Luna 9 – The First Lunar Soft-Landing

The Soviets claimed many firsts in their space race with the United States. First person in space (and orbit), first woman in space, first satellite in orbit. Most would agree, however, that the United States accomplished the biggest first by being the first (and to this day, only) to land humans on the Moon. But the Soviet space program did claim a important lunar firsts of their own: the first lunar fly-by, the first pictures of the far side of the Moon, and the first soft-landing of a probe on the Moon’s surface.

Luna 9 model

Luna 9 model – Source:

On February 3, 1966, the Soviet spacecraft, Luna 9, completed its 3-day journey to the Moon and landed safely on the lunar surface. This ‘soft-landing’ (as in: not a crash-landing) marked the first time a human-made craft survived a landing on any body other than Earth. The successful landing was accomplished by a number of systems that all had to work flawlessly: inflation of an airbag system to cushion the impact, the retrorocket burn to slow the craft, and the deployment of a contact sensor to determine the precise altitude above the Moon. At an altitude of 5 meters, the contact sensor was triggered: engines were shut off and the landing capsule was ejected. Though the craft’s speed was reduced significantly, it still impacted the Moon at a velocity of 22 km/hr (13.7 miles per hour). The airbags allowed the capsule to safely bounce several times before it came to rest.

Following landing and an approximately four-minute pause, four petals that served as the craft’s shell unfolded and stabilized the probe the ground. Antennas were deployed and the craft’s television camera began recording the lunar landscape, capturing the first views ever seen from the surface of the Moon. In addition to the images and radiation readings, the landing also disproved models that suggested that the Moon was covered in a thick layer of dust that would cause any craft (and eventually, persons) who landed there to sink.

One of the first images taken from the Moon's surface

One of the first images taken from the Moon’s surface – Source: Smithsonian National Air and Space Museum

Luna 9’s batteries lasted for three days after landing, during which the craft was able to record a number of panoramic images and beam them back to Earth.

Joddrell Bank, the British observatory located at the University of Manchester, had been paying close attention to the race between the Soviets and the United States. Scientists there not only tracked Luna 9’s progress, but they also recognized the type of signal that the craft was beaming back. They deployed the correct receiving equipment and were able to acquire the lunar images and publish them before the Soviets even managed to see them. There’s still debate as to whether the Soviet scientists let this happen on purpose or not.

While the Soviets soft-landed their craft first, the United States wasn’t far behind. Three months after Luna 9, the US landed Surveyor 1 on the Moon’s surface. Various robots continued to explore the Moon, paving the way for the humans that followed them. After the United States stopped sending astronauts to the Moon in 1972, the next soft-landing wouldn’t occur until 2013, when the Chinese lander Chang’e-3 brought the rover Yutu to explore our celestial neighbor.

Alien Footprints

Ever wondered about the track’s humanity has left on other worlds? If so, you’ll probably appreciate this infographic from Karl Tate and

View the list of extraterrestrial vehicles and distances traveled on other worlds.

Source All about our solar system, outer space and exploration

It’s a fairly intuitive image, so there’s not a lot I need to say. I’m jealous of the miles of tracks that were laid down by the Apollo astronauts in their moon buggies. Could you imagine?

I hope to live long enough to see just as many human-driven miles on Mars.

Upcoming Solar Eclipse

Readers located in the Western United States and East Asia should mark their calendars for this Sunday’s (May 20, 2012) solar eclipse. To some degree, the eclipse should be observable from Texas to Thailand, with certain locales observing an annular eclipse, while others will still get the treat of a partial eclipse.

Track of the May 20, 2012 solar eclipse overlaid on a map.

(Image courtesy of Google and NASA’s Eclipse Web Site)

 Note, you do not need to be on that path in the picture above to see the eclipse. If you’re within that path, you will see an annular eclipse. If you’re North of South of that path, you’ll see a partial eclipse. An annular eclipse is a solar eclipse in which the distance between the Earth and the Moon is great enough that it appears too small to completely block out the Sun. It will look like this:

Eclipse Anular

Photo of a 2005 annular eclipse, as seen from Spain. Photographed by Abel Pardo López and used under a Creative Commons license. Click image for source.

Unlike the case with a total eclipse, where the Moon is closer to Earth and covers the entire Sun (less its corona), do not look directly at an annular eclipse with your naked eyes!

