Space Dust Impacts Detector Development for the Evaluation of Ejecta

AbstractThis paper aims at a) introducing the space dust impacts detector developed at Kyushu Institute of Technology (KIT), b) presenting the detector utility for the evaluation of ejecta, and c) raising awareness of the space community regarding the risk represented by orbital debris. The space dust impacts detector introduced into this paper belongs to the in-situ detection systems and has for purposes to be a) light, 30g, b) low cost, about EUR200, c) low power consuming, 0.01W, d) easily adaptable on-board of spacecraft, and e) able to detect impacts of debris with a diameter ranging from 100μm to 600μm. The detector is mounted on the nano-satellite, Horyu-II, developed at KIT and launched on May 18, 2012. The data received will be very helpful to identify the detector's strengths and weaknesses to improve it and create a second version that will aim at evaluating ejecta fragments produced during hypervelocity impact testing. An accurate evaluation of ejecta is critical for orbital debris risk assessment and mitigation. If all space activities were stopped, debris will still be created by chain reaction. The number of debris could then become so large, that the access to certain LEOs will be quasi-impossible, which will jeopardize the space exploration as well as scientific, educational, and security missions that benefit to all mankind. Debris is therefore a serious issue that should be taken into consideration at every step of the development of a small or large spacecraft

Using NASA Standard Breakup Model to Describe Low-Velocity Impacts on Spacecraft

The applicability is examined of the hypervelocity collision model included in the NASA standard breakup model 2000 revision to low-velocity collisions possible in space, especially in the geosynchronous regime. The analytic method used in the standard breakup model is applied to experimental data from low-velocity impact experiments previously performed at Kyushu University at a velocity range less than 300 m/s. The projectiles and target specimens used were stainless steel balls and aluminum honeycomb sandwich panels with face sheets of carbon fiber reinforced plastic, respectively. It is concluded that the hypervelocity collision model in the standard breakup model can be applied to low-velocity collisions with some simple modifications

Discharge on Solar Array Coupon By Debris Impact

Recently, a risk of impact between spacecraft and debris is increasing. An impact on solar arrays can cause electrical damage such as sustained arc as well as mechanical damage. If sustained arc occurs, electricity does not flow to the payload and the power generation capacity is reduced. In this study, discharge due to debris impact is reproduced by hypervelocity impact test, and plasma and discharge currents are measured. As a result, high density plasma and discharge due to impact were confirmed. Moreover, it became clear that some difference appears in the discharge current waveform depending on the impact point.14th Hypervelocity Impact Symposium 2017(HVIS2017), 24-28 April 2017, Canterbury, Kent, U

Development of Micro-Particles Accelerator with Pulse Formation

Space debris is one of major problems for recent space developments. When micro-debris of several hundred in diameter impacts spacecrafts, it may cause mission interruption. To design a safe and reliable space craft, we have to evaluate the risk of micro-debris impact by conducting ground-based hypervelocity impact experiments. To achieve these objectives, this study deals with the development of a plasma gun in which a plasma is created by applying high current and then accelerated by its own diffusion and Lorentz force. We think that it is important for accelerating projectiles to a higher velocity to shorten the current rise time and with a high plasma density. Therefore, to increase the velocity of the projectile, we examined the influence of the rise time and the plasma density. We conducted the experiments by a plasma gun and a WCR (Weak Current Removal) circuit to shorten the rise time and a short plasma gun to obtain a high-density plasma. These experimental results showed that it is necessary for accelerating to increase the maximum electric current, to adjust shooting the plasma to the peak time of the current and to increase the density of plasma.13th Hypervelocity Impact Symposium (HVIS 2015), April 27-30, 2015, Boulder, Colorad

Study of the Effects of Projectile Shape in the Asteroid Orbit Change by Spacecraft Impact

NEO (Near Earth Object) are the celestial bodies which pass near the Earth. One NEO deflection method is spacecraft impact. In order to estimate its results, it is necessary to clarify mechanism of momentum change of NEO. Generally, β is used as an evaluation index in this field and affected by various factors, so this study focuses on spacecraft shape. Five types of projectile shape were tested and compared in term of two aspects. In addition, we made comparison by using scaling law in order to compare the shape effect in the speed region which is assumed to using actual NEO deflection.14th Hypervelocity Impact Symposium 2017(HVIS2017), 24-28 April 2017, Canterbury, Kent, U

Development of Equipment to Estimate Momentum Shift in NEO Orbit Change by a Spacecraft Impact

