# Mars Book vs Cosmos

The clearest difference is update cadence: Cosmos at daily against Mars Book's every 13 months. Mars Book's advantage is device support (3 vs 1) and iOS requirement (9.0 vs 17.0). On price, ads and in-app purchases there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Mars Book ships an update every 13 months, Cosmos daily. The most recent releases landed on October 26, 2026 and November 4, 2026 respectively.

## The numbers

| Metric | Mars Book | Cosmos |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 13 months | **Daily** |
| Monetization | — | Free |
| Size | 14 MB | 67 MB |
| Requires iOS | **9.0** | 17.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Vixen Co.,Ltd.](https://appshunter.io/developer/536188843) | [Salih Yusuf Goktas](https://appshunter.io/developer/1693054465) |

## What reviewers say

### Mars Book

[App page](https://appshunter.io/ios/app/mars-book/id1342509724)

**In-app purchases:** none


### Cosmos

[App page](https://appshunter.io/ios/app/cosmos-our-solar-system/id6480411273)

Explore our solar system with realistic 3D models of planets. Discover detailed information about atmospheric compositions, surface features, and fascinating facts. An interactive journey for space enthusiasts and curious learners.

**Highlights:** Realistic 3D planet models, Detailed atmospheric and surface information, Captivating animations, Engaging exploration interface, Fascinating space facts

**Features:** macOS Compatibility, Vision Pro support

**In-app purchases:** none


## Frequently asked questions

### Is Mars Book free?

Mars Book is free to download, with no in-app purchases.

### Is Cosmos free?

Cosmos is free to download, with no in-app purchases.

### Do Mars Book or Cosmos have ads?

Neither Mars Book nor Cosmos shows ads.

### Which is updated more often, Mars Book or Cosmos?

Mars Book ships an update every 13 months, and Cosmos daily. Most recently, Mars Book was updated on October 26, 2026 and Cosmos on November 4, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*