Author Topic: Proposed Europa Missions  (Read 641092 times)

Offline spectre9

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Re: Proposed Europa Missions
« Reply #140 on: 07/26/2013 02:46 am »
Thanks Blackstar. You're a champion.

Cool new stacked design. Makes sense.

I'm excited about the close up shots with the recon camera.  :)

All this time being taken to refine the mission seems to be paying off. The science objectives, the mission con ops, the spacecraft design.

I like how the stacked design allows it to be built in segments and then plugged together. Hopefully this modular approach creates a better funding profile.

Which module first? The avionics module with the vault? I assume the lower propulsion module will be last as the ASRGs will not be available for a while.

Seems like the orbit has possible encounters for Callisto and Ganymede. Might be an option for an extended mission if there's extra power.

Offline EE Scott

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Re: Proposed Europa Missions
« Reply #141 on: 07/26/2013 03:28 am »
So exciting the possibility, so remote the chance.  Still I'll allow myself to believe it could happen.
Scott

Offline Blackstar

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Re: Proposed Europa Missions
« Reply #142 on: 07/26/2013 12:48 pm »
I think that the likely power source would be an MMRTG. NASA is building another one for Mars 2020, which maintains the experience/production base.

NASA is building/has built (my guess is that they are majority complete) two ASRG units that will be placed in "bonded storage" (what the heck does "bonded" mean in this context?). The problem is that the ASRGs would not be flight proven before this mission would enter build phase--although who knows when that will be? So I think that NASA would take the most conservative option and go with the MMRTG for a multi-billion dollar mission.
« Last Edit: 07/26/2013 12:52 pm by Blackstar »

Offline robertross

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Re: Proposed Europa Missions
« Reply #143 on: 07/26/2013 12:54 pm »

NASA is building/has built (my guess is that they are majority complete) two ASRG units that will be placed in "bonded storage" (what the heck does "bonded" mean in this context?).


Just 'secure' I beleive, but perhaps even with armed security. We see a lot of that here in Halifax with all the container traffic.

Offline Zed_Noir

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Re: Proposed Europa Missions
« Reply #144 on: 07/26/2013 07:37 pm »
NASA is building/has built (my guess is that they are majority complete) two ASRG units that will be placed in "bonded storage" (what the heck does "bonded" mean in this context?). The problem is that the ASRGs would not be flight proven before this mission would enter build phase--although who knows when that will be?


Maybe they can test fly the ASRG unit and recover it for refueling with a space capsule.

Offline EE Scott

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Re: Proposed Europa Missions
« Reply #145 on: 07/26/2013 07:44 pm »
I think that the likely power source would be an MMRTG. NASA is building another one for Mars 2020, which maintains the experience/production base.

NASA is building/has built (my guess is that they are majority complete) two ASRG units that will be placed in "bonded storage" (what the heck does "bonded" mean in this context?). The problem is that the ASRGs would not be flight proven before this mission would enter build phase--although who knows when that will be? So I think that NASA would take the most conservative option and go with the MMRTG for a multi-billion dollar mission.


Any idea what (or when) the first ASRG-equipped mission might be? 

Someone's got to step up and just do it so we can get a better idea of its true performance potential.
Scott

Offline Blackstar

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Re: Proposed Europa Missions
« Reply #146 on: 07/26/2013 08:44 pm »
Maybe they can test fly the ASRG unit and recover it for refueling with a space capsule.


No.

Offline Blackstar

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Re: Proposed Europa Missions
« Reply #147 on: 07/26/2013 08:47 pm »
Any idea what (or when) the first ASRG-equipped mission might be? 

Someone's got to step up and just do it so we can get a better idea of its true performance potential.

The next real opportunity will be with the next Discovery or New Frontiers selection. I think that the next Discovery selection is not slated to happen before 2016 and the next New Frontiers before 2017 or so. But both are going to slip because of ongoing budget cuts. And even if such a mission was selected, it would take five or more years to build the spacecraft, so we won't see an ASRG mission fly in this decade.

