Site: National Space Development Agency of Japan (NASDA)
World Trade Center Bldg.
2-4-1, Hamamatsu-cho
Minato-km, Tokyo 105, Japan
http://www.nasda.go.jp

Date Visited: June 2, 1997

WTEC: K. Bhasin (report author), C. Bostian, W. Brandon, R. DePaula, C. Mahle, A. Mac Rae

Hosts:

BACKGROUND

NASDA provides overall leadership in Japan's effort to develop new space technology. NASDA, in cooperation with CRL and the Japanese aerospace industry, designs new spacecraft, develops new technology, implements experimental missions, and conducts tests and evaluations of flight prototypes. Overall, this effort is well coordinated among the several governmental agencies and private corporations involved.

NASDA has impressive test and integration facilities of world class quality (e.g., 13 m diameter thermal vacuum space chamber, 1,600 m3 acoustical test facility). Tsukuba Space Center has a relatively small staff of 250 NASDA professional employees, plus 100 to 180 contractor personnel. Projects at the center include the H-I and H-II launch vehicles (now completed) and the J-I launcher. Experimental satellite projects include the ETS-VI and -VII spacecraft, COMETS, JERS and the Japanese Experiment Module (JEM) for the International Space Station, the ADEOS Observation Program, and the HOPE reusable space shuttle that will be mated with the H-II launcher. Much of the design, manufacturing, test and integration of experimental communications satellites is left to the contractor and subcontractor organizations, typically NEC, MELCO and Toshiba.

RESEARCH AND DEVELOPMENT ACTIVITIES

NASDA's senior engineers briefed the WTEC team on the following three areas:

  1. Optical Intersatellite Link Technologies. Advances in optical intersatellite link technologies are being demonstrated by laser intersatellite link experiment OICETS, which is done in collaboration with ESA. The satellite is 3-axis stabilized and has a mass of 570 kg. The optical equipment (LUCE) is made by NEC with a mass of 140 kg. Overall size is 9.4 x 1.8 x 3.1 m. Launch is set for August 2000 on a J-1 rocket from Tanegashima. The planned orbit is 610 km at 35 inclination, with a 1 year lifetime. The optical intersatellite links will communicate with ARTEMIS (an ESA satellite in GEO orbit). Forward link 2.048 Mbps, beacon frequency 819 nm (ARTEMIS to OICETS); return link is 49.372 Mbps, 847nm, OICETS to ARTEMIS. Also, there is an S-band link to ARTEMIS and the ESA ground station in Redu (Belgium), NASDA's data relay tracking satellite (DRTS), and the ground station in Japan. Testing planned includes: optical device performance, acquisition, tracking, and pointing experiments (tracking better than 1 microrad, and pointing better than 2 microrad), communications experiment with BER <10e-6 to look at vibration in the satellite, and an optical link to the ground station at CRL. Matra equipment in the satellite measures vibration. The telescope is made of ceramic for thermal stability: 26 cm dia., with Canon reflective optics.

    Preliminary design was completed in 1994; the critical design phase will be completed in 1998. LUCE-EM will also be completed in 1998. Going forward, the schedule calls for system integration in 1998-99, then storage for several months because of the ARTEMIS launch delay. The test program has been planned and agreed with ESA.

    Other work in this area at Tsukuba includes the following:

  2. Advance Antenna Technology. Modular large, deployable antenna for ETS-VIII and follow-on satellites. ETS-VIII will have 2 large (10-15 m) antennas at S-band for mobile communications experiments (telephone handsets), fed by a 32 element phased array feed generating 4 to 5 spot beams. The target is >15 m, <170 kg (per reflector), <2.4 mm rms deviation over temperature range. Individual modules are about 4 m dia.; 19 modules make a 15 m reflector, 7 modules make a 10 m reflector. Surface is a gold braided mesh shaped by cables, with a hexagonal truss structure (truncated pyramid) as backing. NASDA is responsible for large reflectors, antenna integration and satellite development. Toshiba makes the reflector, Mitsubishi the bus. CRL, ASC (Advanced Satellite Communications Lab) and NTT are sponsors. Vibration distortion in orbit is considered small. The phased array generated beams can be repointed in orbit. Launch is planned in 2002. Onboard processor packet mode is being worked on by CRL, TDMA by ASC.
  3. Launcher Research and Development Program - H-II is the fourth generation rocket derived from N-1 (based on U.S. Delta technology). The 2-stage design, powered by liquid H2 and O2, can lift about 2,000 kg to GEO. It has flown 4 times successfully (it is the only rocket in the last 20 years not to have a failure). F5 and F6 were scheduled for launch in 1997 (COMETS and JETS-VII/TRMM) then there will be no more launches until 1999. An improvement program is in place for F7 and F8 in 1999; F9 will be the first H-IIA with about 3,000 kg lift to GEO (launch in 2001). The H-IIA has a large liquid rocket booster (actually another first stage) attached to the side, in addition to two solid strap-ons. NASDA is working on gradual improvements and cost reduction; the second stage will be redesigned for H-IIA. A further model is in planning with 2 LRBs and about 4,000 kg lift to GEO (no launch date yet). The LRB is currently not reusable but NASDA is planning experiments to see if it could eventually be reusable.

The launch complex will be upgraded so that 2 H-IIAs can be processed in parallel in the vertical assembly building. Now only one at a time can be processed and the satellite is mounted at the launch pad. NASDA is striving for a 20 day launch cycle.

CONCLUSIONS

Even though there is reduction in its total space program, NASDA appears still well funded in satellite communication programs. The H-II rocket is pointed towards commercial launch capability. The satellite communication program is well coordinated with the government agencies and the research centers. Considerable emphasis is placed on advanced communication experiments for satellite payload development.


Published: December 1998; WTEC Hyper-Librarian