GATEWAY TO SPACE SPRING 2006 DESIGN DOCUMENT

Transcription

1 Colorado Space Grant Consortium GATEWAY TO SPACE SPRING 2006 DESIGN DOCUMENT Team Name: A.E.M.B.L. Project Name: Trojan Horse Written by: Nick Bradley, Matt Lenda, Emil Reinovsky, Spencer Sator, Kevin Weber 04/18/06 Revision C

2 Revision Log Revision Description Date A Conceptual Design Review 03/02/06 B Preliminary Design Review 03/23/06 C Critical Design Review 04/13/06 D Analysis and Final Report 05/02/06 Page 2 of 17

3 Table of Contents 1.0 Mission Overview Mission Statement Overview of Mission Design Management Team Organization Team Schedule Budget Test Plans Expected Results Launch Day Program Team AEMBL members and background notes: Nick Bradley astrobradley@gmail.com, Freshman in aerospace. Power and wiring. Technical knowledge and experience with hands-on construction. Matt Lenda Matthew.Lenda@colorado.edu, Freshman in aerospace. Computer knowledge, technical expertise. Emil Reinovsky Emil.Reinovsky@colorado.edu, Freshman in aerospace. Structures. Knowledge of SolidWorks, and machining. Spencer Sator xakota@gmail.com, Senior in astrophysics. Team leader. Experience with circuits, GPS systems, physics, and high-tech scientific instruments. Kevin Weber Kevin.Weber@colorado.edu, Freshman in aerospace. GPS Liaison. GPS handling and data engineer. Computer strengths and GPS functionality knowledge. Page 3 of 17

4 1.0 Mission Overview 1.1 Mission Statement The purpose of our BalloonSat is to accommodate, carry and protect an advanced GPS unit and associated hardware designed and developed by CU graduate student Stephan Esterhuizen, to make sure all data is retrieved successfully, and to ensure that the computer unit does not sustain any significant damage during flight. 1.2 Overview of Mission The primary objective of our BalloonSat box will be to carry Mr. Esterhuizen s GPS unit. The secondary mission is to also fit in our HOBO data logger, heater, and battery system. Carrying the GPS unit is of great interest to our group, as our original mission objective was to launch a commercially-available GPS unit to measure atmospheric air velocity (including the jet stream, which peaks around nine kilometers) and air temperature as a function of altitude. To achieve our mission objectives, we must develop a structure that will be able to carry Mr. Esterhuizen s larger, more expensive GPS computer and land with all systems intact. This mission will enable us to conduct the experiments we had originally wanted to carry out, as well as participate in an exciting project utilizing cutting-edge ideas and technology. We will still include several secondary systems, such as thermometer, HOBO data logger, camera, batteries, and heater, as is required for all teams in the class. Flying at altitudes as high as 30 kilometers, Mr. Esterhuizen s GPS unit will be subject to previously unencountered environmental extremes. A flight through such a hostile environment represents an ideal proving ground for the durability, resilience, and functionality of the GPS unit. At 30 kilometers above Earth, issues such as low atmospheric pressure, extreme temperatures, and condensation become major concerns for sophisticated electronics and need to be addressed when designing the BalloonSat. We are working closely with Mr. Esterhuizen to create a BalloonSat that will mitigate any environmental factors which have potential to affect the operation of the GPS unit as it explores previously uncharted territory. Our end goal is to eliminate any possibility of unforeseen elements degrading the quality or quantity of data gathered. If successful, Mr. Esterhuizen s GPS will record information regarding wind currents (our original science goal) as well as providing a critical step toward the implementation of the concept of GPS reflections and bistatics in practical applications (such as remote sensing, military intelligence, passive communication and navigation). Additionally, with the inclusion of the HOBO data logger on this mission, we will be able to collect data on temperature variations at different altitudes, as we had originally envisioned. Obviously, flying this new GPS is not without complications. We have had to consider a number of risks, such as the compromised component functions due to low air pressure and temperature and the potential for overheating, as the CPU cooling fan relies on convection, which doesn t occur in environments without air. These issues have been resolved in the Page 4 of 17

