Draper Laboratory - Landing on the Moon

If a team competing for the Google Lunar X PRIZE puts a spacecraft on the Moon, it won’t win the $20 million first prize unless it lands safely, travels at least 500 meters, and sends back data to Earth, which is why the guidance system that Draper Laboratory is developing for the Rocket City Space Pioneers (RCSP) is so critical to success in the competition.

Draper’s history with developing guidance, navigation, and control (GN&C) systems in space began with the Apollo missions, and continues today with major NASA programs like the space shuttle and the International Space Station as well as commercial providers and the U.S. Defense Department.

In the 1960s when Draper built the GN&C system for Apollo, the astronauts on board handled the task of watching for hazards such as craters or rocks that could damage or destroy their spacecraft.

As RCSP targets a Moon landing, the task previously handled by human eyes will be automated by sensors and software that Draper is designing. Draper is leveraging technology that it has developed for NASA on programs ranging from Apollo in the 1960s to the current Autonomous Landing and Hazard Avoidance (ALHAT) effort as well as internal research on landing and surface mobility. While Apollo weighed about 33,000 pounds and was roughly the size of a bus, the RCSP lander will likely be about the size of a file cabinet and weigh less than 700 pounds – about 98 percent less than the original pioneering system.

Smaller space systems have their upside – they are less expensive to build, have less mass, and require less power. The unmanned nature of the Google Lunar X PRIZE mission also makes the hardware development less challenging because there is no need to build systems capable of protecting astronauts. But the RCSP lander’s smaller size also means that there are fewer or less powerful sensors to assist with a safe landing and navigation on a planet’s surface.

However, guidance technology has come a long way over the more than four decades that Draper has worked on GN&C systems. The biggest change is with computing power. Though it was instrumental in helping astronauts reach the Moon safely, the Apollo flight computer was less powerful than some of today’s handheld calculators -- though far more robust in order to withstand the space environment and protect the astronauts on board.

In one instance during the Apollo 11 landing, Neil Armstrong looked out the window and saw that the planned landing site was too rocky for a safe touchdown. Armstrong was able to make the quick decision to find an alternate landing spot, less than 30 seconds before he would have run out of fuel.

The RCSP flight computer will be far more powerful than that of Apollo – like comparing the handheld calculator to a 1990s desktop PC. Based on Draper’s lunar landing research, the RCSP lander will be able to use its sensors and computer to spot hazards and avoid them autonomously, while landing more precisely than its manned predecessors.

The RCSP lander will feature much smaller, yet more accurate, versions of the inertial measurement unit, star tracker, and altimeter that were used on Apollo. In the case of the star tracker, the RCSP lander will automate a function that was previous handled by humans looking through telescopes. All these advancements make for a much more robust and precise solution, allowing RCSP’s lander to touch down more accurately and safely than any previous mission to the Moon.

Draper Laboratory Lunar Landing Research

Draper engineers conduct lunar landing research in the laboratory’s simulator (Click for High Res Photo)
(photo credit: John Earle) Draper Laboratory

Draper is a not-for-profit, engineering research and development organization dedicated to solving critical national problems in security, space systems, biomedical systems, and energy. Core capabilities include guidance, navigation and control; miniature low power systems; highly reliable complex systems; information and decision systems; autonomous systems; biomedical and chemical systems; and secure networks and communications.

By Pete Paceley, Draper Program Manager, Huntsville and Bobby Cohanim, Draper RCSP Technical Director, Cambridge 

 

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