A new spacecraft is set to launch on a journey to the Sun. It’s goal: to snap the first pictures of the Sun’s north and south poles.
Dubbed Solar Orbiter, the spacecraft is a collaboration between the European Space Agency (ESA) and NASA. The 3,970-lb. (1,320 kg) spacecraft will launch atop United Launch Alliance (ULA) Atlas V rocket on Feb. 7, 2020, during a two-hour launch window that opens at 11:15 p.m. EST (0415 GMT Feb. 8).
It’s launching at night because the spacecraft is on a path to Venus where it will use the planet’s gravity to slingshot itself out of the ecliptic plane — the area of space where all planets orbit.
From that vantage point, Solar Orbiter’s on-board cameras will capture the first-ever view of the Sun’s poles.
“Up until Solar Orbiter, all solar imaging instruments have been within the ecliptic plane or very close to it,” Russell Howard, space scientist at the Naval Research Lab in Washington, D.C. and principal investigator for one of Solar Orbiter’s ten instruments said in a mission update. “Now, we’ll be able to look down on the Sun from above.”
“It will be terra incognita,” added Daniel Müller, ESA project scientist for the mission at the European Space Research and Technology Centre in the Netherlands. “This is really exploratory science.”
The spacecraft is taking a suite of specialized instruments with it on its journey to the sun. It will also work in tandem with another solar-observing spacecraft—NASA’s Parker Solar Probe.
Launched in 2018, Parker has now completed its first few close passes of the sun. The spacecraft is already making discoveries, showing that despite appearance, the sun is anything but quiet.
It plays a central role in shaping space around us. As a magnetically active star, the sun unleashes powerful bursts of light and a slew of charged particles (racing at near light-speed) across the solar system. This violent activity has been happening throughout the sun’s 5.5 billion-year lifespan and affects our planet daily.
The sun has a massive magnetic field, which stretches far beyond Pluto, and creates the boundary between our solar system and interstellar space. It also creates a path for charged particles to whiz across the solar system.
The barrage of energetic particles, known as the solar wind, can damage spacecraft, satellites, and is harmful to our astronauts. It can disrupt navigation signals, and during extreme flares, can even trigger power outages.
But we can prepare for these things by monitoring the sun’s activity and magnetic field. However, our view from Earth is limited and leaves us with incomplete data. Scientists are hoping that by observing the sun’s polar regions, Solar Orbiter will be able to fill in the gaps in our knowledge.
“The poles are particularly important for us to be able to model more accurately,” Holly Gilbert, NASA project scientist for the mission at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “For forecasting space weather events, we need a pretty accurate model of the global magnetic field of the Sun.”
Solar Orbiter will take seven years to reach a viewpoint 24 degrees above the Sun’s equator, increasing to 33 degrees if the mission is extended an additional three years. That will provide the best views ever of the poles.
Additionally, the poles may be able to shed some light on the driving force behind sun spots — dark spots on the sun’s surface that mark strong magnetic fields. In 1843, German astronomer, Samuel Heinrich Schwabe, discovered that the spots increase and decrease during the solar cycle in a repeating pattern.
There are an abundance of sunspots during solar maximum (when the sun is active and turbulent) and fewer during solar minimum (when the sun is calmer). But scientists don’t understand why the cycle lasts 11 years, or why some solar maximums are stronger than others.
They hope to find the answer by observing the changing magnetic fields at the poles.
There’s only been one other spacecraft to fly over the sun’s polar regions: another joint ESA/NASA venture called Ulysses. It made three passes around the sun before being decommissioned in 2009. However, unlike Solar Orbiter, Ulysses did not have an imager on board to take pictures of the poles.
That spacecraft also did not get nearly as close as Solar Orbiter will. That’s because it lacked the technology required to keep it cool. Scientists have been waiting more than 60 years for missions like Parker Solar Probe and Solar Orbiter to come online.
It’s takes a lot of technology development to be able to design and build a spacecraft that will survive a close encounter with the sun.
Solar Orbiter is outfitted with a custom-designed titanium heat shield, topped with a calcium phosphate coating that withstands temperatures over 900 degrees Fahrenheit (482 degrees Celsius). That’s thirteen times the amount of heat that spacecraft in Earth-orbit are subjected to.