Prof. Junichiro Kawaguchi has been engaged in the Astrodynamics and its applications to the real missions for decades.

[A] Interplanetary Flight Study
He built the fundamental researches started later 1970s and early in 1980s. They seem old subjects. But it is never true. For instance, the use of tidal force in space exploration is a hot topic even now and in future. The researchers can still find new analyses and applications.
These were applied to real missions of ISAS (Institute of Space and Astronautical Science)/JAXA (Japan Aerospace Exploration Agency). They are

(1) Hiten (MUSES-A) mission: Using Double Lunar Swing-bys and was captured by the Moon using Tidal Force Effect (via so-called Weak Stability Boundary)
(2) GEOTAIL mission in International ISTP program.
(3) Nozomi (PLANET-B) mission: Double Lunar Swing-bys was adopted and accelerated by Tidal Force Acceleration to the Mars.

The subjects of the themes are:
1 Man-Machine / GUI I/Fed, Computer Aided Orbital Synthesis (Later in 1980s to 1990s)
2 Double Lunar Swing-by Trajectory (Later in 1980s to 1990s)
3 Lunar and Tidal Force to Orbital Transfer (Early to Middle of 1990s, 2000s to 2010s)

The contents are represented by, but not the most suitable one:
“On making use of lunar and solar gravity assists in LUNAR-A, PLANET-B missions,”
Junichiro Kawaguchi, Hiroshi Yamakawa, Tono Uesugi, Hiroki Matsuo,
Acta Astronautica, Volume 35, Issues 9–11, May–June 1995, Pages 633-642
https://doi.org/10.1016/0094-5765(95)00013-P

[B] Sample & Return Flight Sequence and Associated Astrodynamics Techniques
Through the practices and experiences distilled, he launched the world's first sample and return mission from small objects outside Earth gravity sphere. It is Hayabusa (MUSES-C) mission.
The new techniques were developed and devised through the completion of the mission. New exploration era should be based on the researches and studies here. They may be good themes for the next generation researchers.

The techniques and engineering researches were developed for or devised during the real missions.
Applied to Real Missions of ISAS/JAXA
• Hayabusa (MUSES-C) to NEA Itokawa
• Hayabusa-2 to NEA Ryugu

The subjects of the themes are:
4 Low Thrust Orbit Optimization Scheme (Early 1990s to Early 2000s)
5 Optical / Radio Hybrid Guidance and Navigation (Later in 1990s)
6 EDVEGA (Electric Delta-V Earth Gravity Assist) Technique (Early 2000s)
7 Automated Sun Tracking via Solar Radiation Pressure (Middle of 2000s)
8 Rp-Tp Reentry & Landing Guidance Scheme (Later 2000s)

4., 6. Low Thrust Optimization and EDVEGA were presented many places.
An example, but not a representative one, is found in:
“Performance Evaluation for the Electric Delta-V Earth Gravity Assist (EDVEGA) Scheme,”
Jun'ichiro Kawaguchi,
AIAA/AAS Astrodynamics Specialist Conference and Exhibit
05 August 2002 - 08 August 2002, Monterey, California,
https://doi.org/10.2514/6.2002-4899

5. Proximity Descent and Touch Down Techniques were presented many places.
An example, but not a representative one, is found in:
“Hayabusa-final autonomous descent and landing based on target marker tracking,”
T. Yoshimitsu, J. Kawaguchi, T. Hashimoto,
September 2009 Acta Astronautica 65(5-6):657-665
https://doi.org/10.1016/j.actaastro.2009.01.074
https://www.researchgate.net/publication/222191862_Hayabusa-final_autono...

7. Survival Cruise in Hayabusa utilized Special Attitude Control Scheme:
An example, but not a representative one, is found in:
“A fuel-free Sun-tracking attitude control strategy and the flight results in Hayabusa
(MUSES-C),”Kawaguchi, J., Shirakawa, K.,
Advances in the Astronautical Sciences
Volume 127 PART 2, 2007, Pages 1989-1995
17th Annual Space Flight Mechanics Meeting; Sedona, AZ; United States; Code 73989

8. Reentry Operation, Guidance Strategies were presented many places.
A few examples, but not a representative one, are found in:
“Return of Hayabusa spacecraft and reentry of its capsule,”
Kawaguchi, J., Kuninaka, H., Yoshikawa, M.,
Advances in the Astronautical Sciences
Volume 141, 2011, Pages 403-414
34th Annual AAS Rocky Mountain Section Guidance and Control Conference; Breckenridge, CO;
United States; 4 February 2011 through 9 February 2011; Code 97452
“Trajectory Correction Maneuver of Hayabusa in Earth Reentry Phase,”
Masatoshi Matsuoka, Jun'ichiro Kawaguchi, Makoto Yoshikawa, Takafumi Ohnishi,
http://www.hayabusa.isas.jaxa.jp/kawalab/astro/pdf/2010B_2.pdf

[C] He has been attempting to devise innovative astrodynamics schemes even now and for future.
While he was a Professor at the University of Tokyo, he mentored the following themes to the PhD candidate students and some themes are still studied by those students. However, those and other themes can be mentored at ANU as well. While some themes may not belong purely to the Astrodynamics, he thinks the themes can be more liberal than sharpened.

