Lighthouse Mobile

· 0 checks — Mobile Lighthouse audit -- Performance, Accessibility, Best Practices, and SEO category breakdown.

SCORE

GRADE

FIX

REVIEW

PASS

INFO

Detailed Report

Audit breakdown by category with detailed findings.

Performance

Insights

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

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:0.252176] map[node:map[boundingRect:map[bottom:754 height:253 left:24 right:388 top:501 width:364] lhId:page-1-DIV nodeLabel:Live Views From Orion path:1,HTML,1,BODY,8,MAIN,0,ARTICLE,0,DIV,0,DIV,0,DIV,0,DIV,1,DIV,1,DIV selector:div.hds-nasa-live-main > div.grid-container > div.hds-nasa-live-three-column-row > div.grid-col-12 snippet:<div class="grid-col-12 desktop:grid-col-6 padding-0 margin-bottom-4 desktop:margin-bo…"> type:node] score:0.156518 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-15-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:15645 height:15370 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]]

items: [map[node:map[type:text value:Total] score:0.24788] map[node:map[boundingRect:map[bottom:1688 height:17 left:500 right:568 top:1672 width:68] lhId:page-8-H3 nodeLabel:YouTube path:1,HTML,1,BODY,8,MAIN,0,ARTICLE,1,DIV,0,DIV,1,DIV,0,DIV,0,DIV,0,DIV,2,DIV,0,DIV,1,DIV,0,A,0,H3 selector:div.hds-meet-the-inner > div.hds-meet-the-content > a.display-block > h3.heading-18 snippet:<h3 class="heading-18 color-spacesuit-white link-underline-dashed-light border-carbon…"> type:node] score:0.12394] map[node:map[boundingRect:map[bottom:1688 height:17 left:500 right:568 top:1672 width:68] lhId:page-8-H3 nodeLabel:YouTube path:1,HTML,1,BODY,8,MAIN,0,ARTICLE,1,DIV,0,DIV,1,DIV,0,DIV,0,DIV,0,DIV,2,DIV,0,DIV,1,DIV,0,A,0,H3 selector:div.hds-meet-the-inner > div.hds-meet-the-content > a.display-block > h3.heading-18 snippet:<h3 class="heading-18 color-spacesuit-white link-underline-dashed-light border-carbon…"> 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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

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:27.718 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:64.567 source:map[type:text value:[unattributed]]] map[reflowTime:17.143 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:4.783 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:0.564 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:0.362 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:4.36 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:0.506 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:0.401 source:map[column:33 line:0 type:source-location url: urlProvider:network]] map[reflowTime:0.165 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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Transfer Size	Duration
/Universal-Federated-Analytics-Min.js?agency=NASA&pga4=G-...	9.4 KiB	818 ms
/_static/??-eJyFjMEOwiAQRH/Ida1JbTwYv2Wha0sKC2GBxr+3SS/eO...	33.3 KiB	307 ms

