The Top Five Greatest Moments in US Spaceflight

To celebrate the Fourth of July, I wanted to cover the top five greatest moments in US spaceflight. Whether you love or hate the country, no one can doubt its historical importance, especially in the out-of-this-world arena of spaceflight. Before we dive into this top five, you have to understand that this is a PERSONAL ranking. Your top five greatest US spaceflight moments might differ from mine.

With that preposition out of the way, let's go into the ranking!

#5 Opportunity Rover

Of course, we had to talk about the little rover that could. Opportunity and her twin rover, Spirit were meant to last just 90 days on the Martian planet. However, Oppy would go on to defy all odds and explore the red world for 14 years. Her older twin, Spirit lasted less than half of that time, at just over 6 years. These rovers would cement themselves as legends, in both the science community and pop culture. Many remember this Martian explorer for "saying" the famous, "My batteries are low, and it's getting dark" line. While this wasn't exactly what the rover said, it captured the hearts of millions. After the last contact was made, teams at NASA attempted to wake up the rover for over 200 Earth days. Sadly, they never heard back from Oppy and the mission was finally declared over in February of 2019. Here are some of her accomplishments over her 14-year odyssey:

✦ Discovered signs of ancient flowing water on the planet.

✦ Studied how craters form and erode over time.

✦ Studied Mars's atmosphere (clouds/dust) for over a decade.

On Mars, the rover pair took hundreds of thousands of photos and Oppy traveled some 45 kilometers (28 miles). Lasting over 60x more than expected, Opportunity helped humanity better understand one of the most enticing celestial bodies in the solar system.

Honestly, the United States is an obvious leader in Mars exploration. With a plethora of landers, rovers, and orbiters being sent to the Martian system. Ingenuity is another huge resounding success from the United States, seeing the first powered flight on another planet. The InSight lander, as well as the Curiosity and Perseverance rover, have also provided amazing looks into our celestial neighbor. The Mars program has been an amazing part of the US space industry and one that will only grow from here on out!

#4 Hubble Space Telescope

Next, we have the Hubble Space Telescope (HST). If you follow the world of spaceflight/exploration, you have undoubtedly heard of this telescope. Hubble was not the first space telescope ever, however, it is by far the most famous. Many deep space images shared around the web likely originate from this telescope. Not limited by the distorting atmosphere and pesky light pollution, Hubble was genuinely the first time humanity was able to look deep into the Universe.

Since its launch in 1990 onboard Space Shuttle Discovery, Hubble has been peering into the cosmos. Many may know that it wasn't all sunshine and rainbows in the beginning though. A mirror misalignment caused the first Hubble images to be blurry and fuzzy. The problem was so bad, that NASA had to launch servicing missions to the orbital telescope using the Shuttle. In all, Hubble was serviced, modified, and boosted five times. These missions greatly expanded the life and capabilities of Hubble and made way for an immense amount of discoveries. Here are just a few of the Hubble Space Telescope's biggest impacts:

✦ Helped Scientists determine a rough age for the Universe (~13.8 billion).

✦ Data from Hubble has been used in over 21,000 published scientific papers.

✦ The orbiting space telescope has made some 1.6 million discoveries since its mission started in 1990.

Because Hubble hasn't been serviced since 2009, the telescope's orbit has been slowly decaying, and hardware on the orbital observatory has started to show its age. While there have been talks to service the space telescope with SpaceX's Crew Dragon, no mission has been set. We sadly may be approaching the end of one of the greatest scientific pieces of hardware, ever. Regardless, Hubble has truly been one of the United State's bests technological feats.

#3 Voyager 1 and 2

The twin spacecraft of Voyager 1 and Voyager 2 are truly icons of humanity's emerging space age. The name "voyager" alone is so indicative of the importance of these two probes. Launched just weeks apart in 1977, the two Voyagers have gone on an interstellar odyssey. You may be surprised to hear it, but since Voyager 2 made the first flyby of Uranus in 1986 and Neptune in 1989, no other spacecraft, from any nation has ever revisited these ice giants. While Pioneer was first to the Jovian and Saturn systems, Voyager was the first to reach the outermost planets, as well as every single gas and ice giant.

Voyager 2 being the first (and only) probe to give us closeup views and data on the planets of Uranus and Neptune is great enough to put it on this ranking in of itself. But, it doesn't stop there. While Voyager 2 was busy studying all of the outermost planets, Voyager 1 was FLYING towards the edge of our solar system. After making its flyby of Saturn, Voyager 1 used a gravity assist to help push itself further away from the Sun. And after 35 years of traveling, Voyager finally broke beyond the heliopause and made it to interstellar space in 2012. Between the two probes, so much was uncovered. Below are some of the greatest achievements of these two cosmic voyagers:

✦ Discovered that all the gas/ice giants had rings and also discovered 24 moons!

✦ Data from Voyager 1 and 2 hinted at a potential sub-surface ocean on Europa, as well as Volcanic activity on IO and a nitrogen rich atmosphere on Titan!

