The Thermal Protection System — also known as the heat shield — for NASA’s Parker Solar Probe arrived in Titusville, Florida, on April 18, 2018, bringing it one step closer to reuniting with the spacecraft that will be the first to “touch” the Sun.
The Parker Solar Probe spacecraft arrived at Astrotech Space Operations two weeks prior, on April 3, to complete final testing. Though the spacecraft was flown by the Air Force’s 436th Airlift Wing, the Thermal Protection System, or TPS, traveled on a flatbed truck, securely encased in a metal shipping container during its road trip to the Sunshine State. After setting off on a rainy Monday morning from Maryland, it was greeted with Florida’s balmy heat on Wednesday afternoon at Astrotech, where it will eventually be reattached to the spacecraft before launch in late July.
The innovative TPS will be the one barrier shielding the spacecraft and its instruments from the intense heat of the Sun. Made of carbon-carbon composite and stretching approximately eight feet wide, the TPS will withstand temperatures of up to 2,500 degrees Fahrenheit while keeping the spacecraft and instruments at a comparatively comfortable 85 degrees Fahrenheit. The heat shield has a plasma-sprayed white surface that will reflect the intense heat energy of the Sun’s corona away from the spacecraft.
The second stage of a United Launch Alliance Delta IV Heavy is mated to the common booster core inside the Horizontal Integration Facility near Space Launch Complex 37 at Cape Canaveral Air Force Station in Florida.
The Delta IV Heavy will launch NASA’s upcoming Parker Solar Probe mission in July 2018. The mission will perform the closest-ever observations of a star when it travels through the Sun’s atmosphere, called the corona. The probe will rely on measurements and imaging to revolutionize our understanding of the corona and the Sun-Earth connection.
Parker Solar Probe has completed its space environment testing at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and was lifted out of the thermal vacuum chamber on March 24, 2018, after just over two months inside.
Since January, Parker Solar Probe underwent a series of tests inside NASA Goddard’s large thermal vacuum chamber – officially called the Space Environment Simulator – that mimicked the conditions the spacecraft will face in space throughout its seven-year mission. After initially testing the spacecraft’s functions under hot and cold extremes, engineers have spent the past month slowly cycling the temperatures in the thermal vacuum chamber back and forth between hot and cold, making sure Parker Solar Probe’s systems and components operate properly. This thermal cycling is similar to the conditions the spacecraft will experience as it completes 24 close approaches to the Sun over its seven-year mission.
“Successfully completing this final round of space environment testing is critical, and the team has created an exceptional spacecraft,” said Andy Driesman, Parker Solar Probe program manager from the Johns Hopkins Applied Physics Lab in Laurel, Maryland, which designed, built, and will manage the mission for NASA. “We now know the spacecraft and systems are able to operate in space, and that Parker Solar Probe is ready to embark on this historic mission.”
After undergoing final preparations, the spacecraft will leave NASA Goddard and travel to Florida this spring. Once in Florida, Parker Solar Probe will go through its final integration and testing at Astrotech Space Operations in Titusville before launching from NASA’s Kennedy Space Center in Florida this summer. Parker Solar Probe’s launch window opens on July 31, 2018.
On Saturday, Jan. 27, NASA’s Parker Solar Probe began space environment testing, starting with the air being pumped out of the 40-foot-tall thermal vacuum chamber at NASA’s Goddard Space Flight Center in Greenbelt, Maryland where the spacecraft is currently housed. The chamber – officially called the Space Environment Simulator – creates a nearly identical replication of the conditions the spacecraft will face during its mission to the Sun.
After the air was slowly removed from the chamber over the course of five hours, cooling tubes behind the chamber walls were chilled to -320 degrees Fahrenheit (-196 Celsius).
Engineers will cycle the chamber’s temperatures from hot to cold to ensure Parker Solar Probe will be prepared for operations around the Sun. During this cycling, the spacecraft’s systems will undergo testing that mimics critical events that occur during its planned seven-year mission in space. The tests are designed to make sure all the systems and components of Parker Solar Probe are operating as designed.
This space environment testing will continue for about seven weeks. Parker Solar Probe will emerge from the vacuum chamber in mid-March for final tests before setting off for Florida, where it will launch from NASA’s Kennedy Space Center on July 31, 2018.
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.
When NASA’s Parker Solar Probe lifts off on top of a Delta IV Heavy launch vehicle in summer 2018, it will undergo both intense vibration from the physical forces of the rocket engines, as well as acoustic effects from the sound of the engines and the rocket going through the atmosphere.
Verifying the spacecraft and its systems are ready for the rigors of launch is one of the most important parts of testing. On Nov. 3, Parker Solar Probe passed vibration testing at the Johns Hopkins Applied Physics Laboratory, or APL, in Laurel, Maryland, where it was designed and built. On Nov. 14, the spacecraft successfully completed acoustic testing at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and is now being prepared for further environmental tests.
Goddard’s Acoustic Test Chamber is a 42-foot-tall chamber that uses 6-foot-tall speakers –which can create sound levels of up to 150 decibels – to simulate the extreme noise levels of a rocket launch. While vibration testing focuses on how much the spacecraft will shake during launch, acoustic testing subjects the probe to intense sound forces, like those generated by the Delta IV Heavy. Each type of force affects the spacecraft differently, so both tests are necessary.
“We’re launching on a very large and powerful vehicle, so we need to make sure that the spacecraft, its systems, and its instruments are going survive the launch environment,” said Shelly Conkey, a Parker Solar Probe structural analyst at APL, who led the acoustic test. “We use our data models to predict the forces that will be impacting Parker Solar Probe, and by comprehensive monitoring of the spacecraft during testing, we can ensure that we’re ready to move on to thermal vacuum testing.”
Parker Solar Probe spacecraft will explore the Sun’s outer atmosphere and make critical observations that will answer decades-old questions about the physics of stars. The resulting data will also help improve how we forecast major eruptions on the Sun and subsequent space weather events that can impact life on Earth, as well as satellites and astronauts in space. The mission is named for Eugene N. Parker, whose profound insights into solar physics and processes have helped shape the field of heliophysics.