Comparison

DLR COMETS vs Number Line

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

DLR COMETS

Explore the Rosetta mission to Comet 67P/Churyumov-Gerasimenko through an interactive exhibition. Discover the science behind comets and the historic Philae lander touchdown. Relive this exceptional spaceflight adventure with multimedia content.

Highlights
  • Interactive comet model
  • Mission highlights and photographs
  • Historical background on comets
  • Rosetta mission science
  • Philae lander touchdown details
  • Personal stories from the mission
Features
Read full description

The European Rosetta mission arrived at Comet 67P/Churyumov-Gerasimenko in August 2014 after a 10-year journey through space. Three months later, the Philae robotic lander touched down on the comet – the first probe to do so in the history of humankind. It was a fantastic scientific adventure and an exceptional spaceflight project. The German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt; DLR) takes you on a journey to the origins of the Solar System with this exhibition app “DLR COMETS - The Rosetta mission: Journey to the origin of the Solar System”. The centrepiece of the exhibition is a model of comet 67P/Churymov-Gerasimenko based on data from Rosetta’s OSIRIS camera system, surrounded by backlit photographs of the comet and mission highlights. Additionally to the historical and technical background on comets as important building blocks of the Solar System, the Rosetta mission and its scientific achievements to date, the exhibition includes film-clips highlighting the personal stories of the men and women that made Rosetta a reality and the deep emotions evoked by involvement in the mission.

About

Number Line

This app provides an interactive number line for educational purposes, enabling users to visualize numbers, perform various math games, and practice rounding. Its simple interface supports zooming, swiping, and marking numbers with pins or freehand drawing.

Highlights
  • Infinite number line visualization
  • Rounding practice (nearest 10, 100, 10,000)
  • Number comparison
  • Pinch-to-zoom functionality
  • Swipe navigation
  • Search for specific numbers
  • Pin marking
  • Freehand drawing tool
Read full description

An infinite number line to use in the classroom, with a simple design that allows for numerous maths games and challenges! • Ask the class to round to the nearest 10/100/10,000. • Visualise the size of numbers relative to one another, including negatives. How to use: • Zoom with a pinch • Swipe along the number line • Go to a number by typing in the search box • Drag and drop pins to mark numbers • Draw free-hand with the pen tool

Screenshots

DLR COMETS4 screens
Number Line1 screens

Verdict

The call

The clearest difference is review sentiment: Number Line at 100% against DLR COMETS's 0%. DLR COMETS's advantage is update cadence (every 3 weeks vs every 15 months) and iOS requirement (8.1 vs 13.0). On price, ads, in-app purchases and monetization model 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

CostPrice · In-app purchases · Ads · Monetization

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

UpkeepUpdate frequency

DLR COMETS ships an update every 3 weeks, Number Line every 15 months. The most recent releases landed on November 2, 2026 and November 3, 2026 respectively.

Scorecard3 real differences · 7 level
DLR COMETS versus Number Line: the parameters behind the verdict, then further details
ParameterDLR COMETSNumber Line
PriceFreeFree
Rating—5.0 (5 ratings) — better
Positive reviews0.0% of reviews100.0% of reviews — better
Number of ratings—5 — better
Update frequencyEvery 3 weeks — betterEvery 15 months
AdsNoNo
In-app purchasesNoNo
MonetizationFreeFree
DevicesiPhone, iPad, iPodiPhone, iPad, iPod
Requires iOS8.1 — better13.0
Further details — not scored
Size416 MB16 MB
Age rating4+4+
DeveloperDLR German Aerospace Center e.V.Blastoff Design

Customer experience

DLR COMETS

Written reviews2 reviews
Positive0.0%
Neutral0.0%
Negative100.0%

Number Line

All ratings4 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

DLR COMETS

No in-app purchases

None

Number Line

No in-app purchases

Questions

Is DLR COMETS free?
DLR COMETS is free to download, with no in-app purchases.
Is Number Line free?
Number Line is free to download, with no in-app purchases.
Do DLR COMETS or Number Line have ads?
Neither DLR COMETS nor Number Line shows ads.
Which is updated more often, DLR COMETS or Number Line?
DLR COMETS ships an update every 3 weeks, and Number Line every 15 months. Most recently, DLR COMETS was updated on November 2, 2026 and Number Line on November 3, 2026.

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