For many many people space tourism and even colonisation are attractive ideas. But in order for these to start we need vehicles that will take us to orbit and bring us back.
Current space vehicles clearly cannot. Only the Space Shuttle survives past one use, and that's only if you ignore the various parts that fall off (intentionally!) on the way up.
You could be forgiven for thinking that space is therefore an impossibly expensive place to get to. But this need not be the case. Launch to orbit requires accelerating to Mach 26, and so it uses a lot of propellant - about 10 tons per passenger. But there's no technical reason why reusable launch vehicles couldn't come to be operated routinely, just like aircraft. The only reason why this hasn't been done yet is that launch vehicle development has been left to government space agencies. And they have had neither the priority nor the will to achieve it - they don't use even 2% of their budgets (of $25 billion per year) to study the design of launch vehicles suitable for passenger service!
So it may well turn out to be private enterprise that is the solution - plenty of ideas for reusable launch vehicles exist, and with incentives like the X-Prize, there's going to be fierce competition to see who can be first. The "Space Age" will also be the "Rocket Age" since rockets will be the main means of traveling in space. There are various different kinds of rocket engine, but the traditional chemical rocket engine (in which a fuel and an oxidizer are mixed and the hot gases produced are ejected in the opposite direction to the direction of travel) will be the "work-horse" of life in space, like motor-car engines on Earth. To date most rocket engines are made to operate only once on an "expendable" vehicle, like a missile. So rocket operations are extremely expensive and small scale, and rocket engineering is still a small, specialized field.
In the Rocket Age, rocket engines and rocket vehicles will be "reusable" like all other forms of transportation. Railways, shipping lines, airlines etc don't use the word "reusable" because it's obvious. We don't talk about "reusable cars", "reusable buses", or "reusable aeroplanes". So it should and will be with space vehicles. So, far from being a small technical back-water, rocket engineering is still in its early days and has yet to see its heyday.
So we're looking forward to the era in which chemical rocket engines of many sizes and shapes are in everyday use - the "work-horses" of life in orbit. Without trying to predict the details such as what size and types of vehicles, what orbits, what types of engine and so on will be used, it is possible to foresee many of the broad outlines of the "rocket age". For example, rocket vehicles for launch, for in-orbit operations, and for longer trips such as to the Moon and back, will differ in many ways - though some may be multi-purpose, probably particularly at the early stages before the different markets are large enough to support more specialized vehicles. Specifically, vehicles used for launching from Earth to orbit and returning to Earth need to have aerodynamic and thermal protection which isn't needed for operations in space. Vehicles that operate only in space will have weird and wonderful shapes without concern for aerodynamics, but to have minimum mass among other constraints.
Another example is that although using LH2 (liquid hydrogen) / LOX (liquid oxygen) engines is in some respects more tricky than, say kerosene / LOX engines, it has the advantage that LH2 and LOX can be made by splitting water (H2O) using electricity. In orbit electricity can be generated from sunlight - so without using any fuel - and so wherever there's water you can make rocket fuel. This will be very useful in orbital operations, and we can envisage propellant stores comprising large insulated tanks for both LH2 and LOX, with insulated piping and pumps for recompressing gas to liquid, large water tanks, large solar panels for generating electricity, docks for receiving bulk supplies, exhangeable tanks, specialised delivery vehicles, pumps for supplying customer vehicles - whether passenger craft returning to Earth, small local orbit "taxis", cargo craft heading up to the Moon or further out, and others. The detailed design of these facilities to make them economical and competitive, raises loads of fascinating design issues. But with an orbital tourism business generating tens of $billions of turnover, it's easy to see that such business opportunities will exist. And from a business point of view they're far more promising, near-term and potentially profitable than plans for a possible government-financed base on Mars possibly 40 years from now.
Overall, as rockets will be for life in orbit as motor-cars are on Earth, the rocket business is going to grow to have all the infrastructure that the car industry has on Earth: sales operations, hire firms, lease firms, orbital propellant bases, specialised repair shops, licensing, standard maintenance procedures, spare parts suppliers, second-hand stores, innumerable accessories, and scrap dealers. There'll even a whole range of leisure-related activities: races, rallies, collectors, antique dealers and restorers. There'll also be a corresponding range of new careers - pilots and stewardesses, mechanics, parts suppliers, and numerous business roles such as freight-forwarders, traffic-controllers, lease-financiers and insurance.
Taking the middle path
Some people support the development of more advanced launch technologies, such as rocket-sled launchers, scramjet engines, magnetic launchers running up a mountain-side, "orbital towers" and so on. But no-one has ever yet tried the simple chemical rocket approach. Why did the upstart DC-X caused such waves? Simply because no-one ever did it before. It could have been done (and was proposed) more than 30 years ago in the USA. And when it was finally done a few years ago it was not by NASA but by the Department of Defense, because they want cheap access to space.
