Submission

High-Speed Secure Satellite Comms. for Extrication

Show a 2-m inflatable Ka-band communication antenna (2U payload) within a 6U GEO CubeSat that provides 500 Kb/s data rate for military use.

Jekan Thangavelautham is an Assistant Professor and has a background in aerospace engineering from the University of Toronto. He worked on Canadarm, Canadarm 2 and the DARPA Orbital Express missions at MDA Space Missions. Jekan obtained his Ph.D. in space robotics at the University of Toronto Institute for Aerospace Studies (UTIAS) and did his postdoctoral training at MIT's Field and Space Robotics Laboratory (FSRL). He has 60+ peer-reviewed publications, 7 inventions and patents and has won numerous awards including the Popular Mechanics Breakthrough Award in 2016, Top 5 in Aerospace/Defense in the Tech Brief Design the Future Contest 2017 and has been a co-author on several student best paper awards.

Jekan Thangavelautham heads the Space and Terrestrial Robotic Exploration (SpaceTREx) Laboratory at University of Arizona. His research group focuses on research and demonstration of game-changing technologies funded by AFRL, NASA, NASA JPL, NSF and the Intelligence Community. The group has in-house capacity to conceptualize, design, manufacture and operate research payloads, CubeSats and small-satellites. Current research focus includes CubeSat/small sat systems engineering, interplanetary missions and advanced concepts, coupled with fundamental research in enabling technologies spanning communications, power, propulsion, thermal control and autonomous control of swarms.

A highlight of SpaceTREx achievements to date are presented below:
• SpaceTREx was selected by AFRL to design a CubeSat to monitor space threats, including incoming meteors and space-weather.
• SpaceTREx develops inflatable antenna tech. in close collaboration with NASA JPL’s Communications Group
• SpaceTREx develops control technologies for spacecraft swarms with NASA JPL’s Communications Group
• SpaceTREx was selected for advanced concept design of a CubeSat to Europa by NASA JPL. The team has experience designing CubeSats for high-radiation and for advanced imaging.

University of Arizona's SpaceTREx Laboratory is borne out of a culture of innovation and dedication. The team at SpaceTREx believes they have the right attitude, expertise, program management experience, educational background and world-class facilities to produce a solution that is state-of-the-art for CubeSats and has game-changing applications for the sponsor.

SpaceTREx is a systems engineering research group. SpaceTREx engages with sponsors when the group believes the problem at hand is a ‘systems problem.’ In a ‘systems problem,’ the fundamental technologies may already exist, but it is the assembly and integration that is unique and that may bring whole new capabilities. Systems thinking allows for holistic analysis of the problem at hand, including accounting not just for the technology, but the integrated design, control, the human factors, workplace culture, field conditions, budget, schedule and developmental risks.

The SpaceTREx laboratory often works with a diverse range of sponsors from government to industry. SpaceTREx believes in life-long learning and actively engages with the sponsor and listens, to determine their motivations, culture and expectations. Where possible the group embeds with the sponsors (in the field) to get a thorough understanding of the problems at-hand and solutions. Team personnel do internal filtering to present exceptional options. The research group is willing to work with the sponsor at every step of the process to ensure success. SpaceTREx submits to regular reviews, site visits and presentations of new ideas that may have applications or enhance an existing project.

SpaceTREx has the technical expertise to successfully execute this project and is one of the few groups at the University of Arizona that takes a laboratory demonstrated technology and applies it in the field. SpaceTREx personnel are experts in CubeSat design, development and operations. They have presented dozens of peer-reviewed publications at major technical conferences and are well known in the technical community. . SpaceTREx student personnel graduate and are emerging leaders at well-known aerospace, defense, government and academic institutions. Depending on the circumstances, SpaceTREx also works effectively with other laboratories and institutions on larger projects. The team is also well connected with leaders in the aerospace and defense industry and can assemble expert teams as needed to tackle complex problems.

The laboratory and its personnel have produced solutions for the DoD, mining industry, aerospace industry, NASA, other space agencies including the Canadian Space Agency and European Space Agency. SpaceTREx's engineering personnel include its head, Prof. Thangavelautham who has over 17 years of experience working in the space industry, together with a top-notch team of PhD students and Master’s students. Prof. Thangavelautham has worked in different capacities on projects ranging from DARPA's Orbital Express mission that demonstrated on-orbit servicing of satellites to field demonstration of autonomous robots for resource mining destined for the Moon. The team is well rounded with expertise in every critical aspect of CubeSat and small-sat conceptualization, design, development and operation. Critical to this challenge, the team has world-class expertise in understanding and designing for the space environment, including designing for the space radiation environment, design of precise attitude control systems, thermal control and communication systems. The team also has the tools for testing, verification and integration of CubeSats.

