Author Topic: NASA builds asteroid capture mission definitions  (Read 21873 times)

Online Robotbeat

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Re: NASA builds asteroid capture mission definitions
« Reply #40 on: 04/03/2014 02:54 AM »
But still, OSIRIS-REx has a total cost of about $1 billion. If I had to guess, I'd say the asteroid return is probably worth a good two OSIRIS-RExes, so maybe about $2 billion. Not enough to justify the whole expense, but perhaps enough to justify the cost of the unmanned capture vehicle itself.

But I asked about the "mission", not just the capture spacecraft. To get mission cost you have to add the cost of the SLS HLV launch vehicle and the cost of the launch. That totals quite a but more than $2b total. That's where I'm going with this. That is a lot of money for a single mission. Can this be done with a different, less expensive vehicle, say a Falcon Heavy or a Delta IV Heavy for example? At least then there is an effort to contain costs instead of finding a mission for a seldom used HLV.
Yeah, well then I agree. Not justifiable unless you're already counting SLS and Orion and all that enormous expense as a "sunk cost." May be possible as a public-private partnership or with using a Falcon Heavy + Dragon.
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

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Offline KelvinZero

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Re: NASA builds asteroid capture mission definitions
« Reply #41 on: 04/03/2014 08:44 AM »
Two related questions:

1. What is the expected SCIENCE return from this retrieval mission? Bringing back a rock to analyze does not really count because learning anything new about the rock beyond what spectral analysis shows is highly unlikely.
2. Assuming there is a real science return, is it worth it in terms of the cost of getting it?
 
I have yet to see this question directly answered.
If pure science were the justification, which I infer from the capitalization, I would count that as a huge mark against it. Planetary Science already has a budget and a very detailed methodology for choosing missions.

I think it is really unfortunate that NASA cannot seem to do precursor missions because they neither fall into the camp of 'science', nor provide missions for SLS.

It is probably of very minor interest to science if NEOs contain useful volatiles or can be used for shielding, and this is also why we still have little idea if Phobos or Deimos could be used to provide propellant for return trips despite performing absurdly more difficult Mars mission, and why we have little interest in investigating the lunar poles to investigate the presence or not of water and/or hydrocarbons there before embarking on a highly expensive and specific multi-decade HSF architecture.

I think the science and HSF budgets should be kept totally separate, and the HSF budget should be for gaining the knowledge we need to colonize the solar system.


Offline newpylong

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Re: NASA builds asteroid capture mission definitions
« Reply #42 on: 04/03/2014 01:27 PM »
Two related questions:

1. What is the expected SCIENCE return from this retrieval mission? Bringing back a rock to analyze does not really count because learning anything new about the rock beyond what spectral analysis shows is highly unlikely.
2. Assuming there is a real science return, is it worth it in terms of the cost of getting it?
 
I have yet to see this question directly answered.

This was answered by Gerst in one interview. He said point blank they do not envision science as a primary goal of this mission.

You could consider any expenditures towards a science return a sunk cost.

Offline truth is life

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Re: NASA builds asteroid capture mission definitions
« Reply #43 on: 04/03/2014 02:55 PM »
But still, OSIRIS-REx has a total cost of about $1 billion. If I had to guess, I'd say the asteroid return is probably worth a good two OSIRIS-RExes, so maybe about $2 billion. Not enough to justify the whole expense, but perhaps enough to justify the cost of the unmanned capture vehicle itself.

But I asked about the "mission", not just the capture spacecraft. To get mission cost you have to add the cost of the SLS HLV launch vehicle and the cost of the launch. That totals quite a but more than $2b total. That's where I'm going with this. That is a lot of money for a single mission. Can this be done with a different, less expensive vehicle, say a Falcon Heavy or a Delta IV Heavy for example? At least then there is an effort to contain costs instead of finding a mission for a seldom used HLV.
Well, it made more sense when it was going to be part of EM-2, hence also an engineering mission, where it would be a clever way to get some science in as well. Very much like the point of NEA rendezvous missions or Mars orbital missions, in fact, where the primary purpose is to test the spacecraft in a relevant environment and under realistic conditions, while having objectives that are less demanding than the "real" objectives you're after (ie., Mars). Here, it would mean that rather than just orbiting the Moon, which would have little value beyond engineering, you also get some nice science done as well.

With the switch to it not being EM-2, that justification has weakened...

