Earth Return Vehicle Research Articles

IMARS Phase 2A Draft Mission Architecture and Science Management Plan for the Return of Samples from Mars Phase 2 Report of the International Mars Architecture for the Return of Samples (iMARS) Working Group.

iMARS Phase 2A Draft Mission Architecture and Science Management Plan for the Return of Samples from Mars Phase 2 Report of the International Mars Architecture for the Return of Samples (iMARS) Working Group.

Conceptual Design of a Small Earth Reentry Vehicle for Biological Sample Return

A conceptual design of an Earth return vehicle is presented with the goal of safely returning biological samples from orbit. Key entry, descent, and landing trade studies were completed at the conceptual level for two different mission scenarios: return from the International Space Station and an autonomous, free-flying vehicle returning from low Earth orbit. The analyses that follow for each key subsystem drove design decisions to create the Biopan Deployment in Orbit for Microgravity Exposure vehicle with the versatility to satisfy both of the aforementioned mission scenarios. The final design features a ballistic entry, a 45 deg sphere–cone aeroshell with a diameter of 88 cm, a phenolic impregnated carbon ablator heat shield with a thickness of 7.7 cm, and a passive landing system containing an 8-m-diam ringsail parachute combined with a 7.8-cm-thick crushable carbon foam. Analysis of the vehicle performance verified survivability of biological samples due to heat and deceleration loads from entry. Trajectory dispersion analysis yielded crossrange and downrange limited to and , respectively, whereas landing velocity was confirmed to be for all cases.

Robust, affordable, semi-direct Mars mission

A new architecture is proposed for the first manned Mars mission, based on current NASA developments (SLS and Orion), chemical propulsion for interplanetary transit, aerocapture for all vehicles, a split strategy, and a long stay on the surface. Two important choices make this architecture affordable and appropriate for the first mission. The first is splitting the Earth return vehicle into two parts that are launched separately and dock in Mars orbit. This is necessary to make aerocapture feasible and efficient, which considerably reduces mass. The second is reducing the crew to 3 astronauts. This simplifies the mission and reduces the SLS payload mass under the 45-metric ton limit for a direct TMI (trans-Mars injection) burn without LEO assembly. Only 4 SLS launches are required. The first takes the Mars ascent vehicle and in situ resource utilization systems to the planet’s surface. The second takes the first part of the Earth return vehicle, the habitat, into Mars orbit. Two years later, two further SLS launches take a dual-use habitat (outbound trip and surface), Orion, and an enhanced service module to LEO, and then into Mars orbit, followed by the landing of the habitat on the surface. Transit time is demonstrated to be easily reduced to less than 6 months, with relatively low impact on propellant mass and none at all on the architecture.

An efficient approach for Mars Sample Return using emerging commercial capabilities

Mars Sample Return is the highest priority science mission for the next decade as recommended by the 2011 Decadal Survey of Planetary Science (Squyres, 2011 [1]). This article presents the results of a feasibility study for a Mars Sample Return mission that efficiently uses emerging commercial capabilities expected to be available in the near future. The motivation of our study was the recognition that emerging commercial capabilities might be used to perform Mars Sample Return with an Earth-direct architecture, and that this may offer a desirable simpler and lower cost approach. The objective of the study was to determine whether these capabilities can be used to optimize the number of mission systems and launches required to return the samples, with the goal of achieving the desired simplicity.All of the major element required for the Mars Sample Return mission are described. Mission system elements were analyzed with either direct techniques or by using parametric mass estimating relationships. The analysis shows the feasibility of a complete and closed Mars Sample Return mission design based on the following scenario: A SpaceX Falcon Heavy launch vehicle places a modified version of a SpaceX Dragon capsule, referred to as “Red Dragon”, onto a Trans Mars Injection trajectory. The capsule carries all the hardware needed to return to Earth Orbit samples collected by a prior mission, such as the planned NASA Mars 2020 sample collection rover. The payload includes a fully fueled Mars Ascent Vehicle; a fueled Earth Return Vehicle, support equipment, and a mechanism to transfer samples from the sample cache system onboard the rover to the Earth Return Vehicle. The Red Dragon descends to land on the surface of Mars using Supersonic Retropropulsion. After collected samples are transferred to the Earth Return Vehicle, the single-stage Mars Ascent Vehicle launches the Earth Return Vehicle from the surface of Mars to a Mars phasing orbit. After a brief phasing period, the Earth Return Vehicle performs a Trans Earth Injection burn. Once near Earth, the Earth Return Vehicle performs Earth and lunar swing-bys and is placed into a Lunar Trailing Orbit-an Earth orbit, at lunar distance. A retrieval mission then performs a rendezvous with the Earth Return Vehicle, retrieves the sample container, and breaks the chain of contact with Mars by transferring the sample into a sterile and secure container. With the sample contained, the retrieving spacecraft makes a controlled Earth re-entry preventing any unintended release of Martian materials into the Earth’s biosphere. The mission can start in any one of three Earth to Mars launch opportunities, beginning in 2022.