The team has the capacity to prototype and demonstrate critical elements of the proposed system in a matter of months in the laboratory. Furthermore, the team can produce a detailed design and work with the sponsor to quantify and predict system performance in the field . The team will also utilize world-class resources of the Lunar and Planetary Laboratory at University of Arizona for testing, in addition to support from the newly formed Defense and Space Research Institute (DSRI) at Univ. of Arizona for this project. DSRI will provide program management support for SpaceTREx, in addition to providing in-house defense experts. Finally, SpaceTREx is actively working with a commercial partner on an Airforce-funded project to develop thermal control system solutions for a high-power communications device on a CubeSat.

Special Forces in the field benefit from satellite phone communication providing the ability to contact operational command anywhere in the world. However, present commercial satellite phones provide a low data rate of 10 Kbps which is sufficient for voice communication. The system is too slow to communicate high-resolution video or extricate data from high-bandwidth ground networks. These satellite phones are commercially available and can be jammed or eavesdropped by a determined enemy. We propose demonstration of a 6U state-of-the-art GEO CubeSat communication system that utilizes an inflatable Ka-band antenna to directly communicate with a Special Forces ground team. This spacecraft can communicate with a ground team at 500 Kbps or more. The primary purpose of the satellite is to extricate and store data from ground sources onto the satellite. An extension to this concept is to combine two inflatable antennas onto the satellite enabling the spacecraft to relay to a more capable military communications satellite. This technology allows increased data rates of 50x compared to a satellite phone. Furthermore, data may be transferred to this CubeSat where it is stored and fully interrogated for threats before being relayed to a secure military network.

The team has been developing inflatable communication antenna technology for the past 4 years in close collaboration with NASA JPL. The technology is fundamentally robust and utilizes a simple chemical reaction to deploy the antenna. The spherical antenna is hardened using a UV curing process and is not susceptible to micrometeorites or space debris. Inflatables offer the best stowage to deployment volume, with a 20x advantage in terms of mass and volume over conventional Kevlar antennas and nearly 5x advantage over deployable umbrella antennas. A demonstrator would consist of a 6U GEO CubeSat that utilizes hardware that is readily available and would be integrated with the inflatable antenna system.

The proposed solution is expected to be a 2U payload (20 cm x 10 cm x 10 cm), with a mass of up to 2.6 kg and mounted within a 6U CubeSat. The payload consists of two major components, a inflatable antenna package and a Ka-band transponder. This payload will enable deployment of a 2 meter diameter spherical Ka-band antenna in orbit after launch. Following inflation in orbit, the antenna skin will harden under sunlight (UV exposure) over 6 hours. Depending on sponsor needs, the antenna maybe further increased to 3-5 m for a small increase in payload mass.

Further details on the design is available but withheld from public disclosure.

The proposed communications technology would provide a significant boost to the operational capabilities of a Special Forces team operating covertly in a remote corner of the planet. By increasing the effective communication bandwidth, the proposed CubeSat could have one of several roles including, a primary role as a device to extricate, collect and analyze large quantities of digital data in a secure location.

A second role is for the satellite with an additional inflatable antenna to act as a high-speed communication relay without using current military communication networks. A third role includes use of the satellite to act as a mini autonomous command center for the ground forces. While a fourth role is for the satellite to operate as an off-site mini super-computer platform in space. This resource would be used to process photos and video data in support of complex field missions. All four roles increases the effectiveness of the Special Forces, acts as a force multiplier while reducing the vulnerability of the ground team.

Thanks to the high-data bandwidth possible, the Special Forces can quickly and effectively extricate data offsite onto the satellite instead of carrying the highly prized data with them. Carrying the data is of concern if the group is inadvertently captured or if it has to pass through a friendly third party that may inadvertently eavesdrop or intercept. This approach enables for the Special Forces to deny any knowledge of sensitive operations and thus reduces risk to themselves in case of capture. Extricating the data off-site also allows for further analysis off-site without being vulnerable to interception. The analysis tools maybe highly guarded and hence needs to be away from the operational theater.

There is a important advantage for the Special Forces team to travel light so that the team is nimble and minimize resource use on the ground. Certain types of technical analysis if done in the field may provide major tactical advantages but may consume significant resources in terms of computational power and energy required that may make a Special Forces team vulnerable to detection in the field. If the team were to use an equivalent field device then it would require carrying lots of batteries or a photo-voltaics recharging center which adds to the carry-mass and makes the team more vulnerable to detection. Another consideration is that the extricated data maybe booby trapped by the enemy with viruses, spyware and exploits to alert the authors that the data has been compromised. Therefore, the collected data needs to be carefully interrogated using relatively low-cost hardware instead of risking uploading the data to a military network.

