When the Wright Brothers first took off in their flying machine over a century ago,
they never could have imagined how ubiquitous air travel would become.
Approximately 100,000 flights take off and land around the world each day,
with ticket prices getting cheaper and cheaper as the industry develops.
After mankind had conquered the skies and made air travel a trivial affair,
we looked towards the next frontier: space. But as engineers design new types of spacecraft,
some might wonder why they go to all the trouble. After all, planes can fly pretty high. Couldn't
we just fly them a little bit higher? Say...all the way into space? Technically the answer is no,
we absolutely couldn't. But why? That answer is a little bit more complicated.
Let's first look at how high planes can actually go. Commercial jets tend to fly
at an altitude of around 28,000 to 35,000 feet, but they can reach heights of up to
40,000! Most of them aren't meant to go much higher than that, though there are exceptions,
such as the Concorde, a supersonic commercial jet that could reach a cruising altitude of
60,000 feet. NASA also designed an airplane called Helios that was able to fly up to 97,000 feet,
but it was powered by electric motors and didn't resemble a typical airplane. Meanwhile,
the minimum height required to exit the Earth’s atmosphere and enter orbital space is 62 miles or
327,360 feet. That's nearly ten times the average height most commercial jets tend to fly at.
So commercial planes and some scientific prototypes can't fly high enough to make
it into space, but what's the reason for that? Why can't you just hop on a plane
at LAX with a dream in your heart and soar off into the great unknown? Well,
there are a few different reasons for that. First, there are the forces that act on a plane: lift,
weight, thrust and drag. Planes are designed with these forces in mind, and they are an essential
factor in a successful flight. But in space, the gravitational force and air resistance ordinarily
present are gone, and the forces required for the plane to act as intended are gone, too.
Next, there is the matter of temperature. Re-entering the Earth's atmosphere generates a
great deal of heat. Space shuttles are equipped with protective shielding that allows them to
endure this heat without falling apart, but planes aren't quite so resilient. Even if you were able
to fly a plane into space successfully, reentering the atmosphere would roast any passengers unlucky
enough to be inside. Don't pay for an economy ticket to space, folks. It's just not worth it.
Another obstacle standing between an ordinary commercial plane and space travel is the quality
of air closer to space. The higher you go, the thinner the air becomes. At a high enough
altitude, the air becomes too thin for the plane to maintain its lift. At this point, the
plane reaches something ominously called a "Coffin Corner," in which it can no longer speed up, slow
down, or climb any higher. The only way to keep the aircraft from crashing once a Coffin Corner
occurs is by reducing its altitude while carefully gaining speed during a controlled descent.
And then, there's the issue of the plane's engine. Commercial airplane engines are
unable to generate enough thrust to propel a craft through the atmosphere and into space,
which requires approximately 7.2 million pounds of thrust. For comparison,
the Boeing 747's engine generates around 63,000 pounds of thrust. Airplane engines also rely on
air in order to generate combustion. Without enough fresh air, that combustion ceases,
and the engines die. Turns out the "air" part of "airplane" matters quite a bit. This would pose
a pretty big problem in space, given that it's pretty famous for being a place without much air.
So what would happen if a pilot decided to try their luck and fly their plane
into space anyway? Well, like the Greek myth of Icarus, in which the titular young
man disobeyed his father and attempted to fly higher and higher using a pair of wax wings,
only to have them melt from the heat of the sun, they would suffer a terrible fall back to Earth.
Surprisingly this has actually happened, with the most prominent example being the
Pinnacle Airlines Flight 3701 in 2004. On October 14, 2004,
Flight 3701 was due to transport an empty 50-seat Bombardier CRJ200 from Little Rock, Arkansas,
to Minneapolis. The planned cruising altitude for the fight was 33,000 feet, but shortly after the
plane left its destination, it began to ascend rapidly. After only 14 minutes of flight, the
pilots requested clearance to cimb to 41,000 feet, the maximum operating altitude for the Bombardier
CRJ series. They expressed to each other an eagerness to test the limits of the aircraft.
Clearance was granted, and the plane quickly climbed to this ambitious new
height. Once it did, however, disaster struck. Both of the engines lost power,
likely due to the sudden ascent to an altitude at the absolute limit of the
craft's capabilities. The pilots declared an emergency and descended, but were unable to
restart the engines. The flight crashed into the ground outside of Jefferson City, and both crew
members were killed. The National Transportation Safety Board listed the causes of the crash as,
quote, “The pilots' unprofessional behavior, deviation from standard operating procedures,
and poor airmanship.” Which seems a little harsh, given that they were already dead.
