On May 5, 2017, NASA successfully launched RAISE, its Rapid Acquisition Imaging Spectrograph Experiment. The target of this mission was the center of the solar system—the sun. RAISE snapped an astounding 1,500 pictures of the sun in a five-minute photo shoot (it had to be sure it caught the sun’s good side). The RAISE mission’s goal is to capture and analyze the lightning-fast changes that take place on the sun that result in solar flares and other activities scientists don’t yet fully understand.
The spectrograph traveled 184 miles into the atmosphere on a sounding rocket, a type of rocket NASA has used for over 40 years for data-gathering missions. Unlike rockets used to launch astronauts, ISS cargo, or satellites, sounding rockets generally spend 15-20 minutes traveling relatively low trajectories, and they move more slowly to allow the onboard instruments the best opportunity to gather and process images and information. These instruments have only five or six minutes to collect data, so perfect execution is key to success. Because they’re not in the air for very long and don’t require the same thrust as orbital rockets, sounding rockets are cost-effective and efficient.
GIF of RAISE spin-balance test. Credit: Amir Caspi, Southwest Research Institute/Joy Ng, NASA’s Goddard Space Flight Center
While RAISE is not the only instrument focused on the sun (NASA’s Solar Dynamics Observatory and Solar Terrestrial Relations Observatory both constantly observe it), the complexities of our star warrant more in-depth examination, particularly because conditions on the sun change so quickly that they’re difficult to observe. RAISE’s principal investigator Don Hassler explains that because “dynamic processes happen on all timescales” on the sun, an instrument such as RAISE offers unparalleled data: “With RAISE, we’ll read out an image every two-tenths of a second, so we can study very fast processes and changes on the sun. That’s around five to 10 times faster than comparable instruments on other sounding rocket or satellite missions.”
RAISE in the clean room. Credit: NASA
The data collected by RAISE creates a spectrogram, which splits the sun’s light into different wavelengths, which scientists can then study to determine how solar magnetic energy and the movement of solar material work and how solar flares form. Friday’s mission is the third for RAISE—this time around, the instrument has updated software, detectors, and diffraction grating, which is what separates the wavelengths. After it finished its mission, RAISE parachuted to the ground, and it will no doubt be updated and used again.
NASA is currently in the process of recovering RAISE’s data and will release analyses after researchers have a chance to analyze the 1,500 images it harvested. We’ll soon know what insights this mission contributed to our understanding of how our source of light and energy works and what accounts for its solar eruptions.