Offline Proponent

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Re: NASA builds asteroid capture mission definitions
« Reply #44 on: 04/03/2014 03:43 PM »
How much additional delta V would the system need to have in order to bring the asteroid back to the ISS instead of dropping it off at the current planned orbit? Would a refueling mission be enough extra prop to bring it down low.

After all, they are not talking about a big, dangerous asteroid. Of course I know it all depends on the mass of the captured asteroid.

Assuming you could do a slingshot off the moon on the way in to kill off most of the speed at a lunar distance, the 'roid would be whizzing along at about escape speed (11 km/s) when it reached ISS's altitude.  So the delta-V to circularize at that altitude would be at least 3-ish km/s, which is significant.  And that's just a lower bound.

But a major justification for putting the asteroid in a stable lunar orbit was to ensure it didn't crash into earth if anything went wrong, so presumably bringing the 'roid to ISS is out of the question.

And a major justification for the whole thing is to give Orion a destination.  If the 'roid delivers itself to ISS, there's no longer any need for Orion.

Online notsorandom

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Re: NASA builds asteroid capture mission definitions
« Reply #45 on: 04/03/2014 04:14 PM »
This would be in 2024, ten years from now. Several year long stints at ISS would have been completed. Also this would be ten years after EFT-1.

The first year-long mission at the ISS isn't planned to start until 2015.  However what you appear to be assuming is that any issues that come up in the tests are able to be addressed and retested enough times to ensure that they have been solved.  That might happen, but it might not.  Depends on what they find, and it depends on how fast the solutions get funded, built, flown up to the ISS and the testing can be done.  Lot of "ifs".

This is why assuming we're ready to pull the trigger on an HLV-based human exploration program is premature, since we have not yet figured out what our limits are for humans beyond 6-month stints in LEO.

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Should be long enough to have figured the heat shield out.

As of today, with the heatshield that is not capable enough of coming back from locations beyond the Moon, the MPCV is overweight.  At a NASA news conference last year (don't remember the date) NASA was asked when the MPCV weight issue would be solved, and NASA said they thought they would be fighting it up till the first crew launch (i.e. EM-2).

No doubt that could be addressed faster if more funding was made available, but then you'd have to throw in the additional funding to change out the heatshield for a more robust one.  If a mission was identified that required the MPCV to return from beyond the Moon, I'm sure NASA would be identifying this issue as needing funding, but so far Congress and NASA haven't been discussing funding any missions at all beyond LEO.  I'd rank it as a low probability at this point...
All of the political players in space flight view Mars as the eventual goal. This means that long duration BEO spaceflight is a nut that has to be cracked sooner or later. There are cosmonauts that have in their careers received an equivalent radiation dose of a trip to Mars. We just don't have a big enough sample pool to retire the risk yet. Spending a year in space is doable and all that is required to get to a lot of the NEOs.

The heat shield thing is in the same basket. There may be a lot of margin in the design. We just don't know right now and are being conservative. Even if it requires work and money to fix it we will have to do it eventually. There are numerous good reasons why having the crew vehicle being able to enter directly from an Earth Mars transfer.  By 2024 I don't think it is unrealistic to say that we will have a handle on both issues. After all if we don't by that time then Mars in the 2030s is a pipe dream.

Offline Coastal Ron

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Re: NASA builds asteroid capture mission definitions
« Reply #46 on: 04/03/2014 04:46 PM »
All of the political players in space flight view Mars as the eventual goal. This means that long duration BEO spaceflight is a nut that has to be cracked sooner or later.

Agreed.  And doing the initial testing at the ISS makes a lot of sense since it can happen quicker and for a much lower cost than building new hardware.  It doesn't address the radiation aspect, but that is only one of the factors anyways.

The point I was making, and maybe it wasn't worded right, is that there seems to be two approaches that can be taken.

One is to focus on the issues limiting us from longer duration HSF missions beyond LEO, and keep reassessing if we're ready to move out into space in a larger way.  This is not unlike the capabilities-based planning that NASA is taking with the SLS and MPCV, but it would be based on not the transportation side but the payload side - are we ready to send humans beyond LEO for long durations?  At some point our period assessments will tell us that we're either there are close enough to recommend that missions be approved.  Call this a bottoms-up approach.

The other is to pick a date and hope that we can solve all the problems in time to make that date.  The 2024 date seems like that kind of approach to me, especially since there is no defined need driving that date - it's just a date.  If everything works out then the mission gets to go, but if things don't go as planned there is a whole lot of disconnected efforts that get thrown into disarray.  Call this the top-down approach.

