Final Report Summary - RITD (Re-entry: inflatable technology development in Russian collaboration)
Executive Summary:
A spacecraft re-entering the atmosphere of the Earth needs to be decelerated to enable a safe landing on the surface. This requires special hypersonic decelerator systems to slow down the orbital speed by several thousands of kilometers per hour as well as heat shield systems for the protection against the high temperatures that can reach several hundreds of degrees of centigrade, due to atmospheric friction. The RITD project has successfully investigated the feasibility of utilizing the innovative inflatable Mars Entry, Descent and Landing system (EDLS) of the Mars MetNet Lander (MNL) for a spacecraft mission re-entering the atmosphere of the Earth. This Earth re-entry spacecraft is called MetNet-E. Accordingly, an EDLS that had been developed and optimized for a Martian atmospheric entry was analyzed and tested for use during terrestrial atmospheric re-entry.
The principal innovative aspects of the inflatable EDLS, compared to conventional rigid systems, include huge savings in overall mass and volume, as well as added utilization flexibility. The RITD project focused on analyzing and measuring the stability of the re-entry vehicle in the transonic phase of the brand new re-entry and descent system for low mass payloads that could be delivered by MetNet-E.
The RITD project developed the concept and preliminary design of an Earth atmospheric re-entry and descent system concept of MetNet-E based on inflatable hypersonic decelerator techniques that were originally developed for Mars by the MML. We assessed the benefits of this technology when deploying small payloads from Low Earth Orbit (LEO) to the surface of the Earth with modest costs. The EDLS design that was developed appears to be applicable for the entire relevant range of aerodynamic regimes expected to be encountered in the Earth’s atmosphere during entry, descent and landing. Envisaged applications using this EDLS approach include returning payloads of 4-8 kg down to the surface from LEO and even as part of the Earth return segment of a lunar mission.
Our development and assessments show clearly that this kind of inflatable technology originally developed for the Martian atmosphere with MML, is feasible for use for Earth entry and descent applications by MetNet-E with minor modifications.
Our analyses of the existing technologies and current trends have indicated that the kind of inflatable technology pursued by RITD has a high potential to enhance the European space technology expertise. This kind of technology is clearly feasible for utilization by Earth entry and descent applications within Europe.
This work has also effectively fostered a highly active and working collaboration between major Russian and European space research organizations providing new knowledge on the re-entry systems.
Project Context and Objectives:
Earth, most of the Solar System's planets and some moons have significant atmospheres. Significant in the sense that the atmosphere needs to be taken into account when missions landing on such celestial bodies are contemplated and designed. All such spacecraft need on the one hand be protected from the effects of the atmosphere but on the other hand the atmosphere can be used to decelerate the craft, hence reducing or removing the need for propulsive deceleration methods. The deceleration process presents difficult technical (thermal and aerodynamic) challenges due to the typically large velocity changes involved. Large amounts of kinetic energy needs to be converted to heat as well as the craft needing to pass through several aerodynamic velocity regimes (from high hypersonic to subsonic).
Rigid heat-shield technologies have been developed and implemented for missile and space mission uses. The solutions are, however, characteristically heavy resulting in a substantial payload penalty. The organizations participating in this proposal have been, for some, time developing a new and innovative alternative approach for spacecraft deceleration in atmospheres – based on inflatable structures. Inflatable structures hold the promise of considerable mass savings compared to the traditional approaches and hence improved payload-to-total-mass ratio. This development has been carried out in the context of the MetNet Lander (MNL) – a semi-hard Mars lander vehicle primarily intended for atmospheric science and meteorological uses, but potentially applicable for deployment of other small-mass payloads as well.
To enhance and add to the existing body of work, the work included in this proposal is to analyze and test the feasibility of the MNL's for use in Earth's atmosphere (and through scaling in other planetary atmospheres) in the transonic velocity regime, i.e. at speeds slightly above and down to slightly below the speed of sound (Mach 1.2 down to Mach 0.8).
