PhoneSat-2.5 Demonstration Mission
PhoneSat-2.5, a 1U CubeSat with a mass of ~1 kg, was developed at NASA/ARC (Ames Research Center) in Moffett Field, CA. It is the fourth in a series of missions designed to use commercially available smartphone technology as part of a low-cost development for basic spacecraft capabilities. The technology demonstration is a pathfinder for the EDSN (Edison Demonstration of Smallsat Networks) and will collect data on the long-term performance of consumer technologies used in spacecraft.
Figure 1: Illustration of the PhoneSat-2.5 CubeSat (image credit: NASA/ARC)
PhoneSat 2.5 builds upon the successful flights of previous NASA smartphone satellites launched in 2013.
• Two PhoneSat-1.0 satellites were launched on April 21. 2013 with the maiden flight of the Antares-110 vehicle of OSC (Orbital Sciences Corporation) along with a prototype of the PhoneSat-2 satellite that featured a number of upgrades including the use of solar panels for power generation, a two-way radio link and upgraded avionics.
• PhoneSat 2.4 was launched on November 20, 2013 and achieved its primary mission objectives, demonstrating a smartphone can serve as an avionics controller. It also demonstrated the use of its magnetometer and an Ames-designed magnetorquer to actively align the satellite's orientation with Earth's magnetic fields. This was a first for Ames small satellites, which to date have used passive, permanent magnetic torque rods.
As of March 2014, PhoneSat 2.4 continues to transmit data, which means its solar arrays, battery charging circuit, Arduino watchdog and data router are still operating correctly. In early January, however, the Phonesat 2.4 smartphone began to experience recurring resets coinciding with a period of numerous solar flares. As a result, the satellite no longer executes flight application software. 1)
The PhoneSats feature smartphones running the Android operating system and build the centerpiece of the 1U Cubesats. The main purpose of the phones is to control all critical functions of the satellite, determine its attitude with the phone's sensors, store data, provide acceleration data and take images of Earth with the 5 Mpixel camera of the phone. PhoneSat 2 is built around the Samsung Nexus S phone as the onboard computer. The large memory, fast processors, high-resolution cameras, GPS receivers, gyroscopes and magnetometer sensors common in smartphones make them excellent tools to use in space. PhoneSat-2.5 is equipped with power-generating solar cells. The spacecraft features a two-way S-band radio, allowing commanding from Earth. A GPS receiver provides position data and reaction wheels are used for active attitude control with orientation data being provided by the phone. 2)
PhoneSat 2.5 sets out to complete a more ambitious mission than the previous PhoneSats. The satellite will continue to provide further confidence in the PhoneSat concept and components by investigating its ability to survive long-term in the radiation environment of space. Also, the satellite will continue the technical demonstration of using smartphone technology to complete attitude control, data handling, and communication (Ref. 2).
In addition, PhoneSat 2.5 will test a space-based communications system supported by the smartphone for potential future application. The satellite is equipped with a higher-gain S-band antenna that will serve as a pathfinder for future missions such as the EDSN (Edison Demonstration of Smallsat Networks) of NASA planned to launch in 2014.
EDSN will use the PhoneSat architecture and deploy eight identical satellites (1.5 CubeSats) in a loose formation to demonstrate cross-link communications in between the satellites to allow engineers to study the application of small satellites in space-to-ground and space-to-space communications. 3)
As an upgrade to previous PhoneSats, the 2.5 CubeSat uses an active attitude determination and control system utilizing reaction wheels to provide three-axis control and precise pointing capability. This will serve as a demonstration to determine whether small satellites could be used to carry scientific instruments that require precise pointing to fulfill their function.
With an expected orbital life time of about six weeks, PhoneSat 2.5 will further study the capabilities of the satellite design in the harsh radiation environment of LEO (Low Earth Orbit).
PhoneSat 2.5 is equipped with a higher-gain S-Band antenna, which serves as a pathfinder for future NASA missions, including the EDSN mission. The two-way S-band radio allows engineers at SCU (Santa Clara University) in Santa Clara, CA to control PhoneSat-2.5 from Earth.
PhoneSat 2.5’s smartphone camera will attempt to transmit photographs to the ground station at Santa Clara University in California to gather information for future low-cost star trackers. The PhoneSat series of technology demonstration missions is funded by the Small Spacecraft Technology Program, in NASA’s Space Technology Mission Directorate at NASA Headquarters and the Engineering Directorate at Ames.
Launch: The PhoneSat-2.5 1U CubeSat is part of the secondary payloads on the resupply space transport mission to the ISS, the CRS-3 (Cargo Resupply Services-3) Falcon-9v.1.1 mission launched on April 18, 2014 of SpaceX. The launch site was Cape Canaveral, FL. 4) 5)
Orbit: Near-circular orbit, altitude of ~400 km of the ISS, inclination =51.6°.
Secondary payloads: The secondary payloads (4 nanosatellites and 1 CubeSat) were contained in four P-PODs (Poly Picosatellite Orbital Deployers) and installed on the second stage of the Falcon-9 launcher. These secondary payloads were not being delivered to the ISS, but released from their P-PODs following the separation of the Dragon capsule from the second stage of Falcon-9. The insertion orbit of the secondary payloads was at an altitude of ~325 km with an inclination of ~ 51.6º.
The secondary payloads were part of the fifth installment of NASA's ELaNa (Educational Launch of Nanosatellite) mission. Over 120 students have been involved in the design, development and construction of all the CubeSats that were flown as auxiliary payloads on the SpaceX-3 cargo resupply mission to the International Space Station. 6)
• KickSat, a 3U CubeSat of Cornell University, N.Y., USA. KickSat will carry and attempt to deploy about 250 femtosatellites into LEO (Low Earth Orbit).
• All-Star/THEIA, a 3U CubeSat of COSGC (Colorado Space Grant Consortium).
• SporeSat, a 3U CubeSat (~5.5 kg) developed through a partnership between NASAs Ames Research Center and the Department of Agricultural and Biological Engineering at Purdue University. SporeSat will be used to conduct scientific experiments to gain a deeper knowledge of the mechanisms of plant cell gravity sensing.
• TSAT (TestSat-Lite), a 2U CubeSat developed at Taylor University of Upland, Indiana. The objective is to perform measurements of the temperature and density of the plasma in the near-Earth space environment.
• PhoneSat-2.5, a technology 1U CubeSat of NASA/ARC to continue technology demonstrations of the PhoneSat CubeSat series.
• PhoneSat 2.5 has been successfully deployed from the SpaceX Falcon 9 rocket and is now in orbit. The satellite is operational and is sending beacon packets.
1) “NASA's Latest Smartphone Satellite Ready for Launch,” NASA, March 13, 2014, URL: http://www.nasa.gov/content/nasas-latest-smartphone-satellite-ready-for-launch/#.U0P6O6KegkA
2) Patrick Blau, “PhoneSat-2.5,” Dragon SpX-3 Cargo Overview, Spaceflight 101, URL: http://www.spaceflight101.com/dragon-spx-3-cargo-overview.html
3) Deborah Westley, “Edison Demonstration of Smallsat Networks (EDSN),” NASA, May 3, 2013, URL: http://www.nasa.gov/directorates/spacetech/small_spacecraft/edsn.html#.U0QRDaKegkA
6) “ELaNa V CubeSat Launch on SpaceX-3 Mission,” NASA Facts, March 2014, URL: http://www.nasa.gov/sites/default/files/files/ELaNa-V-Factsheet-508.pdf
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) .