Author Topic: Formation flying and rendezvous of cooperative targets  (Read 13703 times)

Offline JohnFornaro

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Re: Formation flying and rendezvous of cooperative targets
« Reply #40 on: 11/28/2011 12:50 pm »
Quote from: Savuporo
We keep disagreeing because you insist on discussing repairs.

That's fine too.  I'd like to see it get on with its mission, and there's no doubt that it could use a repair job.  But still, you seem to be considering the idea of a possible repair yourself, which doesn't bother me in the least.  After all, you listed a number of assumptions for such a repair:

Quote
assuming that the current problems with the craft turn out to be software or a non-critical sensor malfunction ... assuming that full control over the craft can be regained, assuming it can be maneuvered ... assuming it could still perform its intended mission ... assuming 10 foot long space aliens don't attack us by then; then, possibly, and only if financially it would make sense and and it actually could be done in time and a number of yet other unlisted assumptions ... there is a remote chance that a propulsive module type of tug ... could be sent up to rendezvous and berth with the craft.

I'm sure that still qualifies as "fantasy" for most here, even though technology to do something like that does exist.

Of course, with all that list of assumptions, and more.  To suggest that such a proposal would be a "fantasy", tho, is to use a loaded term in which we put warp drive, time machines and such.  If however, mere difficulty and unknown high costs would be the new definition of "fantasy", then we could include SLS and JWST in the category as well.

As always, I object to "specialist" definitions which even a politician could not be expected to know beforehand to even have a conversation.

And yet another nit: about those aliens.  I'm going out on a limb here, but I predict they'd not be the problem and easily written out of your list of assumptions.  And by "limb", I mean the "spreading upper portion of a gamosepalous calus or gamopetalous corolla as distinguished from the lower tubular portion", as the term is commonly used.  Which of course, would be the form taken by most aliens that we already "know" of.
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Offline mmeijeri

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Re: Formation flying and rendezvous of cooperative targets
« Reply #41 on: 11/28/2011 12:52 pm »
John, you crack me up! We could all use a bit of levity here, keep up the good work!
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Offline JohnFornaro

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Re: Formation flying and rendezvous of cooperative targets
« Reply #42 on: 11/28/2011 01:53 pm »
Quote from: Martijn
John, you crack me up!

Thanks!  I'll be here all week.  Don't forget to tip your waitress!
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Offline aero

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Re: Formation flying and rendezvous of cooperative targets
« Reply #43 on: 11/29/2011 02:15 pm »
Back to a thought I posted earlier on this thread regarding communications rescue satellites. Hypothesize that a private company (SpaceX, for example) put together a rendezvous capable spacecraft with the right general communications, and perhaps a the capability to allow program upload by the client. The question that comes to mind is this: Would the launch insurance company reduce their rates if such a spacecraft was on standby? Note that looking forward a few years, maybe even Skylon would be available to carry the rescue satellite to LEO.

Do insurance companies even cover situations like FG?
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Offline Jim

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Re: Formation flying and rendezvous of cooperative targets
« Reply #44 on: 11/29/2011 02:36 pm »
Back to a thought I posted earlier on this thread regarding communications rescue satellites. Hypothesize that a private company (SpaceX, for example) put together a rendezvous capable spacecraft with the right general communications, and perhaps a the capability to allow program upload by the client. The question that comes to mind is this: Would the launch insurance company reduce their rates if such a spacecraft was on standby? Note that looking forward a few years, maybe even Skylon would be available to carry the rescue satellite to LEO.

Do insurance companies even cover situations like FG?

No.

A.  There is no need for such a system.   F-G was a bad design.  Other spacecraft would not have FG problems.  There are enough existing ground resources if a spacecraft is properly designed.   FG did not properly plan for contingencies.

b. Gov't payloads are self insured.

« Last Edit: 11/29/2011 02:36 pm by Jim »

Offline kevin-rf

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Re: Formation flying and rendezvous of cooperative targets
« Reply #45 on: 11/29/2011 03:12 pm »

F-G was a bad design. 

Without being able to know what went wrong, that is impossible to tell. What is obvious is bad choices where made, like not having telemetry during the first burn. The vehicle was not ready for flight, it might have or have not been a bad design.
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Offline hop

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Re: Formation flying and rendezvous of cooperative targets
« Reply #46 on: 11/29/2011 05:51 pm »
b. Gov't payloads are self insured.
US Gov't payloads are self insured. The launch of PG was reportedly insured: http://www.russianspaceweb.com/phobos_grunt_scenario.html
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The launch of the Phobos-Grunt mission was ensured for five billion rubles by Russkiy Strakhovoi Tsentr (Russian Insurance Center), including 1.2 billion for the spacecraft itself, covering all contingencies until the vehicle escapes the Earth orbit following its liftoff.

Offline mmeijeri

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Re: Formation flying and rendezvous of cooperative targets
« Reply #47 on: 11/29/2011 06:12 pm »
Self-insured or self-assured?  ;)
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Offline sdsds

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Re: Formation flying and rendezvous of cooperative targets
« Reply #48 on: 11/29/2011 06:45 pm »
F-G was a bad design.

Without being able to know what went wrong, that is impossible to tell. What is obvious is bad choices where made, like not having telemetry during the first burn. The vehicle was not ready for flight, it might have or have not been a bad design.

I see it as likely having been a systems integration problem.  With the success of the MSL launch it's difficult not to compare the two approaches.  Atlas/Centaur is obviously a "good design" for sending a payload onto an Earth-escape trajectory:  a proven launch vehicle with a high energy upper stage.  The Zenit used for F-G didn't/couldn't do that, so the one-of-a-kind spacecraft was tasked with performing its own Earth-departure burn.

There's nothing intrinsically bad about a design that uses the "Fregat SB" (or whatever it's called) solely as a propulsion module, controlled by the host spacecraft.  But when taking that approach the propulsion module imposes some requirements on the host spacecraft, and it looks like F-G didn't meet those requirements.  Specifically in an LEO contingency like the one they experienced it is obviously F-G that must be able to communicate with the ground.  Yet it wasn't designed with appropriate communications equipment to do that.  (No S-band radio; antennas blocked by the Fregat-SB, etc.)

When situations like that happen, where component A imposes requirements on component B that component B obviously does not meet, it's a systems integration problem.  Either the requirement wasn't clearly stated, or it was ignored.

I hope rather than attempting a repair mission they fly some other Earth-escape payload on a Fregat-SB (maybe a repeat Phobos sample return mission, maybe something else).  Of course the next time I would expect them to include an S-band radio and maybe even rent some time at someplace like the Hartebeesthoek ground station.  NB:  NASA was apparently not too proud to do that for the MSL Centaur burn over Africa....
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