Concept of Operations for Future Mars Helicopters: Accessing Distant Targets with a Pathfinder-Style EDL System

. IntroductionThe highly successful campaign of the Ingenuity Mars helicopter [1] proved the feasibility of powered, controlled flight on Mars and has motivated the development of next-generation Mars helicopters as an option for future missions. Two design classes have been considered: a coaxial Advanced Mars Helicopter (AMH) [2], which would be approximately the same size as Ingenuity but with the ability to carry a ~1.3 kg science payload; and a larger Mars Science Helicopter (MSH) [3] designed to carry a science payload of ~2-5 kg.An aerial platform would provide greater range and access to scientific targets than traditional landers and rovers [4-5]. Science investigations enabled by MSH are wide-ranging and encompass the high-level science goals identified by the Mars Exploration Program Analysis Group (MEPAG) [6]. Trades exist between pairing MSH with other landed assets or as a standalone science mission. A dedicated MSH payload would reduce upmass and mission cost and would allow a wider range of heritage entry, descent, and landing (EDL) systems to be considered. We explore concept of operations (CONOPS) for an Ingenuity-sized AMH delivered to the surface of Mars using a Pathfinder-style EDL system.2. Landing Constraints from Heritage EDL SystemsA vehicle packaging study was conducted as part of a broader assessment of the AMH design. Compared to the Viking and MSL/Mars 2020 aeroshells, the Mars Pathfinder aeroshell is both the smallest and least expensive [2]. The baseline AMH design can be packaged within Pathfinder&#8217;s tetrahedral petal lander in an upright position with rotor blades folded downward [2]. The Pathfinder and later Mars Exploration Rover (MER) EDL systems had largely similar designs [7-8]. The ~70x200 km ellipse for Pathfinder [9] was made narrower for MER at ~12x80 km [10]. We use the slightly more lenient Pathfinder altitude constraint of < 0 km with the improved MER ellipse dimensions in our CONOPS.We explored areas of Mars that met these general criteria and identified Hadriacus Palus, a flat region to the northeast of Terby crater in the Hellas basin, as our study site. Terby contains a ~2 km-thick sequence of layered sedimentary rocks on its northern wall [11-12] and was a candidate landing site for the Curiosity rover [13]. Hadriacus Palus was a candidate landing site for the Perseverance rover [14], and it also contains exposed stratigraphy on its floor and in nearby Hadriacus Cavi [15-16]. Aerial investigations of the Terby&#8211;Hadriacus layered deposits would enable stratigraphic and mineralogic mapping of different sites where the deposits are exposed over a significant vertical distance. The landing ellipse and CONOPS we describe below are for demonstration purposes only, and they may not meet all engineering or safety requirements for landing site selection.3. Concept of Operations for Reaching an Initial Science TargetWe propose a standalone MSH architecture that would involve an initial commissioning phase in which the objective is to quickly and safely cover the distance between the landing site and the initial science target. The MSH concept study uses a design mission profile consisting of an initial 30 second hover, a 1 km flight, and a 2 minute hover before landing and recharging for 1 sol [3]. Reducing the pre-landing hover to 30 seconds increases the range to ~4.5 km [2-3].Figure 1 shows a notional MER-sized landing ellipse in Hadriacus Palus. With a series of 1 km flights, AMH could reach Terby in ~164 sols; with longer 4.5 km flights and reduced hover time, the distance could be covered in ~36 sols. It would take ~15 sols to reach Hadriacus Cavi with 1 km flights and ~3 sols with 4.5 km flights. There is a clear advantage to minimizing hover time for our proposed CONOPS, as it allows AMH to cover the same distance in a fraction of the time and equates to less risk of flight anomalies en route.4. MSH as a Low-Cost Mission ArchitectureMSH represents an opportunity to adopt the high-risk, high-reward posture of NASA&#8217;s commercial lunar exploration program with the potential benefit of highly focused, low-cost science missions to Mars. Adjusting for inflation, Mars Pathfinder cost ~$541 million, while the Curiosity and Perseverance missions have cost more than $2 billion each [17]. For comparison, current CLPS contracts range from ~$70&#8211;300 million [18]. While direct comparisons of these costs ignore many of the differences in mission development, launch, and operations, it is clear that a Pathfinder-style mission can be achieved at a fraction of the cost of the current generation of flagship Mars missions and at only a slightly higher cost than current CLPS contracts. Individual missions could then be competed by soliciting proposals for science targets or payloads that employ a common MSH architecture.Fig. 1. Map of landing ellipse and nominal MSH flight paths to reach science targets in Hadriacus Palus. Dashed lines mark 10 km increments with sols required to traverse with 1 km (yellow/red) vs. 4.5 km (cyan/green) flight segments. Center of landing ellipse is ~26.97&#730;S, 77.45&#730;E with MOLA elevation &#8211;2664 m.References[1] Balaram J. et al. (2021) Space Science Reviews 217 [2] Withrow-Maser S. et al. (2020) AIAA ASCEND [3] Johnson W. et al. (2020) NASA/TM&#8212;2020&#8211;220485 [4] Balaram J. et al. (2019) 9th Intl. Conf. on Mars [5] Bapst J. et al. (2021) AAS Bulletin 53 [6] MEPAG Science Goals Document (2020) [7] Golombek M.P. (1997) JGR 102 [8] Crisp J. A. et al. (2003) JGR 108 [9] Golombek M.P. et al. (1997) JGR 102 [10] Golombek M.P. et al. (2003) JGR 108 [11] Wilson S. A. et al. (2007) JGR 112 [12] Ansan V. et al. (2011) Icarus 211 [13] Wilson S. et al. (2007) Second MSL Landing Site Workshop [14] Skinner J.A., Jr. et al. (2015) Second Mars 2020 Landing Site Workshop [15] Skinner J.A., Jr. et al. (2017) LPSC 48 [16] Skinner J.A., Jr. et al. (2021) Icarus 354 [17] Planetary Exploration Budget Dataset, The Planetary Society [18] Commercial Lunar Payload Services, https://govtribe.com/award/federal-vehicle/commercial-lunar-payload-services-clps