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An extreme mission

Artist’s impression of the Parker Solar Probe observing the Sun

A new probe

In summer 2018, NASA will be sending a probe to explore our very own star as closely as possible, getting nearer to the Sun than any before it. NASA has named the solar probe and spacecraft the Parker Solar Probe, in honour of astrophysicist Eugene Parker, who has revolutionised humanity’s knowledge of the Sun.

The project was first planned 60 years ago, but it was not realised because of insufficiently advanced technology. Fortunately, technology has evolved, and we can finally achieve the dreams of generations of astrophysicists.

The project aims to help scientists understand the Sun better than ever before. We want to know how it works, how it can generate so much energy and better understand its dangers when firing charged particles. Beyond understanding the mechanisms of the Sun, we may be able to develop our own technology further to prepare for the potentiality of extraterrestrial civilisation.

All life on Earth acquires energy from this single star, and just 8% of its fusion energy is enough for all living beings. Imagine what we could achieve in modern society by using this clean energy instead of coal, crude oil and gas, without worrying about energy shortage. If we can figure out how to safely use fusion, with only simple ingredients such as hydrogen atoms, human civilisation will advance in leaps and bounds. This mission may help with this.

However, that is also a huge challenge, with mysteries such as:

Solar winds: What causes solar winds to become stronger or weaker? As charged particles such as protons and electrons from solar winds are neither good for our human bodies nor modern electronic devices, how can we predict their intensity in advance and avoid damage?

Corona: As this is the atmosphere of the Sun which is furthest from the core, we expect it to be cool. However, the temperature rises to millions of degrees Celsius – much higher than the surface. What causes this?

Corona of the Sun

How close will the probe get to the Sun?

Parker will be 5.9 million kilometres away from the surface of Sun. That may sound very far away but, for comparison, this is just 4% of the distance between Earth and the Sun.

As you might expect, the heat energy and radiation received from the sun may be a challenge for the probe’s valuable instruments. Usually, astrophysicists worry about the probes getting too little solar energy to power flight. By contrast, we need to worry about Parker being on the receiving end of too much heat energy – and melting or exploding.

Of course, scientists from different areas such as engineering and materials have been working on this for a long time to protect the priceless instruments and ensure longevity. NASA has developed a 4.5in thick, 8ft diameter shield consisting of a carbon-carbon structure. Recently, the shield was shown in an official video, in which the heat shield was placed on the probe for an alignment test. Both spacecraft and shield will continue separate testing processes and then be re-integrated just before launch in summer 2018. The shield protects the spacecraft and its four main instruments from the intense heat and radiation of the Sun’s outer atmosphere throughout the 13 flybys and 24 rounds of orbit.

How will the probe get closer to the Sun?

The trajectory uses Venus flybys without any deep space manoeuvres, to reach a minimum perihelion of 8.5 solar radii (above the Sun’s surface) in 6.4 years

The probe will get closer to the Sun with each orbit. By using Venus and Mercury’s gravitational drag, Parker will get closer to Venus first, losing momentum, and then get closer to Mercury by doing the same thing. Finally, it will start to orbit around the Sun in 2024 – roughly six years’ time.

Although more than ten months remain before its real launch, and a few years before it sends back signals, we can keep tracking the progress of the probe. Hopefully, with the data received we may be able to study the conception of the Solar System, and extend our knowledge of the world’s origin by pushing these limits of astronomical research.