Joe Haldeman SF Gateway Omnibus: Marsbound, Starbound, Earthbound

From Book 1: Young Carmen Dula and her family are embarking on the adventure of a lifetime-they're going to Mars. But Carmen's rebellious streak leads her to venture out into the bleak Mars landscape alone, where she is saved by an angel. An angel with too many arms and legs, a head that looks like a potato gone bad-and a message for the humans on Mars: We were here first...