“One things that binds us all together is the love of aeronautics and space exploration. It is as true today as it was 100 years ago. The University of Michigan started the first collegiate aeronautics program in the United States in 1914. Since then, the Department has graduated more than 6,000 aeronautical and aerospace engineers. Our graduate program ranks No. 1 among public institutions and our undergraduate program ranks No. 3 in the nation by U.S. News for 2013.”
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Results of the analysis of the RAX-1 and RAX-2 attitude determination system have recently been published.
John C. Springmann, James W. Cutler, Flight results of a low-cost attitude determination system, Acta Astronautica, Volume 99, June–July 2014, Pages 201-214, ISSN 0094-5765, http://dx.doi.org/10.1016/j.actaastro.2014.02.026.
Figure 12 from the paper. Attitude determination accuracy of RAX-2 data collected on December 9, 2011 16:00:00 UT using the 6-state MEKF without an albedo model. Albedo is treated as noise in the filter. (a) 1–σ bounds and (b) approximate total accuracy.
The paper presents flight results of the attitude determination system (ADS) flown on the Radio Aurora Explorer (RAX) satellites, RAX-1 and RAX-2, which are CubeSats developed to study space weather. The ADS sensors include commercial-off-the-shelf magnetometers, coarse sun sensors (photodiodes), and a MEMs rate gyroscope. A multiplicative extended Kalman filter is used for attitude estimation. On-orbit calibration was developed and applied to compensate for sensor and alignment errors, and attitude determination accuracies of 0.5° 1–σ have been demonstrated on-orbit. The approach of using low-cost sensors in conjunction with on-orbit calibration, which mitigates the need for pre-flight calibration and high-tolerance alignment during spacecraft assembly, reduces the time and cost associated with the subsystem development, and provides a low-cost solution for modest attitude determination requirements. Although the flight results presented in this paper are from a specific mission, the methods used and lessons learned can be used to maximize the performance of the ADS of any vehicle while minimizing the pre-flight calibration and alignment requirements.
Project Strato flew their team’s 10th flight this past weekend with a successful launch and recovery. Unfortunately, we learned a hard lesson about proper radio packet configuration. We apologize to the APRS users for our excessive network traffic during the flight on 16 March 2014.
Our balloon flew two trackers, a Kenwood TH-D72 handheld radio and a modified MicroTrak tracker. These tracking devices were intended for two purposes: tracking the payload during flight as well as deriving altitude, ascent rate and descent rate data from the received packets. These devices were configured with settings similar to the defaults which were designed for mobile terrestrial use. However, our use of these settings while airborne, specifically the use of digirepeating paths and transmission rate, caused unreasonable congestion on the 144.390 MHz public use frequency. We apologize to the many users of this wonderful service who were impacted by our unintentional misuse of the network.
We thank a couple HAMs, Stephen Smith WA8LMF and Dave Dobbins K7GPS in particular, for their help in identifying the problem and letting us to know to fix. Lynn W. Deffenbaugh posted interesting plots of packets received and their distances, see below. Based on their feedback, our future flights will have properly configured multi hop settings and transmission rates. There was also some pretty impressive flaming that occured on APRS related lists. Again, we apologize for the congestion and will not repeat.
Red lines represent direct reception. Green are multipath packets. It’s quite clear how far the packets from the flights reached.
Fortunately, the rest of the flight was a success. As a training mission, students gained valuable hands on experience in developing and flying. They set an internal team altitude record of greater than 104,000 feet. Their inertial measurement unit measured accelerations and rotations for flight dynamics modeling. Flight operations went well despite the wind and cold. Recovery was good.
Launch, Strato Flight #10.
We look forward to future flights that will continue to flight test new technologies and train the next generation of engineers. We appreciate the help and advise from our neighbors and mentors. Thanks again!
Congratulations to the MCubed-2 team for the first successful image of Earth. Below, there is a fantastic, snow-covered picture of Lake Superior, the upper peninsula of Michigan, Wisconsin, Minnesota, and Canada. The deep freeze of the Midwest is clearly visible.
MC2 captured a snow covered Midwest today, her first photo downloaded from the mission.
Prof. Washabaugh, on seeing the picture, asked if the camera was black and white. We all laughed saying, “Nope, that’s just space and snow!”
This photo is for Kiko and that original MCubed-1 team. Here is your space selfie. We’ll work on some SoCal shots later.
Go Blue!
Thanks to Ed Kudzia, BSAE ’75, for taking MXL patches global! Check out Ed putting up patches at the Cocoa Beach Brewing Company near Kennedy Space Center and another patch at the Mayflower Pub in Ottawa. Go Blue!
UMich alum, Ed Kudzia BSAE ’75, places an MCubed-1 patch at the Cocoa Beach Brewing Company.
MC1 @ the Mayflower Pub
MC1 @ the Mayflower Pub