Launches
NO DATA0MISSIONS
The launch archive is still being mirrored, so this day has no launches listed yet.
ARCHIVE // DAY OF YEAR
Wikipedia records 4 spaceflight and astronomy events on September 17. Below are the pictures NASA published on September 17 in 5 different years — each one taken or released on this exact date.
0MISSIONS
The launch archive is still being mirrored, so this day has no launches listed yet.
4ENTRIES
Spaceflight and astronomy entries from Wikipedia's record of this date, oldest first — from 1908 onward.
5IMAGES
NASA's Astronomy Picture of the Day for September 17, one per year. Some are public domain and some belong to the photographer — each says which.
NASA’s Astronomy Picture of the Day, for this calendar date in each of the last several years.

2025
Can you spot famous celestial objects in this image? 18th-century astronomer Charles Messier cataloged only two of them: the bright Lagoon Nebula (M8) at the bottom, and the colorful Trifid Nebula (M20) at the upper right. The one on the left that resembles a cat's paw is NGC 6559, and it is much fainter than the other two. Even harder to spot are the thin blue filaments on the left, from supernova remnant (SNR G007.5-01.7). Their glow comes from small amounts of glowing oxygen atoms that are so faint that it took over 17 hours of exposure with just one blue color to bring up. Framing this scene of stellar birth and death are two star clusters: the open cluster M21 just above Trifid, and the globular cluster NGC 6544 at lower left.
© J. De Winter, C. Humbert, C. Robert & V. Sabet; Text: Ogetay Kayali (MTU) — used with the credit NASA publishes

2024
Cosmic clouds form fantastic shapes in the central regions of emission nebula IC 1805. The clouds are sculpted by stellar winds and radiation from massive hot stars in the nebula's newborn star cluster, Melotte 15. About 1.5 million years young, the cluster stars are scattered in this colorful skyscape, along with dark dust clouds in silhouette against glowing atomic gas. A composite of narrowband and broadband telescopic images, the view spans about 15 light-years and includes emission from ionized hydrogen, sulfur, and oxygen atoms mapped to green, red, and blue hues in the popular Hubble Palette. Wider field images reveal that IC 1805's simpler, overall outline suggests its popular name - the Heart Nebula. IC 1805 is located about 7,500 light years away toward the boastful constellation Cassiopeia.
© Richard McInnis — used with the credit NASA publishes

2023
What are those dark streaks in this composite image of a solar eclipse? They are reversed shadows of mountains at the edge of the Moon. The center image, captured from Xiamen, China, has the Moon's center directly in front of the Sun's center. The Moon, though, was too far from the Earth to completely block the entire Sun. Light that streamed around the edges of the Moon is called a ring of fire. Images at each end of the sequence show sunlight that streamed through lunar valleys. As the Moon moved further in front of the Sun, left to right, only the higher peaks on the Moon's perimeter could block sunlight. Therefore, the dark streaks are projected, distorted, reversed, and magnified shadows of mountains at the Moon's edge. Bright areas are called Baily's Beads. Only people in a narrow swath across Earth's Eastern Hemisphere were able to view this full annular solar eclipse in 2020. Next month, though, a narrow swath crossing both North and South America will be exposed to the next annular solar eclipse. And next April, a total solar eclipse will be visible across North America. Open Science: Browse 3,000+ codes in the Astrophysics Source Code Library
© Wang Letian (Eyes at Night) — used with the credit NASA publishes

2022
The Perseverance rover's Mastcam-Z captured images to create this mosaic on August 4, 2022. The car-sized robot was continuing its exploration of the fan-shaped delta of a river that, billions of years ago, flowed into Jezero Crater on Mars. Sedimentary rocks preserved in Jezero's delta are considered one of the best places on Mars to search for potential signs of ancient microbial life and sites recently sampled by the rover, dubbed Wildcat Ridge and Skinner Ridge, are at lower left and upper right in the frame. The samples taken from these areas were sealed inside ultra-clean sample tubes, ultimately intended for return to Earth by future missions. Starting with the Pathfinder Mission and Mars Global Surveyor in 1997, the last 25 years of a continuous robotic exploration of the Red Planet has included orbiters, landers, rovers, and a helicopter from planet Earth.
NASA · public domain

2021
There has been a flash on Jupiter. A few days ago, several groups monitoring our Solar System's largest planet noticed a two-second long burst of light. Such flashes have been seen before, with the most famous being a series of impactor strikes in 1994. Then, fragments of Comet Shoemaker-Levy 9 struck Jupiter leaving dark patches that lasted for months. Since then, at least seven impacts have been recorded on Jupiter -- usually discovered by amateur astronomers. In the featured video, variations in the Earth's atmosphere cause Jupiter's image to shimmer when, suddenly, a bright flash appears just left of center. Io and its shadow are visible on the right. What hit Jupiter will likely never be known, but considering what we do know of the nearby Solar System, it was likely a piece of rock and ice -- perhaps the size of a bus -- that broke off long-ago from a passing comet or asteroid.
© T. Humbert, S. Barré, A. Desmougin & D. Walliang (Société Lorraine d'Astronomie), Astroqueyras — used with the credit NASA publishes
1908
The Wright Flyer flown by Orville Wright, with Lieutenant Thomas Selfridge as passenger, crashes, killing Selfridge, who becomes the first airplane fatality.
Wright Flyer ↗1991
Estonia, North Korea, South Korea, Latvia, Lithuania, the Marshall Islands and Micronesia join the United Nations.
Estonia ↗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.
General-audience astronomy and spaceflight — none of it a textbook.
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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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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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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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