For those of us that will be outside the path of the annular eclipse, many will still be able to see a partial eclipse. Without going too deep into the geometry of an eclipse, be aware that there are basically three types of shadows produced during the event: the umbra, antumbra,  and penumbra. The umbra is the darkest part of the Moon’s shadow, and when it falls upon the Earth it results in a total eclipse. From within the umbra, the Sun is completely blocked out by the Moon. From the vantage point of an observer within the penumbra, the Sun is only partially blocked by the Moon, resulting in a partial eclipse.  Within the antumbra, an observer will see the Moon pass completely between them and the Sun, however its apparent size compared to the Sun will be small enough that it will not completely block out the Sun; an annular eclipse.

The following diagram is a visual demonstration of what I’ve just described:

Diagram showing the different types of solar eclipses.

(Image Credit: University of Tennessee Department of Physics and Astronomy)

“Okay, but I just want to know if I can see it!”

Okay, so you want to know if you’ll be able to see the eclipse, and if so, when should you look? The best and simplest way to find out is to go to NASA’s Eclipse Web Site for this event. From there, you can click on your location on the map and a little window will pop up with details, like so:

Details of the May 20, 2012 solar eclipse for Kenai, Alaska

If you live near Kenai, Alaska (like me) there are your details. Take note that the times are in Coordinated Universal Time (UTC), so you’ll want to adjust accordingly based on your time zone. In my local case the eclipse will begin at around 3:15pm local time (UTC – 9 [AK Time] + 1 [Daylight Savings Time]) and continue for nearly three hours, as the Moon slowly moves across the face of the Sun. For other locations, you’ll find this tool very easy to use.

“What good is knowing when and where an annular eclipse is if I’m not allowed to look at it?!”

I’m glad you asked! By all means, do NOT look at this eclipse with your naked eyes. You will damage them. The visual part of the electromagnetic spectrum is far too beautiful to go damaging your instruments to see it (your eyes!). Fortunately, there are a few simple tools you can use to view it.

The most convenient method is to use cheap cardboard solar-shield glasses made specifically for this purpose. You can buy them online and elsewhere for less than a dollar. (Buy many and share! They’ll also be great for the Venus transit next month, but more on that later!) They look like this:

Solar shield glasses

If you choose to purchase some (there may not be enough time to receive them before Sunday, but there will be plenty of future opportunities to use them as well), I recommend purchasing through a company associated with Astronomers Without Borders, where proceeds will go to benefit others interested in astronomy. Make sure any you use are clearly labeled that they’re safe to view the Sun through.  An alternative to these glasses is to use Number 14 Welders’ Glass, available at welding supply shops.

You can also use a pair of binoculars or a telescope as follows, but make sure that nobody (small children, non-bright adults, pets) looks at the Sun through the eyepieces; it could very well be the last thing they see. To use binoculars or a telescope, you want to project the image onto a piece of shaded white paper. Just align the Sun with the objective lens (not the eyepiece lens) and let the light pass through and onto the piece of paper. An image of the Sun will appear on the paper and, while bright, will be safe to look at.

And finally, if you do not have solar shield glasses, Number 14 Welders’ Glass, binoculars, or a telescope (again, projected onto paper!), you still have another option. You can use a colander, a piece of aluminium foil with a hole punched in it, or even with the aid of a leafy tree. Obviously, if you took a colander outside on a sunny day, let the sunlight shine through it, and reflect onto the ground, you would see the circular dots of light where it was allowed to pass through the holes in the colander, and shade where the solid part of the colander blocked it. If you happen to do this when the Sun doesn’t appear as a solid circular light source (an eclipse), or if something is passing in front of it (a transit), the light in those dots on the ground will show it as well.

Check it out!:

Partial eclipse viewed with the aid of a colander.

(Image Source)

This same effect will work if you poke some holes in aluminium foil, a pizza box, or whatever you might have available. Luckily, you’ll have a bit of time during the eclipse to experiment and see what works best.

Even trees want you to see the eclipse:

The Eclipse Tree, Basildon.

(Image Credit: Picture Esk on Flickr)

So that about covers it. If you have any questions, if I’ve missed anything, or if you believe there is a mistake in my explanations, please leave a comment. I hope you’ll take the opportunity to enjoy this celestial treat and I hope you find people to share the experience with you as well.

Happy observing!