Without an agreed upon need, the top-down approach doesn't make sense, and it won't work because not everyone will be pushing to the same date, and there is likely to be a large funding mismatch.  That's essentially what we have today.

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The heat shield thing is in the same basket. There may be a lot of margin in the design. We just don't know right now and are being conservative.

I'm sure there is already a thread on this, and I'm not an engineer.  But NASA agrees they have a major weight issue with the current specs and that it won't be solved for possibly 7 years.  That doesn't sound like they have margin in the design.

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Even if it requires work and money to fix it we will have to do it eventually.

Or re-evaluate what our future needs are and spend new money to build that.  Let's remember that the MPCV is the product of a political process to "save" elements from the Moon-oriented Constellation program.  If it is marginal for the Moon, why try to use it for beyond the Moon?  I think we're already at the point that we need to be working on the next step in space transportation, which will have to be mostly reusable if we're ever going to afford to increase our presence in space.

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After all if we don't by that time then Mars in the 2030s is a pipe dream.

It is a pipe dream.  If we're struggling to meet up with a small rock just beyond the Moon in 10 years, why in the world would you think we'll be ready to go to Mars in another 10 years?

I'm not sure you understand how little NASA is able to do, and how much is needed to be done to get to Mars.
If we don't continuously lower the cost to access space, how are we ever going to afford to expand humanity out into space?

Offline MP99

Re: NASA builds asteroid capture mission definitions
« Reply #47 on: 04/03/2014 06:59 PM »
Quote
... NASA is aggressively pursuing to ARRM concept and has demonstrated that there are no technological roadblocks to implementation.

The key technologies necessary to implement this mission -- high-power SEP, the deep space rendezvous system, the capture mechanism, and the despin procedure -- have yet to be demonstrated at any level.  High-level, generic analyses don't count as demonstrations.  It's impossible to state at this time that there are "no technological roadblocks".  Until we get further into actual development -- and possibly not until the mission is over -- will we know whether there are "no technological roadblocks" to ARM.

Aren't those things which will be demonstrated *by* the mission?

cheers, Martin

Offline veblen

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Re: NASA builds asteroid capture mission definitions
« Reply #48 on: 04/03/2014 07:44 PM »
Good article, stupid mission. Does not capture public imagination, will end up in the pile of powerpoints on the side of the road after the next budget cut.


Cute cat vids are popular. Kittys in micro-gravity would be hysterical and I dare say, "capture public imagination". Is that a good basis for designing space missions?

For a purely commercial mission, yes. NASA, of course, is where the pre-commercial stuff is supposed to get done. Unfortunately, their funding comes from the public purse, so unless there's enough level of public engagement to get Congress' attention, missions will die, like Apollo did.

My concern is that this mission makes no sense. If you're going to robotically fetch a big rock, why leave it way out there where you then have to stage an expensive manned mission to have astronauts crawl all over it? Wouldn't it make more sense to bring it to the ISS? Or, since the mission has turned from exploration to studying rocks, why not just look at the pieces of asteroids that have voluntarily come to Earth?

Real manned asteroid exploration is getting into a spacecraft and going out to an asteroid. That's a mission that would get peoples' interest.



Well it has been discussed on this board the issue for a crew going out to an asteroid: Delta-v - asteroids are challenging targets. The ISS is not equipped to study a chunk of an asteroid.




Offline KelvinZero

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Re: NASA builds asteroid capture mission definitions
« Reply #49 on: 04/04/2014 08:44 AM »
Good article, stupid mission. Does not capture public imagination, will end up in the pile of powerpoints on the side of the road after the next budget cut.


Cute cat vids are popular. Kittys in micro-gravity would be hysterical and I dare say, "capture public imagination". Is that a good basis for designing space missions?
Man.. you are going to really regret not patenting that idea. LEOLOLCats.

Online Vultur

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Re: NASA builds asteroid capture mission definitions
« Reply #50 on: 04/05/2014 02:35 AM »
Good article, stupid mission. Does not capture public imagination, will end up in the pile of powerpoints on the side of the road after the next budget cut.


Cute cat vids are popular. Kittys in micro-gravity would be hysterical and I dare say, "capture public imagination". Is that a good basis for designing space missions?
Man.. you are going to really regret not patenting that idea. LEOLOLCats.

Possibly deserves its own thread  ;)


This would be in 2024, ten years from now. Several year long stints at ISS would have been completed. Also this would be ten years after EFT-1.

