April 29, 2009

Russia Considering Rocket Guided Landing System For Spacecrafts

The follow-up spacecraft to Russia's Soyuz capsule may be equipped with rocket thrusters that would aid in landing.

According to the BBC, engineers of RKK Energia, Russia's developer of manned spacecraft, are considering plans to use rocket thrusters for spacecraft landing. Previous missions have returned to Earth by use of a parachute or wings.

The current method of Russian manned space missions involves the Soyuz capsule, which actually uses small propellers to gently aid in landing, but its parachute does most of the work.

In 2007, Russia decided to construct a launch site, named Vostochny, in order to end reliance on the site in Baikonur, which became part of the republic of Kazakhstan after the call of the Soviet Union.

However, the decision to construct the new site also led to a dilemma of having only a small narrow strip of land in the European part of Russia where space capsules could be guided back to Earth.

This dilemma led Russian engineers to come up with new ideas on how to guide future crafts back to Earth with an unprecedented amount of accuracy.

Thus the idea of rocket-assisted landing was born as engineers determined the method could allow for an accurate touchdown on a patch of land of two by five kilometers.

In July RKK Energia unveiled the first sketches of the Advanced Crew Transportation System (ACTS), which Russia had hoped to collaborate with Europe on.

However, the lack of a parachute in the spacecraft's crew capsule drew criticism. Instead, it featured 12 propellant-burning rockets that would be used for guiding the craft safely and gently back to Earth. Additionally, the craft featured retractable legs and a re-usable thermal protection system.

Nikolai Bryukhanov, the leading designer at RKK Energia, presented the proposed craft at the 26th International Symposium on Space Technology and Science in Hamamatsu, Japan. He said the craft would begin firing its thrusters at an altitude of between 600 and 800m, and precision landing would be initiated at an altitude of 30m above ground.

"It was explained to us how it was supposed to work and, I think, from the technical point of view, there is no doubt that this concept would work," Christian Bank, lead designer of manned spacecrafts at EADS-Astrium in Bremen, Germany, told BBC News.

But since the end of 2008, there have been hints of reports of a brewing debate among Russian officials regarding what they call PPTS, or Prospective Piloted Transport System.

According to BBC, in April 2009, the semi-official RIA Novosti news agency quoted an unnamed RKK Energia official as saying that the future spacecraft would use an environmentally-friendly liquid propellant - such as alcohol - during its touchdown.

But regardless of plans to use liquid propellant, critics claim the plan for rocket engines is simply too risky, and an alternative has been raised which would use a combination of rocket thrusters for landing and a parachute for emergencies.

In the 1990s, the US tested an unmanned prototype, called DC-X, which used rocket thrusters for liftoff and landing, but the project was abandoned after the end of the Cold War.


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