ISU Rockoon Project
The ISU Rockoon Project is a joint venture between the Iowa State Space Society and the Space Systems and Controls Laboratory at Iowa State University. The project is seeking to develop a rockoon to fulfill the guidelines of the SEDS Innovation Challenge and further the field of balloon assisted rocket launch. Real world rockoon applications include the study of the upper atmosphere and the delivery of suborbital payloads at a cost much reduced from that of a ground launch. Major altitude gains can be made based on the much reduced density of the air in the atmosphere at 75,000+ feet and the resulting reduction of drag on the rocket during flight.
- (Spring 08) We have secured approximately half of our estimated funding needed to complete the project. This funding came from the Iowa State Engineering Student Council through the Iowa State AIAA. We are currently working to seek the rest of the funding needed, but will be refining our plans in the meantime using what we currently have.
- (Summer 08) Major work has been progressing on a variety of fronts towards both the estimation of what rocket motors will achieve the greatest altitude gain when starting from ~100,000ft. and the testing of our custom high-altitude igniters.
- (Fall 08) The test flight for the custom igniters provided a great deal of information about conditions at the launch altitude and gave us insight into the flight of a balloon payload despite failure of the logic boards which prevented the igniters form firing properly.
- (Winter 08-09) Work has begun on the tracking and altitude measurement electronics for the rocket, as well as the outer structure of the rockoon launch platform. Progress has also been made in preparation for a teathered flight of the launch platform.
- (Spring 09) Extensive SolidWorks modeling of the rockoon has begun, with the intension of optimizing the geometry, material selection and construction of the launch platform. We are also weighing the possibility if CFD modeling of the rocket and nozzle to extend overall height and facilitate an efficient, consistent rocket launch.
- (Summer 09) With a somewhat definite launch date during Spring and Summer 2010, we are finalizing our plan for the competition-ready rockoon with a detail oriented design approach. Though we were too late to get an order of parts in Spring 2009, we working to re-secure funding through the next fiscal year and making a "shopping list" to make future purchases go smoothly. ISU Rockoon needs more team members, and we are looking for dedicated students who want to be part of a group project, so please see the contact section to get more information!
- (Fall-Spring 09) Now that the 2009-2010 school year has started, recruitment efforts have gone into full swing. ISU Rockoon has sought new members through the Iowa State Open Lab program, as well as at the Engineeirng ClubFest. In addition, a memorandum has been drafted to better define the roles of the ISSS and SSCl in the ISU Rockoon project, as well as provide a fairly detailed breakdown of the tasks at hand. Progress on the tracking package has been furthered as the various components are brought together and assembled. We are also in the process of securing funding for the current fiscal year from various university groups in order to cover rocket parts as well as HABET test flights. The date of the launch has also been solidified, as AeroPac has agreed to run the logistics of the SEDS rockoon launch. The current launch date will be in August 2010, in Black Rock Nevada.
- (Fall 10) After successful initial talks with AeroPac and the remaining SEDS group looking to launch a rockoon (based at the University of Arizona), communication with AeroPac was lost and a decision was made to investigate the launch of the rockoon within Iowa to save the transportation costs that would be involved in a trip to Nevada. Also, on a administrative basis, the project is now formally a SSCL-run project. As a SSCL project group, the rockoon team is currently seeking funding from multiple sources to commence ground and air flight-testing of the rocket within Iowa in Fall 2010 to be followed by experimentation with scientific payloads in Spring 2011. The rocket is currently in the final phases of construction, while the launch rail and launch electronics box have also been constructed. After the completion of HES 2.0 and BERT 2.0 electronics by the SSCL (next generation data and recovery avionics), those packages will be implemented into the rocket electronics bay and the launch electronics and we will be ready to fly!
In order to facilitate a rocket launch at 75,000+ feet, igniters have been formulated which will fire consistently and with enough energy to lite an ammonium perchlorate solid rocket motor in the subzero temperature, low density air found at that altitude. These igniters create an oxidation which is stable in these conditions and can be easily made and shaped into the correct dimensions. Unfortunately the HABET flight used to test these igniters in flight conditions suffered an electronics failure, and was unable to send the command to ignite the samples.
The composition of the igniter compound allows for the creation of shaped plugs which fit into a standard high-powered rocket engine. The formula of the igniter chemicals has also been stabilized so as to avoid explosive combustion and favor a steady burn. These igniters are just one example of the multi-discipline approach used by the rockoon team to create a polished finished product.
A second HABET-based igniter test flight is scheduled for November 7, and will make a second attempt to ignite the mixture. The electronics configuration of the new flight (L-112B) will be similar to the previous attempt, and include video equipment as well as thermocouples attached to data loggers to get video of the ignition as well as temperature readings. Other ideas for guaranteeing ignition success include a burst plug in the nozzle of the rocket motor to maintain ambient pressure in the ignition chamber, and considerations for thermal effects of the cold environment
Construction has begun the rockoon launch platform as well as the electronics systems both onboard the rocket and to control the launch from a box on the balloon. The current plan is to construct a rail-based launch system and use a small rocket with inexpensive motors to do various ground and tethered flight tests before launching full scale in a test of all of the systems.
The launch platform will extend the current capabilities if a HABET payload to include active ground communication and a structure from which a rocket may be launched. Competition rules restrict the rocket to be launched within 15 degrees of vertical, though the rocket must fly at an angle of between 7 and 8 degrees so as to not collide with the balloon(s) in flight. An angled launch like this requires that the rocket be stable in low-atmosphere conditions, so many aerodynamics considerations are currently being made to ensure a successful flight.
A triangle shaped launch configuration has been assembled to test the feasibility of an angled launch on a scaled down rocket. The launch rail will require am extension which attaches above the top of the triangle, though length will hopefully be limited by achievable launch velocities. The weight savings from using a shorter launch rail will allow the rockoon to fly higher using only the balloon. A simpler suspended design is also under consideration.
The rocket configuration chosen for the flight will incorporate high quality carbon fiber parts, including a filament wound airframe and highly rigid composite fins for high strength and low weight. According to recent simulations, the rocket may achieve in excess of 140,000 feet in total altitude from a maximum balloon carried height of around 90,000 feet. This rockoon will allow for such launches at a cost of less than $1000 per flight.
Work has also begun on an integrated package which will incorporate all of the parts required for radio-based GPS tracking for the rocket which will allow for a altitude confirmation as well as following of the rocket on its return to the ground. The GPS package will include a secondary radio tracker for additional recovery support.
Since there is not an accurate high-altitude rocket simulation code available, a custom MATLAB script has been written which uses a mechanics approach to chart relevant variables. This code will hopefully assist in finding a suitable combination of rocket hardware and achieve the highest possible altitude gain. The code takes in data about the thrust properties of a motor and properties of a rocket design and generates plots of height, velocity, acceleration, etc. for the rocket for all phases of ascent. This code is an ongoing project, with a goal of narrowing down the possible flight hardware combinations through continual program improvements.
If you are interested in the ISU Rockoon Project, feel free to contact us. Though rockoon activities quieted down somewhat last semester, we are hoping to give it new life through promotion and a campaign to raise interest in SSCL-based projects.
You can see more of where we are with the ISU Rockoon Project RIGHT NOW over at our working website : https://sites.google.com/site/isurockoon/.
John Gottsacker - firstname.lastname@example.org
If you would like to be added to the rockoon email list, please let us know!