Phobos-Grunt status, launch plus six days
Posted by Emily Lakdawalla
14-11-2011 18:37 CST
I said I wasn't going to post again unless the spacecraft talked to us, but I changed my mind because finally there were official comments today about the status of the mission from Roskosmos head Vladimir Popovkin. There was a press briefing about the successful launch of the Soyuz with three astronauts to the Space Station -- which is a story in itself -- but naturally most of the media's questions had to do with Phobos-Grunt.
Here is the text of the statement, translated by reader Dmitry Kulshitsky, for whose help I'm immensely grateful!
The spacecraft Phobos-Grunt will have time through January, said the Head of Roskosmos Vladimir Popovkin today.
"We have time till January inclusive, the spacecraft will stay in orbit, but the Mars departure window closes in early December," said the Head of Roskosmos Vladimir Popovkin today.
"There is still a chance, but we were not able to receive any telemetry yet to understand what happened. The problem is that tracking stations are slow [that is, they cannot turn fast enough to track a fast-moving spacecraft on a low-Earth orbit] and Phobos-Grunt is on an unplanned trajectory, hence the communication session lasts for only 7 minutes."
"All systems of the spacecraft work nominally, it maintains its orientation toward the Sun, so it's not over yet. At the moment engineers conduct attempts to upload software."
Answering journalists' questions regarding when it would be possible with a high degree of certainty to talk about the "spacecraft death", he said that "it would be possible to talk about this in early December when the window for departure to Mars is closed." "We can start the end of 'Phobos' predictions when the orbit degrades to 180 kilometers," added Vladimir Popovkin.
The Head of Roskosmos has also rejected rumours that the spacecraft has design flaws in its construction. He reassured that "This version does not match reality."
He has also highlighted the fact that the possible fall of 'Phobos' to the ground does not present any danger to Earth. "There is no doubt that the spacecraft will explode upon the re-entry as it approaches denser layers of the atmosphere," said Popovkin.For more on the challenges of tracking Phobos-Grunt from Russian ground stations, read Anatoly Zak's page about that. The spacecraft's fast orbital speed results in two big challenges for the engineers trying to save the mission. First, the deep-space antennas are just not designed to track fast enough to follow a spacecraft in a low-Earth orbit. Also, the fast, low orbit results in very short passes. Even if they could track it, it's hard to acquire the signal, uplink commands, and receive downlink in the very little time available.
There are a couple of notable things about Popovkin's remarks. For one thing, he said the spacecraft can stay in orbit through January at least, and that they have until early December to get the spacecraft off to Mars. Both of those timescales are longer than ones previously stated by unnamed "experts" in media stories. He officially confirmed that the spacecraft is maintaining its sun-pointing, which can be observed by using Earth-based telescopes. More curious is his statement that "all systems work nominally." Yet they have not received any telemetry from the spacecraft. It is hard to understand how they can be certain of "nominal" operation without any telemetry from the spacecraft.
There was a flurry of news stories following his statements today, and some of them provide a little additional detail and context. RIA Novosti now has a nice index page to all of their Phobos-Grunt coverage. This RIA Novosti storyexpands on the radio tracking issues:
Popovkin told reporters why it is difficult to control the device. According to him, the problem is that "there is a range of all domestic stations were previously used for deep space exploration." Now the "Phobos-soil" flies on a contingency trajectory at an altitude of 200 kilometers from the Earth, and the communication with each of the measurement points does not exceed two minutes, said the head of Russian Federal Space Agency.
He also said that authorities are trying to specialists, in particular, to accelerate the turning mechanism unit. In addition, the station was supposed to start working when it would be several tens of thousands of miles from Earth, and transmitter power was set so that the signal reached there, said Popovkin. According to him, experts feared that at close range it will burn too strong signal hardware probe.So, in addition to the challenges I outlined above, their radio stations may be having a hard time broadcasting quietly enough not to harm the spacecraft. (The radio signal can't literally "burn" the spacecraft, but it seems conceivable that a radio receiver designed to listen for very faint radio signals from millions of kilometers away might be harmed by the loudness of the same signals sent from very short range.)
Here's another interesting remark:
Roscosmos head Vladimir Popovkin denied information on their existing spacecraft "Phobos-Grunt" design flaws that may prevent the establishment of contact with it.
Earlier media reports that the device has a design flaw: one of its antennas pointing towards the ground, the other grayed [blocked by?] tank with fuel and propulsion system.
"I'm from you first hear it," - said Popovkin told reporters. He noted that currently the Russian Space Agency experts are trying to establish control over the "Phobos-Grunt."This is referring to discussion taking place on many forums suggesting that the radio antenna that the spacecraft's controllers are trying so hard to talk to is blocked by the jettisonable fuel tank of the modified Fregat upper stage rocket engine.
Speaking of forum discussions, they've started a new thread at nasaspaceflight.com to follow the continuing Phobos-Grunt saga. That and Russianspaceweb remain the best English-language places to find news.
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