Nadia Savchenko's speech is expected to be characteristically defiant and highly political, says BBC Moscow correspondent Sarah Rainsford.
She denies directing artillery fire from a Ukrainian volunteer battalion at the Russian journalists in June 2014.
Her lawyers say the case is political and a guilty verdict is inevitable.
They are pinning their hopes on some kind of political deal between Moscow and Kiev, our correspondent adds.
The prosecution, which is seeking a 23-year prison sentence, said on Wednesday it had proven Ms Savchenko's guilt "beyond doubt" as the five-month trial in a Russian court in Donetsk nears its end.
They said Ms Savchenko, acting as a spotter, had deliberately directed mortar fire at the journalists in June 2014 out of "hatred" for all Russians.
The defence argues that she had already been captured by pro-Russian rebels at that point and so is innocent.
The Ukrainian government says Ms Savchenko was abducted by pro-Russian separatists and handed over to the Russian authorities.
But Russia says she crossed the border illegally, posing as a refugee, before being detained.
Nadia Savchenko openly accuses prosecutors of lying and regularly declares "Glory to Ukraine" to family and supporters in court.
She often wears traditional Ukrainian dress during court appearances and back in Ukraine has become a symbol of resistance to Russia.
But the trial is a reminder that the conflict between Ukraine's government and pro-Russian rebels is still far from resolved, despite a peace deal, our correspondent adds.