Citizen Science in Planetary Exploration:
Part 2

Note from the Editors: In this two-part series, we explore the role that citizen scientists (or amateur astronomers) play in supporting planetary exploration in the U.S. and internationally. In Part 1, which was featured in the previous issue, Drs. Nick Lang and Michael Kelley explored the active programs that NASA uses to engage directly with citizen scientists, and Dr. Ted Stryk explored ongoing activities in monitoring astronomical events in the solar system. Part 2 continues the story as Stryk looks at how citizen scientists engage with ongoing and past planetary missions to facilitate data processing. — Paul Schenk and Renée Dotson

Planetary Citizen Scientists in Action
Ted Stryk, Roane State Community College

JunoCam is a camera onboard the Juno spacecraft, which has been orbiting Jupiter since July 2016. The primary goal of the Juno mission is to study the gas giant’s atmosphere, magnetosphere, and interior structure. JunoCam was not funded to be a science instrument, but rather a public outreach camera designed to capture stunning images of Jupiter’s cloud tops and share them with the public. Because the camera has no science team, it relies on volunteers (anyone from hobbyists to professional scientists operating alongside citizen scientists) to handle the images it returns.

JunoCam at Jupiter

“A mind of limits, a camera of thoughts” is the name of this contribution from citizen scientist Prateek Sarpal. Jupiter inspires artists and scientists with its beauty. In this image, south is up, and the enhanced color evokes an exotic marble and childhood joy. The original image was captured by JunoCam, the camera on NASA’s Juno mission in orbit around Jupiter. This image was taken on Juno’s 22nd close pass by Jupiter on September 12, 2019. JunoCam’s raw images are available for the public to peruse and process into image products at Credit: Image data provided by NASA/JPL-Caltech/SwRI/MSSS. Image processing by Prateek Sarpal, ©CC NC SA.

JunoCam is a digital camera with a wide-angle lens that scans its targets as the spacecraft rotates. It has a 4-megapixel sensor and can capture images in both visible and infrared light. JunoCam is operated by a team of volunteers who plan and execute the camera’s imaging sequences. Anyone can participate in the JunoCam project, either by suggesting targets for imaging or by processing the raw images into stunning visualizations of Jupiter.

One of the unique aspects of JunoCam is its ability to capture images at extremely close range to Jupiter. During each of Juno’s close flybys of the planet, JunoCam captures a sequence of images at high resolution. The images are taken in a narrow swath as the spacecraft passes over the planet’s surface. The raw images are then transmitted to Earth, where they are processed by volunteers to produce dramatic images of Jupiter’s atmosphere.

Processing JunoCam images is a complex task, requiring specialized software and a deep understanding of image processing techniques. The raw images are often distorted and blurry due to the spacecraft’s motion and the turbulent atmosphere of Jupiter. The images must be aligned and stacked to remove the blur and enhance the detail. The color balance and contrast must also be adjusted to bring out the features of interest in the images. The resulting visualizations of Jupiter are breathtaking, showing the swirling clouds and storms that make up the planet’s atmosphere.

JunoCam has been a tremendous success, capturing the public’s imagination and providing a wealth of scientific data about Jupiter. The images captured by JunoCam have been used in numerous scientific studies and have helped to improve our understanding of the gas giant. The JunoCam project has also engaged the public in the exploration of space, inspiring amateur astronomers and citizen scientists to participate in the mission and contribute to our understanding of Jupiter.

In addition to imaging Jupiter itself, JunoCam has also captured stunning images of Jupiter’s moons during the spacecraft’s close flybys. In August 2021, during Juno’s 34th close flyby of Jupiter, JunoCam captured images of two of the gas giant’s largest moons: Ganymede and Europa.

The images of Ganymede were the closest ever taken of the moon, with a resolution of about 1 kilometer (0.6 miles) per pixel. The images show the moon’s intricate surface features, including craters, ridges, and grooves. Ganymede is the largest moon in the solar system and is thought to have a subsurface ocean of liquid water.

