Sensor Specifications

Michael Kline
spacemtk@utxvms.cc.utexas.edu
John Opiela
opiela@ccwf.cc.utexas.edu
August 1995

Optical Imaging Subystems

The optical imaging system is second in importance only to the oxygen production plant. The imaging system must transmit images to Earth of the lunar surface during lander descent, the lunar surface around the lander, and operations of the soil sampler mechanism and chemical plant reactor. Off-Moon targets, espescially a full Earth after lunar sunset, are of interest, but not of primary importance. The camera field of view should be controlled by a combination of optics and pointing.

Color images in "full motion" (30 frames per second) are desirable, as are stereo images. However, due to the lack of moving targets on the Moon, slow camera panning combined with a 10-15 frame per second data rate should provide "full motion" quality images. Stereo images are not important for the lander, but the rover may benefit from a stereoscopic view of the surrounding terrain. The design should emphasize current solid-state video technology. The imaging system should be able to operate for a minimum of 10 hours after lunar sunset (1960's Surveyor technology achieved 15+ hours after sunset operation).

In addition to the lander and rover cameras, a third or fourth small ejectable camera may be desireable to capture "live" images of the lander approaching and landing on the lunar surface. This camera would have to be light, inexpensive, and capable of viewing the entire lander in full motion from the side or above. The images that this camera captures would be used for several purposes, primarily to provide data about the location and extent of rocket fuel impingement on the surface, and lunar dust and debris disturbance due to the landing. Other purposes include remote images of the landing sequence to help to determine spacecraft health, and to identify possible hazards in the landing area for the rover. Furthermore, images of the landing could promote the mission to the public.

The imaging systems should be designed to last through the lunar night using a combination of insulation and heating elements. This will provide the option of continuing operations and data collection for several additional weeks, months, or years past the first daylight period.

For reference, the Clementine ultraviolet/visible camera: CCD visible-wavelength camera.

Rover Subystem

A lunar rover subsystem would have three main objectives: mission experiments, technology experiments, and science experiments.

Mission

The rover should be fitted with a small robotic arm, or other sample collection device, to function as the primary method of supplying lunar samples to the oxygen plant. Regolith will be the primary material gathered by the collection device, but it should also be able to deliver small rocks (possibly up to 1kg) to the lander. The rover should be able to collect samples from non-contaminated soil outside the range of effect of the landers rockets. In addition, the rover should be able to collect multiple samples from different areas on the lunar surface, to allow for several different oxygen production tests. A backup robot arm would probably be a wise addition for the lander in case of a rover failure. Whatever the choice of rover sampling device, it must be able to interface properly with the oxygen plant to deliver its sample.

Other mission experiments would include use of the rover camera as a backup, and periodic imaging of the lander to check spacecraft health, or identify possible damage areas. Even more importantly, a rover experiment would add a great deal of positive P.R. to the mission. Due to the relatively short communication delay times to the Moon, the rover could be controlled in a semi-real-time mode (2-5 second delay) from Earth. This would bring a degree of interactivity to the mission that a rotating lander-camera would not.

Mission summary

Technology

The list of technology tests is quite extensive, but is designed to be completed within a 1-2 week span (at a short distance from the lander). These tests could be completed during the first lunar day (at least two weeks depending on landing site) and would prove of great interest to telerobotics experts, and future lunar design teams:

Technology Summary

Science

The main science experiment would be deployment and use of a rover-carried Alpha Proton X-Ray Spectrometer (APXS). This powerful imaging tool would be used to determine the composition of lunar rocks and soil by taking extended close-up scans. Additional soil and rock tests would be done by the rover vehicle itself. To reduce mission cost, complexity, or power requirements, the APXS could be removed from the rover.

Science Summary

The rover should be designed to last through the lunar night using a combination of insulation and heating elements. This will provide the option of continuing operations and data collection for several additional weeks, months, or years past the first daylight period.

For reference, the Rocky 4 rover designed for the 1997 Mars Pathfinder Mission

Penetrator Subsystem

A subsystem will be designed to search for subsurface water at two or more sites remote from each other (landing site may be included). The method is completely open, but must remain secondary to the oxygen demonstration mission. In addition to the search for water, a penetrator system offers a good opportunity to act as a technology test. Some criteria that should be considered are:

Other Sensor Systems

The navigation sensors will be researched and designed by the Guidance, Navigation, and Control group. However, after these sensors have fulfilled their guidance objectives, they should be considered for use in providing scientific data or achieving other mission objectives. For example, the star trackers could be used in a limited way as back-up cameras. The information below is provided for reference only as an example of typical navigation sensors.

Navigation Systems (Star trackers, Lunar Ranging Device)

The star trackers are used for determining the position and attitude of the vehicle before it reaches the lunar surface. Star trackers are fixed navigational instruments, but the design should include the option of transmitting their imagery to Earth.

For reference, the Clementine star trackers: CCD cameras used to image background stars.

The lunar ranging device will perform altimetry and mapping. Its main function is to detect possible obstructions and large slopes at the landing site. This system may use, but is not constrained to, a laser imaging system. Two advantages of LIDAR over RADAR are its small size and low power requirements. The LIDAR requires a laser emitter, but the receiver can be integrated into the UV/Visible camera listed above. After lunar insertion, but before landing, the ranging device can be used to map swaths of the Moon's surface. During the landing sequence, the lunar ranging device must ensure that safe (to be defined) terrain exists under the lander as it makes its descent to the surface.

For reference, the Clementine laser emitter (the receiver is in UV/Vis. camera): transmits laser pulses to the surface. The ship's computer uses pulse return time to determine the distance between the vehicle and the surface.

