Brimley_2000

SPACECRAFT SYSTEMS DESIGN OF A MANNED MARS VEHICLE SYSTEM – AFOURTH YEAR STUDENT TEAM PROJECT USING THE INTERNET

W. Brimley, Ph.D., P. Eng. *

ABSTRACTSeven student teams at four Ontario universities (Queen's, Royal Military College, Ryerson andYork) were challenged to perform the preliminary system design for a manned spacecraftcapable of leaving earth and traveling to Mars. The crew is to land on the Martian surface,explore and then return to earth. This manned mission to Mars uses the optimum combination ofthe "Mars Direct" approach proposed by Robert Zubrin, and the NASA Reference Mission. Themanned mission would use departure from the International Space Station (ISS), with a directdescent to Mars using aerobraking and parachutes, or a transfer vehicle may be left in orbitaround Mars for the earth return.

The complete spacecraft system to be designed, including its Ground Control Segment, isnamed the MMVS (Manned Mars Vehicle System). Other components such as the propellantmanufacturing plant and the nuclear power plant were assumed to be available. However,complete mission planning including the precursor unmanned mission to place these componentson Mars was performed.

The results from the teams are summarized and compared. Student representatives willdiscuss their design and issues they found. This presentation focuses on the achievements ofstudents by demonstrating results from the team websites where the final reports are mounted.Benefits to our students such as participation in events such as this Mars Society Conference arenoted. Many former staff and student alumni are now employed in the space industry, or areenrolled in post-graduate programs in universities including the International Space University.

The Interactive Learning Connection - University Space Network (ILC-USN) is aconsortium of North American Universities, Centres of Excellence, and Industry that hassuccessfully established an Internet based course in "Spacecraft Systems Design". Since the fallof 1995, 255 undergraduate and 13 graduate students have completed this course at universitiesin the United States, Canada and Mexico.

1.0 PROJECT INTRODUCTION – MANNED MARS VEHICLE SYSTEM (MMVS)

Student Teams were challenged to design a manned spacecraft capable of leaving earthand traveling to Mars. The crew will land on the Martian surface, explore and then return toearth. The project will be a manned mission to Mars using the optimum combination of the"Mars Direct" approach proposed by Robert Zubrin, and the NASA Reference Mission.

* Operations Manager, Interactive Learning Connection - University Space Network,School of Aerospace Engineering, Ryerson Polytechnic University

Royal Military College (RMC) recommended a "Modified Mars Mission" That woulduse departure from the International Space Station (ISS), with a direct descent to Mars usingaerobraking and parachutes. The return trip would be to Low Earth Orbit (LEO).

The student Teams are required to calculate departure from earth orbit (i.e. the spacecraftvelocities and delta V's required) to travel to Mars and land on its surface. Then after a stay onMars to calculate the return to earth orbit. We can assume the (MMVS) spacecraft will beassembled in low earth orbit at the new International Space Station. Sizing of the vehicle will bedriven by the velocities, corresponding fuel mass calculations, for a given payload (e.g. crewcompartment, ascent vehicle, etc.).

1.1 Mission Statement The mission is to send a manned spacecraft to land on the planet Mars and after the crewexplores Mars to return the crew safely to Earth. The term project is to perform the preliminary system design of the manned spacecraft systemsand components capable of this mission. This complete spacecraft system to be designed,including its Ground Control Segment, is named MMVS (Manned Mars Vehicle System). Othercomponents such as the propellant manufacturing plant and the nuclear power plant will beassumed to be available. However, complete mission planning including the precursorunmanned mission is necessary.

1.2 Background

1.2.1 MARS Direct Plan (Zubrin) Note: the following is a combination of Zubrin's proposals. 1.Begins with the launch of an unmanned Earth Return Vehicle (ERV) that will land on Mars and manufacture propellant.2.Two years later another ERV and a Manned Spacecraft (MMVS) leave Earth for Mars. The MMVS lander lands next to the previous ERV and manufactured propellant. The second ERV may also land in close proximity to provide a backup return vehicle (or land within a 300km range from the initial ERV).3.The crew leaves Mars after one and one-half years, using the first ERV. A second manned mission and third ERV may land before they depart (more backup).4.The landings continue, leaving a string of landing sites (base camps) across the Martian surface.

1.2.2 NASA Reference Mission 1.An unmanned ERV is placed in orbit around Mars. It is fully fueled and capable of remaining on orbit for over four years.2.An unmanned cargo lander is launched and landed on Mars. It contains an unfueled

ascent vehicle, propellant production plant, nuclear power plant, and Habitat.3.A manned lander is launched and lands in close proximity to the cargo lander. The crew lives in the Habitat.4.The crew leaves after about 500 days using the ascent vehicle, performs a rendezvous with the ERV in orbit around Mars and returns to Earth.

1.3 Assumptions

The mission concept is based upon those of Zubrin and the more conservative NASAReference Mission (see reference articles). However we are allowing for two major differences:1.Assembly of the vehicle in LEO (i.e. at the ISS) The MMVS spacecraft is launched from the International Space Station (ISS), whose orbit is assumed to be circular. The Orbit of the earth is assumed circular, and the orbits of the ISS, earth, and Mars are co- planar.

