When we think of space satellites that assist with communications, weather monitoring and GPS here on Earth, we likely picture them as being quite largemany are as big as a school bus and weigh several tons.
Yet there's a class of smaller satellites that's growing in popularity. These miniaturized satellites, known as nanosatellites or CubeSats, can fit in the palm of your hand and are providing new opportunities for space science.
"CubeSats are part of a growing technology that's transforming space exploration," said David Pierce, senior program executive for suborbital research at NASA Headquarters in Washington. "CubeSats are small platforms that enable the next generation of scientists and engineers to complete all phases of a complete space mission during their school career. While CubeSats have historically been used as teaching tools and technology demonstrations, today's CubeSats have the potential to conduct important space science investigations as well."
CubeSats are built to standard specifications of 1 unit (U), which is equal to 10x10x10 centimeters (about 4x4x4 inches). CubeSats can be 1U, 2U, 3U or 6U in size, weighing about 3 pounds per U. They often are launched into orbit as auxiliary payloads aboard rockets, significantly reducing costs.
Because of the smaller payload and lower price tag, CubeSat technology allows for experimentation. "There's an opportunity to embrace some risk," said Janice Buckner, program executive of NASA's Small Innovative Missions for Planetary Exploration (SIMPLEx) program. "These mini experiments complement NASA's larger assets."
Another advantage of the "smaller is bigger" concept is it's more inclusive. The low cost and relatively short delivery time from concept to launch typically 2-3 years allows students and a growing community of citizen scientists and engineers to contribute to NASA's space exploration goals, part of the White House's Maker Initiative. By providing hands-on opportunities for students and teachers, NASA helps attract and retain students in science, technology, engineering and math disciplines, strengthening NASA's and the nation's future workforce.
This inclusiveness also applies to geography. In 2014 NASA announced the expansion of its CubeSat Launch Initiative, with the goal of launching 50 small satellites from 50 states within five years. To date NASA has selected CubeSats from 30 states, 17 of which have already been launched. Two more -- Alaska and Maryland -- are slated to go to space later this year, including the first ever CubeSat launched by an elementary school.
In April 2015 the SIMPLEx program requested proposals for interplanetary CubeSat investigations, with a panel of NASA and other scientists and engineers reviewing 22 submissions. Two were chosenone led by a postdoctoral research scientist and the other a university professor. NASA Headquarters, Planetary Science Division, also selected three technology developments for possible future planetary missions: one to expand NASA's ability to analyze Mars' atmosphere, one to investigate the hydrogen cycle at the moon and one to view a small near-Earth asteroid. Each selected team will receive one year of funding to bring their respective technologies to a higher level of readiness. To be considered for flight, teams must demonstrate progress in a future mission proposal competition.
The CubeSat investigations selected for a planetary science mission opportunity are:
Lunar Polar Hydrogen Mapper (LunaH-Map), a 6U-class CubeSat that will enter a polar orbit around the moon with a low altitude (3-7 miles) centered on the lunar south pole. LunaH-Map carries two neutron spectrometers that will produce maps of near-surface hydrogen. LunaH-Map will map hydrogen within craters and other permanently shadowed regions throughout the south pole. Postdoc Craig Hardgrove from Arizona State University (ASU), Tempe, Arizona, is the principal investigator. ASU will manage the project.
CubeSat Particle Aggregation and Collision Experiment (Q-PACE) is a 2U-class, thermos-sized, CubeSat that will explore the fundamental properties of low-velocity particle collision in a microgravity environment, in an effort to better understand the mechanics of early planet development. Josh Colwell from the University of Central Florida (UCF), Orlando, Florida, is the principal investigator, and UCF will manage the project. The proposals selected for further technology development are:
The Mars Micro Orbiter (MMO) mission, which uses a 6U-class Cubesat to measure the Martian atmosphere in visible and infrared wavelengths from Mars orbit. Michael Malin of Malin Space Science Systems, San Diego, California, is the principal investigator. Hydrogen Albedo Lunar Orbiter (HALO) is a propulsion-driven 6U-class CubeSat that will answer critical questions about the lunar hydrogen cycle and the origin of water on the lunar surface by examining the reflected hydrogen in the moon's solar wind. The principal investigator is Michael Collier of NASA's Goddard Space Flight Center, Greenbelt, Maryland.
Diminutive Asteroid Visitor using Ion Drive (DAVID) is a 6U-class CubeSat mission that will investigate an asteroid much smaller than any studied by previous spacecraft missions and will be the first NASA mission to investigate an Earth-crossing asteroid. Geoffrey Landis of NASA's Glenn Research Center, Cleveland, Ohio, is the principal investigator.
"These selections will enable the next generation of planetary scientists and engineers to use revolutionary new mission concepts that have the potential to return extraordinary science," said Buckner. "CubeSats are going to impact the future of planetary exploration."