A few days ago we shared a video of “Abandoned Soviet Era Spacecraft found in Desert”. We were flooded with questions and requests for more information. So the NowScience Team decided to find out the background of the video and report back. But that got me thinking — was it a better Space Shuttle than the American one?
Turns out the video was taken by a photographer named Ralph Mirebs who recently took a trip to the launch facility at Baikonur and took a lot of amazing pictures of the very sad state of the ex-Soviet Shuttle fleet. The original orbiter, Buran, is there, but a roof collapse in 2002 has pretty much ruined it. There’s an atmospheric test orbiter, and the almost-completed second orbiter, Ptichka, left to decay.
They’re striking, melancholy photos to look at, stark reminders of dreams unrealized and wasted potential. But all this attention on the old Buran does give us a good opportunity to really look at what the Soviets made there, and wonder, uselessly and in hindsight, if maybe, just maybe, their space shuttle system might have been superior to the US version
.
The Soviet space shuttle program came about as a direct response to the U.S. Space Shuttle program, because the Soviets saw the U.S. shuttles as primarily military spacecraft, ones that would eventually be configured to carry nuclear bombs. As a result, the Soviet program was highly military in nature, with all manner of strange and ominous mission plans and Buran variants (even some really odd wingless versions) being developed to create in-space nuclear weapon launchers and military space stations.
Most people assume the Soviet space shuttles were just a cheap knockoff of the American shuttles because the orbiters look really, really similar. The truth is way more complex, but a simple answer is that’s sort of half right. The Buran’s basic look and shape was, pretty much, taken from the US shuttles, because even though the Soviets experimented with a lot of quite different-looking concepts, they never found one was that qualitatively better, aerodynamically, from what the U.S. was doing, and since the U.S. had gone through the considerable trouble of proving the design worked by actually launching and conducting missions, there really wasn’t any compelling reason not to just duplicate the basic orbiter design.
Stolen Plans
In the ‘70s and ‘80s, Russian KGB spies systematically stole NASA shuttle designs and smuggled them back to their motherland, as detailed in a 1997 NBC News investigation by journalist Robert Windrem. Later, as America tested its new cosmic vessel, Soviet aircraft and satellites flew reconnaissance missions to aide their own carbon copy.
The American Shuttle Program was never designed or intended to support weaponry. But early on, some Soviet military leaders saw it as a space bomber, capable of materializing over Moscow with nuclear weapons. Those defense leaders used that fear to secure enormous funding for their own shuttle. Even as the East and West negotiated a treaty to prevent weaponizing space, the Russian military ordered a space shuttle of its own.
But instead of building off a Soviet space plane they’d tested more than a decade earlier, Red military leaders thought it best to do what the Americans were doing — construct a hulking and pricey, all-purpose space truck. And because NASA’s shuttle tech wasn’t classified, the Soviets helped themselves to it — saving billions and allowing them to improve on that design.
As a whole the 2 shuttles had the same dimensions, mainly because Buran was made to be a counterpart of the STS Shuttle. But Buran is a little bit lighter than the STS orbiter (62 tons instead of 68 tons). The major difference was at the rear of the shuttles, STS had 3 powerful engines SSME for the lift-off whereas Buran had none. This was due to an important difference in the design process. Buran was only a payload of the Energia LV so its engines was only for the orbit trajectories. The STS Shuttle had powerful engines because they were used for the putting into orbit, but once there they were useless.
This difference lead to another one, Buran needed a launch vehicle whereas the STS Shuttle is its own launcher. So the engines were on the Energia launcher. The scheme of Energia is nearly the same of STS. A central block (2nd stage) with strap on boosters on its side (1st stage). The 1st stage, made of 4 boosters which burned fuel and oxygen instead of solid propellant. This was a major difference in design because liquid propellants are more powerful than solid (chemical), and the engines can be easily controlled (increase or decrease the power, or cutting off), so in case of emergency they could be cut-off and prevent the launcher from 'failure'.
The dimensions of the launcher are nearly the same (the Energia's boosters were smaller), but because Energia used liquid propellant it is more powerful than STS. The boosters of Energia were also reusable but they used a totally different scheme. Once they burned all their propellant they are ejected from Energia in pair (to avoid damaging the shuttle), then they are separated. A small parachute was deployed to slow them down, once the atmosphere became more dense a bigger one was deployed. Finally to slow down near touch down retro-rockets were turned on and landing gears are deployed to land them safe. For STS the boosters were ejected after a 2 min burn. Then a parachute was deployed to slow them down until they reached the Ocean where they hard 'landed'.
