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Results for https://www.nasa.gov

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United Stated United Stated · Santa Clara Completed: Apr 6, 2026 15:09 UTC

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C72

Site Health

Score: 72 / 100 1

Based on 8 categories, 0 sections

How is this calculated?

The overall score is a weighted average of individual category scores. Categories with more impact on user experience and security carry more weight.

Performance 25%Security 25%Accessibility 15%SEO 10%Infrastructure 10%Compliance 8%Content 5%Sustainability 2%

Weights reflect general web best practices. Individual needs may differ.

Top Priorities (5)

1

Content-Security-Policy header is missing

Security › Security Headers
2

No Content-Security-Policy header found

Security › Content Security Policy
3

Page weighs 16.3 MB (9.0 MB transferred)

Performance › Page Weight Budget
4

18 link(s) with no accessible text

Accessibility › Link & Button Quality
5

23 image-only link(s) without alt text

Accessibility › Link & Button Quality
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Recent Trends
Performance stable →
46
TTFB stable →
15ms
FCP stable →
1.9s
LCP stable →
4.4s

Lighthouse Scores

Industry-standard audits powered by Google Lighthouse.

46 -4
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
89
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
96
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
100
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

Core Web Vitals

Key metrics that affect user experience.

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

1.90 s

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

4.43 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

1.01 s

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.268

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

3.66 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

34.28 s

Detailed Report

Audit breakdown by category with detailed findings.

46

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Layout shifts occur when elements move absent any user interaction. Investigate the causes of layout shifts, such as elements being added, removed, or their fonts changing as the page loads.

headings: [map[key:node label:Element subItemsHeading:map[key:extra] valueType:node] map[granularity:0.001 key:score label:Layout shift score subItemsHeading:map[key:cause valueType:text] valueType:numeric]]
items: [map[node:map[type:text value:Total] score:0.268257] map[node:map[boundingRect:map[bottom:1100 height:314 left:24 right:388 top:786 width:364] lhId:page-1-DIV nodeLabel:Join us for continuing live coverage of Artemis II, the first crewed mission of… path:1,HTML,1,BODY,8,MAIN,0,ARTICLE,0,DIV,0,DIV,0,DIV,0,DIV,1,DIV,0,DIV selector:div.hds-nasa-live-main > div.grid-container > div.hds-nasa-live-three-column-row > div.hds-vertical-align snippet:<div class="hds-vertical-align grid-col-12 desktop:grid-col-3 padding-right-0 desktop:…"> type:node] score:0.172599 subItems:map[items:[map[cause:Unsized image element extra:map[boundingRect:map[bottom:66 height:50 left:176 right:236 top:16 width:60] lhId:page-14-IMG nodeLabel:NASA Logo path:1,HTML,1,BODY,3,HEADER,0,DIV,1,DIV,0,A,0,IMG selector:div.usa-nav-container > div.grid-col > a#mobile-header-logo > img snippet:<img fetchpriority="high" width="60" height="50.58" alt="NASA Logo" src="https://www.nasa.gov/wp-content/themes/nasa/assets/images/nasa-logo.svg" srcset="https://www.nasa.gov/wp-content/themes/nasa/assets/images/nasa-logo.svg"> type:node]]] type:subitems]] map[node:map[boundingRect:map[bottom:15597 height:15323 left:0 right:412 top:275 width:412] lhId:page-6-MAIN nodeLabel:LIVE NASA’s Artemis II Crew Launches to the Moon Join us for continuing live c… path:1,HTML,1,BODY,8,MAIN selector:body.home > main#primary snippet:<main id="primary" class="site-main"> type:node] score:0.095658]]
headings: [map[key:node label:Element subItemsHeading:map[key:extra] valueType:node] map[granularity:0.001 key:score label:Layout shift score subItemsHeading:map[key:cause valueType:text] valueType:numeric]]
items: [map[node:map[type:text value:Total] score:0.24788] map[node:map[boundingRect:map[bottom:1047 height:261 left:24 right:388 top:786 width:364] lhId:page-0-P nodeLabel:Join us for continuing live coverage of Artemis II, the first crewed mission of… path:1,HTML,1,BODY,8,MAIN,0,ARTICLE,0,DIV,0,DIV,0,DIV,0,DIV,1,DIV,0,DIV,0,P selector:div.grid-container > div.hds-nasa-live-three-column-row > div.hds-vertical-align > p.margin-top-0 snippet:<p class="margin-top-0"> type:node] score:0.12394] map[node:map[boundingRect:map[bottom:1047 height:261 left:24 right:388 top:786 width:364] lhId:page-0-P nodeLabel:Join us for continuing live coverage of Artemis II, the first crewed mission of… path:1,HTML,1,BODY,8,MAIN,0,ARTICLE,0,DIV,0,DIV,0,DIV,0,DIV,1,DIV,0,DIV,0,P selector:div.grid-container > div.hds-nasa-live-three-column-row > div.hds-vertical-align > p.margin-top-0 snippet:<p class="margin-top-0"> type:node] score:0.12394]]

A forced reflow occurs when JavaScript queries geometric properties (such as offsetWidth) after styles have been invalidated by a change to the DOM state. This can result in poor performance. Learn more about forced reflows and possible mitigations.

