Usually the launch of a spacecraft marks the beginning of its journey, but for NASA’s Deep Space Climate Observatory (DSCOVR), this weekend’s planned liftoff may feel more like a conclusion. Since the satellite was literally dreamt up by then–Vice President Al Gore one night in 1998, it has been constructed, canceled, shelved, politicized, demonized, revived, renamed, and repurposed. Now, after a 17-year odyssey, the spacecraft formerly known as Triana, and widely referred to as Goresat, is scheduled to leave Earth at 6:05 p.m. on 10 February from Cape Canaveral Air Force Station in Florida. (The launch, originally scheduled for 8 February, has bee delayed several times for technical and other reasons.)
If all goes well, DSCOVR will end up in an orbit that is four times farther away from Earth than the moon, in a unique position that will keep the spacecraft situated between Earth and the sun at all times.
DSCOVR has two main goals. The National Oceanic and Atmospheric Administration (NOAA) will operate the craft’s space weather monitoring instruments, providing more accurate data about solar storms. NASA scientists, meanwhile, will gaze Earthward, using DSCOVR to monitor the planet’s radiation balance—a measurement that could give insight into climate change. The spacecraft is designed to orbit at what’s called the L1 Lagrange point—a position at which the satellite and Earth both orbit the sun at the same pace, keeping the spacecraft constantly sandwiched between the two bodies.
DSCOVR might never have gotten off the ground if NOAA hadn’t needed a new space weather satellite. The agency is tasked with monitoring the sun for coronal mass ejections and other solar events that can eject high-energy particles toward Earth and interfere with satellites or disrupt the power grid, leading to blackouts. Now, NASA’s Advanced Composition Explorer fills this role, but the veteran satellite is well past its planned life span and could stop communicating at any moment.
Originally, officials considered building a new satellite to do the job. But NOAA realized it would be cheaper to refurbish Gore’s Triana project, which had faced intense scrutiny in Congress and ultimately was shelved by NASA shortly after George W. Bush won the White House in 2000. The craft was sitting in storage until 2012, when NOAA committed $29.8 million to bring it back to life.
DSCOVR retains some of Triana’s Earth-observing instruments. One is a National Institute of Standards and Technology Advanced Radiometer (NISTAR), an apparatus that can measure the amount of radiation reflected from Earth’s surface back toward the sun. “In theory, if you know how much energy is coming in from the sun, and how much is reflected or radiated away, the difference is how much is heating or cooling the planet,” says Adam Szabo, a heliophysicist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
It’s a complex task, however, and researchers are hoping NISTAR will make it easier. One big problem is that Earth is not a circle, but rather a sphere, meaning radiation reflects off the surface in all directions, not just back at DSCOVR. Other satellites have been doing their best to measure the amount of solar radiation reflected from the planet piecewise, but calculating the full radiation budget has relied on mathematical models that stitch the close-ups together. In contrast, DSCOVR’s distant vantage point will allow it to see the big picture. “We’ll see the full sunny disk of Earth all at once. You don’t have to stitch the image together,” Szabo says.
DISCOVR’s space weather instruments are not intended to provide early warnings of incoming solar storms. Rather, they will document the storms as they pass by, providing researchers with detailed information about the storm’s intensity and properties in the 15 minutes to an hour before it reaches Earth. “The most important factor in the storms’ strength is the magnetic field and its direction; there’s no way to observe that remotely,” says NOAA physicist Doug Biesecker. The added data might even allow scientists to predict what region of Earth will be at the highest risk of damage.
Despite DSCOVR’s long, tortured history, some of its original personnel are still working on the project. In the late 1990s, physicist Francisco Valero led a team at the Scripps Institution of Oceanography in San Diego, California, that drafted the winning design for Triana’s instrumentation. He always hoped the shelved satellite would get a second chance. With a launch in sight, “from a personal point of view, I’m delighted,” says Valero, now an adviser to the mission. “With time, the best come to the top.”
Still, he cautions, DSCOVR has more than a million kilometers to travel and there’s a chance its story could end on the launch pad. “You know,” he says, “there’s always the terrible thought that the whole thing could go up in smoke in two-tenths of a second.” But he’s hoping for the best.
*Update, 9 February, 12 p.m.: This article, orginally published 6 February, has been upated with DSCOVR's new launch schedule.