From leading a 330-strong coalition team across multiple operations, to briefing the former United States Vice-President Kamala Harris on space support, Group Captain Julien Greening's posting to US Space Command has been recognised with one of the most prestigious US military honours, the Legion of Merit.
Group Captain Greening is currently the Director of the Space Control Directorate within Joint Capabilities Group.
From January 2022 to December 2024 he served as the first Australian Deputy Director of the US Combined Space Operations Center (CSpOC) at Vandenberg Space Force Base, California.
He led the US operational level command and control centre (the equivalent of an air operations centre for the space domain) across multiple operations, synchronising effects between US combatant commands, five operational centres and 75 tactical units, in concert with commercial and allied partners from Canada, the United Kingdom, France, Germany, and Australia.
The CSpOC's mission is to execute command and control of space forces to achieve theatre and global objectives.
Group Captain Greening's leadership contributed to the success of major allied space missions.
This was achieved through directing forces across the space enterprise, to generate effects and provide services including, satellite communications, space domain awareness, space control, missile warning, intelligence, environmental monitoring and position, navigation and timing.
In recognition of this achievement, Group Captain Greening was presented the Legion of Merit by the Head of Space and Cyber Capabilities, Rear Admiral Andrew Quinn, and the US Air and Space Attaché, Lieutenant Colonel Brittany Morreale.
For Group Captain Greening, the honour reflected a collective achievement.
"It's really a tribute to the men and women of the CSpOC, who worked together to deliver space effects day after day," he said.
'Understand that delivering space capabilities takes time, and that they're prioritised alongside other capabilities to address the highest risks to the integrated force first.'
Working in a US-led, global environment brought challenges, such as simultaneously coordinating and prioritising effects across the multiple combatant commands (all operating on different battle rhythms and with different mission needs), tasking vast numbers of tactical units and overcoming cultural barriers to information sharing.
Group Captain Greening said interoperability in coalition operations went beyond systems and software.
"In the human dimension, trust is everything," he said.
"Long-term commitments in key positions build the deep trust and confidence that enables nations to operate effectively together."
Group Captain Greening said the award reflected Australia's growing role in space operations. Years of investment in training and access to US programs had enabled the ADF to make meaningful contributions.
He hoped it would encourage more Defence personnel to explore opportunities in the US Military Personnel Exchange Program and Space Command roles.
To the next generation of Defence space professionals, his advice was clear: patience and perspective.
"Understand that delivering space capabilities takes time, and that they're prioritised alongside other capabilities to address the highest risks to the integrated force first," Group Captain Greening said.
"Be aware of Government direction, our strategic space related documents, and the intent of our allies - remember, actions in space can have strategic consequences."
Reflecting on his time, Group Captain Greening said the operational experience was invaluable, but it was the enduring relationships that left the greatest mark.
"Seek out overseas exchange or liaison roles, they broaden your perspective and strengthen the partnerships that make mission success possible," he said.