✦ Is an interstellar "time capsule" of sorts with the Golden Record plaque on both probes, with information about Earth, humanity and our knowledge of the universe.

✦ First humanmade object to reach interstellar space!

✦ Took one of the most breathtaking images ever (Pale Blue Dot)

Sadly, despite breaking out of the interstellar medium, little is known about this region just beyond our star. This is due to the age of Voyager, its RTG, which is essentially a little nuclear reactor using plutonium, has decayed to the point it is outputting far less energy than required. This means a lot of the scientific instruments have been shut down, with a bulk of the power used to communicate with scientists back on Earth. The Voyager probes were willed into existence by the United States and the science community should be so incredibly thankful they were. Truly a once in a lifetime mission that pushed the envelope in all regards.

#2 Reusable Rockets

From the Space Shuttle to Falcon 9 the United States has truly paved the way in the reuse of rockets. This is an insanely important next step that will allow for more, cost-effective missions to new worlds. While you may think this is placed pretty high at number two, this is just the beginning of humanity's shared effort to make affordable ways to go further into the cosmos.

While many may argue that the Space Shuttle wasn't reusable and more "refurbish-able" its design was based on the idea of cost-effectiveness. While the cadence and cost goals were never obtained, it was a great effort to try and reduce the price tag on space missions. The Space Shuttle is also an insanely important part of US spaceflight. The Shuttle enabled Hubble servicing missions and helped with the construction of the ISS, among other things.

The real star here, however, is undoubtedly SpaceX's Falcon 9. It is a rocket like no other, with absurd cost effectiveness the Shuttle could only dream of. Its high cadence and reuse have reduced the cost per kg immensely. For the Space Shuttle, the cost per kilogram was around $54,000. Falcon 9 has an estimated cost per kg of just $2,720. It truly is only becoming more and more easy to access the cosmos, which allows for more science and discovery. Here are some reasons why reusable rockets are such an incredible piece of tech, pioneered by the US:

✦ Far lower cost per kilogram, allowing for better accessibility to space.

✦ Doesn't waste as much hardware

✦ Partially reusable rockets are paving the way for fully reusable ones, which will only drop the costs further.

The best part about reusable rockets? This is just the very beginning of it all. SpaceX has had such a positive impact on the launch provider industry, that we are seeing a true "reusable rocket" wave, with more and more partial/fully reusable rockets in development than ever before.

Honorable Mentions

Of course, no top-five list is complete without some honorable mentions. While these are placed in no real order, these are also other amazing achievements from the United States that deserve to be mentioned!

New Horizons

Before New Horizons flew by Pluto in 2015, we knew very little of this infamous dwarf planet. Such a historic mission deserves some recognition. The New Horizon flyby of Pluto uncovered the last major celestial body in our solar system. New Horizon also flew by the Kuiper Belt Object Arrokoth another first for the spacecraft.

Pioneer 10

This is one of the most underrated robotic spaceflight missions ever. Pioneer 10 was the first space mission to: be sent on a trajectory away from the sun, cross the asteroid belt, and leave the inner solar system, and finally, it was the first flyby of Jupiter. This was humanity's first step into the outer solar system and it helped unmask a ton of information, particularly about Jupiter's atmosphere and magnetic field.

James Webb Space Telescope

While JWST is the direct predecessor to Hubble, it didn't make the list as it still has a long road ahead of itself. JWST is an amazing piece of technology that has taken insane images, but this is just the tip of the iceberg. As the Webb telescope continues its journey through the cosmos, it will cement itself as a legendary scientific tool. Webb will also play a crucial role in better understanding the atmospheric composition of exoplanets. This is crucial as we try to find hotspots for potential extra-terrestrial life.

#1 Man on the Moon

This is probably no surprise, but of course, the first (and only) nation to send humans to another celestial body would be the greatest moment in all of the United State's spaceflight history. As it stands, no one compares, quite literally. That will change in the coming decade(s) with the likes of the Artemis Accords and the International Lunar Research Station (ILRS). However, no matter the space fairing future man is heading towards, it will always be cemented as an American first, to land humans on a new world. Apollo saw 12 men over six missions land on the surface of the Moon. Here are some of the amazing discoveries/moments from the Apollo program:

✦ Apollo 11 was the first mission to collect and retrieve samples from the Lunar surface. Over the course of all Apollo surface missions, 382 kilograms (842lbs) of Lunar samples were collected.

✦ The oldest Moon rocks are older than the oldest rocks on Earth. This is due to the fact that conditions on Earth are constantly changing due to geological activity.

✦ The Moon once had an ocean of magma on its surface.

And by far the biggest and most important discovery of the Apollo program was that of Earth. As astronauts looked back at home, at a distance unfathomable just years before, we could finally take in the absurdity of our existence. A blue dot in a vast sea of darkness. Life never looked more brilliant nor as fragile. In the words of Astronaut William Anders....

We came all this way to explore the moon, and the most important thing is that we discovered the Earth."