The main objective has been to provide a demonstrated and verified EDLS design for the entire relevant range of aerodynamic regimes expected to be encountered in Earth's atmosphere during the entry, descent and landing.
As alluded to earlier, this new EDLS design concept allow both mass and volume savings compared to conventional technology, and is easily reconfigurable to different payload sizes.
The inflatable entry system concept has been studied previously for higher payload masses. From 2001 to 2009 the inflatable entry descent and landing system for Martian atmosphere was developed by FMI and the MetNet team. This project targets to analyze and test the transonic behavior of a small payload entry system to Earth's atmosphere. The concept and design studied and tested in this project has already been developed for entry into the Martian atmosphere and needs to be scaled for Earth's conditions. Hence scaling and adaptation for terrestrial conditions, instead of a completely new design, is a favorable approach for providing a new re-entry vehicle for terrestrial space applications.
The project has contributed towards assessment of the feasibility and applicability of the EDLS system for Earth's atmosphere by focusing on an aerodynamic transition regime. The focus has translated to computational model and limited-scope testing, allowing evaluation of the current EDLS/MNL design for Earth conditions and modifications required.
The project has been built upon earlier and ongoing collaborative development between organizations in EU member countries and Russia. Hence this project has been both a natural complement to and expansion of previous work as well as involving key EU and Russian participants. The participating EU member countries, also members of ESA, potentially open avenues of exploitation to results in ESA and in its collaborative programmes with other space agencies as well. The goal is to offer the EDLS as a Russo-European contribution to relevant future missions and programmes utilizing and exploring the space and its resources.
This project was planned in a structural manner starting from a background and feasibility analysis and then progressing to an analysis of development and modification needs of the existing MetNet design and eventually an aerodynamic analysis and wind tunnel testing of a mock-up model.
Project Results:
Please see the attached Final Report deliverable (in PDF format).
Potential Impact:
Multipurpose Inflatable Lander for Earth, Mars and Beyond:
Successful modification of the Mars MetNet Lander concept lander, MetNet-E, for Earth atmospheric re-entry opens new visions on how to implement future planetary missions, cargo delivery from the orbit missions as well as sample return missions from the solar system. In the frame of the RITD project, the consortium defined the frame where each considered lander could operate feasibly and what main issues have to be consider when defining the mission. As a result, the RITD project defined five lander categories and the key applications where each of the lander could be utilized. This categorization will be the base for consortium member institutes when planning new missions and scenarios. The aim and wish of the RITD project and partners is that this kind of categorization would be implemented as European approach for future missions carried out by the inflatable descent and landing structures.
The RITD MetNet-E lander design as such has a large variety of possible applications that can be realized in near future, as in the frame of the project the structure, main components of the lander and radio system for Earth re-entry communication were defined in reasonable detailed level.
As a result of the RITD project we have a complete first design of the multipurpose inflatable lander that has already proven to be feasible for Mars mission (MetNet-M, studied and qualified 2003-2010) and now, with some modifications and redesign, for wide range of Earth re-entry applications (MetNet-E). The future impact of the work from this RITD project is that the promising wide application range and areas of the RITD based inflatable concept shall be thoroughly investigated. Tentatively there are not any bigger reasons why the concept cannot be utilized on other planets and moons that have an atmosphere and can be used for deceleration of the landing vehicle. In addition to Mars and Earth applications, at least there should be detailed studies on how the MetNet-E/MetNet-M should be modified to be used in Venus (MetNet-V) and Jupiter moon of Titan (MetNet-T) atmospheres. The potential future impacts for the European planetary research and space sector in general would be very high and the multipurpose inflatable lander vehicle with a wide range of applications could significantly increase the exploitation of our solar system.
Realistic and Promising Scenarios for Near Future European Space Missions:
Based on the MetNet and RITD projects experiences and studies, the mission scenarios and planning of the possible realistic near future applications for the concepts were made at a preliminary level and proposed for the wider European space sector operators. The RITD consortium surveyed the possible applications where the impact of the inflatable landers would be the highest and following three scenarios emerged.