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Request	Cache TTL	Transfer Size
/dynamicimage/assets/science/missions/punch/NFI-CME.png?w...	43200.0 s	2.0 MiB
/image/art002e000192/art002e000192~large.jpg?w=600&h=400&...	300.0 s	384.0 KiB
/image/Artemis II at the pad sunsetting jet in background...	300.0 s	177.4 KiB
/dynamicimage/assets/science/esd/eo/images/iotd/2026/bare...	43200.0 s	203.5 KiB
assets.science.nasa.gov/dynamicimage/assets/science/psd/ares/jsc2026e006229.jpg	43200.0 s	202.5 KiB
/dynamicimage/assets/science/missions/hubble/releases/202...	43200.0 s	187.7 KiB
/dynamicimage/assets/science/hpd/space-weather/SDO_02-04-...	43200.0 s	169.0 KiB
/dynamicimage/assets/science/psd/ares/jsc2026e006229.jpg?...	43200.0 s	134.2 KiB
/dynamicimage/assets/science/esd/eo/images/iotd/2026/fire...	43200.0 s	118.1 KiB
/image/iss074e0325229/iss074e0325229~large.jpg?w=768&h=51...	300.0 s	57.3 KiB
/dynamicimage/assets/science/esd/eo/images/iotd/2026/marc...	43200.0 s	101.2 KiB
/dynamicimage/assets/science/missions/xrism/News/2026/m82...	43200.0 s	74.4 KiB
i.ytimg.com/vi/m3kR2KK8TEs/sddefault.jpg?v=69a88d06	7200.0 s	49.5 KiB
/dynamicimage/assets/science/cds/creative/calendars/2026/...	43200.0 s	68.2 KiB
/dynamicimage/assets/science/missions/webb/science/2026/0...	43200.0 s	40.9 KiB
/dynamicimage/assets/science/esd/eo/images/iotd/2026/réu...	43200.0 s	38.7 KiB
/dynamicimage/assets/science/cds/citizen-science/projects...	43200.0 s	34.5 KiB
/Universal-Federated-Analytics-Min.js?agency=NASA&pga4=G-...	0.0 ms	9.4 KiB
dap.digitalgov.gov/web-vitals/dist/web-vitals.attribution.iife.js	0.0 ms	4.5 KiB
/eIf5fNPcIcj9ig-wZBeq4stFy1lgjWTW1nLT5dYlFkHZprZ03QBiMcbp...	86400.0 s	10.6 KiB
/eIf5fNPcIcj9ig-wZBeq4stFy1lgjWTW1nLT5dYlFkHZprZ03QBiMcbp...	86400.0 s	5.6 KiB
i.ytimg.com/vi/6RwfNBtepa4/default.jpg?v=69c58037	7200.0 s	2.2 KiB
static.doubleclick.net/instream/ad_status.js	900.0 s	494 B
/px/?rand=1775323135676&plid=82b0e1c1-fc70-4334-9abf-2701...	0.0 ms	229 B
/px/?rand=1775323137312&plid=82b0e1c1-fc70-4334-9abf-2701...	0.0 ms	229 B
static.doubleclick.net/instream/ad_status.js	900.0 s	0 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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Est Savings
fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBHMdazQ.woff2	15 ms
fonts.gstatic.com/s/roboto/v48/KFO7CnqEu92Fr1ME7kSn66aGLdTylUAMa3yUBA.woff2	15 ms
/wp-content/client-mu-plugins/uswds-framework/uswds/fonts...	5.0 ms

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

	URL	Resource Size	Est Savings
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/art002e000192/art002e000192~large.jpg?w=600&h=400&...	383.0 KiB	343.9 KiB
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.jpg	201.7 KiB	200.3 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`	/image/Artemis II at the pad sunsetting jet in background...	176.6 KiB	170.8 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.png	47.6 KiB	47.5 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.png	31.7 KiB	31.6 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.png	30.2 KiB	29.1 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.png	23.3 KiB	23.3 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.png	14.0 KiB	14.0 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 KiB	13.9 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 KiB	4.4 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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Element	Layout shift score
Live Views From Orion `div.hds-nasa-live-main > div.grid-container > div.hds-nasa-live-three-column-row > div.grid-col-12`	0.157
YouTube `div.hds-meet-the-inner > div.hds-meet-the-content > a.display-block > h3.heading-18`	0.124
YouTube `div.hds-meet-the-inner > div.hds-meet-the-content > a.display-block > h3.heading-18`	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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Diagnostics

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Total CPU Time	Script Evaluation	Script Parse
www.nasa.gov/	2.4 s	47 ms	2.6 ms
/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVm...	557 ms	362 ms	29 ms
Unattributable	523 ms	9.2 ms	0.0 ms
www.googletagmanager.com/gtag/js?id=G-CSLL4ZEK4L	356 ms	299 ms	54 ms
www.googletagmanager.com/gtag/js?id=G-82GWVTTXCZ&cx=c&gtm=4e6411	345 ms	278 ms	64 ms
www.googletagmanager.com/gtm.js?id=GTM-NLJ258M	326 ms	254 ms	67 ms
www.youtube.com/s/player/f4c47414/www-widgetapi.vflset/www-widgetapi.js	191 ms	166 ms	4.4 ms
cdn.parsely.com/keys/nasa.gov/p.js?ver=3.22.0	146 ms	131 ms	9.2 ms
dap.digitalgov.gov/web-vitals/dist/web-vitals.attribution.iife.js	61 ms	56 ms	1.8 ms

