Ironically, the internet was down on the evening of Ada Lovelace Day 2015, an annual, international 'celebration of the achievements of women in science, technology, engineering and maths (STEM)', so I couldn't post at the time. Belatedly, the people whose achievements I've admired are:
Professor Monica Grady, whose joy when the probe Philae successfully landed on the Rosetta comet is just about the most wonderful thing on the internet (and she worked on one of the instruments on board, which is very cool). Like New Horizons sending back images of Pluto, it's a reminder of the awe-inspiring combination of planning, foresight, science and engineering in space that has made 2015 so interesting.
Finally, I love this image of Margaret Hamilton, lead software engineer on Project Apollo (1969), with some of the Apollo Guidance Computer (AGC) source code.