After completing her PhD Bunn joined the Science Museum, London as a Researcher and Developer of exhibitions. She joined the Natural Environment Research Council as coordinator of Earth Observation Science in 2000. She was made Head of Earth Observation Future Missions in 2002. She joined Department for Environment, Food and Rural Affairs as Location Programme manager. Bunn joined the UK Space Agency in 2011. She led the International Charter for Space and Major Disasters from 2011 to 2012. The charter forces the international community to provide satellite imagery immediately after a disaster. She brokered the international agreement that ensured countries share satellite imagery after the MH370 disappearance. She explored how satellite imagery can be used to save lives. She formed a collaboration with the Italian Space Agency to share COSMO-SkyMed data. In 2014 Bunn was appointed Director of Policy of the UK Space Agency. She delivered the Reinventing Space Conference keynote lecture in 2014. She led the security, regulation, communications and international engagement. She advised on civil space activities to the Minister for Universities, Science and Cities. In 2014 she was featured in Marie Claire as one of their Top Women. She was elected to the Space Foundation Board of Directors in November 2015. She led the space aspects of the Global Monitoring for Environment and Security program, which encouraged Europe to monitor and protect the environment. She hoped that Tim Peake's mission to the International Space Station would encourage people to invest in space travel. She was appointed Vice Chair of the European Space Agency in 2017. She collaborates closely with France, and signed a joint statement to increase cooperation with CNES in January 2018. The collaboration will continue in spite of Brexit. She oversaw the collaborative agreement between Surrey Satellite Technology, Goonhilly Satellite Earth Station and the European Space Agency for commercial lunar missions. Throughout her career Bunn has been in programs to encourage students to engage with space missions. She collaborated with the WISE Campaign to create a set of classroom resources based on the space sector to encourage primary school children to study physics. She developed a space badge for Girlguiding. She has spoken at the World Economic Forum. She will be speaking at the National Space Symposium in 2018. She spoke at the 2017 Global Space Congress and TEDx London in 2018.