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This paper will provide an overview of current options and specific concepts for a potential Mars Sample Return (MSR) architecture being jointly studied by NASA and ESA. Overall objectives and mission options will be described, including the architecture's constraints and notional timelines. The paper will highlight architecture-level trade studies, including specific elements and their status. The overall Sample Retrieval Lander (SRL) mission concept, including vehicle options will be described, including the Mars Ascent Vehicle (MAV), Sample Fetch Rover (being studied by ESA), Orbiting Sample container (OS), and tube transfer robotics systems. The concept and status of the Earth Return Orbiter (ERO) mission, being studied by ESA, and the Capture/Containment and Return System (CCRS) which would be the payload on the ERO, will be discussed. The information provided about possible Mars sample return architectures and concepts is for planning and discussion purposes only. NASA and ESA have made no official decisions to implement Mars Sample Return. • -Campaign objectives. • -Campaign-level description of MSR. • -Phases of mission concept of operations. • -Definition of reference baseline. [ABSTRACT FROM AUTHOR]

After launching from the martian surface via the Mars Ascent Vehicle (MAV), the MAV and the Orbiting Sample (OS) capsule containing the samples collected on Mars by the Perseverance rover are to be identified by the Narrow Angle Camera (NAC) on the Earth Return Orbiter (ERO) spacecraft in order to determine the exact orbit of the capsule before rendezvous. To ensure detection of the OS, noise and straylight contributions to the NAC must be well characterized. Here, we assess the radiometric environment at Mars likely to be encountered by the NAC—from the surface through the middle atmosphere—using the High Resolution Stereo Camera (HRSC) onboard Mars Express (MEx) and the Mars Climate Sounder (MCS) onboard the Mars Reconnaissance Orbiter (MRO). The results show that the radiance values in general tend to increase as phase angle increases, as the season progresses from L s = 60° to L s = 230°, and as altitude decreases. We compare HRSC and MCS profiles where observing conditions were similar and find good agreement. At specific latitudes, high-altitude aerosols are present in 1–5% of observations and significantly increase the worst-case radiance contribution above 50 km. We construct envelope profiles from the maximum radiances at 5 km intervals from 0 to 90 km that provide important input for straylight calculations of the NAC and for the validation of models that may be used as input for straylight calculations. [ABSTRACT FROM AUTHOR]

Abstract: This paper introduces new concepts of on-orbit propellant depots for human space exploration based on contingency propellant. The proposed architecture is useful in that it does not require separate depot filling missions, whereas conventional depot architectures require large “prior investment” type missions for depot filling before gaining the returns. Two concepts for this type of depots are shown: “steady-state” architecture and “stockpiling” architecture. In the “steady-state” mode, the depot always keeps the contingency propellant in orbit as well as the reused habitat module. In each mission, the vehicles collect the habitat and the contingency propellant from the depot in orbit on its way to the destination, perform the maintenance for the habitat, and leave the habitat and the unused contingency propellant in orbit on its way back. In the “stockpiling” mode, on the other hand, the habitat module is reused in the same way, but the depot accumulates propellant so that a later mega-mission can carry larger payload. Numerical results show the usefulness of the proposed architectures. [Copyright &y& Elsevier]

Abstract The current aim of NASA's Journey to Mars is a stepwise approach towards landing humans on the Red Planet, culminating in a sustained presence. There are many recent studies on how this could be achieved in an evolvable and affordable manner. Most architectures begin with crewed missions to Phobos or Mars orbit in the mid-2030's, progress toward short-stay missions on the surface, and then culminate with regular, long-stay missions at a permanent outpost in the 2040's. A common factor of these architectures is that many robotic launches would be required in order to support the crew by prepositioning mission elements and other needed supplies. In this paper, the use of 150 kW reusable Solar Electric Propulsion (SEP) tugs as a means to deliver elements both to orbit and the surface is studied. The conceptual SEP tugs make use of continued technology developments that were initialized through the Asteroid Redirect Robotic Mission (ARRM). They would also be used to deliver food and supplies to sustain the crews similar to resupply missions for the International Space Station. These SEP tugs would cycle (with loitering) between staging orbits in cislunar space and Mars orbit. The concepts presented here focus on the use of SEP for purposes of delivering cargo, and could potentially be complimentary to many human Mars architectures presented in the literature. In order to characterize mission design parameters such as dates, masses, and durations, thousands of optimized trajectories were run using low-thrust optimization software. Solutions are found for all launch/arrival date pairs for the years 2038–2053. They can be displayed as contour plots called Bacon plots – the SEP equivalent of porkchop plots. Possible mission architecture concepts for a steady-state human presence on Mars along with the cargo missions needed to keep it functioning are described and the relevant mission parameters such as launch dates, masses, arrival dates, etc., are given. It was found that the reusable SEP tug architecture would be highly beneficial to the logistics of a sustainable Mars outpost. Highlights • Solar Electric Propulsion offers an efficient method to transfer cargo to Mars. • Reusable SEP tugs stationed at the Lunar gateway offer flexible trajectories. • ARRM project SEP technologies can be levied for use in human mission architectures. • Optimal SEP tugs would require 100–200 kW of power to provide sufficient acceleration. [ABSTRACT FROM AUTHOR]