With The Supermoon Behind Us

Supermoon sinking into the atmosphere.
(International Space Station crewmember, André Kuipers, snapped this photo of the Supermoon sinking behind the Earth’s atmosphere.)
[Image credit: André Kuipers]

Did you get a chance to see this year’s “Supermoon“? Still confused as to what was so super about it, anyhow? Simply, the supermoon is the colloquial name for what is scientifically referred to as the perigee-syzygy moon. “The … what”, you ask? Don’t worry, it’s not as complicated as it sounds. The Moon orbits our Earth, not in a perfect circle, but in an ellipse. As a consequence of this, there are times the Moon is closer to the Earth and times it is further away. For any object orbiting the Earth, the part of its orbit that takes it furthest from our planet is called apogee. The closest point, perigee.

So now that we have perigee out of the way, “what was that other funny word again?” A syzygy,  (pronounced, Sizz-ih-gee), is a term used to refer to an astronomical event in which 3 celestial bodies form a straight line. In our case with the Moon, the bodies are the Sun, the Earth, and the Moon. You’re probably realizing that the Sun-Earth-Moon system experiences two syzygies each month; we call them the New Moon and the Full Moon.  The lunar month (29.53059 days) is defined as the period of time between two identical syzygies (Full Moon-to-Full Moon / New Moon-to-New Moon).

Putting it all together now: a perigee-syzygy Moon is the Full Moon or New Moon which coincides with its closest approach to Earth. Keep in mind, a New Moon at perigee could also be referred to as a supermoon; however, it’s unlikely to generate much attention because we can’t see the New Moon from Earth. “Well, of course. That makes sense!

So now that we know what a supermoon perigee-syzygy Moon is, let’s talk about what a perigee-syzygy Moon does; or, more importantly, doesn’t do. There is no correlation between perigee and major earthquake activity. There is certainly no correlation between perigee and human behaviour (well, except for the fact that when people start talking about supermoons, more people are likely to take a look at the Moon on that occasion). “But what about bigger tides?” Well, yes! Tides are greatest during Full and New Moons, and there is an increase in the tides when the Moon is closer to the Earth as well. Luckily, tidal forces are weak and even the few percent increase due to the perigee-syzygy isn’t going to create anything that will cause alarm.

But I heard the supermoon is super big and super bright!” While the perigee-syzygy Full Moon is what we can call the biggest and brightest Moon of the year, it’s such a small degree bigger and brighter that its really not noticeable. In fact, last night’s supermoon was only about 1% bigger/brighter than last month’s Full Moon. It did appear 14% larger than the smallest Moon of the year, but again, you’d have to be using some tools other than just your eyes to notice the difference.

An image showing the difference between perigee and apogee Full Moons.
(This image shows the difference in apparent size between a Full Moon at perigee and a Full Moon at apogee. Lined up next to each other, the difference looks quite large. In the sky by themselves, you’d be hard-pressed to notice the difference.)
[Image credit: Copyright © 2001-2012, Anthony Ayiomamitis]

Now, I purposely waited until after the Supermoon had passed to offer this explanation. Why? Because I didn’t want to discourage people from thinking they might see something special if they looked up at the Full Moon last night. It wasn’t easy to stay quiet for a couple of reasons. First of all, all of the ridiculous claims and fear that is generally associated with this event is hard to ignore — and in cases where real fear was involved, I did explain how there was nothing to worry about. The other reason it was difficult to not publish this before the event was that I didn’t want to entirely erase the hype that inevitably surrounds the “Supermoon”. Call it selfish, but I wanted people looking up at the sky last night — even if it was under some slight false pretenses. I want people looking up every night, and if some buzz on the internet can help make that happen, well then… good.

The truth is, the Moon is amazing whenever you can see it. The light of a Full Moon creates amazing shadows on our planet, and is a comforting companion to have overhead at night. Waxing and waning Moons are also beautiful, because they occur at an angle with the Sun in which the shadows and craters are much more pronounced.  And a New Moon (one we cannot see) offers us the darkest skies to observe the other billions of fascinating objects that are just above our heads.  All of which are… well… Super.

An Apollo 9 Anniversary

On this day in 1969, Commander Jim McDivitt, Command Module Pilot David Scott, and Lunar Module Pilot Rusty Schweickart blasted off from Kennedy Space Center for the 10-day Apollo 9 mission. Apollo 9 was the third manned-mission of the Apollo Program and tested many components critical for lunar landing that would occur two missions later with Apollo 11.

