Colony in Space, from 1971, was the first Third Doctor adventure in space, after a sequence of earthbound adventures. The first episode is rather good, with the Time Lords manipulating the Doctor again, and Jo's surprise at entering the Tardis being one of the better "it's bigger..." scenes. Then I'm afraid I felt it lost its way in being padded out to six epsiodes. The danger signs are there when part two has exactly the same cliff-hanger as the part one! And, despite the valiant efforts of all actors, the sets and direction really fail to convey a convincing sense of the scale of this planet, of how far it is from one set of buildings to another. The Master gets in some good cackling and there are some tightly-choreographed fight sequences; but apart from that, nothing much really happens, and the moral message of the story is both plodding and muted.
Death to the Daleks, from 1974, also had good and bad points. This is Sarah Jane Smith's first space adventure (as Colony in Space was Jo Grant's) and we start off very well with her in a bikini. The set looks properly like an alien planet. The Exxilons are memorable aliens (and I reckon one of them is still wandering around the Tardis). The Daleks are well voiced by Michael Wisher, who was to become Davros a year later. The plot, unfortunately, has huge holes, and the Daleks' plan (as usual) makes no sense at all. Wood and Miles identify the cliff-hanger at the end of Episode Three as the weakest in the history of the show, adn they have a point.
I see that both were directed by Michael Briant (who also did The Sea Devils, The Green Death, Revenge of the Cybermen and The Robots of Death); I think I would have guessed if I hadn't known.