Buccaneer CubeSat Mission
Buccaneer is a collaborative Australian project to jointly fly and operate two CubeSat missions developed by the DSTG (Defence Science and Technology Group) and UNSW (University of New South Wales) Canberra Space. It is highly significant in the context of Australian space activities as it will be the first, sovereignly developed defence-science CubeSat mission flown by Australia. 1)
The Buccaneer program consists of two missions with the key objectives; (1) calibration of the JORN (Jindalee Operational Radar Network) from space using an HF receiver payload, and (2) acquisition of high quality flight data for correlated Astrodynamics and SSA (Space Situational Awareness) experiments using the Buccaneer spacecraft in combination with ground sensor networks.
The primary objective of the overall two-flight program is to calibrate the radar signals from JORN from the vantage point of a spacecraft in LEO (Low Earth Orbit) where the radar waves are refracted by the ionosphere. 2) The radar transmits in the 3-45 MHz band from sites located in Australia (Figure 1) and is an operational defence facility.
The secondary objective of the program is to provide reliable experimental data to support astrodynamics and SSA research being carried out at UNSW Canberra. This objective will be achieved by measuring the light curves from ground based tracking telescopes in the FTN (Falcon Telescope Network) to develop and correlate models of the reflectivity of the spacecraft in the solar spectrum versus solar illumination angle, viewing aspect angle, spacecraft attitude and atmospheric conditions.
Figure 1: View of the JORN antenna array (image credit: DSTG)
The first mission in the program is the BRMM (Buccaneer Risk Mitigation Mission); currently manifested for launch into a sun synchronous orbit on the ELaNa-XIV launch in November 2017 with the nominal orbital parameters listed in Table 1.
Table 1: BRMM nominal orbital parameters
Buccaneer Risk Mitigation Mission: The BRMM spacecraft bus is a customized Pumpkin MISC3 which complies with the 3U+ CubeSat specification. Table 2 lists the major payload and platform elements and suppliers. The flight model spacecraft has completed its flight qualification and acceptance testing and has been integrated into its CubeSat dispenser. The image of Figure 2 shows the spacecraft immediately prior to integration into the dispenser with all of the deployables stowed in the launch configuration. The 3U CubeSat has a mass of 4 kg.
Table 2: Major subsystems of the BRMM spacecraft
Figure 2: BRMM flight model 3U CubeSat (image credit: Buccaneer collaboration)
BRMM - Technology pathfinder:
One of the critical and enabling technologies for the overall Buccaneer program is the HF receiver antenna on the spacecraft. Given the low TRL (Technology Readiness Level) of the antenna design, the practical obstacles to conducting flight representative tests of the antenna deployment in a terrestrial 1-g environment, and the intractability of developing reliable mathematical models of the antenna dynamics, it was agreed to implement a dedicated technology pathfinder mission; the BRMM (Buccaneer Risk Mitigation Mission) in order to gain flight heritage on this technology ahead of the Buccaneer Main Mission. 3) 4) 5)
There are two obvious challenging aspects to the design of the antenna; firstly, it has a very large operating RF bandwidth of nearly four octaves (3-45 MHz) and secondly, the physical size of the antenna needs to be large to match the wavelength of the signals. The antenna configuration which best suited the Buccaneer requirements is an open bow-tie antenna (Figure 3) with four elements approximately 1.7 m long.
Figure 3: BRMM spacecraft showing the deployed HF antenna in green (image credit: Buccaneer collaboration)
Since the physical size of the antenna is much larger than the dimensions of the 3U+ BRMM spacecraft, the antenna has to be stowed prior to launch and then reliably deployed once the spacecraft is on orbit. The physical volume available to the antenna in the stowed configuration is the "Tuna can"; a ø 64 mm x 36 mm cylindrical envelope defined in the CubeSat Specification. This stay-in envelope places stringent design constraints on the antenna deployment mechanism and on the amount of material that can be used to stiffen the antenna in the deployed state. The selected antenna design consists of four elements of carpenter's tape wrapped on a spool and held down in the launch configuration with staged burn wires. The flight model design of the HF antenna in the stowed configuration and the RF payload elements are illustrated in Figure 4.
