Accessibility
· 13 checks — Landmarks, headings, alt text, forms, and link quality rolled into one auditable list.DLink & Button QualityAction17 issue(s) across 363 links and 25 buttonsFIX
| Element | Text | Issue | Suggested Fix |
|---|---|---|---|
| http://www.facebook.com/NASAHubble | Link to Facebook. | new tab | Add '(opens in new tab)' to text |
| http://twitter.com/NASAHubble | Link to Twitter. | new tab | Add '(opens in new tab)' to text |
| http://instagram.com/NASAHubble | Link to Instagram. | new tab | Add '(opens in new tab)' to text |
| https://science.nasa.gov/missions/hubble… | Article6 Min ReadNASA’s Hubb… | img no alt | Add alt attribute to the image |
| https://science.nasa.gov/missions/hubble… | Article3 Min ReadHubble Spies … | img no alt | Add alt attribute to the image |
| https://science.nasa.gov/missions/hubble… | Article4 Min ReadNASA’s Hubb… | img no alt | Add alt attribute to the image |
| https://science.nasa.gov/missions/webb/n… | Article6 Min ReadNASA Webb, Hu… | img no alt | Add alt attribute to the image |
| https://science.nasa.gov/missions/hubble… | 5 Min ReadNASA Awards Astrophy… | img no alt | Add alt attribute to the image |
| https://science.nasa.gov/missions/hubble… | 4 Min ReadNASA’s Hubble Revi… | img no alt | Add alt attribute to the image |
| https://science.nasa.gov/missions/hubble… | 5 Min ReadNASA’s Hubble Unex… | img no alt | Add alt attribute to the image |
| https://www.nasa.gov/missions/chandra/na… | 6 Min ReadNASA Discovers Crash… | img no alt | Add alt attribute to the image |
| https://science.nasa.gov/missions/hubble… | Learn More | generic text | Replace with descriptive text |
Before: Learn More Suggested: Nasas Hubble Dazzles With Young Stars In Trifid Nebula | |||
| https://science.nasa.gov/gallery/hubbles… | Hubble’s Universe Gallery142… | img no alt | Add alt attribute to the image |
| https://science.nasa.gov/gallery/hubble-… | Hubble Mission Operations Gall… | img no alt | Add alt attribute to the image |
| https://science.nasa.gov/gallery/hubble-… | Hubble Astronauts Gallery46 Im… | img no alt | Add alt attribute to the image |
| https://science.nasa.gov/mission/hubble/… | Read More | generic text | Replace with descriptive text |
Before: Read More Suggested: Hubbles Messier Marathon 2026 | |||
| https://science.nasa.gov/mission/hubble/… | Read More | generic text | Replace with descriptive text |
Before: Read More Suggested: Stellar Construction Zones | |||
| https://science.nasa.gov/mission/hubble/… | Read More | generic text | Replace with descriptive text |
Before: Read More Suggested: Citizen Science | |||
| https://science.nasa.gov/mission/hubble/… | Read More | generic text | Replace with descriptive text |
Before: Read More Suggested: Science Operations | |||
| https://www.nasa.gov/podcasts/universo-c… | Listen Here | new tab | Add '(opens in new tab)' to text |
| https://www.nasa.gov/podcasts/small-step… | Listen Here | new tab | Add '(opens in new tab)' to text |
| https://science.nasa.gov/mission/hubble/… | Read More | generic text | Replace with descriptive text |
Before: Read More Suggested: Ai Hubble Science | |||
| https://science.nasa.gov/mission/hubble/… | Read More | generic text | Replace with descriptive text |
Before: Read More Suggested: Hubble Vs Webb | |||
| https://science.nasa.gov/mission/hubble/… | Read More | generic text | Replace with descriptive text |
Before: Read More Suggested: Science Highlights | |||
| https://science.nasa.gov/mission/hubble/… | Read More | generic text | Replace with descriptive text |
