Asteroid miner literally trips over egg-shaped alien battery

[Terence F.]

Lost the book a decade ago, but it was a hard sf novel set in the Solar System where a young asteroid explorer/miner finds an egg-shaped super-heavy alien artifact. He takes it to a woman who is a research genius based in the asteroid belt, who discovers it is a depleted power source for a star drive. Meanwhile on Earth, a military general is taking over the government and launching attacks on space-based population. The woman genius invents an FTL drive that allows the asteroid dwellers to leave the Solar System and avoid being conquered. It seems like this is actually a middle book of a trilogy, there is another book after that where they arrive at their destination and find another group of humans.

Any help or hints appreciated!

 

[Bick]

My problem with this one is that several references sound like Niven's known space, but I'm sure that's not it. In The World of Ptaavs, an asteroid miner finds an egg-shaped heavy alien object, and ultimately this sparks some tech advance, though not FTL, and in other known space stories asteroid miners leave the solar system and help populate new worlds... all of which means means I can't get known space out of my mind.