This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)., We investigate the initiation of four lightning flashes detected from ground by means of the Colombia Lightning Mapping Array (Colombia-LMA) and simultaneously observed from space by the optical sensors of the Atmosphere-Space Interactions Monitor (ASIM) on board the International Space Station (ISS), the Geostationary Lightning Mapper (GLM), and the Lightning Imaging Sensor on the ISS. The initiations of the flashes are characterized by isolated and predominant optical blue pulses (337.0 nm). In three of the flashes, red emissions (777.4 nm), a dominant line of hot lightning, were not detected during their initiation. In these cases, the initiations were also accompanied by bipolar VLF/LF waveform with a narrow short duration (<40 μs) and VHF emissions with high radio frequency power (<269 kW). The detection of the blue emissions without any red luminosity supports that the fast breakdown processes at the flash initiation can be exclusively of streamer nature. The onset of the fourth flash was associated with both blue and red radiation, and with weak narrow bipolar waveform in VLF/LF and low VHF power. The flashes initiated between the midlevel negative and upper positive charge regions. This paper presents and discusses the first fast breakdown processes observed simultaneously from ground by means a Lightning Mapping Array (LMA) and from space during the onset of lightning flashes. © 2021 The Authors., The UPC contribution: This work was supported by research Grants ESP2013-48032-C5-3-R, ESP2015-69909-C5-5-R and ESP2017-86263-C4-2-R funded by MCIN/AEI/ 10.13039/501100011033 and by “ERDF A way of making Europe”, by the “European Union”; and Grant PID2019-109269RB-C42 funded by MCIN/AEI/ 10.13039/501100011033. The IAA contribution: This work was supported by the Spanish Ministry of Science and Innovation, Ministerio de Ciencia e Innovación (AEI) under project PID2019-109269RB-C43 and the FEDER program. FJPI acknowledges the sponsorship provided by the Federal Ministry for Education and Research of Germany through the Alexander von Humboldt Foundation. AL was supported by the European Research Council (ERC) under European Union Horizon 2020 Framework Programme/ERC Grant Agreement 681257. Authors FJGV, FJPI, and AL acknowledge financial support from the State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofísica de Andalucía (SEV- 2017-0709). The UV contribution: This work was supported by research grants from the Spanish Ministry of Economy and the European Regional Development Fund (FEDER): ESP2013-48032-C5-1-R, ESP2015-69909-C5-1-R and ESP2017-86263-C4-1-R. The UB (University of Bergen) would like to thank the Research Council of Norway under contracts 223252/F50 (CoE). The USP (University of Sao Paulo) contribution: This work was supported by Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)— Print Project (grant number: 88887.370081/2019-00). ASIM is a mission of The European Space Agency (ESA). The project is funded by ESA and by national grants of Denmark, Norway, and Spain. We thank Keraunos(Colombia) for the LINET data., Peer reviewed