NASA’s Parker Solar Probe gets its power from the Sun, so the solar arrays that collect energy from our star need to be in perfect working order. This month, members of the mission team tested the arrays at Astrotech Space Operations in Titusville, Florida, to ensure the system performs as designed and provides power to the spacecraft during its historic mission to the Sun.
Parker Solar Probe is powered by two solar arrays, totaling just under 17 square feet (1.55 square meters) in area. They are mounted to motorized arms that will retract almost all of their surface behind the Thermal Protection System – the heat shield – when the spacecraft is close to the Sun.
You don’t get to swim in the Sun’s atmosphere unless you can prove you belong there. And Parker Solar Probe’s Faraday cup, a key sensor on the spacecraft, earned its stripes on April 19 by enduring testing in a homemade contraption designed to simulate the Sun.
The cup will scoop up and examine the solar wind as the probe passes closer to the Sun than any previous human-made object. In order to confirm the cup will survive the extreme heat and light of the Sun’s corona, researchers previously tortured a model of the Faraday cup at temperatures exceeding 3,000 degrees Fahrenheit, courtesy of the Oak Ridge National Laboratory’s Plasma Arc Lamp. The cup, built from refractory metals and sapphire crystal insulators, exceeded expectations.
But the final test took place on April 19, in a homemade contraption Kasper and his research team call the Solar Environment Simulator. While being blasted with roughly 10 kilowatts of light on its surface—enough to heat a sheet of metal to 1,800 degrees Fahrenheit in seconds—the Faraday cup model ran through its paces, successfully scanning a simulated stream of solar wind.
Justin Kasper, University of Michigan associate professor of climate and space sciences and engineering, is principal investigator for Parker Solar Probe’s Solar Wind Electrons Alphas and Protons (SWEAP) investigation.
NASA’s Parker Solar Probe will carry 1,137,202 submitted and confirmed names on its journey to the Sun. Submissions opened on March 6, 2018, and closed on April 27 at 11:59 p.m. EDT. A chip containing the names will be installed onto the spacecraft before launch.
NASA’s Parker Solar Probe is rotated down to a horizontal position during pre-launch processing and testing on April 10, 2018, at Astrotech Space Operations in Titusville, Florida, just outside Kennedy Space Center. Once horizontal, the integration and testing team will measure the alignment of the heat shield mounting points with respect to the spacecraft structure. This is done to assure that the umbra (or shadow) cast by the heat shield – called the Thermal Protection System – protects the spacecraft and instruments.
On the morning of Tuesday, April 17, 2018, crews from United Launch Alliance raised the 170-foot tall Delta IV Heavy launch vehicle – the largest and most powerful rocket currently used by NASA – at Launch Complex 37 at Cape Canaveral Air Force Station in Florida. This Delta IV Heavy will carry Parker Solar Probe, humanity’s first mission to the Sun’s corona, on its journey to explore the Sun’s atmosphere and the solar wind. Launch is scheduled for approximately 4 a.m. EDT on July 31, 2018.
The launch vehicle consists of three Common Booster Cores, with a second stage on the center core; the encapsulated spacecraft, is scheduled to arrive in early July for integration onto the rocket. The spacecraft is now at Astrotech Space Operations in nearby Titusville undergoing final integration and testing. Parker Solar Probe will be the fastest human-made object in the solar system, traveling at speeds of up to 430,000 miles per hour (700,000 kilometers per hour).
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.
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.