1) Mission Concept: Deployment of Cargo from ISS to Earth Surface
2) Mission Concept: De-orbiting of Low Earth Orbit Spacecraft
3) Mission Concept: Sample Return
These three mission proposals are realistic and can be realized today with the effective schedule above.
The potential impact of the using the MetNet-E as a part of the ISS cargo delivery system is huge, especially today when there are limited cargo transportation possibilities to and from ISS. The obvious advantages and where to most of the potential impacts of the MetNet-E exist, is the payload overall mass –ratio that makes it possible to bring the scientifically or otherwise valuable cargo more frequently and with more mass down to Earth. The one advantage and impact of the multipurpose MetNet-E lander is that similar methods and procedures used in the ISS cargo delivery scenario can be fairly easy with minor modifications implement to the sample return mission scenario introduced in the bullet two above as well as for the de-orbiting mission scenario.
A resulting impact from this project is the confirmation that a sub-orbital test launch is required. Most of the properties of the landing MetNet-E vehicle can be calculated, simulated and tested in wind tunnels with small-scale models, but to fully qualify the inflatable landing vehicle there is a need for real-size landing vehicle atmospheric re-entry test in real mission environment. The RITD consortium has acknowledged and agreed that next step shall be preparing and executing this kind of test mission.
It has to be noted that despite the RITD project concentrated on the investigations of the MetNet-E Earth re-entry parameters and implementation, a spin-off was the project contributed significantly to the development of the MetNet-M also, by providing new knowledge e.g. regarding the stability and other important parameters of the landing vehicle. This impact to the future development of the MetNet-M, and other landing vehicles based on the same basic concept (e.g. MetNet-V and MetNet-T introduced earlier), should not be underestimated.
Sustainable Co-operation:
The co-operation and research activities performed during the RITD project enhanced and deepened already long-standing co-operation between the parties. Based on the experiences from the RITD project and emerged future development needs for realising the full-scale mission, the consortium agreed on sustaining the formed and working co-operation network in future. The future impact of this mutual agreement is that the achieved project results will be utilized in future European (EU, ESA, etc.) projects and proposals as efficiently as possible. All RITD partners agreed actively seek opportunities for new continuation projects that would advance the resolving of the emerged development needs.
First issue that RITD consortium will investigate after the RITD activities are officially over, is the compiling of the first solid mission plan of the sub-orbital test launch, as it was identified as one of the most crucial future development needs and activities in order to take next big steps for realising the full-scale mission. The impact of maintaining and running the co-operation activities between the parties is that the development work of the European inflatable technology and investigations progress and knowhow is maintained for the future.
The ultimate goal of the future co-operation activities is to perform similar type of mathematical analyses and laboratory test programs as in the case of the MetNet-E for all lander 1 to 5 categories presented earlier and fully qualify of the entire fleet of the EU-Russian inflatable landers, which can be utilized in both Earth re-entry and other celestial objects re-entry missions in the future.
Improving the Visibility among the European Space Sector:
One very important impact of the RITD project is the improving of the visibility and awareness of the EU-Russian co-operation activities and joint efforts in developing the novel multipurpose inflatable landing vehicle. The MetNet-M landing vehicle is somehow known among the European space sector operators, but the modified and improved lander vehicle for earth, MetNet-E, raised the developed concept as a potentially viable option for the future European lander on Mars and on Earth. The received public attention has and will increase the confidence on the MetNet-E concept and opens new opportunities to utilize the concept and deepen the investigations with the help of bigger European consortium. The full impact of 13 conference presentations in eight countries (Spain, UK, Portugal, Russia, Austria, France, China and Canada), articles written and to be written will be measured in later in next few years when assembling new consortiums for continuation projects of the RITD project.
