Launches
NO DATA0MISSIONS
The launch archive is still being mirrored, so this day has no launches listed yet.
ARCHIVE // DAY OF YEAR
August 21 in spaceflight
Wikipedia records 7 spaceflight and astronomy events on August 21. Below are the pictures NASA published on August 21 in 5 different years — each one taken or released on this exact date.
Recorded events
IN THE RECORD7ENTRIES
Spaceflight and astronomy entries from Wikipedia's record of this date, oldest first — from 1808 onward.
Pictures from this date
PUBLISHED5IMAGES
NASA's Astronomy Picture of the Day for August 21, one per year. Some are public domain and some belong to the photographer — each says which.
Published on August 21
NASA’s Astronomy Picture of the Day, for this calendar date in each of the last several years.
2025
Mostly Perseids
In this predawn skyscape recorded during the early morning hours of August 13, mostly Perseid meteors are raining down on planet Earth. You can easily identify the Perseid meteor streaks. They're the ones with trails that seem to converge on the annual meteor shower's radiant, a spot in the heroic constellation Perseus, located off the top of the frame. That's the direction in Earth's sky that looks along the orbit of this meteor shower's parent, periodic Comet Swift-Tuttle. Of course the scene is a composite, a combination of about 500 digital exposures to capture meteors registered with a single base frame exposure. But all exposures were taken during a period of around 2.5 hours from a wind farm near Mönchhof, Burgenland, Austria. Red lights on the individual wind turbine towers dot the foreground. In their spectacular close conjunction, bright planets Jupiter and Venus are poised above the eastern horizon.
© Klaus Pillwatsch — used with the credit NASA publishes
2024
Fermi's 12-year All-Sky Gamma-ray Map
Forget X-ray vision — imagine what you could see with gamma-ray vision! The featured all-sky map shows what the universe looks like to NASA's Fermi Gamma-ray Space Telescope. Fermi sees light with energies about a billion times what the human eye can see, and the map combines 12 years of Fermi observations. The colors represent the brightness of the gamma-ray sources, with brighter sources appearing lighter in color. The prominent stripe across the middle is the central plane of our Milky Way galaxy. Most of the red and yellow dots scattered above and below the Milky Way’s plane are very distant galaxies, while most of those within the plane are nearby pulsars. The blue background that fills the image is the diffuse glow of gamma-rays from distant sources that are too dim to be detected individually. Some gamma-ray sources remain unidentified and topics of research — currently no one knows what they are.
NASA · public domain
2023
Introducing Comet Nishimura
Will Comet Nishimura become visible to the unaided eye? Given the unpredictability of comets, no one can say for sure, but it currently seems like a good bet. The comet was discovered only ten days ago by Hideo Nishimura during 30-second exposures with a standard digital camera. Since then, C/2023 P1 Nishimura has increased in brightness and its path across the inner Solar System determined. As the comet dives toward the Sun, it will surely continue to intensify and possibly become a naked-eye object in early September. A problem is that the comet will also be angularly near the Sun, so it will only be possible to see it near sunset or sunrise. The comet will get so close to the Sun -- inside the orbit of planet Mercury -- that its nucleus may break up. Pictured, Comet Nishimura was imaged three days ago from June Lake, California, USA while sporting a green coma and a thin tail.
© Dan Bartlett — used with the credit NASA publishes
2022
The Spinning Pulsar of the Crab Nebula
At the core of the Crab Nebula lies a city-sized, magnetized neutron star spinning 30 times a second. Known as the Crab Pulsar, it is the bright spot in the center of the gaseous swirl at the nebula's core. About twelve light-years across, the spectacular picture frames the glowing gas, cavities and swirling filaments near the Crab Nebula's center. The featured picture combines visible light from the Hubble Space Telescope in purple, X-ray light from the Chandra X-ray Observatory in blue, and infrared light from the Spitzer Space Telescope in red. Like a cosmic dynamo the Crab pulsar powers the emission from the nebula, driving a shock wave through surrounding material and accelerating the spiraling electrons. With more mass than the Sun and the density of an atomic nucleus,the spinning pulsar is the collapsed core of a massive star that exploded. The outer parts of the Crab Nebula are the expanding remnants of the star's component gasses. The supernova explosion was witnessed on planet Earth in the year 1054. Explore Your Universe: Random APOD Generator
NASA · public domain
2021
Triple Transit and Mutual Events
These three panels feature the Solar System's ruling gas giant Jupiter on August 15 as seen from Cebu City, Philippines, planet Earth. On that date the well-timed telescopic views detail some remarkable performances, transits and mutual events, by Jupiter's Galilean moons. In the top panel, Io is just disappearing into Jupiter's shadow at the far right, but the three other large Jovian moons appear against the planet's banded disk. Brighter Europa and darker Ganymede are at the far left, also casting their two shadows on the gas giant's cloud tops. Callisto is below and right near the planet's edge, the three moons in a triple transit across the face of Jupiter. Moving to the middle panel, shadows of Europa and Ganymede are still visible near center but Ganymede has occulted or passed in front of Europa. The bottom panel captures a rare view of Jovian moons in eclipse while transiting Jupiter, Ganymede's shadow falling on Europa itself. From planet Earth's perspective, similar mutual events, when Galilean moons occult and eclipse each other, can be seen every six years or so when Jupiter is near its own equinox.
© Christopher Go — used with the credit NASA publishes
What happened on August 21
1808
Battle of Vimeiro: British and Portuguese forces led by General Arthur Wellesley defeat French force under Major-General Jean-Andoche Junot near the village of Vimeiro, Portugal, the first Anglo-Portuguese victory of the Peninsular War.
Battle of Vimeiro ↗
1810
Jean-Baptiste Bernadotte, Marshal of France, is elected Crown Prince of Sweden by the Swedish Riksdag of the Estates.
Charles XIV John ↗
1945
American physicist Harry Daghlian accidentally dropped a tungsten carbide brick onto a plutonium bomb core, exposing himself to neutron radiation and later becoming the first Manhattan Project fatality due to a criticality accident.
Harry Daghlian ↗1945
Physicist Harry Daghlian is fatally irradiated in a criticality accident during an experiment with the Demon core at Los Alamos National Laboratory.
Harry Daghlian ↗
2013
Syrian civil war: Areas controlled by the Syrian opposition in Ghouta, Damascus, were attacked by rockets (launcher pictured) containing sarin, killing at least 281 people.
Syrian civil war ↗
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.
FIELD KIT / LIBRARY
SPONSORED
General-audience astronomy and spaceflight — none of it a textbook.
As an Amazon Associate I earn from qualifying purchases. Links here cost you nothing extra.
- VIEW
LISTING
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.
- VIEW
LISTING
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.
- VIEW
LISTING
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.
BROWSE opens an Amazon search, not a specific recommendation.
LINKS AMAZON.COM