Athena will transport NASA's PRIME-1 (Polar Resources Ice Mining Experiment-1) which includes two instruments: a drill and spectrometer. The Regolith and Ice Drill for Exploring New Terrain (TRIDENT) is designed to drill up to three feet of lunar surface to extract soil, while the mass spectrometer (MSOLO) will measure the amount of ice in the soil samples. 

After launch, Athena will separate from the rocket and begin a roughly five-to-four-day cruise to the Moon’s orbit. The lander will orbit the Moon for approximately three to 1.5 days before its descent to the south pole. 

In Fall 2022, Research Engineer Ava Thrasher (AE 2022, M.S. AE 2024) began working on IM-2, developing new algorithms to guide Athena to the Shackleton crater using optical terrain relative navigation (TRN). Her approach looked at developing a crater detection algorithm (CDA) using image processing techniques that capture crater center locations on the Moon which are then used to determine Athena's position estimations. 

Then, she developed a crater identification algorithm (CIA) to match craters found in the image to a catalog of known lunar craters. By using CDA and CIA in tandem, Athena is able to estimate its location and orientation with a single photo, autonomously, and in real-time. 

“We wanted to strike a balance between creating something that would be done quickly on board, but also something that was reliable,” she explained. “We ended up using simple crater geometry and knowledge of the sun angle to render what we expect a crater to look like in the image.” 

The CDA finds craters by calculating a similarity score between the image and the rendered crater at each image pixel point. This process, also known as template matching, marks crater centers at points of very high similarity. CIA then uses these crater center locations to match them with known craters in a catalog. By matching pixel locations in an image to known three-dimensional positions on the Moon, the spacecraft is able to produce an estimation of its position. 

After two years of research and testing, Thrasher, Christian, and the Intuitive Machines team successfully demonstrated the CDA and CIA on synthetic imagery and Thrasher handed off the algorithms to Intuitive Machines to convert them into flight software for Athena. 

She first got involved with optical navigation (OPNAV) research after she took AE 4342: Senior Design with Prof. Christian as an undergraduate student. “I found optical navigation to be really interesting. I liked the idea of being able to figure out where you are and how you’re moving in real-time based on a picture,” she said. In Fall 2022, she started her first graduate semester at Tech and was a new member of SEAL, where she quickly began demonstrating the idea of detecting craters and prototyping the CDA and CIA programmed into Athena.  

After she graduated with her master’s degree in aerospace engineering in May 2024,  she loved what she did so much, that she decided to stay and work as a full-time research engineer in SEAL. Now, she’s gearing up to see her work make its way to the Moon.

“It's been really exciting and humbling to contribute to the massive task of putting a lander on the Moon. I never really appreciated the scale of work and collaboration needed to make it happen until I was lucky enough to be a part of it. I'll certainly be watching the launch and tracking the mission with great anticipation of both the engineering and scientific results,” said Thrasher. 

IM-1 Makes History

As part of a multi-year collaboration, Christian helped develop a key navigation algorithm for Intuitive Machines’ first space mission (IM-1) which launched a Nova-C lunar lander named Odysseus to the Malapert A crater on the Moon’s south pole region; about 11 miles away from IM-2’s targeted Shackleton crater. 

The IM-1 mission launched from Kennedy Space Center on February 15, 2024 and soft-landed on the Moon on February 22, 2024---making Odysseus the first U.S. lunar landing since the Apollo program and the first-ever successful commercial lunar landing. Odysseus had a rougher-than-expected soft landing due to an anomaly with the altimeter that was supposed to provide insight into the lander’s height above the lunar surface. In the absence of these altimeter measurements, Odysseus relied critically on the visual odometry technique that was jointly developed by Christian and Intuitive Machines. 

Despite these challenges, Odysseus captured images of the Moon during landing and operated on the lunar surface for 144 hours before entering standby mode. 

Prof. Christian and SEAL have more projects on the horizon to develop new technologies for exploring our Moon, other planets, asteroids, and the solar system. These technologies will enable future scientific missions to safely explore challenging destinations and answer scientific questions that were impossible with yesterday’s technology.