In Depth

Launch: Late 2024

Landing site: Nobile Region of Moon's South Pole

Delivery to the Moon: Launch vehicle and lander provided by a NASA Commercial Lunar Payload Services partner

Mission duration: 100 Earth days, covering 3 cycles of lunar day and night

Distance goal: 12 miles (20 kilometers)

Rover size: Similar to a golf cart: 5 feet by 5 feet by 8 feet (1.5 meters by 1.5 meters by 2.5 meters) and 992 pounds (450 kilograms)

Onboard instruments: 3 spectrometers and a 3.28-foot (1-meter) drill

Power: Solar-charged battery, peak power of 450 watts

Top speed: 0.45 mph (0.72 kph)

Communications: X-band direct-to-Earth (no relay) over the Deep Space Network

Humans have been studying the Moon from afar for thousands of years, but it wasn't until NASA sent the first people there with the Apollo 11 mission in 1969 that its soils could be examined in detail. The Moon rocks the astronauts brought home for laboratory analysis were found to be bone dry – but we now know that those conclusions did not tell the whole story of water on the Moon.

Beginning in the early 1990s, a series of orbiter and impactor missions began to piece together a more promising picture, culminating in NASA's 2009 discovery confirming the presence of subsurface ice at the lunar South Pole.

VIPER picks up on this journey. As NASA's first mobile robotic mission to the Moon, VIPER will directly analyze ice on the surface and subsurface of the Moon at varying depths and temperature conditions within four main soil environments. The data VIPER transmits back to Earth will be used to create resource maps, helping scientists determine the location and concentration of ice on the Moon and the forms it’s in, such as ice crystals or molecules chemically bound to other materials.

As it prospects for ice from the surface, VIPER's findings will inform future landing sites under Artemis by helping to determine locations where water and other  resources can be harvested to support a long-term presence on the Moon.

Bringing everything we need from Earth for long-term exploration in space would be very costly, so using resources found on the Moon, like water, could be a game-changer for human space exploration to the Moon, Mars, and beyond.

The VIPER team faces some brand new challenges operating a rover on the Moon, different from those tackled by previous rover missions to Mars.

Extreme temperatures: The rover's hardware will need to withstand surface temperatures varying by 500 degrees Fahrenheit between sunlight and shade. A battery, heat pipes, and radiators will help keep the rover’s parts from freezing or overheating.

Real-time drivers: The Moon is much closer to Earth than Mars, so there will be little delay when transmitting commands to the rover. That means drivers on Earth can operate VIPER interactively. With a lot of ground to cover on a tight schedule over complex terrain, the drivers' efforts will be key. Because of the dim-to-dark lighting at the South Pole, drivers will have to operate in places where we do not have good "scouting" images from orbit. Computer simulations of the mission will allow them to practice this critical operation before launch.

Mobility: We can't be exactly sure what the soil in the Moon's polar regions will be like – hard and compacted, fluffy, or somewhere in between. As a result, VIPER is designed for unprecedented agility. The rover can drive sideways or diagonally, spin in a circle and move in any direction without changing the way it's facing. If it encounters soft soils, it will even be able to walk its wheels by moving each wheel independently to free itself.

Complex route planning: The extreme swings in light and dark at the poles of the Moon are nothing like those on Earth or Mars – and produce extremely long and fast-moving shadows. The solar-powered VIPER must retreat from these advancing shadows as it seeks out the right territory to sample while maintaining communications with Earth. Periods of darkness will be long – up to one Earth week – so VIPER will be periodically parked in identified safe havens at high elevations where the darkness only lasts four days. Combining all these needs makes for complicated route planning.  

First rover with headlights: VIPER will explore inside dark craters where the Sun never reaches, making it the first NASA rover to need headlights. However, rover engineers face a brand new challenge in building a lighting-plus-camera system to operate in the Moon's harsh temperatures and extreme conditions of light and dark.

The VIPER rover will be delivered to the Moon by Astrobotic's Griffin lander and SpaceX's Falcon Heavy launch vehicle as part of NASA's Commercial Lunar Payload Services, or CLPS, initiative. Astrobotic will be responsible for integrating VIPER onto their lander, selecting a launch provider, launching from Earth, and landing on the Moon.  

VIPER will be the largest and heaviest payload delivered by a CLPS provider, demonstrating the capability of industry partners to fly a range of payloads to the Moon for NASA.

Through CLPS, commercial delivery missions – including VIPER and many other missions with planned payloads – will perform science experiments, test technologies, and demonstrate capabilities to help NASA explore the Moon and prepare for human missions.  

VIPER's delivery must meet a critical timing window. The commercial partner must land VIPER on the Moon at the start of the “summer season” on the South Pole when periods of sunlight are longest to support rover operations.

The phases of the VIPER mission include:

VIPER is a collaboration within and beyond the agency. VIPER is part of the Lunar Discovery and Exploration Program managed by the Science Mission Directorate at NASA Headquarters in Washington. NASA's Ames Research Center in California's Silicon Valley is managing the VIPER mission, as well as leading the mission's science, systems engineering, real-time rover surface operations, and flight software. The rover hardware is being designed and built by NASA's Johnson Space Center in Houston, while the instruments are provided by Ames, Kennedy Space Center in Florida, and commercial partner Honeybee Robotics in Altadena, California. SpaceX's Falcon Heavy launch vehicle and Astrobotic's Griffin lander will deliver VIPER to the surface of the Moon as part of NASA's Commercial Lunar Payload Services initiative, delivering science and technology payloads to and near the Moon.