NEE-01 Pegasus (Ecuadorian Space Ship-01, a CubeSat Mission)
Pegasus is a 1U CubeSat project of EXA (Ecuadorian Civilian Space Agency) which started in 2010. The overall objective of the project is to serve as technology and capability demonstrator - the goal is to serve the elementary schools of Ecuador with a spaceborne learning tool platform which will inspire the next generation of domestic engineers. 1) 2) 3)
The EXA ground rule for funding is the development of an indigenous low-cost satellite mission — with the consequence that all design/development and manufacturing steps have to be done within the country, requiring a pioneering effort by all Ecuadorians involved.
The project is striving to achieve the following technology demonstration goals:
• To survive the space environment and transmit telemetry for at least a year
• Transmit real time, live video from orbit and OSD telemetry
• To test the space environment attenuation capabilities of the SEAM/NEMEA shield
• To test the passive release/deploy nano-morphodynamics technology of the multipanel ultrathin solar arrays
• To test the high energy generation/storage matrix technology
• To test the hyper amplification matrix ARGOS-MINOTAUR
The educational goals of the mission are:
• To serve as an elementary education spaceborne platform
• To serve as an undergraduate education spaceborne platform
• To demonstrate the benefits of an educational satellite.
The spacecraft was designed with a 1U CubeSat form factor having dimensions of 10 cm x 10 cm x 10 cm (in launch configuration) and a mass of ~1.26 kg. The satellite features two solar panel wings with 3 panels on each side for a total of 6 panels per wing, its deployed dimensions are 10 cm x 10 cm x 75 cm.
EPS (Electrical Power Subsystem): The EPS, devloped at EXA, is capable of operation without batteries on solar power only, it is MCU-driven EPS with 8 input power channels each capable of supporting 6 V@2 A and 25 ms switching capability, each input channel corresponds to a solar panel, 4 of them in the +X, -X, +Y, -Y and 4 in the +Za (dorsal side), +Zb(ventral side), -Za(dorsal side) and –Zb(ventral side) for the DSA solar wings.
The EPS included 32 SSR chips giving the module the capability of managing each one of the 32 battery cells in the 2 battery banks, each one with 16 cells being connected in parallel for an output of 3.7 V@28.8 A. This output in turn was distributed to 4 power channels of 16 V, 12 V, 5 V and 3.7 V to power the main payload and the command reception systems, as well as the PERSEUS device and active DSA release in the specific case of the NEE-02.
Figure 1: The EPS flight model during assembly and near completion (image credit: EXA)
PMSS: This is the spacecraft navigation system, which uses the EMF (Earth's Magnetic Field) to stabilize its position in 1 axis, using 4 linear arrays of magnets and 2 sets of HyMu-80 inertial-magnetic dampers.
SEAM/NEMEA: Its purpose is to moderate the spacecraft temperature, to block the Alpha, Beta, X, Gamma and GCR (Galactic Cosmic Rays) within the limits of the possible, without producing Bremsstrahlung radiation.
DSA: It handles the unfolding and release of the multipanel solar arrays, is made of 99.98% pure Titanium and 1.5mm thickness, and reaches 27 cm once fully deployed, it is activated by the heat of the sun, using nanomorphodynamic techniques and memory metals.
ADS (Antenna Deployment System): The ADS is based on memory metals; it is deployed using the solar radiation (heat).
NTDS: The thermal distribution system uses internal heat to equalize the temperature inside the S/C, and is made of a thin layer of multiwall carbon nanotubes over a heat-reflecting shield to route the heat properly and use it during the eclipse phase of the orbit.
RF communications: Center frequency at 910 MHz, bandwidth = 25 MHz, EIRP=34.1 dBm, carrier = FM, modulation audio: AMTW.
Figure 2: Illustration of the Pegasus CubeSat with the deployed solar wings (image credit: EXA)
The satellite was completely designed and built in Ecuador, without any foreign assistance, by an EXA engineering team led by Ronnie Nader.
Launch: The NEE-01 Pegasus (aka NEE-01 Pegaso) CubeSat was launched as a secondary payload on April 26, 2013 on a Long March 2D vehicle of China. The launch site was the Jiuquan Satellite Launch Center, China. The primary payload on the flight was GF-1 (Gaofen-1), an Earth observation mission of CNSA, China. 4) 5)
Orbit: Sun-synchronous orbit, altitude of 630 x 657 km, inclination =98.04o, period = 97.45 minutes, LTAN (Local Time on Ascending Node) = 22:30 hours.
The secondary payloads were:
• TurkSat, a nanosatellite (3U CubeSat, ~ 4 kg) of ITU (Istanbul Technical University), Istanbul, Turkey.
• NEE-01 Pegasus, a 1U CubeSat of EXA, Ecuador.
• CubeBug-1 of INVAP, a 2U CubeSat of Argentina, sponsored by the Argentinian Ministry of Science, Technology and Productive Innovation, INVAP S.E., Satellogic SA, and Radio Club Bariloche.
