Author Topic: NASA Announces New Rover to Close Out Decade of New Missions  (Read 95929 times)

Offline Jim

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #120 on: 12/06/2012 10:08 pm »
I thought the cruise stage had it's own RCS,

It does, but is just for cruise and a spinning spacecraft.

Offline FOXP2

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #121 on: 12/06/2012 11:18 pm »
[quote author=Jim link=topic=30528.msg988527#msg988527
How not to be a dick is not to ask to be spoon fed data.  I am not going to waste time helping someone who is lazy and makes unsubstantiated comments.
[/quote]

Lazy, funny, is this place "work" to you? No no maybe your right and I guessed wrong and this forum is in fact your job, for which a work ethic is to be applied, and can be critical to those of us whose job is not this forum, and don't have the time to dedicate to it as you do.

I did, I can't find answers to
-What is the max max range of Electra?
-What is Electa bit rate at that max range?
-Could ASRG be used on this upcoming rover?

ASRG will NOT be used on this rover. Mentioned earlier in the thread. I could explain a million reasons why, but the simplest one is that NASA will not put ASRG on a $1.5 billion mission until it is flight tested first on a cheaper mission. Another reason is that you don't want to "clone" Curiosity and then put an entirely different power system on it. That would add risk to the design.

So what if their is not enough plutonium? Yes, yes your fingers cross they begin production in 2 years of 2.5 kg a year, but has there yet to be actually funding allocated for that? 

Yes the ASRG weighs less then half as much as a MMRTG and gives off ~20 watts more electric power, but those don't exactly sound like detriments. I guess a entirely new heat exchanger would be needed to try to suck enough heat out of an ASRG. But just answer me this, if there was "hypothetically" not enough plutonium for an MMRTG, would you side with an ASRG then?   

Quote

Relay is not an issue. I don't know why you guys seem to be obsessed with it, but once MAVEN's primary mission is over it's going to be used for relay until it falls out of the sky. And ESA's going to have an orbiter too. There will be plenty of comm. I work with Mars scientists and they're not worried about the relay issue. Not an issue. There are better windmills to tilt at.


Good, could you ask them "if there were no orbiters would it be an issue then? By the way it was Mars scientists that proposed the cancelled MTO so clearly some of them thought it an issue. Thankfully with Electra any orbiter mission can do the job, but NASA won't be launching another after MAVEN for the rest of this decade, and that will likely be the only NASA orbiter in operation by 2020, assuming no catastrophes.


Now if you really think flying a lander and orbiter together is a "bad idea" take that up with the designers of Viking, Mars Express, ExoMars, etc.     


Mars express is not a relevant example since Beagle was a secondary.

No US lander since Viking, Pathfinder, MPL, MER, Phoenix, MSL haven't flown with orbiters and that goes with future ones too.

So if we call the lander a "secondary" its alright to pack them together?

Pathfinder, MPL, MER and all weighed a 1/3 as much as Viking (~1 ton total mass per mission verse 3.5 tons for viking) and were launched on much smaller cheaper Delta II verse Viking on Titan IVs. In fact only MSL reached and exceeds viking by 300 kg and was launched on the the Titan IV successor, the gloriously expensive Atlas V. MSL weighs 0.9 tons plus 2.5 tons for the EDL system, Viking lander only weighed 0.6 tons plus 0.5 tons for heat shield. A 3.5 ton MSL-EDL plus even a 1 ton MAVEN type orbiter as well as the fuel for orbital insertion would likely require a rocket bigger then the Atlas V and much much more money.     

Offline RocketEconomist327

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #122 on: 12/07/2012 12:02 am »
Quote from: Jim link=topic=30528.msg988527#msg988527

How not to be a dick is not to ask to be spoon fed data.  I am not going to waste time helping someone who is lazy and makes unsubstantiated comments.
<snipped a bunch of crap>

Some people here need to recognize who the hell they are talking to before they start popping off at the mouth and lobbing grenades.  Grenade lobbing is good when you know who you are targeting and know what your doing... you know neither.

We are on the ball for restarting Pu238 production.  We need to finish ITAR first. 

Thank you for the explanation on relay - we will be fine.  Can we let that dead horse lay there... dead... pretty please?

VR
RE327

edited for clarity
« Last Edit: 12/07/2012 12:21 am by RocketScientist327 »
You can talk about all the great things you can do, or want to do, in space; but unless the rocket scientists get a sound understanding of economics (and quickly), the US space program will never achieve the greatness it should.

