Mission: Hayabusa 2 Options

[spdf]

JAXA wants to continue with Hayabusa 2. However there is/was a huge fight about the budget. Main problem was the budget for the launch vehicle. 2 months ago or so there was a report which said, that JAXA had to find another launch vehicle or the project gets cancelled. Now the Italian space agency played saviour and overed the VEGA. So finally we might see another Hayabusa in 2011.


It was mentioned here:
http://www.jspec.jaxa.jp/080110Final_IPEWG-ProgramBook.pdf

[Paolo]

a rather detailed description of PROCYON (in Japanese) is available here

[pandaneko]

a rather detailed description of PROCYON (in Japanese) is available here

More pages (18,19,20,22) to follow. P

(No need to translate pages 16 and 17)

System configuration

Hodoyoshi satellite system is used for the main system components of power and EDHS/EAOCS.
(Tuning and improvements for deep space mission will be conducted for PROCYON)

①Comms. system (ISAS)
②Propulsion system (Univ. Tokyo and ISAS)
③ Mission system (Univ. Tokyo, Meisei Univ, Rikkyo Univ)
(optical camera for asteroid observation)
(geo-corona imager)

P-18
Ultra smal comms. system for deep space probes
We are developping ultra small X-band comms. system which is compatible with other deep space probes such as Hayabusa

Specs. of PROCYON communication system
目仕様
Frequency band is X, category B
Uplink frequency: 7.1 [GHz]
Downlink frequency: 8.4 [GHz]
Coherent ratio: 749/880
Output power: larger than 15W
Command bit rate: 15.625, 125 [bps], 1 [kbps]
Telemetry bit rate: 8 [bps] 〜4 [kbps]
Maximum communicable distance: larger than 2 [AU]
Orbit determination: R&RR
Grund stations: Usuda and Uchinoura
P-19
HGA(PZ plane)
MGA(MZ plane)
LGA(PZ,MZ plane)

Unified propulsion system of ion thruster and cold gas jets
(what follows is the character strings inside top square)
Unified propulsion system using Xe based electrical propulsion (small acceleration and high specific impulse) and cold gas jet system for attitude control (RW unloading)+ orbit conrol (acceleration)

(middle table contents as follows)
Probe total mass: 60 kg
Xe mass: 2.5 kg
MIPS specific impulse: 1200s
MIPS propulsion: 300×10-6N
CGJ specific impulse: 25s
CGJ propulsion: 11×10-3N

(below satellite picture, colours correspond)
Ion thruster thrust direction
CGJ is used together with RCS for orbit control

(character string at very bottom)
Ion thruster for Hodoyoshi satellite

P-20

(No need to translate page 21)

Mission System

（Optical navigation and flyby camera）

• Imaging system for high speed/ultra close flyby

• Realise angular resolution even by the small satellite borne telescope required for optical navigation during close flyby of asteroid

• Realise high speed changes in line of sight by controling the rotation of part of the telescope system (driving mechanism) through image feedback

Optical system
High speed line of sight changes by driving mirorr rotation
→capable of tracking asteroid before and after closest approach
(inside top right square)
Optical system capable of observing objects as dim as magnitude 12 despite 50mm aperture and 150mm focal length
(inside bottom right square)
Driving mechanism capable of controling the rotational angle around optical axis of the telescope
P-22

(end of pages 18, 19, 20, and 22)