What is CubeSat?

Images from brightsideofnews.com
and electronics-lab.com

California Polytechnic State University, San Luis Obispo, and Stanford University's Space Development Lab developed the CubeSat Program in 1999 to provide a cost-effective and reliable way to conduct satellite research. They accomplish this task by specifying the layout and design of a nano-satellite; the CubeSat Kit also includes access to required documents, licences, access to testing facilities, and means to transport and launch the satellite.

Due to this simple system, many educational institutions have proposed their own research projects within the CubeSat Program guidelines. In this sense, the CubeSat Projects act as means to collect meaningfull scientific data while creating notable educational opportunities. The program encourages student activity in the field of space science and continues to attract schools at both the undergraduate and high school levels. A history of past launches and descriptions of current programs can be found at the CubeSat Program's Home Page.

The CubeSat Satellite

A CubeSat satellite is a 10cm x 10cm x 10cm nano-satellite that weighs less than 1kg. These low-risk features make the CubeSat Program vital as a testing platform for new ideas. It can be configured with components to fit the differing CubeSat Program projects. By providing this standard skeleton, the program provides an opportunity to gather meaningful scientic data while engaging students in a valuable educational experience.

Images from amsat.org and cubesat.auc.dk

What is Cloud CubeSat?

Images from UMBC

Cloud CubeSat is the CubeSat Program under the University of Maryland-Baltimore County with the NASA Goddard Space Flight Center Climate and Radiation Branch. The overall mission of the project is to measure the vertical profile of clouds as an investigation of cloud microphysics and thermal properties. The current approach to measuring cloud composition is an inefficient, often inaccurate method. Researchers collect data by flying to various altitudes and accumulate the results into a general view of the vertical profiles. The greatest detriment to this approach is the large amount of time it takes to change altitude relative to the time in which cloud composition can change. This difference in time scales leads to inaccurate data and observations.

By using a low-orbiting satellite, researchers eliminate these detriments and obtain a reliable way of measuring cloud composition. The greatest benefits of using this approach is that the entire vertical profile of the cloud can be captures at once. This advantage allows researchers to view the change in cloud composition over time. Additionally, the profiles are caught at a constant angle, simplifying the calculations needed to measure the cloud composition as a function of altitude.

Finally, the advantagees of using a low-orbiting satellite are listed above. However, a typical CubeSat is too small to house all the components necessary in gathering the appropriate data. Consequently, the Cloud CubeSat makes use of three standard CubeSat satellites culminating in a 30cm x 10cm x 10cm pico- satellite.

Where We Come In

As the Cloud CubeSat satellite travels into the lower atmosphere, the SWIR detectors on the satellite reach temperatures up to 290K. At these high temperatures, freed electrons create electrical noise that interferes with the camera's image sensor. The success of the mission depends on delivering clear photographs of the vertical profiles, therefore, cooling the detectors is essential.

Thermoelectric coolers function to transfer heat from one side of the device to ther other and many devices exist that already optimize cooling time. The primary challenge we face, however, is the limited power supply of the Cloud CubeSat. The satellite's functionality is reduced to one device at any given time. As the thermoelectric cooler operates, other important functions such as the attitude control system --responsible for orienting the satellite--become disabled. By minimizing this time, we optimize the situation in which the satellite takes its pictures. Our challenge is therefore to develop an efficient controller system in terms of both time and long-term power dissipation.