A Novel Concept for a Multiplanetary Crewed Mission to Mars and Ceres
For NASA, sending a crewed mission to Mars has been the long-term goal for over two decades. China has joined the club in recent years, with plans to send crewed missions to the red planet ahead of NASA. In both cases, the plans envision a stepping stone approach, using habitats and infrastructure in cis-lunar space to ensure that regular missions can be possible someday. They also envision how regular missions to Mars could lead to permanent habitats on the planet's surface.
In a paper submitted to the 56th Lunar & Planetary Science Conference (2025 LPSC), a team of engineers proposed taking these plans further. Their mission concept consists of a Human-Crewed Interplanetary Transport Architecture (HUCITAR) to explore Mars and Ceres (the largest body in the main asteroid belt) in a single journey. Through innovative planning and international cooperation, their ambitious plan envisions a 4-year, seven-month expedition with six astronauts that could be ready to launch by 2035.
Technical Specifications
Given the distances and transit times involved, the first technical priority is a propulsion system capable of generating sufficiently high acceleration (delta-v). Based on the different trajectories they studied and the different phases of the mission, the delta-v requirements range considerably. For instance, during the Mars transit portion of the mission, an optimal delta-v of approximately 6.1 km/s is required. However, to achieve the earliest Mars capture, the spacecraft must optimize its delta-v to ~3.75 km/s.
In one particular scenario, they calculate that a maximum delta-v of ~11.2 km/s is required. Overall, this architecture requires a maximum delta-v of around 5.59 km/s. While their analysis is largely based on conventional chemical propulsion systems, they indicate that a nuclear thermal propulsion (NTP) system would be more than sufficient. The feasibility of a mission departing by 2040–2050 is also explored based on technological readiness (particularly NTP), funding, and international cooperation.
In this paper, the authors do not address mitigation strategies for long-term exposure to radiation or microgravity, focusing instead on the technical requirements, propellant, and optimal trajectories to achieve a mission from Earth to Mars to Ceres.
Mission Overview
According to the research team, their multiplanetary mission architecture would consist of four phases. The first, Departure from Earth's LEO, would see six astronauts leaving low-earth orbit aboard the proposed spacecraft. They claim this departure could occur as early as July 2035, followed by a transit of between 192 and 258 days (6.5 to 8.5 months). The mission would reach Mars by March 2036, followed by a period of surface exploration.
This would be the mission's second phase (Mars Surface Exploration), during which three astronauts would descend to the surface using a reusable lander. A long-term habitat is needed for this phase to allow the astronauts to conduct science and exploration activities. Meanwhile, the remaining astronauts would depart for Ceres by April 2036, followed by a 574-day transit. Upon arrival by November 2037, the three-person crew would land on the surface.
This would be followed by phase three, Ceres Surface Exploration, which would last 46 days. By January 2038, the three astronauts would commence the return part of their journey to Mars. After another 574-day transit, they would rendezvous with the three-person team from the surface and begin the final phase, Earth Return. Departing by August 2039, the six-person crew would spend another 192-258 days returning to Earth, which would be complete by April 2040.
To address communication challenges, the team recommends deploying a Mars-Ceres Communication Relay Orbiter similar to the Mars Relay Network (MRN).
Possible Trajectories
The mission architecture explores three possible trajectories using NASA's Design and Integration Tool 42 (DIT-42), which simulates spacecraft attitude, orbit dynamics, and environmental models.
| Trajectory | Description | Estimated Duration |
|---|---|---|
| Direct Transfer | This mission profile is similar to the Mars Direct architecture proposed by Zubrin et al. in 1991. | ~945 days |
| Earth-Mars-Ceres Transfer | This trajectory involves a transfer approach with two burn phases. | ~833 days |
| Lambert's Trajectories | This scenario takes advantage of a favorable orbital alignment in 2035. | ~4.25 years |
Overall, the authors identified the Earth-Mars-Ceres Transfer Trajectory as the optimal one. As they state in their proposal paper:
"The chosen Earth-Mars-Ceres pathway mitigates the challenge of orbit capture with higher delta-v requirements, enabling the crew to depart with the least delta-v for safe and successful orbit capture at Ceres."
Looking ahead, the team intends to simulate advanced trajectories incorporating the exact positions of the planets along with precise departure and arrival dates. Mitigation strategies are sure to follow based on the evolution of the requisite technology—i.e., centrifuges, rotating sections, hibernation, and other proposed methods. In the meantime, their proposal provides an ambitious concept that could influence future studies and mission planning.
Conclusion
This ambitious concept represents a significant advance in planning human expansion into the solar system and highlights India's emerging role in conceptualizing advanced deep space missions. This architecture pushes the boundaries of current mission planning, combining pragmatic approaches with innovative solutions for multi-planet exploration.
More information can be found in the full paper: Conceptual Design of a Multiplanetary Mission Architecture for Human Exploration of Mars and Ceres.
