01 Jun 2019
A key element in the design of new and experimental aircraft, the world’s largest flight simulator could also help prepare the next astronauts to land on the Moon.
When the next people to set foot on the Moon are selected, with a planned arrival in 2024, those astronauts will need to learn how to fly the spacecraft they’ll land on the surface. But how do you design controls for a vehicle, then train for a flight that literally can't happen on Earth? With hardly any atmosphere and only one-sixth the gravity of Earth, the Moon will feel very different to a pilot behind the controls. For this, and many other cases where pilots should “fly” a vehicle before it can really be flown, you need NASA’s Vertical Motion Simulator.
The world’s largest motion flight simulator, the VMS moves within a ten-story tower at NASA’s Ames Research Center in California’s Silicon Valley. For a given simulation, the VMS motion platform uses one of five interchangeable cabs, which can be configured to recreate the cockpit of any aerospace vehicle – whether it exists today or is being designed for the future.
Driven by powerful motors and a system of hydraulics, the VMS offers an unequaled range of motion in all six degrees of freedom – the six ways that an aircraft or spacecraft moves. These are forward/backward, up/down and left/right, plus movement like an airplane’s nose pitching up or down, swinging side to side, or its wings rolling up or down.
The cab can move as much as 60 feet vertically and 40 feet horizontally as it simulates all phases of flight, including takeoff, cruise and landing. Designers and pilots of fighter jets, tilt-rotor aircraft, helicopters, the space shuttle, airships and more have had the chance to test out their respective vehicles for research before taking to the skies.
Lunar Landers, from Design to Training
NASA is working to send people to the Moon in a sustainable way and, as new lunar lander designs are developed, the VMS can be a key partner for testing and evaluation. The VMS is primarily a research simulator, where designers can test out their ideas and optimize the performance of aircraft and spacecraft. However, it can be valuable as a training simulator, as was the case for the space shuttle. Every NASA shuttle pilot received training in the VMS, and future Moon-bound astronauts may as well.
Already, the VMS can provide the closest thing to landing on the Moon we can experience on Earth. The interior of the lunar lander cab is laid out much like the Apollo Lunar Module with the pilot flying in a standing position and manipulating similar controls – though all hardware and software can be customized for new research. The VMS has already simulated two types of lunar flight – that of the Apollo Lunar Module and of the Altair, a lunar lander concept vehicle explored in the 2000s. The lunar lander cab features hand controllers that might be used in future lunar lander designs, and the simulator provides realistic visual and motion cues to the pilot. Since the cabs are reconfigurable, all hardware and software can be customized for new projects.
A Near-Flight-Like Experience
The motion of the VMS in those six degrees of freedom is based on real data from research on aircraft handling. This lets the VMS generate precise accelerations that result in a near-flight-like experience for pilots. Simulators with no motion or only tilting motion are useful for some development and training, but for the highest fidelity experience before actual flight, the VMS is the best option.
The out-the-window graphics – the computer-generated images that simulate the outside world and provide visual cues for the pilot – are highly customizable. The VMS maintains many representations of geographic locations in the United States and abroad. Three-dimensional models, such as aircraft, ground vehicles and buildings, are included in the graphics, and various weather and light conditions can be simulated. All the scenes can be modified, and new ones are created according to project needs.
Flexibility for a Wide Variety of Vehicles
The VMS was originally designed to support research in the development of new aircraft concepts – including vehicles that use vertical takeoff and landing. Over the decades it has been used to simulate a wide variety of vehicles, from fixed-wing and rotorcraft to newly designed and conceived experimental craft, such as NASA’s X-59 Quiet Supersonic Technology aircraft. The VMS was also used to model vehicle docking maneuvers with the International Space Station.
Researchers perform engineering studies at the VMS to evaluate the effectiveness of flight control systems, to rapidly test changes to aircraft design or evaluate different flight-control algorithms. It's used by major aerospace companies while developing concept aircraft to compete for contracts, and then later for flight control design refinements and to evaluate handling qualities for the winning design.
Flexibility in both hardware and software allows NASA’s VMS to simulate the flight of any aerospace vehicle. The flight controls, flight instruments and aircraft seats of each cab can be modified for different studies. Powerful computers and custom-designed systems enable the rapid development of high-fidelity, real-time simulation. This allows researchers to test handling qualities and tease out design problems and potential flaws before a vehicle is built, before it flies and, perhaps, before it lands on the Moon.
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(A) The Vertical Motion Simulator is the world’s largest motion flight simulator, moving within a ten-story tower at NASA’s Ames Research Center in California’s Silicon Valley. The cab can move as much as 60 feet vertically and 40 feet horizontally as it simulates all phases of flight, including takeoff, cruise and landing. Flexibility in both hardware and software allows the VMS to simulate the flight of any aerospace vehicle.
(B) NASA's Vertical Motion Simulator can provide the closest thing to landing on the Moon that we can experience on Earth. Inside one of five interchangeable cabs, a lunar lander cockpit is mocked up much like the Apollo Lunar Module, with the pilot flying in a standing position and manipulating similar controls.
(C) The Vertical Motion Simulator shown in motion timelapse.
(D) NASA is building the X-59 Quiet SuperSonic Technology demonstrator, or QueSST, which will demonstrate flight at supersonic speeds without producing a loud, disruptive sonic boom.