Another big difference was that Buran was made to be fully automated or remote controlled, in flight and even in working in orbit (for manipulating payloads). This functionality lead to big differences in the development of the shuttle and the launcher.
The Cockpit - Nose
The cabin of the 2 shuttles had some important differences. First, the cockpit of Buran was fixed on shock-absorbers inside the fuselage, to decrease the vibrations during the flight, and the front thrusters block was more voluminous. The front landing gear of the STS orbiter was in the nose under the thrusters block, whereas the Buran's one was a the junction between the cabin and the payload bay, much more on the back, so the STS orbiter is more tilted during the landing.
On-Board Computer
The on-board computers were made on the same principle, an important redundancy, to avoid errors in processing and hardware breakdown. The Buran's computer was 4MHz (3 MHz for STS), it is composed of 4 independent units (5 for STS), the dead memory is stored on magnetic tapes, the memory of the Buran's computer is 819 200 words of 32 bits (106 496 words of 16 bits for STS) which give it a better calculation power. The engineers of the STS computer decided to use well known languages such as FORTRAN for coding the algorithm whereas for Buran new computer science languages were developed (high and down level). It was more powerful because it used all the power of the hardware but needed more time to make the language and needed more time for the engineers and technicians to be fully ready to work on it.
The Dashboard
The dashboard of Buran was not complete when it flow on November 15, 1988, so it's not easy to compare it with STS. Due to the automatic functionality it was simpler to the STS one.
The Buran's avionics are clear expression of the Soviets' general preference for functionality, rather than sophistication, in design. Compared to the advanced digital-fly-by-wire controls system of the U.S. Shuttle, the Buran's avionics appear rudimentary. On the Soviet side, the Buran cockpit featured mostly dial instruments, rather than digital displays. The Buran test-bed vehicles apparently used an analog version of the flight control system because the digital system was problematic.
The wing
The wings of the two orbiters are strictly the same. They have the same shape, a delta wing with an angle in the leading edge. Elevons at the rear and a protection system to prevent the plasma to come in the structure of the wing.
The Payload Bay - Central part of the fuselage
The payload bays of the two orbiters have the same dimensions and the same function. There is few minors differences in the central part of the fuselage because it's a part where tanks and antennas are stored, so their locations and nature are different. In the early design of Buran the payload bay doors were in metal (titanium alloy), which is very heavy, but the use of composites materials made it possible to decrease the mass of the doors of 600 kg compared to the metal model.
The Remote Manipulator System
The Remote Manipulator System was very different in design and functionality between the two orbiters, but they had nearly the same dimensions the same liberty degrees, tilts angles and strength (payload of approximately 30 tons). The Buran's RMS was 360 kg and the STS's one was 411 kg. Moreover, Buran had two RMS, one on each side of the payload bay, a main RMS and a second in case of failure. The major difference was once again in the automatic functionalities. The Buran's RMS could execute an automatic sequence stored in the computer or could be remotely piloted from Earth by a technician.
Note that the Buran's RMS was not finished for its first flight in 1988. It was planned to be added few years later. Thus the mock-up image.
The vertical stabilizer - rear part of the fuselage
The vertical stabilizer was the same for the two orbiters and had the same function, orientating the shuttle during the re-entry phase and aero-brake function.
The parachute was introduced later on the Orbiter (after the accident of Challenger), whereas Buran has one from the start.
The engines
The rear part of the two shuttles were very different. The STS orbiter had three different kind of engines at the rear, the SSME (for putting it into orbit), the OMS for orbit insertion and RCS (steering system) for precision movement once in the working orbit. Buran had only two king of engines, the mains (which use liquid oxygen and kerosene) and the steering system with gaseus oxygen. This major difference makes the rear of Buran much lighter and less complicated to maintain. Moreover there were no pods (for the OMS) so the engineers decided to put turbojet at the base of the vertical stabilizer to increase the travel distance during the re-entry phase in case Buran miss the entry window. But they were removed for the first flight because the system was not ready yet.
Energy
The energy systems on the orbiters are similar. There was a fuel cell for electricity and Auxiliary Power Units (APU) for the mechanical systems. The electrical energy was given by a fuel cell, it used oxygen and hydrogen to generate electricity and produce water for the crew. The americans also used power cells for their Apollo program whereas Russians used electrical batteries in that time. But they developed a new fuel cell especially for Buran (from the one they made for their Lunar program). This fuel cell was not installed on the first flight of Buran. The power was given by additional batteries (in the payload bay). The energy used for aerodynamic mechanisms (vertical stabilizer, elevons, landing gears) was produced by an APU. For both shuttles there were three networks and three APUs working in case of a failure (103 kW of power for the Orbiter, 105 kW for Buran). They both used hydrazine as propellant.
