Karl Zeigfreid was a house name for Badger Books; in this case, R.L. Fanthorpe is the author. The cover artist is unknown, and the synopsis of the book makes it highly unlikely that a skeleton in a spacesuit holding what appears to be a South Seas dancing girl made an appearance. Skeleton astronauts are often seen on sci-fi covers, but rarely have anything to do with the stories inside.
2 Warps to Neptune 
>Skeleton astronauts are often seen on sci-fi covers, but rarely have anything to do with the stories inside.
This book has a skeleton astronaut cover that really is a part of the story.
http://www.goodreads.com/book/show/776489.Inherit_the_Stars