Before: Read More Suggested: Explore The Night Sky | |||
| https://science.nasa.gov/mission/hubble/… | Read More | generic text | Replace with descriptive text |
Before: Read More Suggested: E Books | |||
| https://science.nasa.gov/mission/tess/ | TESS (Transiting Exoplanet Sur… | img no alt | Add alt attribute to the image |
| https://science.nasa.gov/mission/europa-… | Europa Clipper | img no alt | Add alt attribute to the image |
| https://science.nasa.gov/mission/roman-s… | Roman … | img no alt | Add alt attribute to the image |
| https://science.nasa.gov/mission/chandra… | Chandra X-ray Observatory … | img no alt | Add alt attribute to the image |
| https://www.nasa.gov/es/ | NASA en Español | new tab | Add '(opens in new tab)' to text |
| https://www.facebook.com/NASA | NASA on Facebook | new tab | Add '(opens in new tab)' to text |
| https://www.instagram.com/nasa/ | NASA on Instagram | new tab | Add '(opens in new tab)' to text |
| https://x.com/NASA | NASA on X | new tab | Add '(opens in new tab)' to text |
| https://www.youtube.com/@NASA | NASA on YouTube | new tab | Add '(opens in new tab)' to text |
| http://oig.nasa.gov/ | Office of the IG | new tab | Add '(opens in new tab)' to text |
| <button> | (empty) | empty | Add button text or aria-label |
| <button> | (empty) | empty | Add button text or aria-label |
| <button> | (empty) | empty | Add button text or aria-label |
| <button> | (empty) | empty | Add button text or aria-label |
| <button> | (empty) | empty | Add button text or aria-label |
| <button> | (empty) | empty | Add button text or aria-label |
| <button> | (empty) | empty | Add button text or aria-label |
Generic link text like 'click here' doesn't describe the destination.
https://science.nasa.gov/missions/hubble/nasas-hubble-dazzles-with-young-star… ("Learn More"); https://science.nasa.gov/mission/hubble/hubble-news/hubble-social-media/hubbl… ("Read More"); https://science.nasa.gov/mission/hubble/hubble-news/hubble-social-media/stell… ("Read More"); https://science.nasa.gov/mission/hubble/science/citizen-science/ ("Read More"); https://science.nasa.gov/mission/hubble/observatory/science-operations/ ("Read More"); https://science.nasa.gov/mission/hubble/science/ai-hubble-science/ ("Read More"); https://science.nasa.gov/mission/hubble/observatory/hubble-vs-webb/ ("Read More"); https://science.nasa.gov/mission/hubble/science/science-highlights/ ("Read More"); https://science.nasa.gov/mission/hubble/science/explore-the-night-sky/ ("Read More"); https://science.nasa.gov/mission/hubble/multimedia/e-books/ ("Read More")
Generic anchor text ('click here', 'read more', 'learn more') tells screen readers and search engines nothing about the destination.
Learn more ▾ ▴
Out-of-context lists of links read by AT (one navigation pattern) become useless when every link says 'click here'. Use the destination's title or topic as anchor text. Doubles as SEO win — Google passes anchor-text relevance to the destination.
Source: WCAG 2.4.4 / Google Search Central
Add '(opens in new tab)' to link text or aria-label.
http://www.facebook.com/NASAHubble; http://twitter.com/NASAHubble; http://instagram.com/NASAHubble; https://www.nasa.gov/podcasts/universo-curioso-de-la-nasa/el-telescopio-de-la…; https://www.nasa.gov/podcasts/small-steps-giant-leaps/small-steps-giant-leaps…; https://www.nasa.gov/es/; https://www.facebook.com/NASA; https://www.instagram.com/nasa/; https://x.com/NASA; https://www.youtube.com/@NASA (+1 more)
Links with target="_blank" without rel="noopener" leak the originating page's window context — security and UX issue.
