Masafumi Iai

Tokyo Tech CubeSat: CUTE-I - Design & Development of Flight Model and Future Plan -

Laboratory for Space Systems, Tokyo Institute of Technology finished development of CUTE-I and is waiting for its launch on June 30, 2003. CUTE-I is the first CubeSat of Tokyo Institute of Technology, that is a 10 cm-edge cube-sized satellite of less than 1kg mass. CUTE-I has three missions such as communication, attitude sensing and deployment. to establish a bus component design for pico satellites like the CubeSat. In parallel with the CUTE-I development, we also developed a separation mechanism that is used to separate CUTE-I from the launcher on orbit. In this paper, we describe the design of CUTE-I and the separation mechanism as well as results of environment tests such as long-range communication test, thermal vacuum test, vibration test and separation test. We also mention a Tokyo Tech future plan on our satellite development.

Excavation of Lunar Regolith with Large Grains by Rippers for Improved Excavation Efficiency

AbstractAs human activities expand to the Moon, Mars, and other extraterrestrial bodies, it will be necessary to use local resources rather than bringing everything from Earth. In situ resource utilization (ISRU), or planetary surface engineering, starts with excavation and dirt-moving. The current study focuses on excavation of lunar regolith simulant by blading with and without preripping (mechanical raking) and points out the need for considering the relative proportion of coarse grains in regolith when dealing with excavation force and energy. The coarse-grain content of the lunar regolith, estimated from 11 Apollo cores, can reach 30% by mass. Prior ripping of vibrationally compacted beds of a standard fine regolith simulant can decrease total excavation resistance (when subsequent blading is included) by up to 20% for relative regolith densities greater than 60%. The effect of coarse grains on the response of compacted regolith to excavation was more significant than would be expected in most terres...

NEW SPINNING DEPLOYMENT METHOD OF LARGE THIN MEMBRANES WITH TETHER CONTROL

In this paper, we propose one membrane deployment method: tether-controlled spinning deployment. Very large, thin and flexible membrane (sail) is packed and then is deployed in orbit. In the process of membrane deployment, we use controlled tethers to stably deploy the membrane. Some types of the system are proposed, and the characteristics and technical issues are briefly mentioned. Numerical simulation results using a distributed mass-tether network model show the potential advantage of the proposed method. An experimental set-up of the proposed deployment using the two-dimensional micro-gravity simulators developed at Tokyo Institute of Technology is introduced, and the result of preliminary deployment experiments with a thin membrane of 1m-sized is shown.

Tokyo Tech 1kg Pico-Satellite CUTE-I-Development, Launch & Operations

Abstract Tokyo Institute of Technology, Laboratory for Space Systems had developed a 1 kg pico-satellite CubeSat, CUTE-I, and it was successfully launched on June 30 2003 by a Eurockots rocket. CUTE-I is one of the first launched CubeSats and also the smallest civilian satellites in the world, which are able to make dual-directional communications with the ground stations. In this paper, the total design of CUTE-I flight model and operation results focused on its attitude analyses are explained.

JetGun Sat “TOPPU”

In this paper, we report a conceptual design of micro-satellite for the verification of formation flying technologies. This satellite is a type of mothership-daughtership configuration called TOPPU which means a gust wind. The two satellites are connected by a tether; the mothership satellite has a docking mechanism installed, and a reel mechanism as well as gas jet gun to perform various orbital experiments. The system design of TOPPU is discussed, as is the progress of satellite system development.

Effect of Regolith Compaction on Ripping Efficiency

Lunar regolith is known to be surprisingly stiff compared to terrestrial soils because of its angular grain shape, very small grain size, and high relative density. One of the ways to reduce the excavation force and energy is to loosen the soil prior to excavation. In experiments using JSC-1A lunar regolith simulant at three different compaction levels, ripping of the simulant was followed by pushing a wide blade though it. The energy required to move the ripper and the wide blade was measured and analyzed to determine how the excavation energy is affected by the density of simulant, as well as the number and position of tines on the ripper. It was found that ripping increases the efficiency of excavation of lunar regolith denser than 60% relative density. The optimal spacing of tines in this simulant is about 25mm (1.0inch), which agrees with the condition that the failure zones formed by neighboring tines just touch each other.

Titech CanSat Project 2000: Report of Sub-orbital Flight and Balloon Experiment

We have participated in the ARLISS (A Rocket Launch International Student Satellite) project since 1999 to design, manufacture and operate small satellites on students’ initiative. These satellites called CanSat are the size of soft drink can (350ml). We launch CanSats from the Black Rock desert in Nevada to 12,000ft using an amateur rocket, and drop them with a parachute. In this paper, we describe the subsystem design, mission and some results of the experiments on each CanSat, and report the results of an additional experiment using a balloon.