What are the Space Planes of the Future?

October 7. 2018. 8 mins read

The announcement earlier this year that the United States would field a sixth military branch, dubbed Space Force, immediately conjured to mind sci-fi dynasties like Buck Rogers or Battlestar Galactica, where hotshot pilots maneuver sporty-looking spaceships against various alien baddies. Unfortunately, if the Earth was attacked tomorrow by intelligent giant insects flying super-fast ships that wanted to turn the planet into a dust-choked anthill, there’s not much we could do about it. We’re still not that far removed from the sort of clunky rocket technology that took us to the moon. What we really need today are badass space planes. It turns out, we’re not that far from getting them.

Early Space Planes

There is no hard definition of a space plane, but as the name implies, it is a plane capable of flying through outer space or maybe achieving a low-Earth orbit. It combines the features of an ordinary aircraft – meaning the ability to land like an airplane – with the sort of bells and whistles required of a spaceship that operates in the hostile vacuum of space. Bigger brains than are required for an MBA have been developing and building space planes since at least the 1930s, beginning with an Austrian engineer (and, ahem, Nazi) named Eugen Sänger whose work on rocket technology indirectly led to the creation of the American X-15. The X-15 was the first aircraft that passed the so-called Kármán line, the theoretical boundary between Earth’s atmosphere and outer space, pegged at 62 miles above the planet’s surface.

The X-15 space plane.
The X-15 space plane. Credit: NASA

The most famous space plane is the Space Shuttle, which launched vertically like a standard rocket but landed horizontally like any ordinary commercial aircraft. There have been many efforts to develop space planes before and since the 30-year-old Space Shuttle program ended in 2011. For example, back in the 1980s, military and civilian engineers and scientists worked on a new “Orient Express” space plane that could travel 17,000 miles per hour and circle the globe in 90 minutes – briefly popping into outer space – in order to usher in a new era of passenger service. (Just imagine the baggage fees.) Of course, Elon Musk of SpaceX promised much the same thing last year, though sans the space plane concept. (Expect some long flight delays between Twitter tirades.)

Why Space Planes?

Rocket technology – and, really, the entire commercial NewSpace industry – is still too immature to answer the question of whether space planes are economically and technically superior to other types of spacecraft. One obvious argument in favor is that a space plane, like the Space Shuttle, can be used repeatedly for successive missions. Conversely, SpaceX has demonstrated the reusability of its own rocket technology. Its missions are also much cheaper than the Space Shuttle ever was: SpaceX says its Falcon Heavy costs about $62 million per launch versus about $450 million per Space Shuttle mission launch. That doesn’t mean that future space planes can’t operate more cheaply.

Space Shuttle comes in for a landing.
Space Shuttle comes in for a landing. Credit: NASA

Another checkmark in the pro column for space planes is that once the technology matures, they could launch as regularly as any commercial airliner. The ability to launch repeatedly at will means we can tackle any hostile aliens that try to mess with Earth, assuming we’ve also mastered photon torpedoes by then. The more immediate advantage is that a space plane could launch satellites in rapid succession, as numerous startups are planning large constellations of satellites in the near future, especially with an eye toward creating a global internet system that requires hundreds if not thousands of satellites.

Space Planes of the Future

Now that we have a bit of background on the history of space planes and a couple of reasons why they would be really cool to have, let’s look at some of the concepts under consideration, beginning with some hush-hush designs by the government.

Space Plane for Super Secret Missions

The U.S. Air Force’s X-37B space plane, built by Boeing (BA), is more than just a concept. Its first flight was way back in 2010, and it may be orbiting above us right now (last spotted over the Netherlands in August) on its latest clandestine mission that will no doubt fuel conspiracy theories of imminent attacks by bug-eyed aliens. The robotic space plane was launched by a SpaceX Falcon 9 in September 2017, so it’s been up there for a year or more. It actually resembles a Space Shuttle mini-me, as it’s small enough to fit inside the Space Shuttle’s cargo bay, but it’s completely autonomous. Check out this awesome graphic from Space.com:

The U.S. Air Force’s X-37B space plane may be hunting for satellites to destroy.
The U.S. Air Force’s X-37B space plane may be hunting for satellites to destroy. Credit: Space.com

While the U.S. Air Force says the plane is a test bed for future space-based technologies, some have speculated that it is some sort of future space-based weapon for destroying satellites. Apparently, the FCC is taking the net neutrality fight to outer space.

Not to be out-spied, China is reportedly developing its own version of the Air Force X-37B, in its typical tit-for-tat with the United States in everything from artificial intelligence hardware to its own Chinese NewSpace industry. And not to be left out, the Russians are also supposed to be working on some sort of space plane bomber or fighter … or something.

Space Plane for Satellite Deployment

The X-37 program started with NASA but was eventually passed on to our favorite shadowy government agency, DARPA, which is hard at work on a new experimental space plane with Boeing. The XS-1 program envisions a fully reusable autonomous space plane about the size of a business jet that could fly at Mach 10 (ten times the speed of sound). It would lift off vertically but be powered solely by self-contained cryogenic propellants, meaning no external boosters like the Space Shuttle. Its main purpose would be to deliver satellites into orbit, then land back on Earth like any other business jet in time for cocktail hour.

A new concept space plane from DARPA.
A new concept space plane from DARPA.

Dubbed the Phantom Express, the XS-1 program is currently caught up in a legal battle with Space Ghost over his Phantom Cruiser trademark.

