In the afterward of Variable Star, Spider Robinson talks about the dangers inherent in attempting to write a novel based on the notes of someone else, especially when that someone else is Grand Master Robert Heinlein (not to be confused with Grand Master Flash). Robinson's friendship with Heinlein served as both a blessing and a curse, according to the afterward; he thought writing the novel a fitting tribute to Heinlein and would never have gotten the opportunity had he not been a friend of the family. However, he also recognized the expectation that, as someone recognized for knowing and admiring Heinlein and writing in his style, he would channel Heinlein-that he somehow would write the book Heinlein never got to. Towards the close of the afterward, Robinson talks about a conversation with the literary executor, in which Robinson is told to make it the "best Spider Robinson book" he can, and he admits he feels he has done so. Unfortunately, the marketing of the novel seems to do the opposite, describing the book as something like a séance for Heinlein, with the spirit gently possessing Robinson so that Heinlein speaks again.
So, depending on what you know as you approach the book, it is either a flawed attempt at being Heinlein or a flawed novel by Robinson. And even if you accept that Robinson is being Robinson, the novel spends a lot of time kissing Heinlein's literary butt. Perhaps Robinson does this in all of his novels, but the references to the Heinlein mythos are staggering in their number and … well, smarminess.
For example, the main character is a farmer from Ganymede, in a winking reference to Farmer in the Sky. At an emotional low-point in the book following a massive disaster, a character reminds the rest of the passengers on the ship about Nehemiah Scudder (from Heinlein's "If This Goes On--") and his rise to power. In the same passage, a reference is made to Leslie LeCroix, the first man on the moon in some of Heinlein's stories. There are even puns on titles of books, including a particularly clunky one on The Rolling Stones. So, even if this is Robinson at his best, it is inextricably interwoven with Heinlein, and not necessarily to the betterment of the part of the book that is Robinson.
Of that part of Variable Star that is Robinson, not very many good things can be said. Adopting the narrative style of juvenile novels (of which Heinlein was a master), we observe Joel Johnston as he approaches maturity, studying him in his non-maturity and following the events that cause him to become an adult. But the weakness here is that the Joel's circumstances are so contrived that they are nearly unacceptable, even for a science-fiction novel. Joel's mother died soon after his birth, and his father (a Nobel Prize winner in physics) was the perfect parent. When his father dies, Joel finds himself on Earth working on an education as a composer and musician. The novel opens when Joel and his betrothed have a horrendous argument about the potential of their wedding happening soon and goes downhill from there. Joel finds out that Jinny Conrad is actually the grand-daughter and heir to the Solar System's wealthiest man, and he is being groomed to help run the financial empire, no matter what he wants for himself. Joel goes on a bender and awakens to find himself aboard a colony ship headed to a star 20 light-years from Earth.
The rest of the novel is spent on board the ship as Joel is forced to undergo the lessons that his peculiar status until then had allowed him to miss. We get to meet Joel's friends and companions, all the while Robinson fills in the information about the setting. Swerving around the Heinlein references, we find out that that the ship is basically powered by Zen individualists who have a fondness for Joel's saxophone playing. But if the novel is meant to exhibit a man pulling himself up, it misses its intention since Joel seems to be the luckiest man on the ship. When he realizes he has gone aboard the ship with no liquidity, he discovers that an option his father had left for him has come through and he is extremely wealthy. And, oh by the way, the ship's banker becomes a great friend in the process of giving Joel the happy news. In fact, Joel rarely meets any one on the ship who doesn't like him-the one character there who is uncertain of him is more terrified of Joel's father's reputation than anything he knows about Joel. Even after he gets into a fight with two of the ship's toughs, they eventually become valued comrades.
And, as is the way with such novels, when Joel reaches some sort of maturity, it is put to the test by calamity. However, in this case, the calamity is so huge that it literally beggars the credulity of the reader; Sol is destroyed, wiping out the entirety of the Solar System and leaving the fate of humanity on Joel's ship and the other colonies being established. And then, as the effects of that sink in, Zen fails the ship and its propulsion unit is lost, stranding the ship as it is moving at near-light speed, destined to flash by its target planet without the ability to stop or even slow down. But taking a step back as a reader, this calamity strikes with about 60 pages left in the 300+ page novel. In about a fifth of the novel, somehow this is going to be worked out, and unless Robinson pulls a god out of the machine, it's going to have to be resolved from the cast of characters we already have at that point. From there it is only an exercise in logic to figure out the ending, making it feel extraordinarily contrived.
And, speaking of contrived, I need to go back to the speech about Nehemiah Scudder. Robinson grafts current world history onto the Heinlein history by explaining the root causes of Scudder's rise to power. Unfortunately, he uses the events of 9/11 and the resulting wars in Iraq and Afghanistan to deliver a heavy-handed sermon about the failure of the American people in their current crisis. I found this particular passage insulting and well out-of-place. It only served as a distraction from the flow of the novel as the character paraphrases FDR: "The only thing we have to fear is fear itself." While I happen to agree with political stance of the speaker, it just didn't work in this novel.
So, which is it? Tribute to Robert Heinlein or an attempt to evoke his spirit? Whichever is the case, the novel follows the familiar pattern of he coming-of-age novel, but it misses on the details. Joel doesn't have much adversity to rise out of, and what he does escape, he usually escapes with a lot of help from a large cast of characters. While it may evoke Heinlein in its broad strokes and allusion, I much rather point to Robinson's essay "Rah! Rah! R.A.H." in the posthumous Heinlein collection, Requiem. This book is okay for Heinlein completists; in fact, it might actually be a fun wink to the Golden Age of science fiction if it had all of its Heinlein trappings removed. But unless you are looking for one of those niches to fill, there are better ways to spend your reading time.