# From the Martian Surface to Its Low Orbit in a Reusable Single-Stage Vehicle--[PERSON]
## 1 Introduction  
At the current time, with multiple space agencies planning for future Mars exploration missions, it seems like humanity will be arriving on the red planet sooner rather than later. The likely step after first arriving on Mars will be to establish a permanent human presence on the planet by setting up a colony. However, a continuous supply of humans and materials is needed in order to build, maintain and grow such a colony.  
A sustainable and reusable transportation method between Earth and Mars must thus be available. This will likely require spaceships to be constructed in Earth orbit, without landing capability. The sheer amount of cargo and personnel required to be transferred means that a single launch from Earth would be prohibitively expensive. To increase the flexibility of exploration and allow for large transfer ships, a reusable vehicle that functions as a shuttle service between Low Mars Orbit and the Martian colony could provide a reliable link for the resupply and transfer of people to and from the surface.  
Preliminary designs for such a vehicle already exist. NASA (US) has come up with a single-stage reusable vehicle that could be operated on both the lunar and Martiansurfaces, with separate configurations [1]. Lockheed Martin (US) came up with a design concept as well, with the Mars Ascent/Descent Vehicle (MADV) [2]. Both of these mission concepts focused on the design of the transport vehicle itself. This article similarly describes a new design of a reusable Single-Stage-To-Orbit (SSTO) launcher operating between a Mars base and a spacecraft in Low Mars Orbit, with safety at the core of its design. This vehicle has been code-named Charon. Furthermore, the constraints the design would put on the base are analysed. This way, a more complete analysis can be performed on whether the vehicle design is realistically feasible or not.  
This transportation method would have to adhere to certain key requirements. Among the 80 requirements that have been defined for this mission, the most important were the following three. First, the design shall be capable of transporting a payload of six humans and 1200 kg of cargo. Secondly, for the design to be sustainable, any parts that are not designed to survive the entire operational lifespan of the vehicle, and any consumables used during its nominal mission, shall be producible on Mars through in-situ resource utilisation (ISRU). Finally, since the vehicle will be used to transfer humans, it shall have a SL-LOC probability of 0.5%. This number has been based on the Crew Dragon Loss of Crew probability of 1 in 270 [3].  
In this article, first a mission profile is created, which describes how the vehicle reaches Low Mars Orbit, docks to the orbiting vehicle, and lands again. This is followed by a preliminary technical design of the vehicle and its subsystems, while adhering to the key mission requirements and focusing on reliability and maintainability. With the vehicle designed, the budgets for mass, velocity, and cost are calculated, and a failure analysis is performed. Finally, a conclusion is made on the feasibility of the design, in the case that the vehicle would be operational at the start of 2040. This is done by looking at the requirements it imposes on the Mars colony, such as the amount of fuel the colony would need to produce or the infrastructure required to service the vehicle.