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Russian Launch and Mission Thread

tater

By tater
in Science & Spaceflight

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kerbiloid

kerbiloid

Posted
Posted (edited)

"Available to its thrusters", i.e. other three tanks pairs are still full?

***

Nauka heard that she will be the base module of a new station, so after detecting new peripheral equipment attached to her port decided to take the situation under her control.

She just didn't expect such heavy addon.

***

Spoiler

E7eN6ZVVgAYHClq?format=jpg&name=large

So, DKS weren't engaged?

(From the next twit)

Edited by kerbiloid
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Codraroll

Codraroll

Posted
Posted
On 7/28/2021 at 6:51 AM, kerbiloid said:

As far as we know, currently just the cruise propulsion and the docking systems had any malfunction.

And that's kinda the problem, isn't it? There are people whose job it is to know the exact condition of the module, and they didn't catch the major problems with propulsion and docking. What else did they not catch? 

Seeing how this thing behaved after it actually docked, I can't help but wonder when it will start frying the station's electronics, interfering with communications, or just venting air. Obviously the quality assurance team did a terribly poor job and it may still house many lethal dangers.

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RyanRising

RyanRising

Posted
Posted
2 hours ago, Codraroll said:

Obviously the quality assurance team did a terribly poor job and it may still house many lethal dangers.

I think you mean “it may still house many interesting and invigorating problem-solving challenges.” 

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kerbiloid

kerbiloid

Posted
Posted
6 hours ago, Codraroll said:

And that's kinda the problem, isn't it?

Not a problem anymore. It has been propelled and docked, and never needs them again.

6 hours ago, Codraroll said:

What else did they not catch? 

Unlikely there is something same intriguing than the propulsion and docking systems.

The docking system had minor malfunction but was repaired and happily docked it automatically, as planned.
It's a pity, Lyappa is not used to make the show more impressive.

The propulsion system was partially replaced on the assembled module (at least, the whole tanks were done from scratch), so probably they had some issue with it.

The American modules are by order of magnitude simpler, as they are just a pressurized volume with inner structure, with no propulsion or energy.
And they fully depend on a Shuttle.
This one arrived on its own, and it was including complexity of both habitat and tug. This resulteed into additional probability of technical issues, but it didn't need a shuttle.

***

A pure guess.

Looks like once they have started warming the opposite DKS turbopump, the fuel repumping system malfunctioned (i.e. the place where the low- and high-pressure system meet with engines of all kinds), the low-pressure tanks became high-pressure and inoperational (according to that twit).
They immediately stopped pumping and never engaged the other DKS (on photo), so it stays covered.
They realized that they have only 1/4 of fuel available (in the high-pressure tank pair for the RCS engines).

Then they got to the ISS by DPS, and on docking the pressure-fed (via that damaged repumping thing) DPS kept being fed from the high-pressure tank pair, until the fuel finished.
As they have almost totally spent that tank pair on maneuvering, the remaining amount fuel was negligible and ended fast.

So, probably now they have
three full low-pressure tank pairs, but no possibility to turbopump it into the high-pressure for RCS,
empty high-pressure tanks and no fuel for RCS,
all engines unavailable.

The only disadvantage in this case is that they can't use the module RCS for station orientation, so will keep doing it by the RCS of Zvezda, fueling it more often, but never fueling Nauka instead.

8 minutes ago, SOXBLOX said:

#NaukaComedy

#MasterClassOfOldSchool

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K^2

K^2

Posted
Posted
4 hours ago, RyanRising said:

I think you mean “it may still house many interesting and invigorating problem-solving challenges.” 

Rogozin, you forgot to switch accounts. :sticktongue:

9 hours ago, tater said:
Spoiler

 

 

I'm not sure if it makes me feel better or worse overall. On one hand, problem exhausted itself. Great. On another, at no point did any of the systems decide that something's going horribly wrong and tried to shut down themselves. No safeties engaged, no cutoff triggered. It just went "%$#@ it, I'm all in!" If it had any more fuel to burn, it would happily rip ISS apart and keep going. That's terrifying.

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DDE

DDE

Posted
Posted (edited)
41 minutes ago, K^2 said:

I'm not sure if it makes me feel better or worse overall.

Let's put it this way: at the very least, it shouldn't be a mechanical problem like a leak. I don't think it's possible for a bipropellant thruster to malfunction in a manner that would result in a firing.

7 hours ago, Codraroll said:

And that's kinda the problem, isn't it? There are people whose job it is to know the exact condition of the module, and they didn't catch the major problems with propulsion and docking. What else did they not catch? 

I think they just gave up on the propellant system after a decade of mucking about with it.

Anyway, on to the next adventure

 

Edited by DDE
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K^2

K^2

Posted
Posted
17 minutes ago, DDE said:

Let's put it this way: at the very least, it shouldn't be a mechanical problem like a leak. I don't think it's possible for a bipropellant thruster to malfunction in a manner that would result in a firing.

I believe it's still a UDMH+N2O4 fuel. So theoretically, it is hypergolic and can self-ignite if the valves were opened, but you'd have to have both fuel and oxidizer valves happen to fail simultaneously and in a way that still feeds the propellant through the turbopumps. So I don't think this can be anything other than an error in the control systems. Something had to actually command both valves to open for the engine to kick on.

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kerbiloid

kerbiloid

Posted
Posted (edited)

There is one more critically important system onboard, and they yet haven't tested it. It should be done as soon as possible.

Spoiler

Yes, the new toilet.

 

I believe, the hypergolic components were happily stored in same fuel tanks for decades and it never was a problem, and as no engine has exploded, there is no contact between the components, they will just vent out the helium from the rear end of the in-tank bellows to drop the pressure to zero and will never try to pump it.

So, the crew gained additional half-meter thick rad-protection around the quarters for free.

  

48 minutes ago, DDE said:

Let's put it this way: at the very least, it shouldn't be a mechanical problem like a leak.

Exactly. A new pipe attached to the old oven.

Edited by kerbiloid
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DDE

DDE

Posted
Posted
26 minutes ago, kerbiloid said:

I believe, the hypergolic components were happily stored in same fuel tanks for decades and it never was a problem

Those tanks are supposed to be reused over the module's lifetime. Merely storing the fuel without cycling the delicate membranes shouldn't be a problem.

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