AIAA 99-0691 Real-Time Lunar Prospector Data Visualization Using Web-Based Java D. G. Deardorff and B. D. Green NASA Ames Research Center Moffett Field, CA 37th Aerospace Sciences Meeting & Exhibit January 11-14, 1999 / Reno, NV For permission to copy or republish, contact the American Institute of Aeronautics and Astronautics 1801 Alexander Bell Drive, Suite 500, Reston, Virginia 20191-4344 AIAA-99-0691 REAL-TIME LUNAR PROSPECTOR DATA VISUALIZATION USING WEB-BASED JAVA D. Glenn Deardorff* and Bryan D. Green* NASA Ames Research Center, Moffett Field, California ABSTRACT trated in narrow regions around the lunar equator, leav- ing 75c_ of the Moon's surface unmapped. Since then, The Lunar Prospector was co-developed by NASA all other U.S. lunar explorations have been flybys, Ames Research Center and Lockheed Martin, and was except lbr the Clementine mission, a Department of launched on January 6th, 1998. lts mission is to search Defense mission whose purpose was to provide detailed for water ice and various elements in the Moon's sur- surface images and conduct laser-ranging altimetry, as face, map its magnetic and gravity fields, and detect vol- well as some charged-particle experiments. This mis- canic activity. For the first time, the World Wide Web is sion, which flew for 2 months in 1994, produced find- being used to graphically display near-real-time data ings which hinted at the possibility of water ice at the from a planetary exploration mis:;ion to the global pub- south pc,le. I lic. Science data from the craft's instruments, as well as Lunar Prospector, with its complement of five scien- engineering data for the spacecra-'t subsystems, are con- tific instruments and its low-altitude orbit, was designed tinuously displayed in time-varying XY plots. The to greatly extend the quality and quantity of data on sur- craft's current location is displayed relative to the whole face composition, as well as to provide detailed mag- Moon, and as an off-craft obserw:r would see in the ref- netic and gravitational surveys. At the end of its erence frame of the craft, with the lunar terrain scrolling nominal one-year mission, its circular 100 km high orbit underneath. These features are implemented as Java will be changed to an elliptical one which will bring it to applets. Analyzed data (element and mass distribution) within 10 km of the lunar surface for highly detailed is presented as 3D lunar maps using VRML and Java- explorations of regions of interest. Its instruments script. During the development [,hase, implementations include a neutron spectrometer for mapping the concen- of the Java Virtual Machine were just beginning to trations of hydrogen, and by inference, water ice; a mature enough to adequately accommodate our target gamma-ray spectrometer for mapping the abundance of featureset; incomplete and varying implementations uranium, iron, titanium, and other elements; and an were the biggest bottleneck to ( ur ideal of ubiquitous alpha-particle spectrometer for detecting outgassing browser access. Bottlenecks not s_ithstanding, the reac- related to tectonic and volcanic events. Its magnetome- tion from the Internet communit ¢ was overwhelmingly ter and electron reflectometer are mapping its magnetic enthusiastic. field, while Doppler studies of its radio signal are pro- LUNAR PROSPECT()R MISSION viding maps of the lunar gravity field (or mass concen- trations h 2 OVERVIEW Within 2 months of its launch on January 6th, 1998, The primary focus of the Apollo missions was to definitixe evidence was found for the existence of water demonstrate the feasibility of technologies for success- ice trapped in the perennially-shadowed crater bottoms fully sending people and rock samples to and from the at the north and south poles, in an amount of several gal- Moon. Most of the scientific datz collected was concen- lons pe_ cubic yard. 3 Also at this time, the first global gravity maps were made, showing the locations of mass Copyright © 1999 by the American Institute of Aeronautics and concentrations. Since then, the spectrometers have Astronautics, Inc. No copyright is assertt d in the United States under Title 17. U.S. Code. The U.S. Governmt nt has a royalty-free license yielded enough data to create maps of all the sought- to exercise all fights under the copyrighl claimed herein for Govern- after elements. 4 These maps should be considerably ment purposes. All other fights are reserv2tlby the copyright owner. refined during the low-orbit phase of its mission. *MRJ Technology Solutions. NASA Ames Research Center. M.S. Lunar Prospector is a NASA Discovery Mission. 