This storywas updated at 10:16 am EDT on April 23.
NASA iswatching closely as Russian engineers hunt for the source of a malfunction thatsent a returning Soyuz spacecraft off-course during a Saturday landing.
BillGerstenmaier, NASA?s space operations chief, said Tuesday that it is too earlyto speculate the root cause of glitch or even how much additional peril, ifany, the spacecraft?s three-astronaut crew was in, despite recent Russiannews reports.
?They?reconcerned about the event, but the relative danger to the crew, we?ve had nodiscussion on that at all,? Gerstenmaier told reporters in a teleconference,adding that he had not heard of any claims from Russian officials that thecrew?s lives were in danger. ?They?ve not conveyed to us or conveyed to me anyconcerns at this point.?
TheRussian-built Soyuz TMA-11 spacecraft successfully returnedto Earth on Saturday from the International Space Station (ISS) with Expedition16 commander Peggy Whitson, flight engineer Yuri Malenchenko and South Koreanastronaut So-yeon Yi aboard.
It returnedon a ballistic trajectory, a backup landing profile that sends the reentrycapsule back to Earth in an unguided spin, as well as on a steeper-than-normalcourse that subjects the crew to up to eight times the force of gravity beforeparachutes deploy. Nominal landings hit peak loads of at about six times theforce of gravity.
?It waspretty, pretty dramatic,? said Whitson, who completed a six-month spaceflightwith Malenchenko, in a post-landing audio recording released late Tuesday. ?Gravityis not really my friend right now and 8 Gs was especially not my friend.?
Butsometime during the descent, something went wrong. Instead of hitting itstarget landing zone on the central Asian steppes of Kazakhstan, the spacecraftlanded short some 260 miles (420 km) to the east.
"Therewas no action of the crew that led to this,'' Malenchenko in a post-landingpress conference on Monday, the Associated Press reported. "Timewill tell what went wrong.''
Malenchenko,who commanded the Soyuz during launch and landing, contacted Mission Controlwithin an hour after landing - the earliest he could free himself from thecapsule - using a satellite phone to relay that he and his crewmates were homeand in good health.
Whitsonsaid local Kazakhs were first at the scene, possibly due to a fire nearby thespacecraft. NASA officials said the fire was due to brush burning by nearby farmersand unrelated to the Soyuz landing.
Malenchenkoand Whitson reported being shaken about in their seats early in the landingoperations, which suggests that the three-segment Soyuz spacecraft?s disposablepropulsion module may not have jettisoned as cleanly as designed, Gerstenmaiersaid.
Anotherpotential culprit is an avionics cable that may have shorted out anddirected the Soyuz computers to initiate a ballistic descent, he added.
But Russianand NASA engineers will have a better handle on the anomaly once the Soyuz crewcapsule and its flight recorder are retrieved.
?It may bea month of so before we start hearing anything definitive back from thecommission,? Gerstenmaier said.
Thethree-segment Soyuz spacecraft design has long been Russia?s workhorse ofmanned spaceflight.
They consistof a central 6,393-pound (2,900-kg) crew capsule sandwiched between an orbitalmodule on top and a propulsion module - which includes solar arrays andpropellant - on the bottom. The three modules separate during reentry, leavingthe bell-shaped crew capsule to return to Earth under parachutes andretrorockets.
Gerstenmaiersaid officials know the following:
- Malenchenko and Whitson reported unusual buffeting, jarring and shaking before entering the ballistic descent, suggesting the propulsion module may not have detached properly.
- The Soyuz spacecraft lost radio contact with Mission Control during reentry for an as-yet unexplained reason. While some Russian media reports suggest an antenna may have burnt away, there may have been ground and air-based issues, Gerstenmaier added.
- Malenchenko did report some signs of smoke inside the Soyuz spacecraft during reentry and powered down a display panel at times. Whether the smell came from inside the vehicle or through vents from the exterior is undetermined.
- A short-circuit in a faulty cable prompted the ballistic reentry of the space station?s Expedition 15 crew and a Malaysian astronaut last October during a descent that also included a propulsion module separation malfunction. The two glitches were thought to be unrelated and the module later sheared away due to aerodynamic forces.
Saturday?sballistic reentry of a Russian Soyuz marked the second in a row and the thirdsince faulty gyroscope equipment forced the space station?s Expedition 6 crewto make asimilar landing in May 2003.
?I don?t seethis as a major, major problem, but it is clearly something that should nothave occurred,? Gerstenmaier said. ?I think there is inherent reliability inthis system.?
They serveda pivotal role to continue ferrying astronauts to and from the ISS between 2003and 2005 while NASA recovered from the tragic Columbia shuttle disaster. TheU.S. space agency is also banking on Soyuz vehicles to send NASA astronauts tothe ISS during the gap between the 2010 retirement of its space shuttles andthe first flights of their Orion capsule successor.
More Soyuzspacecraft will also be needed beginning next year, when the space station?spopulation is expected to jump from three astronauts to a full six-personcomplement.
?We?ve beendiscussing with the Russians their ability to support Soyuz production for nextyear,? Gerstenmaier said. ?But again we need to watch and understand what thefailure mode was.?
After lastyear?s ballistic return of the Expedition 15 crew, Russia?s Federal SpaceAgency replaced the faulty cable on new Soyuz vehicles and double checked powerconnections for the explosive bolts governing module separation.
But theSoyuz TMA-11 spacecraft that launched Whitson and Malenchenko into space wasalready docked at the space station by then. The astronauts safeguarded theballistic system cable using additional insulation, but could not check themodule separation system from inside.
The onlyway to check that system in orbit would be in a spacewalk that would requireastronauts to don spacesuits, carefully peel back layers of their Soyuzvehicle?s protective thermal blankets and examine connectors for each of theexplosive bolts, Gerstenmaier said.
?Wedetermined, along with the Russians, that that was probably more risky to goout and pull those blankets back,? he added. ?We didn?t see any more fixes thatdidn?t carry more risk associated with them than leaving it as it was.?
Gerstenmaiersaid he expects NASA and Russian space officials to discuss any new findingsfrom the ongoing investigation prior the planned May flight of the Soyuz TMA-12spacecraft currently docked at the space station. During that flight, NASAastronaut Garrett Reisman and two Russian cosmonauts will move their Soyuz to anew docking port.
?We reallyneed to get the capsule back to understand what occurred,? Gerstenmaier said.?I don?t want us to speculate.?
TheAssociated Press contributed to this report.
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