Putting my money where my mouth is.

Offline Blackstar

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #123 on: 12/07/2012 12:05 am »
FOXP2, when people mix the posts that they are replying to, cutting and pasting all over the place, I don't really read them. They just make posts far more complex than they need to be.

Offline FOXP2

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #124 on: 12/07/2012 03:15 am »
Quote from: Jim link=topic=30528.msg988527#msg988527

How not to be a dick is not to ask to be spoon fed data.  I am not going to waste time helping someone who is lazy and makes unsubstantiated comments.
<snipped a bunch of crap>

Some people here need to recognize who the hell they are talking to before they start popping off at the mouth and lobbing grenades.  Grenade lobbing is good when you know who you are targeting and know what your doing... you know neither.

So I should appeal to authority? I shouldn't ask questions or ask for evidence and just take you on your word?

Quote
We are on the ball for restarting Pu238 production.  We need to finish ITAR first.


Oh so you have the money then?

Quote
Thank you for the explanation on relay - we will be fine.  Can we let that dead horse lay there... dead... pretty please?

We will probably be fine you mean, or does being the authority grant you clairvoyance too? 

Offline Jim

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #125 on: 12/07/2012 03:48 am »

1.  Pathfinder, MPL, MER and all weighed a 1/3 as much as Viking (~1 ton total mass per mission verse 3.5 tons for viking) and were launched on much smaller cheaper Delta II verse Viking on Titan IVs.

2.  In fact only MSL reached and exceeds viking by 300 kg and was launched on the the Titan IV successor, the gloriously expensive Atlas V. MSL weighs 0.9 tons plus 2.5 tons for the EDL system, Viking lander only weighed 0.6 tons plus 0.5 tons for heat shield..     

Correcting a bunch of crap

1.  Wrong comparison.  Look at landed weight.  MER (rover and lander) was almost the same as Viking, 0.59 tons.

2.    Wrong. You are comparing apples and oranges.   To do a proper comparison, since Viking has its instruments and lander combined, MSL weight includes the rover and descent stage (the lander).  So, triple the  the MSL weight  and that is your comparison.  Or just compare only the Viking instrument weight to the MSL rover.  Who in their right mind would think MSL was a just marginal increase over Viking? 

Also, Titan IV was much more expensive than Atlas V.

So know what you are talking about.  The landers after Viking were much more efficient in landed weight.   

Offline Jim

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #126 on: 12/07/2012 03:52 am »

Oh so you have the money then?


Money isn't the issue.  It is politics. 

Offline RocketEconomist327

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #127 on: 12/07/2012 05:29 am »

Oh so you have the money then?


Money isn't the issue.  It is politics. 

Bingo
You can talk about all the great things you can do, or want to do, in space; but unless the rocket scientists get a sound understanding of economics (and quickly), the US space program will never achieve the greatness it should.

Putting my money where my mouth is.

Offline cleonard

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #128 on: 12/07/2012 07:37 am »
Is someone going to talk about repurposing the ejected off-set weights, too?  ::)

Actually, it is by far the easiest mass to repurpose.  You see there were other methods studied to offset the flight angle for control.  The weights were the lowest risk.  I like the trim tab option the best.  High loads for sure, but I will guess the tab might have weighed 30kg.  That would have freed up 120kg for more useful payload.  That is a massive number.

What would you have done with that mass?
« Last Edit: 12/07/2012 07:39 am by cleonard »

Offline Robotbeat

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #129 on: 12/07/2012 07:39 am »
Is someone going to talk about repurposing the ejected off-set weights, too?  ::)

Actually, it is by far the easiest mass to repurpose.  You see there were other methods to offset the flight angle for control.  The weights were the lowest risk.  I like the trim tab option the best.  High loads for sure, but I will guess the tab might have weighed 30kg.  That would have freed up 120kg for more useful payload.  That is a massive number.

What would you have done with that mass?

That's not exactly what I meant. I meant people were trying to repurpose everything discarded on the way down, from the descent stage to the cruise stage. It is silly.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline kevin-rf

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #130 on: 12/07/2012 10:00 am »

...Viking lander only weighed 0.6 tons plus 0.5 tons for heat shield..     

