April 11, 2024 — You could have flown a flight simulator in a pc recreation or at a science museum. Touchdown with out crashing is all the time the toughest half. However that’s nothing in comparison with the problem that engineers are going through to develop a flight simulation of the very giant autos obligatory for people to discover the floor of Mars.
The Crimson Planet poses innumerable challenges to astronauts, not the least of which is getting there. That’s the place the Division of Vitality Workplace of Science’s consumer facility supercomputers are available. Researchers at DOE’s Oak Ridge Management Computing Facility (OLCF) are working with NASA engineers and scientists to simulate the method of slowing down an enormous spacecraft because it strikes in direction of Mars’ floor.
Touchdown spacecraft on Mars isn’t new to NASA. The company ran its first missions to the planet in 1976 with the Viking mission. Since then, NASA has efficiently carried out eight further Mars landings.
What makes this aim completely different is the truth that it’s far more troublesome to land the massive spacecraft required for human exploration than these for robotic missions. The robotic autos use parachutes to decelerate by way of Mars’ environment. However a spacecraft carrying people will probably be about 20 to 50 occasions heavier. A automobile this huge merely can’t use parachutes. As a substitute, NASA might want to depend on retro-propulsion. This expertise makes use of rockets that fireside forwards to decelerate the automobile because it approaches the floor.
Numerous challenges include utilizing retropropulsion. The high-energy rocket engine exhaust interacts with each the automobile and the Martian environment. These dynamics change how the staff must information and management the automobile. As well as, engineers can’t totally replicate how a flight on Mars would go on Earth. Whereas they’ll take a look at spacecraft in wind tunnels and use different instruments, these instruments aren’t an ideal substitute or direct analog for the Martian atmosphere.
To fill within the gaps, NASA turned to the OLCF supercomputers and their professional laptop scientists. In concept, packages operating on supercomputers might totally simulate the Martian atmosphere and most of the advanced physics related to utilizing retropropulsion.
The mission staff has relied on FUN3D, a long-standing suite of software program instruments that fashions how fluids – together with air – transfer. Engineers created the primary model of the code within the late Eighties and have regularly made main enhancements since then. Companies and firms in aeronautics and house expertise have used it to sort out main challenges.
The present Mars effort started in 2019 on Summit, OLCF’s quickest laptop on the time. The preliminary simulations assumed fastened circumstances. They simulated only one level alongside the automobile’s trajectory. These early variations allowed scientists to judge the impacts of flight speeds, engine settings, and extra. Additional developments enabled engineers to discover actual gasoline results. They might account for the liquid oxygen-methane rocket engines and the carbon dioxide-heavy Martian environment. Even these early simulations sometimes resulted in petabyte-sized datasets. It will take about 1,000 highly effective dwelling computer systems to retailer a single petabyte. However even these weren’t full simulations – that wasn’t potential but.
The subsequent step was to include an entire new piece of software program into the simulation – the Program to Optimize Simulated Trajectories (POST2). NASA developed POST2 to research flight mechanics for a broad vary of purposes. Whereas preliminary simulations relied on static circumstances, POST2 allowed scientists to dynamically “fly” the automobile within the simulation. The staff engaged researchers from Georgia Tech’s Aerospace Techniques Design Laboratory. That they had beforehand developed distinctive methods to couple POST2 with high-fidelity aerodynamic simulations.
Incorporating POST2 additionally required engineers to vary the mission workflow. The software program’s use was restricted to NASA computing techniques for safety causes. As such, the staff wanted to make sure the NASA techniques might talk easily with Summit at OLCF. Resolving points with firewalls, community interruptions, and different packages required a full 12 months of planning for the cybersecurity and system administration groups at each amenities!
The most recent advance concerned shifting all the simulation over to the latest and strongest laptop at OLCF – Frontier. The primary exascale laptop on the earth, Frontier is massively extra highly effective than earlier supercomputers. With a collection of coordinated runs over a two-week interval, the staff ran its most elaborate flight simulation up to now. It was a 35-second closed-loop descent from 5 miles altitude to roughly 0.6 miles. The simulation slowed the automobile from 1,200 miles per hour to roughly 450 miles per hour. POST2 was in a position to autonomously management the automobile in a secure style utilizing its eight essential engines and 4 response management system modules.
With the immense energy offered by Frontier at OLCF, NASA engineers are shifting ahead to sort out new frontiers in house journey.
Supply: Shannon Brescher Shea, DOE Workplace of Science
