VIPER (rover)

Last updated

VIPER
VIPER lunar rover.jpg
Artist's impression of VIPER operating in darkness.
NamesVolatiles Investigating Polar Exploration Rover
Mission typeExploration, resource prospecting
Operator NASA
Website https://www.nasa.gov/viper
Mission duration100 days (planned) [1] [2] [3]
Spacecraft properties
Spacecraft typeRobotic lunar rover
Manufacturer NASA Ames Research Center
Dry mass430 kg (950 lb) [4]
Dimensions2.45 m (8 ft 0 in) in height,
1.53 m (5 ft 0 in) in length and width [5]
Start of mission
Launch dateSeptember 2025 (Canceled July 2024)
Rocket Falcon Heavy
Launch site Kennedy Space Center, LC-39A
Contractor SpaceX
Moon rover
Landing dateSeptember 2025 (canceled) [6]
Landing site Mons Mouton, South pole region [7] [2]
Instruments
Neutron Spectrometer System (NSS)
Near InfraRed Volatiles Spectrometer System (NIRVSS)
The Regolith and Ice Drill for Exploring New Terrain (TRIDENT)
Mass Spectrometer Observing Lunar Operations (MSolo)
  Blue Ghost
 

VIPER (Volatiles Investigating Polar Exploration Rover) is a cancelled lunar rover developed by NASA (Ames Research Center). The rover would have been 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 built on a NASA rover concept called Resource Prospector, which was cancelled in 2018. [8]

Contents

VIPER was to be carried aboard Astrobotic's Griffin lander as part of NASA's Commercial Lunar Payload Services (CLPS) initiative. [9]

Cancellation in 2024 - reasons

Amidst cost growth and delays to readiness of the rover and the Griffin lander, the VIPER program was ended in July 2024, with the rover planned to be disassembled and its instruments and components reused for other lunar missions. Before commencing disassembly, NASA announced they would consider "expressions of interest" from industry to use the "VIPER rover system at no cost to the government." [6] At the time of the announcement NASA expected to save $84 million by canceling the mission, which has cost $450 million so far. [10] The budgeted cost to build VIPER was $433.5 million, with $235.6 million budgeted to launch the lander. [11] The agency still plans to support the Griffin lander to arrive on the Moon in fall of 2025, though with a mass simulator in place of the VIPER rover. [12] NASA expects the primary objectives of VIPER to be fulfilled by an array of other missions planned for the next several years. [11]

Artist's conception of the VIPER rover on the Moon (Image courtesy of NASA Ames Research Center) Viper-ACD20-0047.jpg
Artist's conception of the VIPER rover on the Moon (Image courtesy of NASA Ames Research Center)

Objectives - Purpose

Orbital survey of the Moon taken by the Moon Mineralogy Mapper instrument on India's Chandrayaan-1 orbiter. Blue shows the spectral signature of hydroxide, green shows the brightness of the surface as measured by reflected infrared radiation from the Sun and red shows a mineral called pyroxene. Water Detected at High Latitudes on the Moon.jpg
Orbital survey of the Moon taken by the Moon Mineralogy Mapper instrument on India's Chandrayaan-1 orbiter. Blue shows the spectral signature of hydroxide, green shows the brightness of the surface as measured by reflected infrared radiation from the Sun and red shows a mineral called pyroxene.
The image shows the distribution of surface ice at the Moon's south pole (left) and north pole (right) as viewed by NASA's Moon Mineralogy Mapper (M ) spectrometer onboard India's Chandrayaan-1 orbiter. The image shows the distribution of surface ice at the Moon's south pole (left) and north pole (right).webp
The image shows the distribution of surface ice at the Moon's south pole (left) and north pole (right) as viewed by NASA's Moon Mineralogy Mapper (M ) spectrometer onboard India's Chandrayaan-1 orbiter.

