W. E. Johns 
To Worlds Unknown [EPUB ebook] 

The Tavona and its crew of intrepid heroes, led by Tiger Clinton, are back and exploring the galaxy once again.On a routine trip to Mars, a chance visit to a new planetoid leads to kidnap! Another planet is populated entirely by identical twins. Even simple streams are not as they appear, and everything holds hidden and unexpected dangers.Using their wits, their skills, and with the help of friends made on their travels, Tiger Clinton and his team are ready to face anything — and they’ll have to!