The first year-long mission at the ISS isn't planned to start until 2015.  However what you appear to be assuming is that any issues that come up in the tests are able to be addressed and retested enough times to ensure that they have been solved.  That might happen, but it might not.  Depends on what they find, and it depends on how fast the solutions get funded, built, flown up to the ISS and the testing can be done.  Lot of "ifs".

This is why assuming we're ready to pull the trigger on an HLV-based human exploration program is premature, since we have not yet figured out what our limits are for humans beyond 6-month stints in LEO.

Well, humans have spent much more than 6 months in LEO -- record is over 14 months ( http://en.wikipedia.org/wiki/Valeri_Polyakov )

Offline A_M_Swallow

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Re: NASA builds asteroid capture mission definitions
« Reply #51 on: 04/05/2014 05:46 PM »

But I asked about the "mission", not just the capture spacecraft. To get mission cost you have to add the cost of the SLS HLV launch vehicle and the cost of the launch. That totals quite a but more than $2b total. That's where I'm going with this. That is a lot of money for a single mission. Can this be done with a different, less expensive vehicle, say a Falcon Heavy or a Delta IV Heavy for example? At least then there is an effort to contain costs instead of finding a mission for a seldom used HLV.

The Falcon Heavy can launch an Orion to LEO but then an inspace stage is needed to supply the 3.77 km/s delta-v needed to go from LEO to EML-1.

Offline IRobot

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Re: NASA builds asteroid capture mission definitions
« Reply #52 on: 04/05/2014 09:25 PM »

But I asked about the "mission", not just the capture spacecraft. To get mission cost you have to add the cost of the SLS HLV launch vehicle and the cost of the launch. That totals quite a but more than $2b total. That's where I'm going with this. That is a lot of money for a single mission. Can this be done with a different, less expensive vehicle, say a Falcon Heavy or a Delta IV Heavy for example? At least then there is an effort to contain costs instead of finding a mission for a seldom used HLV.

The Falcon Heavy can launch an Orion to LEO but then an inspace stage is needed to supply the 3.77 km/s delta-v needed to go from LEO to EML-1.
The Orion service module has a delta-v of 1600m/s.

Also, at 22mT, the Falcon Heavy can put it on much higher orbit than LEO. Still, it might not be enough, because you need to add the EML-1 to earth delta-v.

Offline A_M_Swallow

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Re: NASA builds asteroid capture mission definitions
« Reply #53 on: 04/06/2014 02:00 AM »

But I asked about the "mission", not just the capture spacecraft. To get mission cost you have to add the cost of the SLS HLV launch vehicle and the cost of the launch. That totals quite a but more than $2b total. That's where I'm going with this. That is a lot of money for a single mission. Can this be done with a different, less expensive vehicle, say a Falcon Heavy or a Delta IV Heavy for example? At least then there is an effort to contain costs instead of finding a mission for a seldom used HLV.

The Falcon Heavy can launch an Orion to LEO but then an inspace stage is needed to supply the 3.77 km/s delta-v needed to go from LEO to EML-1.
The Orion service module has a delta-v of 1600m/s.

Also, at 22mT, the Falcon Heavy can put it on much higher orbit than LEO. Still, it might not be enough, because you need to add the EML-1 to earth delta-v.

If you are doing a reentry the EML-1 to Earth surface delta-v is about 0.77 km/s.

The inspace stage could be launched separately from the Orion and the pair dock in orbit.

The quantity of thrust needed to push the spacecraft to EML-1 and for how long the burn is may determine if an existing engine (or group of engines) can be used or cause a new engine to be designed.

Offline newpylong

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Re: NASA builds asteroid capture mission definitions
« Reply #54 on: 04/06/2014 03:47 PM »

But I asked about the "mission", not just the capture spacecraft. To get mission cost you have to add the cost of the SLS HLV launch vehicle and the cost of the launch. That totals quite a but more than $2b total. That's where I'm going with this. That is a lot of money for a single mission. Can this be done with a different, less expensive vehicle, say a Falcon Heavy or a Delta IV Heavy for example? At least then there is an effort to contain costs instead of finding a mission for a seldom used HLV.

The Falcon Heavy can launch an Orion to LEO but then an inspace stage is needed to supply the 3.77 km/s delta-v needed to go from LEO to EML-1.
The Orion service module has a delta-v of 1600m/s.

Also, at 22mT, the Falcon Heavy can put it on much higher orbit than LEO. Still, it might not be enough, because you need to add the EML-1 to earth delta-v.

