H-IIA Flight 26 - Secondary Payloads
The H-IIA launch vehicle carrying the Hayabusa-2 Asteroid Exploration Spacecraft into a heliocentric orbit at a characteristic energy (C3) of 21km²/s² will also carry three secondary payloads into the same trajectory – offering a rare chance for small spacecraft and university satellites to fly beyond Low Earth Orbit. Part of the secondary payloads of H-IIA F26 are the PROCYON microsatellite that will demonstrate a microsatellite bus for deep space exploration and asteroid flybys, the Shin’en-2 nanosatellite to demonstrate long range communication technologies and the DESPATCH/ArtSat-2 joint satellite project to send artwork into deep space.
>>>Detailed Hayabusa Overview
>>>Detailed Hayabusa Overview
The panels deliver power to all satellite systems, distributed by a dedicated system that conditions that satellite’s 28-Volt unregulated power bus and controls the state of charge of the onboard battery. The majority of power will be used by the ion propulsion system.
The High Gain Antenna is a flat patch antenna installed on the +z panel of the spacecraft and has a small operational boresight while the MGA that resides on a side panel has a large cone and the LGAs deliver omni-directional communications. The X-Band system operates at a frequency of 7.1 GHz for command uplink and 8.4 GHz for telemetry and data downlink that reaches a data rate of 32kbit/s using the High–Gain Antenna and drops to 8bit/s on the Low Gain Antennas. Uplink data rates can be selected between 15.6, 125 and 1,000 bit/s. The communication system should be operational up to a range of 2 Astronomical Units. On the ground, Japan's 64-meter Deep Space Antenna and a smaller 34-meter antenna in Japan will be used to communicate with Procyon with support from 70-meter Deep Space Network stations during critical mission phases such as flybys.
The Ion Thruster Unit consists of an ion source, a neutralizer, a thruster valve, a gas distributor, gas isolator, DC blocks, and ion accelerator. Like its bigger sister Hayabusa, PROCYON uses a electron cyclotron resonance ECR microwave discharge – a new design that eliminated solid electrodes and associated heaters that were used as part of previous systems.
The PROCYON satellite is equipped with an optical telescope that will be used as an optical navigation sensor during proximity operations near the target asteroids to provide data for attitude maneuvers needed to keep the asteroid within its field of view to also capture scientific imagery of the asteroid’s surface. The telescope uses a rotating scanning mirror receiving light from a 5 centimeter aperture. The telescope has a focal length of 15 centimeters.
PROCYON launches with no specific asteroid target. A number of potential flight trajectories have been identified, but the selection of a final target will depend on the vehicle’s actual insertion trajectory since the propulsive capabilities of the spacecraft are limited. A precise trajectory fix will be obtained through Delta-Differential One-Way Ranging supported by the X-Band payload.
After a target is selected, PROCYON will either follow a direct flight to the asteroid in a transfer lasting up to two years or choose an Earth flyby profile. In this scenario, the spacecraft would use its ion thrusters for half a year in its heliocentric orbit for a total delta-v up to 100m/s and a Xenon consumption of 0.6kg to set up a flyby trajectory that delivers the vehicle to its target asteroid within one year. After the close asteroid flyby at a distance of around 50km and a relative velocity up to 10km/s, targets for a possible extended mission will be identified based on propellant availability.
Shin'en-2 is a small satellite payload carrying an amateur radio payload into deep space. The satellite was developed at Kagoshima University and has a mass of just 17 Kilograms, being 49 by 49 by 47.5 centimeters in size. The satellite uses a lightweight thermoplastic Carbon-fiber-reinforced polymer structure to make up its external and internal structural components forming a polyhedron with its outer panels that are covered with solar cells for power generation. The structural system has a mass of just 2.85kg.
The satellite carries a radio payload operating in the amateur UHF and VHF bands. The satellite uses three downlink channels at 435.270, 437.505 and 437.385 MHz for the downlink of basic telemetry parameters, data from a NASA radiation dosimeter and messages that can be uplinked from radio amateurs across the world.
Telemetry parameters included in the downlink are battery voltages, current levels, spacecraft temperatures and a series of other parameters. Uplink to the satellite is possible on two channels in the 145 MHz VHF band, messages to the satellite are accepted at a frequency of 145.942 MHz using frames with a length of 13 bytes including 6 bytes containing data.
The radiation dosimeter installed on the satellite was developed at NASA’s Johnson Space Center, Prairie View A&M University and the The University of Nevada for the study of Galactic Cosmic Rays and Solar Energetic Particle events.
ArtSat-2 (Art Satellite-2)/DESPATCH (Deep Space Amateur Troubadour's Challenge) is a joint project of Tama Art University and Tokyo University sending a 3D printed sculpture into space along with an amateur radio payload.
The sculpture measures 50 by 50 by 45 centimeters in size and has a mass of about 30 Kilograms. The radio operates at the amateur UHF frequency of 437MHz, transmitting ‘poetic messages’ from space using its own telemetry parameters such as voltage and temperature in a 'tele-creation' process. Only batteries are used by the satellite that will remain powered for approximately seven days when the distance between Earth and the spacecraft will be approximately 3 million Kilometers.