The images of Europa were also high-resolution, with a resolution of about 1 kilometer (0.6 miles) per pixel. Europa is also thought to have a subsurface ocean of liquid water and is considered a prime target for future exploration. The images captured by JunoCam will help scientists better understand the moon’s surface features and geology.

JunoCam is scheduled to capture images of Jupiter’s moon Io during upcoming orbits. Io is one of the four largest moons of Jupiter and is the most volcanically active body in the solar system. Its surface is constantly changing due to volcanic activity and other geologic processes.

Juno will conduct several close flybys of Io in the coming months, allowing JunoCam to capture images of the moon’s surface in high resolution. During the later of these flybys in December, Juno will pass as close as 3500 kilometers (2175 miles) to Io’s surface, allowing JunoCam to capture images with a resolution of up 1 kilometer (0.6 miles) per pixel.

JunoCam at Io

Data used to generate this composite image of volcanic activity on the jovian moon Io was obtained by the Jovian Infrared Auroral Mapper (JIRAM) instrument onboard NASA’s Juno spacecraft during a flyby of the moon on October 16, 2021. JIRAM took the four images over a short time interval to observe volcanic activity on the moon from different view angles. JIRAM data collected over time could provide information on changes to Io’s surface, including the number of active volcanoes or variations in their intensity. JIRAM “sees” infrared light not visible to the human eye. In this composite image, the measurements of thermal emission radiated from the planet were in the infrared wavelength of around 5 micrometers (0.00019685 inches). Credit: NASA/JPL-Caltech/SwRI/ASI/INAF/JIRAM.

The images captured by JunoCam will provide valuable data about the geology and composition of Io’s surface. Io’s surface is covered with colorful, sulfur-rich deposits, and the moon’s volcanoes are some of the most active in the solar system. It will look for surface changes as well as image areas that previous missions did not get a good look at.

Similarly, the Visual Monitoring Camera (VMC) onboard the European Space Agency’s Mars Express spacecraft, launched in 2003, is a low-resolution camera that captures images of the planet Mars and its surrounding environment. The VMC was originally installed to monitor the departure of the UK’s ill-fated Beagle 2 Mars lander, which crashed in 2004. Since then, it has been repurposed as a webcam that provides wide-field color images of the planet during every orbit.

The VMC is a simple camera that uses a single charge-coupled device (CCD) sensor to capture images. It has a field of view of 110° and a resolution of approximately 40 meters (131 feet) per pixel, making it useful for providing context images of the planet and monitoring large-scale changes in the martian atmosphere.

The VMC has been used to capture images of Mars’ atmosphere, including dust storms, cloud formations, and weather patterns. It has also captured images of Mars’ moons, Phobos and Deimos, as well as other objects in the planet’s vicinity, such as comets and asteroids. It has monitored changes in Mars’ polar regions, where changes in the ice caps and surrounding terrain can be monitored over time. The camera has also been used to study the effects of martian seasons on the planet’s atmosphere and surface features.

Like JunoCam, VMC has no science team and is used for outreach and public engagement efforts. Images captured by the VMC have been shared with the public and used in educational materials to promote interest in Mars exploration and space science.

Visual Monitoring Camera image of Mars

This raw image was acquired by the Visual Monitoring Camera onboard Mars Express on August 18, 2023, at an altitude of 9702 kilometers (6029 miles) above Mars, on Mars Express orbit number 24786. Credit: ESA–European Space Agency, BY-SA 3.0 IGO.

Amateur astronomers and citizen scientists also have access to cameras in orbit around Mars and the Moon through their use of the High Resolution Imaging Science Experiment (HiRISE) camera and the Lunar Reconnaissance Orbiter Camera (LROC).

While these instruments are primarily used by professional scientists, the HiRISE and LROC teams offer suggestion pages where anyone can propose locations to image on Mars or the Moon. These suggestions can be made by anyone, including amateur astronomers, and are considered by the HiRISE and LROC teams for future imaging missions.