List of Websites:
http://ritd.fmi.fi
Coordinator: Ari-Matti Harri (email: Ari-Matti.Harri@fmi.fi)
A spacecraft re-entering the atmosphere of the Earth needs to be decelerated to enable a safe landing on the surface. This requires special hypersonic decelerator systems to slow down the orbital speed by several thousands of kilometers per hour as well as heat shield systems for the protection against the high temperatures that can reach several hundreds of degrees of centigrade, due to atmospheric friction. The RITD project has successfully investigated the feasibility of utilizing the innovative inflatable Mars Entry, Descent and Landing system (EDLS) of the Mars MetNet Lander (MNL) for a spacecraft mission re-entering the atmosphere of the Earth. This Earth re-entry spacecraft is called MetNet-E. Accordingly, an EDLS that had been developed and optimized for a Martian atmospheric entry was analyzed and tested for use during terrestrial atmospheric re-entry.
The principal innovative aspects of the inflatable EDLS, compared to conventional rigid systems, include huge savings in overall mass and volume, as well as added utilization flexibility. The RITD project focused on analyzing and measuring the stability of the re-entry vehicle in the transonic phase of the brand new re-entry and descent system for low mass payloads that could be delivered by MetNet-E.
The RITD project developed the concept and preliminary design of an Earth atmospheric re-entry and descent system concept of MetNet-E based on inflatable hypersonic decelerator techniques that were originally developed for Mars by the MML. We assessed the benefits of this technology when deploying small payloads from Low Earth Orbit (LEO) to the surface of the Earth with modest costs. The EDLS design that was developed appears to be applicable for the entire relevant range of aerodynamic regimes expected to be encountered in the Earth’s atmosphere during entry, descent and landing. Envisaged applications using this EDLS approach include returning payloads of 4-8 kg down to the surface from LEO and even as part of the Earth return segment of a lunar mission.
Our development and assessments show clearly that this kind of inflatable technology originally developed for the Martian atmosphere with MML, is feasible for use for Earth entry and descent applications by MetNet-E with minor modifications.
Our analyses of the existing technologies and current trends have indicated that the kind of inflatable technology pursued by RITD has a high potential to enhance the European space technology expertise. This kind of technology is clearly feasible for utilization by Earth entry and descent applications within Europe.
This work has also effectively fostered a highly active and working collaboration between major Russian and European space research organizations providing new knowledge on the re-entry systems.
Project Context and Objectives:
Earth, most of the Solar System's planets and some moons have significant atmospheres. Significant in the sense that the atmosphere needs to be taken into account when missions landing on such celestial bodies are contemplated and designed. All such spacecraft need on the one hand be protected from the effects of the atmosphere but on the other hand the atmosphere can be used to decelerate the craft, hence reducing or removing the need for propulsive deceleration methods. The deceleration process presents difficult technical (thermal and aerodynamic) challenges due to the typically large velocity changes involved. Large amounts of kinetic energy needs to be converted to heat as well as the craft needing to pass through several aerodynamic velocity regimes (from high hypersonic to subsonic).
Rigid heat-shield technologies have been developed and implemented for missile and space mission uses. The solutions are, however, characteristically heavy resulting in a substantial payload penalty. The organizations participating in this proposal have been, for some, time developing a new and innovative alternative approach for spacecraft deceleration in atmospheres – based on inflatable structures. Inflatable structures hold the promise of considerable mass savings compared to the traditional approaches and hence improved payload-to-total-mass ratio. This development has been carried out in the context of the MetNet Lander (MNL) – a semi-hard Mars lander vehicle primarily intended for atmospheric science and meteorological uses, but potentially applicable for deployment of other small-mass payloads as well.
To enhance and add to the existing body of work, the work included in this proposal is to analyze and test the feasibility of the MNL's for use in Earth's atmosphere (and through scaling in other planetary atmospheres) in the transonic velocity regime, i.e. at speeds slightly above and down to slightly below the speed of sound (Mach 1.2 down to Mach 0.8).