The RF payload on BRMM does not contain all of the requisite elements to perform the calibration of the JORN signals, but does include some technically challenging, low TRL electronic circuits which will gain flight heritage and qualification as part of the mission. The BRMM antenna, RF payload and integrated spacecraft have been qualified for flight by passing all their functional, performance and environmental tests.
Figure 4: BRMM payload showing the stowed HF antenna (image credit: Buccaneer collaboration)
Figure 5: BRMM flight model spacecraft during preparation for thermal vacuum testing (image credit: Buccaneer collaboration)
BRMM SSA (Space Situational Awareness) experiments:
The science of astrodynamics applied to understanding the natural perturbations of objects in LEO (Low Earth Orbit) is poorly understood. The interaction of orbiting objects with the space environment can result in apparently chaotic orbital perturbations and give rise to difficulties in tracking, updating ephemeris and predicting conjunction probabilities.
The BRMM spacecraft will be used to conduct experiments to grow the understanding of how spacecraft interact with their environment and the governing physics of the perturbations. Primarily, this will be done by observing the spacecraft with elements of the FTN (Falcon Telescope Network) during passes when the spacecraft is under solar illumination. The telescope will track the spacecraft in its field of view and gather temporally resolved, photometric light curves of the reflected solar light as it passes within the field of regard of the telescope. This light curve data will be correlated with models of the geometric/optical properties of the spacecraft, the solar illumination vector, the spacecraft attitude, the observation vector and the atmospheric conditions. After these models have been validated with the BRMM data, they can then be used to gain an understanding of the physical parameters of unresolved objects with light curve data and improve estimates of their orbit propagation.
BMM (Buccaneer Main Mission):
After the successful launch, commissioning and HF antenna deployment, the BRMM spacecraft will conduct attitude maneuvers to establish the stability margins of the HF antenna. This information will enable BMM to kick off the flight program. The payload on BMM will contain all of the antenna, RF front end and digital back end elements to calibrate the JORN signals.
The Concept of Operations for the BMM is shown in Figure 6. The procedure is initiated (i) during contact with the ground station and the uploading of a set of telecommands to configure the spacecraft and payload. In general, (ii) the payload will be put into a low power mode to conserve electrical power on the platform. As the spacecraft approaches the location for the collection of the RF signals, the payload is switched on (iii), allowed to stabilize and the RF signal collected. Once again, the payload would be put into a low power mode (iv) until the OBC sends a command to the payload (v) to process the acquired RF signal data (vi). Once the data has been processed, it would be put into a low power mode (vii) until the spacecraft makes contact with the ground station and is able to download the payload data (iix) via the S-band link and then put into low-power sleep mode again.
Figure 6: BMM RF payload concept of operations (image credit: Buccaneer collaboration)
The baseline configuration of the BMM spacecraft is to rely on the heritage obtained from the BRMM mission, but other options are to be investigated to assess the benefits of incorporating technologies developed within the wider UNSW Canberra and DST space mission programs and factor in the lessons learned from the BRMM program.
In summary, the DSTG/UNSW Canberra Buccaneer partnership has successfully developed the BRMM spacecraft (Figure 7) and will be the first Australian, defence-science CubeSat mission. The BMM is planned to follow the launch in approximately 18 months afterwards.
Figure 7: Artists impression of the BRMM spacecraft (image credit: Buccaneer collaboration)
Launch: The Buccaneer 3U CubeSat was launched as a secondary payload on Nov. 18, 2017 on a Delta-2-7920 vehicle of ULA (United Launch Alliance) from VAFB, CA, USA. The primary mission was the JPSS-1 spacecraft of NOAA, developed at NASA. 6) 7)
Orbit: The design orbit for the Buccaneer mission is an elliptical sun-synchronous orbit with a perigee of 440 km and an apogee at 810 km, inclination = 97.7º, LTAN (Local Time of Ascending Node) = 13:35 hours.
Orbit of JPSS-1: Sun-synchronous orbit, altitude of 824 km, inclination = 98.7º, period = 101 minutes.
