Apr. 27, 2016

There are many layers to orchestrating a mission as complex as the Korean U.S. Air Quality (KORUS-AQ) study. Preparing the aircraft and science instruments to come together as one is just a single layer, but it’s extremely important to ensure a safe and successful mission.
NASA’s DC-8 flying laboratory looks like a normal aircraft, but it’s far from it. The highly modified airplane has removable seats, ports, and windows. The onboard electronics have also been modified to support a variety of instruments and racks. Despite the many “holes” in the aircraft filled with instruments, the structure is highly stable and well suited as an airborne laboratory.

Instrument integration work began three weeks prior when the science instruments were shipped to the science lab at Armstrong Flight Research Center’s Hangar 703 in Palmdale. Some of the instruments arrived in pieces and had to be built from the ground up before they were installed on the aircraft. Others arrived fully assembled and only needed to go through power and other system checks before being ready for installation on the plane.
Before loading instruments into the plane, DC-8 lead operation engineer, Matt Berry inspected each of the instruments for “air worthiness” in the science lab. He made sure that each instrument did not omit sparks, smoke, or create other operational hazards that could potentially cause problems during flight.

“Basically, once the instrument is on the plane, it’s not coming off. But we need to make sure it’s safe before we even get to that point,” he said.
While the scientists made sure their instruments were functional, aircraft mechanics removed windows on the aircraft and installed a wide variety of air intake probes. They also installed optical ports into the top and bottom of the plane for laser sensors. After port installation was done, the aircraft looked similar to a porcupine.

Each instrument was then rolled out of the science lab and placed on a large scale that weighed the aircraft for weight and balance requirements. From there, each instrument was loaded onto a lift and carried up to the aft doors of the aircraft.
This part was tricky. Cabin space is limited and the payload of 26 instruments is large by comparison to most missions. So instruments had to be loaded in a specific order, starting with the instruments located at the front of the plane.

Mechanics, avionic techs, data system engineers, and experimenters worked side-by-side to install each instrument without causing delays to the 10-20 instruments in the queue behind them. The experimenters were then free to make sure their instruments were functioning and communicating with the onboard data system.
After instrument installation was completed, the aircraft was moved outside of the hangar to allow the experimenters to calibrate the instruments. The aircraft was then turned back over to the DC-8 crew who performed necessary aircraft maintenance checks on the engines and cabin pressure.

“Our primary job at NASA Armstrong is to make sure that all of the experimenters onboard are safe and can focus on collecting as much data as possible. The DC-8 crew works extremely hard to make that happen,” DC-8 crew chief Corry Rung said.
The final checks happened throughout several short flights. The first, called a “shake flight,” ensured that none of the instrument hardware was loose and functioned correctly. The second two flights were devoted to testing the science instruments themselves.

Meanwhile across the country at NASA’s Langley Research Center, in Hampton, Virginia, the UC-12B King Air was going through a similar integration process. However, because the King Air has a smaller fuel tank and payload capacity, the aircraft cannot make the transit flight to Osan Air Base in South Korea with all of the instruments onboard. So after the science instruments were installed and checked, they were quickly uninstalled and packed into shipping boxes headed to Osan Air Base. Once the King Air aircraft arrives, the crew will reintegrate the science instruments just short of the mission beginning.
With aircraft preparations completed, the next stop is South Korea.

Image:
(Left) NASA’s DC-8 is based at NASA’s Armstrong Flight Research Center Hangar 703 in Palmdale, California.
(Middle) Air intake probes protrude from NASA’s DC-8 flying laboratory in place of normal window ports for the Korean U.S. Air Quality (KORUS-AQ) mission.
(Right) Alan Fried, University of Colorado Boulder, makes an adjustment to the intake for the Compact Atmospheric Multispecies Spectrometer (CAMS) instrument, which will measure formaldehyde and ethane in the atmosphere over South Korea.