If the pilots’ goals was to get to space well, lets just say they didn’t get close.
Only reaching 41,000 feet, they were just over 12% of the way to escaping our atmosphere.
So, we know that airplanes can't fly into space, but there actually is a type of
plane that can. That's right, you guessed it: spaceplanes. A spaceplane is a vehicle
capable of flying and gliding like an aircraft while in Earth's atmosphere,
and moving like a spacecraft once it's exited the atmosphere into outer space. It's sort of
the best of both worlds. There are four types of spaceplanes that have successfully launched
into orbit, reentered the Earth's atmosphere, and landed safely: The U.S. Space Shuttle,
the Russian Buran, the U.S. X-37, and the Chinese CSSHQ, or Reusable Experimental Spacecraft.
The Space Shuttle was a partially reusable NASA spacecraft system that was operated from 1981
to 2011. Its components included the Orbiter Vehicle, which served as the spaceplane, three
rocket engines, a pair of solid rocket boosters, and an expendable external tank. The Space Shuttle
launched vertically like a typical rocket. The solid rocket boosters would be jettisoned from
the craft before reaching orbit, as the main engines continued powering it. Then, after the
main engine cutoff and as the craft prepared to enter a steady orbit, the external tank was
jettisoned as well. When it was time for the craft to reenter the atmosphere, its thermal protection
system kept it safe from high temperatures, and then it executed a runway landing as a spaceplane.
In response to the NASA Space Shuttle, the Soviet Union started the Buran program.
Buran-class spacecrafts were similar to the Space Shuttle, but there were some notable
differences in design. The main engines did not follow the spacecraft into orbit. Instead,
small rocket engines on the body of the craft helped to propel it in orbit. It
was also capable of fully automated landings, and flying missions without a crew on board.
The Boeing X-37, also called the Orbital Test Vehicle,
is a more modern spaceplane that was first used in 2010. It’s made up of a
reusable robotic craft that is carried into space by a rocket-powered launch vehicle,
where it remains in orbit to aid in exploration and research. Once it’s time for the X-37 to land,
it will reenter the atmosphere and glide back to the ground as a spaceplane.
The CSSHQ is China’s answer to this new spaceplane arms race. It’s a reusable orbiting spacecraft,
first launched in September 2020, that operates similarly to the other
orbiting spaceplanes we’ve discussed so far. If it ain’t broke don’t fix it.
In addition to these orbiting spaceplanes, there have been two rocket-powered aircrafts
that have crossed the internationally recognized boundary into space: the X-15 and SpaceShipOne.
On July 19, 1963, American World War II Pilot, physicist, and astronaut Joseph A. Walker flew
NASA's X-15 in the now-famous Flight 90. During this flight, the craft reached an
altitude of 106.01 kilometers, crossing the Karman Line and entering space. While up there,
the interior of the craft achieved weightlessness for between 3 and 5
minutes. As it reentered the atmosphere, some portions of the craft's exterior heated up to
650 degrees Celsius. This historic flight only lasted twelve minutes from launch to landing.
SpaceShipOne took flight many decades later, in 2004, as part of the competition for the
10 million dollar Ansari X Prize. The challenge was as simple to describe as it was difficult to
achieve: be the first private organization to complete two successful piloted flights
with two passengers in two weeks. Oh, and both of those flights needed to cross the
boundary of space. This was achieved through several innovations working together. First,
there was the launch aircraft, a hybrid rocket engine system named White Knight.
This carried SpaceShipOne to a height of 47,000 feet, then dropped it. At this point,
the pilot lit the craft’s hybrid rocket, sending SS1 shooting up toward its goal.
Another element of SS1 that allowed it to successfully complete its journey was the
"feather" system. The feather here refers to the rear portion of SS1's wings, which
would fold vertically before the craft reached its highest point. This would increase drag,
slowing SS1's speed as it prepared to reenter the atmosphere. Then, the feather would be retracted,
allowing the craft to glide to a smooth, safe landing. After a series of test flights,
each creeping closer and closer to space, pilot Mike Melvill made hisotry on June 21,
2004, when he passed the boundary of space by 150 meters.
