RocketSat

 

RocketSat is one of the first steps in getting students into space.  Using a sounding rocket, a team of students can launch a small payload into space.  The rocket would then fall back to earth, allowing for the payload to be retrieved.  Sending something into space presents many more design challenges than a balloon flight and gives students hands on experience they may not have otherwise gotten.  RocketSat gives undergraduate students the opportunity to design their own payload, build it, and with in a year, see it be launched.  Similar to all projects in the Colorado Space Grant Consortium, RocketSat is also a student run project.

 

The University of Colorado developed the RocketSat idea with an end goal of creating a class or workshop from a basic, easily reproducible design.  Since the start of the program, there have been four student designed, student built payloads and the first successful workshop:

 

 

RocketSat I 

 RocketSat II

  RocketSat III

 RockOn Workshop

RocketSat IV

    

     

 

 

 

 

 

 

 

RocketSat I

 

In the fall of 2005 a group of freshman and sophomore students started the first RocketSat with the intention of creating a basic system that could be easily reproduced and could eventually turn into a workshop.  On board were two basic science instruments, a Geiger counter and microwave detector.  Also, on board were a multitude of other sensors designed to take data from the flight environment including a temperature sensor, a pressure sensor, and x-y-z accelerometers.  Due to an aerodynamic anomaly, the rocket had an off nominal landing and the RocketSat payload was destroyed.  No data was recovered from this flight but it still provided a great hands on learning experience to all of the students involved.

 

The final payload was mounted to an aluminum plate for structural support. It was launched September 25, 2006 from Las Cruces, NM with Up Aerospace. The plate did not survive the flight, do to an aerodynamic anomaly, and no data was retrieved from the flight.
                        

RocketSat II

RocketSat II followed RocketSat I by trying to prove the concept that a group of students could create a working sounding rocket payload with an easily reproducible design.  Again the main goal of the project was to take data from the flight environment.  The payload included a video camera, temperature sensor, pressure sensor, accelerometers, humidity sensor, strain gauges, and a faculty sponsored GPS experiment.

 

The final payload used stacked configuration with polycarbonate plates for structural support.  Its launch date was April 28th, 2007 from Space Port America in New Mexico, once again with Up Aerospace.  The payload was returned and all data was retrieved.  The time based GPS experiment did not work as planned due to a small delay in launch, however all of the other sensors yielded interesting and useful data.

  

 

Showing stacked configuration just after completion.

An image taken during flight with the camera on board the RSII payload.

 

 

 

 

The RocketSat II payload after flight.  Although some structural damage occurred, data was able to be retrieved.

This is a sample of the data retrieved by RocketSat II.  It shows the Low Range Accelerometer data as a function of time.

 

 

 

RocketSat III

 

 

At the same time that RocketSat II was finishing up, RocketSat III started up.  RocketSat III's goal was to re-fly a lot of the sensors and hardware that RocketSat I flew.  On board was a new Geiger counter and microwave sensor.  Also updated was a new silicon pressure sensor.  Once again, the team fit everything onto a single aluminum plate that sat on top of another payload for the Microgravity Enterprise Inc.  It was launched in the night on June 27th, 2007 from the Las Cruces area.  The payload was returned in perfect condition.  The mission was deemed a complete success.

 

The RocketSat III plate sitting on top of another payload. RocketSat III was launched during the night.

 

RocketSat Workshop

 

One of the RockOn teams working on a piece of the hardware needed for their payload.

 

RocketSat I-III all were leading up to the development of the RocketSat Workshop.  The Workshop, dubbed RockOn, was designed to bring the RocketSat concept to other schools and educational programs around the nation.  RockOn was the next step in complexity in hands on how-to workshops and was led by Chris Koehler, director of the Colorado Space Grant Consortium.  Starting in the fall of 2007, preparations for RockOn began.  The workshop was organized by a group of freshman and sophomore students and Professor Chris Koehler from the University of Colorado.  The group used the same type of hardware flown on the previous RocketSat missions with a few modifications.  The final flight hardware included a Geiger counter, pressure sensor, temperature sensor and high and low precision 3-axis accelerometers.

 

Fifty-seven participants made it to the Wallops Flight Facility in Virginia to participate in the RockOn workshop. The workshop was kicked off on Sunday, June 22, 2008 with team building activities and a general overview of what would happen at the workshop. Over the next three days, teams of two to four successfully built a sounding rocket payloads measuring  temperature, pressure, counts of radiation, and accelerations in three axes. Day four consisted of site tours and the final preparation of the payloads and the rocket. On the fifth day, June 27th, 2008, the participants were able to watch their payloads soar to an altitude of 41.5 miles on a 21 foot tall Improved Orion sounding rocket. After the recovery of the payload section, all of the teams successfully got data back from their payload.  A workshop like this had never been done before in the history of NASA and there was a 100% success rate with all of the teams.

 

In addition to giving participants the required knowledge to start similar programs at their home university, Koehler also hopes that the RockSat can structure used during the RockOn workshop will serve as a structural design standard for future sounding rocket payloads. A clearly defined interface between payload and rocket is one of the more costly and toughest design challenges to a novice in the arena of space mission design.  The concept of using the same basic structure and hardware from the workshop to create a larger and more complex scientific mission was proven by the RocketSat IV team during the same launch.

