Launches
NO DATA0MISSIONS
The launch archive is still being mirrored, so this day has no launches listed yet.
ARCHIVE // DAY OF YEAR
Wikipedia records 6 spaceflight and astronomy events on April 17. Below are the pictures NASA published on April 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.
6ENTRIES
Spaceflight and astronomy entries from Wikipedia's record of this date, oldest first — from 1964 onward.
5IMAGES
NASA's Astronomy Picture of the Day for April 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.

2026
Messier 82 is a starburst galaxy with a superwind. In fact, through supernova explosions and powerful winds from massive stars, the burst of star formation in M82 is driving a prodigious outflow. Evidence for the superwind from the galaxy's central regions is clear in the sharp telescopic portrait. The composite image includes 33 hours of narrowband data, highlighting emission from long outflow filaments of atomic hydrogen gas in reddish hues. Some of the gas in the superwind, enriched in heavy elements forged in the massive stars, will eventually escape into intergalactic space. Triggered by a close encounter with nearby large galaxy M81, the furious burst of star formation in M82 should last about 100 million years or so. Also known as the Cigar Galaxy for its elongated visual appearance, M82 is about 30,000 light-years across. It lies 12 million light-years away near the northern boundary of Ursa Major.
© Arnaud Malleval — used with the credit NASA publishes

2024
Not one, but two comets appeared near the Sun during last week's total solar eclipse. The expected comet was Comet 12P/Pons-Brooks, but it was disappointingly dimmer than many had hoped. However, relatively unknown Comet SOHO-5008 also appeared in long duration camera exposures. This comet was the 5008th comet identified on images taken by ESA & NASA's Sun-orbiting SOHO spacecraft. Likely much smaller, Comet SOHO-5008 was a sungrazer which disintegrated within hours as it passed too near the Sun. The featured image is not only unusual for capturing two comets during an eclipse, but one of the rare times that a sungrazing comet has been photographed from the Earth's surface. Also visible in the image is the sprawling corona of our Sun and the planets Mercury (left) and Venus (right). Of these planets and comets, only Venus was easily visible to millions of people in the dark shadow of the Moon that crossed North America on April 8. Solar Eclipse Imagery: Notable Submissions to APOD
© Lin Zixuan (Tsinghua U.) — used with the credit NASA publishes

2023
What's that red ring in the sky? Lightning. The most commonly seen type of lightning involves flashes of bright white light between clouds. Over the past 50 years, though, other types of upper-atmospheric lightning have been confirmed, including red sprites and blue jets. Less well known and harder to photograph is a different type of upper atmospheric lightning known as ELVES. ELVES are thought to be created when an electromagnetic pulse shoots upward from charged clouds and impacts the ionosphere, causing nitrogen molecules to glow. The red ELVES ring pictured had a radius of about 350 km and was captured in late March about 100 kilometers above Ancona, Italy. Years of experience and ultra-fast photography were used to capture this ELVES -- which lasted only about 0.001 second.
© Valter Binotto — used with the credit NASA publishes

2022
What's that approaching? Astronauts on board the International Space Station in 2010 first saw it far in the distance. Soon it enlarged to become a dark silhouette. As it came even closer, the silhouette appeared to be a spaceship. Finally, the object revealed itself to be the Space Shuttle Endeavour, and it soon docked as expected with the Earth-orbiting space station. Pictured here, Endeavour was imaged near Earth's horizon as it approached, where several layers of the Earth's atmosphere were visible. Directly behind the shuttle is the mesosphere, which appears blue. The atmospheric layer that appears white is the stratosphere, while the orange layer is Earth's Troposphere. Together, these thin layers of air -- collectively spanning less than 2 percent of Earth's radius -- sustain us all in many ways, including providing oxygen to breath and a barrier to dangerous radiations from space. Coming up Friday: Earth Day 2022
NASA · public domain

2021
The Flame Nebula is a stand out in optical images of the dusty, crowded star forming regions toward Orion's belt and the easternmost belt star Alnitak, a mere 1,400 light-years away. Alnitak is the bright star at the right edge of this infrared image from the Spitzer Space Telescope. About 15 light-years across, the infrared view takes you inside the nebula's glowing gas and obscuring dust clouds though. It reveals many stars of the recently formed, embedded cluster NGC 2024 concentrated near the center. The stars of NGC 2024 range in age from 200,000 years to 1.5 million years young. In fact, data indicate that the youngest stars are concentrated near the middle of the Flame Nebula cluster. That's the opposite of the simplest models of star formation for a stellar nursery that predict star formation begins in the denser center of a molecular cloud core. The result requires a more complex model for star formation inside the Flame Nebula.
NASA · public domain
1964
Jerrie Mock completes the first around-the-world airplane flight by a woman. Her solo flight in the Spirit of Columbus, which took 29+1⁄2 days, took off and landed at the Port Columbus International Airport in Ohio.
Jerrie Mock ↗1978
Mir Akbar Khyber is assassinated, provoking the Saur Revolution in Afghanistan.
Mir Akbar Khyber ↗1998
Space Shuttle Columbia is launched on STS-90, the final Spacelab mission.
Space Shuttle Columbia ↗2014
NASA announced the discovery of Kepler-186f, the first exoplanet with a radius similar to Earth's discovered in the habitable zone of another star.
NASA ↗2014
NASA's Kepler space telescope confirms the discovery of the first Earth-size planet in the habitable zone of another star.
NASA ↗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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