Work on the Lunar Entry and Approach Platform for Research on Ground, or LEAPFROG, began in the fall of 2006 with a team of 15 students. The goal of the project was to build a low-cost lunar lander that could be used repeatedly without being rebuilt.
Naohiro Horie, a first year graduate student majoring in astronautics engineering and the engineer responsible for the main jet engine and altitude control system, explained that one way the team is trying to reach this goal is by using less expensive materials. “The reason why we use air is because the key thing for this project is repeatability and low cost. So, air is not so expensive, and we can use the altitude control system over and over,” he said of the paintball-like tanks of compressed air that connect with six thrusters to control the altitude of the lander.
David Barnhart is the project leader who works at the Information Sciences Institute, the independent research facility affiliated with USC where the lander is being built. He says the group is following a philosophy called “build a little, test a little and then fly a little” as they build the Generation 0 prototype, which was inspired by the NASA Apollo lander.
“It actually is a reasonable approach because what it really does is it boils down to prototyping things and then testing them in a stepwise fashion so you are making incremental changes,” Barnhart explained. “Also, you make incremental increases in knowledge about how the system works, rather than just sitting in front of a design.”
Omair Rahman, a fourth year graduate student majoring in astronautics engineering who has been on the project since it began, says work on the lander has gone fairly smoothly, though there have been some hiccups here and there. He said that the base of the prototype was built and had undergone some testing during the 2006-07 academic year. They were also able to build one of the six major sub-systems during that time, he added.
“After that, we went in a slump for a year because [we had to work on] one of the systems, the guided navigation and controls,” Rahman said. “We [also] lost students in the middle, so that was bad,” he added.
Barnhart said that students leaving and joining the project from year to year is not so bad. “What’s good and bad about students coming in is that they get some intellectual experience and then they document that,” he said. “Then the next level of students comes in, and essentially these students are standing on the shoulders of everyone that came before them.”
Barnhart said the group has instituted a system where each student creates a blog that is available to everyone involved in the project. He said that the transition time between each group of students has shortened with the larger quantity of information available to them upon entering the program.
“[The students] can look at it when they come in and they can go through, ‘Oh, this happened,’ or ‘That was a problem that occurred,’ or ‘This is why we designed something this way,’” he said. “We have documentation of everything that has happened.”
The shift in teams has not put any students at a disadvantage when it comes to hands-on experience and testing. “We have done tests every single semester,” Barnhart explained. “So every student team, no matter if they are new or if they’ve been here for a while, gets experience in real testing.”
For the current team of five who began in fall 2008, testing has been on the jet engine and altitude control systems. “[It] is awesome to listen to it and to be out there with it because it’s a real jet engine,” said with an eager smile. “And the ACS tanks are basically no more than paintball tanks.”
There are some dangers associated with each system, Barnhart warned. “We had to create a system that allows [the tanks] to fire very, very quickly, and it turns out it’s a very high pressure system,” he said. “So there are hazards associated with that system as well as the jet engine system.”
Though the project has gone through several systems tests — including a stability test where the lander was suspended and the altitude thrusters were fired (see video below) — Barnhart has high hopes that the current group of students will be the ones to put the prototype in the air. “They started in the beginning of the fall, and they are the ones that, I believe, are going to get us through our first pre-flight,” he said.
“It actually is a reasonable approach because what it really does is it boils down to prototyping things and then testing them in a stepwise fashion so you are making incremental changes,” Barnhart explained. “Also, you make incremental increases in knowledge about how the system works, rather than just sitting in front of a design.”
Omair Rahman, a fourth year graduate student majoring in astronautics engineering who has been on the project since it began, says work on the lander has gone fairly smoothly, though there have been some hiccups here and there. He said that the base of the prototype was built and had undergone some testing during the 2006-07 academic year. They were also able to build one of the six major sub-systems during that time, he added.
“After that, we went in a slump for a year because [we had to work on] one of the systems, the guided navigation and controls,” Rahman said. “We [also] lost students in the middle, so that was bad,” he added.
Barnhart said that students leaving and joining the project from year to year is not so bad. “What’s good and bad about students coming in is that they get some intellectual experience and then they document that,” he said. “Then the next level of students comes in, and essentially these students are standing on the shoulders of everyone that came before them.”