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Category	Time Spent
Script Evaluation	1.7 s
Other	1.3 s
Style & Layout	864 ms
Rendering	719 ms
Script Parsing & Compilation	249 ms
Parse HTML & CSS	172 ms
Garbage Collection	29 ms

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 0.0 ms 39.0 KiB

URL	Transfer Size	Est Savings
/_static/??-eJyFjMEOwiAQRH/Ida1JbTwYv2Wha0sKC2GBxr+3SS/eO...	33.1 KiB	28.6 KiB
/_static/??-eJyFjM0KgzAQBl+o6ZKi5lT6LDFZZHHdCF/86duL6N3Lw...	10.7 KiB	10.4 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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Estimated savings: 0.0 ms 217.2 KiB

URL	Transfer Size	Est Savings
www.googletagmanager.com/gtag/js?id=G-82GWVTTXCZ&cx=c&gtm=4e6411	157.8 KiB	62.7 KiB
www.googletagmanager.com/gtm.js?id=GTM-NLJ258M	128.1 KiB	60.8 KiB
www.googletagmanager.com/gtag/js?id=G-CSLL4ZEK4L	145.5 KiB	57.7 KiB
/_static/??-eJyNzk0OAiEMBeALyRCNGXRhPEsdGwbSFoXi3+nF6MKVm...	63.0 KiB	35.9 KiB

Large network payloads cost users real money and are highly correlated with long load times. Learn how to reduce payload sizes.

Why this matters

Performance issues directly impact user engagement and conversion rates.

URL	Transfer Size
/dynamicimage/assets/science/missions/punch/NFI-CME.png?w...	2.0 MiB
www.nasa.gov/wp-content/uploads/2026/03/gp-headshot.png?resize=768,1152	763.5 KiB
www.youtube.com/s/player/f4c47414/player_embed.vflset/en_US/base.js	465.9 KiB
www.youtube.com/s/player/f4c47414/player_embed_es6.vflset/en_US/base.js	431.3 KiB
/image/art002e000192/art002e000192~large.jpg?w=600&h=400&...	384.0 KiB
/wp-content/uploads/2026/01/a2-cu-horizontal-hero-16-9.pn...	356.8 KiB
www.nasa.gov/wp-content/uploads/2023/06/artemis-base-camp-3-2.png?resize=768,432	316.1 KiB
/videoplayback?expire=1775344736&ei=AEjRaa3bK8-uy_sP2PqGm...	242.9 KiB
/s/_/ytembeds/_/js/k=ytembeds.base.en_US.BgDEvO2q4Ss.es5....	231.8 KiB
/s/_/ytembeds/_/js/k=ytembeds.base.en_US.EkHW-yt-vuI.2021...	207.4 KiB

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 15 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 20 ms

●Server Backend Latencies 80 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

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
02 `div.countdown-item > div.countdown-item-inner > p`
days `div.countdown-item > div.countdown-item-inner > span.label`
18 `div.countdown-item > div.countdown-item-inner > p`
hrs `div.countdown-item > div.countdown-item-inner > span.label`
44 `div.countdown-item > div.countdown-item-inner > p`
mins `div.countdown-item > div.countdown-item-inner > span.label`
00 `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.

Why this matters

Performance issues directly impact user engagement and conversion rates.

Failing Elements
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`
Artemis II Flight Day 2: Crew, Houston Poll ‘Go’ for Translunar Injection Burn `ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a`
Artemis II Flight Update: Perigee Raise Burn Complete `ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a`
Artemis II Flight Update: Crew and Ground Teams Successfully Troubleshoot Orion… `ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a`
Artemis II Flight Update: Proximity Operations Complete, Perigee Raise Burn Up … `ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a`
Artemis II Flight Update: Apogee Raise Burn Complete, Crew Looks Ahead to Proxi… `ul.hds-live-updates-items > li.hds-live-update-item > div.hds-live-update-item-inner > a`
Artemis II Flight Update: Perigee Raise Maneuver Complete; NASA to Hold Press C… `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.

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

Why this matters

Performance issues directly impact user engagement and conversion rates.

Source	Description
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`