Mars Communications Relay

NASA's major Mars science orbiters all carry a high-speed UHF relay, but their low mapping orbits mean that other missions are rarely within line-of-sight to relay their data back to Earth. However, even organizations such as AMSAT have launched UHF repeater satellites with enough capability to provide this missing link, which have massed 15 kg or less. These spacecraft can also provide a GPS-like system for locating balloons and rovers, or providing real-time positioning during final approach of landing for surface missions.

The proposal is to send several small relays instead of carrying yet another radio on the upcoming Canadian Mars mission. With a payback on the first flight, this will be less expensive than an X-band radio and a large, self-unfolding, steerable dish. Once launched, Mars spacecraft need to carry only a small, cheap, low-powered radio instead of one capable of transmitting hundreds of millions of kilometers.

Download the PDF entitled 'Reducing Cost and Complexity of Future Missions to Mars with a Microsatellite Constellation Providing a Shared Communications and GPS Service'. Presented at the Canadian Space Exploration Workshop 4 in Ottawa, hosted by the Canadian Space Agency.

Reusable Tether Transfer Stage

This proposal dramatically reduces the launch costs for interplanetary missions, using a reusable in-space satellite transfer stage, which reboosts itself without using propellant using electrodynamic propulsion. More precisely, it is a momentum exchange tether.

A Dnepr launch puts 4,500 kg into orbit, containing two Delta-class Mars missions and the tether facility. Break-even is on the first payload, as two missions are delivered to Mars for less than the cost of one Soyuz-Fregat (the least costly competitor to the heavy-lift Delta II).

Thereafter, the facility can continue to transfer payloads of 650 kg from a low orbit directly into Low Lunar Orbit, or into L4 for a 500 m/s transfer to Mars. It delivers 300 kg directly to a Mars re-entry, or places 1,500 kg from low orbit into GTO, all without consuming any propellant.

Download the PDF entitled 'Dramatically Reduced Launch Costs for Mars Missions using a Reusable Momentum Exchange Tether with Electrodynamic Reboost as the Upper Stage'. Presented at the Canadian Space Exploration Workshop 4 in Ottawa, hosted by the Canadian Space Agency.