LCP
Largest Contentful Paint
4.3s
Poor
Good: < 2.5s
Measures how long it takes for the main content to appear on screen
Eliminate Unused JavaScript and Legacy Code
How to optimize spacex.com
Eliminate Unused JavaScript and Legacy Code
Medium Impact+6 points estimated
Why It Matters
96KB of unused JavaScript in vendor bundle delays both FCP and LCP by 450ms while legacy polyfills add unnecessary bloat.
How to Fix
Use webpack-bundle-analyzer to identify unused code in your vendor bundle and implement tree-shaking. Remove Object.create and Object.getOwnPropertyDescriptor polyfills as they're supported in all modern browsers. Consider code splitting to defer non-critical JavaScript execution.
0Needs Improvement
What This Score Means
A score of 83 falls in the "Needs Improvement" range (50-89). While it is better than poor (0-49), you should aim for 90+ to provide an optimal user experience and maximize SEO benefits.
This site is slower than approximately 35% of similar sites. The main issues affecting performance are image optimization, JavaScript execution time, and layout stability.
Addressing these issues could improve your conversion rate by 15-20% and boost your search engine rankings.
Core Web Vitals Analysis
INP
Interaction to Next Paint
138ms
Good
Good: < 200ms
Measures how quickly the page responds to user interactions
CLS
Cumulative Layout Shift
0.00
Good
Good: < 0.1
Measures visual stability - how much content shifts during page load
AI Performance Analysis
This SpaceX website has good but not great performance with a score of 83/100. The biggest problem is enormous video files (over 15MB total) that are severely slowing down page load times, causing the Largest Contentful Paint to take 4.3 seconds - much longer than the recommended 2.5 seconds. The site would benefit significantly from compressing these large video files, implementing better caching strategies (currently only 12 hours), and optimizing oversized images that are being served at much higher resolutions than needed. These improvements could easily push the performance score into the 90s and provide a much faster user experience.
Other Optimization Recommendations
Optimize Video and Cache Strategy
High Impact+12 points estimatedWhy It Matters:
Large video files (13.8MB) have inadequate caching (12 hours vs. recommended 1 year) causing repeated downloads and delaying LCP by 1.4 seconds.
How to Fix:
Configure your CDN to set cache headers for video files to 1 year (31536000 seconds). Implement video compression to reduce file sizes by 50-70%. Consider using adaptive bitrate streaming for mobile devices to serve appropriately sized video content.
Preconnect to Critical Third-Party Origins
High Impact+8 points estimatedWhy It Matters:
Missing preconnections to content.spacex.com and sxcontent9668.azureedge.us add 730ms of network delay to critical resources.
How to Fix:
Add <link rel="preconnect" href="https://content.spacex.com"> and <link rel="preconnect" href="https://sxcontent9668.azureedge.us"> to your HTML head. This allows the browser to establish connections early, reducing the 4.3-second LCP by up to 730ms.
Keep Your Site Fast After Optimization
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Related Performance Analyses
More Generic Speed Tests
Generic Performance Resources
Optimize LCP Image Discovery
The LCP image is not discoverable in initial HTML, causing delayed loading and poor performance.
Remove Unused JavaScript Code
280 KiB of unused JavaScript wastes bandwidth and delays LCP by 1.5 seconds.
Eliminate Render-Blocking JavaScript
Render-blocking scripts delay First Contentful Paint by 11.2 seconds, severely impacting user experience.
Fix Forced Layout Reflows
JavaScript is causing 278ms of forced reflows that block rendering and hurt user experience.