To Mars: Assured Communication With Mars (MARSSAT)
Copyright © 2004 by Marilyn Dudley-Rowley
and Thomas Gangale
|
|
To Mars: Assured Communication With Mars (MARSSAT)Copyright © 2004 by Marilyn Dudley-Rowley
|
|
|
OPS-Alaska Expanding the Human Ecology Extreme Environments Research for Oceanic, Polar, and Space Applications Expert Information Submitted by: Dr. Marilyn Dudley-Rowley, Founding Researcher and Thomas Gangale, Executive Director 2262 Magnolia Avenue Petaluma, California 94952 USA V-Mail & FAX: 707-773-1037; Mobile: 707-494-0666; md-r@ops-alaska.com; www.ops-alaska.com Other professional affiliations of Dr. Dudley-Rowley’s are: American Institute of Aeronautics and Astronautics (AIAA)
Active List, NASA Astronaut Candidate Selection Files Professor, Sonoma State University Member, U.S. Department of Defense Human Factors Engineering Technical Advisory Group Collaborator-Partner, International Science and Technology Center (ISTC) Past Principal Investigator and Liaison, Russian Space Station Simulation, Institute for Biomedical Problems (IBMP), Moscow Other professional affiliations of Mr. Gangale’s are:
American Institute of Aeronautics and Astronautics (AIAA)
Technical Projects Manager of U.S. Department of Defense space shuttle payloads
Management Team Member
Co-Author of the USAF’s Space Systems Division Response to NASA’s 90-Day Study on the Space Exploration Initiative (SEI) Member, World Affairs Council of Northern California Member, United States Information Agency’s Alumni Association Fellow, British Interplanetary Society Member, Commonwealth Club Dr. Dudley-Rowley, Mr. Gangale, and OPS-Alaska are pleased to present: To Mars: Assured Communication With Mars (MARSSAT) Focus Area: Crosscutting Design Drivers and Architecture Elements THE THIRD OF THREE OPS-ALASKA RESPONSES TO THE NASA EXPLORATION SYSTEMS ENTERPRISE REQUEST FOR INFORMATION The Series of OPS-Alaska Responses Are: I. From the Earth to the Moon and Beyond: Transnationalizing Space Focus Area: Program Management, Acquisition, and Interfaces II. From LEO to the Moon and Beyond: Human Factors Safety Concerns of Space Stations and Other Human Environments Away From Earth Focus Area: Design Principles, Objectives, and Guidelines III. To Mars: Assured Communication With Mars (MARSSAT) Focus Area: Crosscutting Design Drivers and Architecture Elements ***** To Mars: Assured Communication With Mars (MARSSAT) Overview: The MARSSAT concept was developed by aerospace engineer and political scientist Thomas Gangale in the 1990s. Mr. Gangale designed a class of orbits to solve the problem of communicating with crews on Mars when the planet is in solar conjunction as seen from Earth, a planetary configuration that occurs near the midpoint of a conjunction class mission to Mars. This type of orbit minimizes the distance between Mars and the communications satellite, thus minimizing its size, weight, and power requirements, while providing a simultaneous line-of-sight to both Earth and Mars. Gangale’s orbits are solar orbits that have the same period as Mars, but are inclined a few degrees out of the plane of Mars' orbit and also differ in eccentricity from Mars' orbit. These differences cause a spacecraft in this orbit to rise north of Mars, then fall behind Mars, then drop south of Mars, and then pull ahead of Mars, by some desired distance in each case--typically about 20 million kilometers--in order to maintain an angular separation of a couple of degrees as seen from a point in Earth's orbit on the opposite side of the sun. A satellite in this type of orbit would relay communications between Earth and Mars during the period of several weeks when direct communication is blocked by the sun. These orbits are far superior for this purpose compared to stationing a satellite at one of the sun-Mars equilateral Lagrangian points, L4 or L5, for two reasons. First of all, L4 and L5 are 228 million kilometers from Mars, about 10 times the distance of a spacecraft in one of Gangale’s orbits, and by virtue of the inverse-square law, all other things being equal, the signal strength received at L4 or L5 would be 1/100 the signal strength received by a spacecraft in one of Gangale’s orbits. Thus, a relay satellite stationed at L4 or L5 would have to be that much more powerful to receive data at the same rate, with concomitant increases in spacecraft size and weight. Secondly, a number of Martian Trojan asteroids have been discovered at the sun-Mars L4 and L5 points, and there are probably countless smaller objects that have collected in these regions that would pose a significant threat to any spacecraft located there. Specifications follow as elaborated on in the following publication that typifies several similar publications and presentations to scientific and engineering groups throughout the 1990s till now. |