Results of ground-based VLBA observations of the quasar 3C 273 made at 15 GHz (top, 2013 February 10, peak intensity 3.2 Jy/beam, noise level 1.4 mJy/beam, beam size 1.21 × 0.53 mas) and 1.6 GHz (bottom, 2011 August 18, peak intensity 9.6 Jy/beam, noise level 2.2 mJy/beam, beam size 10.6 × 4.4 mas). Left: total intensity pseudo-color and contour images with the beam shown at the half power level in green. Contours start at 0.25% and 0.07% of the peak intensity and are plotted with ×2 steps at 15 and 1.6 GHz, respectively. The yellow lines in the 15 GHz image show the range of position angles of ground-to-space RadioAstron baselines covered by our observations: 10°, −8°, −38°. Right: corresponding interferometric (fringe) amplitude vs. projected baseline.