Melissa Doyle Surface Transportation: Lunar Science & Service Rovers University of Southern California ASTE 527: Space Exploration Architectures Concept

Melissa DoyleSurface Transportation:

Lunar Science & Service Rovers

University of Southern California

ASTE 527: Space Exploration Architectures Concept Synthesis Studio

December 15, 2008

Dec 15, 2008 Lunar Science & Service Rovers Melissa Doyle

Background

• “The Lunar Rover proved to be the reliable, safe and flexible lunar exploration vehicle we expected it to be. Without it, the major scientific discoveries of Apollo 15, 16, and 17 would not have been possible; and our current understanding of lunar evolution would not have been possible.”

– Harrison Schmitt, Apollo 171


Rationale• Mobility is key for rapid global exploration• The rovers of the future must be able to traverse farther than the

Apollo rovers.– Total Apollo 17 surface distance traversed = 35.9 km2

– Looking Glass 204 Observatory Project traverse estimate = 900 km (Mons Malapert, Shackleton, Schrodinger, and return to Mons Malapert in figure 8 traverse)

• New requirements imposed on lunar rovers of the future to perform new functions that the Apollo rovers never performed.

• Short Traverse requirements– Lander to Habitat distance of 3km

• Mars Forward– Systems development, verification, and validation in space and on the

lunar surface first – Closer to our home planet of Earth


Context - System Requirements• Lunar Rover mechanisms are expected to operate in the harsh lunar

environment: thermal cycling and radiation– -171 deg C to +134 deg C (-315 deg F to +273 deg F)

• Capable of operating in an induced environment– Lofted dust, g-forces, remain stable in pitch and roll

• Fully operational upon initial deployment• Capable to operate at any latitude or longitude• Capable of forward and reverse motion• Capable of braking• Capable of changing direction• Capable of supporting and transporting payloads• Capable of providing navigation information to the operator• Capable of communication with Lunar Base and/or Earth• Capable of recovering from a single failure and complete mission

– Failure modes at minimum Fail Operational/Fail Safe3


Objective

• To provide short and long traverse capability on the lunar surface in a safe and reliable manner for the crew.

• To aid in the establishment of a lunar base with vehicles equipped with tools for construction.

• To aid ISRU with vehicles equipped with tools.• To advance lunar science with the tools and

vehicles necessary to collect data samples and conduct experiments while in traverse.


Trade Studies

• Hoppers/Leapers– Not feasible for short traverses, nor large cargo transport– Requires rocket braking control system for landing at a particular site– Overlooks vast amount of lunar surface that could be utilized for

science experiments• Very Large Rovers

– May be difficult to actually get to the Moon– Single Point Failures

• Wagon Train Rovers– Not every vehicle needs to be “smart”, waste of resources4

• Tractor Train Rovers– Issue of fish tailing

• Twin Pressurized Rovers = Concept Architecture Down Select– Operated both manually and telerobotically


Assumptions• Traverse terrain is very rocky and rugged

– Large wheels required– Sufficient clearance of under carriage required– Average speed 10 km/hour– Mission from Mons Malapert to Schrodinger and back is

roughly 900 km, implies roughly 90 hours (3.75 Earth days) of traverse, not including stops

• Mission duration is 14 days to 1 month– Per STD 3000 NASA Spacecraft Standard, living space

required is 10 m3 per person for 1 month5

• Modular Design is necessary– For maintenance, remove and replace– For initial transport to the Moon


Concept Architecture

• Lunar Science & Service Rovers– “Science Car” - pressurized (x 1)

• Mobile habitat containing basic human consumables, sleeping quarters for crew of 4, plus complex science workstation for up to 2 crew members working at one time

– “Service Car” - pressurized (x 1)• Only the cabin is pressurized• Remaining chassis contains tool kit consisting of:

– Drill, Backhoe, Crane, Robotic Arms, Front End Loader, Winch, and Launcher

• Stowage Bin– Rocks and other samples collected in traverse– Payload capability greater than 4000 pounds (similar to Ford F-

250 truck)


System Schematic


Chassis & Crew Cabin


Science Car


Science Car


Science Lab - Internal


Living Quarters - Internal


Service Car


Service Car – Side View


Service Car – Front View


Service Car – Tool Kit


System Specifications

• Mass = 25 MT• Pressurized Volume

– Crew Cabin = 32 m3

• Command & Control Crew Cabin with airlock/EVA tools for suit don/doff• Ladder Required for egress/ingress due to under carriage clearance of 4 meters (13

feet)– Science Car = 60 m3

• Capable of mating up with the crew cabin by a joined airlock system

• Max Range = 6000 km• Power = Combination Solar and Fuel Cell• Navigation = Lunar “GPS” in Crew Cabin

– Lunar mapping collected from missions such as Chandrayaan-1 to be used for situational awareness6