The DC-X during one of its test flights
So let's try the simplest, oldest, but still untried approach of chemical rockets before we give up and look to complex new technologies that may or may not work, but in any eventuality will certainly take a long time to develop and cost a lot more money.
Then again, some people are against the whole idea at all - some of their most common objections are:
- "Developing one or other of these vehicles would be prohibitively expensive - it would cost $10 billion".
Cost estimates are controversial, but they're continually coming down. "Venture Star" is estimated at $6 billion. But even $10 billion would be less than half what government space agencies spend every single year!
Even if it did cost that much (which is doubtful), if the public were given the choice they would certainly vote to give money for this rather than for much of what the space agencies currently use this money for. Spread over 5 years it would be less than 10% of their budgets - after which all the agencies' activities would cost a fraction of their present cost. Clearly a bargain.
- "It will be impossible to license rocket powered vehicles for passenger transport".
This is an easy one - they already have been! In the 1950s the RATO (rocket assisted take-off) version of the De Havilland Comet jet airliner was certified to carry passengers. Thus there's a legal precedent, and even space agency managers would probably agree that what has been done before can be done again!
A lot of technology has advanced enormously since the 1950s when many of today's rockets were designed - and many problems are now essentially solved - for example navigation. Remember how in the 1960s astronauts used to do training in case they landed in a desert or a snow field and no-one knew where they were? This is now impossible. You just need a $1000 box common in Tokyo taxis and you know where you are within a few meters anywhere in the world - and of course everyone else knows as well.
Everyone's seen pictures of rockets taking off - both real ones and imaginary ones. And everyone's seen pictures of spaceplanes taking off - but they're all imaginary - because they're impossible! (or at least, be prepared for a long wait). The basic problem for designers of reusable space vehicles is achieving the velocity needed to reach orbit without carrying so much fuel that the vehicle is either too heavy to get there or unable to carry anything other than fuel. So the answer is either to make the vehicle very light, or to find a way around having to carry all that fuel.
There's more than one way to do it
1 - HTOL 2STO
The problem with planes is that wings contain very little fuel, but they have a big surface area, so they're heavy. Their advantage is that they can generate lift in the atmosphere so that a launch vehicle uses much less propellant in the first part of its trajectory. But that isn't enough of an advantage to overcome their weight problem - so HTOL (Horizontal Take-Off and Landing) SSTO (Single Stage To Orbit) is impossible with existing or near-term materials and propulsion technology.
However, HTOL is possible with a little help: various kinds of assisted-launch HTOLs are possible - like a rocket-powered launch-sled or dropping off from a balloon at high altitude. Unfortunately these are not at all convenient for commercial operations!
Alternatively, TSTO (Two Stage To Orbit) or 2STO, and also so-called 1.5STO designs are possible, and may well become attractive systems. Good examples of these are the Spacecab/Spacebus 2STO design which has a first stage like a large Concorde that takes off using existing jets and then uses existing rockets to climb to high altitude (about 40 km) where it releases the upper stage already almost outside the atmosphere. The upper stage or orbiter is like a smaller, blunt (good for re-entry) first stage, using existing rockets to get to orbit, and then small jet engines for landing.
1.5STO is the approach by the Black Horse and Pioneer Rocketplane team. A vehicle looking rather like the Spacebus upper stage takes off from a runway with almost empty propellant tanks. Then it refuels in mid-air, using technology that's been used for decades by Air Forces. It thereby gets to "launch" fully fuelled at high altitude, neatly getting round the impossibility of HTOL SSTO.
Another ingenious 1.5STO is the approach taken by Kelly Space Technology. Their winged spaceplane will take off horizontally, fully fuelled but unpowered, towed behind another aircraft. In this way they too can get to high altitude before they have to use any of their propellants. Neat - we wish them luck!
2 - VTOL SSTO
The advantage of VTOL compated to HTOL is that it's structurally simple - or can be if you design it right. Circularly symmetric (forget all the complexities of wings!), VTOLs are a "flying propellant tank", a bullet shape that is inherently stable on reentry -- like the early space "capsules". VTOL is known to be possible with 30-year old technology. The Kankoh-Maru is one currently active VTOL that typifies this kind of vehicle; the DC-X and Roton, both now defunct, are others.
3 - The Duckbilled Platypus option
Strictly speaking there's also VTOHL (Vertical Take-Off, Horizontal Landing), of which the most obvious example is the Space Shuttle. However, it's not a good design as it has a number of fundamental problems.