The main objective has been to provide a demonstrated and verified EDLS design for the entire relevant range of aerodynamic regimes expected to be encountered in Earth's atmosphere during the entry, descent and landing.
As alluded to earlier, this new EDLS design concept allow both mass and volume savings compared to conventional technology, and is easily reconfigurable to different payload sizes.
The inflatable entry system concept has been studied previously for higher payload masses. From 2001 to 2009 the inflatable entry descent and landing system for Martian atmosphere was developed by FMI and the MetNet team. This project targets to analyze and test the transonic behavior of a small payload entry system to Earth's atmosphere. The concept and design studied and tested in this project has already been developed for entry into the Martian atmosphere and needs to be scaled for Earth's conditions. Hence scaling and adaptation for terrestrial conditions, instead of a completely new design, is a favorable approach for providing a new re-entry vehicle for terrestrial space applications.
The project has contributed towards assessment of the feasibility and applicability of the EDLS system for Earth's atmosphere by focusing on an aerodynamic transition regime. The focus has translated to computational model and limited-scope testing, allowing evaluation of the current EDLS/MNL design for Earth conditions and modifications required.
The project has been built upon earlier and ongoing collaborative development between organizations in EU member countries and Russia. Hence this project has been both a natural complement to and expansion of previous work as well as involving key EU and Russian participants. The participating EU member countries, also members of ESA, potentially open avenues of exploitation to results in ESA and in its collaborative programmes with other space agencies as well. The goal is to offer the EDLS as a Russo-European contribution to relevant future missions and programmes utilizing and exploring the space and its resources.
This project was planned in a structural manner starting from a background and feasibility analysis and then progressing to an analysis of development and modification needs of the existing MetNet design and eventually an aerodynamic analysis and wind tunnel testing of a mock-up model.
Project Results:
Please see the attached Final Report deliverable (in PDF format).
Potential Impact:
Multipurpose Inflatable Lander for Earth, Mars and Beyond:
Successful modification of the Mars MetNet Lander concept lander, MetNet-E, for Earth atmospheric re-entry opens new visions on how to implement future planetary missions, cargo delivery from the orbit missions as well as sample return missions from the solar system. In the frame of the RITD project, the consortium defined the frame where each considered lander could operate feasibly and what main issues have to be consider when defining the mission. As a result, the RITD project defined five lander categories and the key applications where each of the lander could be utilized. This categorization will be the base for consortium member institutes when planning new missions and scenarios. The aim and wish of the RITD project and partners is that this kind of categorization would be implemented as European approach for future missions carried out by the inflatable descent and landing structures.
The RITD MetNet-E lander design as such has a large variety of possible applications that can be realized in near future, as in the frame of the project the structure, main components of the lander and radio system for Earth re-entry communication were defined in reasonable detailed level.
As a result of the RITD project we have a complete first design of the multipurpose inflatable lander that has already proven to be feasible for Mars mission (MetNet-M, studied and qualified 2003-2010) and now, with some modifications and redesign, for wide range of Earth re-entry applications (MetNet-E). The future impact of the work from this RITD project is that the promising wide application range and areas of the RITD based inflatable concept shall be thoroughly investigated. Tentatively there are not any bigger reasons why the concept cannot be utilized on other planets and moons that have an atmosphere and can be used for deceleration of the landing vehicle. In addition to Mars and Earth applications, at least there should be detailed studies on how the MetNet-E/MetNet-M should be modified to be used in Venus (MetNet-V) and Jupiter moon of Titan (MetNet-T) atmospheres. The potential future impacts for the European planetary research and space sector in general would be very high and the multipurpose inflatable lander vehicle with a wide range of applications could significantly increase the exploitation of our solar system.
Realistic and Promising Scenarios for Near Future European Space Missions:
Based on the MetNet and RITD projects experiences and studies, the mission scenarios and planning of the possible realistic near future applications for the concepts were made at a preliminary level and proposed for the wider European space sector operators. The RITD consortium surveyed the possible applications where the impact of the inflatable landers would be the highest and following three scenarios emerged.
