Cheng composed the initial idea for the novel in 2012, after seeing a photo of the Pale Blue Dot, and was further inspired by a road trip he took in 2013.

After a failed attempt to enter the University of Michigan Business School, he attended classes about communications, and went to New York City in 1998 for an advertising internship.

[4] Cheng recalled that part of the novel was based on a road trip he took in the Southwestern United States in mid-2013, where he mimicked his late father who once took a Greyhound Lines service from Los Angeles to Detroit, wanting to know the full story of his family "and how I came to be where I am".

[5] Cheng researched topics of social work and child protective services, some of the main plot points of the novel, with the help of several friends.

When Alex is discharged, everyone but him learns that Karen has long suffered from schizophrenia and is transferred to a New Jersey mental ward after going out nude.

After days of uncertainty, Ronnie reveals to Alex that Joseph was an abusive husband, however Karen's disorder blinds her of the situation.

According to their analysis, "Reading Alex's missives [...] gives us insight into a child's desire for connection, the value of correspondence (in whatever form it takes), and the potential for the things that we write and say today to inform the understandings of future audiences.

[1] On May 2, a group called the Young at Heart Bookgroup hosted an adult-only discussion of the book with Cheng at Anderson's Bookshop in Downer's Grove.

[8] The audiobook stars Kivlighan de Montebello as Alex, Brittany Pressley as Terra, Graham Halstead as Steve, Michael Crouch as Ronnie, and Jason Culp as Zed, with additional narration provided by Thérèse Plummer, Susan Bennett, Dan Bittner, Pete Larkin, and Courtney Shaw.

[8] During the COVID-19 pandemic, Cheng posted YouTube videos of him reading chapters from See You in the Cosmos to guide those on remote learning.

[10] The "enticing" and "heartwarming"[11] See You in the Cosmos, regarded a "Sweet, quirky road story sparkles with warmth and wisdom" by Darienne Stewart of Common Sense Media (who gave the novel five out of five stars),[12] received generally positive reviews, lauded as "sweet [and] soulful" of a debut,[13] with glimmers of poignancy and humor.

[15][16] Numerous reviewers such as Entertainment Weekly (who gave the novel a B+), The Chicago Tribune, and Book Riot found Alex's stubborn yet optimistic personality that colors the novel as to how the novel astounds them,[17][15][16] making it "Riveting, inspiring, and sometimes hilarious".

[13] "Meghan Cox Gurdon, writing for The Wall Street Journal, reckoned that "Some readers ages 10–15 may find that Alex's star-struck naiveté gets a bit grating, but those who don't will discover much that rewards in Jack Cheng's life-embracing, stream-of-consciousness tale of family lost and found".

[18] Alex is regarded to have a memorable and resonating bundle of emotions; The New York Times Book Review's Natalie Standiford elaborated, "If extraterrestrials ever did find his Golden iPod, they would think Earthlings were wonderful.

"[19] The transcript style of narrative is also praised by many, remarked "a brilliant, refreshing structure":[13] "An odd medium that sounds like it would be confusing but really works".

[13] It is seen as a subtle trick to transition between its quirky and deep moments,[17] as well as an effective tool to indulge readers into the characters' misery.

[19] Deborah Stevenson of The Bulletin of the Center for Children's Books, however, noted that the space the transcript takes—exacerbated by the many plot elements in play—causes the vital subplot of the loss of Carl Sagan untouched.

The audiobook's episodic narrative is also said to "make it easy to suspend disbelief and renders this an altogether captivating listening experience.