The key difficulty of SSTO design is to build a light vehicle, and so the structure must be as efficient as possible. In a VTOL vehicle the loads are basically along the vehicle from bottom to top. In a HTOL vehicle they're mainly across the vehicle like an aeroplane. But a VTOHL has to support stresses both along and across the vehicle - so it's heavier. Secondly, once a VTOHL vehicle has taken off, there's a period of time during which it can't easily recover from a failure. This is contrary to the fundamental idea of aviation safety, namely the need for "continuous intact abort". At any given moment time it must be possible to save the vehicle and passengers in the event of an accident or systems failure. The Challenger disaster was a vivid demonstration of this problem of VTOHLs, and they're unlikely ever to be satisfactory for transporting people or to be able to pass certification for passenger-carrying. But convince us if you can!
Another problem with VTOHL is that while the wings help the vehicle on re-entry, they are effectively dead weight on the way up. In an HTOL, wings allow you to use aerodynamic lift at take-off, so you don't need to use so much thrust and propellant -- the thrust of a VTOL rocket's engines is typically 1.4 times its mass, while the thrust of an airliners' engines is only about 1/4 of it's mass - big saving!. So to build wings and just carry them vertically to orbit is shooting yourself in the foot! Finally, so much fuel is needed just to get up that it's very hard to keep any in reserve for the return trip, resulting in an unpowered high-speed landing. Airliners can rev their engines at any time and "go round again" if there's a problem before landing - but the space shuttle would be destroyed. Even Chuck Yeager didn't like doing "dead-stick" landings in a fighter plane, because of this risk.
4 - The Rest of the Field
In addition to the above, there have also been proposals for two stage vertical launch vehicles, and even a single-stage-to-orbit space station that launches itself!
In the Blue Corner...
Now, there are dedicated, professional, convincing (even noisy!) supporters of both HTOL and VTOL approaches, and both are certainly possible - in the right configurations. Rather than take sides, Space Future would like to see both getting funded and being built and put into operation. The competition between them will be just great to watch, and it'll help to improve the designs, drive their costs down, and speed things along nicely!
The War's Over
Unfortunately the space industry suffers from the problem of having been a government activity for decades during the "cold war". As a result there are numerous research establishments with expensive equipment in many countries which these institutions want to use, because it's embarrassing to them to admit they're a waste. So they're always coming up with ways of spending money on anything except passenger launch vehicles.
Projects working on scramjet (supersonic combustion ramjet) engines are a good example of this. They sound great, taking oxygen from the air instead of carrying it with you -- but they're essentially pointless technology, at least for civilian use. They'll certainly never be used in any commercial vehicle. Think about it - Supersonic Combustion Ramjet means that it can't operate below supersonic speeds. So it needs another engine to take off with. And it's an air-breathing engine, so it can't operate in space either! So you need rockets on board. So you need 3 different propulsion systems -- heavy and complicated!
Worse, experiments have shown that while originally planned to go to Mach 26 or Mach 20, scramjets can't work much above about Mach 11. And to use them a launch vehicle has to cruise in the atmosphere at that speed -- rather like standing in front of a welding torch -- instead of just getting out of the atmosphere as quick as possible. But there are expensive hypersonic wind-tunnels which "have to be used", and so instead of trying to make a launch vehicle that might actually make money (what a thought!), government institutions keep thinking up plans why they should continue this work instead.
Well, if these organizations want to waste taxpayers' money, what's new? "Who cares?" you might ask. What must not be allowed is for these organizations to block the start of the true space age by justifing projects like this with the ludicrous claim that "This is the way to open the space frontier" - it isn't. The way to open the space frontier is to build passenger vehicles with existing technology and to start passenger services. It's as simple as that.
Keep it Simple
Henry Ford didn't wait for the V-8 engine to be developed before he started selling cars! He made them with the engines he could make at the time, and he got started! And then with the money he earned he improved his products step by step. It's going to be the same with space travel. It's going to start with what's available - not with what might be developed decades from now, if enough billions of taxpayers' money is used (and probably not even then, as X-33 has ably demonstrated).
And so that means making and operating VTOL SSTO vehicles, and 2STO/1.5STO HTOL vehicles. So we're looking forward to seeing vigorous competition between different models of these different vehicles, and to seeing which companies and which countries play a significant role in humans' approaching space future - and to seeing which ones keep their heads in the sand, and their people in the dark, until the race is lost!
Vehicle Designs
In order for people to be able to travel economically to space, for space tourism and for other purposes, we need reusable launch vehicles. All commercial transport industries use reusable vehicles - and so will the commercial space transport industry. Luckily research aimed at developing low-cost reusable launch vehicles has increased recently - though total funding is still barely 2% (!) of government funding for space activities.
The following is a list of projects under way today and some significant projects of the past. Some are aimed initially at sub-orbital flights - a much easier target than getting to orbit, as demonstrated by SpaceShipOne. Others are designs for orbital vehicles. Ultimately, the only ones of importance are the piloted, passenger-carrying vehicles.