headings: [map[key:source label:Top function call valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:31.685 source:map[column:27323 line:2 type:source-location url:https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVmDSvm+81tdeTCTJRPWKxsc25Yr5/1sBBhlgW9hcyHHwGxW88JVEUtTojt4pAgVfPUzoAGYFLBzJKNZq8J+xIqrck7/zjAQ2MjyS9o2WGjKakKQA1uufd0rn1uBo3bhuftz5wvg== urlProvider:network]]]
headings: [map[key:source label:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:106.179 source:map[type:text value:[unattributed]]] map[reflowTime:22.08 source:map[column:49615 line:1 type:source-location url:https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVmDSvm+81tdeTCTJRPWKxsc25Yr5/1sBBhlgW9hcyHHwGxW88JVEUtTojt4pAgVfPUzoAGYFLBzJKNZq8J+xIqrck7/zjAQ2MjyS9o2WGjKakKQA1uufd0rn1uBo3bhuftz5wvg== urlProvider:network]] map[reflowTime:4.359 source:map[column:50335 line:1 type:source-location url:https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVmDSvm+81tdeTCTJRPWKxsc25Yr5/1sBBhlgW9hcyHHwGxW88JVEUtTojt4pAgVfPUzoAGYFLBzJKNZq8J+xIqrck7/zjAQ2MjyS9o2WGjKakKQA1uufd0rn1uBo3bhuftz5wvg== urlProvider:network]] map[reflowTime:0.393 source:map[column:50393 line:1 type:source-location url:https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVmDSvm+81tdeTCTJRPWKxsc25Yr5/1sBBhlgW9hcyHHwGxW88JVEUtTojt4pAgVfPUzoAGYFLBzJKNZq8J+xIqrck7/zjAQ2MjyS9o2WGjKakKQA1uufd0rn1uBo3bhuftz5wvg== urlProvider:network]] map[reflowTime:0.329 source:map[column:50457 line:1 type:source-location url:https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVmDSvm+81tdeTCTJRPWKxsc25Yr5/1sBBhlgW9hcyHHwGxW88JVEUtTojt4pAgVfPUzoAGYFLBzJKNZq8J+xIqrck7/zjAQ2MjyS9o2WGjKakKQA1uufd0rn1uBo3bhuftz5wvg== urlProvider:network]] map[reflowTime:4.092 source:map[column:49637 line:1 type:source-location url:https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVmDSvm+81tdeTCTJRPWKxsc25Yr5/1sBBhlgW9hcyHHwGxW88JVEUtTojt4pAgVfPUzoAGYFLBzJKNZq8J+xIqrck7/zjAQ2MjyS9o2WGjKakKQA1uufd0rn1uBo3bhuftz5wvg== urlProvider:network]] map[reflowTime:0.432 source:map[column:51395 line:1 type:source-location url:https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVmDSvm+81tdeTCTJRPWKxsc25Yr5/1sBBhlgW9hcyHHwGxW88JVEUtTojt4pAgVfPUzoAGYFLBzJKNZq8J+xIqrck7/zjAQ2MjyS9o2WGjKakKQA1uufd0rn1uBo3bhuftz5wvg== urlProvider:network]] map[reflowTime:0.323 source:map[column:33 line:0 type:source-location url: urlProvider:network]] map[reflowTime:0.153 source:map[column:55 line:806 type:source-location url:https://www.googletagmanager.com/gtag/js?id=G-82GWVTTXCZ&cx=c&gtm=4e6411 urlProvider:network]]]

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

description: [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints help the browser establish a connection earlier in the page load, saving time when the first request for that origin is made. The following are the origins that the page preconnected to.
title: Preconnected origins
description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.
title: Preconnect candidates
value: No additional origins are good candidates for preconnecting

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

RequestCache TTLTransfer Size
/dynamicimage/assets/science/missions/punch/NFI-CME.png?w...43200.0 s2.0 MiB
/image/Artemis II at the pad sunsetting jet in background...300.0 s177.4 KiB
/image/art002e008486/art002e008486~large.jpg?w=768&h=576&...300.0 s176.7 KiB
/dynamicimage/assets/science/esd/eo/images/iotd/2026/bare...43200.0 s203.5 KiB
assets.science.nasa.gov/dynamicimage/assets/science/psd/ares/jsc2026e006229.jpg43200.0 s202.5 KiB
/dynamicimage/assets/science/missions/hubble/releases/202...43200.0 s187.7 KiB
/dynamicimage/assets/science/hpd/space-weather/SDO_02-04-...43200.0 s169.0 KiB
/dynamicimage/assets/science/psd/ares/jsc2026e006229.jpg?...43200.0 s134.2 KiB
/dynamicimage/assets/science/esd/eo/images/iotd/2026/fire...43200.0 s118.1 KiB
/image/iss074e0325229/iss074e0325229~large.jpg?w=768&h=51...300.0 s57.3 KiB
/dynamicimage/assets/science/esd/eo/images/iotd/2026/marc...43200.0 s101.2 KiB
/dynamicimage/assets/science/missions/xrism/News/2026/m82...43200.0 s74.4 KiB
i.ytimg.com/vi/m3kR2KK8TEs/sddefault.jpg?v=69a88d067200.0 s49.5 KiB
/dynamicimage/assets/science/missions/webb/science/2026/0...43200.0 s40.9 KiB
/dynamicimage/assets/science/esd/eo/images/iotd/2026/réu...43200.0 s38.7 KiB
/dynamicimage/assets/science/cds/citizen-science/projects...43200.0 s34.5 KiB
/Universal-Federated-Analytics-Min.js?agency=NASA&pga4=G-...0.0 ms9.4 KiB
dap.digitalgov.gov/web-vitals/dist/web-vitals.attribution.iife.js0.0 ms4.5 KiB
/eIf5fNPcIcj9ig-wZBeq4stFy1lgjWTW1nLT5dYlFkHZprZ03QBiMcbp...86400.0 s10.6 KiB
/eIf5fNPcIcj9ig-wZBeq4stFy1lgjWTW1nLT5dYlFkHZprZ03QBiMcbp...86400.0 s5.6 KiB
i.ytimg.com/vi/Azfx_wRROZM/default.jpg300.0 s1.9 KiB
static.doubleclick.net/instream/ad_status.js900.0 s495 B
/px/?rand=1775488085613&plid=e86b2ae9-2028-4a49-ab95-f639...0.0 ms229 B
/px/?rand=1775488087195&plid=e86b2ae9-2028-4a49-ab95-f639...0.0 ms229 B
static.doubleclick.net/instream/ad_status.js900.0 s0 B

Consider setting font-display to swap or optional to ensure text is consistently visible. swap can be further optimized to mitigate layout shifts with font metric overrides.