The VIPER rover has a size similar to a golf cart (around 1.4 × 1.4 × 2 m), and would have been tasked with prospecting for lunar resources, especially for water ice, mapping its distribution, and measuring its depth and purity. [1] [2] The water distribution and form must be better understood before it can be evaluated as a potential resource within any evolvable lunar or Mars campaign. [13]

Proposed landing site of the Volatiles Investigating Polar Exploration Rover (VIPER) Proposed landing site of VIPER.gif
Proposed landing site of the Volatiles Investigating Polar Exploration Rover (VIPER)

The VIPER rover was to operate on the western edge of Nobile crater on Mons Mouton in the Moon's south pole region. [7] [14] The first ever rover with its own lighting source, [15] it was 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. [16] [2] In permanently shadowed locations, it would operate on battery power alone and would not be able to recharge them until it drives to a sunlit area. Its total operation time was planned to be 100 Earth days. [1] [2] [3]

History - Project management

The VIPER rover was part of the Lunar Discovery and Exploration Program managed by the Science Mission Directorate at NASA Headquarters, and was meant to support the crewed Artemis program. [2] NASA's Ames Research Center was managing the rover project. The hardware for the rover was designed by the Johnson Space Center, while the instruments were provided by Ames, Kennedy, and Honeybee Robotics. [2] The project manager was Daniel Andrews, [2] [17] and the project scientist was Anthony Colaprete, who was implementing the technology developed for the now cancelled Resource Prospector rover. [18] The estimated cost of the mission was US$250 million in October 2019. [3] NASA said on 3 March 2021 that the new lifecycle cost for the mission was US$433.5 million. [19]

Both the launcher and the lander were competitively provided through Commercial Lunar Payload Services (CLPS) contractors, with Astrobotic providing the Griffin lander to deliver the rover, and SpaceX providing the Falcon Heavy launch vehicle. [20] NASA was aiming to land the rover in September 2025 until the mission was canceled on 17 July 2024. [6] [21]

Rover assembly and preparation for launch

In February 2024 the final instrument, the TRIDENT drill, was installed into the rover. [22] Later on 28 February 2024, VIPER Project Manager Dan Andrews announced that all the rover's scientific instruments were installed, and that it was more than 80% built. [23] Further progress was reported in April 2024, remaining on track for launch later in the year. [24] The rover moved to the environmental testing phase in May. [25]

Science background

Data obtained by Lunar Prospector, [26] Lunar Reconnaissance Orbiter, Chandrayaan-1, and the Lunar Crater Observation and Sensing Satellite, revealed that lunar water is present in the form of ice near the lunar poles, especially within permanently shadowed craters in the south pole region, [27] [28] and present in the form of hydrated minerals in other high-latitude locations. [29]

Water may have been delivered to the Moon over geological timescales by the regular bombardment of water-bearing comets, asteroids and meteoroids, [30] or continuously produced in situ by the hydrogen ions (protons) of the solar wind impacting oxygen-bearing minerals. [26] The physical form of the water ice is unknown, but some studies suggest that it is unlikely to be present in the form of thick, pure ice deposits, and may be a thin coating on soil grains. [31] [32] [28]

If it is possible to mine and extract the water molecules (H
2
O
) 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. [33] 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 2450 metric tons of processed lunar water, generating US$2.4 billion of revenue annually. [34]

Science payload

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: [2] [3] [35]

The NIRVSS instrument VIPER rover nirvss.jpg
The NIRVSS instrument
Instrument nameAbbr.ProviderFunction [36]
Neutron Spectrometer System
NSS
Ames Research Center (NASA)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. [13]
The Regolith and Ice Drill for Exploring New Terrain
TRIDENT
1-m drill will obtain subsurface samples.
Near InfraRed Volatiles Spectrometer System
NIRVSS
Ames Research Center (NASA)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. [13]
Sub-systems: Spectrometer Context Imager (a broad-spectrum camera); Longwave Calibration Sensor (measures surface temperature at very small scales).
Mass Spectrometer Observing Lunar Operations
MSolo
Kennedy Space Center (NASA)Analyze mineral and volatile composition. Measures the mass-to-charge ratio of ions to elucidate the chemical elements contained in the sample.