Space Plane for Tourism

Space tourismClick for company website is expected to be one of the key industries in the future trillion-dollar NewSpace economy. At the forefront is Virgin Galactic, a private company founded by Sir Richard Branson and some exceedingly less interesting stiff-suited types. While the company has been struggling to get its venture off the ground – culminating in a 2014 accident that killed a test pilot – it has had some recent successes. The space plane, the VSS Unity, completed its third rocket-powered supersonic outing in less than four months in July, reaching Mach 2.4, but still short of the Kármán line. The Unity, like most space planes, is first carried into the Earth’s upper atmosphere by a mother ship that releases the rocket ship.

Virgin Galactic's space plane during a test flight.
Virgin Galactic’s space plane during a test flight. Credit: Virgin Galactic

Branson told Bloomberg following the latest successful test flight that about 800 people have already purchased a $250,000 ticket to ride the ultimate crotch rocket. Virgin Galactic could launch the first tourist flight by the end of the year, but expect the schedule to slip as always, meaning more time for you to raise cash on GoFundMe (to die in spectacular fashion).

World’s Biggest Plane to Launch a Space Plane

Click for company websiteAnother company backed by a billionaire, Stratolaunch Systems was founded in 2011 by Microsoft co-founder Paul G. Allen. The company has built the world’s biggest airplane, with a wingspan of 385 feet and sporting six Boeing 737 engines. The Stratolaunch is not a space plane itself but the platform for launching rockets and other space vehicles, including the company’s concept space plane, dubbed Black Ice.

Stratolaunch has built the world's biggest airplane to launch a space plane.
Stratolaunch has built the world’s biggest airplane to launch a space plane. Credit: Stratolaunch Systems

Stratolaunch is also developing new engines for its medium-lift rocket, as well as Black Ice, capable of 200,000 pounds of thrust. The PGA engine (Allen’s initials) has undergone some preliminary tests so far.

Space Plane for ISS Cargo

Click for company websiteWe were really surprised but delighted to learn that Sierra Nevada Brewing Company was getting into the space race, only to realize that Sierra Nevada Corporation is actually a 55-year-old private aerospace company. NASA had given SNC more than $300 million in contracts to develop early version of its Space Shuttle-like Dream Chaser, with the goal of using the space plane to ferry astronauts to and from the International Space Station. The space agency changed its mind a few years ago and awarded those contracts to rivals SpaceX and Boeing. However, as a consolation prize, NASA has given SNC the green light to carry cargo to the ISS beginning in 2020. It should look something like this:

An illustration of the Dream Chaser docked at the ISS.
An illustration of the Dream Chaser docked at the ISS. Credit: Sierra Nevada Corp.

Dream Chaser has little winglets – about in the same proportion that a T. Rex has arms – so it relies on the lift created by the body of the vehicle, which is wide and flat, to gain altitude. The form gives it a higher lift-to-drag ratio and more landing capability.

Space Planes Capable of Taking Off Like an Airplane

Click for company websiteFounded in 1989, Reaction Engines is a U.K. startup that has raised about $148 million in recent years, including a $37.3 million Series B in April from the likes of aerospace/defense companies Boeing and Britain’s BAE Systems (BAESF), as well as Rolls Royce. Reaction Engines’ claim to fame is the air-breathing rocket engine called SABRE (Synergetic Air-Breathing Rocket Engine). SABRE combines the fuel efficiency of a jet engine with the power and speed of a rocket. The engines can reach Mach 5.4 in air-breathing mode (in other words, while still in Earth’s atmosphere) and Mach 25 in rocket mode for space flight. This is still all theory, as SABRE has yet to undergo full systems test. The space plane for the engines, Skylon, is also still more concept than reality at this point.

Click for company websiteAnother U.K. startup called Bristol Spaceplanes is also developing space planes that can take off and land under their own power. Its first concept is called Ascender. However, Ascender relies on separate jet and rocket engines for ferrying tourists to the edge of outer space. Ascender takes off from an ordinary airfield using its turbo-fan engine and climbs at subsonic speed to a height of about 13 miles. The pilot then starts the rocket engine and pulls up into a steep climb. Ascender has a maximum speed of around Mach 3 on a steep climb and can reach a height of 62 miles above the Earth.

Click for company websiteLastly, a Japanese startup called PD Aerospace is hoping to undercut Virgin Galactic. The 11-person company is developing a fully reusable space plane for tourism capable of reaching an altitude of 62 miles. And like Reaction Engines, it is developing an engine capable of both jet and rocket engine capabilities. PD Aerospace hopes to offer tickets to the edge of outer space for about $150,000 by 2023.


While space planes are far from being a new concept, there are still plenty of technical hurdles to overcome before we see regular service between New York and New Mars. It’s still like the early, early days of electric vehicles, when you had novel prototypes but little infrastructure and just a handful of early adopters. But with the proliferation of spaceports and other infrastructure around the world, we can see a time in the next decade when space planes will become an integrated part of the NewSpace economy. Just watch out for the baggage fees.


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  1. From 1991 to 1997 I went to Boeing facilities with drawings of my hypersonic space plane which used my injection reactor and a compression field engine for flying in the atmosphere which became a repulsion-drive engine in space so that the plane could take off from a conventional airport and fly to the moon or Mars. In 2016 I gave drawings of my space plane and the system that would be used to travel to Mars via the second generation Ground/Ship Launch/Propulsion System which might be able to send people to Mars in three days or less. If my technology works, it would revolutionize space travel and could lead to hyperlight speed space planes and eventually starships.

  2. So your telling me that you have developed an engine faster than light-speed. That is cool, but how did you find enough energy to go faster than light. I though getting to light-speed would require infinite energy. I am genuinely curious.