Dr. Janson

NASA’s Innovative and Advanced Concepts (NIAC) group funded a 9-month long Phase I study on active membrane spacecraft, called Brane Craft, in early 2016. This concept uses ~10-micron thick Kapton sheets as the basic spacecraft structure, with a 10 to 30-micron wide gap between the sheets serving as a propellant tank. The propellant is an ionic liquid and the Brane Craft uses distributed nano-electrospray thrusters for propulsion. The current 1-meter square design has a total thickness of 50 microns, and a mass of only 81 grams, wet. Thin film solar cells provide up to 180 W of power to the 4000-s specific impulse electric thrusters, resulting in 8.2 mN of thrust for an unprecedented acceleration of up to 0.1 m/s² at this high specific impulse.   Total delta-V is 16 km/s, enabling a Brane Craft to visit most bodies in the solar system, and return. Total operating time for the thrusters, under full power, is only 36 hours. The target application for this spacecraft architecture is orbital debris removal. An 81-gram mass Brane Craft starting from the International Space Station can remove objects up to 2-kg in mass up to 1000 km in altitude, and up to 1 kg in mass up to 2000-km altitude. If we were to use current spacecraft technologies, the debris removal spacecraft would be two orders-of-magnitude heavier.   The proposed process starts with waiting until the Right Ascension of the Ascending Node for both the starting orbit and the target orbit match, followed by several hours of thrusting and coasting to match orbits, followed by a few days of orbit rephasing, followed by a few days of rendezvous. The Brane Craft then wraps itself about the debris object, and thrusts in a retrograde direction over 1 to 10 days to lower altitude to 250 km where atmospheric burnup occurs in a few days. Required technologies, which are discussed, include nano-electrospray thrusters, thin-film solar cells, thin film electronics, thin film antennas, thin film attitude and navigation sensors, thin film magnetic actuators, and thin film electroactive actuators for shape control.  Mission and space environmental analyses have shown that the main challenges are electronics, solar cell, and sensor design for multi-megarad radiation tolerance due to ~10-micron thick radiation shielding, and the ability to withstand ~50 micrometeoroid/orbit debris penetrations over a one-month long mission life.

Biography:

Dr. Siegfried Janson is a senior scientist in the Space Science Applications Laboratory at The Aerospace Corporation. He obtained a Ph.D. in aerospace engineering from Cornell University in 1984, was a post-doctoral associate at Cornell from 1984 to 1987, and joined the Aerospace Corporation in 1987 to pursue experimental research in advanced electric thrusters for spacecraft. He published over 20 papers on electric thruster research by 1995. Dr. Janson’s current research interests are nano/pico/femtosatellites, membrane spacecraft for orbital debris removal, spacecraft optical communications, microthrusters, formation flying, micro-electromechanical systems, and distributed space systems. He started investigating sub-kilogram mass spacecraft in 1989 and has published over 50 papers on small satellite propulsion requirements, basic design issues, MEMS for space applications, all-silicon satellites, and small satellite orbital architectures. Dr. Janson has flown MEMS experiments on sounding rockets, nanosatellites, CubeSats, the Space Shuttle, and the International Space Station. Dr. Janson chaired the SPIE “MEMS Components and Applications” conference in 2001, 2003, and 2004, and is co-editor of the book “Small Satellites: Past, Present and Future.” He is currently the principal investigator on the NASA-sponsored Optical Communications and Sensor Demonstration CubeSat program, and the NASA Innovative Advanced Concepts (NIAC) Phase II program, “Brane Craft.” He is a NASA NIAC fellow, a member of the IEEE, and currently holds 14 U.S. patents in orbital mechanics, spacecraft attitude sensors, glass/ceramic systems, thermoelectric coolers, and MEMS fabrication.

Dr. Janson

Biography: