Artist's impression of the VIPER lunar rover operating in darkness
|Mission type||Reconnaissance, resource prospecting|
|Mission duration||≈100 Earth days.|
|Spacecraft type||lunar rover|
|Manufacturer||Johnson Space Center|
|Start of mission|
|Launch date||2022 (planned)|
|Rocket||[to be determined]|
|Landing site||south pole region|
The VIPER (Volatiles Investigating Polar Exploration Rover) is a lunar rover by NASA planned to be delivered to the surface of the Moon as early as December 2022. The rover will be tasked with prospecting for lunar resources in permanently shadowed areas in the lunar south pole region, especially by mapping the distribution and concentration of water ice. The mission builds on a previous NASA rover concept called Resource Prospector, which was cancelled in 2018.
The VIPER rover, currently under development, will have a size similar to a golf cart (around 1.4 m × 1.4 m × 2 m), and will be tasked with prospecting for lunar resources, especially for water ice, mapping its distribution, and measuring its depth and purity. The water distribution and form must be better understood before it can be evaluated as a potential architectural element within any evolvable lunar or Mars campaign.
The VIPER rover is part of the Lunar Discovery and Exploration Program managed by the Science Mission Directorate at NASA Headquarters, and it is meant to support the crewed Artemis program. NASA's Ames Research Center is managing the rover project. The hardware for the rover is being designed by the Johnson Space Center, while the instruments are provided by Ames, Kennedy, and Honeybee Robotics. The project manager is Daniel Andrews, and the project scientist is Anthony Colaprete, who is implementing the technology developed for the now cancelled Resource Prospector rover. The estimated cost of the mission is US$250 million.
The VIPER rover will operate at a south pole region yet to be determined. VIPER is planned to rove several kilometers, collecting data on different kinds of soil environments affected by light and temperature —those in complete darkness, occasional light and in constant sunlight. Once it enters a permanently shadowed location, it will operate on battery power alone and will not be able to recharge them until it drives to a sunlit area. Its total operation time will be approximately 100 Earth days.
Both the launcher and the lander to be used, will be competitively provided through the Commercial Lunar Payload Services (CLPS) contractors. NASA is aiming at landing the rover as early as December 2022.
Data obtained by the Luna 24, Lunar Reconnaissance Orbiter, Chandrayaan-1, and the Lunar Crater Observation and Sensing Satellite, revealed that lunar water is distributed widely (if thinly) across the Moon's surface, especially within permanently shadowed craters in the south pole region.
Water may have been delivered to the Moon over geological timescales by the regular bombardment of water-bearing comets, asteroids and meteoroids, or continuously produced in situ by the hydrogen ions (protons) of the solar wind impacting oxygen-bearing minerals. The water ice is unlikely to be present in the form of thick, pure ice deposits, but as thin coating on soil grains.
If able to mine and extract the water molecules (H
2O) in large amounts, it can be broken down to its elements, namely hydrogen and oxygen, and form molecular hydrogen (H
2) and molecular oxygen (O
2) to be used as rocket bi-propellant or produce compounds for metallurgic and chemical production processes. Just the production of propellant, was estimated by a joint panel of industry, government and academic experts, identified a near-term annual demand of 450 metric tons of lunar-derived propellant equating to 2,450 metric tons of processed lunar water, generating US$2.4 billion of revenue annually.
The VIPER rover will be equipped with a drill and three analyzers. The Neutron Spectrometer System (NSS), will detect sub-surface water from a distance, then, VIPER will stop at that location and deploy a 1 m (3 ft 3 in) drill called TRIDENT to obtain samples to be analyzed by its two onboard spectrometers: 
|Neutron Spectrometer System||
|Detect sub-surface hydrogen (potentially water) from a distance, suggesting prime sites for drilling. It measures the energy released by hydrogen atoms when struck by neutrons. Originally developed for the Resource Prospector rover.|
|Regolith and Ice Drill for Exploring New Terrain||
|1-m drill will obtain subsurface samples.|
|Near InfraRed Volatiles Spectrometer System||
|NASA's Ames Research Center||Analyze mineral and volatile composition; determine if the hydrogen it encounters belong to water molecules (H2O) or to hydroxyl (OH-). Originally developed for the Resource Prospector rover.|
Sub-systems: Spectrometer Context Imager (a broad-spectrum camera); Longwave Calibration Sensor (measures surface temperature at very small scales).
|Mass Spectrometer Observing Lunar Operations||
|NASA's Kennedy Space Center||Analyze mineral and volatile composition. Measures the mass-to-charge ratio of ions to elucidate the chemical elements contained in the sample.|
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