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

URLResource SizeEst Savings
div.padding-right-3 > div.hds-cover-wrapper > figure.hds-media-background > img div.padding-right-3 > div.hds-cover-wrapper > figure.hds-media-background > img
assets.science.nasa.gov/dynamicimage/assets/science/psd/ares/jsc2026e006229.jpg201.7 KiB200.3 KiB
div.padding-right-3 > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail div.padding-right-3 > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail
/image/Artemis II at the pad sunsetting jet in background...176.6 KiB175.6 KiB
a.tablet:grid-col > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-large a.tablet:grid-col > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-large
/image/art002e008486/art002e008486~large.jpg?w=768&h=576&...175.9 KiB154.1 KiB
a.tablet:grid-col > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-large a.tablet:grid-col > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-large
/wp-content/uploads/2026/04/screenshot-2026-04-05-at-10-0...104.7 KiB93.4 KiB
a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail
www.nasa.gov/wp-content/uploads/2026/03/prime-video-icon.png47.6 KiB47.5 KiB
a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail
www.nasa.gov/wp-content/uploads/2026/03/netflix-symbol.png31.7 KiB31.6 KiB
a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail
www.nasa.gov/wp-content/uploads/2026/01/peacock-icon-sq.png30.2 KiB29.1 KiB
a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail
www.nasa.gov/wp-content/uploads/2026/01/logo-white-sq.png23.3 KiB23.3 KiB
a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail
www.nasa.gov/wp-content/uploads/2026/01/facebook-logo-primary-sq.png14.0 KiB14.0 KiB
article#post-128943 > div.width-full > figure.hds-media-background > img.attachment-2048x2048 article#post-128943 > div.width-full > figure.hds-media-background > img.attachment-2048x2048
/wp-content/uploads/2023/02/artemisiicrewposterorig-notex...57.7 KiB13.9 KiB
div.padding-right-3 > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail div.padding-right-3 > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail
/wp-content/uploads/2026/01/53206112789-e5e932c583-o.jpg?...8.0 KiB4.4 KiB

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

TTI

These are the largest layout shifts observed on the page. Each table item represents a single layout shift, and shows the element that shifted the most. Below each item are possible root causes that led to the layout shift. Some of these layout shifts may not be included in the CLS metric value due to windowing. Learn how to improve CLS

ElementLayout shift score
Join us for continuing live coverage of Artemis II, the first crewed mission of… div.hds-nasa-live-main > div.grid-container > div.hds-nasa-live-three-column-row > div.hds-vertical-align
0.173
Join us for continuing live coverage of Artemis II, the first crewed mission of… div.grid-container > div.hds-nasa-live-three-column-row > div.hds-vertical-align > p.margin-top-0
0.124
Join us for continuing live coverage of Artemis II, the first crewed mission of… div.grid-container > div.hds-nasa-live-three-column-row > div.hds-vertical-align > p.margin-top-0
0.124
LIVE NASA’s Artemis II Crew Launches to the Moon Join us for continuing live c… body.home > main#primary
0.096

The maximum potential First Input Delay that your users could experience is the duration of the longest task. Learn more about the Maximum Potential First Input Delay metric.

Diagnostics

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.

Estimated savings: 300 ms 39.0 KiB

Consider reducing the time spent parsing, compiling, and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to reduce Javascript execution time.

Consider reducing the time spent parsing, compiling and executing JS. You may find delivering smaller JS payloads helps with this. Learn how to minimize main-thread work

CategoryTime Spent
Other1.9 s
Script Evaluation1.8 s
Style & Layout1.3 s
Rendering1.2 s
Parse HTML & CSS286 ms
Script Parsing & Compilation283 ms

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

More information about the performance of your application. These numbers don't directly affect the Performance score.

Document request latency
Optimize DOM size
LCP breakdown
Modern HTTP
Optimize viewport for mobile
Minify CSS
Minify JavaScript
User Timing marks and measures 16 user timings
Avoid long main-thread tasks 19 long tasks found
Avoid non-composited animations 6 animated elements found
Image elements have explicit `width` and `height`
Page didn't prevent back/forward cache restoration
Network Requests
Network Round Trip Times 70 ms
Server Backend Latencies 110 ms
Tasks
Diagnostics
Metrics
Screenshot Thumbnails
Final Screenshot
Script Treemap Data
Resources Summary
Avoid multiple page redirects
Initial server response time was short Root document took 0 ms
INP breakdown
LCP request discovery
89

Accessibility

These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.

Names and labels

When a button doesn't have an accessible name, screen readers announce it as "button", making it unusable for users who rely on screen readers. Learn how to make buttons more accessible.

Failing Elements
header.hds-nasa-header > div.usa-nav-container > div.grid-col > button#global-navigation-trigger--mobile header.hds-nasa-header > div.usa-nav-container > div.grid-col > button#global-navigation-trigger--mobile
header.hds-nasa-header > div.usa-nav-container > div.grid-col > button.hds-search-panel-mobile-trigger header.hds-nasa-header > div.usa-nav-container > div.grid-col > button.hds-search-panel-mobile-trigger

Link text (and alternate text for images, when used as links) that is discernible, unique, and focusable improves the navigation experience for screen reader users. Learn how to make links accessible.

Failing Elements
div.slick-track > div.hds-meet-the-card > div.hds-meet-the-inner > a.hds-meet-the-image div.slick-track > div.hds-meet-the-card > div.hds-meet-the-inner > a.hds-meet-the-image
div.grid-row > div.grid-col-12 > div.hds-image-download-wrapper > a.hds-image-download-link div.grid-row > div.grid-col-12 > div.hds-image-download-wrapper > a.hds-image-download-link

These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.

Contrast

Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.

Failing Elements
04 div.countdown-item > div.countdown-item-inner > p
days div.countdown-item > div.countdown-item-inner > span.label
16 div.countdown-item > div.countdown-item-inner > p
hrs div.countdown-item > div.countdown-item-inner > span.label
33 div.countdown-item > div.countdown-item-inner > p
mins div.countdown-item > div.countdown-item-inner > span.label
11 div.countdown-item > div.countdown-item-inner > p
secs div.countdown-item > div.countdown-item-inner > span.label
LIVE div.hds-nasa-live-main > div.grid-container > div.w-full > div.hds-live-tag

These are opportunities to improve the legibility of your content.

