Launches
ON RECORD43MISSIONS
39 of them reached orbit. The earliest was 1961, the most recent 2025.
MARKED ON THIS DATE
1968 · 58 years ago today
Apollo 8 leaves for the Moon
Apollo 8 became the first crewed flight to leave Earth orbit, three months after the decision to send it was taken.
read more2015 · 11 years ago today
The first orbital booster landing
A Falcon 9 first stage returned to Cape Canaveral and landed upright after delivering eleven satellites to orbit.
read moreARCHIVE // DAY OF YEAR
43 orbital launches flew on December 21, the earliest of them in 1961, and 39 reached orbit. Wikipedia records 6 spaceflight and astronomy events on December 21. Below are the pictures NASA published on December 21 in 5 different years — each one taken or released on this exact date.
43MISSIONS
39 of them reached orbit. The earliest was 1961, the most recent 2025.
6ENTRIES
Spaceflight and astronomy entries from Wikipedia's record of this date, oldest first — from 1844 onward.
5IMAGES
NASA's Astronomy Picture of the Day for December 21, 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
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
NASA · public domain

2024
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
© Wael Omar — used with the credit NASA publishes

2023
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
© Dan Bartlett — used with the credit NASA publishes

2022
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
© Goran Strand — used with the credit NASA publishes

2021
Discover the cosmos! Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer.
© Stefan Seip — used with the credit NASA publishes
1844
The Rochdale Pioneers opened their store (pictured) in Rochdale, England, forming the basis for the modern co-operative movement.
Rochdale Society of Equitable Pioneers ↗1844
The Rochdale Society of Equitable Pioneers commences business at its cooperative in Rochdale, England, starting the Cooperative movement.
Rochdale Society of Equitable Pioneers ↗1968
Apollo 8 launched from Kennedy Space Center in Florida on a trajectory to the Moon; its crew (pictured) became the first humans to visit another celestial body.
Apollo 8 ↗1968
Apollo program: Apollo 8 is launched from the Kennedy Space Center, placing its crew on a lunar trajectory for the first visit to another celestial body by humans.
Apollo program ↗2020
A great conjunction of Jupiter and Saturn occurs, with the two planets separated in the sky by 0.1 degrees. This is the closest conjunction between the two planets since 1623.
Great conjunction ↗General-audience astronomy and spaceflight — none of it a textbook.
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LISTING
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.
LISTING
The case for leaving Earth, written by someone unsentimental about how hard that is. Suits readers who want the argument rather than the poster.
LISTING
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
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. 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.