How did he celebrate this momentous occasion? He spent his few moments of weightlessness at
the top of the world releasing chocolate into the cabin. How's that for a sweet victory?
SpaceShipOne continued to prove itself with more and more flights into space,
and today, it’s prominently and proudly displayed
at the Smithsonian Institution's National Air and Space Museum in Washington, DC.
In the decades since the first launch of the Space Shuttle, there have been few official
developments in the world of spaceplanes capable of entering orbit. The Boeing X-37B is the only
craft still frequently used today, and pales in comparison to its predecessors such as the
Space Shuttle. So, why aren't there more spaceplanes rocketing off into the sky?
Well, there are researchers trying to bring the reusable spaceplane back. Reaction Engines,
a British aerospace company founded by three engineers following the cancellation of a British
spaceplane project in 1989, intends to create Skylon, a single-stage to-orbit spaceplane.
They're also designing an engine to power it. The Synergetic Air-Breathing Rocket Engine,
or "Sabre," is a hydrogen-powered engine intended to use the oxygen
in the Earth's atmosphere to propel a spaceplane to hypersonic speeds before
blasting off into space much in the style of a conventional rocket. There are some pretty
impressive names attached to this project, such as Rolls-Royce, Boeing, and British Aerospace.
So when can we expect to see Skylon in action? In April of this year, Reaction Engines CEO Mark
Thomas spoke about the project on the Aviation Xtended podcast, saying: "What's more likely is a
two-stage-to-orbit system, so you'd still have a very capable and fully reusable first-stage
launcher that could well operate in a horizontal take-off and landing configuration, but you'd have
a more an expendable, or less reusable, upper stage that did the ultimate push to orbit."
So, okay, the future of aerospace technology is cool and all, but what about the non-astronauts
who want to take a spin on a spaceplane while watching old NBC sitcoms and eating potato chips
in an uncomfortably stiff chair? Will spaceplane travel ever come to the regular joe consumer?
Well, as it turns out, the first commercial space flights have already happened! British business
magnate Richard Branson's Virgin Galactic, a spaceflight company aiming to usher in a new
era of space-based tourism, completed its first commercial flight into space on June 29, 2023.
This maiden voyage aboard the rocket plane Unity included an instructor,
the plane's two pilots, two Italian Air Force colonels, and an aerospace engineer
from the National Research Council of Italy. The suborbital ride lasted
just 90 minutes, and as they experienced a few minutes of weightlessness at the highest point,
the passengers unfolded an Italian flag in celebration. The first guests on Virgin
Galactic were there as scientists just as much as tourists, one of them wearing a suit
that measured his biometric data throughout the journey. Another conducted an experiment
concerning the mixing properties of different liquids and solids in a low-gravity environment.
There were some concerns about the safety of the trip following the deadly crash of
Virgin Galactic's SpaceShipTwo in 2014, and the disappointing results of Virgin Orbit's satellite
launch, which ended abruptly when a rocket carrying the first-ever satellites to launch from
British soil failed to make it to orbit. However, the flight went smoothly, and people began
clamoring to be on the next trip to space. At the time of this first flight, the company had sold
800 tickets for future trips. Before you reach for your wallet, though, you should know that the
price is a little steep for the average space enthusiast, clocking in at around $450,000 a
seat. Sorry folks, unless you’re part of the 1%, commercial space travel is still a no go.
Okay, that's not exactly true. You could also be lucky enough to win a fundraising
competition by the organization Space for Humanity, a non-profit intending
to make space travel more accessible. That's what happened to Keisha Schahaff,
who won a spot aboard the first Virgin Galactic flight for space tourists rather
than passengers with professional experience. Schahaff, her daughter, and former Olympian
Jon Goodwin climbed aboard the Unity in August of 2023, along with the spaceplane's commander,
the pilot, as well as Virgin Galactic's Chief Astronaut Instructor, Beth Moses.
The Unity spaceplane was strapped to the wing of a Virgin twin-fuselage VMS Eve carrier jet,
which took off from a 12,000-foot runway in the New Mexico desert at
around 11 A.M. Once the carrier jet reached an altitude of approximately 45,000 feet,
it released Unity, dropping it from the wing much like you might drop a
bomb. But the only explosions involved in this vessel were minds being blown.
