SOLVED. SF mid grade; two boys travel in robot spaceship that takes them to planet to make a deal. [s]

[Robert]

Read this to my daughter in 2006-07 from the library. She was in 2nd or 3rd grade. Two boys accidently take off in uncle, grandfather's (?) spaceship in the backyard. It is controlled by a robot or artificial intelligence. It takes them to two planets one with abundant water and the other dry. They realize the potential to make a deal and do so using the skills for negotiating they picked up from their uncle, grandpa, dad (?). You don't understand what the ship is doing until near the end. It was obeying the boys all along.

[Robert]

bump

[Kris]

The Accidental Spaceship by Gene Hunt?

Roberts, is this a picture book (about 32-48 pages) or a chapter book with mostly words?

Are the two boys brothers or friends/neighbors?

[Robert]

You found it! Thanks a million!!!

[Kris]

Great! Glad you found your book. I got lucky with the advanced search on www.worldcat.org (which is great for older children's books):

Keyword: spaceship backyard grandfather | Year: 1970-2010 | Juvenile | Fiction | Book | English