On Wednesday, Jan. 17, NASA’s Parker Solar Probe was lowered into the 40-foot-tall thermal vacuum chamber at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. The spacecraft will remain in the chamber for about seven weeks, coming out in mid-March for final tests and packing before heading to Florida. Parker Solar Probe is scheduled to launch from NASA’s Kennedy Space Center on July 31, 2018, on a Delta IV Heavy launch vehicle.
The thermal vacuum chamber simulates the harsh conditions that Parker Solar Probe will experience on its journey through space, including near-vacuum conditions and severe hot and cold temperatures.
“This is the final major environmental test for the spacecraft, and we’re looking forward to this milestone,” said Annette Dolbow, Parker Solar Probe’s integration and test lead from the Johns Hopkins Applied Physics Lab. “The results we’ll get from subjecting the probe to the extreme temperatures and conditions in the chamber, while operating our systems, will let us know that we’re ready for the next phase of our mission – and for launch.”
During thermal balance testing, the spacecraft will be cooled to -292 degrees Fahrenheit. Engineers will then gradually raise the spacecraft’s temperature to test the thermal control of the probe at various set points and with various power configurations.
Next, thermal cycling testing will transition the spacecraft from cold to hot and back again several times, simulating the conditions it will experience many times during its mission to the Sun. The Parker Solar Probe team will also test operation of the spacecraft’s hardware at both hot and cold plateaus, as well as perform a mission simulation.
To protect NASA’s Parker Solar Probe from the intense heat of the Sun’s atmosphere, scientists and engineers developed a revolutionary Thermal Protection System. This heat shield, made of carbon-carbon composite material, will experience temperatures of almost 2,500 degrees Fahrenheit as the spacecraft hurtles through the solar atmosphere, while keeping the instruments on the spacecraft at approximately room temperature.
The heat shield recently moved from the Johns Hopkins Applied Physics Lab, or APL, in Laurel, Maryland, to NASA’s Goddard Space Flight Center in Greenbelt to undergo testing in NASA Goddard’s large Thermal Vacuum Chamber. The Thermal Vacuum Chamber will simulate the harsh conditions that the heat shield must endure during the mission: This includes the airless vacuum of space along with huge temperature fluctuations between hot and cold as the spacecraft swings past the Sun and back out into space. The Thermal Protection System’s ability to withstand extreme temperatures has already been proven through testing at other facilities, as the Thermal Vacuum Chamber at NASA Goddard cannot simulate the very high temperatures of the Sun.
By Geoff Brown Johns Hopkins University Applied Physics Lab
NASA’s Parker Solar Probe passed laser illumination testing the week of Nov. 27, 2017. During this test, each segment of the spacecraft’s solar panels was illuminated with lasers to check that they were still electrically connected after the vigorous vibration and acoustic testing completed earlier this fall.
NASA’s Parker Solar Probe is in the midst of intense environmental testing at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, in preparation for its journey to the Sun. Parker Solar Probe’s integration and testing team must check over the spacecraft and systems to make sure everything is still in optimal working condition after these rigorous tests – including a check of the solar arrays, which will provide electrical power to the spacecraft. Credit: NASA’s Goddard Space Flight Center/Joy Ng Download this video in HD formats from NASA Goddard’s Scientific Visualization Studio
Parker Solar Probe is in the midst of intense environmental testing at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, in preparation for its journey to the Sun. These tests have simulated the noise and shaking the spacecraft will experience during its launch from Cape Canaveral, Florida, scheduled for July 31, 2018.
Parker Solar Probe’s integration and testing team must check over the spacecraft and systems to make sure everything is still in optimal working condition after experiencing these rigorous conditions – including a check of the solar arrays, which will provide electrical power to the spacecraft.
“This illumination testing verifies that each ‘string’ of solar cells on the array remains electrically connected to the spacecraft after vibration and acoustic testing,” said solar array lead engineer Ed Gaddy of the Johns Hopkins Applied Physics Lab, or APL, in Laurel, Maryland. APL is building and will operate the spacecraft.
To make sure that the 44 strings — a series of connected solar cells — on each panel are still well-connected after environmental tests, each string was illuminated individually to ensure that they would still create electricity and transfer it to the spacecraft. Lasers are ideal for this kind of testing, because their narrow beam allows the team to illuminate just one string at a time. The strikingly colored lasers were selected because they were readily available and because the solar cells operate efficiently at that color. But by themselves, these visible lasers are insufficient to power the solar cells, so the team also used infrared lasers for this test. Infrared light is not visible to our eyes and wasn’t captured in these images.