How much did the Viking cruise stage, eer orbiter weigh again? That is why it flew on a Titan! If you had separated the two, it could have flown on smaller rockets, maybe.
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Offline Star One

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #131 on: 12/07/2012 05:14 pm »

...Viking lander only weighed 0.6 tons plus 0.5 tons for heat shield..     

How much did the Viking cruise stage, eer orbiter weigh again? That is why it flew on a Titan! If you had separated the two, it could have flown on smaller rockets, maybe.

Out of interest would the Falcon 9 be capable of launching this rover along with its EDL and cruise stage?

Offline kevin-rf

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #132 on: 12/07/2012 05:18 pm »

...Viking lander only weighed 0.6 tons plus 0.5 tons for heat shield..     

How much did the Viking cruise stage, eer orbiter weigh again? That is why it flew on a Titan! If you had separated the two, it could have flown on smaller rockets, maybe.

Out of interest would the Falcon 9 be capable of launching this rover along with its EDL and cruise stage?

Considering MSL launched on an Atlas 541, don't you mean Falcon Heavy?

Edit: If you ment the Viking lander, you have to remember the entire stack weighed 3527 kg, of which 1445 kg was fuel to break into orbit. At Viking's point in history, we did not know enough about mars to safely do a direct entry, so they broke into orbit and then looked for and selected a landing site. Since then we have had several (Path Finder, MER, Phoenix) successful direct entry landers launched on Delta II's, the same rough class as a Falcon 9.
« Last Edit: 12/07/2012 05:30 pm by kevin-rf »
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Offline Star One

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #133 on: 12/07/2012 05:28 pm »

...Viking lander only weighed 0.6 tons plus 0.5 tons for heat shield..     

How much did the Viking cruise stage, eer orbiter weigh again? That is why it flew on a Titan! If you had separated the two, it could have flown on smaller rockets, maybe.

Out of interest would the Falcon 9 be capable of launching this rover along with its EDL and cruise stage?

Considering MSL launched on an Atlas 541, don't you mean Falcon Heavy?

That's a good point and by then the FH should have clocked up enough flights to prove its reliability for such a mission.

Offline kevin-rf

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #134 on: 12/07/2012 05:33 pm »
That's a good point and by then the FH should have clocked up enough flights to prove its reliability for such a mission.
For the just announced next rover, Falcon (9 or Heavy) needs to be Nuclear certified.
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Offline Star One

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #135 on: 12/07/2012 05:35 pm »
That's a good point and by then the FH should have clocked up enough flights to prove its reliability for such a mission.
For the just announced next rover, Falcon (9 or Heavy) needs to be Nuclear certified.

I would guess that's an involved process?

Offline kevin-rf

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #136 on: 12/07/2012 05:43 pm »
Jim and Blackstar would be the ones to answer that. Since the Atlas V is the only nuclear currently certified launcher, it is more likely that the next rover will be going on an Atlas V.

I am curious since the 2018 and 2020 windows are more favorable than MSL's, will they be dropping a solid or two off of the Atlas? (531? 521?).
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Offline Star One

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #137 on: 12/07/2012 05:46 pm »
Jim and Blackstar would be the ones to answer that. Since the Atlas V is the only nuclear currently certified launcher, it is more likely that the next rover will be going on an Atlas V.

I am curious since the 2018 and 2020 windows are more favorable than MSL's, will they be dropping a solid or two off of the Atlas? (531? 521?).

But would keeping them and launching it in the 541 configuration allow the rover to reach a greater area of Mars?

Offline kevin-rf

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #138 on: 12/07/2012 05:53 pm »
But would keeping them and launching it in the 541 configuration allow the rover to reach a greater area of Mars?

No, if you can reach Mars, you can reach all of Mars. Launching on a 541 in a more favorable windows gives you either more mass to Mars (if the Sky Crane can land the extra mass) or more margin in the event of LV under performance.
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Offline Star One

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Re: NASA Announces New Rover to Close Out Decade of New Missions
« Reply #139 on: 12/07/2012 06:05 pm »
But would keeping them and launching it in the 541 configuration allow the rover to reach a greater area of Mars?

No, if you can reach Mars, you can reach all of Mars. Launching on a 541 in a more favorable windows gives you either more mass to Mars (if the Sky Crane can land the extra mass) or more margin in the event of LV under performance.

Thanks for that. Those reasons you have given for using the 541 actually sound like they could be pretty good reasons for using it in these launch windows.

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