The secondary payloads of the flight are coordinated by ISIS (Innovative Solutions In Space, BV) of Delft, The Netherlands.
The project invited the Ecuadorian Air Force (FAE) to participate in the launch phase and operations of the CubeSat mission. The FAE and the EXA will operate the satellite jointly, sharing the technological and scientific benefits of the mission as a first step towards establishing a national satellite program.
• The NEE-02 CubeSat of EXA was launched as a secondary payload on Nov. 21, 2013. It was part of the Dnepr Cluster mission from Yasny Cosmodrome, Russia with the primary payloads DubaiSat-2 of EIAST and STSat-3 of KARI, Korea (Ref. 9).
- The NEE-02 carried a novel device called "PERSEUS" which allowed the Ecuadorian Civilian Space Agency (EXA) to recover the signal of the NEE-01 PEGASUS via intersatellite communication. - Prior to launch, the EXA project NEE-02 installed a simple repeater inside the NEE-02 as a secondary payload, a small reception device tuned in the same frequency of the transmission frequency of the NEE-01 and directly connected to the input of the main transmitter of the NEE-02.
- By mid-December 2013, the EXA team was able to make the first successful in-orbit tests of the PERSEUS device at a maximum range of 2000 km of separation between the spacecrafts and minimum range of 800 km of separation, the team could hear the audio portion of the whole signal coming from NEE-01.
- Although the repeater was designed to re-transmit the full video and audio signal, we were only able to receive the audio portion of the signal; however, this was enough for the team at that time to know that many of the assumptions were correct regarding the functionally of both the PERSEUS device and the NEE-01.
• By the end of August 2013, this signal channel was stable; however, being the most powerful in the whole signal, it would not raise over -83 dBm and the whole signal would not raise over -85 dBm in the best case.
- Reaching the end of August also meant that we were near the deadline of the insurance policy coverage. Not being able to regain the signal of the NEE-01, the project notified the proper authorities which in turn notified the insurance company. The insurance company awarded the policy in due time. And the project had to declare the NEE-01 mission as lost - a rather sad experience for all involved (Ref. 9).
• July 2013: The NEE-01 survived the crash and remains in orbit; however it has entered uncontrolled rotation due to the collision event. Due to this rotation, the satellite cannot point its antenna correctly and stably to the Earth station and although still transmitting and running, the signal cannot be decoded. EXA (Ecuadorian Civilian Space Agency) is working tirelessly to stabilize the NEE-01 and recover the use of their signal. 6)
• On June 13, 2013, the team was able to gain command of the activation and deactivation during the night passes, There were some few options at hand to do every time we had a high pass to make NEE-01 stop rotating until the PMSS navigation system could take over. If the team would be able to achieve that threshold, it was only a matter of days that the spacecraft should stabilize and we could broadcast again (Ref. 9).
- From this point forward, the team attempted to receive the signal from NEE-01 almost every day; but it soon dawned on us that in this conditions it would be futile to attempt contact in days where the passes where not over 30o. In the best days, the team could detect a faint EM signature, for us this meant that we could see a very small ‘walking' carrier signal just over the -89 dBm threshold traveling from +910.xxx to -909.xxx with a 20 to 25 MHz bandwidth which was coincident with the orbit of NEE-01's Doppler change expected and with the time and day of the pass, the team made many tests to rule out background noise (Ref. 9).
- The team nicknamed this faint EM signature as TGP (The Ghost of PEGASUS).
• May 23, 2013: Ecuador's first satellite, launched last month, has collided with debris from an old Russian rocket but it is unclear if it has been damaged, officials say. 7)
- Also on May 23, the project received a CAN update indicating that a full collision had not happened. At 10:42 local time during the very first pass after the conjunction,the team was not able to detect any meaningful signal from NEE-01, nor in subsequent passes up until a week later when the project was able to detect the vertical sync TV signal appearing and disappearing at a high pass in the sky, not enough to form an image, but enough to be sure that the satellite was rotating. NEE-01 carries 2 Tx antennas and 4 Rx antennas (Ref. 9).
• On May 22, 2013, the project received an update of the CAN indicating that the radial miss had reduced even further and was 58 m then (Ref. 9).
• The last meaningful transmission of NEE-01 was on May 21 2013 starting at 23:12. On May 22 2013, there were no scheduled transmissions as the passes were too low, however after a long analysis EXA decided to put the satellite in survival (safe) mode, which meant that it would broadcast continuously along its orbit with nominal power, as opposed to operating in the Overlord mode in which it transmits only when activated by HERMES-A ground station and with high power. This command was sent to the satellite during low passes on May 22 at 21:00 and at 23:00 local time (Ref. 9).
• On May 21, 2013, the project received a CAN (Close Approach Notification) from JSpOC/NORAD informing EXA as the satellite operator, that a probable conjunction would occur between NEE-01 and NORAD Catalog Number 15890 on May 23 at 05:38 UTC. After analyzing the data, EXA came to the conclusion that the conjunction was risky as the Radial Miss Distance was only 62 m (Ref. 9).