Visible text labels that do not match the accessible name can result in a confusing experience for screen reader users. Learn more about accessible names.

Failing Elements
Artemis II Flight Day 6: Crew Ready for Lunar Flyby ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Artemis II Flight Day 5: Correction Burn Complete  ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Artemis II Flight Day 5: Crew Demos Suits, Readies for Lunar Flyby  ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Artemis II Flight Day 5: Crew Starts Day with Suit Demo  ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Artemis II Flight Day 4: Crew Completes Manual Piloting Demonstration  ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Artemis II Flight Day 4: Deep-Space Flying, Lunar Flyby Prep ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Artemis II Flight Day 3: Crew Prepares Cabin for Lunar Flyby ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Artemis II Flight Day 3: Outbound Trajectory Correction Burn Update ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Artemis II Flight Day 3: Crew Prepares for First Correction Burn, Readies to Re… ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Artemis II Flight Day 2: Orion Completes TLI Burn, Crew Begins Journey to the M… ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Interactive controls are keyboard focusable
Interactive elements indicate their purpose and state
The page has a logical tab order
Visual order on the page follows DOM order
User focus is not accidentally trapped in a region
The user's focus is directed to new content added to the page
HTML5 landmark elements are used to improve navigation
Offscreen content is hidden from assistive technology
Custom controls have associated labels
Custom controls have ARIA roles
`[aria-*]` attributes match their roles
`[aria-hidden="true"]` is not present on the document `<body>`
`[role]`s have all required `[aria-*]` attributes
`[role]` values are valid
`[aria-*]` attributes have valid values
`[aria-*]` attributes are valid and not misspelled
Image elements have `[alt]` attributes
`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
`button`, `link`, and `menuitem` elements have accessible names
ARIA attributes are used as specified for the element's role
`[aria-hidden="true"]` elements do not contain focusable descendents
ARIA input fields have accessible names
Elements use only permitted ARIA attributes
Document has a `<title>` element
`<frame>` or `<iframe>` elements have a title
`<html>` element has a `[lang]` attribute
`<html>` element has a valid value for its `[lang]` attribute
Links are distinguishable without relying on color.
Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements
No element has a `[tabindex]` value greater than 0
Touch targets have sufficient size and spacing.
Heading elements appear in a sequentially-descending order
Document has a main landmark.
Deprecated ARIA roles were not used
Identical links have the same purpose.
`[accesskey]` values are unique
Elements with `role="dialog"` or `role="alertdialog"` have accessible names.
ARIA `meter` elements have accessible names
ARIA `progressbar` elements have accessible names
Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.
`[role]`s are contained by their required parent element
Elements with the `role=text` attribute do not have focusable descendents.
ARIA toggle fields have accessible names
ARIA `tooltip` elements have accessible names
ARIA `treeitem` elements have accessible names
The page contains a heading, skip link, or landmark region
`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.
Definition list items are wrapped in `<dl>` elements
ARIA IDs are unique
No form fields have multiple labels
`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.
Input buttons have discernible text.
`<input type="image">` elements have `[alt]` text
Form elements have associated labels
The document does not use `<meta http-equiv="refresh">`
`<object>` elements have alternate text
Select elements have associated label elements.
Skip links are focusable.
Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.
`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.
`[lang]` attributes have a valid value
`<video>` elements contain a `<track>` element with `[kind="captions"]`
Tables have different content in the summary attribute and `<caption>`.
All heading elements contain content.
Uses ARIA roles only on compatible elements
Image elements do not have `[alt]` attributes that are redundant text.
Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.
`<td>` elements in a large `<table>` have one or more table headers.
96

Best Practices

General

Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns. Learn more about this errors in console diagnostic audit

SourceDescription
www.nasa.gov/ line 1856, col 8
TypeError: Cannot read properties of undefined (reading 'setLocaleData') at https://www.nasa.gov/:1857:9
Uses HTTPS
Avoids deprecated APIs
Avoids third-party cookies
Allows users to paste into input fields
Avoids requesting the geolocation permission on page load
Avoids requesting the notification permission on page load
Displays images with correct aspect ratio
Serves images with appropriate resolution
Page has the HTML doctype
Properly defines charset
No issues in the `Issues` panel in Chrome Devtools
Ensure CSP is effective against XSS attacks
Ensure proper origin isolation with COOP
Mitigate DOM-based XSS with Trusted Types
Detected JavaScript libraries
Page has valid source maps
Redirects HTTP traffic to HTTPS
Use a strong HSTS policy
Mitigate clickjacking with XFO or CSP
100

SEO

These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.

Structured data is valid
Page isn’t blocked from indexing
Document has a `<title>` element
Document has a meta description
Page has successful HTTP status code
Links have descriptive text
Links are crawlable
robots.txt is valid
Image elements have `[alt]` attributes
Document has a valid `hreflang`
Document has a valid `rel=canonical`

Lighthouse Scores

Industry-standard audits powered by Google Lighthouse. — Desktop

63
Performance Overall performance score (0–100) based on Core Web Vitals and other metrics. 90+ is good.
93
Accessibility Measures how accessible the page is for users with disabilities. Checks color contrast, ARIA labels, and semantic HTML.
96
Best Practices Checks for modern web development best practices including HTTPS, no console errors, and secure JavaScript.
100
SEO Measures basic SEO optimizations: meta tags, crawlability, link text, and mobile friendliness.

Core Web Vitals

Key metrics that affect user experience. — Desktop

First Contentful Paint First Contentful Paint — how long until the browser renders the first piece of content. Under 1.8s is good.

539 ms

Largest Contentful Paint Largest Contentful Paint — how long until the largest visible element loads. Under 2.5s is good.

2.97 s

Total Blocking Time Total Blocking Time — total time the main thread was blocked, preventing user input. Under 200ms is good.

52 ms

Cumulative Layout Shift Cumulative Layout Shift — measures visual stability. How much the page layout shifts during loading. Under 0.1 is good.

0.429

Speed Index Speed Index — how quickly content is visually displayed during load. Under 3.4s is good.