See also

Related Research Articles

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References

  1. 1 2 3 Coldewey, Devin (25 October 2019). "NASA's VIPER lunar rover will hunt water on the Moon in 2022". TechCrunch. VIPER is a limited-time mission; operating at the poles means there's no sunlight to harvest with solar panels, so the rover will carry all the power it needs to last 100 days there.
  2. 1 2 3 4 5 6 7 8 9 Loff, Sarah (25 October 2019). "New VIPER Lunar Rover to Map Water Ice on the Moon". NASA.PD-icon.svg This article incorporates text from this source, which is in the public domain .
  3. 1 2 3 4 Bartels, Meghan (25 October 2019). "NASA Will Launch a Lunar VIPER to Hunt Moon Water in 2022". Space.com. Retrieved 13 April 2021.
  4. Colaprete, Anthony (17 August 2020). "VIPER: A lunar water reconnaissance mission" (PDF). NASA. Retrieved 25 August 2020.PD-icon.svg This article incorporates text from this source, which is in the public domain.
  5. "NASA's Next Lunar Rover Progresses Toward 2023 Launch". NASA. 24 February 2021. Retrieved 5 March 2021.PD-icon.svg This article incorporates text from this source, which is in the public domain.
  6. 1 2 3 "NASA Ends VIPER Project, Continues Moon Exploration - NASA" . Retrieved 17 July 2024.
  7. 1 2 Wright, Ernie; Ladd, David; Colaprete, Anthony; Ladd, David (20 September 2021). "NASA Scientific Visualization Studio". SVS. Retrieved 27 October 2023.
  8. Bartels, Meghan (16 October 2019). "Moon VIPER: NASA Wants to Send a Water-Sniffing Rover to the Lunar South Pole in 2022". Space.com. Retrieved 13 April 2021.
  9. "NASA Selects Astrobotic to Fly Water-Hunting Rover to the Moon". NASA. 11 June 2020. Retrieved 14 June 2020.PD-icon.svg This article incorporates text from this source, which is in the public domain .
  10. Tingley, Brett (17 July 2024). "NASA cancels $450 million VIPER moon rover due to budget concerns". Space.com. Archived from the original on 17 July 2024. Retrieved 17 July 2024.
  11. 1 2 Boyle, Alan (17 July 2024). "NASA Stops Work on VIPER Moon Rover, Citing Cost and Schedule Issues". Universe Today. Archived from the original on 17 July 2024. Retrieved 17 July 2024.
  12. NASA Video (17 July 2024). Exploration Science Program Update (July 17, 2024) (Press Conference). Retrieved 18 July 2024 via YouTube.
  13. 1 2 3 Elphic, Richard; Colaprete, Anthony; Andrews, Daniel (2018). "Resource Prospector: Evaluating the ISRU potential of the lunar poles". 42nd COSPAR Scientific Assembly. 42. Bibcode:2018cosp...42E.981E.
  14. "NASA's Artemis Rover to Land Near Nobile Region of Moon's South Pole". NASA. 20 September 2021. Retrieved 20 September 2021.PD-icon.svg This article incorporates text from this source, which is in the public domain .
  15. "NASA Replans CLPS Delivery of VIPER to 2024 to Reduce Risk". NASA . 18 July 2022. Archived from the original on 17 July 2024. Retrieved 18 July 2022.
  16. Hautaluoma, Grey; Johnson, Alana (28 October 2019). "New VIPER lunar rover to map water ice on the moon". PhysOrg.
  17. Moon, Mariella (26 October 2019). "NASA's VIPER rover will look for water ice on the Moon". ENGADGET.
  18. Foust, Jeff (27 October 2019). "NASA confirms plans to send prospecting rover to the moon". SpaceNews.
  19. "VIPER lunar rover mission cost increases". SpaceNews. 3 March 2021. Retrieved 5 March 2021.
  20. Foust, Jeff (13 April 2021). "Astrobotic selects Falcon Heavy to launch NASA's VIPER lunar rover". SpaceNews. Retrieved 13 April 2021.
  21. Harris, Rainier (17 July 2024). "NASA Cancels Rover Mission Set to Search for Ice on Moon". Bloomberg.com. Retrieved 18 July 2024.
