I was trying to have an idea about what kind of missions are on orbit cubesat performing and first I had a look into their orbital characteristics.
Importing tle files from Celestrak, provided by NORAD, I had access to orbital basic information in two lines elements format. I have converted this tle data into several orbital parameters. TLE Analyser is an open-source and freeware tool that can be used to extract different orbital parameter for each cubesat. Additionally can display satellites ground track and 3D visualisation embedding a google earth frame.
The data used in this analysis can be founded and the end of this post. As input TLE Analyser imported TLE from Celestrak downloaded at 20:30:00 1/1/2014 UTC . The propagation time is lower than 1 day meaning that estimation is quite accurate.
From these parameters the eccentricity indicates how the orbit of the cubesat is deviated of a perfect cycle. The POPACS (Polar Orbiting Passive Atmospheric Calibration Sphere) mission satellites have the maximum eccentricity with very similar values. POPACS 3 has an eccentricity of 0.079174. In the opposite side ORS OBJECT C with an 0.00044 of eccentricity represent the minimum in the list.
Statistical eccentricity data summary:
| Eccentricity | |
| Min | 0.0004435 |
| Max | 0.0791747 |
| Mean | 0.0098138 |
| Median | 0.0021277 |
| Standard Deviation | 0.0166244 |
Concerning the inclination of the orbit, ORS OBJECT C with 40.48 deg is mission with lower inclination whilst M_CUBED & EXP-1 PRIME with 101.71 deg is the maximal inclination.
Statistical inclination data summary:
| Inclination (deg) | |
| Min | 40.4879 |
| Max | 101.7176 |
| Mean | 78.09272 |
| Median | 97.77701 |
| Standard Deviation | 25.19258 |
Looking into the altitude characteristics we have 4 parameters to be analysed, maximal and minimum of altitude at apogee and at perigee. TECHEDSAT_3P has the minimum altitude at the apogee with 361.426 km and POPACS 2 has the maximum altitude at the apogee with 1466.3514 Km. This is the maximum altitude of a cubesat mission.
Statistical altitude at the apogee data summary:
| Altitude Apogee (km) | |
| Min | 361.426 |
| Max | 1466.3514 |
| Mean | 688.6249 |
| Median | 657.6180 |
| Standard Deviation | 193.1829 |
For the perigee we can find that CANX-1 with 813.042 km is the máximum altitude at the perigee of a cubesat. E_ST@R is with 280.3007 km at the perigee the cubesat with the lowest altitude.
Statistical altitude at the perigee data summary:
| Altitude Perigee (km) | |
| Min | 280.3007 |
| Max | 813.0423 |
| Mean | 549.7356 |
| Median | 563.7467 |
| Standard Deviation | 122.1465 |
Another important parameter is the period of the orbit in minutes. This is the time taken by the satellite to perform an orbit around the earth. TECHEDSAT_3P cubesat takes 91.54 min to complete an orbit. The satellite with a highest period is POPACS 2 with 103.02 minutes.
Statistical period data summary:
| Period (min) | |
| Min | 91.5443 |
| Max | 103.0204 |
| Mean | 97.0905 |
| Median | 97.0592 |
| Standard Deviation | 2.2806 |
It is expected that TECHEDSAT_3P with the minimum altitude at the apogee has the minimum period and POPACS 2 with the maximum altitude at apogee has maximum orbital period. This relationship is described in the equation
Orbital Period Equation
where,
Tk is the period,
a is the semi-major axis,
μ is the geocentric gravitational constant.
Data:
Cubesat Celestrak– Celestrak TLE file used as TLE Analyser input.
Raw Orbital Data Cubesat – Output raw data from TLE Analyser.