SPACESHIPONE
WHITE KNIGHT
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Winner of the $10m Ansari X-Prize, this suborbital passenger-carrying spaceplane was designed by
Burt Rutan's Scaled Composites, famous for graphite composites, and also the integrating contractor for the former
Roton. Following their successful bid to win the X-Prize, Scaled Composites
are now turning their eyes to the next step: the development of a commecially
viable passenger-carrying suborbital space vehicle. SpaceShipOne
features a rubber-nitrous oxide hybrid rocket engine and cold gas attitude
control thrusters; a graphite/epoxy primary structure; 3-place, sea-level,
shirt-sleeve cabin environment; a low maintenance thermal protection system;
and a unique feathered reentry system. The spaceplane is carried under the belly of Scaled Composites' White Knight carrier aircraft. The White Knight is a piloted, twin-turbojet research aircraft derived from the Proteus intended for high-altitude missions. Its first flight was on August 1, 2002. It provides a high-altitude airborne launch of SpaceShipOne. The White Knight is also equipped to flight-qualify all the SpaceShipOne
systems, except rocket propulsion. The aircraft's cockpit, avionics, life
support systems, pneumatics, trim servos, data system, and electrical system
components are identical to those installed in SpaceShipOne.
The White Knight drops SpaceShipOne at 50,000 ft. SpaceShipOne
then climbs nearly vertically under power at a 3-4g acceleration. The hybrid
engine burns out at Mach 3.5, 65 seconds after ignition. The spaceplane coasts
to approximately 100 km. (328,000 ft.) before free-falling back to earth.
Pilot and passengers experience microgravity above the atmosphere for 3.5
minutes. Before reentry, the pilot raises SpaceShipOne's
twin tails to vertical. This feathering approach stabilizes the spaceplane
without need of pilot input. Reentry deceleration is up to 5gs. After reentry,
the pilot returns the twin tails to horizontal, and SpaceShipOne glides to a runway landing.
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KANKOH-MARU |
A passenger-carrying reusable
SSTO
VTOL rocket designed to carry 50 passengers to 200 km Earth orbit started as part of a study program by the
Japanese Rocket Society. Since none of the space agencies of the world were studying how to make launch services available to the general public, the
JRS
started a Space Tourism Study Program in 1993, with the objective of getting
the price of a flight to orbit down to around $10,000 per passenger. Work
on
Kankoh-maru has grown steadily in depth and breadth ever since, and has helped to accelerate the acceptance of space tourism as the direction for space development work today.
Based loosely on earlier designs such as the "
Phoenix", the design has been described in a number of publications (many by
Isozaki), and is currently being further refined in the third phase of the
JRS study (See: The JRS Space Tourism Study Program Phase 2).
(In Japanese, "Kankoh" means tourism, and "Maru" means circle, symbol of Japan. Most ships are called "Something-Maru" so
Kankoh-maru
means roughly "SS Tourism". In 1852 the Dutch government gave the Japanese
government its first modern ship, a steam and sail-powered ship. This was
called "
Kankoh-maru", though at that time the implication of the name is said to have been more nearly "Light of the Nation".)
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| ASCENDER |
Ascender is a sub-orbital spaceplane from Bristol Spaceplanes carrying two crew and two passengers intended to provide proof-of-concept for the development of the Spacecab/Spacebus spaceplane, and is capable of reaching space (though not orbit). As well as being an entrant for the X-Prize, Ascender is intended to return commercial revenues through its passenger carrying capability.
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SPACEBUS
SPACECAB |
Spacebus a design for a 2-stage passenger-carrying
HTOL by the company Bristol Spaceplanes
in Britain. The first stage uses jet engines for take-off, followed by rocket
engines to climb to high altitude for separation, after which the upper stage
uses rocket engines to reach orbit. This configuration has a number of advantages
described at length in papers by David Ashford (including the recent "Space Tourism - How Soon Will it Happen?" and the 1990 book "Your Spaceflight Manual: How you could be a tourist in space within 20 years").
Using existing jet and rocket engines is very attractive in reducing initial
development costs. And though new air-breathing rocket engines might be more
efficient, they're not needed initially (the first stage just has to be a
bit bigger and use a bit more fuel). And going high with the first stage makes separation easy as it's in thin air, so even hypersonic loads are small.
Spacecab is a scaled-down version of Spacebus designed to carry 6 passengers. It's attractive as a first step to
HTOL
launch services since it uses only existing technology, and could start passenger
operations much earlier than a vehicle requiring new engines to be developed.
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| MICHELLE-B |
Michelle, or 'Modular Incremental Compact High Energy Low cost Launch Experiment', is a manned reusable sub-orbital
SSTO proposed by TGV Rockets. Its modular structure is designed to allow a variety of payloads such as scientific instrumentation to be substituted.
By
aiming at the sub-orbital market first, Michelle aims to bridge the gap to
more expensive orbital vehicles by allowing the necessary technology to be
developed incrementally. |
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| BLACK ARMADILLO |
Armadillo Aerospace is a research and development team headed and funded by computer games entrepreneur
John Carmack.
