KSat

Hello K^2, I'm sorry that I was not able to read all the previous posts and you needed to repeat yourself. 1m/s^2 sounds better to me. Yes, I think magnetotorquers are the way to go for LEO cubesats. On our MIRKA2 Mission we are also going to use them. Liquid CO2 could be an option, it would degas itself, sustain pressure and for plants a 100% CO2 atmosphere is like fertilizer. Liquid nitrogen could be an option but is pretty inert and wouldnt do much. Something I am not quite sure about. It could be that if they plants are very industrious and they convert all the CO2 , that in the end a nearly 100% O2 atmosphere is present, you might have created a serious fire hazard. Which mould make for some nice final pictures I guess. Opening a valve could also be tricky for cubesats. Because it is often a launch requirement that gas tanks need to be physically sealed and are then in orbit opend by pyro valves (small explosives that punch through the seal). Currently no pytotechnics are allowed for cubesats. Everthing that belongs to NASA is very hard to get access to. Maybe if some of the americans knows some professorsfrom their universities that have direct connections to them. I doubt that this is possible. It is more likely that you will approach way to far off than your propulsion can provide to correct in the last moments. What do you mean by visual localization? If you mean startrackers, to calculate your position it is possible while correcting all the way. But if you mean looking where your target is and then propelling there, then it is nearly impossible. Pressurized tanks are the problem here. The cubesat requirements allow only for pressures of 1.2 bar. So the gas needs to be generated from storing liquids or solids. Electrospraythruster from Busek uses a ionizable liquid it has low thrust but high specific impulse. Other electric options could be the Clydespace pulsed plasma thruster but is probably off budget. Isobutane could be used as a cold gas generator. Or if you want it combustable you might go for water electrolysis. Sorry I do not have any experience in that yet. Cheers, KSat

Hello fellow Kerbonauts, I will post here some comments about the plannend stuff. But although I have some knowledge in spaceflight and spaceengineering, I might get some things room or have overseen some details. This plan is at least hardcore. You probably have in some simulation tool made already an example of a trajectory that could fit that. But the Computer simulations are always a simplistic version of reality. The gravity fields of moon and earth are not spheres and not even ellipsoids. On your interplanetary journey you have disturbances by solar wind and radiation pressure. You have burn errors, that are small (impossible to avoid) while burning, but they matter big in the end. Also the atmospheres are highly dynamic and the aerobreaking maneuver therefore highly uncertain. For example the upper atmospheric density depends on the solar activity, which will change during your mission time. All in all, this is very tricky and you would need alot of equipment that is able to detect and correct trajectory errors and safety margins for fuel. Also for interplanetary communication you would need acess to the Deep Space Network. Heatshields are a topic for themselves, ceramics are expensive and ablators are tricky to calculate. Conclusion: Slingshots maybe. Aerocapture hard. Cheers, KSat

Hello fellow Kerbonauts, I will post here some comments about the plannend stuff. But although I have some knowledge in spaceflight and spaceengineering, I might get some things room or have overseen some details. Smartphones are a cheap alternative to space qualified bord computers and have already flown. https://en.wikipedia.org/wiki/STRaND-1 https://en.wikipedia.org/wiki/PhoneSat For a missision of less then a month radiation should not be that harsh, but some shielding should be implemted. In general sensitive parts are placed in a spacecraft, where it is shielded by other less sensitive parts. Also from your orbit you can expect an increased radition flow from prograde direction (electrons). Tethers are great, but not that much tested yet. What you can do with a tether? Propulsion: You transfer some electric energy of your spacecraft into the orbit energy of your spacecraft. You therefore need some equipment that already has that electric energy. Gravity Gradient: Totally passive and no problem, especially not for a cubesat. The tether makes sure that the craft always points "down" to earth gravity center. Energy harvesting: Reverse process of propulsion. You trade your orbit energy for electrical energy. For example you can start a deorbit with a tether when you are able to dissipate the electrical energy into heat. It depends on your mission. If your starting orbit is high enough, you might be able to feed on your orbit energy until you start reentry. Therefore no other power generator would be necessary. If you plan a longer stay solar cells are needed and you would be able to maneuver in earth orbit. But one major concern. The elecitrical power by a tether is big and a cubesat is small, if you go for the tether you need to make sure you can survive the power output of the thether. Resistors would produce a lot of heat so probably a shorter tether is the easiest solution when power is to high. Cheers, KSat

