What reading level is Gravity buster?

Gravity buster by Frank Asch is at a Level 3-4 reading level (Lexile 670L). Recommended for Lower Grades readers (Ages 5-8).

What age is Gravity buster appropriate for?

Gravity buster is recommended for Ages 5-8. HootRating: 8LE (Light — Emotional).

What genre is Gravity buster?

Gravity buster is fiction — Juvenile Fiction.

Does Gravity buster have any content warnings?

Gravity buster has a HootRating of 8LE (Light — Emotional). No specific content flags noted. On HootRated, every book is rated across four dimensions — emotional, physical, social, and thematic — to help parents make informed choices.

How many pages is Gravity buster?

Gravity buster by Frank Asch is 143 pages.

Reviewed by HootRated editorial · Last updated May 18, 2026

Gravity buster

Frank Asch

Gravity buster

Age Rating, Reading Level & Content Guide

Journal #2 of a Cardboard Genius

by Frank Asch

Reading Level 3-4 8LE Ages 5-8 Balanced Read

The text is written at a 3rd grade reading level, the subject matter is intended for younger children (ages 5–8), and the content is gentle with no concerning themes.

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About This Book

The hum of the spaceship fills the air, vibrating through your fingertips like a secret song. Alex and Zoe Breen feel the excitement tingling in their toes as they prepare to zoom past Jupiter’s swirling storms. But saying goodbye to little brother Jonathan makes this adventure feel even bigger and braver.

Themes

FamilySpace AdventureSibling RelationshipsJuvenile Fiction

Quick Assessment

This early reader book follows siblings Alex and Zoe Breen as they embark on a space adventure near Jupiter while navigating the feelings of leaving their younger brother Jonathan behind. Suitable for ages 5-8, it combines themes of family bonds and space exploration with accessible language for emerging readers. There is no intense content, making it appropriate for young children.

Why we rated Gravity buster 8LE

Gravity buster is written at a Level 3-4 reading level with a Lexile measure of 670L across 143 pages. Strong independent readers around grade 4.5 can typically handle this book on their own; with parent or teacher support, Gravity buster works for readers up to grade 5.5.

We rate Gravity buster as 8LE ("Light — Emotional") because the content sits in the "Gentle" range — no conflict beyond everyday childhood experiences. Across our four dimensions (emotional, physical, social, thematic) the book reads as evenly gentle; no single dimension stands out as a concern.

No specific content flags were raised by community reviewers, which is consistent with the gentle intensity score.

Thematically, Gravity buster explores family, space adventure, sibling relationships, and juvenile fiction — these threads give the book room to mean different things to different readers.

Good fit for

✓ Children in the Ages 5-8 range — the maturity and attention span match the story's pacing.
✓ Patient readers who enjoy slower, character-driven stories.
✓ Kids drawn to stories about family, space adventure, sibling relationships.