The Texas-based team has already developed small manned and unmanned atmospheric
test landers powered by hydrogen peroxide rockets. Armadillo Aerospace is now competing for the X-Prize with what it believes to be the simplest possible design.
The rocket, dubbed Black Armadillo,
is powered by four hydrogen peroxide engines feeding from a 1000 gallon composite
fuel tank. A computer takes attitude measurements from gyroscopes and uses
those measurements to throttle the engines 200 times per second, stabilizing
the craft. The pilot can also steer the rocket via joystick. The pilot and two passengers sit with their backs to the nosecone.
This unusual position is taken to ensure that the occupants encounter reentry
deceleration on their backs as the vehicle reenters the atmosphere nose first.
Ascent acceleration is considered by Armadillo Aerospace to be mild enough to permit the unorthodox seating arrangement.
The
rocket lifts off vertically, and at burnout coasts up to 100 km (62.5 miles).
The rocket makes a nose-first reentry, with foam insulation protecting the
aluminum nose section from reentry heating. A drogue chute frees the main
parachute, and landing is cushioned by an expendable aluminum nose cap that
compresses on touchdown. |
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| KELLY ECLIPSE |
Another approach to the problem of achieving
HTOL from Kelly Space & Technology
- towing the vehicle like a glider at take off in order to save using fuel
in the early part of the flight, thereby starting at high altitude with full
propellant tanks. It should be possible to get this to work - like in-air
re-fuelling and two-stage
HTOL. Which will end up with the lowest operating costs? Time will tell!
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| SPACECLIPPER |
The SpaceClipper SC-1 is a suborbital reusable
VTOL spaceplane proposed by SpaceClipper
International, designed to carry up to ten passengers and two flight crew
to an altitude of 140 km and back. Although it descends horizontally, it
takes off and lands vertically. The SC-1
features shield doors which protect the craft during ascent and descent,
but open to allow views of space and Earth for the four minutes that the
vehicle is weightless at the top of its trajectory. A follow-on fully orbital spaceplane dubbed SC-2 is also proposed,
building on the experience gained in developing and operating the SC-1.
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| XERUS |
Xerus is a two-person reusable spaceplane proposed by XCOR
Aerospace, which takes off and lands like a conventional aircraft. It is
capable of climbing suborbitally to 100km using a cluster of reusable rocket
engines developed by XCOR
to use non-toxic propellants. After a short period of weightless free fall
the vehicle then re-enters the atmosphere. While the primary market for
Xerus is space tourism, the vehicle is also being targeted at microsatellite delivery and suborbital science payloads.
XCOR's primary business is the development of reusable rocket engines, in pursuit of which they previously developed and flew the EZ-Rocket
airplane as a demonstrator and test bed for their reusable rocket technology.
Much of the engineering team previously worked on the propulsion systems
of
Roton at the former
Rotary Rocket company.
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ALPHA |
The
Alpha Project is a fully reusable two stage vehicle proposed by
World Aerospace, Inc. The upper stage, dubbed the
Alpha CX-1A
SRV
(Space Reusable Vehicle) is a three-person spaceplane designed to take one
pilot and two mission specialists into space. Intended to use off-the-shelf
technology where possible, the CX-1A may also be launched from the ground
as a suborbital spacecraft. Interestingly, three potential configurations for the
lower stage (or launch vehicle) are being proposed as development proceeds:
The first is an Air Launched Horizontal Landing (ALHL) solid rocket booster
RLV
derived from the Pegasus by Orbital Sciences Corporation. This vehicle will
carry the CX-1A upper stage for the flight test phase. The second is a
HTOL liquid rocket flyback booster
RLV. This vehicle will carry the CX-1A in the piggyback configuration and is ultimately expected to evolve into the final
RLV lower stage as the design matures.
The third is a
VTOL
rocket booster option. In this configuration the CX-1A will be launched
atop currently available commercial launch vehicles such as the Boeing Delta IV-M
EELV, the LMCO Atlas V 500, and an
RLV based on the Thor (a former USAF ICBM)
World Aerospace, Inc.
is targeting the Alpha series of space planes for orbital and suborbital
space tours, as well as crew transfer, small satellite launches, and emergency
rescue. |
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BLACK HORSE
PATHFINDER |
An innovative
HTOL design by
Mitchell Clapp
using in-flight refuelling of a single-stage vehicle to enable it to reach
orbit. Taking off with almost no liquid oxygen in its tanks, it can then
effectively "take off" with full tanks at high altitude. The upper stage
of a 2-stage vehicle is limited to a mass of about 100 tons, whereas Black Horse
could have a fully-fuelled mass several times this. Air forces use in-flight
refuelling routinely and have accumulated enormous experience, so safety
should not be a problem. Currently being pushed by the company Pioneer Rocketplane.
