FIREBIRD (Focused Investigations of Relativistic Electron Burst Intensity, Range, and Dynamics)

FIREBIRD is a collaborative CubeSat space weather mission of two 1.5U CubeSats, designed and developed by Montana State University (MSU, Bozeman, MT), University of New Hampshire (UNH, Durham, NH), The Aerospace Corporation (El Segundo, CA), and LANL (Los Alamos National Laboratories, Los Alamos, NM). The collaboration is referred to as the FIREBIRD consortium. The mission objective is to assess the spatial scale and spatial temporal ambiguity of magnetospheric microbursts in the Van Allen radiation belts. The FIREBIRD mission is funded by NSF (National Science Foundation).

Background: Relativistic electron microbursts appear as short durations of intense electron precipitation measured by particle detectors on low altitude spacecraft, seen when their orbits cross magnetic field lines which thread the outer radiation belt. Previous spacecraft missions (e.g., SAMPEX) have quantified important aspects of microburst properties (e.g., occurrence probabilities), however, some crucial properties (i.e., spatial scale) remain elusive owing to the space-time ambiguity inherent to single spacecraft missions. While microbursts are thought to be a significant loss mechanism for relativistic electrons, they remain poorly understood, thus rendering space weather models of Earth’s radiation belts incomplete. FIREBIRD’s unique two-point, focused observations at low altitudes are expected to answer three fundamental scientific questions with space weather implications: 1) 2) 3) 4) 5) 6)

1) What is the spatial scale size of an individual burst? The study should gain a better insight into the causes as well as a better insight into total radiation belt losses due to microbursts. Generally, microbursts occur in discrete “packets”. FIREBIRD will help resolve the spatio/temporal ambiguity and determine the size of the microburst region as the spacecraft drift apart.

2) What is the energy dependence of an individual burst? The study should provide a better insight into the causes and a better insight into total radiation belt loss due to microbursts. What resonance conditions are occurring?

3) How much total electron loss do bursts produce globally? The study should provide an estimate of how important microbursts are in the system as a whole and give a better insight into total radiation belt loss due to microbursts.

Current and planned measurements alone cannot answer these questions, it takes low-altitude multi- point measurements. Microbursts are short (~100 ms) bursts of precipitation. Initial work in this field started in the 1960s from balloon measurements and has been studied sporadically since then.

In addition to addressing fundamental space physics research and space weather applications, the FIREBIRD investigation also contributes to the training and educations of a diverse population of university students in all phases of the project. Students will have major responsibility for the design and implementation of the instruments and the spacecraft while at the same time being mentored by professionals in each expert area.

To achieve the spatial and temporal requirements of the mission, a GPS (Global Positioning System) receiver, for the purpose of navigation position and timing, is to be implemented on both satellites within the constellation. The integration and testing of this subsystem is integral to the mission’s success. The GPS hardware must be capable of fulfilling the requirements of the mission in order for the science data to be interpreted reliably.

The operational mission has a timeline of ~ 3 years. In 2009, the FIREBIRD project was awarded a funding contribution by NSF (National Science Foundation).


Figure 1: Photo of the two FIREBIRD nanosatellites (image credit: MSU/SSEL) 7)


The mission uses two identical CubeSats (1.5U form factor) each with a size of 10 cm x 10 cm x 15 cm and a mass of ~2 kg. The CubeSats features passive magnetic attitude control. In addition, use of a single frequency GPS receiver (NovAtel OEMV-1), a 16-channel device in a 46 mm x 71 mm form-factor with low power consumption.

The two nanosatellites were developed by SSEL (Space Science and Engineering Laboratory) at MSU (Montana State University), Bozeman, MT, USA.


Figure 2: View of the spacecraft layout (image credit: FIREBIRD consortium)

CDHS (Command and Data Handling Subsystem): The CDH board was purchased from Pumpkin Inc. Containing a PIC24 microcontroller, a FLASH RAM chip, and an SD card reader. This allows the software to process and store data in multiple formats all on one board. The PIC24 microcontroller is the brain of the FIREBIRD system. It is a 16 bit, modified Harvard architecture that can reach 16 MIPS when run at 32 MHz. The 32 MHz clock is accomplished by using a PLL (Phase Lock Loop) on the internal 8 MHz oscillator. FIREBIRD uses this PLL to reach these higher speeds and to allow for faster inter-hardware communication.

EPS (Electrical Power Subsystem) of Tiger Innovations:

- SA inputs: 4 independent PPTs (Peak Power Trackers) with 2.5 A max per channel

- Battery: Li-ion1.8 Ah 4.2 V cells (x 2)

- Shunt: Dissipates excess array power

- Power: < 50 mW quiescent draw

- Size: 96 x 90 x 20 mm (w/battery)

- Mass: 167 g (w/battery)

- Output voltages: 8.4 V (2 switchable channels) (unregulated bus voltage). 5 V @ 2 A, 3.3 V @ 2 A.


