Engineering topics

Giovane, Frank

Publications and source records attributed to Giovane, Frank.

3 records

NASA NTRS2012

DRAGONS - A Micrometeoroid and Orbital Debris Impact Sensor

The Debris Resistive/Acoustic Grid Orbital Navy Sensor (DRAGONS) is intended to be a large area impact sensor for in-situ measurements of micrometeoroids and orbital debris (MMOD) in the approx.0.2 to 1 mm size regime. These MMOD particles are too small to be detected by groundbased radars and optical telescopes, but still large enough to be a safety concern for human space activities and robotic missions in the low Earth orbit (LEO) region. The nominal detection area of DRAGONS is 1 sq m, consisting of four 0.5 m x 0.5 m independently operated panels. The concept of the DRAGONS design is to combine three different detection technologies to maximize information extracted from each detected impact. The first technology is a resistive grid consisting of 62.5-microns-wide resistive lines, coated in parallel and separated by 62.5 micron gaps on a Kapton film. When a particle a few hundred micrometers or larger strikes the grid, it world penetrate the film and sever some resistive lines. The size of the damage area can be estimated from the increased resistance. The second technology employs a dual-layer, 25-microns-thick Kapton film with a 10 cm separation. By measuring the time difference between impacts on the two films, the impact speed can be calculated. The third technology is based on polyvinylidene fluoride (PVDF) acoustic impact sensors. Multiple PVDF sensors are attached to the backside of both Kapton films to provide impact timing measurements. The impact location on each film can be identified from the triangulation of signals received at different PVDF sensors and provides an estimate of the impact direction. The development of DRAGONS is supported by the NASA Orbital Debris Program Office. The project is led by the U.S. Naval Academy (USNA), with additional collaboration from the U.S. Naval Research Laboratory (NRL), the University of Kent at Canterbury in Great Britain, and Virginia Tech (VT). The short-term goal of DRAGONS is to advance its Technology Readiness Level to 9 and to demonstrate the system capabilities of detecting and characterizing submillimeter MMOD impacts. The long-term goal is to deploy a large detection area (>1 sq m) DRAGONS to 700-1000 km altitude and collect sufficient data for better environment definition of MMOD in the 0.2- to 1-mm size regime. The Preliminary Design Review (PRD) of DRAGONS was held at the USNA in June 2012. The Critical Design Review (CDR) is scheduled for early 2013. A flight-ready unit with a 0.25 sq m detection area will be completed and tested by the end of September 2013. The biggest challenge for the project, however, is to identify a demonstration opportunity on the International Space Station in the coming years.

Liou, J. C.↗

NASA NTRS2009

Handbook for Designing MMOD Protection

Spacecraft are subject to micro-meteoroid and orbital debris (MMOD) impact damage which have the potential to degrade performance, shorten the mission, or result in catastrophic loss of the vehicle. Specific MMOD protection requirements are established by NASA for each spacecraft early in the program/project life, to ensure the spacecraft meets desired safety and mission success goals. Both the design and operations influences spacecraft survivability in the MMOD environment, and NASA considers both in meeting MMOD protection requirements. The purpose of this handbook is to provide spacecraft designers and operations personnel with knowledge gained by NASA in implementing effective MMOD protection for the International Space Station, Space Shuttle, and various science spacecraft. It has been drawn from a number of previous publications [10-14], as well as new work. This handbook documents design and operational methods to reduce MMOD risk. In addition, this handbook describes tools and equations needed to design proper MMOD protection. It is a living report, in that it will be updated and re-released periodically in future with additional information. Providing effective and efficient MMOD protection is essential for ensuring safe and successful operations of spacecraft and satellites. A variety of shields protect crew modules, external pressurized vessels and critical equipment from MMOD on the International Space Station (ISS). Certain Space Shuttle Orbiter vehicle systems are hardened from MMOD impact, and operational rules are established to reduce the risk from MMOD (i.e., flight attitudes are selected and late inspection of sensitive thermal protection surfaces are conducted to reduce MMOD impacts). Science spacecraft include specific provisions to meet MMOD protection requirements in their design (for example, Stardust & GLAST). Commercial satellites such as Iridium and Bigelow Aerospace Genesis spacecraft incorporate MMOD protection. The development of low-weight, effective MMOD protection has enabled these spacecraft missions to be performed successfully. This handbook describes these shielding techniques. For future exploration activities to the Moon and Mars, implementing high-performance MMOD shielding will be necessary to meet protection requirements with minimum mass penalty. A current area of technology development in MMOD shielding is the incorporation of sensors to detect and locate MMOD impact damage. Depending on the type of sensor the signals from the sensor can be processed to infer the location of the impact and the extent of damage. The objective of the sensors is to locate critical damage that would endanger the spacecraft or crew immediately or during reentry (such as an air leak from crew module or critical damage to thermal protection system of reentry vehicles). The information from the sensors can then be used with repair kits, patch kits, hatch closure or other appropriate remedial techniques to reduce MMOD risk.

Arnold, Jim↗

NASA NTRS1996

The concept of a facility for cosmic dust research on the International Space Station

A proposal for the development of a permanently operating facility for the experimental investigation of cosmic dust-related phenomena onboard the International Space Station (ISS) is presented. Potential applications for this facility are the convection-free nucleation of dust grains, studies of coagulation and aggregation phenomena in a microgravity environment, investigations of heat transport through, and dust emissions from, high-porosity cometary analogs, and experiments on the interaction of very fluffy dust grains with electromagnetic radiation and with low pressure gas flows. Possible extensions of such a facility are towards aerosol science and colloidal plasma research.

Blum, Juergen↗