1.30 s

Time to Interactive Time to Interactive — how long until the page is fully interactive and responds to user input. Under 3.8s is good.

3.72 s

Detailed Report

Audit breakdown by category with detailed findings.

63

Performance

Insights

Remove large, duplicate JavaScript modules from bundles to reduce unnecessary bytes consumed by network activity.

Polyfills and transforms enable older browsers to use new JavaScript features. However, many aren't necessary for modern browsers. Consider modifying your JavaScript build process to not transpile Baseline features, unless you know you must support older browsers. Learn why most sites can deploy ES6+ code without transpiling

3rd party code can significantly impact load performance. Reduce and defer loading of 3rd party code to prioritize your page's content.

Layout shifts occur when elements move absent any user interaction. Investigate the causes of layout shifts, such as elements being added, removed, or their fonts changing as the page loads.

headings: [map[key:node label:Element subItemsHeading:map[key:extra] valueType:node] map[granularity:0.001 key:score label:Layout shift score subItemsHeading:map[key:cause valueType:text] valueType:numeric]]
items: [map[node:map[type:text value:Total] score:0.42938699999999996] map[node:map[boundingRect:map[bottom:7708 height:7431 left:0 right:1335 top:277 width:1335] lhId:page-12-MAIN nodeLabel:LIVE NASA’s Artemis II Crew Launches to the Moon Join us for continuing live c… path:1,HTML,1,BODY,8,MAIN selector:body.home > main#primary snippet:<main id="primary" class="site-main"> type:node] score:0.111145] map[node:map[boundingRect:map[bottom:0 height:0 left:0 right:0 top:0 width:0] lhId:page-16-path nodeLabel:svg.square-2 > g > g > path path:1,HTML,1,BODY,6,DIV,0,DIV,0,DIV,1,DIV,1,DIV,0,A,1,DIV,2,DIV,0,SPAN,0,svg,0,g,0,g,0,path selector:svg.square-2 > g > g > path snippet:<path d="M8,0C3.5,0-0.1,3.7,0,8.2C0.1,12.5,3.6,16,8,16c4.4,0,8-3.6,8-8C16,3.5,12.4,…"> type:node] score:0.103266] map[node:map[boundingRect:map[bottom:7817 height:54 left:24 right:88 top:7764 width:64] lhId:page-17-IMG nodeLabel:NASA Logo path:1,HTML,1,BODY,10,FOOTER,0,DIV,0,DIV,0,IMG selector:footer.usa-footer > div.usa-footer__primary-section > div.grid-container > img.width-8 snippet:<img fetchpriority="low" width="63.99" height="53.94" class="width-8 margin-bottom-2" alt="NASA Logo" src="https://www.nasa.gov/wp-content/themes/nasa/assets/images/nasa-logo.svg" srcset="https://www.nasa.gov/wp-content/themes/nasa/assets/images/nasa-logo.svg"> type:node] score:0.103266] map[node:map[boundingRect:map[bottom:7817 height:54 left:24 right:88 top:7764 width:64] lhId:page-17-IMG nodeLabel:NASA Logo path:1,HTML,1,BODY,10,FOOTER,0,DIV,0,DIV,0,IMG selector:footer.usa-footer > div.usa-footer__primary-section > div.grid-container > img.width-8 snippet:<img fetchpriority="low" width="63.99" height="53.94" class="width-8 margin-bottom-2" alt="NASA Logo" src="https://www.nasa.gov/wp-content/themes/nasa/assets/images/nasa-logo.svg" srcset="https://www.nasa.gov/wp-content/themes/nasa/assets/images/nasa-logo.svg"> type:node] score:0.103266] map[node:map[boundingRect:map[bottom:938 height:64 left:1029 right:1311 top:874 width:282] lhId:page-15-::after nodeLabel:div.grid-col-12 > div.hds-live-updates > div.hds-live-updates-items-container > ::after path:1,HTML,1,BODY,8,MAIN,0,ARTICLE,0,DIV,0,DIV,0,DIV,0,DIV,1,DIV,2,DIV,0,DIV,1,DIV,0,::after selector:div.grid-col-12 > div.hds-live-updates > div.hds-live-updates-items-container > ::after snippet:<::after> type:node] score:0.008428]]

A forced reflow occurs when JavaScript queries geometric properties (such as offsetWidth) after styles have been invalidated by a change to the DOM state. This can result in poor performance. Learn more about forced reflows and possible mitigations.