9 Formation Flight / Constellation - Guidance & Stabilization
(1990s and 2000s, Later 2010s to present)

10 Guidance only via Spin Control in Spinning Solar Sails (Middle of 2000s, present)
Subject: Bilinear Systems and Exact Linearization

11 Internal Structure Estimation of Small Bodies from difference between Geoid and Shape
(Later 2000s)

12 Oscillation Behavior and Terrain Formation in Rubble Pile Objects (Early 2000s)

13 Trajectory Control via Membrane Shape Control by Boundary Excitation in Spinning Solar Sails
(Middle of 2010s)

14 Autonomous, Distributed and Independent Control System (Early 2010s to present)

15 Non-holonomic Simultaneous Attitude and Shape Control in Space Robots
(Later 2010s to present)

16 Optical Pose and Dynamic Property Estimation (Later 2010s to present)

17 Wireless On-Orbit Interfelometry Observation Method (Later 2010s to present)

18 Asynchronous One-Way Ranging and Clock Synchronization (present)

19 Mission Analysis and Trajectory Synthesis with Optimization (present)

9. About the Formation Flight / Constellation - Guidance & Stabilization:
An example, but not the most suitable one, is at:
“Formation configuration as a function of degree of knowledge sharing.”
Saiki, T., & Kawaguchi, J. (2003).
213-221. 54th International Astronautical Congress of the International Astronautical
Federation (IAF), the International Academy of Astronautics and the International Institute of
Space Law, Bremen, Germany.
Also, in:
“Formation Flying Transition Behavior to Localized and Layered Control Laws,”
Kawaguchi J. (JAXA/ISAS), Saiki T. (Univ. Tokyo);
18th International Symposium on Space Flight Dynamics
Munich, Germany, 11 - 15 October, 2004
A paper following the paper above is in:
http://www.hayabusa.isas.jaxa.jp/kawalab/astro/pdf/2004C_15.pdf

10. As to the Guidance only via Spin Control in Spinning Solar Sails, this is, at the same time, the subject: Bilinear Systems and relates to the Exact Linearization subject.
An example is found in:
“Attitude Control of a Spinning Solar Sail via Spin Rate Control using Exact Linearization,”
Go ONO, Yuya MIMASU and Jun'ichiro KAWAGUCHI,
Trans. JSASS Aerospace Tech. Japan
Vol. 12, No. ists29, pp. Pd_27-Pd_32, 2014

11. As for the Internal Structure Estimation of Small Bodies from difference between Geoid and Shape, this is also related to the planetary science.
An example is accessed by:
“Study on the Gravity Field on the Surface of Itokawa,”
Motooka, N. and Kawaguchi, J.
Proceedings of the 22nd Workshop on JAXA Astrodynamics and Flight Mechanics, ISAS/JAXA,
Sagamihara, 2012, A-15,
http://www.hayabusa.isas.jaxa.jp/kawalab/astro/pdf/2012A_15.pdf
And a paper following the article above is found in:
“Estimation of Interior Density Distribution for Small Bodies: The Case of Asteroid Itokawa,”
Masanori KANAMARU and Sho SASAKI,
Trans. JSASS Aerospace Tech. Japan
Vol. 17, No. 3, pp. 270-275, 2019
https://doi.org/10.2322/tastj.17.270

12. On the Oscillation Behavior and Terrain Formation in Rubble Pile Objects, this is also somewhat related to the planetary science aspect.
An example is reached at:
“Categorization of Brazil nut effect and its reverse under less-convective conditions for
microgravity geology,”
Toshihiro Chujo, Osamu Mori, Junichiro Kawaguchi, Hajime Yano
Monthly Notices of the Royal Astronomical Society, Volume 474, Issue 4, March 2018, Pages 4447– 4459, https://doi.org/10.1093/mnras/stx3092

13. About the Trajectory Control via Membrane Shape Control by Boundary Excitation in Spinning Solar Sails, this subject belongs to the distributed petameter system governed by the partial derivative equations (PDE). This is conceived one of the real applications in controlling PDE systems
An example is found in:
“Interplanetary Mission Design for Spinning Solar Sails Utilizing Active Shape Control of Sail
Membranes,”
Yuki Takao, Osamu Mori and Junichiro Kawaguchi
Published Online:7 Jan 2018, https://doi.org/10.2514/6.2018-0212