The HiRISE team at the University of Arizona offers a web-based HiWish tool that allows anyone to suggest a site on Mars for imaging. HiWish is a citizen science project that has been used by thousands of people to suggest imaging targets on Mars. The HiRISE team reviews the suggestions and selects some for further study and potential imaging.

The LROC team at Arizona State University also offers a similar tool, called the Target Request Form, where anyone can suggest a location on the Moon for imaging. The LROC team reviews the suggestions and considers them for future imaging missions.

Amateur astronomers and citizen scientists have made valuable contributions to the study of Mars and the Moon through their use of these suggestion pages. By identifying interesting and important locations for further study, they have helped guide the imaging efforts of these spacecraft and contributed to our understanding of the geology and surface features of these fascinating worlds.

HiRISE image of Samara Valles on Mars

Samara Valles is one of the longest ancient valley systems on Mars. This system traverses more than 1000 kilometers (621 miles) toward the northwest across the heavily cratered southern highlands eroding into the gentle slopes of Terra Meridiani. The valley terminates in the northern lowlands within the Chryse basin where both Viking Lander 1 and Pathfinder are located. The High Resolution Imaging Science Experiment (HiRISE) camera on NASA’s Mars Reconnaissance Orbiter recorded this image on March 4, 2010. The target for this HiRISE observation was a suggestion submitted through the camera team’s HiWish public suggestion program. Credit: NASA/JPL-Caltech/University of Arizona.

The involvement of amateurs in the HiRISE and LROC suggestion pages also highlights the importance of public engagement in scientific research. By involving the public in the scientific process, researchers can gain new insights and perspectives and generate interest and excitement for space exploration and discovery.

Beginning in the early 1990s, planetary science enthusiasts were active on Usenet newsgroups. This soon migrated to Yahoo groups, where a vibrant community formed. Within one planetary science group, image processors began actively sharing their work, both from current missions and from archival data. The latter included imagery using data from NASA’s Planetary Data System as well as work from sleuths who dug through libraries searching for early imagery not in the formal archive.

However, as the group grew, the Yahoo format made having a lot of separate discussions on imagery difficult, so in 2004, Doug Ellison, a software developer and planetary science enthusiast in the UK, created a new board dedicated to the upcoming landings of the Spirit and Opportunity rovers on Mars.

Ellison launched the forum, originally populated mostly with people from the Yahoo group, and it quickly grew in popularity, attracting members from around the world. Soon its scope expanded beyond the rovers and to uncrewed spaceflight in general, which was at the time commonly referred to as unmanned spaceflight, hence the forum’s name:

A strict team of moderators made the forum unique. Crewed spaceflight, speculation about extraterrestrial life, and anything else not related to planetary exploration were not allowed to prevent subject creep. Additionally, nationalist rhetoric, wild unfounded speculation, and unconstructive attacks on specific missions or scientists were banned.

unmannedspaceflight forum threads

This screenshot from the forum shows just a sample of some of the topics being discussed on the site. Monitored by a strict team of moderators, the site provides a unique safe space where science professionals can interact with enthusiasts and amateur image processors without being subject to trolling.

This was to promote civility and to keep trolls from taking over conversations, but it had the unintentional effect of creating a space where professionals could interact with enthusiasts and amateur image processors without the fear of being attacked or associated with negative rhetoric toward other programs. Several participants eventually became involved directly in missions, including Ellison himself, who is now at the Jet Propulsion Laboratory in Pasadena, California, and works on the Curiosity Mars rover team.

Over the years, has become a valuable resource for the space science community, with members sharing insights and analysis related to a wide range of unmanned space missions. The forum has also been involved in a number of citizen science projects, providing opportunities for individuals to contribute to ongoing space missions through their analysis of data and images.

Today, remains an active and vibrant online community with thousands of members from around the world. The forum’s focus on uncrewed space missions and scientific analysis of their data has made it an important resource for the space science community, and its role in promoting public engagement with space exploration and citizen science is widely recognized and celebrated.