July 7th, 2018
For the first time since the Fall of 2017, NASA’s Parker Solar Probe is a fully integrated spacecraft and is inching closer to its launch date. Engineers from the Johns Hopkins Applied Physics Lab (APL) recently attached the probe’s 160-pound (72.6-kilogram) thermal protection system, or heat shield, to the body of the spacecraft in preparation for its launch, scheduled for no earlier than Aug. 4, 2018.
The Parker Solar Probe needs every bit of cover the heat shield can provide in order to protect its scientific instruments and spacecraft components from the searing heat of the Sun as it flies through its atmosphere, or corona.
Made of twin carbon-carbon composite panels—between which is sandwiched a 4.5-inch (114.3-millimeter) core of lightweight carbon foam—the shield should keep the body of the spacecraft at a comparatively cool 85 degrees Fahrenheit (29.4 degrees Celsius), according to NASA. For comparison, the Sun-facing side of the shield is expected to climb to a blistering 2,500 degrees Fahrenheit (1,371.1 degrees Celsius).
Though there is no shortage of materials on Earth designed to withstand the temperatures the Parker Solar Probe is expected to encounter, the solution needed to be incredibly light. Indeed, even though the United Launch Alliance Delta IV Heavy is more than capable of launching the 1,510-pound (685-kilogram) spacecraft if it were simply destined for an Earthly orbit, the probe needed to be as svelte as possible in order to reach its heliocentric, or Sun-centered, orbit.
In fact, although the Parker Solar Probe only tips the scales at slightly more than 2.3 percent of the rocket’s capacity to low-Earth orbit (LEO), an additional upper stage needed to be added to the vehicle’s configuration so the probe would be able to travel fast enough to reach its intended orbit, which is ultimately expected to take it within roughly four million miles (6.44 million kilometers) from the Sun. Once there, the spacecraft will be traveling faster than 430,000 mph (692,018 kph) at its closest point from the Sun.
At that speed, the Parker Solar Probe could travel from New York City to Tokyo in less than a minute. The mission’s orbit is designed to take the spacecraft seven times closer to the Sun than any previous spacecraft, and 10 times closer to the Sun than the planet Mercury.
In order to get to that final orbit, however, the probe needs to swing by the planet Venus seven times, each encounter gradually shrinking the spacecraft’s orbital period, which should ultimately be about 88 days. The first of these flybys is expected to occur in late September 2018 with the final expected in November of 2024.
Video courtesy of NASA Goddard
Curt Godwin has been a fan of space exploration for as long as he can remember, keeping his eyes to the skies from an early age. Initially majoring in Nuclear Engineering, Curt later decided that computers would be a more interesting – and safer – career field. He’s worked in education technology for more than 20 years, and has been published in industry and peer journals, and is a respected authority on wireless network engineering. Throughout this period of his life, he maintained his love for all things space and has written about his experiences at a variety of NASA events, both on his personal blog and as a freelance media representative.