Newswise — Workers at the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) just completed moving the famous array’s radio-telescope antennas into a new configuration, something they’ve done routinely for four decades.
However, this time was dramatically different. Each move of a 230-ton VLA antenna is a complex, multi-step operation requiring close coordination among multiple team members — but now in the era of COVID-19 and social distancing.
“The National Radio Astronomy Observatory (NRAO) is here to serve the scientific community, and to do that we had to be able to complete this configuration change. That meant figuring out how to do it while keeping our staff safe from the virus,” NRAO Director Tony Beasley said.
Throughout the COVID-19 pandemic, NRAO has continued to operate the VLA and the Very Long Baseline Array (VLBA), a continent-wide radio telescope system. Until early June, the VLA was operated with only a skeleton staff, with most employees remaining at home.
“We called out people a few times to fix equipment failures, but stopped our regular maintenance days at the VLA,” said Mark McKinnon, NRAO’s Assistant Director for New Mexico Operations. “Since our far-flung VLBA sites already have minimal crews, we could continue regular maintenance for those,” he added. “The array operators for the VLA and the VLBA, along with the VLBA site technicians, did a great job of keeping everything running during this period.”
However, a backlog of VLA maintenance items kept building. In addition, regularly reconfiguring the VLA antennas is a vital part of the VLA’s scientific program. Astronomers who use the VLA depend on the configuration changing to accommodate their observing needs.
“We had to do the reconfiguration, but we also had to protect the crews from COVID-19,” McKinnon said.
That requirement meant that “We had to examine all our procedures — to avoid close contact, to mitigate it when it’s inevitable, and even to provide COVID-safe transportation for crew members,” said Mike Romero, deputy division head for the VLA’s Engineering Services.
Each of the VLA’s 27 giant dish antennas sits on one of 72 sets of concrete piers, spaced out along the three arms of the “Y”-shaped array. Each set of piers also has connections for electrical power and for the fiber-optic system that carries the antenna’s data back to the VLA’s control building.
Changing the spacing between antennas changes the resolving power, or ability to see fine detail, of the VLA. A regular cycle of different-sized configurations provides a range of resolving power suitable for different types of observations. The configuration schedule is published well in advance to allow astronomers to plan their observations.
Antennas are moved using specially-designed diesel-hydraulic transporter vehicles, capable of lifting an antenna off its concrete piers, providing power to the antenna during the move, and carrying the antenna along a double set of railroad tracks to a different set of piers. Intersections between the main rail line of each arm of the “Y” and the short spurs that go to each set of piers are 90-degree intersections. To make the 90-degree turn, the transporter is positioned precisely at the center of the intersection, lifted on hydraulic jacks, and wheel assemblies, called “trucks,” at each corner are rotated on turntables to line up with the perpendicular set of tracks.
The major steps of moving an antenna include disconnecting the power and fiber connections, unbolting it from the piers, lifting it off the piers, moving to the intersection, turning the wheels 90 degrees, moving to the next intersection, turning the wheels again, moving to the destination set of piers, bolting the antenna down again, and connecting it to the fiber and power at the new location. The job is done with a team of six.
Every part of this process now must be done incorporating COVID-19 protections.
This presented “a very large learning curve for everybody,” according to Safety Officer Helen Schledewitz-McGinnis.
The starting point was to write a comprehensive, step-by-step work plan for the whole process. This was a collaborative process involving management, the safety officers, and the workers who would do the job.
“We asked the workers to participate in the work plan process,” Schledewitz-McGinnis said.
That was a great help, Romero said, because “We know they do their jobs, but we don’t always know how.”
Once the plans were completed, the crew and the safety officers had a pre-job meeting to go over the new procedures in detail.
The resulting plans incorporated changes that affected nearly every part of the task.
The starting point was personal protective equipment (PPE) and sanitizing supplies. The required PPE includes face masks and gloves, in addition to the usual hard hats, safety glasses, and steel-toed footwear. For sanitizing, each worker is issued alcohol wipes, soap, water, paper towels, and a trash bag.
The new rules require that everyone sanitize tools, instruments, and work spaces before and after each use. “You touch it you clean it.”
Crew members no longer share tools. “We used to just throw all the tools in a pile, but now they’re color-coded for each individual,” said antenna mechanic Kelly Greene.
The requirement for social distancing changed several procedures. When checking out the antenna, multiple groups used to be on it at the same time, but now only one group at a time is allowed. At the end of the move, to check all the antenna’s systems, “we kept the same individual each time to check after the power was restored,” Greene said. That person then sanitized the antenna on their way down from it.
Social distancing also meant that crew members accustomed to jumping in to help each other now have to “let the one guy do his job,” Romero said.
At various stages of the moving process, crew members are stationed around the transporter to watch for problems. Because of the noise from the transporter, they previously used whistles to signal a problem, but whistles and face masks don’t work well together. The workers now have canned-air horns.
To maintain social distancing, a new rule requires that only one person be in a vehicle at a time. As the transporter moves along the rails, its operator and a supervisor occupy separate cabs in the transporter. The other crew members are in individual vehicles. At the end of the day, the transporter is left in the field to be ready for the next day’s work, and the crew returns to their building.
“Generally, we used to all ride together,” Greene said. At the end of the first move, the crew suddenly realized that the new rule meant that those who had been aboard the transporter didn’t have a ride. Fortunately, it was a relatively short distance and they could walk.
Now, at the end of the day, a pair of utility task vehicles (UTVs) is brought to the transporter on a trailer for those crew members to drive back.
Despite all the new rules, the antenna reconfiguration was “actually completed within the allocated time,” Romero said.
Safety Officer Aspen Doan-Isenhour added that “It went very well.”
“I don’t see how it could have gone more smoothly,” Greene said.
“A normally routine operation like moving the antennas becomes an undertaking during COVID-19,” said Joe Pesce, NSF Program Director for NRAO. “Thanks to the dedication of the professional crew at NRAO, even in these unprecedented times science observations can continue, with adjustments necessary to ensure the staff’s safety.”
Antenna moves are not the only tasks affected by the COVID-19 requirements.
COVID-19 now “affects everything we do,” Romero said, adding that adapting to the new requirements still is an ongoing process. Every task must be revised.
“Everything that pops up, we have to write something first,” Romero said. Before doing a task, crews “have to wait for a procedure to be written.”
The pandemic has meant, Romero explained, that waiting to write work plans is “a different mindset that we have to get into.”
“It’s a little slower, but we’re getting it done,” he said.
Schledewitz-McGinnis said she worked on 100 work plans in four weeks. The safety officers, the workers, and management all worked together — “Everybody wants to help,” she said.
“In 25 years in health and safety, I’ve never seen more teamwork.”