On the launch pad at White Sands Missile Range, the 10-foot section of a NASA sounding rocket housing scientific instruments designed and built by a team at Montana State University to observe explosive events in the sun’s atmosphere was encased in Styrofoam to shield it from the New Mexico sun.
Graduate student Catherine Bunn monitored the instruments’ temperature, chilling them as needed with liquid nitrogen. Fellow graduate students Roy Smart and Jacob Parker, along with Charles Kankelborg, a professor in the Department of Physics in the College of Letters and Science, made last-minute checks.
But would the rocket fly?
It was late September. The launch had originally been scheduled for Aug. 20, but a critical vibration test shook a screw loose and left a mirror out of alignment.
“They were essentially trying to rattle the payload apart and more or less succeeded,” said Kankelborg. “As much as we dread vibration tests, they are a necessary test to ensure the payload is ready for launch. It is much better to break a screw on the ground than in flight.”
So, the team shipped their camera assembly to NASA’s Marshall Space Flight Center in Huntsville, Alabama, for repairs. They converged back at White Sands at the beginning of September and again readied for launch.
But on Sept. 24, the clock counted down to zero on the second launch attempt, the ignition key turned, and — nothing happened. An open circuit fault in the ignition system pushed the launch back yet again.
Third time was the charm, however, for the first flight of ESIS, an Extreme ultraviolet Snapshot Imaging Spectrograph built by MSU’s Space Science and Engineering Laboratory and the Marshall Space Flight Center. Its predecessor MOSES, or Multi-Order Solar Extreme ultraviolet Spectrograph, was also on board.
While the ESIS and MOSES programs represent huge potential for future development as a primary instrument on a future satellite, the sounding rocket missions are only a part of the scope of the Space Science and Engineering Laboratory’s work, according to David Klumpar, a professor of physics and director of the laboratory. The interdisciplinary laboratory was founded in 2000 and has about four active projects with launches expected in the next few years. Those include tiny satellites between 2 and 15 pounds that will end up in orbit around the Earth and giant 1000-pound instrument payloads for large balloons that reach the edge of the atmosphere. Teams for each project include both undergraduate and graduate students.
“We work proactively to have students at all levels involved in what it takes to design and build and operate hardware for research in space,” Klumpar said.
This is the third time an MSU team has worked with NASA scientists at White Sands. The previous two launches in 2006 and 2015 carried only versions of MOSES.
“We just build the instrument,” Kankelborg said before the launch. “They’re going to launch it into space and point it at the sun.”
ESIS observes the sun’s atmosphere, specifically looking for explosive events in the solar transition region at the roots of the corona. The explosive events are powered by magnetic reconnection, where magnetic fields within a plasma rearrange and discharge heat and kinetic energy. This is the same process behind solar flares — extreme and sudden energy releases Kankelborg likens to nuclear bombs, if one were to multiply their power by a “very big number.”
While the team can’t plan for solar flares, even with a so-called quiet sun, free of sunspots or visible prominences, the smaller explosive events are common. On its first launch in February 2006, the MOSES instrument detected 41 explosive events in a five-minute window, Kankelborg said. And that was also a quiet sun.
“The magnetic network is always moving around, always changing,” Kankelborg said. “As the magnetic fields move around and crash into each other, they create little explosive events. They can be Earth-sized and reasonably powerful but are not spectacular like solar flares.”
The explosive events form jets of gas that emit light. Studying the images from a spectrograph frame by frame allows the team to measure the velocity of that gas through shifts in the light’s wavelength.
With the gathered data, the team will seek insights into how the sun stores and releases energy through magnetic reconnection. Large energy releases on the sun can hurl clouds of magnetized plasma into space. When that plasma nears Earth, it causes some beautiful phenomena, such as the northern lights. However, it could also expose flight crews to radiation or interrupt satellite signals.
For the Sept. 30 launch, ESIS and MOSES were a roughly 600-pound payload on the NASA sounding rocket, which was otherwise loaded with equipment to control its trajectory, aim the instruments at the sun and bring the rocket safely back to Earth. Sounding rockets are suborbital rockets that carry instruments into outer space for scientific research but do not go fast or high enough to orbit the Earth.
That’s not to say they’re slow. Unlike rockets carrying people, the sounding rockets launch at incredible speeds, producing G-forces that would be dangerous to humans. The rocket’s engines carried the instruments 164 miles above the surface of the Earth on the 15-minute flight, creating about 12 Gs of force off the launch pad. After the rockets burnt out and separated from the payload, a door opened at the end of the experiment for the five-minute data collection window.
To ready for the launch, grad student Parker focused on optics, testing the alignment and focus of ESIS and MOSES over and over. Smart was focused on the software and data collection. He designed a powerful neural network to take the data from the 2-D detectors and process it into 3-D images.
The debut of ESIS looks to be a success in terms of sun data collection, Kankelborg said. Initial images from MOSES didn’t show solar features, a possible indicator of shutter failure, but what it did capture revealed something unexpected. High energy electrons above Earth's atmosphere passed easily through the aluminum skin of the experiment section to the MOSES cameras, leaving bright spots and tracks on the otherwise dark images.
“High energy electrons like that are normally associated with the Van Allen radiation belts,” Kankelborg said. “They are commonly detected in sounding rocket launches from Alaska or other high latitude locations. It is exceedingly rare to observe them as far south as New Mexico.”
Two of MSU’s Space Science and Engineering Laboratory satellites in orbit since early 2015 collect data on these high energy electrons from an altitude about 150 miles above MOSES. According to Klumpar, these satellites may have serendipitously been in position to directly measure the electrons that caused the tracks to appear on the MOSES camera images.
Much of how the sun works remains a mystery, Smart explained, but the local star has long been a source of advancement in physics.
“It’s an awesome laboratory within our view,” he said.