5 design and testing phases and present no critical obstacle to the flight plan. We even went so far as to contact LASP and secure the use of a cryogenic vacuum chamber in which to test our module, but decided such a test was unnecessary. Interfacing various elements of this BalloonSat, as well as connecting with the other GPS team s BalloonSat are discussed briefly below. During the past month, various specifications of Stephan s computer were obtained which allowed us to begin the construction of the box. Specific implementations are discussed below. 2.0 Design There have not been any major changes in design since the previous revision. The one significant change to the design has come after we convinced Stephan to fly two-8gb USB flash drives to store his data. He had originally wanted to fly a laptop hard drive. However, this presented several logistical hurdles including pressurization, weight, bulk, and condensation that have all been eliminated by using flash drives. The rest of the design of our BalloonSat is relatively straightforward. We eliminated our previous plans to fly an additional camera to image the horizon, mirrors to image both the ground and balloon, and an altimeter all were eliminated to meet stringent mass requirements. Despite the pairing-down of our BalloonSat in weight and complexity, we still meet all requirements set forth in the RFP. We will measure and record temperature (with a dual thermometer and HOBO), provide internal heat and power, image the ground with an optical camera, gather ascent and descent rates (by contacting the balloon operator after flight) and fly an additional science experiment (we will use Mr. Esterhuizen s GPS data to measure wind velocity as a function of elevation, as we originally proposed), all while remaining well under the $300 cost target (in fact, we anticipate a cost of zero for our BalloonSat). We have incorporated external switches and timing circuits that will make launch day operations as simple as possible. We currently have a BalloonSat designed to weigh as little as possible while virtually guaranteeing safe return of Mr. Esterhuizen s data. For details on the physical layout of our BalloonSat and total mass, as well as a functional block diagram, please refer to the following sections. Currently, we feel as though our design is adequate to keep the instrumentation well above the 0 C necessary for smooth computer and solid-state operation (read about our cold test results below). Additionally, with the switch to flash drives, all the hardware on our BalloonSat is more than able to handle the accelerations that will be encountered during flight, balloon pop/release, parachute deployment, descent and landing. We foresee no issues relating to temperature, pressure, condensation or motion compromising this flight. A complete list of the components involved with this BalloonSat mission are listed with their corresponding weights in Section 4.0 of this document. Page 5 of 17

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8 12V Batteries Switch 9V Batteries Switch Data Stream Computer Timer Heater Switch Camera 1 Camera 2 Power for computer USB Hub HOBO Flash Memory Temperature sensor Internal Temperature sensor External Page 8 of 17

9 Subsystems and Overall System Requirements As seen in the functional block diagram above, we have external switches mounted on the exterior of our BalloonSat for the camera/timing circuit subsystem. The external switch will ensure quick and easy launch-day operation. As mentioned above, we abandoned earlier design plans which included a second camera, as well as a mirror system, in order to meet size and mass targets. Unlike other groups, we will not be flying a separate heating unit. The heater and associated batteries were removed from our design after cold tests were conducted. See section 5.0 below for more information. The HOBO unit is a self-powered, self-sufficient subsystem. Other than the two temperature probes, the HOBO will not interface directly with any other system on the BalloonSat. Finally, we have the CPU subsystem. It is independent of all other subsystems it has its own power, its own memory storage, and its own heat requirements. The battery for the CPU will provide sufficient heat for our other subsystems (camera, HOBO). Other than the exclusion of a heater and batteries, the overall system requirements have not drastically changed since Rev B was submitted. Stephan s battery for his CPU will provide sufficient power for 3 hours of CPU operation (as confirmed during cold tests), and his USB flash drives will be able to uphold the data stream that would originally have been managed by the hard disk, while providing more than adequate heat for smooth operations. 3.0 Management 3.1 Team Organization We have received assurances from Mr. Esterhuizen that we will have data back from his GPS experiment a few days after launch. We have also appointed a GPS liaison who will coordinate between our group, the other GPS group, Mr. Esterhuizen, and Professor Koehler. While we determined that regular meetings among all parties is unnecessary, we felt that designating a single person to act as a communication intermediary would streamline interaction among groups. Page 9 of 17