Learn more ▾ ▴
Without rel="noopener", the new tab can navigate the original tab via window.opener (tab-nabbing attack). Modern browsers default to noopener for target=_blank but only since recent versions. Always set rel="noopener noreferrer" explicitly.
Source: MDN target / OWASP
Icon-only buttons need an aria-label so screen readers can announce them.
button#global-navigation-trigger--mobile; button.hds-search-panel-mobile-trigger (#137 on page); button.hds-search-panel-bar-close-icon (#242 on page); button.hds-carousel-nav-arrow (#2484 on page); button.hds-carousel-nav-arrow (#2633 on page); button.hds-carousel-nav-arrow (#2751 on page); button.hds-carousel-nav-arrow (#2817 on page)
Buttons with no accessible text (icon-only, no aria-label) can't be activated by voice control or understood by screen readers.
Source: WCAG 2.1 SC 4.1.2
F404 Error PageActionSoft 404 detectedFIX
The server returned HTTP 200 for a non-existent path. Search engines will index this page as real content. Configure your server to return HTTP 404 for missing pages.
FWeb ManifestActionInvalid JSONFIX
Manifest contains invalid JSON.
DDark Mode SupportActionTheme color onlyFIX
Detection limited to meta tags and inline styles.
DPrint StylesheetActionNo print stylesFIX
BLandmark Structure6 landmarksREVIEW
Multiple navigations need aria-label to distinguish them for screen readers.
Some <nav> elements lack aria-label — screen-reader users hear 'navigation' multiple times with no way to distinguish them.
Learn more ▾ ▴
When a page has multiple <nav> regions (primary, footer, breadcrumb), each needs aria-label or aria-labelledby. AT users navigate by landmark; identical 'navigation' announcements force them to enter each one to discover purpose.
Source: WAI-ARIA Authoring Practices
Add a skip link as the first focusable element so keyboard users can bypass repeated navigation.
Without a skip-nav link, keyboard users tab through every nav item before reaching content — every page, every visit.
Learn more ▾ ▴
WCAG 2.4.1 (Bypass Blocks) requires a mechanism to skip past repeated content. The standard implementation is a 'Skip to main content' link that's the first focusable element, visually hidden until focused. Three lines of HTML + four of CSS.
Source: WCAG 2.1 SC 2.4.1
CFavicon & BrandingAction18 icon(s) detectedREVIEW
CColor Contrast (Screenshot)Action20 text elements analyzed, 20 fail WCAG AAREVIEW
Analyzes text contrast against the actual rendered page, including background images, gradients, and overlays that CSS-based tools cannot detect.
Show all checked elements (20)
| Element | Ratio | Required | FG | BG | Result |
|---|---|---|---|---|---|
| h1 Hubble Space Telesco… | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
| h2 Suggested Searches | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
| h2 Latest News | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
| h2 Image Galleries | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
| h2 What Did Hubble See … | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
| h2 More Hubble Interact… | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
| h2 Hubble's Latest Feat… | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
| h2 NASA’s Hubble Capt… | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
| h2 Hubble E-Books | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
| h2 Explore More Hubble | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
| h2 Discover More NASA M… | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
| h3 News & Events | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
| h3 Multimedia | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
| h3 Highlights | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
| h3 Advancing Earth Obse… | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
| h3 NASA’s Curiosity F… | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
| h3 NASA Wins Two Webby … | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
| h3 Missions | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
| h3 Humans in Space | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
| h3 Earth | 1.00:1 | 3.0:1 | #000000 | #000000 | Fail |
Methodology: The top 20 text elements by font size were checked. Background color was sampled from the desktop screenshot using a 5-point pattern. WCAG 2.1 AA requires 4.5:1 for normal text and 3:1 for large text.
