NASA probes will study potentially dangerous "space weather"

SpaceX launched twin satellites for NASA Wednesday that will study how the electrically-charged solar wind interacts with Earth's magnetic field, creating constantly changing and occasionally dangerous "space weather" affecting satellites, electrical grids and other critical systems.

The identical TRACERS satellites will operate in the magnetosphere, "the region around our Earth that is dominated by the planet's magnetic field, and it protects us from the stellar radiation and really from everything else that's going on in space," said Joseph Westlake, director of NASA's solar physics division.

"What we will learn from TRACERS is critical for the understanding and eventually the predicting of how energy from our sun impacts the Earth and our space and ground-based assets, whether it be GPS or communication signals, power grids, space assets and our astronauts working up in space.

"It's going to help us keep our way of life safe here on Earth."

Hitching a ride to space along with TRACERS atop a SpaceX Falcon 9 rocket were five other small satellites, including one that will use a new "polylingual" terminal to communicate with multiple other satellites and space probes using different protocols.

Another will collect data about how much solar energy Earth absorbs and reemits into space, known as the "radiation budget," and another that will focus on how high-energy "killer electrons" are knocked out of the Van Allen radiation belts to rain down into the atmosphere.

Two other small satellites were aboard, including an experimental "cubesat" that will test high-speed 5G communications technology in space and another built by an Australian company carrying five small satellites to test space-based air-traffic management technology that could provide aircraft tracking and communications anywhere in the world.

The mission got underway at 2:13 p.m. EDT when a SpaceX Falcon 9 rocket roared to life at launch complex 4E at Vandenberg Space Force Base on the California coast. The launching one day late because of a regional power outage Tuesday that interrupted air traffic communications over the Pacific Ocean near Vandenberg.

The second time around, the countdown ticked smoothly to zero and after boosting the upper stage and payloads out of the lower atmosphere, the first stage peeled away, reversed course and flew back to a landing near the launch pad.

A few seconds later, the upper stage engine shut down to put the vehicle in its planned preliminary orbit. The two satellites making up the primary TRACERS payload were deployed about an hour-and-a-half after launch.

Two of the other smallsats were to be released earlier in a slightly different orbit, with the remainder following TRACERS a few minutes later.

TRACERS is an acronym for Tandem Reconnection and Cusp Electrodynamics Reconnaissance Satellites. The twin spacecraft, built by Boeing, will fly in tandem in the same orbit, 10 seconds to two minutes apart, helping researchers precisely measure rapid changes indicating how the solar wind "couples" with Earth's magnetic field.

"So the Sun is a burning, fiery ball of plasma and as it burns, it blows off an exhaust that we call the solar wind, it's a plasma, and that's always streaming from the sun towards the Earth," said David Miles, principal investigator at the University of Iowa.

"And sometimes, the magnetic field of the Earth basically stands it off in the same way that if you have a rock in a stream, the water kind of flows around it. But other times, those two systems couple (and) you dump mass, energy and momentum into the Earth system."

That coupling drives spectacular auroral displays, "but it also drives some of the negative things that we want to... understand and mitigate, like unplanned electrical currents in our electrical grids that can potentially cause accelerated aging in electrical pipelines, disruption of GPS, things like that."

"So what we're looking at trying to understand is how the coupling between those systems changes in space and in time," Miles said.

The goals of the other satellites launched Wednesday range from basic science to technology development. The Polylingual Experimental Terminal, or PExT, will test equipment capable of sending and receiving data from multiple government and commercial satellites across multiple communications protocols.

The goal is to streamline communications to and from a wide variety of satellites and space probes to improve efficiency and lower costs.

Another satellite, known as Athena-EPIC, will continue ongoing measurements of Earth's radiation budget, the balance between solar energy coming into Earth's environment compared to the energy radiated back out into space.

Using spare parts from earlier missions, Athena-EPIC will test innovative LEGO-like satellite components intended to lower costs while reducing the size of satellites.

The Relativistic Atmospheric Loss, or REAL, satellite, another small cubesat, will study how electrons in the Van Allen radiation belts get knocked out of place to pose threats to satellites and other systems. Robyn Millan of Dartmouth University is the principal investigator.

"The radiation belts are a region surrounding the Earth that are filled with high-energy charged particles that are traveling at near the speed of light," she said. "These are sometimes called killer electrons because these particles are a hazard for our satellites in space. They also rain down on our atmosphere where they can contribute to ozone destruction."

The REAL cubesat weighs less than 10 pounds and measures just a foot long. Despite its small size, "it carries a powerful particle sensor that will for the first time make very rapid measurements of these electrons as they enter our atmosphere, and this is really critical for understanding what's scattering them."

What makes REAL unique, she said, was the sensor's small size, allowing it to be carried by a cubesat, which "could enable future missions, especially those requiring constellations of satellites."