Figure 3: Photo of the EPS (image credit: FIREBIRD consortium)

RF communications: Data transmission is provided in UHF (437.405 MHz and 437.230 MHz) at a data rate of 9.6 kbit/s. Use of GMSK (Gaussian Minimum Shift Keying) modulation and Ax.25 protocol.


Figure 4: Engineering model of a single FIREBIRD satellite (image credit: FIREBIRD consortium)


Launch: The two FIREBIRD CubeSats were launched as secondary payloads on Dec. 6, 2013 (07:14:30 UTC) on an Atlas-5-501 vehicle from VAFB, CA. The primary payload on this flight was the classified NROL-39 reconnaissance mission of NRO (National Reconnaissance Office). The launch provider was ULA (United Launch Alliance). 8) 9) 10) 11) 12)

Note: The NROL-39 is reported to be a Topaz radar-imaging reconnaissance satellite with the FIA Radar-3 payload of the cancelled FIA (Future Imaging Architecture) program. FIA was a program to design a new generation of optical and radar imaging US reconnaissance satellites for NRO. Despite the optical component's cancellation in 2005, the radar component, with a code name of Topaz,has continued, with two satellites in orbit as of November 2013; these are: NROL-41, launched on Sept. 21, 2010, and NROL-25, with a launch on April 03, 2012. A total of 5 radar satellites are in the Topaz program (Ref. 9). 13)

Secondary payloads: Next to the NROL-39 primary payload, the Atlas-5 hosts the GEMSat/ELaNa-2 mission for the NRO and the NASA/LSP ( Launch Services Program), lifting 12 CubeSats/nanosatellites to orbit as secondary payloads. All 12 CubeSats/nanosatellites are considered to be technology missions. 14) 15)

• AeroCube-5a and -5b, two 1.5U CubeSats of The Aerospace Corporation.

• ALICE (AFIT LEO iMESA CNT Experiment), a 3U CubeSat of AFIT (Air Force Institute of Technology)

• CUNYSAT-1 (City University of New York-1), a 1U CubeSat of Medgar Evers College, Brooklyn, N.Y. of the City University of New York.

• FIREBIRD-A and -B, two 1.5U CubeSats of Montana State University, University of New Hampshire, Los Alamos National Laboratory, and The Aerospace Corporation.

• IPEX, a 1U CubeSat of Cal Poly (California Polytechnic State University) and NASA

• MCubed/COVE-2, a 1U CubeSat of the University of Michigan, Ann Arbor, MI and NASA/JPL

• SMDC-ONE-2.3 (Charlie) and SMDC-ONE-2.4 (David), two 3U CubeSats of the U.S. Army SMDC/ARSTRAT (Space & Missile Defense Command/Army Forces Strategic Command) of Huntsville, AL (Redstone Arsenal)

• SNaP (SMDC NAnosatellite Program), a 3U CubeSat of the U.S. Army SMDC/ARSTRAT

• TacSat-6, a 3U CubeSat of the U.S. Army SMDC/ARSTRAT.

The CubeSats are integrated into 8 P-PODs (Poly-Pico Orbital Deployers ), which are contained in the NPSCuL (Naval Postgraduate School CubeSat Launcher), built by NPS students. The NPSCuL, together with the 8 P-PODs and 12 CubeSats, is referred to as GEMSat (Government Experimental Multi-Satellite), and is attached to the Centaur upper stage's ABC (Aft Bulkhead Carrier). The assembled GEMSat is shown in Figure 5 ready for mate to the launch vehicle along with the members of the various institutions from NPS, OSL (Office of Space Launch), ULA (United Launch Alliance) and Cal Poly. 16)


Figure 5: Photo of the GEMSat/ELaNa-2 secondary payload along with all team members (image credit: GEMSat Team)

Orbit: The primary payload was launched into a Sun-synchronous near-circular orbit, altitude of ~1075 km x 1089 km, inclination of 123º (deployment ~07:32 UTC).

• The Centaur AV-042 upper stage then made two orbit lowering burns to a SSO of 467 km x 883 km at an inclination of ~120.5º. Attached to the AV-042 was GEMSAT, the second NPSCuL CubeSat launcher, which ejected 12 CubeSats between around 10:22 and 10:38 UTC. 17)

The two FIREBIRD satellites will remain within ~400 km of one another for up to four months, allowing characterization over the spatial scale regime from 10-300 km.


