The main purpose of this three-year MRI project is to design and build a solar-tracking platform for the NSF/NCAR Gulfstream-V (GV) aircraft, and demonstrate its capabilities by flying two focal plane instruments during the 2020 total solar eclipse across South America. The Airborne Stabilized Platform for InfraRed Experiments (ASPIRE) builds on the success of the Airborne InfraRed Spectrometer (AIR-Spec), turning the GV into a solar-viewing platform for rapid prototyping of solar and atmospheric instruments. By adding a stabilized solar feed to the GV aircraft, the project team will create an airborne platform for infrared remote sensing that will be a valuable resource for both the solar and atmospheric communities. In solar physics, the 20cm feed would enable many applications on and off the solar disk. During the upcoming eclipse mission, for example, the ASPIRE will provide enough throughput to make polarimetric measurements with an airborne version of the Coronal Multichannel Polarimeter (CoMP). The project team will deliver the ASPIRE interface documentation to NSF and NCAR in first quarter 2021. The ASPIRE project will provide research training for at least three REU students at the Smithsonian Institution Astrophysical Observatory (SAO) over its lifetime. The team will involve a Boston-based undergraduate in the ASPIRE development and bring this student to Chile to participate in various EPO activities. Summer test flights in 2020 and 2021 will provide field testing experience for two REU students. Combining a total solar eclipse with the GV research aircraft is an excellent way to captivate public interest. As both the 2019 and 2020 eclipses cross South America, the SAO and NCAR staff will reach out to U.S. Embassy personnel to arrange tours of the unique GV aircraft and give talks on eclipse science.
The main goal of this three-year MRI project is to develop the ASPIRE, which will provide a 20cm diameter solar feed, stabilized to <5 arcsec RMS over a 3 second exposure time. The platform is well-suited for infrared investigations of the Sun, as it can operate above the influence of Earth's atmosphere, and for atmospheric measurements of trace gases obtained by observing sunlight transmitted through atmospheric absorption bands. The ASPIRE will provide broadband visible and infrared transmission from 0.45 to 10 microns, compatible with all of the GV's IR-transmissive viewports. During its 2020 commissioning flight, ASPIRE will feed a 13cm telescope with two complementary focal plane instruments: AIR-Spec (an imaging spectrometer) and a new narrowband imager centered on the AIR-Spec 1.43 micron Si X line. AIR-Spec was designed to characterize five magnetically sensitive coronal emission lines between 1.4 and 4 microns and assess whether they are useful probes of coronal magnetism. It observed all five of its target lines during the 2017 total solar eclipse, detecting the 2.84 micron Fe IX for the first time. The strong Si X line was observed up to 0.6 solar radii from the limb and provided line-of-sight velocity measurements with a resolution of 5 km/s. The larger telescope aperture enabled by ASPIRE will improve the AIR-Spec SNR by a factor of 1.5 compared to its 2019 observation (>6x improvement over 2017), allowing the project team to explore the coronal density and temperature measurements, flows, and oscillations that are on the edge of detection with the current AIR-Spec instrumentation. The Si X context imager will reduce the need for rastering the slit, allowing us to improve SNR by summing 'sit and stare' slit data for more than a minute. The research and EPO agenda of this project supports the Strategic Goals of the AGS Division in discovery, learning, diversity, and interdisciplinary research.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
