Earth Departure Stage Technology Requirements for the Mars DRM

摘要

Mars Design Reference Architecture 5.0 (Mars DRA5.0), released in 2009, presented a method for sustained human exploration of Mars using either Nuclear-Thermal Propulsion or Chemical Propulsion along with a Heavy-Lift Launch Vehicle such as the Ares V. The reference heavy-lift launch vehicle for the lunar architecture program of record and several alternatives were assessed during Mars DRA5.0. Currently, the Ares V vehicle concept envisioned for use in the lunar architecture consists of two 5-segment reusable Solid Rocket Boosters, a Core Stage (CS) with five RS-68B-E/O engines, an Earth Departure Stage (EDS) powered by one J-2X engine and a Payload Shroud. Extensibility options for this vehicle concept were assessed which included the Mars mission scenario. An updated assessment of the Ares V vehicle concept as it pertains to Mars missions utilized the general architecture as defined in Mars DRA5.0. This architecture consists of two cargo Mars Transfer Vehicles (MTVs) that are pre-deployed and utilize aerocapture for Mars Orbit Insertion (MOI) before a Crewed MTV departs on the following synodic opportunity utilizing propulsive capture for MOI. An option assessed by the Ares V team during the latest analysis cycle which proved to be attractive from multiple perspectives was the utilization of the Ares V EDS as a dual-use stage providing functionality as both an ascent stage element and as the in-space transportation element for the architecture. This option is termed the EDS as MTV option, or commonly referred to as the Scavenger Option. Assumptions relative to the technology development requirements were made in Mars DRA5.0 and most follow-on activities. These include, but are not limited to, zero-boiloff (ZBO) technologies and/or more capable passive and active thermal control systems, improved automated rendezvous and docking (AR&D) technology, significantly increased launch rates, increased loiter & impact exposure risk in LEO, and the ability to integrate with several payload types (i.e. multi-use payload shroud, transhab, chemical stages, etc.). A distinct technology assumed for the chemical options further assessed by the Ares V team is no-vent fill (zero mass loss) cryogenic propellant transfer. These required technology developments will be discussed in this paper. This will include a brief mention of the current state-of-the-art of the key developments specific to the Scavenger option and how this option provides a unique opportunity to decouple from multiple technology developments and even allows for a major commercial market to be integrated into the overall mission strategy.