Phobos Hopes Grow, as Soyuz Docks to ISS

A European Space Agency ( ESA) tracking antenna in Perth Australia is making repeated successful telemetry contacts with the Russian Phobos spacecraft stranded in low earth orbit on what was to be twin upper stage engine firings to propel it toward Mars after launch Nov. 9. Photo Credit: Roscosmos

A European Space Agency ( ESA)  tracking antenna in Perth Australia is making repeated successful telemetry contacts with the Russian Phobos spacecraft stranded in low earth orbit on what was to be twin upper stage engine firings to propel it toward Mars after launch Nov. 9.

The antenna had been modified to transmit extremely weak signals because the most likely Phobos communications system to acquire was tuned to deep space operations. The ploy worked.

If the contacts continue and can be expanded to Russian antennas there is the potential that the mission can still be sent to Mars, although the window for a successful return of samples may have been exceeded. If that occurs there is still 31 lb. of imaging and sophisticated soil analysis instrumentation that can function on the surface of the moon.

There is substantial analysis under way by the Russians on whether an alternate mission can be performed, such as a landing and sample return from the Moon, or from an asteroid.

The ground measures to save the Phobos mission are shaping up is one of the great saves’ in the history of space flight.

Shortly after launch the Russians found  they  could not track, and therefore locate the spacecraft, nor acquire  any telemetry from it.

Critical tracking data from U. S. military space tracking facilities, apparently operated by U. S. Air Force Space Command, were eventually  routed to Russian space officials , according to Lev Zeleny, one of Russia’s top scientists.

U. S. cooperation of that nature would not be unusual, but would require special permission from the White House and State Dept. for it to occur.

On Nov. 10, Zeleny, the director of the Moscow based Space Research Institute (IKI) reported to a U. S. colleague “that the U.S. military had provided significant help in establishing exact orbital parameters” of the then lost Phobos-Grunt spacecraft. Grunt in Russian means “dirt”, signifying the sample return nature of the flight.

This data was to be used to send commands to the spacecraft as it was passing within range of Russian ground control stations. Zeleny said that the mission team still had had a “few days for reprogramming before the end of the Mars accessibility window for 2011,” according to U. S. based Russian space journalist, Anatoly Zak.

Zeleny at IKI in Moscow sent this report to Zak, who heads the authoritative Russian Space site. In fact the Russian Space Web is the most up to date open source of information about what happened to the Phobos bound spacecraft after its successful launch into an elliptical orbit only about 128 x 215 mi. inclined 51.4 deg. to the equator.

The 51.4 deg. inclination was perfect for departing Earth toward Mars, but few tracking antennas on Earth are positioned to monitor low altitude elliptical spacecraft at that inclination. This was making it hard to contact the spacecraft for any length of time to send commands and receive data back.

The Zenit booster’s flight was perfect. The next step was for a powerful Fregat upper stage mounted on the spacecraft and modified for deep space cruise,  to ignite twice to send the 13 ton Phobos lander and piggyback Chinese  Mars orbiter into deep space.   But the Fregat, modified with a extra donut shaped drop tank to carry extra fuel for the maneuver  failed to ignite.  The spacecraft appears to be maintaining attitude control, however, meaning small attitude control engines are firing under attitude computer command.

What follows is a detailed summary of Phobos mission status from Zak as carried on the Russian Space as the emergency situation developed after launch.

Zak’s notes show how desperate  the situation was becoming.

According to Zak’s  Nov. 10  report, “Multiple sources including the official board of the flight said at 01:46 Moscow Time that several attempts throughout the night to communicate with the spacecraft had not been successful, including the use of specialized uplink hardware at Baikonur.  As a result, the cause for the failure of the mission to leave Earth orbit remained a mystery. New attempts to send commands to Phobos-Grunt were scheduled for 18:00 Moscow Time.”