• On May 16, 2013, NEE-01 Pegaso transmitted its first live video with audio. 8)
Figure 3: A snapshot of the first public video transmitted by the NEE-01 on May 16 2013 in a pass over South America (image credit: EXA) 9)
• Since May 8, 2013 NEE-01 Pegaso is only active in the presence of the coded signal sent by the HERMES-A ground station, it is currently operating in high power mode, that means that it remains off until activated by the ground station to conserve power. 10)
The spacecraft's instruments include a dual visible and infrared camera which allows the spacecraft to take pictures and transmit live video from space. The video camera is a 720p HD camera to send live video from space using a 3 W TV transmitter in the 915 MHz (33cm) band along with a beacon that provides a Morse code ID, a SSTV (Slow Scan Television) image and Ecuador's national anthem. 11)
The NEE-01 Pegasus CubeSat uses the existing HERMES-A ground station, located in Guayaquil, Ecuador. However, the reception sensitivity of the station had to be dramatically enhanced to receive and decode a real time video transmission from orbit arriving to the antenna with signal levels as low as -160 dbm. The solution was the ARGOS (Advanced Radio signal Gathering from Orbiting Spacecraft) manifold which resembles more a radio telescope than a normal ground station. 12)
The HERMES station project was started in 2009; it rendered a ground station not only able to efficiently operate satellites in the HF to K-bands, but it also became the first Internet to orbit gateway, enabling the nation to acquire many capabilities such as space traffic monitoring and even the capability to relay live scientific satellite signals to any point in the world.
So far, the HERMES-A ground station has rendered excellent results. It is also used as a laboratory permitting the project team to experiment and to learn for ourselves about satellite technology from firsthand experience. — In addition, the HERMES-A ground station is providing its tracking services to other space missions of the international community, such as those of JAXA (Japan Aerospace Exploration Agency), Michigan State University, Graz Technical University (TUGSat-1), and the Swiss EPFL (Federal Institute of Technology Lausanne).
Occasionally, the HERMES-A station is being used in support of national security events, when monitoring possible spacecraft collisions (range of 6000 km), like the event of February 5, 2010 between a Iridium 33 debris and the EPFL SwissCube.
When the HERMES-A/Minotaur G/S gateway was complete in April 2010, the EXA Directorate approved a project proposed by Cmdr. Ronnie Nader, the development of the first
1) Ronnie Nader, Hector Carrion, Sidney Drouet, Manuel Uriguen, Ricardo Allu, Gonzalo Naranjo, "NEE-01 PEGASUS: The first Ecuadorian Satellite," Proceedings of IAC 2011 (62nd International Astronautical Congress), Cape Town, South Africa, Oct. 3-7, 2011, paper: IAC-11.B4.1.6, URL: http://www.academia.edu/772243/NEE-01_PEGASUS_The_first_Ecuadorian_Satellite
4) "China launches Gaofen-1 satellite," Xinhua, April 26, 2013, URL: http://www.china.org.cn/china/2013-04/26/content_28668480.htm
5) Rui C. Barbosa, "China back in action with Long March 2D launch of Gaofen-1," NASA Spaceflight.com, April 25, 2013, URL: http://www.nasaspaceflight.com/2013/04/china-back-in-action-long-march-2d-gaofen-1/
6) David Dickinson, "Space Debris: A Tale of Two Satellites," Universe Today, July 23, 2013, URL: http://www.universetoday.com/103650/space-debris-a-tale-of-two-satellites/
7) "Ecuador's only satellite may have been damaged in space collision," Space Daily, May 23, 2013, URL: http://www.spacedaily.com/reports/Ecuadors_only_satellite_may
8) "Ecuador warns satellite could hit rocket remains," Space Daily, May 22, 2013, URL: http://www.spacedaily.com/reports/Ecuador_warns_satellite_could_hit_rocket_remains_999.html
9) Ronnie Nader, Hector Carrion, Manuel Uriguen, "The Ecuadorian experience in space: The NEE satellite constellation," Proceedings of the 65th International Astronautical Congress (IAC 2014), Toronto, Canada, Sept. 29-Oct. 3, 2014, paper: IAC-14,B4.1.11
11) "Two TV CubeSats from Ecuador," Southgate, Feb. 14, 2013, URL: http://www.southgatearc.org/news/february2013/two_tv_cubesats_from_ecuador.htm#.UZNCM0pWIRo
12) Ronnie Nader, Hector Carrion, Manuel Uriguen, "Argos: Hyper amplification manifold for enhancing ground station reception," Proceedings of IAC 2011 (62nd International Astronautical Congress), Cape Town, South Africa, Oct. 3-7, 2011, paper: IAC-11-B2.1.10, URL: http://www.exa.ec/trabajos/10065%20-%20ARGOS%20-%20HYPER%20AMPLIFICATION%20MANIFOLD
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).