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Space science done by remote control

The flags of the nations involved in the international space station light up workstations in NASA's high-tech Payload Operations Center, at Marshall Space Flight Center in Huntsville, Ala.
The flags of the nations involved in the international space station light up workstations in NASA's high-tech Payload Operations Center, at Marshall Space Flight Center in Huntsville, Ala.NASA

With the crew of the international space station reduced from three to two because of shortages of supplies, and the two remaining men now overloaded with extra work preparing for a repair spacewalk later this month, one might get the impression that the multibillion-dollar orbital outpost’s sophisticated science gear is gathering space dust.

NASA’s official timelines and schedules certainly contribute to that impression: “Science operations” are allocated between 10 and 15 hours per week, out of more than 100 hours of available crew time. And during busy weeks, they sometimes don’t even get that much.

So is space-based research a bust? Has building and maintaining the station come to consume so much time that the promised contributions to science have been lost?

Fortunately, there’s a hidden factor in this equation, a phantom “third crewman” who keeps the science gear functioning and productive 24-7, whether the onboard astronauts are paying attention or not. Overlooked in the sense of gloom and doom over the struggling project is the remarkable revolution in teleoperational capability — what used to be called “remote control” — brought about by specific design features of this new station.

The first ‘telescience’ space station
“The move to telescience — that’s one of the most wonderful things we can do on the station,” said Merri Sanchez, a NASA official in Houston who has served as “increment manager” for several of the recent expeditions.

“We have payloads continuously operating,” she told, whether the crew is present or not, and whether the station is in radio contact with Earth or not. 

Rickey Cissom, manager of the Payload Operations Center at NASA’s Marshall Space Flight Center in Huntsville, Ala., explained the impressive capabilities of the communications links.

“The technology is leaps and bounds ahead of early shuttle and Apollo,” he said. Downlink last year was 50 megabits per second through a relay satellite network — compared with 1 to 2 megabits per second for a commercial broadcast TV channel. The operations center's downlink traffic included data and up to four television channels. And new ground processing software brought online a few months ago has tripled the rate.

As a result, experiments can be operated successfully and genuine research can be conducted.

Doing science without the crew
An example is a project called Pore Formation and Mobility Investigation, or PFMI. The experiments use a transparent modeling material, succinonitrile (either alone or mixed with water) to observe how bubbles form, move and interact during melting and directional resolidification. Results so far have revealed features of the process that show promise to improve industrial production methods.

“To set up the experiment, the glovebox controllers [on Earth] do the videotaping, and we control the experimental hardware,” glovebox investigator Dick Grugel told “We can change the processing parameters in real time — for instance, sample temperature, or the rate we’re [moving] the sample. We have visuals. We have two cameras in the experiment hardware, we are watching our sample anywhere from 1X to 40X magnification, and we can move the camera up and down the samples.”

This is all done under remote control, he explained: “The crew is usually off doing something else.” But the ground team pays full attention during the entire process. “We usually run 10 to 12 hours, then the sample is stored for possible reuse and eventual return. The more important part is the video of processing in a microgravity environment,” he said.

Operating out of the Huntsville facility, Grugel said that it seems as if “the device could be in the building next door.” There is only a slight delay. “We send a command and see a response in about five seconds,” he said.

“Distance and delay isn’t an impact," Grugel said. "The biggest impact is the breaks in the signal.” His main complaint has to do with how often — and for how long — the real-time link is interrupted. The link is supposed to be practically continuous, but it’s far from that goal.

“We didn’t get 100 percent viewing — we get 20 or 30 minutes an hour in different sized segments,” Grugel explained.

Roots of the problem
Payload operations manager Cissom explained what’s currently the problem: “It’s a function of blockage of vehicle structure. When the trusses are completely built out, and the antenna is moved, we’ll approach 80 percent coverage. The theoretical maximum is 92 percent.”

The antenna is atop what NASA calls the “Z1 truss,” right on the roof of the Destiny laboratory module, and temporarily there is a set of arrays and radiators directly above it. Those structures are to be moved out to the end of a new array, which will be added once shuttle flights resume.

While the outages are unavoidable, they are not unpredictable.

“They have these very well scheduled, long in advance,” Grugal pointed out. “Five minutes on, nothing for 10; one minute on, then 15 off, then 20 on. … There’s no obvious pattern.”

The blockage affects only continuous video monitoring of these experiments.

“Core systems telemetry and all vehicle commanding are sent at a low data rate over [another radio link],” Cissom explained, “and it has coverage in the 70s to 80s percentage.”

No data are lost during the blockage periods, Grugel added: “The video is continuous on the station, you can dump that later.”

Using the current communication links — and despite the interruptions, they are a vast improvement over all previous space stations — payload operators have extended their Earthside networks to provide links between actual scientific investigators and their hardware in space.

“We upgraded our control center to allow payload developers to access and command from their offices, from standard laptops,” Cissom explained. “It’s a fully Internet-based system with password protection and encryption, and meets all NASA security requirements,” and it's been in operation since early 2001.

From office desk to outer space
“We’ve had 46-47 remote sites — at any one time, 20 to 30 are involved in experiments,” Cissom said. The network is now being upgraded to handle 200 remote sites. As an example, on one experiment rack (called “Express-1”) there are eight subracks, and each one could be operated from any of the ground sites. Another rack, the Human Resource Facility, is controlled from NASA’s Johnson Space Center in Houston, which distributes live data to 20 to 30 principal investigators at remote sites.

All these users are not jamming the bandwidth simultaneously. “We develop the ‘command plan’ to spread the commands out,” Cissom explained. “The most sites in operation simultaneously has been three or four, since we try to schedule around conflicts.”

The resulting operational mode for the station’s science experiments does not call for the crew to monitor and control and experimental processes continuously. Instead, they assist in start-up and adjustments and close-out, as well as troubleshooting. “We don’t have the luxury of calling them up every 20 minutes for an adjustment,” Grugal admitted. “But a few times we had to ask them to check out a strange reading.”

So even if science gets only a small fraction of the scheduled crew time, it’s the critical events that enable ground controllers to teleoperate the equipment. These events include, in Sanchez’s words, “all preparation, procedures review, gathering tools, all actual research activity like changing out samples, all cleanup.”

As a result of the teleoperations capability, experienced operators who have extended their senses and their controllers onto the station often almost feel as if they are there.

“We see ourselves as the third crewmen on orbit,” Cissom told “And we’re running 24 hours a day with remote commanders.”