Modi heads the Department of Space. He has every right to announce it whether you like it or not.
As far as overstating positions go, the opposition in India was quick to jump to conspiracy theories after the Pulwama attack saying that Modi orchestrated the entire attack for political gains. This ridiculous conspiracy theory mongering has gone on to unprecedented levels this election. After failing at making a dent for the past 1 year by parroting Rafale lies, the opposition is now trying to find a new issue to latch onto.
It can't be that you keep throwing darts until one of them sticks! That is not how a responsible opposition should behave!