5 T27A-1, Moffett Field, CA 94035 This new mission philosophy places an emphasis on sci- 1 A,merican Institute of Aeronautics and Astronautics enceand"Faster,Better,Cheaper"mission design and world _ith a computer, modem, and Internet connec- development. Lunar Prospector e_emplifies these goals. tion. While the earlier Sojourner and Pathfinder Martian It is a small, spin-stabilized craft that uses flight-quali- expeditions had made good use of the Web 7 to post their fied, modern technologies and instrumentation to ensure exciting images obtained from the surface and from results and minimize risk. The design is simple: a small, orbit (as well as to numerically display the telemetered graphite-epoxy drum (l.4m x 1.2m) with surface craft engineering data), this was the first time that arm- mounted solar cells and three 2.5m masts which carry chair space explorers the world over could connect to a the instruments and isolate them !¥om the bus. There is continuous, graphical display of the science datastream no on-board computer, although there is a microchip in virtually real-time. used to receive ground commands and control the space- Java was selected as the Web technology to use craft, and store the data collected while traversing the because it has a practical means of automatically updat- lunar far side. ing browser displays at the required 32-second intervals, The entire mission was realized well within a budget while incorporating the necessary features of network of $63 million, in a time frame of two years from initial connections, file reading, data manipulation, math oper- hardware development to final testing. The results of ations, graphical data display, and graphical user inter- this mission are important not only for basic scientific face. O_her Web technologies such as CGI scripts, plug- inquiry, but also have implications tbr the question of ins, or lavascript are simply too cumbersome or too how much natural resources are available for the support lightweight to meet all of these requirements. In addi- of long-lived manned lunar bases, from which further tion, since Java is a full-fledged object-oriented inter- lunar explorations could be conducted, or which could preted language, it allows the use of pre-existing class be used as a stepping stone to exploration of Mars. libraries to construct the plots themselves. Unfortu- nately, as will be discussed later, Java implementations DATA VISUALIZATION OVERVIEW on various platforms and browser versions are not nec- essarily compatible or complete, thus diluting its ideal From the outset, the Lunar Prospector mission had the goal of "Write Once, Run Anywhere". In particular, following goals: 6 older br_wsers have incomplete or ill-performing imple- 1. Obtain high-quality sciertific data about the mentations of Java featuresets. This was of concern Moon's structure, composition, and resources, thereby since the desire was to maximize access to computer providing insight into lunar origin, evolution, and utility users throughout the world, including those with low- for exploration. end or outdated systems and browsers. As will be seen, 2. Demonstrate that the philos,)phy of "cheaper, bet- some compromise was necessary here. ter, faster" can be aggressively a?plied to yield a rapid The data visualization ("Data Viz") pageset is one part development, very inexpensive planetary science mis- of the Lunar Prospector Web site located at Ames sion. Research Center (http://lunar.arc.nasa.gov). This site 3. Create an innovative education and outreach pro- includes much information about the mission and sci- gram which uses novel partnering arrangements and ence, ar_ image archive, streaming audio and video clips new technologies to stimulate public interest in plane- about the mission and the Moon, VRML renditions of tary exploration. the spacecraft and parts of the Moon, and Shockwave In regards to goal 3, part of the charter of space explo- animations illustrating some of the instrument opera- tions. The Web server consists of a collective farm of 4 ration missions is not only to return data to the mission scientists, but also to engage the public to the greatest Sun Ul-170s, an Enterprise-3000 which delivers the extent possible. At the time of the mission, Web tech- documents to the Ul-170s via NFS, and part of an nologies had begun to mature to the point where it Enterprise-5000 which collects and processes all of the became feasible to present the :aw data in near-real- access l-._gfiles. time, virtually at the same time the mission investigators The three main components of the Data Viz portion had access to it, in a way that was compatible with the (craft location, science data display, and craft health dis- "better, taster, cheaper" philoso_)hy of the Discovery play) were originally envisaged as co-occupying one series. The World Wide Web provided a pre-existing page. It soon became evident, however, that both for global infrastructure through wl_ich the data could be performance reasons, and for visual space reasons, it disseminated as soon as it reacl--ed Earth. Interpreted made more sense to launch separate Java applets in sep- results would, of necessity, lag behind weeks to months, arate windows for each of the myriad graphs and dis- but the excitement of accessing tt_e raw datastream from plays.