. Amateurs can also make mosaics, showing landscapes on Mars and Titan, or use right- and left-eye images to create anaglyphs, viewable with red-blue 3D glasses. They can even make three-filter color images, although producing 1Raw Images for Spirit and Opportunity: http://marsrovers.jpl.nasa.gov/gallery/all/ 2Cassini-Huygens Raw Images: http://saturn.jpl.nasa.gov/multimedia/images/raw/ index.cfm 3Phoenix Lander Raw Images: http://phoenix.lpl.arizona.edu/imageCategories lander. php 4New Horizons Science Operations Center Raw Images: http://pluto.jhuapl.edu/soc/ 438 Lakdawalla approximate true-color views is made difficult by the automatic contrast stretch that has been applied. 3. A Few Experts Open Access to Many Dabblers Amateurs are also learning how to make use of calibrated data that has been archived to NASA’s Planetary Data System5 or their equivalents at ESA (the Planetary Science Archive6) and JAXA (Data Archives and Transmission Sys- tem7 and Hayabusa Project Science Data Archive8). These data are typically stored in formats that are difficult for the average user to search, open, and process. However, a few self-taught image experts have written software that enables the average user to access PDS-formatted data. For example, an Icelandic space artist named Bj¨orn J´onsson has developed a piece of command-line software titled IMG2PNG,9 which can batch-convert files stored in the Planetary Data System’s IMG format to losslessly compressed, 8- bit or 16-bit Portable Network Graphics (PNG) format, making them accessible to all. He has recently updated his software to open and convert New Horizons LORRI image data, stored in 32-bit FITS format. Another expert, Gordan Ugarkovic, from Croatia, has developed a similar piece of software, QUB2PNG,10 for converting Cassini’s VIMS image cubes into multiple PNG files. Probably the most impressive piece of amateur-produced software is the Midnight Mars Browser11 developed by an American programmer Michael Howard. Midnight Mars Browser automatically downloads all raw images from the Mars Exploration Rovers, produces RGB color composites and anaglyphs, and auto- mates the production of mosaics, which are displayed as virtual reality panora- mas that can be dynamically moved around the viewer (figure 1). Howard’s software also provides basic download capability for Phoenix images. Through the efforts of a few such experts, the vast catalogues of planetary data that have been returned from all space missions are being opened up to the regular Internet user. Thus amateurs are now increasingly capable of consuming image data from planetary missions. Amateurs can (and often do) produce more and prettier versions of images from active planetary missions than the science teams have time to do, and they can produce them very quickly; science teams should seriously consider offloading some tasks of creating presentation-quality images to the amateur community. 5Planetary Data System: http://pds.jpl.nasa.gov/ 6Planetary Science Archive: http://www.rssd.esa.int/index.php?project=PSA 7Data Archives and Transmission System: http://www.darts.isas.jaxa.jp/index.html.en 8Hayabusa Project Science Data Archive: http://hayabusa.sci.isas.jaxa.jp 9IMG2PNG: http://www.mmedia.is/bjj/utils/img2png/ 10QUB2PNG: http://www.unmannedspaceflight.com/index.php?showtopic=4759 11Midnight Mars Browser: http://midnightmarsbrowser.blogspot.com Passengers on Voyages of Exploration 439 Figure 1. Screen capture from Michael Howard’s Midnight Mars Browser (MMB) software showing a panoramic view from the Mars Exploration Rover Opportunity’s Navigational Camera (Navcam) on sols 1,327–1,329 (October 18–20, 2007), when the rover was sitting on the sloped surface of Duck Bay, looking in to Victoria Crater. MMB automatically downloads the component Navcam images (seven of which are tiled to create the view shown here) from the Jet Propulsion Laboratory or San Francisco Exploratorium websites, and displays images from selected time intervals in a virtual-reality panoramic view. By clicking and dragging with the mouse in the panorama window, a user can spin the rover’s 360-degree view around in azimuth and elevation; keystrokes advance the view forward and backward in time. Navcam images courtesy NASA/JPL-Caltech. 4. How Professionals