The Outhouse reveals exactly whom the new Smasher's grandfather is.
Avengers #5 revealed the origin of Isabel Dare, a new human Imperial Guard member. One of the character's subplots revolve around the character's grandfather, a grumpy old man with some sort of connection to Steve Rogers and a mysterious past.
So who is Izzy Dare's grandfather? Keen eyed Brits might recgonize him as Dan Dare, a British science fiction comic book character who has appeared in the Eagle and 2000AD magazines. Dan Dare is a British equivalent to Buck Rogers and served as an inspiration for Captain Jack Harkness of Doctor Who fame among others.
Dan Dare has been hailed as an inspiration to many influential comic book writers. Both Chris Claremont and Warren Ellis refer to Dan Dare as one of their earliest influences and one can point out some of the sci-fi elements shared between Claremont's first X-run and various Dan Dare stories. Ellis, meanwhile, has written several characters based on Dare (such as Dan Dashwood in Ministry of Space) and even wrote a Dan Dare miniseries published by Virgin Comics back in 2008. Grant Morrison also wrote an iteration of Dare in the pages of Revolver, which featured a grim and gritty Dare blowing up London with a nuclear bomb.
Dare was briefly referred to in Marvel's Captain U.K. line, where a Captain "Roy Risk" from Earth-238 had been killed by the Fury.
Of course, Hickman can't openly call the character Dan Dare, since Marvel doesn't appear to have rights to the character. Currently Dan Dare can be found in the pages of Spaceship Away, a British small press comic available mainly by mail order.