Nicola Fox - Parker Solar Probe Project Scientist, Johns Hopkins Applied Physics Laboratory
Parker Solar Probe really is a historic mission, it was first dreamed of in 1958 and it has remained the highest priority mission throughout that period. The reason it hasn’t flown is just because it has taken a while for technology to catch up with the dreams that we had for this amazing mission.
The coolest thing about my job is just the sheer feeling that this is a 60-year journey that people have gone on to make Parker Solar Probe a reality and to be there at the finish line as we’re on the pad and ready to launch—that is definitely the coolest thing about my job.
Betsy Congdon - Lead Thermal Protection Engineer, Johns Hopkins Applied Physics Laboratory
After working on this for 10 years, it is really a pleasure to see it actually coming to fruition. To be one small part of this huge engineering team that is making science dreams come true is just amazing. I can’t wait to re-write textbooks and change the way we look at the Sun forever. I’m a whole ball of excited, and I honestly don’t know exactly how I’m going to feel at launch but I’m really excited to pass this off to the mission operations team and see all the science data that comes down and just get to enjoy all that Solar Probe brings us.
There are many enabling technologies, the solar arrays are really important, the autonomy is very important, one of the ones that is obviously also critical is the heat shield, and developing the technology to actually protect the probe at the Sun.
A sandwich panel is a lot like a honeycomb panel you find in a traditional spacecraft or on airplanes. You have the outer face sheets, and then you have a core. In this case the two outer face sheets are carbon-carbon composite, which is a lot like the graphite epoxy you might find in your golf clubs, it’s just been super-heated, and then the inside is a carbon foam. So the Parker Solar Probe heat shield has a white coating that’s on the Sun-facing surface of this giant frisbee that’s protecting the rest of the spacecraft. And that white coating was specially designed here at the lab, in collaboration with REDD and the space department as well as the Whiting school at Johns Hopkins proper, to actually work at the Sun, specifically designed for Solar Probe. And the concept is basically you’d rather be in a white car on a hot day, than a black car on a hot day—it just knocks down the heat that much more. So it’s helping us stay cool at the Sun.
The titanium truss was also specially designed for solar probe. It’s a really neat piece. It’s a welded titanium truss that’s about 4 feet tall, but it only weighs about 50 pounds. And the key there is we’re trying to minimize the conduction between the heat shield and the spacecraft, so you want to have as little stuff there as possible.
But then also the first closest approach will be a very interesting time. We’ll obviously be working towards closest approach a long time and getting science back from the beginning, but the heat shield has to do its hardest work 7 years into the mission, which has always been an interesting construct of the mission.
When we’re at closest approach, the front surface of the heat shield will be at about 2,500 degrees Fahrenheit. The back surface of the heat shield will be about 600 degrees Fahrenheit. But the spacecraft bus is basically sitting at 85 degrees Fahrenheit. So the shield is actually really keeping everything very cool, most of the stuff is on the bus.
The mission that is in its current form is actually a solar powered mission, whereas some of the earlier concepts were nuclear powered. So they just had different mission designs, there were different constraints on the mission, and so once this current form iteration with a flat heat shield, or 8-foot frisbee as we like to say, because it’s basically a giant sandwich panel protecting the spacecraft as an umbrella, really developed as a part of this solar-powered mission that is its most recent rendition. And so, reaching out with expertise all around the lab, that whole team really brought this heat shield to fruition.
Yanping Guo - Design and Navigation Manager, Johns Hopkins Applied Physics Laboratory
Of all the space missions I’ve worked on, Parker Solar Probe is the most challenging and complex mission to design and to fly. The launch energy required to reach the Sun is 55 times that required to get to Mars, and two times to Pluto.
Annette Dolbow - Integration and Test Lead Engineer, Johns Hopkins Applied Physics Laboratory
So the tensest moment for me after launch is when we’re sitting in the control room and we’re waiting for that green telemetry to show that the spacecraft is turned on and we can actually talk to it.