Solar Probe On The Way To The Sun

2023 Author: Hannah Pearcy | [email protected]. Last modified: 2023-05-24 11:12

Solar Orbiter, a flagship project of ESA and NASA, is scheduled to launch on February 8. In the course of its multi-year mission, the spacecraft is to observe the sun and carry out measurements that have never been undertaken before. The probe will also provide the first images of the polar regions of the sun. The heat shields have to withstand enormous loads from the sun.

The Solar Orbiter wants to answer the following important questions:

Solar wind: What drives the solar wind and the acceleration of the solar wind particles?

Polar regions: What happens in the polar regions when the solar magnetic field changes polarity?

Magnetic field: How is the magnetic field generated inside the sun and how does it spread through the sun's atmosphere and out into the room?

Space weather: How do sudden events such as flares and coronal mass ejections affect the solar system and our earth?

The Solar Orbiter is scheduled to launch on February 8, 2020 with an Atlas V 411 rocket from Cape Canaveral in Florida. To approach the sun, the Solar Orbiter uses the gravity of Venus and the Earth. Throughout the mission, the probe will keep coming back near Venus and tilting or slightly changing its own orbit using the planet's gravity to take different perspectives of the sun.

Picture gallery

Picture gallery with 9 pictures

Hostile regions: 42 million kilometers from the sun

The Solar Orbiter has to operate in one of the most hostile regions of the solar system for years. It will approach the sun approximately 42 million kilometers, which is just over a quarter of the distance between the sun and the earth. So close to the sun, the probe will be 13 times more intensely exposed to sunlight than what we feel on earth. The orbiter must also endure strong bursts of particle radiation from explosions in the solar atmosphere. The heat shield of the probe is the key that makes the mission possible, since the probe has to withstand temperatures of 500 ° C. Small sliding doors with heat-resistant windows allow sunlight to penetrate the scientific instruments that are located directly behind the heat shield.

The ten instruments on board:

• Energetic particle detector: Measures energetic particles that flow past the spaceship. The data will help scientists to study the sources, acceleration mechanisms and transport processes of these particles.
• Magnetometer: Measures the magnetic field around the spacecraft. It will help determine how the sun's magnetic field is connected to the rest of the solar system and how it changes over time.
• Radio and plasma waves: Measures the variation of the magnetic and electrical fields with a series of sensors and antennas. This will help determine the properties of the electromagnetic waves and fields in the solar wind.
• Solar wind plasma analyzer: A number of sensors measure the volume properties of the solar wind (e.g. density, speed and temperature). It will also measure the composition of the solar wind.
• Extreme ultraviolet imager: Takes pictures of the solar chromosphere, the transition region and the corona. This enables the scientists to investigate the mysterious warming processes in these regions.
• Coronagraph: Takes pictures of the corona in the visible and ultraviolet wavelength range at the same time. This will show the structure and dynamics of the sun's atmosphere in unprecedented detail.
• Polarimetric and helioseismic image sensor: Provides high-resolution measurements of the magnetic field in the entire photosphere and maps its brightness at the visible wavelengths. Creates speed maps of photosphere motion.
• Heliosphere Imager: Takes pictures of the solar wind by capturing the light scattered by the electron particles in the wind. This will enable the identification of transient disturbances in the solar wind.
• Spectral imaging of the coronal environment: Reveals the properties of the solar transition region and the corona by measuring the extreme ultraviolet wavelengths emitted by the plasma.
• X-ray spectrometer / telescope: Detects the X-rays emitted by the sun. This could come from hot plasma, which is often associated with explosive magnetic activity such as solar flares.

In detail: The X-ray telescope STIX

STIX is designed to examine solar eruptions more closely and perhaps make it possible to predict large eruptions. It was developed at the University of Applied Sciences of the University of Applied Sciences Northwestern Switzerland (FHNW) in collaboration with several Swiss industrial partners such as Almatech. Swiss drives from Maxon are also used in the X-ray telescope. Two specially modified DC motors with a diameter of 13 millimeters move an aluminum damping network, which is pushed in front of the 30 STIX detectors as required. The micro drives are placed in parallel, can be operated together or individually, which ensures smooth operation over the entire planned mission. The design is based on micromotors that will soon be used in ESA's Exo Mars rover. The low weight, energy efficiency and vibration resistance played an important role in the selection of the drives.