A+Heading Hierarchy119 headingsPASS
- H3 News & Events
- H3 Multimedia
- H2 Suggested Searches
- H3 Highlights
- H3 Advancing Earth Observation at NASA Since Release of Earthrise Photo
- H3 NASA’s Curiosity Finds Organic Molecules Never Seen Before on Mars
- H3 NASA Wins Two Webby Awards, Five Webby People’s Voice Awards
- H3 Missions
- H3 Humans in Space
- H3 Earth
- H3 The Solar System
- H3 The Universe
- H3 Science
- H3 Aeronautics
- H3 Technology
- H3 Learning Resources
- H3 About NASA
- H3 NASA en Español
- H3 News & Events
- H3 Multimedia
- H3 Highlights
- H3 NASA’s Curiosity Finds Organic Molecules Never Seen Before on Mars
- H3 NASA on Track for Future Missions with Initial Artemis II Assessments
- H3 NASA’s Hubble Dazzles With Young Stars in Trifid Nebula
- H3 Highlights
- H3 Artemis II Mission Milestones: An Image and Video Recap
- H3 NASA Answers Your Most Pressing Artemis II Questions
- H3 Artemis II Podcast Series
- H3 Highlights
- H3 NASA’s 777 Aircraft Returns Home with Science Flights on the Horizon
- H3 Earth Day 2026: Posters and Virtual Backgrounds
- H3 Advancing Earth Observation at NASA Since Release of Earthrise Photo
- H3 Highlights
- H3 NASA’s Curiosity Finds Organic Molecules Never Seen Before on Mars
- H3 Amendment 51: C.6 Development and Advancement of Lunar Instrumentation Not Solicited in ROSES-25
- H3 Twin NASA Control Rooms Support Artemis Safety, Success
- H3 Highlights
- H3 NASA’s Hubble Dazzles With Young Stars in Trifid Nebula
- H3 ‘Interstellar Glaciers’: NASA’s SPHEREx Maps Vast Galactic Ice Regions
- H3 NASA Finds Young Stars Dim in X-rays Surprisingly Quickly
- H3 Highlights
- H3 NASA’s 777 Aircraft Returns Home with Science Flights on the Horizon
- H3 Integrated Modeling Virtual Institute (IMVI)
- H3 Early Career Investigator Program – Earth Science (ROSES A.11)
- H3 Highlights
- H3 NASA, Organ Sharing Network UNOS to Study Faster Organ Transport
- H3 2025-2026 Dream with Us Design Challenge Winners
- H3 Indoor Testing Facilities available at the NASA Unmanned Autonomy Research Complex (NUARC)
- H3 Highlights
- H3 NASA’s Curiosity Finds Organic Molecules Never Seen Before on Mars
- H3 Amendment 51: C.6 Development and Advancement of Lunar Instrumentation Not Solicited in ROSES-25
- H3 Snow in the Shadow of the Andes
- H3 Highlights
- H3 Join the Artemis Mission to the Moon
- H3 Highlights
- H3 NASA, Organ Sharing Network UNOS to Study Faster Organ Transport
- H3 NASA Wins Two Webby Awards, Five Webby People’s Voice Awards
- H3 Advancing Earth Observation at NASA Since Release of Earthrise Photo
- H3 Highlights
- H3 La NASA anuncia la cobertura de la misión lunar Artemis II
- H3 Agenda diaria de la misión a la Luna de Artemis II de la NASA
- H3 La NASA refuerza Artemis: añade una misión y perfecciona su arquitectura general
- H1 Hubble Space Telescope
- H2 Latest News
- H3 Trifid Nebula Tour
- H2 Image Galleries
- H3 Hubble’s Universe Gallery
- H3 Hubble Mission Operations Gallery
- H3 Hubble Astronauts Gallery
- H2 What Did Hubble See on Your Birthday?
- H2 More Hubble Interactives
- H3 Control Center 360-Degree Tour
- H3 Hearing Hubble
- H3 Hubble’s Cosmic Adventure
- H3 What is Hubble Observing?
- H3 Name that Nebula!
- H3 Lost Universe
- H3 Hubble's Skymap
- H3 Hubble Spacecraft 360 Degree Tour
- H3 Hubble Astronaut Fun Facts
- H3 Control Center 360-Degree Tour
- H3 Hearing Hubble
- H3 Hubble’s Cosmic Adventure
- H3 What is Hubble Observing?