Figure 6: Atlas-V 501 launch vehicle with the ABC for the CubeSat accommodations (image credit: ULA, Ref. 14)


Mission status:

• Dec. 09, 2013: The orbiting FIREBIRD nanosatellites have begun probing a mysterious physical process within our planet's dangerous radiation belts. That process, known as microbursts, involves electrons moving at nearly the speed of light during short-duration (< 100 ms) events. Microbursts are thought to be one of the primary mechanisms by which the outer radiation belt loses energetic particles to Earth's atmosphere after the occurrence of powerful solar storms. Such storms can dramatically change the intensity of the radiation belts. 18)



Sensor complement: (FIRE)

FIRE (Focused Investigations of Relativistic Electrons)

UNH developed the FIRE assembly. FIRE employs a heritage sensor design based on a single large-geometry-factor, solid-state detector set on each of the two spacecraft, sensitive to electrons precipitating from the radiation belts.

Each satellite carries two solid-state detector charged particle sensors with different geometric factors optimized to cover electron measurements over the energy range from 0.25 to ~1 MeV in six differential energy channels. 19)


Figure 7: Photo of a single engineering unit sensor assembly (image credit: UNH)

Legend to Figure 7: The sensor assembly houses two solid-state detectors, one (bottom right corner) collimated and the other (top left corner) uncollimated.

The detectors are read out by a customized ASIC (Application-Specific Integrated Circuit), designed by The Aerospace Corporation, called the Dual Amplifier Pulse Peak Energy Rundown ASIC. Onboard memory stores fast sample observations needed to resolve the spatial structure; survey observations identify times of interest to download the highest temporal resolution data within the limited telemetry stream. While all data from the instruments are saved on board for ~4 weeks, FIREBIRD telemeters a reduced event identification data product to the ground each day in order to select particular intervals with microbursts to download for scientific analysis. 20) 21)


1) Brian Larsen, Harlan Spencer, David Klumpar, Larry Springer, J. Bernard Blake,“Focused Investigations of Relativistic Electron Burst Intensity, Range, and Dynamics (FIREBIRD),” CubeSat Developers' Workshop, CalPoly, April 22-25, 2009, URL:

2) David. M. Klumpar, Harlan E. Spence, Bernie Blake, “Overview: The Dual-CubeSat FIREBIRD Mission (Focused Investigations of Relativistic Electron Burst Intensity, Range, and Dynamics),” Nov. 30, 2009, URL:

3) Mackenzie Charles Wilz, “Focused Investigations of Relativistic Electron Burst Intensity, Range and Dynamics Space Weather Mission Global Positioning System,” Thesis for Master of Science in Electrical Engineering, Montana State University, Bozeman, MT, January 2011, URL:

4) Ian Lyon, “The Separation of a Two-Nanosatellite System via Differential Drag,” Thesis at MSU, April 2011, URL:

5) Ehson Mosleh, “FIREBIRD and SSEL Space Weather Missions,” CubeSat Developers Workshop, San Luis Obispo, CA, April 20, 2011, URL:

6) Marcello Ruffolo, Nathan Hyatt, Jordan Maxwell, “FIREBIRD Science Overview,” Aug. 2, 2013, URL:



9) William Graham, “Atlas V launches NROL-39 from Vandenberg,” NASA, Dec. 5, 2013, URL:

10) Stephen Clark, “Government spy satellite rockets into space on Atlas 5,” Spaceflight Now, Dec. 6, 2013, URL:

11) NROL-39, United Launch Alliance Atlas V Rocket Successfully Launches Payload for the National Reconnaissance Office,” ULA, Dec. 6, 2013, URL:

12) “UNH Scientists Launch “CubeSats” into Radiation Belts,” UNH, Dec. 9, 2013, URL

13) “Future Imagery Architecture,” Wikipedia, URL:

14) Patrick Blau, Atlas V to launch with classified NROL-39 & 12 CubeSats in December, Nov. 15, 2013, URL:

15) Bryan Klofas, “Upcoming CubeSat Launches: The Flood Has Arrived,” AMSAT-NA Symposium Houston, TX, USA, 1 November 2013, URL:

16) “Atlas V GEMSat Launch 2013,” URL:

17) Jonathan's Space Report No. 690, Dec 6, 2013, URL:

18) David Sims, UNH, Dec. 09, 2013, URL:

19) H. E. Spence, J. B. Blake, A. B. Crew, S. Driscoll, D. M. Klumpar, B. A. Larsen, J. Legere, S. Longworth, E. Mosleh, T. P. O’Brien, S. Smith, L. Springer, M. Widholm, “Focusing on Size and Energy Dependence of Electron Microbursts From the Van Allen Radiation Belts,” Space Weather, Vol. 10, S11004, 2012, doi.10.1029/2012SW000869, URL:


21) “Big Science in a Pintsize Package,” UNH EOS Spheres Newsletter, Summer 2012, URL:

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.