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| KISTLER K-SERIES |
A concept for a series of
VTOL vehicles leading up to a passenger-carrying version. Currently Kistler Aerospace Corporation is developing a 2-stage
VTOL launch vehicle for small satellites.
In 1997 Kistler Aerospace moved to Australia and will start launching from Woomera.
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| STAR BOOSTER |
Fully reusable
VTOHL first stage launch vehicle for boosting a range of upper stages to orbit. Based on the Ukrainian-built "
Zenit" rocket using kerosene and
LOX engines, and promoted by
Buzz Aldrin and Ron Jones. See "Star Booster - A Commercial Solution to Cost Effective and Versatile Reusable Space Transportation".
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| SPACE ACCESS |
A
TSTO spaceplane design from Space Access LLC. The first stage uses an "ejector ramjet" to power a hybrid airbreathing engine in the first stage to reduce aerodynamic drag.
The
second stage, which can use one of several different configurations, is contained
inside the first and released at high altitude. |
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| CANADIAN ARROW |
The Canadian Arrow is a two-stage suborbital rocket designed to take three people into space and back.
The
first stage is a liquid propellant stage whose aerodynamic shape and thrust
chamber are closely based on the V2 rocket, which was also the basis for
the Mercury rocket used by Alan Shepard. It boosts the vehicle to the edge
of space at a maximum of 4.5G acceleration before detaching and falling back
for a parachute-slowed splashdown and recovery. To assist in recovery, the
first stage has a natural positive buoyancy achieved without the use of floatation
gear. The second stage uses solid rocket engines to rise to an eventual
maximum altitude of approximately 70 miles. It is also designed to be an
escape pod and can be separated from the first stage at any point, including
the launch pad in an emergency. In normal flight, it will reenter the atmosphere
using a reentry ballute and three main parachutes to make its own splashdown
roughly 15 miles down range. |
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COSMOPOLIS XXI |
The
Cosmopolis XXI is a two-stage sub-oribtal spacecraft proposed by the
Cosmopolis XXI
Suborbital Corporation and
Myasishchev Design Bureau (
MDB) designed for sub-orbital space tourism. It is an X-Prize contender.
The
first stage carrier is the M-55X "Geophysika", which will climb to a 17km
altitude before ascending at a steep angle to 20km where the second stage
Cosmopolis XXI (or
C-21) disengages and separates.
The
C-21 second stage is a rocket powered lifting body
RLV
capable of carrying a pilot and two passengers to a peak altitude of roughly
100km (62 miles). Once the rocket engine burns out the crew compartment
separates from it, after which it will enters free-fall for a few minutes
before descending and re-entering the atmosphere. Descent is achieved though
the deployment of aerodynamic control surfaces, followed by a landing divided
into an initial glide-phase and a final parachute-assisted touch down. |
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COSMOPOLIS XXI |
The
Cosmopolis XXI is a two-stage sub-oribtal spacecraft proposed by the
Cosmopolis XXI
Suborbital Corporation and
Myasishchev Design Bureau (
MDB) designed for sub-orbital space tourism. It is an X-Prize contender.
The
first stage carrier is the M-55X "Geophysika", which will climb to a 17km
altitude before ascending at a steep angle to 20km where the second stage
Cosmopolis XXI (or
C-21) disengages and separates.
The
C-21 second stage is a rocket powered lifting body
RLV
capable of carrying a pilot and two passengers to a peak altitude of roughly
100km (62 miles). Once the rocket engine burns out the crew compartment
separates from it, after which it will enters free-fall for a few minutes
before descending and re-entering the atmosphere. Descent is achieved though
the deployment of aerodynamic control surfaces, followed by a landing divided
into an initial glide-phase and a final parachute-assisted touch down. |
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| KITTEN |
Kitten is a suborbital resuable vehicle taking three people, 1 pilot and two passengers, proposed by the Cerulean Freight Forwarding Company.
Designed to attain an altitude of around 235km, the expected flight time
is 45 minutes, of which 6 are in zero G. The craft is powered by novel ceramic
composite engines with a fuel mixture of either Propane/Lox or Methane Lox.
As well as being a potential X Prize contender, an expendable second stage named 'mitten' is also planned, to enable Kitten to launch microsatellites to
LEO. CFFC intend to market Kitten as a kit for assembly as well as sold as a completed vehicle.
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CALICO
ANGORA |
Two larger versions of the vehicle are also proposed for the future: Calico, a short stay
LEO vehicle capable of carrying 9 people or 2 tonnes of payload, and Angora, a much large vehicle capable of sustaining 40 people in
LEO
for up to two weeks, aimed at the space tourism market. Both these larger
vehicles are designed to use a metallic wire mesh parafoil to assist in reentry.