headings: [map[key:source label:Top function call valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:28.999 source:map[column:27323 line:2 type:source-location url:https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVmDSvm+81tdeTCTJRPWKxsc25Yr5/1sBBhlgW9hcyHHwGxW88JVEUtTojt4pAgVfPUzoAGYFLBzJKNZq8J+xIqrck7/zjAQ2MjyS9o2WGjKakKQA1uufd0rn1uBo3bhuftz5wvg== urlProvider:network]]]
headings: [map[key:source label:Source valueType:source-location] map[granularity:1 key:reflowTime label:Total reflow time valueType:ms]]
items: [map[reflowTime:121.903 source:map[type:text value:[unattributed]]] map[reflowTime:13.919 source:map[column:49615 line:1 type:source-location url:https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVmDSvm+81tdeTCTJRPWKxsc25Yr5/1sBBhlgW9hcyHHwGxW88JVEUtTojt4pAgVfPUzoAGYFLBzJKNZq8J+xIqrck7/zjAQ2MjyS9o2WGjKakKQA1uufd0rn1uBo3bhuftz5wvg== urlProvider:network]] map[reflowTime:8.485 source:map[column:50335 line:1 type:source-location url:https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVmDSvm+81tdeTCTJRPWKxsc25Yr5/1sBBhlgW9hcyHHwGxW88JVEUtTojt4pAgVfPUzoAGYFLBzJKNZq8J+xIqrck7/zjAQ2MjyS9o2WGjKakKQA1uufd0rn1uBo3bhuftz5wvg== urlProvider:network]] map[reflowTime:0.701 source:map[column:50393 line:1 type:source-location url:https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVmDSvm+81tdeTCTJRPWKxsc25Yr5/1sBBhlgW9hcyHHwGxW88JVEUtTojt4pAgVfPUzoAGYFLBzJKNZq8J+xIqrck7/zjAQ2MjyS9o2WGjKakKQA1uufd0rn1uBo3bhuftz5wvg== urlProvider:network]] map[reflowTime:0.56 source:map[column:50457 line:1 type:source-location url:https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVmDSvm+81tdeTCTJRPWKxsc25Yr5/1sBBhlgW9hcyHHwGxW88JVEUtTojt4pAgVfPUzoAGYFLBzJKNZq8J+xIqrck7/zjAQ2MjyS9o2WGjKakKQA1uufd0rn1uBo3bhuftz5wvg== urlProvider:network]] map[reflowTime:4.214 source:map[column:49637 line:1 type:source-location url:https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVmDSvm+81tdeTCTJRPWKxsc25Yr5/1sBBhlgW9hcyHHwGxW88JVEUtTojt4pAgVfPUzoAGYFLBzJKNZq8J+xIqrck7/zjAQ2MjyS9o2WGjKakKQA1uufd0rn1uBo3bhuftz5wvg== urlProvider:network]] map[reflowTime:1.12 source:map[column:51395 line:1 type:source-location url:https://www.nasa.gov/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVmDSvm+81tdeTCTJRPWKxsc25Yr5/1sBBhlgW9hcyHHwGxW88JVEUtTojt4pAgVfPUzoAGYFLBzJKNZq8J+xIqrck7/zjAQ2MjyS9o2WGjKakKQA1uufd0rn1uBo3bhuftz5wvg== urlProvider:network]] map[reflowTime:2.626 source:map[column:33 line:0 type:source-location url: urlProvider:network]] map[reflowTime:0.269 source:map[column:376 line:760 type:source-location url:https://www.googletagmanager.com/gtag/js?id=G-82GWVTTXCZ&cx=c&gtm=4e6411 urlProvider:network]]]

Reducing the download time of images can improve the perceived load time of the page and LCP. Learn more about optimizing image size

URLResource SizeEst Savings
div.padding-right-3 > div.hds-cover-wrapper > figure.hds-media-background > img div.padding-right-3 > div.hds-cover-wrapper > figure.hds-media-background > img
assets.science.nasa.gov/dynamicimage/assets/science/psd/ares/jsc2026e006229.jpg201.7 KiB200.3 KiB
div.padding-right-3 > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail div.padding-right-3 > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail
/image/Artemis II at the pad sunsetting jet in background...176.6 KiB175.6 KiB
a.tablet:grid-col > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-large a.tablet:grid-col > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-large
/image/art002e008486/art002e008486~large.jpg?w=1536&h=115...175.9 KiB156.2 KiB
a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail
www.nasa.gov/wp-content/uploads/2026/03/prime-video-icon.png47.6 KiB47.5 KiB
a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail
www.nasa.gov/wp-content/uploads/2026/03/netflix-symbol.png31.7 KiB31.6 KiB
a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail
www.nasa.gov/wp-content/uploads/2026/01/peacock-icon-sq.png30.2 KiB29.1 KiB
a.tablet:grid-col > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-large a.tablet:grid-col > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-large
/wp-content/uploads/2026/04/screenshot-2026-04-05-at-10-0...31.2 KiB23.7 KiB
a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail
www.nasa.gov/wp-content/uploads/2026/01/logo-white-sq.png23.3 KiB23.3 KiB
a.tablet:grid-col > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-large a.tablet:grid-col > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-large
/wp-content/uploads/2026/03/2026-02-03-screenshot-258-256...21.5 KiB18.5 KiB
a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail a.hds-meet-the-image > div.hds-cover-wrapper > figure.hds-media-background > img.attachment-thumbnail
www.nasa.gov/wp-content/uploads/2026/01/facebook-logo-primary-sq.png14.0 KiB14.0 KiB

Avoid chaining critical requests by reducing the length of chains, reducing the download size of resources, or deferring the download of unnecessary resources to improve page load.

description: [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints help the browser establish a connection earlier in the page load, saving time when the first request for that origin is made. The following are the origins that the page preconnected to.
title: Preconnected origins
description: Add [preconnect](https://developer.chrome.com/docs/lighthouse/performance/uses-rel-preconnect/) hints to your most important origins, but try to use no more than 4.
title: Preconnect candidates

Requests are blocking the page's initial render, which may delay LCP. Deferring or inlining can move these network requests out of the critical path.

A long cache lifetime can speed up repeat visits to your page. Learn more about caching.

RequestCache TTLTransfer Size
/dynamicimage/assets/science/missions/punch/NFI-CME.png?w...43200.0 s2.0 MiB
/image/Artemis II at the pad sunsetting jet in background...300.0 s177.4 KiB
/image/art002e008486/art002e008486~large.jpg?w=1536&h=115...300.0 s176.7 KiB
i.ytimg.com/vi/m3kR2KK8TEs/maxresdefault.jpg?v=69a88d067200.0 s150.6 KiB
/dynamicimage/assets/science/esd/eo/images/iotd/2026/bare...43200.0 s203.5 KiB
assets.science.nasa.gov/dynamicimage/assets/science/psd/ares/jsc2026e006229.jpg43200.0 s202.5 KiB
/dynamicimage/assets/science/missions/hubble/releases/202...43200.0 s187.7 KiB
/dynamicimage/assets/science/hpd/space-weather/SDO_02-04-...43200.0 s169.0 KiB
/dynamicimage/assets/science/psd/ares/jsc2026e006229.jpg?...43200.0 s134.2 KiB
/dynamicimage/assets/science/esd/eo/images/iotd/2026/fire...43200.0 s118.1 KiB
/image/iss074e0325229/iss074e0325229~large.jpg?w=1536&h=1...300.0 s57.3 KiB
/dynamicimage/assets/science/esd/eo/images/iotd/2026/marc...43200.0 s101.2 KiB
/dynamicimage/assets/science/missions/xrism/News/2026/m82...43200.0 s74.4 KiB
/dynamicimage/assets/science/missions/webb/science/2026/0...43200.0 s40.9 KiB
/dynamicimage/assets/science/esd/eo/images/iotd/2026/réu...43200.0 s38.7 KiB
/dynamicimage/assets/science/cds/citizen-science/projects...43200.0 s34.5 KiB
/Universal-Federated-Analytics-Min.js?agency=NASA&pga4=G-...0.0 ms9.4 KiB
dap.digitalgov.gov/web-vitals/dist/web-vitals.attribution.iife.js0.0 ms4.5 KiB
/eIf5fNPcIcj9ig-wZBeq4stFy1lgjWTW1nLT5dYlFkHZprZ03QBiMcbp...86400.0 s10.6 KiB
/eIf5fNPcIcj9ig-wZBeq4stFy1lgjWTW1nLT5dYlFkHZprZ03QBiMcbp...86400.0 s5.6 KiB
i.ytimg.com/vi/6RwfNBtepa4/default.jpg?v=69c580377200.0 s2.2 KiB
static.doubleclick.net/instream/ad_status.js900.0 s495 B
/px/?rand=1775488106458&plid=e72faf0f-98fe-479e-81f7-c62b...0.0 ms229 B
/px/?rand=1775488108209&plid=e72faf0f-98fe-479e-81f7-c62b...0.0 ms229 B
static.doubleclick.net/instream/ad_status.js900.0 s0 B