– Cameras on front and back of rovers, data also used for science• Lighting

– Utilize Earth light • Less strain on rover systems

– Two Headlights on top of Crew Cabin• Shadows in low sun angle


Concept Advantages

• Dual string redundancy with 2 pressurized rovers– Not stranded with limited oxygen supply if one rover is not

repairable

• Modularity– Chassis and crew cabin are the same for both Science Car and

Service Car • Efficient Utilization of Resources

– Complexity driven out of design when not necessary

• Mars Forward– Potential application on a Mars mission


Risks / Disadvantages

• Design lacking emergency rescue abort– Entirely separate system from rovers could solve this

problem

• Traction of Service Vehicle for tool kit use– Certain areas of lunar surface may have very fine

regolith, wheels may slip preventing use of some tools completely (most likely launcher and drill)

– The anchors were added at the vehicle’s CG to address this problem, but it is still a viable risk


Conclusions

• 40+ years of lunar surface transportation and rover research

• Lunar Science & Service Rovers is the combination of the most plausible published concepts and “new” personal ingenuity

• This concept is capable of conducting traverses farther than Looking Glass 204 traverse of 1000 km– This project assumed traverse of roughly 1000 km in 4 days– 4 days * 6 = 28 days (almost one month, which is what Lunar

Science & Service Train was designed to, one month mission duration)

– So 1000 km * 6 = 6000 km MAX surface distance possible of traverse with Lunar Science & Service Rovers


Further Study

• Optimize power system• Motor selection• Application details of tools in the tool kit• Dust mitigation techniques• Detailed airlock design for egress/ingress• Detailed design of communication system• Optimize radiation shielding design


References

• (1) http://en.wikipedia.org/wiki/Lunar_rover and http://nssdc.gsfc.nasa.gov/planetary/lunar/apollo_lrv.html, accessed December 15, 2008

• (2), (5) The Lunar Base Handbook, Peter Eckart, pg 566• (3) AIAA 93-0996, Rover Concepts for Lunar Exploration, Connolly, J. F., February 1993• (4) AIAA 2003-6280, Mobile Lunar and Planetary Bases, Cohen, M. M., September 2003• (6) India’s Chandrayaan-1 http://www.aviationweek.com/aw/generic/story_channel.jsp?

channel=space&id=news/Indian092208.xml, accessed December 15, 2008• http://www.astronautix.com/craftfam/lunovers.htm, accessed December 1, 2008. • Cooper, B. L., Schrunk, D. G., Sharpe, B. L., Thangavelu, M. (2008). The Moon (pp. 251-255, 387).

Chichester, UK: Praxis.• http://www.nasa.gov/mission_pages/constellation/ares/aresV/index.html, accessed December 13, 2008• Wikipedia. (2008) Technology Readiness Level. Retrieved September 21, 2008, from

http://en.wikipedia.org/wiki/Technology_Readiness_Level• AIAA 93-0993, Considerations for the Design of Lunar Rover Structures and Mechanisms for

Prolonged Operations in the Lunar Environment, Rao, N. S., Wallace, B. E., February 1993• Artillery based explorers: A new architecture for regional planetary geology, Garrick-Bethell, Ian,

www.sciencedirect.com, June 13, 2005• AIAA 2003-5938, Fuel Cells for Space Science Applications, Burke, K. A., November 2003• John Dorsey’s Lunar Surface Manipulation System (LSMS),

http://www.nasa.gov/mission_pages/exploration/main/lsms_prt.htm, accessed December 15, 2008


Acronyms

ASTE Astronautical & Space Technology Engineering

CG Center of Gravity

EVA Extra-Vehicular Activities

ISRU In-Situ Resource Utilization

KM Kilometer

LSMS Lunar Surface Manipulation System

MAX Maximum

MT Metric Ton

STD Standard


BACK-UP SLIDES


Stowage Bin Capability

• The average rock samples returned from Apollo missions 15, 16, and 17 was roughly 100 kg (220 pounds) over an average of 25 km (15.5 miles). Since the Looking Glass 204 Project will be traversing 18 times farther in one direction (roughly 450 km total from Mons Malapert to Shackleton and then on to Schrödinger), it is assumed that the stowage area must be capable of holding 18 times more cargo. The stowage area is thus capable of hauling 1800 kg (roughly 4000 pounds). This is not an extraneous amount of cargo, as a Ford F-250 has a payload capacity of 6190 pounds.


John Dorsey’s Lunar Surface Manipulation System (LSMS)

• The test article is a full-scale device and, like the concept it represents, is sized for unloading a lunar lander. For unloading a lander or getting to high places, the arm and forearm would be rotated up 45 degrees and extend as high as about 9 meters (30 ft.) above the surface. When reach is more important, it can be configured as a

horizontal boom, 3.75 meters (12 ft) tall and stretch out 7.5 meters (25 ft). • In addition to heavy-duty tasks, the LSMS is designed to handle "light" payloads --

those too large or massive to be handled by astronauts. These payloads range from 100 to 3,000 kg (220 to 6,600 lbs) and include things such as communications or power equipment, and even lunar rovers.

Documents

Melissa Doyle Surface Transportation: Lunar Science & Service Rovers University of Southern California ASTE 527: Space Exploration Architectures Concept