Category: Target: Earth

ALICE is the first nanosatellite developed by the Air Force Institute of Technology (AFIT), an Air Force graduate engineering school at the Wright Patterson Air Force Base (WPAFB) in Ohio. The primary goal of ALICE is to evaluate a pair of advanced Carbon Nanotube (CNT) arrays as a proposed propulsion system for nanosatellites. The nanotubes in question were developed in partnership with AFIT, Air Force Research Laboratory (AFRL), and the Georgia Tech Research Institute (GTRI).

ALICE is a 3U CubeSat provided by the National Reconnaissance Office (NRO) Colony CubeSat program . The 3U CubeSat is rated at a size of 10 cm x 10 cm x 34 cm and a mass of ~ 5 kg. The bus is a Colony 1 class bus manufactured by Pumpkin Incorporated. The CubeSat is equipped with four deployable solar arrays which run the length of the bus along with body-mounted panels to supply power for the sensor compliment and testing payload.

ALICE was assembled, fabricated, and tested at AFIT by a multi-department team of professors, students, and technicians. The team was comprised of both military personnel and civilians, and included students from many Ohio universities. GTRI and USAFA also provided students in each institution the opportunity to participate in the development of new spacefaring technologies and contribute to the future of electric propulsion.

The ALICE mission is controlled by an independent ground station at AFIT. This effort by AFIT comprises and end-to-end mission plan and is the first of many planned in the coming years.

Launch:

ALICE was contained as a secondary payload on December 6, 2013 aboard an Atlas-5-501 launch vehicle from Vandenberg Air Force Base, CA. The primary payload on this flight was the classified NROL-39reconnaissance mission of the National Reconnaissance Office. The launch provider was the United Launch Alliance.

Sensors and Payload:

Engineers in the Electrical Engineering Department at AFIT developed a unique payload to directly expose the Carbon Nanotube arrays to the space environment while protecting an identical control array within the satellite. The arrays, which are each approximately 1 square cm in size, can be  controlled from the AFIT ground station to study their behavior when both active and inactive. The payload experiment utilizes a design from engineers at the U.S. Air Force Academy (USAFA) to measure the number and speed of electrons produced by the CNT arrays. This sensor device is known as iMESA (Integrated Miniaturized Electromagnetic Analyzer) and has a mass of 150 g and a power requirement of 0.5 W.

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 square cm in size and contains as many as 50,000 nanotubes.

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.

Sources and Additional Information:

1. https://space.skyrocket.de/doc_sdat/alice.htm
2. https://www.n2yo.com/satellite/?s=39467
3. https://directory.eoportal.org/web/eoportal/satellite-missions/a/alice
4. https://nssdc.gsfc.nasa.gov/nmc/spacecraft/display.action?id=2013-072F

Acronym	ALICE
Full Name	AFIT LEO iMESA CNT Experiment
Size	3U
Status	Active
Launch Date	December 6th, 2013
NORAD ID	39467
Downlink Frequency	460.xxx (MHz)

The ISS Orlan antenna designed and built at Georgia Tech Research Institute offered a unique new form for antennas.  The 2 ft towel shaped antenna doubles as a handrail and allows for communication between suited astronauts within the airlock and the rest of the crew on board.  The ISS Orlan antenna was especially designed to work with Russian spacesuits, which at the time of launch operated on an unusual frequency that barely resonated within the airlock and contained no antennas of their own. The ISS Orlan antenna can also withstand huge temperature swings and forces experienced when space packs hit it.

Craft Overview:

The 2 ft towel bar antenna was built using a special “loop” design that couples a sufficient amount of RF energy tot he astronaut, instead of reflecting the energy off the walls of the airlock.

Deployment:

The ISS Orlan antenna launched as part of the STS-104 mission, where Shuttle Atlantis delivered the completed airlock to the ISS in July of 2001.