These insights are also available in the Chrome DevTools Performance Panel - record a trace to view more detailed information.

These are the largest layout shifts observed on the page. Each table item represents a single layout shift, and shows the element that shifted the most. Below each item are possible root causes that led to the layout shift. Some of these layout shifts may not be included in the CLS metric value due to windowing. Learn how to improve CLS

ElementLayout shift score
LIVE NASA’s Artemis II Crew Launches to the Moon Join us for continuing live c… body.home > main#primary
0.111
svg.square-2 > g > g > path svg.square-2 > g > g > path
0.103
NASA Logo footer.usa-footer > div.usa-footer__primary-section > div.grid-container > img.width-8
0.103
NASA Logo footer.usa-footer > div.usa-footer__primary-section > div.grid-container > img.width-8
0.103
div.grid-col-12 > div.hds-live-updates > div.hds-live-updates-items-container > ::after div.grid-col-12 > div.hds-live-updates > div.hds-live-updates-items-container > ::after
0.008
Live Mission Updates div.grid-col-12 > div.hds-live-updates > div.hds-live-updates-heading > h3.heading-14
0.000

Time to Interactive is the amount of time it takes for the page to become fully interactive. Learn more about the Time to Interactive metric.

TTI

Diagnostics

Reduce unused rules from stylesheets and defer CSS not used for above-the-fold content to decrease bytes consumed by network activity. Learn how to reduce unused CSS.

Estimated savings: 10 ms 38.0 KiB

Reduce unused JavaScript and defer loading scripts until they are required to decrease bytes consumed by network activity. Learn how to reduce unused JavaScript.

More information about the performance of your application. These numbers don't directly affect the Performance score.

Max Potential First Input Delay 120 ms
Document request latency
Optimize DOM size
LCP breakdown
Modern HTTP
Optimize viewport for mobile
Minify CSS
Minify JavaScript
User Timing marks and measures 16 user timings
JavaScript execution time 0.5 s
Minimizes main-thread work 1.8 s
Avoid long main-thread tasks 5 long tasks found
Avoid non-composited animations 6 animated elements found
Image elements have explicit `width` and `height`
Page didn't prevent back/forward cache restoration
Network Requests
Network Round Trip Times 70 ms
Server Backend Latencies 70 ms
Tasks
Diagnostics
Metrics
Screenshot Thumbnails
Final Screenshot
Script Treemap Data
Resources Summary
Avoid multiple page redirects
Initial server response time was short Root document took 0 ms
INP breakdown
LCP request discovery
93

Accessibility

These checks highlight opportunities to improve the accessibility of your web app. Automatic detection can only detect a subset of issues and does not guarantee the accessibility of your web app, so manual testing is also encouraged.

Contrast

Low-contrast text is difficult or impossible for many users to read. Learn how to provide sufficient color contrast.

Failing Elements
04 div.countdown-item > div.countdown-item-inner > p
days div.countdown-item > div.countdown-item-inner > span.label
16 div.countdown-item > div.countdown-item-inner > p
hrs div.countdown-item > div.countdown-item-inner > span.label
33 div.countdown-item > div.countdown-item-inner > p
mins div.countdown-item > div.countdown-item-inner > span.label
32 div.countdown-item > div.countdown-item-inner > p
secs div.countdown-item > div.countdown-item-inner > span.label
LIVE div.hds-nasa-live-main > div.grid-container > div.w-full > div.hds-live-tag

These are opportunities to improve the legibility of your content.

Names and labels

Link text (and alternate text for images, when used as links) that is discernible, unique, and focusable improves the navigation experience for screen reader users. Learn how to make links accessible.

Failing Elements
div.slick-track > div.hds-meet-the-card > div.hds-meet-the-inner > a.hds-meet-the-image div.slick-track > div.hds-meet-the-card > div.hds-meet-the-inner > a.hds-meet-the-image
div.slick-track > div.hds-meet-the-card > div.hds-meet-the-inner > a.hds-meet-the-image div.slick-track > div.hds-meet-the-card > div.hds-meet-the-inner > a.hds-meet-the-image
div.slick-track > div.hds-meet-the-card > div.hds-meet-the-inner > a.hds-meet-the-image div.slick-track > div.hds-meet-the-card > div.hds-meet-the-inner > a.hds-meet-the-image
div.slick-track > div.hds-meet-the-card > div.hds-meet-the-inner > a.hds-meet-the-image div.slick-track > div.hds-meet-the-card > div.hds-meet-the-inner > a.hds-meet-the-image
div.grid-row > div.grid-col-12 > div.hds-image-download-wrapper > a.hds-image-download-link div.grid-row > div.grid-col-12 > div.hds-image-download-wrapper > a.hds-image-download-link

These are opportunities to improve the semantics of the controls in your application. This may enhance the experience for users of assistive technology, like a screen reader.

