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Originally Posted by ocpaul20
Link to Livescience.com article
NASA have owned up to an error in reporting the severity of this incident where the Russian research module strangely fired its thrusters making the ISS spin out of control.
The Russian module would not accept instructions locally but needed the comms to come from the Russian space agency. This caused the ISS to spin allgedly for only 1.5 rotations yet the thrusters on the Russian module were firing for 15 minutes and spacecraft would not pass over the Russian comms centre for over an hour.
I am assuming that this could have been a disastrous event if the small thrusters had pushed the ISS towards the Earth or another space vehicle. Maybe this is a problem with having unmanned spacecraft delivering stuff to the ISS because there is no person available to help in an emergency.
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That's not how orbital spaceflight works. You need several kilometers per second of delta-V in order to deorbit the ISS or match orbits with another spacecraft. That would take weeks even if every bit of propellant were expended in a planned burn with all available thrusters, whatever delivery/reboost vehicle was docked, and all the lifeboats. There's not enough fuel on board to do anything fast--except destroy the station, which they came close to doing.
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NASA has stated not only that there was never any danger to the scientists on board (although they declared a "spacecraft emergency")
I wonder if this seriousness was leaked to the press and NASA was 'outed' to the New York Times and had to come clean. I cannot imagine they would explain this event naturally by themselves without some 'prompting'.
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NASA is pretty upfront about anything that happens with the ISS, but they--as a rule--downplay the severity of any incident. A "spacecraft emergency" is just a designation to allocate all ground resources (antennae). In this case, an AVCS failure on the ISS would be a "manned spacecraft emergency" (1a), the highest priority designation of the maximum severity. Every available ground station would be cleared (stop supporting other missions like contacting probes or unmanned satellites) to support recovery efforts. You are correct that there is no higher priority emergency declaration.
There are worse things that can happen, but losing pointing on the ISS is a major incident, like something you'll read about in the next edition of the SMAD textbook and on Wikipedia. The astronauts were in extreme danger for two major reasons
1. The uncontrolled rotation of the station which results in:
a. Solar panels can't maintain pointing (depending on the axis of rotation) and power must be provided by batteries. This condition could destroy the station if not corrected.
b. Thermal control systems may not be able to maintain temperature control. This condition could destroy the station if not corrected.
c. High-gain antennas lose pointing and communications with ground control can degrade or be lost. This can hinder recovery and/or evacuation efforts.
2. The uncontrolled thruster firings which could result in:
a. Damage to the station structure and depressurization of the manned modules, which could kill everyone on board and would certainly require evacuation.
b. Damage to the exterior of the station from thruster plume impingement. Depending on the design and location of the crap Russian module, they may need to spacewalk to make sure the extended thruster firings didn't burn a hole in anything important.
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The original report was that the ISS only moved 45 degrees but in actual fact it spun at least 1.5 times before it was stopped and reversed. These scientists are not astronauts who are trained in 3 dimensional geometry which is needed to stop a spacecraft spinning in space. So, how did they do it and get it under control. I wonder if we have still not been told the true account.
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Having a satellite go into an uncontrolled tumble before recovering it is not all that rare. Having it happen to a manned spacecraft is a big deal. Having it happen to a huge structure like the ISS is very scary. The station is decidedly larger than, say, the Gemini capsule, or any of the Soviet spacecraft that probably spun out of control and killed their pilots.
Ground controllers probably reoriented the station following a pre-planned checklist. All spacecraft have recovery plans for events like this. There is undoubtedly a contingency plan for the astronauts to "right the ship" even in the event of total communication blackout with ground control. Depending on the way the station was tumbling, the rotation was probably tracked and stopped using inertial gyroscopes and thrusters. The orientation was likely restored using sun trackers, earth trackers, and possibly star trackers. I don't know the details of the ISS's AVCS system, but I expect is is very complex and has many, many redundancies.
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Isn't this worrying that the whole space station can be tumbling out of orbit and no-one feels it, and the instruments did not report it, and there was a two-line print-out of the event on the console.
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That's the astronaut toeing the NASA line (and only telling what he experienced in the beginning of the event). You can bet that a LOT of alarms were ringing in mission control. I don't know if mission controllers have a PA system they can use to alert the astronauts to problems, but any communication like that would be carefully vetted before they started giving alerts or instructions. One of the few things that movies get right about spaceflight is that you don't react before you analyze, which is why Mission Control is always telling astronauts to wait. If you react without knowing exactly what's happening, you're just as likely as not to make things worse.
It would be more worrying if the Astronauts did feel it. Anything that puts enough acceleration on the ISS to be sensed by the humans on board would likely destroy the station. It is basically a giant collection of tinkertoys constantly falling around the Earth. As Aerospace Engineers are fond of saying (not within earshot of passengers) an air[space]craft is just a collection of parts flying together in very close formation.
What we need to do to correct the situation is to stop working with the Russians. Their space program has gone straight into the toilet since the 90's. They have two things that still work: The Progress and Soyuz. No other piece of Russian-made equipment should ever get within 400 kilometers of the ISS. Yes, an American, Japanese, or European-made module would cost 4X as much, but it wouldn't be a leaky bunch of duct tape and chicken wire slapped together by bears on unicycles.
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