Barnhart said the group has instituted a system where each student creates a blog that is available to everyone involved in the project. He said that the transition time between each group of students has shortened with the larger quantity of information available to them upon entering the program.
“[The students] can look at it when they come in and they can go through, ‘Oh, this happened,’ or ‘That was a problem that occurred,’ or ‘This is why we designed something this way,’” he said. “We have documentation of everything that has happened.”
The shift in teams has not put any students at a disadvantage when it comes to hands-on experience and testing. “We have done tests every single semester,” Barnhart explained. “So every student team, no matter if they are new or if they’ve been here for a while, gets experience in real testing.”
For the current team of five who began in fall 2008, testing has been on the jet engine and altitude control systems. “[It] is awesome to listen to it and to be out there with it because it’s a real jet engine,” said with an eager smile. “And the ACS tanks are basically no more than paintball tanks.”
There are some dangers associated with each system, Barnhart warned. “We had to create a system that allows [the tanks] to fire very, very quickly, and it turns out it’s a very high pressure system,” he said. “So there are hazards associated with that system as well as the jet engine system.”
Though the project has gone through several systems tests — including a stability test where the lander was suspended and the altitude thrusters were fired (see video below) — Barnhart has high hopes that the current group of students will be the ones to put the prototype in the air. “They started in the beginning of the fall, and they are the ones that, I believe, are going to get us through our first pre-flight,” he said.
Once the small-scale Generation 0 prototype has passed its flight test, the group can begin working on the Generation 1 lander, a larger version with even more capabilities.
“I’m so excited,” Horie said. “This is a very unique project — a lunar lander!”
Hands-on experience essential to education, but uncommon in curriculum
The five students currently working on the LEAPFROG lunar lander prototype each entered the project looking for hands-on experience. Omair Rahman said he stumbled upon the project while looking for a way to put his electrical engineering background to the test.
“I was looking around campus, looking for somebody starting some project that has real electronics hardware,” Rahman said. “I was walking by the aeronautics building and they had a big poster, ‘Help needed.’ They were starting a new project.”
Horie had a similar experience getting involved with the project. “I was looking for a research opportunity for hands-on experience because it is very crucial,” he said. “I found this project on the web site and I talked to the leader, David [Barnhart].”
Barnhart says that this hands-on experience is crucial in the students’ engineering education. The process of “build a little, test a little” gives students a chance to see first hand their successes and failures, he said.
“We’ve done incremental tests and almost all the tests have achieved a level of success as either by meeting a performance metric we wanted to have, or by something going wrong, which finally introduces it to the students like, ‘Oh wow, that’s why that didn’t work right,’ he said. “It’s something that I could never teach or that no curriculum could teach. It’s a gut level instinct that you only get when something doesn’t work right.”
But for something that seems so crucial to an engineering education, there are no colleges in the United States working at the same level this group of USC students is working at. “I have not heard about any other school in the United States doing anything associated with a lunar lander research vehicle or a lunar prototype vehicle like this,” Barnhart said. “There’s one group in Japan at the University of Tokyo that is thinking of doing something similar to this,” he added. “But that’s all we’ve heard of.”
He explained that there are some Southern California schools that are working on smaller components of the lander system. “There are teams that are working on, say, RC model helicopters and they are doing G and C control tests. And there are teams that are developing propulsion systems that could be used for space crafts,” he said.
“But [there is] nothing like an integrated flight vehicle that combines air-breathing propulsion and cold gas systems and guidance control that you would use on a space craft all being put together to demonstrate a lunar landing profile,” he said. “It’s a system integrated test of something that … as far as I know, will be the first student-built lunar lander prototype vehicle in the country,” he added.
Barnhart said that the only other group that has succeeded at creating and flying this type of lander is NASA Ames. “They did it in 18 months and spent $2 million. I think we are actually doing pretty good,” he said with a smile.
The materials for the Generation 0 prototype have cost $5,000 to $8,000 a semester, Barnhart said, and the total cost has been more than $50,000 since the project began in 2006. The money comes from USC research grants, ISI research grants and donations. No funding for the projects comes from USC tuition, he said.