The last Discovery selection included three potential missions. Two required ASRGs and the third was conventional. That one, InSight, was selected, probably because it was the least risky of the three missions.

There are people inside of NASA who were pushing for an ASRG mission, but they did not win out.

Offline Blackstar

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Re: Proposed Europa Missions
« Reply #148 on: 07/26/2013 08:49 pm »

NASA is building/has built (my guess is that they are majority complete) two ASRG units that will be placed in "bonded storage" (what the heck does "bonded" mean in this context?).


Just 'secure' I beleive, but perhaps even with armed security. We see a lot of that here in Halifax with all the container traffic.

I'm guessing that it means storage in clean-room/controlled conditions, as opposed to being stuck in a warehouse. NASA kept the DSCOVR spacecraft in a temp and humidity controlled container at Goddard for many years, I believe, before retrieving it for refurbishment.

Offline robertross

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Re: Proposed Europa Missions
« Reply #149 on: 07/27/2013 12:44 am »

NASA is building/has built (my guess is that they are majority complete) two ASRG units that will be placed in "bonded storage" (what the heck does "bonded" mean in this context?).


Just 'secure' I beleive, but perhaps even with armed security. We see a lot of that here in Halifax with all the container traffic.

I'm guessing that it means storage in clean-room/controlled conditions, as opposed to being stuck in a warehouse. NASA kept the DSCOVR spacecraft in a temp and humidity controlled container at Goddard for many years, I believe, before retrieving it for refurbishment.

not the typical definition of bonded storage; it would need to state that explicitely (or be clean room/controlled by default with the added feature of being in bonded storage).

Bonded is essentially lock & key with tamperproof features to ensure no tampering is possible without someone knowing about it.

Offline Blackstar

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Re: Proposed Europa Missions
« Reply #150 on: 07/27/2013 02:36 am »
not the typical definition of bonded storage; it would need to state that explicitely (or be clean room/controlled by default with the added feature of being in bonded storage).

Bonded is essentially lock & key with tamperproof features to ensure no tampering is possible without someone knowing about it.

Well, I'm presuming that because it is nuclear-related materials that there are certain restrictions applied to it. So, yeah, locked up, but probably also environmentally controlled as well.

On a tangentially-related note, I heard a story several years ago from a now-former NASA official about the remaining supply of Neptunium that would be used to create Pu-238 fuel. Apparently this guy ordered a NASA official to go and slap NASA inventory numbers on the containers filled with this fuel. He didn't want some DoE person to come along and assume that it was just DoE material and discard it. I'm sure that he did something, but I found the story to be a little hard to compute, because I'm pretty sure that NASA does not own that material and in fact is probably not allowed under law to own it, so I don't know how NASA could label it. But it's in a secure DoE warehouse somewhere, probably next to the Ark of the Covenant and Jimmy Hoffa's frozen corpse.

Offline EE Scott

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Re: Proposed Europa Missions
« Reply #151 on: 07/27/2013 02:59 am »
Any idea what (or when) the first ASRG-equipped mission might be? 

Someone's got to step up and just do it so we can get a better idea of its true performance potential.

The next real opportunity will be with the next Discovery or New Frontiers selection. I think that the next Discovery selection is not slated to happen before 2016 and the next New Frontiers before 2017 or so. But both are going to slip because of ongoing budget cuts. And even if such a mission was selected, it would take five or more years to build the spacecraft, so we won't see an ASRG mission fly in this decade.

The last Discovery selection included three potential missions. Two required ASRGs and the third was conventional. That one, InSight, was selected, probably because it was the least risky of the three missions.

There are people inside of NASA who were pushing for an ASRG mission, but they did not win out.

Thanks for your thoughts on this.  The pace of progress is maddening to me.  There are so many promising ways to stretch resources, like ASRG, or aero capture/braking, etc.  But if we don't fly the first mission to try out these new technologies and techniques, we are stuck with the same capabilities.  I guess we don't even have the budget to choose a decent amount of conventional mission profiles, let alone something that pushes the boundaries.