Secondary payloads (ELaNa-14):
• RadFxSat (Radiation Effects Satellite, Fox-1B), a 1U CubeSat of AMSAT and Vanderbilt University, Nashville, TN, USA.
• EagleSat, a 1U CubeSat of ERAU (Embry-Riddle Aeronautical University), Prescott, AZ, USA.
• MakerSat-0, a 1U CubeSat of NNU (Northwest Nazarene University) of Nampa, Idaho, USA.
• MiRaTA (Microwave Radiometer Technology Acceleration), a 3U CubeSat of MIT (Massachusetts Institute of Technology), Cambridge, MA, USA.
• BRMM (Buccaneer Risk Mitigation Mission), a 3U CubeSat technology mission of UNSW (University of New South Wales), Canberra, Australia and DST (Defence Science and Technology) group. The goal is to calibrate JORN (Jindalee Over-the-Horizon Radar Network).
- Buccaneer will help calibrate Australia's groundbreaking Jindalee over the horizon radar as well as provide crucial data on predicting orbits of space objects including space "junk".
- Over the next few weeks and months the spacecraft will undergo operations to check and commission its systems before undertaking its risk mitigation activities and experiments in early 2018.
• All CubeSats have been deployed! P-POD 1 released EagleSat-1, RadFXSat and MakerSat-0; Buccaneer deployed from P-POD 2; and MiRaTA deployed from P-POD 3. The CubeSats all are flying solo to begin their missions. 10)
- Orbit: All CubeSats were deployed into an elliptical sun-synchronous orbit with a perigee of 440 km and an apogee at 810 km, inclination = 97.7º.
• Approximately 63 minutes after launch the solar arrays on JPSS-1 deployed and the spacecraft was operating on its own power. JPSS-1 will be renamed NOAA-20 when it reaches its final orbit. Following a three-month checkout and validation of its five advanced instruments, the satellite will become operational. 11)
1) Douglas Griffina, David Lingard, Matthew Young, Melrose Brown, A. Andrew Lambert, Russell Boyce, "DST Group and USNW Canberra Buccaneer Program," Proceedings of the 68th IAC (International Astronautical Congress), Adelaide, Australia, 25-29 Sept. 2017, paper: IAC-17-B4.2.6
2) "Defence starts research into miniature satellites," URL: https://www.engineersaustralia.org.au/News
3) Russell Boyce, "UNSW Canberra Space CubeSat missions – why, how and what," URL: http://www.acser.unsw.edu.au/sites/acser/files
5) "Small satellite missions," Australian Government, Department of Defence, Science and Technology, " URL: https://www.dst.defence.gov.au/sites/default
6) Steve Cole, John Leslie, "NASA Launches NOAA Weather Satellite Aboard United Launch Alliance Rocket to Improve Forecasts," NASA, 18 Nov. 2017, Release 17-086, URL: https://www.nasa.gov/press-release/nasa-launches-noaa-weather-satellite-aboard-united-launch-alliance-rocket-to-improve
7) "ELaNa XIV CubeSats Launch on JPSS-1 Mission," NASA, 18 Nov. 2017, URL: https://www.nasa.gov/feature/elana-xiv-cubesat-launch-on-jpss-1-mission
8) "UNSW Canberra launches first satellite into space," Space Daily, 28 Nov. 2017, URL: http://www.spacedaily.com/reports/UNSW_Canberra
9) Jamie Seidel, "Cubesat Buccaneer: Australia takes its first steps towards rejoining the space race,"News Corp Australia Network, 26 Nov. 2017, URL: http://www.news.com.au/technology/science
10) "All CubeSats Successfully Deployed," NASA, 18 Nov. 2017, URL: https://blogs.nasa.gov/jpss/2017/11/18/all-cubesats-successfully-deployed/
The information compiled and edited in this article was provided by Herbert J. Kramer from his documentation of: "Observation of the Earth and Its Environment: Survey of Missions and Sensors" (Springer Verlag) as well as many other sources after the publication of the 4th edition in 2002. - Comments and corrections to this article are always welcome for further updates (firstname.lastname@example.org).