10 Member Name Design Duties Construction Duties Communication Duties Recording Duties Spencer Sator Instrumentation fit and box design Insulation, wiring, circuitry, foamcore alterations Team Leader Co-author for revisions Kevin Weber GPS computer and battery integration GPS computer and battery system integration GPS Liaison Org charts, PowerPoint presentation creator Emil Reinovsky Overall group leader for BalloonSat integration System integration, general overseer and director, soldering Secondary GPS liaison duties All technical diagrams Matt Lenda Camera, timing circuit integration Foamcore fitting, circuitry, switches, power tools Secondary team leader duties Co-Author for revisions Nick Bradley Power, heat, HOBO integration Power, wiring, heat, soldering, foamcore cutting SpaceGrant Liaison Principal editor for revisions and presentations 3.2 Team Schedule Below is a summary of our group activities since we received initial feedback from our original RFP and began detailed recordkeeping. Our upcoming group activities are previewed as well: March 3: Received finalized system specs from Mr. Esterhuizen. The mass turned out to be significantly less than what we had been anticipating, allowing us additional leeway when putting the BalloonSat together. The computer unit had only two necessary interface points meaning that box construction would be simple and keeping maximum insulation would be easy. The battery is a bit on the heavy side, but very compact considering the power it produces. Small battery means we can make our BalloonSat smaller still (and presumably stronger). March 5: Team meeting at 7:00 p.m. We worked to finalize design ideas particularly how to determine how USB and tether will need to run to other GPS team box. After receiving the statistics this task was rather easy. However, we still needed to coordinate with the other BalloonSat group to make sure our USB routing plans were compatible. March 5: Kevin will contacted the other GPS team to agree upon a suitable USB and tether arrangement for both boxes and reported back to Emil, who revised the design. Page 10 of 17

11 The plan is now very solid: we know the masses, compatibility and overall design of both GPS groups. March 7: Emil finished all technical design of our entire BalloonSat and submitted it to the other group members for review and oversight. Through communication, we provided only minor feedback and the design was quickly finalized. March 8-10: For two days, Emil and Nick acquired all the necessary hardware and software for the current design. We got materials in class, from Brian and at SpaceGrant. Though we later needed a few odds and ends, we had nearly everything we needed for construction of the BalloonSat on March 10. March 12: Team meeting. This was a short, organizational meeting which was spent discussing plans and schedule for construction. We agreed upon an all-day building session on March 19 at SpaceGrant. We decided this approach would be more efficient than getting together several times for shorter sessions. Getting five busy people together anytime is logistically difficult, but doing so several times would have been impossible. We also chose SpaceGrant as our location so that we would have access to any necessary tools and hardware. March 19: Construction and integration of BaloonSat and all subsystems. We did virtually everything this day: cut foamcore, cut insulation, mounted switches, tested wiring and circuits. We even conducted two drop tests (results are discussed elsewhere in this document). The drop test has a few negative effects. We had some wiring that came loose from the camera. There was also a flaw in the timing circuit. We also discussed strategies for REV B. Several group members were to work on different sections. Matt and Spencer were to compile all information and put it all into a cohesive, complete document. March 20: Matt and Emil soldered the components damage in drop test and conducted a second series of drop tests, which were successful. Spencer evaluated all components in the BalloonSat for additional weaknesses and re-soldered several components. We were prepared for the cold test at this point. However, in order to run a realistic test, we had to be wired into the other GPS team s BalloonSat. Due to some delays on Stephan s end, they were a little behind us. March 21: We met briefly with the other GPS team during team time and discussed cold testing. We pressured them to try to be ready before spring break. They decided that they would try to be ready before spring break, but will still trying to get components from Stephan. March 20-22: Team worked on Rev B mainly via . We saw some substantial revisions to several parts of the design, plans, logistics and other aspects of the document. Matt submitted Rev B to Chris via . Page 11 of 17

