What can fly at 430,000 miles per hour and has a shield with superpowers?
The answer to the above question is the Parker Solar Probe. And the probe is about to to complete its first perihelion, or fly-by of the sun.
Scientists and engineers from NASA and Johns Hopkins Applied Physics Lab (APL) have designed the spacecraft to fly seven times closer to the sun than ever before attempted. Not only does the probe have to travel at amazing speeds with terrific accuracy, but it also must be protected from the immense heat that comes from flying into the corona of the sun.
With this fly-by, the probe passes within about 15 million miles of the Sun’s surface at a top speed of 213,000 miles per hour, setting records for both closest distance to the Sun and top speed of a spacecraft relative to the Sun. It’s expected to reach its top speed, 430,000 miles per hour in 2025 during its 24th and final perihelion.
The mission’s scientific goal
NASA and APL developed solar probe to fly through the sun’s atmosphere, as close as 3.8 million miles from the surface. According to NASA, “Coming closer to the sun than any previous spacecraft, Parker Solar Probe will employ a combination of in situ measurements and imaging to achieve the mission’s primary scientific goal: to understand how the sun’s corona is heated and how the solar wind is accelerated. Parker Solar Probe will revolutionize our knowledge of the origin and evolution of the solar wind.”
Design challenge: Create a shield with superpowers
The probe’s heat shield is a critical component of the mission because it will have to deal with the sun’s extreme heat without melting. Adding to that challenge is the fact that the shield can’t tilt more than one degree in any direction without risking damage to the rest of the craft. “Betsy Congdon, APL’s lead engineer working on the heat shield, told Space.com that the probe’s heat shield has its own superpower: The hotter it gets, the better it works. This is great news for the probe, since it will face grueling temperatures of 2,500 degrees F (1,370 degrees C) — more than 400 times as intense as what Earth-orbiting spacecraft endure — while the sensitive instruments underneath will enjoy a balmy 85 degrees F (29 degrees C),” stated Space.com.
The side of the shield that faces the sun is covered in a coat of white ceramic paint to help deflect as much of the sun’s light, and therefore heat, as possible. The shield is only 8 feet in diameter and weighs just 160 lbs. Its job is to protect the instruments below it.
According to NASA, “Parker Solar Probe employs a host of autonomous systems to keep the spacecraft safe without guidance from Earth — including automatic retraction of the solar panels to regulate their temperature, attitude control using solar limb sensors that ensures all of the instruments remain in the heat shield’s shadow, and a sophisticated guidance and control system that keeps the spacecraft pointed correctly.”
To keep the craft pointed correctly, the Parker has limb sensors that are meant to stay in the shade of the shield. If the sensors detect light, they signal the craft to autonomously adjust its orientation to the Sun, ensuring the instruments remain protected from the heat.
NASA utilized Simulink to design the shield orientation and “sophisticated guidance and control system.” In a report that discusses the science and technology used in the probe design, NASA states, “The G&C attitude estimation and control algorithms are developed by using MATLAB Simulink models. [Simulink Coder] is used to generate C code from the Simulink models, which is then compiled into the G&C flight software.”
To see more comments from the Parker Solar Probe team, check out this AMA on Reddit.
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