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April 18 in spaceflight
Wikipedia records 1 spaceflight and astronomy event on April 18. Below are the pictures NASA published on April 18 in 6 different years — each one taken or released on this exact date.
Recorded events
IN THE RECORD1ENTRY
Spaceflight and astronomy entries from Wikipedia's record of this date, oldest first — from 1915 onward.
Pictures from this date
PUBLISHED6IMAGES
NASA's Astronomy Picture of the Day for April 18, one per year. Some are public domain and some belong to the photographer — each says which.
Published on April 18
NASA’s Astronomy Picture of the Day, for this calendar date in each of the last several years.
2026
PanSTARRS and Planets
Near the eastern horizon before sunrise, Comet C/2025 R3 PanSTARRS is getting brighter. Readily visible in binoculars and small telescopes, the comet may be just on the verge of naked-eye visibility from dark sky sites. Though it was not quite apparent to the eye, PanSTARRS is still easy to spot in this camera image taken on April 16. In the view from a volcanic peak overlooking France's Reunion Island, planet Earth, the comet shares eastern predawn skies with naked-eye planets Mars and Mercury and fainter Neptune. Saturn is hiding behind the low cloudbank that doesn't quite hide an old crescent Moon. This is a good weekend for northern hemisphere comet watchers to try to catch PanSTARRS an hour or so before sunrise, as the comet grows brighter approaching its perihelion on April 19. On April 26 the comet makes its closest approach to our fair planet but by then will be difficult to see in the solar glare. Good views of this comet PanSTARRS in late April and early May will be from the southern hemisphere.
© Luc Perrot — used with the credit NASA publishes
2025
Comet C/2025 F2 SWAN
In late March, the comet now designated C/2025 F2 SWAN was found independently by citizen scientists Vladimir Bezugly, Michael Mattiazzo, and Rob Matson while examining publicly available image data from the Solar Wind ANisotropies (SWAN) camera on the sun-staring SOHO spacecraft. Comet SWAN's coma, its greenish color a signature of diatomic carbon molecules fluorescing in sunlight, is at lower left in this telescopic image. SWAN's faint ion tail extends nearly two degrees toward the upper right across the field of view. The interplanetary scene was captured in clear but moonlit skies from June Lake, California on April 14. Seen against background of stars toward the constellation Andromeda, the comet was then some 10 light-minutes from our fair planet. Now a target for binoculars and small telescopes in northern hemisphere morning skies this comet SWAN is headed for a perihelion, its closest approach to the Sun, on May 1. That will bring this visitor from the distant Oort cloud almost as close to the Sun as the orbit of inner planet Mercury.
© Dan Bartlett — used with the credit NASA publishes
2024
Facing NGC 1232
From our vantage point in the Milky Way Galaxy, we see NGC 1232 face-on. Nearly 200,000 light-years across, the big, beautiful spiral galaxy is located some 47 million light-years away in the flowing southern constellation of Eridanus. This sharp, multi-color, telescopic image of NGC 1232 includes remarkable details of the distant island universe. From the core outward, the galaxy's colors change from the yellowish light of old stars in the center to young blue star clusters and reddish star forming regions along the grand, sweeping spiral arms. NGC 1232's apparent, small, barred-spiral companion galaxy is cataloged as NGC 1232A. Distance estimates place it much farther though, around 300 million light-years away, and unlikely to be interacting with NGC 1232. Of course, the prominent bright star with the spiky appearance is much closer than NGC 1232 and lies well within our own Milky Way.
© Neil Corke — used with the credit NASA publishes
2023
Map of Total Solar Eclipse Path in 2024 April
Would you like to see a total eclipse of the Sun? If so, do any friends or relatives live near the path of next April's eclipse? If yes again, then you might want to arrange a well-timed visit. Next April 8, the path of a total solar eclipse will cross North America from western Mexico to eastern Canada, entering the USA in southern Texas and exiting in northern Maine. All of North America will experience the least a partial solar eclipse. Featured here is a map of the path of totality. Many people who have seen a total solar eclipse tell stories about it for the rest of their lives. As a warmup, an annular solar eclipse will be visible later this year -- in mid-October.
NASA · public domain
2022
Stars and Planets over Portugal
The mission was to document night-flying birds -- but it ended up also documenting a beautiful sky. The featured wide-angle mosaic was taken over the steppe golden fields in Mértola, Portugal in 2020. From such a dark location, an immediately-evident breathtaking glow arched over the night sky: the central band of our Milky Way galaxy. But this sky had much more. Thin clouds crossed the sky like golden ribbons. The planet Mars appeared on the far left, while the planets Saturn and Jupiter were also simultaneously visible -- but on the opposite side of the sky, here seen on the far right. Near the top of the image the bright star Vega can be found, while the far-distant and faint Andromeda Galaxy can be seen toward the left, just below Milky Way's arch. As the current month progresses, several planets are lining up in the pre-dawn sky: Jupiter, Venus, Mars, and Saturn. Did you know? Many APODs have links for adventure & humor
© Miguel Claro (TWAN, Dark Sky Alqueva) — used with the credit NASA publishes
2021
Rainbow Airglow over the Azores
Why would the sky glow like a giant repeating rainbow? Airglow. Now air glows all of the time, but it is usually hard to see. A disturbance however -- like an approaching storm -- may cause noticeable rippling in the Earth's atmosphere. These gravity waves are oscillations in air analogous to those created when a rock is thrown in calm water. The long-duration exposure nearly along the vertical walls of airglow likely made the undulating structure particularly visible. OK, but where do the colors originate? The deep red glow likely originates from OH molecules about 87-kilometers high, excited by ultraviolet light from the Sun. The orange and green airglow is likely caused by sodium and oxygen atoms slightly higher up. The featured image was captured during a climb up Mount Pico in the Azores of Portugal. Ground lights originate from the island of Faial in the Atlantic Ocean. A spectacular sky is visible through this banded airglow, with the central band of our Milky Way Galaxy running up the image center, and M31, the Andromeda Galaxy, visible near the top left. Explore Your Universe: Random APOD Generator
© Miguel Claro (TWAN); Rollover Annotation: Judy Schmidt — used with the credit NASA publishes
What happened on April 18
1915
World War I: Hit by ground fire, French aviation pioneer Roland Garros (pictured) landed his aircraft behind enemy lines and was taken prisoner by German forces.
World War I ↗
Sources and licences
Event text and thumbnails come from Wikipedia and are used under CC BY-SA 4.0. Images are drawn only from Wikimedia Commons, which does not accept non-free content — each thumbnail links to its file page, where its licence and author are recorded.
Launch records are from The Space Devs’ Launch Library 2. This archive is still being mirrored, so some days are incomplete. Pictures are NASA’s Astronomy Picture of the Day; NASA imagery is generally not subject to copyright, but individual APOD entries are frequently the property of the photographer, and each caption says which applies.
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General-audience astronomy and spaceflight — none of it a textbook.
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Cosmos — Carl Sagan
Still the best single argument for why any of this matters, and it leaves the arithmetic in. For a reader who wants the science, not just the awe.
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Pale Blue Dot — Carl Sagan
The case for leaving Earth, written by someone unsentimental about how hard that is. Suits readers who want the argument rather than the poster.
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Project Hail Mary — Andy Weir
Hard-SF problem solving in The Martian's key — for anyone who liked the engineering more than the peril. The only novel on this list.
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