Sunday, 2 September 2012

On twitter now :)

I just signed up for twitter, follow us on #thomas_sinn for more frequent updates on the Self-inflating Adaptive Membrane.

Tuesday, 31 July 2012

100k contract to company manufacturing inflatable rigidizing satellite parts

The company Space Ground Amalgam, LLC got awarded the first prize of $100,000 at last Saturday 's 2012 NewSpace Business Plan Competition (NASA funded). This competition has the purpose to help startup space companies that create potentially game-changing technologies. Space Ground Amalgam, LLC will look at inflatable antennas and rigidization techniques for very large structures. The company is in a partnership with the famous inflatable manufacturer L'Garde (CA, USA). They will also look into post rigidization optimization. Application areas are 30GHz antennas but it is planned to expand to solar arrays. Great to hear that there is research undertaken in inflatable structure with the industry backing it up. Lets see how SAM can benefit from this news :).



Thursday, 19 July 2012

SAM presented in ICES (San Diego, CA, USA) as part of Mars Base 10

New application areas of SAM were presented at this week’s AIAA International Conference on Environmental Systems (ICES) in San Diego. The paper had the title “Inflatable Structures for Mars Base 10” and was given in the Space Architecture Section. The paper covered inflation simulation of the Mars Base 10 which enables a crew of 10 astronauts to work permanently on the surface of Mars. Research on Mars Base 10 was first presented in 2008 by Ondrej Doule from the International Space University (Strasbourg, France). The Self-inflating Adaptive Membrane (SAM) has various application areas in and around Mars Base 10; they can be used as transmission antennas, solar concentrators adjusting the focal point based on the season to increase their efficiency or as sun shields also in form of small shelters to protect parts of Mars Base 10 or any deployed scientific, mining, or transportation hardware against radiation and Martian sand storms. They can be used for portable EVA shelters for crew as well as hardware. Further application may include also components of deployable exploration flyers and backup hardware. The big advantage of these structures is that they can be deployed out of a small container wherever, whenever they are needed. It is therefore not necessary to transport the deployed structure first into earth orbit and then to Mars. The transport of SAM in the storage box also decreases the risks of damaging the structure on the journey to Mars from micro meteoroids or high radiation environments for example in the van-Allen belts.

Tuesday, 10 July 2012

SAM UK Space Agency Study finished

Over the last six month, researchers at the Advanced Space Concepts Laboratory of the University of Strathclyde were working on a UK Space Agency Study with the topic “CubeSat Low Cost Inter-Orbit Transfer Demonstrator”. SAM was one of the two proposed satellite missions that would enable low cost inter-orbit transfer. SAM would use hybrid propulsion consisting of a solar sail and an electric engine. The cube satellite membrane would employ the SAM membrane as a substructure with integrated solar cells powering the electric engines. The study showed that such a system would enable a low cost transfer of a 3U cube satellite from the Earth to the Moon. We are hoping for a follow-up study from the UK Space Agency for SAM to become UK’s next satellite UKube 3 or UKube 4.

StrathSat-R Critical Design Review

Last week, the StrathSat-R team had the Critical Design Review (CDR) at DLR Oberpfaffenhofen. The team presented the design and the status of the experiment and received feedback from experts from ESA, DLR and SNSB. Passing this CDR was an important step of getting closer to the rocket launch in March 2013. The StrathSat-R experiment will be on the REXUS 13 rocket together with the other European Experiments: Polecats and Space Sailors, and Muscats.

Furthermore, the pumps on the experiment got changed to stronger ones due to the requirement that all the actuation needs to be performed within 140 seconds of micro gravity time. The smaller pumps from earlier in the project were selected because the assumption was made that they would be suitable due to the low mass of the trapped air. Experiments showed that the trapped air mass is indeed low but the volume is large. Therefore, pumps with a higher mass flow rate should also be able to change the volume changing capabilities.

The research on SAM is currently focused on creating a Matlab code to simulate the actuation of the SAM membrane.  At the moment, the research is carried out parallel to attending the Space Studies Program (SSP) of the International Space University (ISU) in Melbourne, Florida in conjunction with the Florida Institute of Technology and NASA’s Kennedy Space Center.

Tuesday, 22 May 2012

First shape change tests in vacuum chamber

Today, vacuum tests for the spheres and the micro pumps were carried out to test the volume changing capabilities of SAM’s spheres. In the finished structure the volume change between two neighbouring spheres will result in a shape change of the entire structure. For today’s test two inflatable spheres were connected by a micro pump (Bartels Mikrotechnik GmbH) and tested first at ambient pressure and then in the vacuum chamber. It can be confirmed that the pumps worked in vacuum conditions, but the volume change was too slow (especially by considering the short micro gravity time of the sounding rocket experiment of roughly 140s). Further research will be focused on increasing the flow rate or maybe changing to more powerful pumps. Thanks to the Strathclyde students Thomas Perry and Paul Hammond for getting the micro pumps ready for today’s test.

