Launches
NO DATA0MISSIONS
The launch archive is still being mirrored, so this day has no launches listed yet.
ARCHIVE // DAY OF YEAR
April 6 in spaceflight
Wikipedia records 5 spaceflight and astronomy events on April 6. Below are the pictures NASA published on April 6 in 5 different years — each one taken or released on this exact date.
Recorded events
IN THE RECORD5ENTRIES
Spaceflight and astronomy entries from Wikipedia's record of this date, oldest first — from 1965 onward.
Pictures from this date
PUBLISHED5IMAGES
NASA's Astronomy Picture of the Day for April 6, one per year. Some are public domain and some belong to the photographer — each says which.
Published on April 6
NASA’s Astronomy Picture of the Day, for this calendar date in each of the last several years.
2025
Moonquakes Surprisingly Common
Why are there so many moonquakes? Analyses of seismometers left on the moon during the Apollo moon landings reveal a surprising number of moonquakes occurring within 100 kilometers of the surface. In fact, 62 moonquakes were detected in data recorded between 1972 and 1977. Many of these moonquakes are not only strong enough to move furniture in a lunar apartment, but the stiff rock of the moon continues to vibrate for many minutes, significantly longer than the softer rock earthquakes on Earth. The cause of the moonquakes remains unknown, but a leading hypothesis includes tidal gravity from -- and relative heating by -- our Earth. Regardless of the source, future moon dwellings need to be built to withstand the frequent shakings. Pictured here, Apollo 11 astronaut Buzz Aldrin stands beside a recently deployed lunar seismometer, looking back toward the lunar landing module. Explore Your Universe: Random APOD Generator
NASA · public domain
2024
Unwinding M51
The arms of a grand design spiral galaxy 60,000 light-years across are unwound in this digital transformation of the magnificent 2005 Hubble Space Telescope portrait of M51. In fact, M51 is one of the original spiral nebulae, its winding arms described by a mathematical curve known as a logarithmic spiral, a spiral whose separation grows in a geometric way with increasing distance from the center. Applying logarithms to shift the pixel coordinates in the Hubble image relative to the center of M51 maps the galaxy's spiral arms into diagonal straight lines. The transformed image dramatically shows the arms themselves are traced by star formation, lined with pinkish starforming regions and young blue star clusters. Companion galaxy NGC 5195 (top) seems to alter the track of the arm in front of it though, and itself remains relatively unaffected by this unwinding of M51. Also known as the spira mirabilis, logarthimic spirals can be found in nature on all scales. For example, logarithmic spirals can also describe hurricanes, the tracks of subatomic particles in a bubble chamber and, of course, cauliflower. NASA Coverage: Total Solar Eclipse of 2024 April 8
© Hubble Heritage Project — used with the credit NASA publishes
2023
Terran 1 Burns Methalox
Relativity's Terran 1 Rocket is mostly 3D-printed. It burns a cryogenic rocket fuel composed of liquid methane and liquid oxygen (methalox). In this close-up of a Terran 1 launch on the night of March 22 from Cape Canaveral, icy chunks fall through the stunning frame as intense blue exhaust streams from its nine Aeon 1 engines. In a largely successful flight the inovative rocket achieved main engine cutoff and stage separation but fell short of orbit after an anomaly at the beginning of its second stage flight. Of course this Terran 1 rocket was never intended to travel to Mars. Still, the methane and liquid oxygen components of its methalox fuel can be made solely from materials found on the Red Planet. Methalox manufactured on Mars could be used as fuel for rockets returning to planet Earth.
NASA · public domain
2022
Earendel: A Star in the Early Universe
Is Earendel the farthest star yet discovered? This scientific possibility started when the Hubble Space Telescope observed a huge cluster of galaxies. The gravitational lens effect of this cluster was seen to magnify and distort a galaxy far in the background. This distorted background galaxy -- so far away it has a redshift of 6.2 -- appears in the featured image as a long red string, while beads on that string are likely to be star clusters. The galaxy cluster lens creates a line of maximum magnification line where superposed background objects may appear magnified many thousands of times. On the intersection between the galaxy line and the maximum magnification line is one "bead" which shows evidence of originating from a single bright star in the early universe -- now named Earendel. Future investigations may include more imaging by Hubble to see how Earendel's brightness varies, and, quite possibly, by the new James Webb Space Telescope when it becomes operational later this year. Earendel's great distance exceeds that of any known stable star -- although the star that exploded creating GRB 090423 had a redshift of 8.2.
NASA · public domain
2021
Mars and the Pleiades Beyond Vinegar Hill
Is this just a lonely tree on an empty hill? To start, perhaps, but look beyond. There, a busy universe may wait to be discovered. First, physically, to the left of the tree, is the planet Mars. The red planet, which is the new home to NASA's Perseverance rover, remains visible this month at sunset above the western horizon. To the tree's right is the Pleiades, a bright cluster of stars dominated by several bright blue stars. The featured picture is a composite of several separate foreground and background images taken within a few hours of each other, early last month, from the same location on Vinegar Hill in Milford, Nova Scotia, Canada. At that time, Mars was passing slowly, night after night, nearly in front of the distant Seven Sisters star cluster. The next time Mars will pass angularly as close to the Pleiades as it did in March will be in 2038.
© Kristine Richer — used with the credit NASA publishes
What happened on April 6
1965
Launch of Early Bird, the first commercial communications satellite to be placed in geosynchronous orbit.
Intelsat I ↗
1985
Sudanese President Gaafar Nimeiry is ousted from power in a coup d'état led by Field Marshal Abdel Rahman Swar al-Dahab.
Gaafar Nimeiry ↗
2026
During the Artemis II mission, the Orion made its closest approach to the far side of the Moon and reached its greatest distance from Earth .
Artemis II ↗2026
The crew of Artemis II makes the first crewed circumlunar flight since Apollo 17 in 1972, returning humanity to the Moon's vicinity and breaking Apollo 13's record by ~4,000 miles as the furthest crewed spaceflight.
Artemis II ↗
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