Visible text labels that do not match the accessible name can result in a confusing experience for screen reader users. Learn more about accessible names.

Failing Elements
Artemis II Flight Day 6: Crew Ready for Lunar Flyby ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Artemis II Flight Day 5: Correction Burn Complete  ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Artemis II Flight Day 5: Crew Demos Suits, Readies for Lunar Flyby  ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Artemis II Flight Day 5: Crew Starts Day with Suit Demo  ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Artemis II Flight Day 4: Crew Completes Manual Piloting Demonstration  ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Artemis II Flight Day 4: Deep-Space Flying, Lunar Flyby Prep ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Artemis II Flight Day 3: Crew Prepares Cabin for Lunar Flyby ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Artemis II Flight Day 3: Outbound Trajectory Correction Burn Update ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Artemis II Flight Day 3: Crew Prepares for First Correction Burn, Readies to Re… ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Artemis II Flight Day 2: Orion Completes TLI Burn, Crew Begins Journey to the M… ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a
Interactive controls are keyboard focusable
Interactive elements indicate their purpose and state
The page has a logical tab order
Visual order on the page follows DOM order
User focus is not accidentally trapped in a region
The user's focus is directed to new content added to the page
HTML5 landmark elements are used to improve navigation
Offscreen content is hidden from assistive technology
Custom controls have associated labels
Custom controls have ARIA roles
`[aria-*]` attributes match their roles
`[aria-hidden="true"]` is not present on the document `<body>`
`[role]`s have all required `[aria-*]` attributes
`[role]` values are valid
`[aria-*]` attributes have valid values
`[aria-*]` attributes are valid and not misspelled
Buttons have an accessible name
Image elements have `[alt]` attributes
Form elements have associated labels
`[user-scalable="no"]` is not used in the `<meta name="viewport">` element and the `[maximum-scale]` attribute is not less than 5.
`button`, `link`, and `menuitem` elements have accessible names
ARIA attributes are used as specified for the element's role
`[aria-hidden="true"]` elements do not contain focusable descendents
ARIA input fields have accessible names
Elements use only permitted ARIA attributes
Document has a `<title>` element
`<frame>` or `<iframe>` elements have a title
`<html>` element has a `[lang]` attribute
`<html>` element has a valid value for its `[lang]` attribute
Lists contain only `<li>` elements and script supporting elements (`<script>` and `<template>`).
List items (`<li>`) are contained within `<ul>`, `<ol>` or `<menu>` parent elements
No element has a `[tabindex]` value greater than 0
Touch targets have sufficient size and spacing.
Heading elements appear in a sequentially-descending order
Document has a main landmark.
Deprecated ARIA roles were not used
Identical links have the same purpose.
`[accesskey]` values are unique
Elements with `role="dialog"` or `role="alertdialog"` have accessible names.
ARIA `meter` elements have accessible names
ARIA `progressbar` elements have accessible names
Elements with an ARIA `[role]` that require children to contain a specific `[role]` have all required children.
`[role]`s are contained by their required parent element
Elements with the `role=text` attribute do not have focusable descendents.
ARIA toggle fields have accessible names
ARIA `tooltip` elements have accessible names
ARIA `treeitem` elements have accessible names
The page contains a heading, skip link, or landmark region
`<dl>`'s contain only properly-ordered `<dt>` and `<dd>` groups, `<script>`, `<template>` or `<div>` elements.
Definition list items are wrapped in `<dl>` elements
ARIA IDs are unique
No form fields have multiple labels
`<html>` element has an `[xml:lang]` attribute with the same base language as the `[lang]` attribute.
Input buttons have discernible text.
`<input type="image">` elements have `[alt]` text
Links are distinguishable without relying on color.
The document does not use `<meta http-equiv="refresh">`
`<object>` elements have alternate text
Select elements have associated label elements.
Skip links are focusable.
Cells in a `<table>` element that use the `[headers]` attribute refer to table cells within the same table.
`<th>` elements and elements with `[role="columnheader"/"rowheader"]` have data cells they describe.
`[lang]` attributes have a valid value
`<video>` elements contain a `<track>` element with `[kind="captions"]`
Tables have different content in the summary attribute and `<caption>`.
All heading elements contain content.
Uses ARIA roles only on compatible elements
Image elements do not have `[alt]` attributes that are redundant text.
Tables use `<caption>` instead of cells with the `[colspan]` attribute to indicate a caption.
`<td>` elements in a large `<table>` have one or more table headers.
96

Best Practices

General

Errors logged to the console indicate unresolved problems. They can come from network request failures and other browser concerns. Learn more about this errors in console diagnostic audit

SourceDescription
www.nasa.gov/ line 1856, col 8
TypeError: Cannot read properties of undefined (reading 'setLocaleData') at https://www.nasa.gov/:1857:9
Uses HTTPS
Avoids deprecated APIs
Avoids third-party cookies
Allows users to paste into input fields
Avoids requesting the geolocation permission on page load
Avoids requesting the notification permission on page load
Displays images with correct aspect ratio
Serves images with appropriate resolution
Page has the HTML doctype
Properly defines charset
No issues in the `Issues` panel in Chrome Devtools
Ensure CSP is effective against XSS attacks
Ensure proper origin isolation with COOP
Mitigate DOM-based XSS with Trusted Types
Detected JavaScript libraries
Page has valid source maps
Redirects HTTP traffic to HTTPS
Use a strong HSTS policy
Mitigate clickjacking with XFO or CSP
100

SEO

These checks ensure that your page is following basic search engine optimization advice. There are many additional factors Lighthouse does not score here that may affect your search ranking, including performance on Core Web Vitals. Learn more about Google Search Essentials.

Structured data is valid
Page isn’t blocked from indexing
Document has a `<title>` element
Document has a meta description
Page has successful HTTP status code
Links have descriptive text
Links are crawlable
robots.txt is valid
Image elements have `[alt]` attributes
Document has a valid `hreflang`
Document has a valid `rel=canonical`

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