How are they going to get home if Orion uses its Main engine for T-EML1 injection? That burn needs to be achieved using a cryogenic stage.

Offline A_M_Swallow

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Re: NASA builds asteroid capture mission definitions
« Reply #55 on: 04/07/2014 02:10 AM »

But I asked about the "mission", not just the capture spacecraft. To get mission cost you have to add the cost of the SLS HLV launch vehicle and the cost of the launch. That totals quite a but more than $2b total. That's where I'm going with this. That is a lot of money for a single mission. Can this be done with a different, less expensive vehicle, say a Falcon Heavy or a Delta IV Heavy for example? At least then there is an effort to contain costs instead of finding a mission for a seldom used HLV.

The Falcon Heavy can launch an Orion to LEO but then an inspace stage is needed to supply the 3.77 km/s delta-v needed to go from LEO to EML-1.
The Orion service module has a delta-v of 1600m/s.

Also, at 22mT, the Falcon Heavy can put it on much higher orbit than LEO. Still, it might not be enough, because you need to add the EML-1 to earth delta-v.

How are they going to get home if Orion uses its Main engine for T-EML1 injection? That burn needs to be achieved using a cryogenic stage.

To perform the return burn the Orion needs a main engine that can be restarted inspace whose propellant is space storable such as LOX/methane.  A medium sized Isp just means that the tanks have to be big.  Fortunately nearly empty fuel tanks are light.

Quote
The quantity of thrust needed to push the spacecraft to EML-1 and for how long the burn is may determine if an existing engine (or group of engines) can be used or cause a new engine to be designed.

Offline Robert Thompson

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Re: NASA builds asteroid capture mission definitions
« Reply #56 on: 04/07/2014 08:17 AM »
"...the principle of construction of Makarovís cable networks can be the basis for creating a huge space platform. On such a platform, a solar reflector could be placed that directs concentrated sunlight to the asteroid Apophis in order to change its trajectory. This will prevent it  from colliding with Earth in 2029."

http://www.spacesafetymagazine.com/2014/04/04/modern-dreams-sky-earth/

Offline newpylong

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Re: NASA builds asteroid capture mission definitions
« Reply #57 on: 04/07/2014 10:48 AM »

But I asked about the "mission", not just the capture spacecraft. To get mission cost you have to add the cost of the SLS HLV launch vehicle and the cost of the launch. That totals quite a but more than $2b total. That's where I'm going with this. That is a lot of money for a single mission. Can this be done with a different, less expensive vehicle, say a Falcon Heavy or a Delta IV Heavy for example? At least then there is an effort to contain costs instead of finding a mission for a seldom used HLV.

The Falcon Heavy can launch an Orion to LEO but then an inspace stage is needed to supply the 3.77 km/s delta-v needed to go from LEO to EML-1.
The Orion service module has a delta-v of 1600m/s.

Also, at 22mT, the Falcon Heavy can put it on much higher orbit than LEO. Still, it might not be enough, because you need to add the EML-1 to earth delta-v.

How are they going to get home if Orion uses its Main engine for T-EML1 injection? That burn needs to be achieved using a cryogenic stage.

To perform the return burn the Orion needs a main engine that can be restarted inspace whose propellant is space storable such as LOX/methane.  A medium sized Isp just means that the tanks have to be big.  Fortunately nearly empty fuel tanks are light.

Quote
The quantity of thrust needed to push the spacecraft to EML-1 and for how long the burn is may determine if an existing engine (or group of engines) can be used or cause a new engine to be designed.

Ya didn't get what I meant. If the Orion SPS is used to get out of earth orbit it will most likely not have enough propellant to make the return burn.

It does have storable propellant and a restartable main engine.

Offline A_M_Swallow

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Re: NASA builds asteroid capture mission definitions
« Reply #58 on: 04/07/2014 08:47 PM »

Ya didn't get what I meant. If the Orion SPS is used to get out of earth orbit it will most likely not have enough propellant to make the return burn.

It does have storable propellant and a restartable main engine.

Then the Orion Service Module will either need larger fuel tanks for the return trip to EML-1 or to refuel.  The extra work and cost of handling the fuel will need planning in.

Offline Jim

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Re: NASA builds asteroid capture mission definitions
« Reply #59 on: 04/07/2014 11:19 PM »

Then the Orion Service Module will either need larger fuel tanks for the return trip to EML-1 or to refuel.  The extra work and cost of handling the fuel will need planning in.

No, neither are in the plans

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