1) Mission Concept: Deployment of Cargo from ISS to Earth Surface
2) Mission Concept: De-orbiting of Low Earth Orbit Spacecraft
3) Mission Concept: Sample Return
These three mission proposals are realistic and can be realized today with the effective schedule above.
The potential impact of the using the MetNet-E as a part of the ISS cargo delivery system is huge, especially today when there are limited cargo transportation possibilities to and from ISS. The obvious advantages and where to most of the potential impacts of the MetNet-E exist, is the payload overall mass –ratio that makes it possible to bring the scientifically or otherwise valuable cargo more frequently and with more mass down to Earth. The one advantage and impact of the multipurpose MetNet-E lander is that similar methods and procedures used in the ISS cargo delivery scenario can be fairly easy with minor modifications implement to the sample return mission scenario introduced in the bullet two above as well as for the de-orbiting mission scenario.
A resulting impact from this project is the confirmation that a sub-orbital test launch is required. Most of the properties of the landing MetNet-E vehicle can be calculated, simulated and tested in wind tunnels with small-scale models, but to fully qualify the inflatable landing vehicle there is a need for real-size landing vehicle atmospheric re-entry test in real mission environment. The RITD consortium has acknowledged and agreed that next step shall be preparing and executing this kind of test mission.
It has to be noted that despite the RITD project concentrated on the investigations of the MetNet-E Earth re-entry parameters and implementation, a spin-off was the project contributed significantly to the development of the MetNet-M also, by providing new knowledge e.g. regarding the stability and other important parameters of the landing vehicle. This impact to the future development of the MetNet-M, and other landing vehicles based on the same basic concept (e.g. MetNet-V and MetNet-T introduced earlier), should not be underestimated.
Sustainable Co-operation:
The co-operation and research activities performed during the RITD project enhanced and deepened already long-standing co-operation between the parties. Based on the experiences from the RITD project and emerged future development needs for realising the full-scale mission, the consortium agreed on sustaining the formed and working co-operation network in future. The future impact of this mutual agreement is that the achieved project results will be utilized in future European (EU, ESA, etc.) projects and proposals as efficiently as possible. All RITD partners agreed actively seek opportunities for new continuation projects that would advance the resolving of the emerged development needs.
First issue that RITD consortium will investigate after the RITD activities are officially over, is the compiling of the first solid mission plan of the sub-orbital test launch, as it was identified as one of the most crucial future development needs and activities in order to take next big steps for realising the full-scale mission. The impact of maintaining and running the co-operation activities between the parties is that the development work of the European inflatable technology and investigations progress and knowhow is maintained for the future.
The ultimate goal of the future co-operation activities is to perform similar type of mathematical analyses and laboratory test programs as in the case of the MetNet-E for all lander 1 to 5 categories presented earlier and fully qualify of the entire fleet of the EU-Russian inflatable landers, which can be utilized in both Earth re-entry and other celestial objects re-entry missions in the future.
Improving the Visibility among the European Space Sector:
One very important impact of the RITD project is the improving of the visibility and awareness of the EU-Russian co-operation activities and joint efforts in developing the novel multipurpose inflatable landing vehicle. The MetNet-M landing vehicle is somehow known among the European space sector operators, but the modified and improved lander vehicle for earth, MetNet-E, raised the developed concept as a potentially viable option for the future European lander on Mars and on Earth. The received public attention has and will increase the confidence on the MetNet-E concept and opens new opportunities to utilize the concept and deepen the investigations with the help of bigger European consortium. The full impact of 13 conference presentations in eight countries (Spain, UK, Portugal, Russia, Austria, France, China and Canada), articles written and to be written will be measured in later in next few years when assembling new consortiums for continuation projects of the RITD project.
List of Websites:
http://ritd.fmi.fi
Coordinator: Ari-Matti Harri (email: Ari-Matti.Harri@fmi.fi)