Scott

Offline Blackstar

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Re: Proposed Europa Missions
« Reply #152 on: 07/27/2013 02:01 pm »
The pace of progress is maddening to me.  There are so many promising ways to stretch resources, like ASRG, or aero capture/braking, etc.  But if we don't fly the first mission to try out these new technologies and techniques, we are stuck with the same capabilities.  I guess we don't even have the budget to choose a decent amount of conventional mission profiles, let alone something that pushes the boundaries.



With the Discovery program NASA had three mission options:

-TiME (Titan lake lander), ASRG, probably the most expensive of the missions
-Comet Hopper, ASRG, probably medium expensive
-InSight, Mars lander, solar panels, proven hardware

When I say "expensive," you have to understand that Discovery is cost-capped. That means that technically, all three mission proposals cost the same (~$475 million, I think). But TiME and Comet Hopper were more likely to go over budget than InSight.

When we say that we want NASA to take more risk, we also need to understand that we (or Congress, people in general) are just as likely to criticize those decision-makers when things don't go perfectly. So when TiME went over budget, people would complain and call for the leadership to be punished/fired, etc.

In addition, NASA's planetary budget was going down. In that environment, the safest course of action is to pick the cheapest mission, or at least the one that is unlikely to bust its cost cap.

Offline EE Scott

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Re: Proposed Europa Missions
« Reply #153 on: 07/29/2013 01:49 am »
The pace of progress is maddening to me.  There are so many promising ways to stretch resources, like ASRG, or aero capture/braking, etc.  But if we don't fly the first mission to try out these new technologies and techniques, we are stuck with the same capabilities.  I guess we don't even have the budget to choose a decent amount of conventional mission profiles, let alone something that pushes the boundaries.



With the Discovery program NASA had three mission options:

-TiME (Titan lake lander), ASRG, probably the most expensive of the missions
-Comet Hopper, ASRG, probably medium expensive
-InSight, Mars lander, solar panels, proven hardware

When I say "expensive," you have to understand that Discovery is cost-capped. That means that technically, all three mission proposals cost the same (~$475 million, I think). But TiME and Comet Hopper were more likely to go over budget than InSight.

When we say that we want NASA to take more risk, we also need to understand that we (or Congress, people in general) are just as likely to criticize those decision-makers when things don't go perfectly. So when TiME went over budget, people would complain and call for the leadership to be punished/fired, etc.

In addition, NASA's planetary budget was going down. In that environment, the safest course of action is to pick the cheapest mission, or at least the one that is unlikely to bust its cost cap.

Yes.  In this budget environment, I should just be happy if we can get conservative missions funded. Even though I would love to see TiME chosen as a bonus mission (Senate proposal), or this Europa mission become reality. Because if there is some strange way the SLS fiasco could somehow be of use, because they are desperate  for missions/payloads using SLS, that would be a consolation.
« Last Edit: 07/29/2013 01:52 am by EE Scott »
Scott

Offline Blackstar

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Re: Proposed Europa Missions
« Reply #154 on: 07/29/2013 07:07 pm »
http://thespacereview.com/article/2338/1



Talk of an icy moon at Vegas for Nerds
by Dwayne Day
Monday, July 29, 2013

Every July a hundred and thirty thousand people descend upon San Diego for Comic-Con, an event best described as “Las Vegas for nerds.” There are thousands of events that take place both inside and outside the San Diego Convention Center over four days, some exclusive, some open to anybody who walks in. One of the more difficult to reach venues is the convention center’s Hall H, which can seat more than 6,000 people, and is the stage for most of the biggest-hyped and popular panels at Comic-Con, such as the ones where major Hollywood movies are rolled out and big name movie stars and directors unveil their new productions. Getting into Hall H often requires standing in line for many hours starting out in the early morning, or even sleeping on the lawn outside the Convention Center overnight—something you can do in your teens and twenties, but can strain the backs of people older than that. In all my years of going to Comic-Con I’ve never tried to get into Hall H, but last week Thursday I gave it a shot and easily got into the panel for the new movie Europa Report. The movie premieres in theaters August 2, but is already available via download or on demand (see “Life and death and ice”, The Space Review, July 1, 2013).