Wednesday, 16 May 2012

SAM on BBC2 Scotland

Yesterday night, a feature on Space-based Solar Power was aired on BBC2's Newsnight Scotland. The piece also shows Strathclyde's Self-inflating Adaptive Membrane together with the cube satellites, in the vacuum chamber and the simulation. Further references are made to Strathclyde's Suaineadh experiment which was launched in March this year and had the purpose to show the feasibility of deploying a web in space by using centrifugal forces.

The article:

Newsnight Scotland on BBC Iplayer (at around 14minutes): 

Thursday, 10 May 2012

Simulations on SAM deployment progressing

For the last couple of weeks, simulations on the deployment behaviour of the inflating spheres from the StrathSat-R REXUS cube satellites were carried out. LS-DYNA with an academic license of the University of Strathclyde was used for the deployment simulation. Two rows of 18 spheres were modelled with a constrained rigid cube satellite in the centre. To simulate the deployment from the cube, the flat spheres (two sheets of polymer joined together around their circumference) where pressed into the cube satellite first. After the spheres were stored, the residual air inflation deploys the entire structure. This “chaotic” storage followed by the residual air inflation can be seen in the attached clip. Current research is now focused on modelling different folding pattern in LS-DYNA and starting a code to program the shape change of the membrane.

BBC doing a piece on Space Power Satellites at Strathclyde

Today, reporters from the BBC were at the University of Strathclyde to do a piece on Space Based Solar Power. The researchers's at Strathclyde are involved in the current NIAC (NASA Institute for Advanced Concepts) study on Space Power Satellites (SPS) called SPS-ALPHA with John C. Mankins from Artemis Innovation as a project lead. Space Based Solar Power is the promising concept of collecting the sun’s energy in space and then transmitting it via laser or microwaves to the ground. With this concept the energy can be harvested more efficiently without losing too much of the sun’s energy through the Earth’s atmosphere. These Space Power Satellites (SPS) are huge structures with diameters in the order of hundreds of meters. Large deployable structures become necessary to realise such an ambitious project. The smart structure of the Self-inflating Adaptive Membrane can be used as a reflector or concentrator to focus the Sun’s energy on the solar cells before transmitting it via microwaves or lasers to the ground. Further applications can be seen as all kinds of substructures for the SPS concept due to SAM’s adaptability. The piece will be aired probably on Monday (14th of May 2012) evening on BBC. 

Micropumps are working under ambient conditions

The breadboard electronics for the micropumps (Bartels Mikrotechnik GmbH) was build last week and a first test was carried out at ambient conditions with water to prove the functionality of the microcontroller and the pumps. The tests were fully successful. Currently the team is in preparation for testing the capabilities of the pumps in vacuum conditions. This test will be carried out next week at the physics lab here at Strathclyde. Two of SAM’s inflatable sphere will be connected by a micropump to investigate the volume changing capabilities which will enable SAM’s adaptability.

Monday, 30 April 2012

Manufacturing progressing

The first prototype full structure of SAM for the REXUS 13/14 sounding rocket mission was manufactured last week by Strathclyde student Adnan Mahmood. The full structure has 18 circular elements in two rows. During the last couple of week Adnan improved the manufacturing technique by using a heated ring to heat seal the spheres made out of alluminized PET (Polyethylene Terephthalate) commonly found in heat and rescue blankets. The picture to the right shows the vacuum inflation of two spheres connected in the middle point (connection points between the rows).

13th Gossamer Structures Systems Forum

Last Tuesday, SAM got presented at the Inflatable Structures Session of the 13th Gossamer Structures System Forum at the Waikiki Sheraton in Hawaii. The paper had the ID AIAA-2012-1517 and the title "Design and Development of a Deployable Self-inflating Adaptive Membrane. The presentation was well received by the roughly 80 people in the audience. SAM got useful comments and feedback to improve SAM's design further.

Monday, 16 April 2012

Abstract for 63rd International Astronautical Congress 2012 in Naples have been accepted

The abstracts for three papers focusing on the self-inflating adaptive membrane concept have been accepted for the 63rd International Astronautical Congress from the 1st until the 5th of October 2012 in Naples, Italy. The first paper explains the idea, design and principle behind the concept with the title "Bio-inspired programmable matter for space applications" which will be presented in C2.5 (C2 Materials and Structure Symposium, Session 5: Smart Materials and Adaptive Structures). The second paper deals with an application of the membrane as a method of mitigating space debris. The paper’s title is “Space debris removal using a self-inflating adaptive membrane” which is going to be presented in A6.5 (A6 Space Debris Symposium, Session 5: Space Debris Removal Issues). The last paper was accepted for the student team competition and it will give an overview of the experiment StrathSat-R (including SAM) which will be launched on board REXUS 13/14 in March 2013. The paper has the title “StrathSat-R: Deploying inflatable CubeSat structures in micro gravity” and will be presented in the E2.3 (E2 42nd Student Conference, Session 3: Student Team Competition).

