William Allen, Senior Engineer, Spacecraft Mechanical Engineering Section, Jet Propulsion Laboratory, Pasadena, CA
- Wednesday, 26 October 2011
William Allen, senior engineer at the Jet Propulsion Laboratory, is the mechanical systems design lead on the Mars Science Laboratory (MSL), NASA’s biggest, most expensive, and most capable Mars rover. The rover is set to launch in November 2011.
NASA Tech Briefs: NASA is gearing up for the Mars Science Laboratory to launch in late November. Can you set the stage for us? What is the mission?
William Allen: The Mars Science Laboratory is our next rover that we’re sending to Mars. It’s significantly more capable and massive than the previous rovers that we’ve sent up. It’s nuclear-powered, so we won’t have some of the challenges that we’ve had with solar power. It’s designed to be a science laboratory versus the predecessors that were more like mobile geologists. This’ll actually be a mobile science laboratory. There are 10 instruments on board to facilitate that.
NTB: Can you take us through some of the key capabilities of this Mars Science Laboratory?
Allen: With the size alone, it’ll be able to traverse more difficult terrain. It is designed to drive over objects about 25 inches to thirty inches in size, so that’s different than before. It has a robotic arm, and there is a suite of tools and instruments on the arm itself. For the first time, we will not only collect samples, but we will deposit and analyze the samples within the rover itself.
NTB: What kinds of questions are we trying to answer with this mission?
Allen: Specific questions regarding Martian history, if you will, its current makeup, and its past makeup. The overall Mars program [mission] is to eventually put a person on Mars, so this is the Lewis and Clark effort of pioneering and doing the research to further our knowledge about the planet.
NTB: At the time of this interview (Sept. 2011), what parts of the instrument and spacecraft still need to be finished and integrated?
Allen: Considering it’s a November launch, things are getting down to the wire. The spacecraft is currently being stacked and integrated out in Cape Canaveral as we speak. There are some typical last-minute challenges, but certainly the design is done, and the hardware is fabricated. There might be small things that need fixing or adding, or even things may need to be taken away, at this late hour.
NTB: The rover has to survive a pretty dramatic atmospheric entry and landing. How does the design enable it to withstand that?
Allen: This is something we have a lot of experience with, in terms of entering into another planet’s atmosphere and landing on the surface. It’s about the most difficult space exploration you can do. Orbiting is fairly straightforward, and flybys are fairly straightforward. When landing on another planet, you have to get from about 30,000 miles per hour down to zero, in just a matter of seconds. You’re right. It’s a harsh environment, and it’s a sequence of events and utilizing different technology to enable this.
A heat shield is a primary component of that, much like the shuttle or the reentry capsules that astronauts use here. We have similar equipment on our spacecraft: a heat shield with special materials that withstand high temperatures and deflect the heat away from the actual spacecraft or the rover.
NTB: What are the most exciting possibilities for this mission?
Allen: Personally, my excitement comes when things work: if the rover lands and is functional and driving around, and being able to perform its science. That’s what makes me excited. As a mechanical engineer and designer, that’s my involvement in the program.
NTB: What were the engineering challenges when you were building such a complex rover?
Allen: Because of the size and the number of instruments, it’s an interface nightmare. We’re trying to integrate instruments from different partners, different countries, and different goals. We’re trying to do all that on board, all on one vehicle. Systematically it becomes a challenge to bring all that together. When do you do which science? You have to share all of the resources. We’re restricted in hours of operation based on temperatures. Integrating that and making it work as one vehicle is a significant challenge.