Just over four decades later and on the anniversary of its lift-off from Earth, I happen to find myself in San Diego, California where the Apollo 9 Command Module (nicknamed “Gumdrop” by its crew) is displayed at the San Diego Air and Space Museum. I was thrilled to take my family to pay tribute to such an important part of the world’s space program.

The first thing that jumps out at you when seeing an Apollo Command Module for the first time is its size; specifically, how small it is, considering three grown men spent most of their mission living in it.

Apollo 9 Command Module "Gumdrop" and Me

"Gumdrop" and yours truly.

But things really seem small when you take a look inside:

Interior of Apollo 9 Command Module "Gumdrop"

Interior view of "Gumdrop"

The interior offers what appears to be even less room than you have flying coach on a commercial airliner. My legs start to feel cramped after just looking at this picture, so I can only imagine what it must have felt like to spend days in there. I’m guessing that when NASA was recruiting its astronauts, claustrophobia was a disqualifier.

View of some of Gumdrop's controls

Detail of just a few of the seemingly-infinite number of switches and controls.

I spent a lot of time observing the intricate details on the exterior of the capsule as well. The capsule looks exactly how you’d expect, for something that had to withstand temperatures of a couple of hundred degrees below zero (F) on the low end, all the way up to 5,000-degrees (F) on the high end. And that’s to say nothing about the other forces involved in launch, orbit, and reentry.

Detail of "Gumdrop's" Roll Engines

Detail of "Gumdrop's" Roll Engines

The capsule’s heat shield was made of an ablative material — meaning it “turns white hot, chars, and then melts away” during reentry. Amazingly, this heat shield was only two inches at its thickest point, and a mere half inch in some spots! It must have provided quite a light-show for anyone watching the intimidating, yet intended, fiery break-away of the heat shield.

Exterior detail of "Gumdrop"

Exterior detail of "Gumdrop".

To top off the exhibit, there were many other displays related to, not only Apollo 9, but other NASA manned spaceflight programs as well, which I’ll save for another time.

My only gripes about the display were that I wished there were more items and information (though, I could probably never be satisfied in this regard) and more thought put into the ambiance of the displays (for example, rather than controlled lighting, many of the exhibits were lit by very large windows which created a lot of glare that was difficult to see through on some of the displays). Also, I was sort of hoping there would have been some sort of special recognition of today being Apollo 9’s lift-off anniversary since that mission is the focus of one of their major exhibits; but now I’m just being picky.

All said and done, spending a few hours up close and personal with Gumdrop and the associated displays was a wonderful way to celebrate the anniversary of the lift-off of Apollo 9.

Apollo 9 Mission Insignia

Apollo 9 Mission Insignia

Majestic Conjunction

Have you seen the wondrous show that’s been taking place in the night sky recently? Maybe you noticed what appeared to be some especially bright stars, glittering near a crescent Moon. Perhaps you haven’t been looking up at the night sky lately (shame on you) or conditions have been too cloudy to give it a look (I live in a coastal city in Alaska, I feel your pain). Whether you’re looking or not, there’s a fantastic conjunction taking place, starring (pardon the pun!) the Moon, Jupiter, and Venus.

I took the following photo shortly after sunset on February 28, 2012, from within Joshua Tree National Park. Unfortunately, I didn’t have a lens to give me a wider field of view, but the top of a Yucca Plant provides a nice touch.
Moon, Jupiter, and Venus conjunction, labeled.

[Click image for larger and unlabeled version / Credit: Ryan Marquis/46BLYZ]

This cosmic spectacle will continue over the next few days, so get out and enjoy it while you can.

Also in the night sky this month:
While the Moon will have moved away from the planets, Venus and Jupiter will be within three degrees of each other on March 12. That’s approximately the same “width” as three fingertips held at arm’s length… The planets will appear quite close to one another!

Mars also refuses to be left out of this month’s planetary attention. Look for the red planet in the Eastern sky, just a few hours after the sun sets.

Clear skies!

Tortoises In Space: An Homage to Shelled Explorers

Tortoises In Space
Now that I have your attention…

When you think of animals that have been sent to space, what comes to mind? Humans of course, but maybe you also remember the first “higher primate” in space1, Ham the Chimpanzee (or Enos, the first primate to orbit the Earth). Or perhaps the dog Laika — the first animal to orbit the Earth2 — comes to mind. And of course, we’ve sent mice and insects and other organisms into space in the name of research as well.