- H3 Name that Nebula!
- H3 Lost Universe
- H3 Hubble's Skymap
- H3 Hubble Spacecraft 360 Degree Tour
- H3 Hubble Astronaut Fun Facts
- H3 Control Center 360-Degree Tour
- H2 Hubble's Latest Features
- H3 Hubble's Messier Marathon 2026
- H3 Hubble's Stellar Construction Zones
- H3 Hubble & Citizen Science
- H3 Science Operations
- H3 Universo curioso de la NASA
- H3 Hubble: An Engineering Marvel
- H3 AI and Hubble Science
- H3 Hubble 3D Models
- H3 New Lithographs
- H2 NASA’s Hubble Captures Light Show Around Rapidly Dying Star
- H2 Hubble E-Books
- H3 Hubble’s Beautiful Universe
- H3 Reshaping Our Cosmic View: Hubble Science Highlights
- H3 Hubble: An Overview of the Space Telescope
- H3 Black Holes: Into the Vortex
- H2 Explore More Hubble
- H3 On The Shoulders of a Giant
- H3 Hubble Science Highlights
- H3 Explore the Night Sky
- H3 Hubble E-books
- H2 You Can Do NASA Science!
- H3 Participate in authentic research via NASA Citizen Science.
- H2 Discover More NASA Missions
- H3 TESS (Transiting Exoplanet Survey Satellite)
- H3 Roman
- H3 Chandra X-ray Observatory
- H3 National Aeronautics and Space Administration
- H3 Follow NASA
AAlt Text QualityAll 96 images OKPASS
| Issue | Count |
|---|---|
| too long | 18 image(s) |
AForm Accessibility1 of 9 controls have issuesPASS
| Control | Type | Label | Method |
|---|---|---|---|
| #search-field-en-small--desktop | search | Search | for/id |
| #search-field-en-small--desktop | search | Search | for/id |
| ak_hp_textarea | textarea | Δ | none |
| #choice_45_1_0 | radio | Yes | for/id |
| #choice_45_1_1 | radio | No | for/id |
| #choice_45_1_2 | radio | Partly | for/id |
| #input_45_3 | textarea | What were you looking for?(Required) | for/id |
| #input_45_4 | textarea | What were you hoping to accomplish by visiting our website?(Required) | for/id |
| #gform_submit_button_45 | submit | (none) | none |
Form controls need a <label>, aria-label, or aria-labelledby for screen readers.
<input type="submit" id="gform_submit_button_45">
Form controls without labels — assistive tech announces 'edit text' with no context; users can't complete forms.
Source: WCAG 2.1 SC 3.3.2
A+Lighthouse Accessibility AuditsScore 95/100 — 1 failing, 27 passedPASS
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.
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 |
div.hds-card-carousel > div.hds-card-carousel-cards > div.hds-cards-included > button.hds-carousel-nav-arrow div.hds-card-carousel > div.hds-card-carousel-cards > div.hds-cards-included > button.hds-carousel-nav-arrow |
div.hds-card-carousel > div.hds-card-carousel-cards > div.hds-cards-included > button.hds-carousel-nav-arrow div.hds-card-carousel > div.hds-card-carousel-cards > div.hds-cards-included > button.hds-carousel-nav-arrow |
div.hds-card-carousel > div.hds-card-carousel-cards > div.hds-cards-included > button.hds-carousel-nav-arrow div.hds-card-carousel > div.hds-card-carousel-cards > div.hds-cards-included > button.hds-carousel-nav-arrow |
div.hds-card-carousel > div.hds-card-carousel-cards > div.hds-cards-included > button.hds-carousel-nav-arrow div.hds-card-carousel > div.hds-card-carousel-cards > div.hds-cards-included > button.hds-carousel-nav-arrow |
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.