Mention “space weather” to most people, and they’ll look at you funny. Maybe they’re thinking of John Belushi’s portrayal of Captain Kirk in the old “Saturday Night Live” Star Trek skit.
Yet space weather is real—and no laughing matter.
What it is
Space weather is electromagnetic stuff happening in space—usually involving the sun—that can affect us here on Earth. That can include solar flares, solar storms, coronal mass ejections (CMEs) and solar wind. It all increases the radiation content in space, which in turn can affect satellites, power grids and radio propagation.
“The sun can do a lot of good stuff for us,” said Ron Hranac, a technical leader at Cisco and CT’s senior technology editor. “But it can also do some interesting and some nasty things, like spit out huge storms that can have a pretty severe impact on things here on Earth.”
Depending on the type of solar event, the “stuff” in question can be protons, electrons and/or plasma—that is, ionized gas, which contains ions and electrons.
“A solar flare is protons at pretty much every energy you can think, whether it’s radio, whether it’s X-ray, gamma ray, ultraviolet,” said Doug Biesecker, a scientist with the National Oceanic and Atmospheric Administration’s Space Weather Prediction Center.
“A coronal mass ejection is literally exactly that—it’s an ejection,” Biesecker continued. “Here we’re talking about plasma from the sun and the magnetic field associated with it. It erupts at thousands of kilometers per second headed out into space.”
If fast enough, he said, the ejection could develop a leading-edge “shock” conducive to proton acceleration, resulting in energy propagating “almost at the speed of light.”
Those high-speed protons are a threat to satellites, with the potential to cause bit flips in onboard computers as well as confuse the birds’ navigation systems.
“In single-event upsets, you get a proton coming through, and it can cause a computer to misread a bit, a one instead of a zero,” Biesecker said. “If the computer misreads that, who knows what the computer’s going to do.”
Regarding nav systems such as Star Tracker, Biesecker said that the problem is not the occasional proton event, but rather big events that saturate the system and disorient the bird.
Excess electrons can build up an electrostatic charge on a satellite’s surface, much like the static electric charge you get from shuffling your feet on carpet.
“Eventually that charge has to discharge,” Biesecker said. “Discharge in the wrong place, and you’ve killed a critical component.”
Geostationary satellites—those are the ones from which many cable operators receive programming—are vulnerable to severe space weather. In the worst case, it can take out a transponder or entire satellite.
“Telstar 401 in 1997, space weather, it was gone for good,” Biesecker said. “There are instances of satellites completely killed by space weather.”
Power grids and railroad tracks, both essentially being very long conductors, are also at risk. A big solar flare in 1989 caused power outages in Canada that affected about 6 million people.
“There are surge currents, if you will, induced in those long conductors,” Hranac said. “These surges can, if they’re severe enough, damage electrical equipment—transformers, substations and other things.”
According to a recent press release from the NOAA, an 1859 solar storm shorted out telegraph wires, causing fires in North America and Europe, sent readings of Earth’s magnetic field soaring, and produced extraordinarily bright northern lights. A recent report by the National Academy of Sciences indicated that if a storm that severe occurred today, it could cause $1-2 trillion in damages the first year and require four to 10 years for recovery.
Protecting communications satellites from space weather generally involves hardening the bird when it’s built and monitoring once it’s in orbit, said Toby Nassif, VP of satellite operations and engineering for Intelsat.
“A lot of the spacecraft, especially the newer ones more so than the older ones, are designed to try to shield the proton charges coming through that would create those issues,” Nassif said. Other counter measures, he added, include layered components, redundant or self-correcting software and techniques for discharging electrostatic charges.
Otherwise, there’s little a satellite operator can do in inclement space weather. It’s mainly a matter of watching and applying error correction.
“We’re more alert to watch for any type of anomalous activity,” Nassif said. “There’s no protective actions we can take. You can’t say, ‘Raise the shields, photon torpedoes.’”
Some satellites, such as some NASA birds, can be maneuvered, turned, or even put into standby mode to protect them during space storms. But geostationary communications satellites have to just stand there and take it.
“Our satellites are providing 24/7 communication coverage for our customers, so we don’t have the luxury of pointing away or doing something like evasive maneuvers,” Nassif said.
Since actual protection is limited, the next best things are redundancy and prediction.
“Most of our transponders have spares, so if we lose a transponder, we would roll in the spare,” Nassif said. “If we lost an entire bird, we do have … a couple of spare satellites that we can bring into service.”
And forewarned is forearmed. NASA recently put three satellites up to keep an eye on the sun.
“They’re 90 degrees apart in solar orbit, and they’re in an orbit that’s synchronized with the Earth, but it’s actually orbiting the sun,” said Dom Stasi, CTO of TVN Entertainment, which delivers video on demand (VOD) content via satellite. “They can look at and see a coronal mass ejection and determine its speed and report that back immediately.”
Back on earth, power grids pose a separate challenge.
“You can’t ground the electrical conductors themselves,” Hranac said. “If you try to ground a 230,000-volt transmission line, it’s no longer a transmission line.”
The cable plant itself, though, should be relatively safe.
“Directly on the fiber optic or low-voltage wire, I don’t think there’s any issue,” Biesecker said.
Backup and restoration
While space weather can smoke a satellite, such events are rare. Because the sun is a sphere, relatively few solar events directly face the Earth, so most dissipate out into other parts of space. More common are minor glitches. Still, losing the signal for whatever reason can cause a scramble.
Content providers and aggregators such as HBO and TVN Entertainment typically have detailed backup plans and contracts in place with the satellite operators. Backup plans can range from switching to a different transponder or bus on the same satellite to moving to a different satellite altogether, said Stasi.
“There are several levels of backup in place, some more arduous than the others, but they accommodate a temporary failure, a transponder failure, a bus failure, or a complete spacecraft failure,” he said.
What to do
Those backups are there for a reason.
“Since the ’70s … we (TVN) haven’t lost any birds or transponders, or even service—yet,” Stasi said. “But it appears to be an inevitability. Sooner or later, it’ll happen.”
Even without catastrophic failures, it’s still wise to be prepared, Hranac said. Know the backup transponders and satellites for your programming and whether your dishes have a clear line of sight to them. Be aware of any frequency changes that may be necessary—sometimes no change is needed, but other times it is.
“There probably should be some kind of Plan B in place at the system level, or certainly at the corporate level of a cable operator,” he said. “It may be one of those low priority things, but discuss it.”