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We show that it is possible to combine an early phase of String Gas Cosmologywhich can explain the origin of the observed structures on cosmological scaleswith a short later period of power law inflation which creates spatialflatness. The resulting model is consistent with the ``swampland criteria'' andthe constraints coming from the {\it Trans-Planckian Censorship Conjecture}.Such a construction is not possible using only canonical slow-roll inflation,but it can emerge in the warm inflation scenario or in cold inflation with anexponential potential. The resulting cosmology is non-singular. We discuss thespectrum of cosmological perturbations resulting in our scenario. On largescales (scales which remain larger than the Hubble radius after the initialstring gas phase) the spectrum is determined by the thermal string gasfluctuations set up in the primordial phase, and it is almost scale-invariantwith a slight red tilt. On small scales, the perturbations produced during theinflationary phase dominate. On these scales, the spectrum is once again nearlyscale-invariant. There is an intermediate range (scales which enter the Hubbleradius during the period of inflation) where the string gas fluctuations aredamped but continue to dominate over those produced during the period ofinflation. On these scales the spectrum has a sharp red spectral index of $n_s- 1 \sim -2$.

Creating Spatial Flatness by Combining String Gas Cosmology and Power Law Inflation