ALICE (AFIT LEO iMESA CNT Experiment)
ALICE is the first nanosatellite of AFIT (Air Force Institute of Technology), an Air Force graduate engineering school at the Wright Patterson Air Force Base (WPAFB) in Ohio. The objective is to test the performance of a pair of advanced CNT (Carbon Nanotube) arrays for a potential propulsion system for nanosatellites. The nanotubes were produced using a new manufacturing process developed in partnership at AFIT, AFRL (Air Force Research Laboratory), and the GTRI (Georgia Tech Research Institute). 1) 2)
Figure 1: Artiist's view of the deployed ALICE nanosatellite (image credit: AFIT)
ALICE is a 3U CubeSat supplied by the NRO (National Reconnaissance Office) Colony CubeSat program (bus manufacturer: Pumpkin Inc.). The 3U CubeSat with a C1B (Colony I bus) on Pumkin's CubeSat Kit (CSK) architecture has a size of 10 cm x 10 cm x 34 cm and a mass of ~ 5 kg. The nanosatellite is equipped with four deployable solar arrays and body-mounted panels to supply power for a number of technical demonstrations carried out aboard the vehicle. 3)
ALICE was designed, tested, and integrated at AFIT by a multi-department team of professors, students, and technicians. The team is comprised of military officers and civilians, and includes students from local southwest Ohio universities. The partnership with GTRI and USAFA provided students in each institution an opportunity to participate in ground-breaking research with the potential to impact numerous future satellites employing electric propulsion.
The ALICE mission will be controlled by a ground station at AFIT. It represents an end-to-end space mission design, build and fly capability and is the first of many such flights planned by AFIT’s newly formed Center for Space Research and Assurance.
Launch: ALICE was launched as a secondary payload on December 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). 4) 5) 6) 7)
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. 8) 9)
Secondary payloads: Next to the NROL-39 primary payload, the Atlas-5 hosts the GEMSat/ELaNa-2 mission (secondary payloads) for the NRO and the NASA/LSP ( Launch Services Program), lifting 12 CubeSats/nanosatellites to orbit as secondary payloads. 10) 11)
• 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 2 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. 12)
Figure 2: 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. 13)
Sensor complement: (iMESA, CNT)
Utilizing a multi-departmental team, AFIT engineers in the Electrical Engineering Department developed a payload to directly expose the CNT (Carbon Nanotube) arrays to the space environment while protecting an identical control array within the satellite. The arrays, which are approximately 1 cm2 in size, will be switched on and off and their behavior studied. The payload experiment utilizes a sensor device known as iMESA (Integrated Miniaturized Electromagnetic Analyzer), designed by engineers at the U.S. Air Force Academy (USAFA) in Colorado Springs, CO.14)
The iMESA device has a mass of 150 g and a power requirement of 0.5 W. iMESA is being used to measure the number and speed of electrons that get produced by the CNT arrays.
Figure 4: Photo of the test equipment on the ALICE nanosatellite (image credit: AFIT)
The carbon nanotube arrays are excellent conductors and their geometry makes them ideal electron emitters. Researchers at the Georgia Tech Research Institute (GTRI) produced the CNT arrays using unique technology that grows bundles of vertically-aligned nanotubes embedded in silicon chips. In future versions of electrically-powered ion thrusters, electrons emitted from the carbon nanotube tips may be used to ionize a gaseous propellant such as xenon. The ionized gas would then be ejected through a nozzle to provide thrust for moving a satellite in space.
The satellite payload is highlighted by a pair of carbon nanotube arrays that will be used to demonstrate carbon nanotubes as electron emitters for future spacecraft propulsion that would use the generated electrons to ionize gaseous propellant for ejection. Each CNT array is about 1 cm2 in size and contains as many as 50,000 nanotubes.
Figure 5: Photo of a chip, designed and built by GTRI, which is covered with bundles of vertically-aligned nanotubes (image credit: GTRI)
Existing ion thrusters rely on thermionic cathodes, which use high temperatures generated by electrical current to produce electrons. These devices require significant amounts of electricity to generate the heat, and must consume a portion of the propellant for their operation.
If the CNT arrays can be used as electron emitters, they would operate at lower temperatures with less power — and without using the limited on-board propellant. That could allow longer mission times for satellites, or reduce the weight of the micropropulsion systems.
Figure 6: Jud Ready, a principal research engineer at GTRI, holds a chip containing bundles of carbon nanotubes grown in pits (image credit: Georgia Tech)
1) “AFIT’s first satellite slated to launch by end of year,” AFIT, July 22, 2013, URL: http://www.afit.edu/PA/news.cfm?article=585&a=news
2) Joshua Debes, Nathan Howard, Ryan Harrington, Richard Cobb, Jonathan Black, “Rapid Build and Space Qualification of CubeSats,” Proceedings of the 25th Annual AIAA/USU Conference on Small Satellites, Logan, UT, USA, Aug. 8-11, 2011, paper: SSC11-VII-7, URL: http://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1148&context=smallsat
3) Andrew E. Kalman, Adam W. Reif, Jerami M. Martin, “MISC-3 - The next generation of 3U CubeSats,” CubeSat Developers' Summer Workshop, Logan, Utah, USA, Aug. 10-11, 2013, paper:SSC13-WK-37, URL: http://digitalcommons.usu.edu/cgi/viewcontent.cgi?filename=0&article=2898&context=smallsat&type=additional
5) William Graham, “Atlas V launches NROL-39 from Vandenberg,” NASA Spaceflight.com, Dec. 5, 2013, URL: http://www.nasaspaceflight.com/2013/12/atlas-v-launch-nrol-39-vandenberg/
6) Stephen Clark, “Government spy satellite rockets into space on Atlas 5,” Spaceflight Now, Dec. 6, 2013, URL: http://www.spaceflightnow.com/atlas/av042/131206launch/#.UqHYgCeFdm4
7) NROL-39, United Launch Alliance Atlas V Rocket Successfully Launches Payload for the National Reconnaissance Office,” ULA, Dec. 6, 2013, URL: http://www.ulalaunch.com/site/pages/News.shtml#/163/
8) “Future Imagery Architecture,” Wikipedia, URL: http://en.wikipedia.org/wiki/Future_Imagery_Architecture
9) William Graham, “Atlas V launches NROL-39 from Vandenberg,” NASA Spaceflight.com, Dec. 5, 2013, URL: http://www.nasaspaceflight.com/2013/12/atlas-v-launch-nrol-39-vandenberg/
10) Patrick Blau, Atlas V to launch with classified NROL-39 & 12 CubeSats in December, Nov. 15, 2013, URL: http://www.spaceflight101.com/atlas-v-nrol-39-launch-updates.html
12) “Atlas V GEMSat Launch 2013,” URL: http://www.cubesat.org/index.php/missions/upcoming-launches/134-l39-launch-alert
14) “Carbon Nanotube Field Electron Emitters Will Get Space Testing,” Georgia Tech Research Institute, Nov. 13, 2013, URL: http://gtri.gatech.edu/casestudy/carbon-nanotube-field-electron-emitters-will-get-s
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.