 

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The RockOn kits given to each team and the canisters used for easy integration. All of the participants and staff from the RockOn Workshop just before launch. The RockOn staff.  From left to right, Eric Pahlke, Brian Sanders, Ana Ilic, Aaron Russert, Jessica (JB) Brown, Chris Koehler, Shawn Carroll, David Ferguson, Riley Pack.

 

 

                                                         

RocketSat IV

 

 

While one group of students were working on the RockOn Workshop, another small group of freshman and sophomores were working on a scientific payload.  In less than one year they were able to design, build, and launch that working scientific payload proving the next step of the Workshop idea.  RocketSat IV's mission was to provide undergraduate students an opportunity to get hands on experience working as a team and in doing so, take qualitative data of the flight environment. 

 

The RocketSat IV team was working with NOAA scientists with the goal of expanding the knowledge of the composition of the upper atmosphere by measuring the concentrations of carbon dioxide and methane above 30 km.  In order to do this, the team collected the atmosphere in a long section of tubing as the rocket fell back down to earth.  This method, called AirCore, was initially pioneered by NOAA using balloon flights.  A balloon flight is limited to an altitude of approximately 30 km (100,000 ft) and a sounding rocket more than doubles that altitude.  It was the first time an AirCore had ever been flown on a sounding rocket and had the potential to break an altitude record for highest collected continuous atmospheric sample.

The graph above was made following one of the balloon flights flown by NOAA.  The red circles indicate the CO2 relative to altitude and the black line shows the temperature profile of the atmosphere.

 

 

The AirCore will be collecting the atmosphere from apogee, 67 km, to just before parachute deployment, 6 km.  The data collected can then be compared to current theoretical and actual models of the CO2 and  methane in the upper atmosphere.  Both gasses are considered green house gasses and the AirCore project could potentially contribute towards research on global warming.

 

AirCore is the same idea as an artic ice core.  As the rocket falls, air is stacked into a long section of coiled tubing.  The AirCore relies on the pressure differential created by the increasing pressure through the atmosphere during descent to push air into the tubing.  It stays stacked in the relative order that it is collected in due to the rates of diffusion.  Diffusion over the small diameter of the tube happens quickly, however, over the entire length of tubing, diffusion is extremely slow.  It would take about 24 hours for the air molecules to diffuse about 3-4 meters and as time increases, the rate at which it diffuses becomes exponentially slower.

RocketSat IV expected to see the composition of carbon dioxide and methane decrease as altitude increased.  At sea level, carbon dioxide should be closer to 400 ppm, but it should drop off as altitude increases.  Methane should also show a decrease with altitude.  At higher altitudes, heavier gases are separated from lighter gases because there is no wind to the keep the molecules mixed. 

The bottom of the RocketSat IV payload.  In the center is the stack of CDH boards and around it is the smaller diameter tubing with the larger diameter tubing around the outside.  The drop down line that connects to the static port is also visible along with the solenoid.

The AirCore consists of two different coils of tubing for collection.  There are 200 ft of 1/8" tubing and 100 ft of 3/8" tubing.  The two coils are connected so that there are approximately 300 ft, total, of tubing that the atmosphere is collected and stored in.  Air first flows into the 3/8" tubing and then slowly moves into the 1/8" tubing.  The 1/8" tubing allows for a longer length of tubing to be inside the canister meaning a higher resolution sample is returned because it would take longer for the air to mix inside the small diameter and over such a long length.

The large diameter tubing is coiled around the inside edge of the canister while the small diameter tubing is more tightly coiled around a center stack of polycarbonate plates holding all of the electronics and other hardware.  The coils were secured with a Dacron string and separated by foam.  All of this fits inside the same canister the RockOn workshop used.  The end of the tubing was connected to a static port provided by Wallops, the launch provider. 

During the flight, pressure data, temperature data, and z-axis acceleration were being recorded.  There was a solenoid on the end of the tubing that would open at apogee and then close at approximately 6 km, based on pressure and timing. 

 

After the flight RocketSat IV found that the flash memory had become corrupted and the data returned was offset a considerable amount and data from more than half the flight was not recorded.  After analyzing the air in the coil, it appears that the solenoid did open and close, however, it did so based off of the timing fail safe which had it close much lower than initially wanted.  Also the data shows extremely high concentrations of both carbon dioxide (over 800 ppm) and methane (over 2 ppm) along with a high humidity inside the coil.  The air we were collecting should have been dry air and the carbon dioxide should have never been above 400 ppm while methane should have stayed just below 2 ppm and decreased in concentration from there.

 

The graph to the left is of the methane (blue) and the carbon dioxide (red) inside the coil of tubing vs. time through the analyzer.  The actual sample is between time 20 and time 65.  The steady values on either side of the coil are a known gas with consistent concentrations of the two key gasses. RocketSat IV was successfully launched and recovered with the other RockOn payloads.  Launch was June 27, 2008 from Wallops Island, VA on board an Improved Orion.