Not yet, but after we finish Apologia anatomy, we already have astronomy ready to go.
What about letters to Nasa, buying space food, playing space games, make a model of a solar system, map out the distance to the sun using pennies to stand for like say 10 miles each or something? Look up space themed websites. Make one of those pin hole viewing box. Find out what is going on in the real sky at different times... meteor showers...planets close enough to see... eclispes, etc. Look up their birth year and see if anything exciting happened the year they were born.... use a flashlight to represent the sun and show how it shines on the earth and the other half is dark... discuss and demonstrate planetary rotation and such. Do you have a space themed museum nearby?
Physics of space. They coud learn the difference between matter and weight. My kids loved calculating their weight on different planets. You could make it into a science and math lesson. Albert einstein for kids is a great book. Look up recent experiments. There is a recent story how scientist got sound waves to go the speed of light. My son once did the moon phases using oreoes. Have fun!
We have been doing space for close to two months now. DS got interested and we just keep finding things to watch and do. I have a list of Youtube videos, books we have read, movies we have watched and experiments we have done.
Venus, Mercury They have all of the planets in this series. Just look up space school on Youtube
Magic Tree House: Midnight on the Moon and accompanying Resource book, Picturpedia: Space, The Near Planets, The Far Planets, Magic School Bus:Lost in the Solar System
Magic School Bus: Gets Lost in Space, MSB: Out of this World, MSB: Sees Stars, How to Make a Planet (Science Channel)
Also, we got the Magic School Bus Space Kit for the experiments
We made clay planets out of different colors of play-do, baked them and hung them as a mobile. We were using Considering God's Creation for science at the time and they had a lot of really good hands on activities for space, including a cool "projector" craft for viewing the stars using a shoebox and a flashlight.