Tuesday, 3 April 2012

Paper on SAM submitted for AIAA's 53rd Structures, Structural Dynamics, and Materials Conference (SDM)

Last night, the paper on SAM with the title "Design and Development of a Self-inflating Adaptive Membrane" was submitted to the 53rd Structures, Structural Dynamics, and Materials Conference (SDM). The conference will take place in Honolulu, Hawaii from the 23rd till 26th of April 2012. SAM’s paper outlines the idea behind the bio-inspired membrane, an explanation of the residual air inflation technique, an overview over manufacturing techniques and a comparison of different folding pattern to decrease SAM’s storage volume. The paper concludes with a summary of SAM’s technology demonstrator mission on-board REXUS13/14. Thomas Sinn will participate in the conference and will present the paper at the 13th AIAA Gossamer Systems Forum which is part of the 53rd Structures, Structural Dynamics, and Materials Conference (SDM). Exact date and time of the presentation still needs to be confirmed.

Monday, 26 March 2012

Manufacturing of inflatable structure

During the last couple of days, Adnan Mahmood worked on the optimization of the manufacturing techniques for the deployable part of SAM. Various structures were manufactured and tested in the vacuum chamber of the physic's department of the University of Strathclyde. The first full scale structure is scheduled to be finished until mid April. A first mating between the cube satellite structure and the deployable structure will commence shortly after.

Thursday, 23 February 2012

Micro pumps arrived + StrathSat-R's PDR

Yesterday, the micro pumps from Bartels Mikrotechnik (; Dortmund, Germany) arrived at the University of Strathclyde. The pumps have the purpose to act as an actuator element for the Self-inflating Adaptive Membrane (SAM) for the REXUS sounding rocket experiment StrathSat-R. SAM consists of two layers of inflatable spheres. By changing the pressure between two adjacent cells, the shape of the entire membrane can be changed.

Next week the team will travel to Kiruna (Sweden) for the Preliminary Design Review (PDR) of the sounding rocket experiment. The workshop and review is held by the German Aerospace Center (DLR), the Swedish National Space Board (SNSB) and the European Space Agency (ESA).

Description of the REXUS 13/14 sounding rocket experiment SAM

In the following the layout of the REXUS13/14 sounding rocket experiment SAM will be described. The deployable structure of SAM consists of two rows of spherical cells that are deployed by using the expansion of trapped air in the spheres when subjected to vacuum (space) conditions. The two layers of spheres are manufactured out of 30micron reflectively coated Mylar. Each cell is manufactured by heat welding circular sheets of Mylar together. The diameter of each cell is 14 cm; the diameter of the entire structure is 98 cm. The connection between the ejectable module and the deployable structure is obtained with an adhesive.

In order to change the shape of the structure, micro pumps are added to vary the trapped air pressure between two neighbouring cells. The pressure change in these cells will then change the volume of the two spheres and therefore change the shape of the entire structure. This bio-inspired structure originates from the heliotropism of plants (movement of plants towards the sun).

Mp6 micro pumps from Bartels Mikrotechnik GmbH (Dortmund, Germany) are used to change the pressure between two cells. There will be two pumps mounted to the inside wall of the deployment storage. The rows of spheres closest to the sides of the cube are joined to form one big actuator. The micro pumps will pump the residual air from the bottom to the top layer of Actuator 1 to lift up the up side and respectively from the bottom to the top layer of Actuator 2 to lift up the down side of SAM. The control software will alternate between the actuation of Actuator 1 and Actuator 2. A more precise actuation timeline needs to be validated by tests of the pumps and the structure in the vacuum chamber.

Monday, 13 February 2012

New bio-inspired design

Simulations on the hexagonal structure showed that the current design had some major flaws which were making the shape change almost impossible to predict. Due to the fact that the hexagon is made up of six triangle elements, the inflatable volume is not similar everywhere which results in the displacement of the hexagon centre either up or down. This means that each hexagon could serve as an actuator that can be easily flipped between these two stages without a huge power consumption. At first it seemed like the ideal solution but by considering an array made up by thousands of these elements, the flipping of one element could trigger the unwanted flipping of hundreds of elements which will result in a chaotic final shape.

The research has been now focused on a new kind of design which is inspired by nature. The design is adapted from the heliotropism of plants. Heliotropism is the growth or movement of an organism, especially a plant, towards the direction of the sunlight. The motion of the plant is performed by motor cells in the flexible segment called pulvinus. The motor cells are pumping potassium ions into nearby tissues and therefore changing its turgor pressure of these cells. The segment flexes due to motor cells elongation at the shadow side due to turgor pressure rise.

By adding the principle of the residual air inflation and the new bio-inspired cell design, a versatile membrane can be obtained. The cells are manufactured by heat welding two thin circular Mylar sheets together. Two rows of inflatable cells with a reflective surface sheet on top and bottom form the membrane structure. In order to obtain the adaptability of the design, piezoelectric micro pumps are added between the two rows of cells to change the pressure between two neighbouring cells. By activating the micro pumps, the volume of the cells can be increased and decreased which results in a shape change of the entire membrane.

Research at the moment is focused on the modelling of the cells as a multibody system to understand the control of the structure. Furthermore, samples have been manufactured to validate the concept of the residual air inflation under vacuum with the new geometry. Additionally, Bartels Mikrotechnik GmbH (Dortmund, Germany) has graciously agreed to support the research and the REXUS sounding rocket with their micro pumps. Thank you very much.