What probably doesn’t immediately come to mind, however, are tortoises. But tortoises were exactly what the Soviets decided should be among the first animals to circle the Moon.

The Soviet’s Zond (translated: probe) program consisted of two distinct objectives. The first missions, Zond 1, 2, and 3, utilized the 3MV3 planetary probe and were designed to explore Mars and Venus. Zond 1 and 2 failed en route to their respective objective targets, while Zond 3 captured photos from the far side of the Moon on its way out on a Mars trajectory, though the timing wasn’t such that it would encounter the red planet.

Zond 5 Tortoises

Zond 5 Tortoises. Credit: RKK Energia.

Fueled by the “Moon race” between the United States and the Soviets, the following Zond missions employed the Soyuz 7K-L1 spacecraft and were all focused on the Moon. Zond 4 reached a distance of approximately 300,000km (186,411 miles) from the Earth before returning. Its trajectory took it on a course 180-degrees away from the Moon, and there are conflicting stories as to whether or not the Soviets intentionally sent the spacecraft on that course, or if there was a malfunction. It re-entered Earth’s atmosphere out of the Soviet’s control and was remotely detonated at an altitude of 10-15km (6-9 miles), and a couple of hundred kilometers off of the coast of Africa.

Finally, Zond 5 launched on September 14, 1968. Aimed for the Moon, it contained a biological payload including wine flies, meal worms, plants, bacteria, and… two Russian tortoises. Zond 5 took a circumlunar trajectory, which means it looped around the Moon, but didn’t go into multiple orbits around it. Think of a big, lop-sided, figure-eight, with the Earth within a large loop and the Moon within a smaller one. This is very similar to the emergency trajectory that Apollo 13 took, following the disastrous malfunctions that plagued that craft on its way to the Moon.

Circumlunar trajectory of Apollo 13

The circumlunar trajectory of Apollo 13 - Credit: AndrewBuck

The tortoises spent a week in space before splashing down in the Indian Ocean. The tortoises reportedly lost 10% of their body weight during their trip, but remained active and showed no loss of appetite. These tortoises became among the first Earthly lifeforms to complete a lunar flyby and return safely to Earth, proving it possible, and paving the way for future vertebrates such as Neil Armstrong and Buzz Aldrin.

Scientists examining the Zond 5 tortoises.

Scientists examining the Zond 5 tortoises. - Credit:

Zond 5 wasn’t the end of the line for our half-shelled cosmonaut friends; Zond 7 and Zond 8 each carried multiple tortoises. Tortoises then came out of a 5-year retirement to be sent up again, aboard Soyuz 20 in 1975. This time, they were in for the long-haul, spending a total of 90.5 days in space and consequently breaking the record for the longest amount of time an animal had spent in space. Finally, in February of 2010, the Iranian Space Agency sent up their first biological payload into a sub-orbital flight; aboard were two turtles.4,5

So now you know the story of tortoises in space. From being among the first animals to take a trip around the Moon, to breaking records for time in space, tortoises are very much a part of “animaled” spaceflight. Like all of the others that have made Earth’s space programs successful, I tip my hat to the shelled reptiles for their contributions.

  1. Monkeys had gone into space as early as the late 1940’s, though it wasn’t until 1957 when Laika, the dog, became the first animal to orbit the Earth.
  2. And unfortunately, Laika was the first animal to die in orbit, as well.
  3. Third-generation, Mars/Venus
  4. Yes, I’m aware that there is a difference between tortoises and turtles, but the definitions can actually vary depending on which country you’re from. I haven’t been able to find out the specific species of the Testudine Iran sent to space, so they may or may not be tortoises. To be mentioned in this article, I say close enough!
  5. And apparently, at least 64 people are outraged enough by this that they’ve “Liked” a “Save Turtles From Iran’s Space Program” Facebook page.

GRAIL: Ebb and Flow

Artist's Rendition of Grail Mission

Image credit: NASA/JPL-Caltech

Earlier this month, I gave a minor overview of NASA’s Gravity Recovery And Interior Laboratory (GRAIL) mission. I had mentioned that the two mirror-twin spacecraft that make up the mission were currently — and temporarily — dubbed GRAIL-A and GRAIL-B, with official names coming later in the month. Beginning last October, NASA appealed to elementary students to come up with replacement names for the spacecraft.