Sources and Additional Information:

1. https://smartech.gatech.edu/bitstream/handle/1853/8758/40%20Departments.pdf?sequence=1&isAllowed=y
2. https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=883504
3. https://www.militaryaerospace.com/home/article/16707591/georgia-tech-develops-space-antenna

Name	ISS Orlan Antenna/ISS Airlock Handrail Antenna
Size	2 ft
Status	Active
Launch Date	July 2001
Principal Investigator	Victor Tripp

The Long Duration Exposure Facility was a free structure implemented to take full advantage of the two way transportation capability of the Space Shuttle program. This satellite consisted of a number of technological experiments designed to collect information about long term exposure to the conditions of space and to collect information on the overall environment in low earth orbit (LEO). Among the topics and areas explored by LDEF were changes in material properties over time in the space environment, performance tests of spacecraft systems, component evaluations for spacecraft power, and chemical experiments in crystal growth.

Craft Overview:

The LDEF spacecraft was an open-grid, 12-sided, cylindrical structure on which a series of rectangular trays used for mounting experiment hardware were attached. The cylinder was 9.1 m in length and 4.3 m in diameter. LDEF was a gravity-gradient stabilized spacecraft, the longitudinal axis was pointing toward the center of the Earth. Surface elements were fixed relative to LDEF’s velocity vector. Magnetic actuators controlled the rotation around the longitudinal axis. The LDEF structure was configured with 72 equal-size rectangular openings on the sides and 14 openings on the ends (six on the Earth-facing end, and eight on the space-facing end) for mounting experiment trays. The craft’s total mass of spacecraft at deployment was 9,710 kg.

LDEF had no central power or data system; however, provide initiation and termination signals at the start and end of the mission. Any required power and/or data systems were included by the experimenter in each respective tray.

Deployment:

The LDEF was launched on the Challenger Space Shuttle (Shuttle STS-41-C) on April 6, 1984 from Cape Canaveral, FL, USA. The payload was deployed one day later on April 7th once Challenger reached the desired orbit. Upon deployment it was placed in a nearly circular orbit with average altitude of 477 km and inclination of 28.5 degrees. Over the nearly 6 year lifetime of the craft the orbit was seen to decay by over 100 km to 335 km when retrieved.

Recovery and Results:

Due to delays caused by the Challenger accident (STS-25), LDEF was finally recovered 69 months after launch on January 12, 1990 (STS-32) by the Space Shuttle Columbia. The Shuttle approached LDEF in such a way as to minimize possible contamination to LDEF from thruster exhaust. While LDEF was still attached to the RMS arm, an extensive 4.5 hour photo survey was performed that included photographs of each individual experiment tray, as well as larger areas of the craft. Special efforts were undertaken to ensure protection against contamination of the payload.

As a consequence of the delayed retrieval from orbit, much more data had been gathered than planned. Post mission de-integration occurred in the Spacecraft Assembly and Encapsulation Facility-II at NASA/KSC.

Sources and Additional Information:

1. https://directory.eoportal.org/web/eoportal/satellite-missions/l/ldef
2. A. S. Levine (editor), “LDEF – 69 Months in Space, First Post-Retrieval Symposium,” NASA Conference Publication 3134 (Part 1 and Part 2), Proceedings of a symposium sponsored by NASA at Kissimmee, Florida, June 2-8, 1991
3. “The Long Duration Exposure Facility (LDEF), Mission 1 Experiments,” 1984. NASA SP-473, edited by L. G. Clark, W. H. Kinard, D. J. Carter Jr., J. L. Jones Jr., URL: http://ia600507.us.archive.org/1/items/nasa_techdoc_19840016564/19840016564.pdf
4. “LDEF,” NASA/LaRC, URL: http://setas-www.larc.nasa.gov/LDEF/index.html
5. W. K. Stuckey, “Lessons learned form the Long Duration Exposure Facility,” Feb. 15, 1993, URL: http://www.dtic.mil/cgi-bin/GetTRDoc?AD=ADA266026
6. https://www.nasa.gov/centers/marshall/history/ldef01.html

Acronym	LDEF
Full Name	Long Duration Exposure Facility
Size	9.1 meters x 4.3 meters
Status	Recovered and Retired
Launch Date	April 7th, 1984