Assessment of chemical propulsion systems for interplanetary missions
The success of space exploration will largely depend on the availability of reliable propulsion systems capable of fulfilling strict new requirements such as enabling fast transfer times, large payloads, soft landing on planets and sample return. Traditional propulsion systems such as chemical propulsion have performed well in traditional near-earth or deep space missions. But the relatively low energy they deliver for a given propellant mass imposes severe restrictions on Mars Sample Return-like missions requiring high changes in velocity.
Current descent and ascent propulsion technologies for future exploration missions have been shown to be suitable for sample return missions. Thrust level ranges, specific impulse level, independence from solar energy and reasonable development timeframe are adequate to meet mission requirements. However, many tradeoffs still remain to be performed concerning the best engines to be used for descent and ascent modules. These tradeoffs should primarily focus on the type of engine (monopropellant vs. bi-propellant, mono-stage vs. bi-stage), type of propellant (liquid vs. solid), etc.
This activity first addressed all the propulsion module technologies needed for a Mars Sample Return-like mission (i.e. orbiter, Mars Ascent Vehicle - MAV, Descent Module - DM). It assessed which are the most suitable possible solutions (along with market reviews) as well as the main parameters that have to be taken into account to perform trade-offs.
Once the issues were identified, the assessment focussed on the critical elements of the mission: descent module and MAV. Preliminary trade-offs have shown that monopropellant/one stage engine for the DM and bipropellant/bi-stage engine for the MAV are the most suitable solutions.
Another issue that has to be overcome is the use of a pump-fed propulsion system. It offers the advantage of a high-pressure combustion section (higher efficiency), while simultaneously keeping the pressure in the propellant feed system at a lower level, thus saving substantial propellant tank mass. Then, recommendations are given related to the type of engine to be used for those two vehicles. All those technologies have to be traded taking into account the rather harsh Martian environment.
This activity identified MAV engine options. However, even though MSR phase A2 studies as well as further MAV activities will greatly benefit this activity, inputs are mutual. System studies will lead to further assessment of the MSR mission mass budgets and EDLS systems which are the main drivers of the DM and MAV. An activity leading to a MAV flight model would be highly beneficial to evaluate real performances and reliability of the selected engine.
| Start |
Expected or actual duration | Status | Prime contractor |
|---|---|---|---|
| Jan '04 | 18 months | Completed | SAFRAN (SNECMA) |
Executive Summary