I'll admit that I'm not a big fan of the Olsen Twins but I thought the well known faces might be a draw for reluctant readers.
I expected the dialog to be 'cool' and a slang-filled but in fact the English used is clear and concise and quite pleasant to read.
My objections were due to the frenetic pace and ridiculous plot that had two small girls solving a mystery that ,allegedly, baffled hundreds of NASA scientists.
But apart from that it has the classic ingredients of annoying but ultimately dependable siblings, friendly adults and a charming pet.
Not a bad story if you like that kind of thing.