Utilizing this system as a high-bandwidth communication relay, the link permits transfers of high-resolution videos, photographs and other sensor data. This permits an off-site command center to obtain timely data from the field and make informed decisions. Higher resolution images, video and other sensor data can help the off-site command center to increase the effective perimeter around the Special Forces team by actively working together to identify field threats.

The high-data bandwidth can also be an enabler for autonomous support for the Special Forces. This would require the ground forces 'pipe' video and camera data from their equipment directly to the satellite platform, which then identifies risks and threats, provides timely threat alerts to the team and other services including voice (language) translation, background research and field expertise. The ability to provide timely threat alerts for a Special Forces team can enable the team to rest and be more resourceful for a mission at hand. This approach effectively increase eyes and ears on the ground and is in effect a 'defensive force multiplier.'

While these services maybe carried in hand in the form of a portable device, there is a significant advantage to having this technology operate off-site in-case of eavesdropping, interception or capture. A fourth supporting role for this satellite platform is to perform computation in support of vision processing, handwriting matching and other challenging computation and vision tasks in the field. The algorithms for these tasks maybe highly prized and therefore an effective risk-mitigation strategy is to avoid deployment of these devices in the field and instead use remotely operating high-bandwidth satellites.

The proposed system architecture would utilize a hierarchical, compartmentalized security scheme to mitigate risk of intrusion. If a ground terminal is compromised, the spacecraft maybe locked or go into stealth mode to prevent intrusion or be disabled to limit further risks. In the unlikely event that the spacecraft is compromised, it too can be locked out from the main military communications network and critical functions disabled.

The payload will require 25-30 Watts for a demonstration lasting xx minutes.
The payload will require xx Watts for prolonged operation.
The payload can operate in sleep mode consuming less than 5 Watts.
The payload will rely on a standardized bus voltage and current rating.

Note: More details are available but withheld from public disclosure.

The payload will need to remove up to 30 Watts of thermal power for a demonstration lasting xx minutes.
The payload will need to remove xx Watts of heat for prolonged operation.
The payload will require a thermal switching interface to remove heat built up during operations.

The electrical interface to the communication transponder will be a standard high-bandwidth interface.
Data transfer rates between devices of 5-10 MBps will be supported, though the actual communication data rate with ground will be lower.
In a LEO demonstration, data rate of 1 MBps will be targeted, while in GEO it will be 500 Kbps.

Detailed link margin and data analysis are available but withheld from public disclosure.

In LEO, demonstration will produce a minimum 8-minutes pass where 60 MB is uploaded from ground to spacecraft per orbit.
Continuous link from LEO will result in 680 MB data downloaded to ground over a single 90 minute orbit.
The payload will benefit from having gigabytes of data storage on the spacecraft to perform detailed and extended tests.
For operational demonstration in GEO, data can be uploaded or downloaded at 225 Megabytes/per hour.

The demonstration can be accommodated using an off-the-shelf attitude determination and control package with xx degrees pointing accuracy.

Payload can be fully accommodated using one of several American manufactured 6U CubeSat bus kits.

Note: Specific details available but withheld from public disclosure.

Physical cut-out modifications will need to be made to a 6U commercial CubeSat bus to enable deployment of the inflatable antenna.
A secondary engineering camera would need to be installed to observe and record the inflation process in orbit.

The proposed prototype of a Ka-band inflatable communications antenna package has undergone rigorous internal reviews and a multi-year research and development effort. It has undergone extended laboratory tests using a laboratory vacuum chamber and has undergone extensive testing of antenna performance using an anechoic chamber. However, this technology has not been deployed on a CubeSat in space. The latest design can be manufactured entirely from off-the-shelf parts and will have Ka-band capability. What will be truly unique and innovative is the integration of this brand-new technology for application by the Special Forces. The elegance in the design is that it relies on a simple kitchen-counter chemical reaction to inflate an antenna that can provide a 50 dB antenna gain.

The reliance on a simple chemical reaction avoids complex, unreliable mechanisms in space. Inflatables have been proven to be a reliable technology in space. NASA in the 1960s demonstrated the Echo I and II inflatables as passive relays for microwave communication. These systems operated flawlessly for more than 5 years. NASA JPL has demonstrated the utility and reliability of inflatables as landing bags on several high-profile, half a billion dollar Mars missions. The proposed technology is at a Technology Readiness Level (TRL) 4.5 and can be made ready for a flight within 24 months.

The proposed design will require additional testing for demonstration on a CubeSat mission. We envision demonstration of the system on a high-altitude balloon platform, combined with more details tests in our large vacuum chamber to replicate on-orbit conditions as part of a 24-month plan to prepare the technology for launch. A first in space demonstration mission would occur in Low Earth Orbit (within 24 months), followed by a operational demonstration mission in Geo-Stationary Orbit within 36 months from now.

Yes