Over 11,000 students, from 45 states and several territories, participated in contest, making for stiff competition.

Ultimately, it was the 4th Grade students from Emily Dickinson Elementary school, in Bozeman, Montana, who were chosen as the nationwide winners of the naming competition, with their names of Ebb and Flow. The students arrived at their name by researching what the GRAIL mission was studying and how it worked. They learned how important the Moon is to our lives on Earth, and how the Moon’s gravity causes our high and low tides. They decided on Ebb and Flow, because the names represent both the Moon’s gravity and its effects on our home.

Congratulations Emily Dickinson 4th-Graders! Not only did you come up with great contest-winning names, you came up with names that will forever exist in the historical pages of the world’s exploration of space!

For more about GRAIL, check out these links:

Gravity Recovery And Interior Laboratory | GRAIL

Grail Mission Logo

While many of you were partaking in New Year’s celebrations, engineers and other specialists at NASA were also celebrating; albeit, something a bit different.

NASA launched the twin GRAIL-A/GRAIL-B spacecrafts from Cape Canaveral Air Force Station on September 10, 2011, on a nearly 4-month journey to the Moon. 1(footnote below) On December 31 and January 1, GRAIL-A and GRAIL-B — respectively — completed their journey into lunar orbit.

Artist's Rendition of Grail Mission

Image credit:NASA/JPL-Caltech

At this point in the mission, the mirror-twin GRAIL spacecraft are maneuvering themselves into a flying formation that will place them on a near-polar orbit, 34 miles (55 km) above the Moon’s surface. While the craft are currently completing an orbit approximately every 11.5 hours, over the coming weeks controlled burns will reduce that time to just under 2 hours.

From there, the science begins. In March, GRAIL begins its task of creating a comprehensive and detailed map of the Moon’s gravitational field. This will provide tremendous insights into the internal structure of our natural satellite, from core to crust. It will also reveal the history of the Moon’s episodes of heating and cooling. Understanding this thermal evolution takes us a step closer to fully understanding the Moon’s origin and the processes it undertook over the past 5 billion years, to make it what it is today. This new knowledge will extend our understanding not only of the Moon, but the other rocky inner solar system planets as well.


Grail heading towards the Moon

Photo credit: NASA/Darrell McCall

For the kids; our future.

Both spacecraft contain a camera called GRAIL MoonKAM (Moon Knowledge Acquired by Middle school students). MoonKAM is installed solely for education and public outreach, being led by Sally Ride (the first American woman in space, but of course you knew that) and her Sally Ride Science team. GRAIL MoonKAM is designed to engage middle school-aged students from across the nation. Students will be able to target areas on the surface of the Moon, submit their requests to GRAIL MoonKAM, and then receive photos of the target area to be studied in the classroom.

In addition to GRAIL MoonKAM, beginning in October of last year students were also able to enter a contest to choose new names for the spacecraft. So if the names, GRAIL-A and GRAIL-B aren’t particularly exciting to you, the new names are expected to be revealed later this month.


I’m excited to see what GRAIL reveals about our nearest interplanetary neighbor. The Moon still harbors a number of puzzling mysteries, and there’s a good chance that GRAIL might shed some light onto their answers. GRAIL is a comparatively short mission, expected to conclude around early June of this year; so, our new data and understanding will be coming to us soon. After decommissioning is finished, the GRAIL orbiters will be smashed into the Moon’s surface, in true NASA fashion.

To read more about GRAIL, check out the following links:

GRAIL press kit (.pdf)

MIT’s GRAIL page

Sally Ride Science GRAIL MoonKAM page

NASA mission page

  1. When NASA is sending people to the Moon, we do it in 3 days. It is safer for our astronauts and easier to plan for, but it comes at a month greater fuel cost. With spacecraft such as GRAIL, we can save a few bucks and take our time.

Christmas Eve Earthrise

On Christmas Eve, 1968, one of the most iconic space images of all time was taken. The beautiful Earthrise image was taken by William Anders, aboard Apollo 8 — the first manned mission to the Moon (to orbit, not land).

Photo of Earth Rise from Apollo 8

(Click image for full-sized version / Source: NASA)

The words of Commander Frank Borman, as taken from the transcript of the mission, are quite fitting of what it must have felt like to see such a sight:

“Oh, my God! Look at that picture over there! Here’s the earth coming up. Wow, is that pretty!”