12 March 23: More discussion with the other GPS team. Both teams agreed that cold testing will have to take place after spring break. March 23: After several days of contact among members and a great deal of work from Kevin, the group presentation was ready and in great shape. Only four of the team s five members were able to make it, however. Spencer had to tend to family issues and had to leave town the previous day (both Chris and the other teammates were alerted to this previously). The presentation was fairly straightforward and went smoothly. March 25-April 2: Spring Break April 4: We skipped our normal team meeting this week, as some people were still trickling in from vacation. But we were in contact from Sunday through Tuesday regarding potential system performance, cold testing, faulty timing circuits, and other issues. After class on Tuesday, we further discussed these plans, and made arrangements with the other GPS team for cold testing. April 8: Cold testing. Both GPS teams and Stephan met at SpaceGrant at 9 a.m. After several last-minute adjustments and some hiccups, we put everything into a large cooler with dry ice. The test was a resounding success for both teams. After three hours in the cooler, the internal components of our BalloonSat were hot to the touch (the other team had a temperature slightly above freezing still good results). We did, however, encounter two problems: our HOBO and heater both malfunctioned. However, neither glitch was a serious issue. The HOBO wasn t vital, because it was simply there to confirm the internal temperature remained above freezing. Since the box was hot when it came out, we have informally confirmed this. And since the other GPS group had a properly-functioning HOBO, we were able to ascertain the temperature in the cooler. Meanwhile, the heater we had included in our BalloonSat was clearly unnecessary after witnessing the excess heat generated by Stephan s computer. April 9: Team meeting. This was a relatively fast meeting. After the cold test we had only a few issues left t address before final flight: fixing the broken timing circuit, getting a new HOBO, and arranging for a whip-test. Emil volunteered to take care of the circuit, and whip test arrangements were never agreed upon. We decided to wait for another meeting. We had also previously contacted Brian for a new HOBO and were awaiting a response. We also made plans to revise this document. Spencer, Emil and Kevin all had specific sections assigned to revise, while all group members agreed to look all sections over and provide feedback via . April 10-13: Feedback process on Revision C. Feedback was provided both through and among group members before and after class. April 13: Turned in SpaceGrant Design Expo form. Page 12 of 17

13 April 15: Conducted successful acceleration/whip tests on the BalloonSat. These tests proved totally successful and uncovered no design or operational flaws. The tests consisted of both linear and circular acceleration. For linear acceleration, we simply stood on a platform and dropped the BalloonSat on a string (with mass simulator) and let the string jerk the BalloonSat to a stop. The circular test involved swinging the box around like a lasso above our heads for several revolutions. All systems were fully operational after these tests. April 16: Team meeting. This meeting will have to be very comprehensive. We need to ensure that all systems are fully operational and all bugs have been worked out. If necessary, we will conduct a whip test. However, after several drop tests, we feel as though this may be unnecessary. We will discuss this on Sunday. We will also discuss launch-day logistics (i.e.: who will drive, who can stay all day, who will be responsible for flipping the switches, how we plan to recover the BalloonSat, etc). This will probably be our longest and most methodical meeting of the semester. We have agreed to set aside the evening of Tuesday, April 18 to take care of anything that may crop up. Hopefully we will have no issues. We will also need to contact Stephan to request that he show up for the upcoming weigh-in with his computer in hand. April 18: Team time in class. Any and all unresolved issues left over from Sunday s meeting will be addressed during class. We will also contact Stephan and the other GPS team this day. We anticipate having all our plans finalized by this point and will be able to coordinate with everybody else for logistics. By the end of the day, we should be fully ready for launch. April 20: Class presentations. We will have agreed via by this point who will discuss what part of the BalloonSat. This will be our final pre-launch presentation to the class. April 21: We will bring the BalloonSat to Chris office for weigh in. We will also set the timer for the HOBO data logger to switch on at launch time. We should be fully ready to launch at this point! April 22: Launch Day! The launch day schedule and events are discussed elsewhere in this document. April 23: Team meeting. We will contact Stephan and request the flight data. Stephan has assured us that he can get nearly instant results relating to position. We will need this data by April 25. April 25: We will begin discussion here who will do what in relation to final reports and presentations. Generally, Kevin has taken care of the presentation, while Spencer and Matt compile the documents. Nick provides a tremendous amount of feedback in both areas. Since this formula has worked well for us in the past we anticipate little change. We will have to have all the data from Stephan by this date and all assignments divvied up in order to ensure completion of presentation and reports in time. Page 13 of 17