For assessing the NEO orbit change by spacecraft impact, it is necessary to clarify the momentum shift at the impact time. Momentum shift is various amounts depending on the material of projectile and target, their shapes, and impact velocity. Currently, we have to collect more impact data by performing a simulated impact test on the earth because we do not have enough data to discuss design of a spacecraft impacter. Generally speaking, momentum shift is described at β (= about 1 ∼ 10 in other institution\u27s impact tests). We aim to get more efficient momentum shift by creating experimental conditions in which β is larger than 10. In this study, we developed a test equipment of pendulum type for measuring β, and performed impact tests after calibration of the pendulum equipment.2015 Hypervelocity Impact Symposium (HVIS 2015), April 27-30, 2015, Boulder, Colorad

Space Dust Impacts Detector Development for the Evaluation of Ejecta

This paper aims at a) introducing the space dust impacts detector developed at Kyushu Institute of Technology (KIT), b) presenting the detector utility for the evaluation of ejecta, and c) raising awareness of the space community regarding the risk represented by orbital debris. The space dust impacts detector introduced into this paper belongs to the in-situ detection systems and has for purposes to be a) light, 30 g, b) low cost, about EUR200, c) low power consuming, 0.01W, d) easily adaptable on-board of spacecraft, and e) able to detect impacts of debris with a diameter ranging from 100 μm to 600 μm. The detector is mounted on the nano-satellite, Horyu-II, developed at KIT and launched on May 18, 2012. The data received will be very helpful to identify the detector\u27s strengths and weaknesses to improve it and create a second version that will aim at evaluating ejecta fragments produced during hypervelocity impact testing. An accurate evaluation of ejecta is critical for orbital debris risk assessment and mitigation. If all space activities were stopped, debris will still be created by chain reaction. The number of debris could then become so large, that the access to certain LEOs will be quasi-impossible, which will jeopardize the space exploration as well as scientific, educational, and security missions that benefit to all mankind. Debris is therefore a serious issue that should be taken into consideration at every step of the development of a small or large spacecraft.2012 Hypervelocity Impact Symposium (HVIS 2012), September 16-20, 2012, Baltimore, Marylan

Ejecta From LPSO-Type Magnesium Alloy Targets in Hypervelocity Impact Experiments

Because long period stacking ordered (LPSO) type magnesium alloys have the low density, excellent mechanical strength and ignition resistance, LPSO-type magnesium alloys have a great potential as structural materials of satellites. Ejecta size and crater shape were examined when spherical projectiles struck targets made of LPSO-type magnesium alloy at hypervelocities of 2 km/s and 5 km/s. After impact experiments, crater surfaces and lips near craters were observed X-ray computed cosmography (CT) in detail. Ejecta collected from test chamber were measured. Results of LPSO-type magnesium alloy targets were compared with those of aluminum alloy (A6061-T6). Fracture behavior of LPSO-type magnesium alloy targets seemed to be brittle and many small ejecta from LPSO-type magnesium alloy were observed.14th Hypervelocity Impact Symposium 2017(HVIS2017), 24-28 April 2017, Canterbury, Kent, U

Revision Plan of ISO11227 Considering Oblique Impact Tests

The number of space debris is continuously increasing, and the risk of collision with a spacecraft is also increasing Secondary debris called ejecta is specifically threat to spacecraft, so an international standardization of the test procedure to evaluate ejecta, was developed and published as ISO11227 on September 15, 2012. This paper intends to show the necessity of oblique impact test by comparing spacecraft material oblique impact with normal impact and to consider the experimental condition of oblique impact test to revise this standard.2015 Hypervelocity Impact Symposium (HVIS 2015), April 26-30, 2015, Boulder, Colorad

Feasibility of Standardized Ejecta Evaluation for Spacecraft Surface Materials

Although a large spacecraft such as the International Space Station and other artificial satellites are thriving in the space environment due to the remarkable progress in the space development sector, their collisions with space debris are a growing concern. To examine the impact proof performance of spacecraft to space debris, hypervelocity impact experiments using a two-stage light gas gun and so on are necessary. However, space debris impact experiments are conducted in different manners dependent on the countries and the facilities. Therefore direct comparisons of the experimental results among different facilities are often difficult from the same viewpoint. In this study, the authors aim at assessment of international standardization of the hypervelocity impact experiments procedure. Projectiles with a diameter of 1 mm were used to simulate space debris impacting a target at 5 km/s. Copper witness plates were used to catch the secondary debris, namely ejecta, generated during the experiments. The size distributions of diameter of craters made by ejecta were measured on the witness plates, and they are compared one another among a solar array coupon, CFRP honeycomb and Aluminum honeycomb.2012 Hypervelocity Impact Symposium (HVIS 2012), September 16-20, 2012, Baltimore, Marylan