Hello fellow Kerbonauts, I will post here some comments about the plannend stuff. But although I have some knowledge in spaceflight and spaceengineering, I might get some things room or have overseen some details. Spinning to produce gravity: You will need to spin to create 1g on the outer edge of the spacegraft for 1U: 14 rad/s or 2.23 1/s for 3U: 8 rad/s or 1.285 1/s How are you going to generate the momentum for the spin? Reactionwheels certainly can help but are comparable heavy and use a lot of volume. Magnetorquers are pretty weak but might be able to do it, you need attitude sensors and controllers to power the magnetorquers at the right time to spin up. Cold gas thrusters. Easy to do, but as far as I know only low pressurized gas tanks with inert non toxic gas is allowed, which limits the ÃŽâ€v. Sensors: Cameras - cool , small and cheap , if you have the bandwidth to transmit the pictures/videos best you can do. Temperature - mandatory. It does not matter what experiment you are planning you need Temperatures sensors. You have electric components producing heat and the sun from one side providing substantial heat flow. When you are near earth the temperature of the earth adds up to the heat flow as the reflection from sunlight of the earth onto the spacecraft. So at every moment you need to make sure that your spacecraftcomponents are within the acceptable temperature range. Humidity - should be easy , as every cheap thermometer contains one. Light - is already done with camera Oxygen - should be of the shelf I have some questions/concerns how to realize the experiment. How do you think to sustain the pressure of your experiment? You will probably have a lot of probes and stuff going in and out, making it leaky. So some atmosphere will get lost, replacing it is tricky as only low pressure tanks with inert gas (not oxygen, better CO2) is allowed. "No pressure vessels over 1.2 standard atmosphere shall be permitted. " How do you make sure your experiment set up survives till orbit? I envision a containment with soil as the ground and seed in the soil that are able to break trough the foil(?) into the pressurized part of the containment. If so how to make sure that the g-load during launch will not rupture said foil, or spread the soil all over? You probably already have seen this document, but to be sure: Cubesat Requirements http://cubesat.calpoly.edu/images/developers/cds_rev13_final.pdf Cheers, KSat

Hello fellow Kerbonauts, yes we might be able to help you. Time is limited to everyone of us, so we might not be able to put that much effort into your project, but I like to overlook your mission plan for feasibility. I also have access to a number of space flight experts that are able to answer trickier questions. Can somebody be so kind and give me a summary of what you are exactly planning to do? As the 66 pages are a lot of segmented reading... Another project done by my team and other european students was the european student moon orbiter. The project survived a PDR before it was cancelled by ESA. Cheers, KSat

Hello to the university of maryland. Do you plan to make some KSP parts from your projects as well? If so I might be able to lead you the way from CATIA models to KSP.

Yes, I could do that. Do you have any in particular in mind? It might be feasible to do the pumpkin cube sat structures. http://www.cubesatshop.com/index.php?option=com_virtuemart&Itemid=66&vmcchk=1&Itemid=66 It might be important to note ... the 4 U Cubesat from video 2 is scale 10:1 so they fit nicely to the kerbal parts. If you are intrested in them I could make the parts.

Hello fellow Kerbonauts, I made two videos (and the KSP parts) for missions that are plannend around my university. First the SHEFEXIII Mission. The unique shape is developed to minimize costs and complexity of reentry vehicles. The surfaces are made of C/SiC ceramics. The temperature of the tips will rise to 4-5000K durign reentry, therefore active cooling measures have to be used. In reality gas is pushed to tiny cracks of the ceramic to cool the tips. After reentry only the tips need to be replaced, making it a very cheap heat shield. The 5min video you can see here: Second the MIRKA2 Mission. A cubesat satellite mission currently developed by the KSat student team and the Institute of Space Systems of University of Stuttgart. The cubesat consist of two segments. A 30cm long deorbit module, that is propelled by a experimental pulsed plasma engine, that is developed by the Institute of Space Systems. The engine is used to deorbit the satellite from the ISS orbit, where it is planned to be launched. The second segment is the reentry capsule (micro reentry capsule 2 -> MIRKA2), that carries a experimental heat shield. It gets ejected at an orbit altitude of 125 km. It will then collect data during reentry about the ablation behavior and transmit said data before exzessive litho/aquabraking occurs. The 5min mission overview video you can see here: If you have any questions about the science or how the parts were created for KSP do not hesitate to ask. Cheers, KSat

Hello Kerbonauts, we are aerospace students from the university of stuttgart. KSat is german for "Studentische Kleinsatellitengruppe Uni Stuttgart", which translates to small satellite group of the university of Stuttgart. KSP is very nice to get a feeling for orbit mechanics, abroad from the pure mathematical formulations, and it might be addictive to live your own megalomania. We already did some new parts for KSP from the institute of space systems and the DLR in stuttgart. I will post further details in the add-on section. We have already some 5min Videos of our new parts online. MIRKA2 - Cubesat Reentry Mission - our current project SHEFEX III - https://en.wikipedia.org/wiki/Sharp_Edge_Flight_Experiment If anybody has questions please do not hestiate to ask. Cheers, KSat