14 April 25-April 29: Compile and comment on all progress made on the progress we have made on the final report and presentation. We MUST be done with these projects by April 29. April 29: ITLL Expo All group members will need to be present. April 30: Team meeting. Here we will discuss and practice our final presentation. We will also make any last-minute adjustments to our final document. This will enable us to be ready for the first presentation, if we are to go that day. Kevin has been in charge of producing the PowerPoint presentations for the group, so he ll arrive with a presentation already completed, pending comments and suggestions from the other group members. May 2 or 4: Presentation. May 5: Final Exam (we ll all ace it!) Launch Program: The details of the computer system operations will be left to Mr. Esterhuizen. He will be present on launch day to boot up his system and ensure that all his components are connected and working correctly. Our group will be charged with secondary tasks, such as switching on the imaging camera, will also occur as close to launch as possible, because of limitations in battery life and data storage capacity. We have mounted an external switch on the flight box that runs these secondary systems making this step quick and easy. Summary of Launch Day events: We will meet and leave Boulder by 5:15 a.m. on April 22, The team will then travel to the launch location in Windsor (number of cars to be determined), approximately one hour northeast of Boulder. At the launch site, our BalloonSat will be attached to a tether, which is in turn attached to a weather balloon. At 7 a.m., the inflated balloon will be launched, bringing our instrument package as high as 30 km during a 90-minute ascent. We will follow a lead vehicle that will track the balloon using navigation systems. All members of the group who have daytime availability on April 22 will be in our chase vehicle that will follow the balloon s path on the ground. Payload landing is anticipated to be around two hours after launch 9 a.m. We will recover our instrument package, give a cursory evaluation of the health of the payload, pose for pictures, and return to Boulder for subsequent data analysis and return of the (hopefully still-in tact) GPS unit to Stephan Esterhuizen. 4.0 Budget Complete list of components provided by Mr. Esterhuizen SBC + Heatsink + USB Stick + Power (DC/DC) 500g Battery (provides power for ~3.5 hours) 457g Cables 45g Page 14 of 17

15 Enclosure 250g TOTAL 1257g COST $0 Complete list of components provided by team AEMBL: HOBO 30g $0 12V Batteries 30g $0 Timing circuit 30g $0 Camera 200g $0 Insulation 100g $0 Box (foamcore, aluminum tape) 70g $0 Switches and wiring 50g $0 Thermometer probes 50g $0 TOTAL 560g $0 GRAND TOTAL, ENTIRE BALLOONSAT: 1807 grams 5.0 Test Plans Drop Test: Implemented to ensure strength of structure of BalloonSat With all of our components secured inside our box, we taped it up and conducted a series of drop tests March 19 and 20 (see schedule above for details). We kicked the BalloonSat with moderate force down a long (7- meter) staircase. The damage to the box was minor: a slightly dented edge and roughed-up corners. These damages represent only minor issues and were purely cosmetic in nature they threatened the overall operations of the BalloonSat in no way. When dropping any object made of foamcore down a flight of stairs (or from the upper atmosphere) damage of this nature is expected. After the kick test, we found a 3-meter balcony and dropped the box straight down to the floor. In this test, there was more significant damage. There was a wire that detached from a battery pack, and the relay circuit. To address these issues we have replaced the relay circuit and have replaced the wire, making sure that all connections were secure. We also decided to undertake an additional visual evaluation of the strength and security of all electrical connections. During these tests, there was some worry as to whether or not the custom-cut slot for the camera would suppress the movement of the camera during the bumps and jolts of the test. We discovered that this cut was perfect for the camera, as it did not budge in any direction during the tests. This test was, therefore, successful in pointing out weaknesses and Page 15 of 17

