Our solar system is made up of a star – our Sun, 8 planets and over 145 moons. The Sun, is of course, the only star in our solar system. And it has been burning for 4.6 billion years now. Curious minds have always looked up to the sun and imagined what has kept it bright and burning for so long. The surface of the Sun is about 10,000 degrees Fahrenheit hot, with core temperatures reaching more than 27 million degrees F driven by nuclear reactions. The high temperatures have obviously stopped mankind from approaching the surface of the sun, or coming anywhere close.
In other words, despite our curiosity and advancements in space research and technology, the Sun had been beyond our reach for the longest time.
Emphasis on the ‘had’, however, because ‘touching’ the sun might have just become possible with the Parker Solar Probe from NASA.
The Parker solar probe is an exemplary evidence of scientific innovation in the field of space science, and has set out to achieve what was once considered impossible – studying the sun for research and quenching our curiosity. NASA’s solar mission carrier, the solar probe is an accomplishment of one of the founding goals of NASA.
Merely ,onths after it was founded in October 1958, NASA heads had put forward a few central goals for the organization. One of them was to enter the inner orbit of Mercury and study the vicinity of the Sun from there.
With the Parker Solar Pobe, Touching the Sun is Now a Reality
The Parker Solar Probe is travelling to the Sun’s atmosphere, closer to the surface than any spacecraft before it. It’ll brutal heat and radiation to provide humanity with the closest-ever observations of a star. The probe was launched in Aug 2018 from the Cape Canaveral Air Force Station in Florida.
But what exactly is behind the solar probe being considered as an engineering marvel? Let’s take a look at the engineering behind Parker solar probe to understand its development and design more carefully.
Trajectory For the Solar Probe
Let’s begin with the understanding of how the Parker solar probe entered the vicinity of the Sun. Everyone knows that Earth, along with every other planet in the solar system, is orbiting the Sun at a very high speed. But as the spacecraft will go closer to the Sun, it needs to orbit at a speed lower than the Earth, or else it cannot get into closer orbits around the Sun. So the first task for the engineers was to find a way to first get the solar probe out of Earth’s gravitational influence by accelerating it at a high speed, but then decelerate it at the right time to be ready for entering a close proximity orbit around the Sun.
For getting the probe out of Earth’s orbit, its engineers used a third stage booster apart from primary boosters and second stage that ran out of the fuel. This helped the probe get out of the Earth’s pull and the trajectory for the Parker solar probe was designed very carefully.
After getting out of Earth’s vicinity, the space probe then swung by 24 orbits out of which it traveled around Venus seven times. The plan was to use Venus’ gravity during seven flybys over nearly seven years to gradually bring its orbit closer to the Sun. The spacecraft is set to fly through the Sun’s atmosphere as close as 3.8 million miles to our star’s surface, well within the orbit of Mercury and more than seven times closer than any spacecraft has ever achieved.
The Parker Solar Probe employs a combination of in situ measurements and imaging while flying towards the outermost part of the Sun’s atmosphere, called the corona, to revolutionize our understanding of it. This would help us expand our knowledge of the origin and evolution of the solar wind while making critical contributions to our ability to forecast changes in Earth’s space environment that affect life and technology on Earth.
The Parker solar probe from NASA had its deceleration planned out through this method. The shedding velocity of the solar probe continued decreasing and by the time it crossed Venus and Mercury, it was within a 4 million miles radius of the Sun.
That is seven times closer compared to any other solar space probes before it.
Even with decreased shedding speed, the relative speed of the solar probe with respect to the Sun, i.e. 430,000 mph, makes the space probe the fastest human made object in existence.
Protection From the Sun
The next obvious question that springs to our minds is how well the solar probe is protected against the solar heat and radiation.
The solution was to shield the space probe from solar radiations and the solar winds using a thermal protection system installed on the Parker solar probe According to the calculations, about 3 million watts of energy was to fall upon the solar probe while it was close to the Sun. NASA built a 4.5-inch-thick (11.43 cm) carbon-composite shield, which can withstand temperatures reaching nearly 2,500 degrees Fahrenheit. Thanks to advancements in composite material engineering, NASA could come up with a light-weight material that added only minimal weight to the space probe, enabling superior speed control. This would not have been possible if the mission was launched in the 1960s or even the 80s when high temperature resistivity metals would be bulky.
The Parker solar probe currently uses a carbon-carbon layered structure and can survive the Sun’s harsh conditions because cutting-edge thermal engineering advances protect the spacecraft during its journey.
NASA made the carbon fiber sheets and then filled the resin of chopped up carbon fibers in between the sheets. Now they hardened the resin before it got burnt off after 3000 degrees made the whole structure look like it is one single material. This solved the problem of resin melting off and destroying the shield at high temperatures.
Powering Up the Space Probe
The Parker Solar Probe is an engineering marvel that awed the world when it was launched using the Delta IV-Heavy with Upper Stage. The spacecraft is powered by two solar panels, each with two-axis tracking, producing 2.7 kW on Earth and 1.2 kW at 1.3 AU during the science phase.
The spacecraft has the most efficient powering system and even the most efficient cooling system built into it. The computers and other machinery on the probe are powered by solar cells. But at such close proximity to the Sun, for every watt of power generated, the solar panels experienced thirteen watts of heat. This needs to be monitored as large amounts of heat can also damage the system.
To cool the whole system, NASA used water after testing fifty materials as coolant for the space probe. It also built tiny tubes into the titanium platen system for the radiator. Water would collect the heat from the solar panel, take it through the titanium platen and then radiate it via the radiator window into outer space.
Even with such an efficient cooling system and the powering mechanism, its solar panels were designed to fold and get behind the heat shield. This was because even such an efficient mechanism could not bear such high heat at the closest proximity of the Sun. Only one part of the solar panels at a sharp angle was placed to collect energy from the Sun and power up the systems.
Protection Against the Meteorites and Space Debris
Now that the engineers tackled two of the problems, the last one was protecting the spacecraft against meteorites and the space debris. At speeds like 200-300 miles per hour, even dust particles can cause significant damage to the spacecraft. The Parker solar probe was therefore given a Kevlar armor against the micrometeorites and the debris. There was not much to put into this armor as it was also made of the carbon fiber material and acted as a blanket against the hypothesized dust material in the vicinity of the Sun. It protected the cooling lines of the space probe from any punctures and kept it safe from the space debris as well.
The Fastest Man Made Object in the Universe
As of March 17th, 2023, NASA’s Parker Solar Probe completed its 15th close approach to the Sun, coming within 5.3 million miles of the scorching solar surface. The shape of Parker solar probe’s latest orbit also placed it in direct view of Earth and several other Sun-observing spacecraft during its close encounter. This provides unique scientific opportunities for collaborative observations from the ground and space.
Six decades after NASA thought of getting close to the Sun, the Parker Solar Probe is already a successful accomplishment of this dream. The Parker Solar Probe is truly a work of art in terms of design and engineering. No wonder it took such a long time to fulfill this singular dream. NASA is still collecting data from the solar probe as it is designed to be sending data until 2025 from its various orbits around the Sun. It can be concluded that the Parker solar probe mission has proved to be a significant success for humanity and paved the path for further exploration missions. Here’s a link to an informative video.