14. About the Autonomous, Distributed and Independent Control System, this is currently a patented technology and published open. The essence derived from the power control system onboard the spacecraft. Conventional control system relies on the measurements. But this does not. No measurement. Appropriate for the energy management as well. There is MIMO application to be studied more.
It is explained at:
“Power control system and method, and information communication ability control system and
method,”
Junichiro Kawaguchi, United States Patent 10,050,799 August 14, 2018
https://patft.uspto.gov/netacgi/nph-Parser?
Sect1=PTO2&Sect2=HITOFF&p=1&u=%2Fnetahtml%2FPTO%2Fsearch-bool.html&r=2&f=G&l=50&co1=AND&d=PTXT&s1=kawaguchi.INNM.&s2=patched.AANM.&OS=IN/kawaguchi+AND+AANM/patched&RS=IN/kawaguchi+AND+AANM/patched

15. About the Non-holonomic Simultaneous Attitude and Shape Control in Space Robots, he can mentor the researchers on both the analytical aspects and applications. This realizes what we call “Transformer Space Robots.”
An example is found in:
“Attitude control strategy of a transformable spacecraft for orbital station-keeping around
sun-earth L2,”
Kubo, Y., Chujo, T., Hernando-Ayuso, J., Kawaguchi, J.,
Proceedings of the International Astronautical Congress, IAC, Volume 2018-October, 2018,
69th International Astronautical Congress: #InvolvingEveryone, IAC 2018; Bremen; Germany; 1
October 2018 through 5 October 2018; Code 147415
https://iafastro.directory/iac/paper/id/46808/ext/appendix/IAC-18,C1,3,2...

16. Concerning the Optical Pose and Dynamic Property Estimation theme, he can mentor especially the estimation of the dynamical properties rather than simple pose estimation. So far, even the inertia tensor is estimated by the scheme.
An example is in:
http://www.patchedconics.com/ME.html
Preparatory work is also found in:
https://iafastro.directory/iac/paper/id/58450/ext/appendix/IAC-20,A6,5,1...

17. As for the Wireless On-Orbit Interfelometry Observation Method, this sounds the subject in Astronomy. However, contemporary formation applications fail to extract the solid merits, and he has proposed a new formation flight application. This is it.
A preparatory description is provided in:
“A Study on Estimation Methodology of Signal Intensity Distribution for Space VLBI,”
Masahiro Fujita, Yuichiro Nada, Yuki Takao, Ahmed Kiyoshi Sugihara, Junichiro Kawaguchi,
33rd ISTS, 2022-j-02,
https://drive.google.com/file/d/133vMlefuCTu4BzYOg8xTWbdS5pThbSPw/view?u...

18. About the Asynchronous One-Way Ranging and Clock Synchronization, he initiated the new inexpensive ranging scheme that is applicable for micro to nano spacecraft for the navigation purpose flying interplanetary field. This is the ongoing development issue at JAXA and a few Japanese universities. But he can include the activity at ANU as well.
A brief and preparatory description is in:
“Asynchronous One-Way Ranging Method Applied to Lunar and Interplanetary Probes,”
Junichiro Kawaguchi, Yuichiro Nada, Yuka Ishigooka, Toshinori Kuwahara, Kazuya Yoshida,
33rd ISTS, 2022-l-21,
https://drive.google.com/file/d/138-0zUBLSXVTChK1ln-R-_I0TMe8wpkN/view?u...

19. Regarding the Mission Analysis and Trajectory Synthesis with Optimization at large,
a variety of studies are running toward post-Hayabusa/Hauabusa-2 looking at the Moon and Mars exploration as well. He can mentor and inspire the researchers to the new concepts in future.
One of the examples is on the subject of E2I (Eccentricity to Inclination) conversion. This can be applied to a concise solar polar orbit. (Early in 2000s)
And a few certain examples may be found in:
“On Ballistic Acquisition of Short Period Out-Of-Ecliptic Trajectories,”
Jun'ichiro Kawaguchi, Yasuhiro Kawakatsu, Mutsuko Morimoto, Justin A. Atchison, AAS 09 - 339
“Short-period Ballistic Out-of-Ecliptic Trajectories via Multiple Venus & Earth Swing-bys and
VEGA-driven Multiple Earth Swing-bys,”
Kawaguchi, J., Kawakatsu, Y., Morimoto, M., et al.,
AAS/AIAA Astrodynamics Specialists Conference, 9-13
Aug. 2009, Pittsburg, PA, Proceedings of the 22ndInternational Symposium on Space Flight
Dynamics, 2011.
“ON ULTIMATELY THE MOST HIGHLY INCLINED, THE MOST CONSICE SOLAR POLAR TRAJECTORY WITH
PRACTICALLY THE SHORTEST PERIOD,”
Junichiro Kawaguchi,
6th ICATT, ESA, 14-17 March 2016, Darmstadt,
https://indico.esa.int/event/111/contributions/295/attachments/364/405/J...