Heat Shield
The heat shield was a major part of the space shuttle, it protected it during the re-entry in the dense layers of the atmosphere, because the temperature could grow up to 1200°C. The heat shield of Buran was made from three kinds of materials, Reinforced Carbon Carbon plates for the nose and the leading edges of the wings, tiles (38600), black ones mainly of the lower part (where heat is high, they could resist until 1650°C) and white tiles on the other parts of the surface of the fuselage. The thermal protection was mainly ensured by the tiles and also by a coat layer between the tiles and the fuselage.
The heat shield of the STS orbiter was composed of 2 types of tiles (black and white) and RCC material for the leading edges of the wings and the nose. The black tiles of the orbiter could resist to 1260°C. The heat shield was the Achilles' heel of the shuttle. For the STS orbiter the engineers were forced to make another glue to settle the tiles because some of them fell down during the first flight. Moreover, the organisation of the tiles on the surface of the fuselage was very important in comparison of he plasma flow. The engineers working on Buran knew it so developed a very resistive glue (only 7 tiles fell off during the first flight) and they assembled the tiles in a particular way. The tile positioning on Buran was different from the American shuttle. On Buran there were no triangular and acute-angled tiles, and all the long slits between the tiles are perpendicular to the plasma flow. This organisation of the tiles makes it possible to reduce aerodynamic turbulence during the flight. As for the nasal part, the elevons and the drift, the tiles were positioned according to a range. For the change of direction of the joints lines pentagonal tiles were introduced, because they do not have acute angles.
Later the american engineers developed a new thermal protection named Advanced Flexible Reusable Surface Insulation (AFRSI), it was a thermal coat much more resistive to hits than the tiles. They used it where the heat is not too important (instead of white tiles), it seems that the soviet engineers developed something similar but didn't use it.
Security
The security was an important part of the process during the development of the two orbiters. The major parts of the avionics systems came from aviation (where it was well tested and approved), main circuits, tubes, wiring are doubled, tripled or even quadrupled (for the on-board computer), so that a hardware failure is practically impossible.
The main advantage of Buran over STS is that is was made from start to be fully automated. So the computer can take decision more quickly than the crew in case of emergency to save the crew and the payload, by reducing thrust or even eject the shuttle (500 scenaries are stored in the computer). If the shuttle is ejected it will return safely in automatic flight to the landing strip. Moreover, the engines of Energia LV use liquid propellant and can be shutdown if wanted.
The pilot and the co-pilot can also be saved by the automatic ejection of their seats during the ascent (from 50 m to 35 km).
So was it better?
When the U.S. launched our first shuttle, Columbia, in 1981, it had the minimum crew possible — two astronauts. This is, of course, a prudent move when testing a brand-new spacecraft. When the Soviets launched Buran in 1988, it went even further — no crew at all.
The Buran was certainly going to be a crew-carrying vehicle, and it even launched with a special diagnostic module that also offered a bit of extra crew space, much like the SpaceLab modules that flew on NASA’s shuttles. But the Buran was capable of fully autonomous flight, something the U.S. shuttles never even attempted.
The Buran launched, did two orbits, and landed like an airplane all under automatic control — that’s a pretty significant achievement. Such capability is actually quite useful for a space shuttle orbiter, as it would allow for an unmanned rescue shuttle to be launched in situations where a crew may have been stranded due to issues with their shuttle, such as the tile-damage issue that caused the destruction of the Colombia orbiter. NASA spent a lot of time trying to figure out how to cram a full crew into a rescue shuttle flown up by even as few as two astronauts.
The Soviet Energia-Buran system did have some real technical advantages over the NASA Space Shuttle program. But, NASA did manage to do a hell of a lot more with their program, like, you know, actually going to space and doing interesting things. In an ideal world, there would have been cooperation, and perhaps US orbiters could have been retrofitted to work with Energia launchers, and perhaps we’d even have been able to use Energia rockets for Mars missions and and and we’d have permanent lunar bases and Space Unicorns and Infinite Energy satellites that run on rainbows and love and and and...
Sorry, it's a pitty. I guess that’s just not the way the world works.