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| SPACE CRUISER SYSTEM ® |
SCS
is a fully recoverable fully reusable piloted passenger carrying sub-orbital
2-stage spaceplane being offered by Vela Technology Development and the basis
of the ticket deposit scheme being offered by Zegrahm Space Voyages,
intended to operate from and return to a commercial airport with a flight
time of the order of 2½-3 hours. The booster stage, Sky Lifter, carries the
second stage Space Cruiser underneath it on a pylon on twin turbojet engines.
After separation, the second stage uses Nitrous Oxide/Propane pressure fed
rocket engines to reach space. Zegrahm ultimately expects to be able to fly two flights a week
whilst the vehicles are being designed to be capable of upto two flights
a day. Space Cruiser ® and Sky Lifter ® are registered trademarks of Vela Technology Development, Inc.
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| COSMOS MARINER |
A technologically advanced 4 passenger
SSTO spaceplane design from the company Lonestar Space Access (formerly Dynamica Research), Cosmos Mariner uses conventional jet engines for take-off and landing, thus allowing it to use the existing FAA air traffic control system and make use of existing airport infrastructure, an issue which
VTOL
rockets have yet to address. The rocket engines are also planned to use jet
fuel which is considerably less volatile than liquid hydrogen. Cosmos Mariner requires advanced and as yet undeveloped technologies though not all of them will be needed for its X-Prize bid.
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| POGO |
As an example of how airbreathing engines could be used, the
Pogo is intended as the first stage of a
TSTO
or MSTO launch system. Shown here using existing jet engines from the F-15
it is expected to reach at least Mach 2.5 and 80,000 ft before releasing
a Pegasus-sized vehicle. Jet engines being developed for a proposed hypersonic
commercial transport ("Hypersonic Transport Propulsion," Aerospace Engineering,
June 1996, pp 7-11.) could take a much larger Pogo
to Mach 5 and 100,000 ft. For many payload sizes, low-cost jet engines can
do the job of rockets in the region where rockets are most expensive and
inefficient. |
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| SKYLON |
SKYLON is the successor to
HOTOL being developed by Reaction Engines
Ltd. It is an unpiloted fully reusable aircraft-like vehicle capable of transporting
12 tonnes of cargo into space and is intended as a replacement for expensive
expendable launchers in the commerical market. |
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| SPACECUB |
An unusual and innovative strategy, SpaceCub
is a sub-orbital four-seater rocket vehicle aimed at the future hobbyist
market as an all-inclusive kit for an expected price of somewhere between
a quarter and half $million, though you'll have to supply the fuel yourself.
A possible X-Prize contender.
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| SPACE VAN |
The Space Van is designed to carry 16 passengers plus a flight crew of 3 to
LEO.
A reusable booster stage accelerates the orbiter to around mach 3 at 30km
altitude; the relatively low velocity compared to other booster designs allows
a simpler and less complex design. Proposed by Space Tour, an unmanned cargo carrying variant is also on the drawing board.
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DELTA CLIPPER (DC-X,
DC-XA, CLIPPER GRAHAM) |
The Delta Clipper was a proposed
VTOL orbital vehicle. The DC-X and later DC-XA (derived from the DC-X) were low-speed, reusable test-vehicles built by
McDonnell Douglas
which flew 12 times between 1993-96, until suffering major fire damage after
falling over when a leg failed to deploy on landing. On a total budget of
about $100 million provided mainly by the US Department of Defense (DoD)
and
McDonnell Douglas
Aerospace, they demonstrated that reusable rocket vehicles can be flown repeatedly
and routinely by a small team - essentially like an aircraft. Having inherited the project from the DoD, NASA cancelled it after spending some $40 million. Instead, NASA spent $1,300 million over 5 years on the
X-33 and
X-34, neither of which ever flew before being cancelled. Go figure!
It's notable that, apart from its computers, the DC-X
could have been built 30 years earlier - and indeed a proposal for such a
vehicle was made at that time by the Douglas company, a fore-runner of McDonnell-Douglas.
Why it wasn't built, and why NASA cancelled the the DC-XA, are key to the stagnation in the space industry.
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| CAC-1 |
A sea-launched sub-orbital
VTOHL rocket using
LNG/
LOX engines, the CAC-1
was intended to carry six passengers from port city to port city as a rapid
transit service, a transatlantic flight taking about 12 minutes. Designed
and promoted by
Advent Launch Services, the project was eventually scrapped after the company failed to raise
sufficient financing through a deposit scheme. The original start of commercial service was to be July 4 1999. A former X-Prize contender.
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SASSTO |
A piloted, reusable
SSTO
VTOVL rocket designed in the 1960s by the late
Philip Bono of the (then) Douglas Aircraft company - the source of much
SSTO
VTOVL
thinking. Based on the 3rd stage of the Saturn rocket, this would have been
a great way to exploit some of the systems developed for the Apollo project.
For political reasons
SASSTO was not developed; the Saturn rocket was thrown away; and we had to wait until 1993 for the (much less capable) DC-X to demonstrate the first steps of the
VTOVL approach.