New trade tree for manned mars missions

Recent studies on human missions to Mars suggest revisiting the parameters that have the most important impact on the complexity, the initial mass in low Earth orbit, the risks and the development costs for the first journey to the red planet. In the last NASA reference mission, a trade tree is proposed.At first level, the parameter is the class of mission, e.g., conjunction (long surface stay) or opposition (short surface stay). This parameter is important but there is an agreement on the best option (conjunction). It is therefore not a relevant parameter of the decision tree. For the other levels, the parameters are as follows:•Launching sequence: pre-deploy or all-up.•Mars orbit insertion: aerocapture or propulsive.•Exploitation of local resources: yes/no.•Propulsion for interplanetary flight: chemical/nuclear thermal/electric.The relevance of these parameters is questionable. It is proposed to reexamine all parameters of the mission and to study their interdependency and the complexity and the costs of possible options. The first important parameter should be the size of the crew. It should be assigned to the top node of the tree, because its impact on the initial mass in low Earth orbit, costs and risks is probably higher than any other parameter. Another parameter is the strategy for Mars orbit insertion. It is suggested here that aerocapture is very important and that it brings acceptable constraints for the architecture of the mission. The third parameter should be the strategy for entry, descent and landing. The mass of the landing vehicle is very important, because it is tightly linked to the complexity of the entry, descent and landing phase. With a low mass, a capsule shape and a rigid heat shield can be chosen for this maneuver (lowest risk, highest technology readiness level). With a heavy vehicle, an inflatable heat shield might help but the qualification of the systems would be very difficult and the entry, descent and landing phase would be more complex. This parameter is clearly a driving parameter for the design of mission architecture because this part is one of the riskiest (clearly established in the NASA report), one of the most expensive in terms of development and tests costs and there are obvious impacts on other parameters of the mission. The fourth parameter should be the strategy for the return and the preparation of the Earth return vehicle. According to our study, this vehicle is the heaviest of the mission. Critical choices can be made here and can make a scenario simple or very complex.Interestingly, a small crew size facilitates the reduction of the mass for the landing vehicles, which in turn suggests simple solutions for the aerocapture of all vehicles and the preparation of the Earth return vehicle without requiring the development of nuclear propulsion systems. All in all, this study shows that the choices made for the NASA reference mission are systematically suboptimal and that new options deserve to be explored.

Revised scenario for human missions to Mars

We present a revised version of our scenario for human missions to Mars. The idea is to take into consideration the difficulties and constraints for entry, descent and landing by splitting the heavy vehicle into two smaller ones. The standard capsule shape is thus possible for aerocapture and landing on Mars. It is suggested to use the largest possible diameter such that the ballistic coefficient is minimized and the lift to drag ratio is kept small. The maneuvers for the descent and landing are then simplified and the risks are minimized. The scenario has been modified to cope with the new constraints. Different options have been taken into account. It is possible to land a small Mars ascent vehicle or to reuse the habitat lander for Mars ascent. All options perform as well as the others for the criterion of the initial mass in low Earth orbit. However, reusing the habitat lander allows a significant reduction of the size of the Earth return vehicle, which otherwise requires a huge launching capability.

Autonomy for Mars Rovers: Past, Present, and Future

The vehicles used to explore the Martian surface require a high degree of autonomy to navigate challenging and unknown terrain, investigate targets, and detect scientific events. Increased autonomy will be critical to the success of future missions. In July 1997, as part of NASA's Mars Pathfinder mission, the Sojourner rover became the first spacecraft to autonomously drive on another planet. The twin Mars Exploration Rovers (MER) vehicles landed in January 2004, and after four years Spirit had driven more than four miles and Opportunity more than seven miles-lasting well past their projected three-month lifetime and expected distances traveled. The newest member of the Mars rover family will have the ability to autonomously approach and inspect a target and automatically detect interesting scientific events. In fall 2009, NASA plans to launch the Mars Science Laboratory (MSL) rover, with a primary mission of two years of surface exploration and the ability to acquire and process rock samples. In the near future, the Mars Sample Return (MSR) mission, a cooperative project of NASA and the European Space Agency, will likely use a lightweight rover to drive out and collect samples and bring them back to an Earth return vehicle. This rover will use an unprecedented level of autonomy because of the limited lifetime of a return rocket on the Martian surface and the desire to obtain samples from distant crater walls.