A few seconds after Unity was dropped, its hybrid rocket motor ignited to propel the
craft upward and out of the lower atmosphere. Its velocity steadily increased until it was
around three times the speed of sound, and then the rocket motor shut down,
suspending the crew and passengers in a few minutes of weightlessness. It continued to
climb upward until it reached its maximum altitude of 54.9 miles. During the descent,
while still weightless, the passengers were able to remove their straps and float freely through
the cabin. Then, once everyone was safely back in place, Unity feathered its wings,
increasing drag to slow its descent, and began to make its way back to Earth. Once back in the
atmosphere, it rotated its wings back into their original place and glided back onto the runway.
As impressive as the experience onboard a Virgin Galactic spaceplane might be,
the voyage is strictly suborbital. Is there any hope for a commercial spaceplane that actually
enters orbit like the Space Shuttle? Sierra Space is developing one, the Dream Chaser,
a winged commercial spaceplane ideal for transporting cargo or even human
passengers. Eventually, it could carry up to seven people, as well as cargo,
back and forth from a point in low Earth orbit. The cargo version of the Dream Chaser is intended
to resupply the International Space Station, as well as transport cargo back to Earth from the
ISS if necessary. For now, this version is being prioritized over the passenger-friendly version.
But they're not stopping there. Sierra Space is aiming even higher than a winged spaceplane
capable of transporting people to the ISS. They're also developing the LIFE habitat.
Not the cereal, or the board game, but the Large Integrated Flexible Environment habitat,
a structure that launches via a rocket and, once in orbit,
inflates to a height of three stories and a diameter of 27 feet. It'll likely be a while
before it's ready, but the plans for this mobile habitat and workspace are ambitious.
As the Sierra Space website puts it, "Remote work will never be the same." They're promising three
floors of living and working area, able to accommodate crews of between 4 and 12 people,
life support systems that regulate the air pressure, humidity, temperature,
and oxygen levels, a multi-layer shield able to withstand the harsh conditions of space,
and an Astro Garden able to grow fresh plants and produce. That's quite a lot to accomplish,
but they've already built a ground prototype,
so who knows? Maybe sometime soon, working from home will expand to include "working from space."
This is as far as current technology will allow us to go when it comes to
planes that can carry passengers into space. But here's another question:
once you've hopped on that spaceplane, where are you taking it? What's the destination? Sure,
maybe it's just "space, in general," but why stop there? Once we've taken planes into space,
why not bring other aspects of flying along, too? Such as the airport itself, with its various
shops, eateries, and the oh-so-exclusive airport lounge? They're working on that,
too. Enter the Orbital Reef. Well, you can't enter it because it doesn't exist yet. But it's intended
to be a "Mixed-Use Business Park in Space," and "The First Commercially Owned and Operated Space
Station," a station in low Earth orbit centered around commerce, research, and space tourism.
The Orbital Reef promises to include the LIFE habitat as well as the Dream
Chaser spaceplane in its operations. It also promises a variety of uses and experiences,
from business, to a spacious research laboratory for physical, biological,
or Earth science as well as product development, to pure tourism and curiosity about the experience
of space. They intend for the Orbital Reef to be made a reality by the decade. It sounds like
something out of a science fiction story, but in August 2022, Orbital Reef's plans passed
a System Design Review by NASA. This review, which was conducted from mid-June to mid-July,
served to confirm that the concept for the Orbital Reef met the requirements to function as intended.
Orbital Reef wasn't the only space station concept to pass this review. Starlab station,
a continuously crewed commercial space station being built by Voyager,
passed the review, as well as another commercial space station concept from
Northrop Grumman Corporation. Another company, Axiom Space,
reached an agreement with NASA to add commercial modules to the International Space Station itself.
These will later be formed into a commercial space station if all goes according to plan.
It all seems promising, but the talks of transitioning to commercial space stations
by the close of the decade have not been met with only support. NASA's safety advisors and inspector
general have criticized the short timeline, warning that these commercial stations might
not be ready by the planned deadline. However, representatives from both NASA and the four
companies involved in developing these stations disagree with these concerns. They are all making
great progress, according to them, and Orbital Reef plans to launch its first modules in 2027.
So, while you can’t can’t fly a comercial jet into space, and most people won't be
able to snag a seat on a spaceplane either, as we develop better and better methods of space travel,
it’s entirely possible that a future is coming where ordinary people will be able
to purchase a business class ticket to the stars. Sounds like a blast!
Now go check out “What Crew of Titan Experienced When
Submarine Imploded." Or watch this video instead!