Additional Sensors

If the primary mission is within mass, power, and cost margins, the design should consider sensors for characterizing the lunar environment and its affects on the vehicle. Auxiliary sensors should focus on possible anomalous events recorded by previous missions. Instruments might characterize the vehicle's temperature gradient and the incidence of suspended dust particles.

For reference, the Galileo dust detector measures particle mass, velocity, and charge state.

Sensor Interfaces

Input group	Information/Interface	Output Group
NGC	Identify Instrument Positions / Fields of View
	Define Sensor Pointing Requirements	NGC
	Visible Imagery Specs for Landing Instrument Backup (Altimeter / Startrackers)	NGC
Structures	Identify Viewing Obstructions
	Component Mass/Volume	Structures
	Components Survivable Loading	Structures
	Positioning requirements	Structures
Propulsion	Exhaust plume Impingement
Thermal	Other Subsystem Thermal Interference
	Component Thermal Requirements	Thermal
	Thermal Energy Dissipation	Thermal
Computer	Instrument Scheduling
Computer	Instrument Pointing Control
Computer	Rover and Camera Control
	Sensor Data	Computer
Communication	Computer Bypass for Sensors to Communications for Uplink and Downlink	Communications
Communication	Realtime Rover Guidance from Earth
	Camera Requirements for Sample Identification and Experiment Monitoring	O2
Power	Instrument Scheduling Constraints/Requirements	Power
Power	PV array position (obstruction)
	Instrument Power Requirements	Power

Sensor References

Smith, Solar, "Ulysses" The University of Texas at Austin (Fall 1991).

Soyka, Mark T., "Sensor Description for the Clementine/DSPSE Mission" The University of Texas at Austin (21 February 1993).

Surveyor Project Final Report, Part I & II, Jet Propulsion Laboratory Technical Report 32-1265 (Pasadena, CA:1969).

"TOW Anti-Tank Missile (BGM-71)," in Janes Weapon Systems, 19th edition, ed. by Bernard Blake, Janes Information Group Inc. (Alexandria, VA:1988), p. 155-156.

Lunar Base

Campbell, Paul D., "First Lunar Outpost Surface Habitation Phase Crew Time Analysis," NASA Contractor Report LESC-30401, (1992). MS Word (50k); ASCII (38k)
Subjects: First Lunar Outpost (FLO)

Mendell, Wendell, "Lunar Base as a Precursor to Mars Exploration and Settlement," (1991). MS Word (40k); ASCII (35k) Subjects: Lunar Bases, Manned Mars Missions

Mendell, Wendell, "Lunar Base - Why ask, "Why?"?," AIAA Conference Paper, (1993). MS Word (30k); ASCII (23k)

ISRU Allen, Carlton C., Gary G. Bond, and David S. McKay, "Lunar Oxygen Production - A Maturing Technology," Proceedings of Space 94 (Engineering, Construction, and Operations in Space IV; American Society of Civil Engineers), (1994). MS Word (416k); ASCII (20k)
Subjects: ISRU, Materials

Allen, Carlton C., John C. Graf, and David S. McKay, "Sintering Bricks on the Moon,"Proceedings of Space 94 (Engineering, Construction, and Operations in Space IV; American Society of Civil Engineers), (1994). MS Word (336k); ASCII (20k)
Subjects: ISRU, Materials

Joosten, B. Kent, and Lisa A. Guerra, "Enabling Lunar Exploration through Early Resource Utilization," Paper presented at Space '94 Conference, (1994). MS Word (1,108k); ASCII(30k)
Subjects: LUNOX Mission, Lunar Resources, Extraterrestrial Resources

Joosten, B. Kent, and Lisa A. Guerra, "Early Lunar Resource Utilization: A Key to Human Exploration," Conference Paper AIAA Paper 93-4784, (1993). MS Word (148k); ASCII(50k)
Subjects: LUNOX Mission, Lunar Resources, Extraterrestrial Resources

McKay, David S, James L. Carter, Walter Boles, Carlton C. Allen, and Judith H. Allton, "JSC-1, A New Lunar Soil Simulant," Proceedings of Space 94 (Engineering, Construction, and Operations in Space IV; American Society of Civil Engineers), (1994). MS Word (412k); ASCII(20k)
Subjects: ISRU, Materials

Lunar Astronomy

Mendell, Wendell, "An International Lunar Lunar Farside Observatory and Science Station: (From the 1991 International Space University (ISU) Design Project," (1993). MS Word (240k); ASCII (55k)
Subjects: Lunar Far Side, Lunar Observatories

Mendell, Wendell, "An SEI Proposal: A Lunar Telescope for Education," (1991). MS Word(63k);ASCII(55k)
Subjects: Space Exploration Intitiative (SEI), Lunar Observatories, Telescopes, education

Policy and Strategy Mendell, Wendell, and Steve Hoffman, "Strategic Considerations for Cislunar Space Infrastructure," (1991). MS Word (43k); ASCII (38k)
Subjects: Cislunar Space, Infrastructures

Platoff, Anne, "Where No Flag Has Gone Before: Political and Technical Aspects of Placing a Flag on the Moon," NASA Contractor Report 188251, (1993). MS Word (2,668k); ASCII (33k) Subjects: Lunar Flags

References on the WWW:

Instrumentation Branch - Goddard Space Flight Center

JPL Center for Space Microelectronics Technology - Sensor Technology

Malin Space Science Systems

The Moon

NASA Space Sensors and Instrument Technology

Space Environmental Effects Branch - Lewis Research Center

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