2.The MMVS may perform a direct descent to Mars surface, or a transfer vehicle may be left in orbit around Mars for the earth return. The choice will be up to each design Team.

2.0 MMVS OPERATIONS CONCEPT

The MMVS must be designed for assembly in low earth orbit at the International SpaceStation (ISS), using existing technology. The MMVS must safely carry a crew and necessary lifesupport for a round trip from the ISS to Mars

2.1 Mission Profile: 1. Launch MMVS components to the ISS using NTS Space Shuttle, and or expendable vehicles such as Russian Energia.2. Assemble MMVS at the ISS using Canada's SRMS (Shuttle Remote Manipulator System, SSRMS (Space Station Remote Manipulator System), and SPDM (Special Purpose Dexterous Robot).3. Check out and Test MMVS at the ISS.4. MMVS unberths from ISS and departs for Mars when assured propellant stock has been manufactured by previous Cargo landing.5. MMVS executes trajectory burns and maneuvers to enter Mars orbit or performs a direct descent.6. Landing on Mars at predetermined landing site which provides a propellant manufacturing facility with previously manufactured propellant, and nuclear power plant (and Habitat an option).7. Explore Mars and obtain propellant from site storage8. Depart Mars9. Rendezvous if necessary with Earth return vehicle.10. MMVS executes trajectory burns and maneuvers to rendezvous with the ISS.11. Berthing of MMVS to ISS

2.2 Additional MMVS Functions: Remote Control; Ground Operated (Option/Back-up) MMVS Command and Control Telefunction Human-in-the-Loop Automatic Control Robotics Cargo and propellant manipulation (loading/off-loading) Vehicle berthing/deberthing Transportation Transport crew and/or cargo into space (sub-orbital or earth orbit) Return of crew and cargo Life Support

Provide life support for IVA and EVA crew.

3.0 TEAM DESIGNS

Table 3.1 Comparison of Some Student Team Designs against ISS

TEAMQUEEN'S #1 QUEEN'S #2 QUEEN'S #3 RMC RYERSON ISS

UNFUELLED 82,574 21,600 111,150 27,341 216,974 ~ 455,000MASS (UFM)FUEL+ Tanks 483,575 2,472,920 14,915,110 738,743 1,030,000MASS (FM)

TOTAL 566,149 2,494,520 15,026,260 766,084 1,246,974 455,865MASS (TM)

FM 85% 99% 99% 96% 83% < 0.2%TM

LENGTH Length=79.9(m) Width=108.6

ENGINES Chemical Chemical Chemical Chemical Nuclear RCS/ReBoostRocket Rocket Rocket Rocket Thermal

RocketCREW 3 4 8 4 3 7

ELECTRICAL Solar Cells + Solar Cells + Solar Cells + RTGs NTR Cooling Solar CellsPOWER Fuel Cells RTGs Fuel Cells Turbines

LAUNCHERS Space Shuttle Space Shuttle Zenit Space Shuttle Space Shuttle Space ShuttleAriane V Titan IV Vostok Titan IV ProtonProton Energia Energia Soyuz

Proton ProtonNO. OF 21 163 67 14 29 > 45

LAUNCHES

Notes:1 Mass in kg2 Data taken from assignments and may be refined in Final Reports3 Space Station Data Oct/98 (FM estimated)

3.1 TEAM YORK http://www.yucc.yorku.ca/~ravi/mars/

3.2 TEAM RYERSON http://www.geocities.com/CapeCanaveral/Galaxy/7191/

3.3 TEAM QUEEN’S #1 http://lucy.me.queensu.ca/~usn99q1/

3.4 TEAM QUEEN’S #2 http://lucy.me.queensu.ca/~usn99q2/

3.5 TEAM QUEEN’S #4 http://lucy.me.queensu.ca/~usn99q4/

3.6 TEAM RMC http://www.rmc.ca/special/projects/mars 4.0 REFERENCES

Zubrin and the Mars Society: USA: http://www.marssociety.org Canada: http://canada.marssociety.org NASA: http://www.hq.nasa.gov/osf/hotlist/index.html http://members.aol.com/dsportree/exlinks.htm http://cmex-www.arc.nasa.govBooks: "Islands in the Sky" by S. Schmidt and R Zubrin, Wiley Popular Science, 1996, ISBN 0-471-13561-5 “The Case for Mars” by R. Zubrin with R. Wagner, Simon & Schuster, 1996, ISBN 0-684-82757-3 A magazine article: "The Future of Space Exploration", Scientific American (May 1999) whichcontains a few articles including Sending Humans to Mars by Robert Zubrin.http://www.sciam.com/specialissues/0399space/0399quicksummary.html A magazine article: Popular Science, February 1999 "Manned Mission to Mars". A magazine article: Newsweek, July 25, 1994 "Next Stop Mars".