NASA WB-57Fs Track 2017’s Great Solar Eclipse

NASA WB-57F with payload, Credit: NASA’s Johnson Space Center/Norah Moran

A high-flying pair of NASA-operated WB-57Fs flew in perfect formation with the sun and moon for close to seven minutes of total eclipse, during the great event of 2017 as it passed across the central United States. The aircraft, which were originally built as jet bombers in the early 1960s, carried telescopes engineered by Southern Research, part of a NASA-sponsored, Southwest Research Institute (SwRI) study of the sun and planet Mercury during the August 21st eclipse. On the ground, observers could only manage slightly more than two minutes of complete overlap.

The equipment aboard the two jets, and the methods used, are described in this Southern Research news release issued before the eclipse:

“A high-definition imaging system developed by Southern Research and deployed on NASA aircraft flying nearly 10 miles above Earth will give scientists a unique look at the Sun’s corona during a rare total eclipse taking place over the United States in August. As a bonus, Southern Research’s Airborne Imaging and Recording System, or AIRS, will provide highly detailed observations of Mercury’s surface and could uncover the first solid evidence of the existence of vulcanoids, a belt of asteroids believed to be circling the Sun.”

WB-57F with AIRS/DyNAMITE turrets, Credit: Amir Caspi/NASA

“To capture this data, Southern Research and its AIRS/DyNAMITE technology are supporting the Southwest Research Institute (SwRI), which won a NASA contract to carry out the mission during the Aug. 21 eclipse. AIRS/DyNAMITE turrets will be mounted on two NASA WB-57 research aircraft, which will fly at 50,000 feet and collect high-resolution video and infrared data throughout the first total solar eclipse occurring over the length of the entire continental U.S. in 99 years.” “NASA is providing the WB-57 aircraft, Southern Research is providing the unique on-board sensors, and Southwest Research Institute is conducting the science,” said Johanna Lewis, director of the Program Management Office in SR’s Engineering Division. …Southern Research will be handling the data collection, and we will be making sure that Southwest Research Institute is getting the best data that we can provide on Mercury and the Sun,” she added.”

Both NASA aircraft departed Houston, Texas and awaited the transit of the eclipse at predetermined points overhead Missouri, after reaching their cruising altitude of 50,000 feet. Flying in tandem but still a number of miles apart, the pair then crossed over the borders of Illinois, Kentucky and Tennessee before finishing their rendezvous with the sun and moon. Their total mission lasted some five hours, at an airspeed of 420 miles per hour.

Part of the advantage of using NASA’s WB-57Fs is that a second cockpit is available for sensor operators or other crew members, allowing for pilots to focus on flying the jets while a human is still in control of the equipment, in this case, the package of airborne telescopes. Additionally, allowing these sensors to be above most of the earth’s atmosphere gave clearer pictures of the subjects, mainly the solar corona and planet Mercury.

Science Data from 52, 922 feet above sea level, Credit: Image courtesy of Southwest Research Institute/NASA/Southern Research

The results of this event are described in this news release by SwRI:

“San Antonio — August 24, 2017 — Two NASA WB-57F research aircraft successfully tracked the August 21 solar eclipse as part of a NASA project led by Southwest Research Institute (SwRI) to study the solar corona and Mercury’s surface.

“The visible and infrared data look spectacular,” said SwRI senior research scientist Dr. Amir Caspi, principal investigator of the project. “We’re already seeing some surprising features, and we are very excited to learn what the detailed analysis will reveal.”

The team began initial analysis of the data gathered during the flights, showing clear images of the Sun’s outer atmosphere and thermal images of Mercury’s surface. Initial results are expected to be released in a few months and presented at the fall meeting of the American Geophysical Union in December 2017.

Total solar eclipses are unique opportunities for scientists to study the hot atmosphere above the Sun’s visible surface. The faint light from the corona is usually overpowered by intense emissions from the Sun itself. During a total eclipse, however, the Moon blocks the glare from the bright solar disk and darkens the sky, allowing weaker coronal emissions to be observed.

“This is the best observed eclipse ever,” said Dr. Dan Seaton, co-investigator of the project from the University of Colorado. “With the results from the WB-57s and complementary observations from space and other experiments on the ground, we have an opportunity to answer some of the most fundamental questions about the nature of the corona.”

The eclipse also provided an opportunity for scientists to study Mercury, which is notoriously difficult to image because of its proximity to the Sun. “The infrared images of Mercury were much brighter than we originally expected,” said Caspi. Using infrared observations in near darkness through very little atmosphere, the team received data enabling it, for the first time, to attempt to estimate the surface temperature distribution over the planet’s night side. “It will be incredibly interesting to dig into these data,” said Dr. Constantine Tsang, SwRI senior research scientist and a co-investigator on the project.

The team used stabilized telescopes with sensitive, high-speed, visible-light and infrared cameras aboard the research aircraft from an altitude of 50,000 feet, providing a significant advantage over ground-based observations. These are the first astronomical observations for the Houston-based WB-57Fs. Southern Research, of Birmingham, Ala., built the Airborne Imaging and Recording Systems (AIRS) and worked with the scientific team to upgrade its DyNAMITE telescopes onboard the planes with solar filters and improved data recorders and operating software.

Flight Crew, Credit: via Southwest Research Institute, courtesy of NASA

“The pilots, instrument operators, and engineers did a phenomenal job getting us exactly the data we asked for,” said Caspi. “Achieving this quality of measurement required an enormous effort and precise timing, and everyone hit their mark exactly. I am honored to be part of such an exceptionally talented and professional team, and grateful for everyone’s dedication and hard work.”

The SwRI-led team includes scientists from the University of Colorado, the National Center for Atmospheric Research High Altitude Observatory, and the Smithsonian Astrophysical Observatory, as well as international colleagues at Trinity College Dublin in Ireland and the Royal Observatory of Belgium.”

NASA has operated a pair of 1963-vintage Martin/General Dynamics WB-57Fs since the late 1960s after the U.S. Air Force retired their fleet. Originally built as RB-57F reconnaissance and air sampling aircraft, they were much-modified Martin B-57B bombers, which were license built versions of the English Electric Canberra bomber. Recently, a third WB-57F has been pulled from the AMARG storage facility in Tucson, and flew for the first time in forty-one years in 2013. At least four more airframes are still held in storage at AMARG as of the summer of 2017, presumably for spares or even more return-to-duty aircraft.

NASA926 file photo – this was one of the WB-57Fs that flew the Solar Eclipse mission with the AIRS/DyNAMITE  sensor package