Russian graphic shows launch trajectory (red) and initial orbit (yellow). At bottom left are spacecraft images showing 2 Fregat firings and resulting two higher orbits, but these two firings never occurred stranding the spacecraft in lower orbit (yellow). Normal trajectories and milestones, including separation of donut shaped drop tank that never too place are also shown. Image Credit: Roscosmos

“However after the second orbit, the spacecraft was found transmitting no signals and no telemetry. At a ground station in Baikonur, ground controllers attempted to re-boot Phobos-Grunt’s flight control computers, and were planning to repeat the same attempt during the upcoming night,” the Russian Space Web said.

“Zak says  that one theory was that the spacecraft’s flight control computer reset itself to a pre-launch state, awaiting a signal to re-initiate its flight program.”

“During the day, ground stations of the European Space Agency, located in Australia and in Kourou, French Guiana also attempted to communicate with Phobos-Grunt, apparently without any success.

Zak noted, “As one informed source on the Novosti Kosmonavtiki forum reported,  the main problem with controlling the spacecraft had stemmed from the fact that the probe’s low-gain antennas might’ve been obstructed by the [new donut shaped] external tank of the Fregat main propulsion system, thus preventing signals from the ground reaching the flight control computers. In the meantime, the probe’s high-gain antenna was in folded position at that phase of the flight. To make the situation worse, for some unknown reason, the spacecraft would not downlink telemetry to the ground.”

“In the meantime, Russian ground controllers were preparing for yet another round of attempts to communicate with the spacecraft during evening hours of November 10 and early hours of November 11,” reported Zak.

According to the Russian Space Web into Nov. 11, “All efforts to contact Phobos-Grunt proved futile and attention of the press was quickly switching to the inevitable uncontrolled reentry of the spacecraft into the Earth atmosphere,” said Zak.

Zak said,  data from Nov. 11  indicated that all operations onboard the spacecraft during its transfer from the initial parking orbit to the transfer orbit had been designed to be conducted exclusively under automated control and no two-way communications with the ground would be possible. As a result, current attempts to control the spacecraft in its parking orbit were completely improvised. Still, one participant in the project maintained, without much detail,  that establishing control over the spacecraft was still possible.

He also noted that, “ Several independent observers reported seeing Phobos-Grunt moving across the sky without discernable flashing —  possible evidence that the probe’s attitude control system was keeping it from tumbling in space.

Phobos spacecraft minus insulation shows circular Fregat propulsion system that failed to fire. Large tanks are the Fregat’s standard complement but the donut shaped drop tank at very bottom of spacecraft was added specifically to fuel the initial two burns never achieved. Photo Credit: Roscosmos

“All attempts to establish contact with the Phobos-Grunt spacecraft made by Russian and European ground controllers during the night from November 11 to November 22 proved fruitless once again,” said Zak.

There were  major positive developments for the Russian and U. S. space programs late Nov. 14 when the Soyuz TMA-22 spacecraft was launched with the crew to start the Expedition 30 mission to the International Space Station.

On board were Soyuz Commander cosmonaut Anton Shkaplerov and  flight engineers   cosmonaut Anatoli Ivanishin and U. S. astronaut Daniel Burbank who will stay in space till March 2012.  They docked with the ISS Nov. 16 to replace Expedition 29 astronauts and ISS Commander   Mike Fossum and Russian  Flight Engineer  Sergei Volkov  and Japanese astronaut Satoshi Furukawa, who will returned to Earth  Nov. 21.

The Phobos spacecraft situation remained unchanged into Nov. 21 except the attitude was still being held properly by the Phobos spacecraft thrusters.

As hope faded and the spacecraft’s orbit began to decay toward a reentry in late December of Early January, Zak recalled what he had written before launch.

“Even after the funding for Phobos-Grunt had improved in the second half of the decade, the project was plagued by mismanagement, unnecessary political pressure and serious technical problems,” said Zak. “ When this complex spacecraft with all its numerous unflown systems finally reached a launch pad, many insiders still considered its chances for achieving its main goal – returning soil from Phobos – close to nil.”

The Soyuz TMA 22 spacecraft launched Nov. 14 to the ISS marks the final TMA version of the Soyuz. The coming block change to the Soyuz design will have better avionics and environmental systems and an overall improvement in reliability. Photo Credit: Roscosmos
Missions » ISS »

Museum Spotlight: Hill Aerospace Museum

MSL Takes First Steps on Road to Mars