Mars Book vs X
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Mars Book
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The Mars Book is an app that is dedicated for observing Mars which will make close approach in summer 2020. Mars will come close to Earth from September 2020 through October 2020. Closest approach will take place on October 6, 2020. Mars Book is a highly useful Mars observing app which will indicate the location of Mars visible in the sky. It shows you why Mars Close Approach will take place, and it is explained readily using animated illustrations and star charts at a viewpoint from outer Space. Mars Close Approaches taking place 23 times from the year 2003 through 2050 will be displayed and apparent retrograde motion of Mars will be displayed. Enjoy Mars Close Approach this summer with the Mars Book app!
X
Explore the solar system, Earth's atmosphere, and its structure with engaging audio and video content. This app offers an entertaining and educational journey for all ages, created by a team of experts.
- Audio guides for Solar System Trail
- On-demand content
- Audio and video on Earth's atmosphere
- Content on Earth's structure
- Solar System exploration
- Expert-created content
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Use the free Audio Guides and add another dimension to the Solar System Trail walk or enjoy the on-demand content. The App offers audio and video content about The Atmosphere, The Structure of the Earth and The Solar System. It is the collaborative work of scientists, writers, space artists and voice actors. Its aim is to deliver fun, entertaining and educational content to suit younger and older users alike. Get a new perspective as you go on a journey across the Solar System, fly to the top of the Atmosphere or descend on a Journey to the Center of the Earth.
Screenshots
Verdict
The clearest difference is in-app purchases: Mars Book at none against X's 10. Mars Book also leads on iOS requirement (9.0 vs 15.6). X's advantage is update cadence (every 3 months vs every 13 months). On price, ads and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
Both are free to download. X sells 10 one-off in-app purchases. Mars Book asks for nothing beyond the download.
Mars Book ships an update every 13 months, X every 3 months. The most recent releases landed on October 13, 2026 and October 24, 2026 respectively.
| Parameter | Mars Book | X |
|---|---|---|
| Price | Free | Free |
| Rating | — | 1.3 (3 ratings) — better |
| Positive reviews | — | 0.0% of reviews |
| Number of ratings | — | 3 — better |
| Update frequency | Every 13 months | Every 3 months — better |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | — | Free |
| Devices | iPhone, iPad, iPod — better | iPhone, iPod |
| Requires iOS | 9.0 — better | 15.6 |
| Further details — not scored | ||
| Size | 14 MB | 46 MB |
| Age rating | 4+ | 4+ |
| Developer | Vixen Co.,Ltd. | Roni Waserman |
In-app purchases
Mars Book
No in-app purchases
X
- A Comet's Journey$0.99
- Journey To The Centre Of Earth$0.99
- A Mission To Mars$0.99
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- A Mission To The ISS$0.99
- A Voyage To Saturn$0.99
- Solar System Experience$0.99
- The World Under Our Feet$0.99
- Tour The Atmosphere$0.99
- When Dinosaurs Moved$0.99
- Moons Of The Solar System$0.99