  22. "TRIDENT Drill Integrated into NASA's VIPER Rover, Completing its Scientific Arsenal". February 2024.
  23. Lea, Robert (3 March 2024). "NASA's ice-hunting VIPER moon rover getting ready to slither to the launch pad". Space.com. Retrieved 4 March 2024.
  24. "NASA's VIPER Gets Its Head and Neck – NASA" . Retrieved 18 April 2024.
  25. "Mission Manager Update: VIPER Rover Approved to Move into Environmental Testing! - NASA". 14 May 2024. Retrieved 15 May 2024.
  26. 1 2 "NASA – Lunar Prospector". lunar.arc.nasa.gov. Archived from the original on 14 September 2016. Retrieved 25 May 2015.PD-icon.svg This article incorporates text from this source, which is in the public domain .
  27. "NASA Looking to Mine Water on the Moon and Mars". Soderman NASA's Solar System Exploration Research Virtual Institute.PD-icon.svg This article incorporates text from this source, which is in the public domain .
  28. 1 2 Neish, C. D.; Bussey, D. B. J.; Spudis, P.; Marshall, W.; Thomson, B. J.; Patterson, G. W.; Carter, L. M. (13 January 2011). "The nature of lunar volatiles as revealed by Mini-RF observations of the LCROSS impact site". Journal of Geophysical Research: Planets. 116 (E01005): 8. Bibcode:2011JGRE..116.1005N. doi: 10.1029/2010JE003647 .
  29. Pieters, C. M.; Goswami, J. N.; Clark, R. N.; Annadurai, M.; Boardman, J.; Buratti, B.; Combe, J.-P.; Dyar, M. D.; Green, R.; Head, J. W.; Hibbitts, C.; Hicks, M.; Isaacson, P.; Klima, R.; Kramer, G.; Kumar, S.; Livo, E.; Lundeen, S.; Malaret, E.; McCord, T.; Mustard, J.; Nettles, J.; Petro, N.; Runyon, C.; Staid, M.; Sunshine, J.; Taylor, L. A.; Tompkins, S.; Varanasi, P. (2009). "Character and Spatial Distribution of OH/H2O on the Surface of the Moon Seen by M3 on Chandrayaan-1". Science. 326 (5952): 568–572. Bibcode:2009Sci...326..568P. doi: 10.1126/science.1178658 . PMID   19779151. S2CID   447133.PD-icon.svg This article incorporates text from this source, which is in the public domain .
  30. Elston, D. P. (1971). "Character and Geologic Habitat of Potential Deposits of Water, Carbon and Rare Gases on the Moon". Geological Problems in Lunar and Planetary Research: 441. Bibcode:1971gplp.conf..441E.
  31. Jozwiak, L. M.; Patterson, G. W.; Perkins, R. (2019). "Mini-RF Monostatic Radar Observations of Permanently Shadowed Crater Floors". Lunar ISRU 2019 – Developing a New Space Economy Through Lunar Resources and Their Utilization. 2152: 5079. Bibcode:2019LPICo2152.5079J. ISSN   0161-5297.
  32. Nozette, Stewart; Spudis, Paul; Bussey, Ben; Jensen, Robert; Raney, Keith (January 2010). "The Lunar Reconnaissance Orbiter Miniature Radio Frequency (Mini-RF) Technology Demonstration". Space Science Reviews. 150 (1–4): 285–302. Bibcode:2010SSRv..150..285N. doi:10.1007/s11214-009-9607-5. S2CID   54041415.
  33. Anand, M.; Crawford, I. A.; Balat-Pichelin, M.; Abanades, S.; van Westrenen, W.; Péraudeau, G.; Jaumann, R.; Seboldt, W. (2012). "A brief review of chemical and mineralogical resources on the Moon and likely initial in situ resource utilization (ISRU) applications". Planetary and Space Science. 74 (1): 42–48. Bibcode:2012P&SS...74...42A. doi:10.1016/j.pss.2012.08.012.
  34. David, Leonard (15 March 2019). "Moon Mining Could Actually Work, with the Right Approach". Space.com.
  35. "Lunar Exploration Science Objectives" (PDF). NASA. 15 August 2019. Retrieved 22 September 2021.PD-icon.svg This article incorporates text from this source, which is in the public domain .
  36. "Where's the Water? Two Resource-Hunting Tools for the Moon's Surface". NASA. 10 March 2019.PD-icon.svg This article incorporates text from this source, which is in the public domain .