Lucien Rudaux Memorial Award for Lifetime Achievement in Astronomical Art, IAAA, 2003

Frank R. Paul Award for Outstanding Achievement in Science Fiction Art, Nashville, 1988

Award of Merit, Art Director's Club of Washington, DC, 1981

Hugo Award for Best Related Work, 2002: The Art of Chesley Bonestell

Award of Excellence in Science Writing from American Institute of Physics, 2003: Worlds Beyond series

Nominee for 1982 Hugo Award for best nonfiction for The Grand Tour

Ten Best Books of the Year, 1984 --Astronomical Society of the Pacific: Out of the Cradle

Ten Best Books of the Year, 1987 --Astronomical Society of the Pacific: Cycles of Fire

Outstanding Science Trade Book, National Science Teachers Assoc./Children's Book Council, 1987: Stars and Planets

New York Public Library Books for the Teen Age, 1992:  The History of Earth

IAF Manuscript Award. Booklist Editor's Award, 1994: The Dream Machines

New York Public Library Books for the Teen Age, 2000: Rockets

Children's Book Committee at Bank Street College Best Children's Book of the Year, 2005:  Venus

National Science Teachers Association (NSTA) / Children's Book Council (CBC) Outstanding Science Trade Books for Students K-12, 2005: The Elements

VOYA Nonfiction Honor List, 2009: Digital Art

2001 Writer's League of Texas Violet Crown Award for best audiofiction: Bradamant

2012 SSLI (Society of School Librarians International) Book Award, Honor Book in the Science 7-12 category: Is the End of the World Near? 

VOYA Nonfiction Honor List: Digital Art

NSTA/CBC Outstanding Science Trade Books for Students K-12: The Elements

Junior Library Guild Selection; nominee for Library of Virginia Literary Award for Non-Fiction: Recentering the Universe

Best Children's Books of the Year, Children’s Book Committee at the Bank Street College of Education: Curiosity's Mission on Mars

Finalist, Locus Award for Best Art Book, 2014: The Art of Space