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BETA |
A design for a reusable
SSTO
VTOL by
Dietrich Koelle at
MBB in the early 1970s (see "Beta, A Single Stage Reusable Ballistic Space Shuttle Concept"). A key study keeping the
VTOL lineage alive!
BETA 2 was a later version.
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|
PHOENIX |
One of the key vehicle designs in the lineage of
VTOL rockets. Designed primarily by
Gary Hudson and produced during the 1980s by
Pacific American Launch Systems in a number of versions, including the "E" (excursion) version to carry passengers for the "
Project Space Voyage" with the travel company
Society Expeditions in 1985. Many of the same team went on to work on
ROTON.
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|
ROTON |
Planned by
Rotary Rocket Inc, the
Roton was to use a centrifugally-pumped rocket motor for launch, and a helicopter rotor for descent. By their own estimate
Rotary Rocket needed over $100 million for development, but managed to raise only $30 million, and so ceased trading in 2000.
The photo on the left is of the
Roton
ATV (Atmospheric Test Vehicle) that was rolled out of its Mojave hangar facility
in March 1999. This vehicle made 3 successful piloted test flights, demonstrating
the feasibility of the rotor-assisted landing. |
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|
HOTOL |
In 1984, British Aerospace proposed the
HOTOL
horizontal takeoff single-stage-to-orbit reusable launcher. The concept featured
a new type of airbreathing rocket engine that would have burned compressed
air rather than liquid oxygen up to a speed of Mach 5.
HOTOL was studied in great detail both by BAe and the ESA Winged Launcher Configuration study.
The concept eventually gave way to Interim
HOTOL
in the early 1990s, a British/Russian joint proposal which replaced the (technologically
risky) airbreathing rocket motor with existing Russian RD-0120 engines. The
vehicle would have been launched piggy-back from a Russian Antonov 225 aircraft.
Alan Bond, the inventor of
HOTOL's airbreathing propulsion system, later refined the concept as SKYLON, above.
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|
SSX |
The Space Ship Xperimental was a modified version of the
Phoenix
VTOL rocket, used by
Max Hunter to help persuade the US government to fund
VTOL research, ultimately leading to the DC-X project. It is described in "Halfway to Anywhere" by
G Harry Stine.
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SAENGER |
This is a design for a 2-stage
HTOL launch vehicle produced initially by the company
MBB in Germany (see "
Sanger: An Advanced Launcher System for Europe").
The first stage would use air-breathing rocket engines (which have not yet
been developed) to reach approximately Mach 6, at which the upper stage would
separate and use rocket engines to reach orbit. Piloted versions of the
upper-stage have been designed to carry 36, 40 and 44 passengers. |
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|
X-33 |
The "
X-33" was announced by NASA in 1995 as an unpiloted, reusable
VTOHL rocket test vehicle. It was expected to fly to speeds reaching Mach 13, with test flights starting in 1999.
The plan was very soon after scaled back to reach only Mach 8, and then cancelled in 2001 after NASA's entire budget of more than $1 billion had been spent, leaving it several $billion short of having a flight vehicle. (Article)
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| VENTURE STAR |
A supposedly commercial follow-on to the
X-33 demonstator. However, the proposer, Lockheed-Martin
Corp, had stated that the satellite and government launch markets for which
it was designed were not large enough to make it a viable business venture,
and so it has expired with the
X-33.
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|
X-34 |
The
X-34 was announced as an unpiloted, reusable
HTOL
rocket test vehicle to fly first in 1999, eventually reaching Mach 8. The
main objective was to provide a flight-test vehicle for the NASA developed 'Fastrac' engine and some other hardware. Having overrun the original $100 million budget by 30%, NASA's
request for an addition $200 million was turned down and the project was
scrapped in 2001 before any flights were performed. (Article)
By contrast, the piloted, reusable
HTOL rocket-test-vehicle, the X-15, reached Mach 6.6, flying successfully 199 times in the 1960s.
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The race is on
So when we talk of rockets at Space Future, we mean only "reusable" engines and vehicles. And we won't report much news about expendable rockets, because they're of little relevance to starting the Space Age. That depends on developing reusable vehicles - through test vehicles like DC-X and X-33 to Kankoh-maru, Pioneer Rocketplane, Roton, Spacecab, "X" Prize contenders, and others. Interestingly, from a business point-of-view, for manufacturers there's still "everything to play for". For example, certain engines will become the mainstream engines favoured by many different rocket vehicle designers, leading to huge orders and continuing spare parts business. Which engines will they be? The winners in the Rocket Age will be made more like car-engines or aircraft engines than expendable rocket engines today - repeatedly reusable, with standard maintenance, overhaul and repair procedures. Almost no rocket-engine manufacturer has made significant steps in this direction yet. But like a lot of business, it's basically a race, and one thing we can be sure of is that those who don't even start won't win!
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