Project [formula omitted]—a study for a manned Mars mission in 2031

This study deals with a manned mission which focuses on building an orbital station around Mars. The advantages in comparison to direct-landing scenarios are outlined and the necessary technology is described. The orbiting station prohibits contamination of and from the Red Planet and houses six astronauts in a 1100 days journey to Mars providing three pressurized modules: two of them will remain in a Low Mars Orbit for further human missions while the third module is used as an Earth Return Vehicle. A Bimodal Nuclear Thermal Propulsion System is used also for electrical power production. An advanced Environment Control and Life Support System, the necessary radiation shielding, human factors and crew selection criteria have been studied. The described partly reusable Mars Landing Module allows highest possible flexibility in the choice of landing scenario. The overall mission budgets in the fields of mass, power and costs have been estimated.

A MODEL COMPARISON FOR OPTIMAL MARS ASCENT TRAJECTORIES

Maximum payload Mars launch trajectories are computed for a nominal two-stage Mars ascent vehicle. This vehicle transfers a payload from the surface of Mars to a circular parking orbit about Mars in preparation for transferring the payload to an Earth return vehicle. Both gravity turn and pitch-rate control models for controlling the ascent vehicle's trajectory are investigated. For each case, a rather complicated nonlinear programming problem is obtained and then solved using a sequential quadratic programming algorithm.

Trajectory-based heating analysis for the European Space Agency/Rosetta earth return vehicle

A coupled, trajectory-based flowfield and material thermal-response analysis is presented for the European Space Agency proposed Rosetta comet nucleus sample return vehicle. The probe returns to earth along a hyperbolic trajectory with an entry velocity of 16.5 km/s and requires an ablative heat shield on the forebody. Combined radiative and convective ablating flowfield analyses were performed for the significant heating portion of the shallow ballistic entry trajectory. Both quasisteady ablation and fully transient analyses were performed for a heat shield composed of carbon-phenolic ablative material. Quasisteady analysis was performed using the two-dimensional axisymmetric codes RASLE and BLIMPK. Transient computational results were obtained from the one-dimensional ablation/conduction code CMA. Results are presented for heating, temperature, and ablation rate distributions over the probe forebody for various trajectory points. Comparison of transient and quasisteady results indicates that, for the heating pulse encountered by this probe, the quasisteady approach is conservative from the standpoint of predicted surface recession.

Mars Direct: Humans to the red planet by 1999

“Mars Direct”, is an approach to the space Exploration Initiative that allows for the rapid initiation of manned Mars exploration, possibly as early as 1999. The approach does not require any on-orbit assembly or refueling or any support from the Space Station or other orbital infrastructure. Furthermore, the Mars Direct plan is not merely a “flags and footprints” one-shot expedition, but puts into place immediately an economical method of Earth-Mars transportation, real surface exploratory mobility, and significant base capabilities that can evolve into a mostly self-sufficient Mars settlement. This paper presents both the initial and evolutionary phases of the Mars Direct plan. In the initial phase, only chemical propulsion is used, sendig 4 persons on conjunction class Mars exploratory missions. Two heavy lift booster launches are required to support each mission. The first launch delivers an unfueled Earth Return Vehicle (ERV) to the martian surface, where it fills itself with methane/oxygen bipropellant manufactured primarily out of indigenous resources. After propellant production is completed, a second launch delivers the crew to the prepared site, where they conduct regional exploration for 1.5 years and then return directly to Earth in the ERV. In the second phase of Mars Direct, nuclear thermal propulsion is used to cut crew transit times in half, increase cargo delivery capacity, and to create the potential for true global mobility through the use of CO 2 propelled ballistic hopping vehicles (“NIMFs”). In this paper we present both phases of the Mars Direct plan, including mission architecture, vehicle designs, and exploratory strategy leading to the establishment of a 48 person permanent Mars base. Some speculative thoughts on the possibility of actually colonizing Mars are also presented.