16 confirming system design strengths. All necessary issues raised in testing have been dealt with. Cold Test: Implemented to ensure insulation/temperature capabilities meet system requirements The cold test was conducted Saturday, April 8. The procedure was fairly straightforward: our BalloonSat was loaded with all of Stephan's hardware and all of our operational systems along with the other GPS BalloonSat into a cooler containing dry ice. The temperature in the cooler was approximately what our BalloonSat will encounter in flight. The cold test was a resounding success. Stephan's CPU and battery created an unanticipated amount of heat. In fact, the internal components of our BalloonSat were hot to the touch after three hours in a dry ice cooler--pretty remarkable considering the other GPS BalloonSat team had difficulty staying above freezing. However, we were unable to ascertain exact figures for internal temperature, as we had a HOBO failure that prevented data gathering and storage. We are currently discussing the need to conduct another cold test to gain this information, but are awaiting advice from Chris on whether it is necessary. Another interesting finding after cold tests were conducted was that our internal heater actually failed. All the heat in the box was created by Stephan's computer and battery. This means that we are now able to exclude the heater and associated batteries from our final design--saving a small amount of weight. Besides the HOBO and heater failures, all systems performed extremely well during cold testing and we anticipate no cold-related problems on launch day. Whip Test: Implemented to ensure BalloonSat can survive whipping motion after burst This test was successfully conducted on April 15. We accelerated our BalloonSat with various orientations in both circular and straight paths. The whip test was conducted to ensure the structural integrity of the BalloonSat, as well as to test the internal components in the harsh acceleration environment that It will likely encounter during takeoff, flight, balloon burst, descent and landing. As mentioned above in the team schedule, all whip tests went exceeding well. All BalloonSat components functioned flawlessly during and after all tests. 6.0 Expected Results Due to the major changes in data storage capabilities of our BalloonSat, we expect the design to me much more reliable. The data that will be stored from Stephan s CPU will be much more secure with the USB drives. Also, his desire to test his device at high altitudes will not be sacrificed all that must be done is to tell each USB drive to turn on at a certain time. That way, blocks of data from different altitudes can be recovered as opposed to a giant block collected below 15,000-20,000 feet (about m). The pre-launch process has become simplified to a much better degree than expected. The switch for the timer circuit is accessible on the outside of the box and are secured very tightly in place. Also, one flap is left open for Stephan to access and activate his CPU so data can be Page 16 of 17

17 collected. The data Stephan will receive should directly reflect the abilities of his GPS unit and due to the new data storage implementations, we are confident that it will prove itself as a reliable device. As for our temperature logging on our HOBO, we expect that our temperature-vs.- altitude pattern will display the same patterns as those that other groups will obtain. There are no complications with using the HOBO, and the probes are perfectly accurate for our needs. Ascent and descent rates can be obtained from other teams or calculated to approximate values based on time to reach maximum height and the ground and the estimated height at which the balloon bursts. We anticipate getting several highly detailed pictures of wind velocity, relative humidity and temperature as a function of elevation at several points through the atmosphere. We will be able to identify a general elevation range of the jetstream and the strength of the stream during flight. 7.0 Launch Day Program The launch day program is fairly straightforward and has been partially outlined elsewhere in this document. We will leave Boulder early on the 22 nd (weather permitting) and fly our BalloonSat from Windsor. Since our experiment will be attached to a different balloon from much of the rest of the class, we may end up at a different landing site particularly if one of the two balloon leaks and the payload had to be released. The logistical details of tracking our balloon (i.e. how many vehicles will chase, who will stay for the chase, how many people from Stephan s group and the other team will participate) will be worked out during the week leading up to launch. After recovery, Stephan will have access to location data stored on his memory sticks within a matter of days. This will enable us to have temperature and wind velocities tracked as a function of elevation (our original science goal) plotted and analyzed in time for final grading. Page 17 of 17