Offline simonbp

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Re: Proposed Europa Missions
« Reply #155 on: 07/29/2013 08:29 pm »
With the Discovery program NASA had three mission options:

-TiME (Titan lake lander), ASRG, probably the most expensive of the missions
-Comet Hopper, ASRG, probably medium expensive
-InSight, Mars lander, solar panels, proven hardware

From the scuttlebutt around the time of the decision, it sounded like the breakdown was more:

- TiME: Low technical risk (essentially a reflight of Huygens hardware with an added ASRG), high science risk (not much data returned, risk of landing somewhere where the terrain impedes downlink).

- Comet Hopper: High technical risk (no one has ever landed on an comet), low science risk (no one has ever landed on an comet, anything is new)

- Insight: Low technical risk (Phoenix reflight), low science risk (it will return data, just not necessarily high-priority data)

Based on that, Insight had the lowest technical and science risk, and therefore was least likely to go overbudget. Plus, it's not a confidence that they announced Insight shortly after MSL landed...

For Europa, IMHO that means that the solar option may come to the fore. Assuming the solar arrays on Juno work well (and keeping in mind its periapse is much closer to Jupiter than Io), the JPL margin on them may come down enough that they are similar mass to the RTGs (and still lowest cost).

Offline Blackstar

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Re: Proposed Europa Missions
« Reply #156 on: 07/29/2013 08:40 pm »
- TiME: Low technical risk (essentially a reflight of Huygens hardware with an added ASRG)

I have a hard time believing that it was a reflight of Huygens hardware. For starters, this was a U.S. mission and Huygens was built by ESA. But I know somebody who was on TiME and Huygens and can ask him.

Offline arachnitect

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Re: Proposed Europa Missions
« Reply #157 on: 07/30/2013 01:22 am »

Based on that, Insight had the lowest technical and science risk, and therefore was least likely to go overbudget. Plus, it's not a confidence that they announced Insight shortly after MSL landed...


IIRC, they had already made the decision before MSL reached mars and were sitting on it so that the Discovery announcement wouldn't get lost in the MSL excitement.

When they explained the selection, I got the impression that the science return from all 3 proposals was considered very good and technical maturity/low risk alone sealed the deal for InSight.

Offline Blackstar

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Re: Proposed Europa Missions
« Reply #158 on: 07/30/2013 01:27 am »
I got the impression that the science return from all 3 proposals was considered very good and technical maturity/low risk alone sealed the deal for InSight.

There's a challenge with that. How do we rate the science return? According to NASA, the science return for all three missions was rated as "high," and therefore they were equal in terms of science. I know a highly respected space scientist who thought that all three were high value science missions.

But the value of that science also depends upon who is doing the valuing. I think that seismology is not rated highly by many scientists because they consider it to be narrow. So even though InSight would be the first seismic data from Mars, I don't think many scientists care. The flip side is that although we've never actually sampled a comet's surface, the group of scientists interested in primitive bodies like comets is isolated from the group that is interested in things like Mars habitability.

So it's not easy to make these comparisons.

Offline neveroddoreven

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Re: Proposed Europa Missions
« Reply #159 on: 07/30/2013 03:49 pm »
So, currently the notional launch vehicle for this clipper would be the Atlas V 551. Using this vehicle the thing would have to use a VEEGA trajectory and end up taking six and a half years to get to Europa. Then they are talking about SLS as an alternative which would enable a direct route that would take less than 2 years, but we all know that them using SLS on this mission is unlikely. Well, looking at Falcon Heavy's new payload to GTO of 21,200 kg (relative to 551's 8,700kg) and payload to Mars of 13,500 kg (not sure what 551's is here, but I'm assuming significantly lower) I was wondering if it would be a feasible option as well. Would it be capable of a direct route like SLS or would it not have the power? If direct isn't possible could you use a trajectory different than VEEGA like VEGA or VGA to cut down on time or would the position of the planets not allow for such a trajectory?

On top of a possibly shorter trip Falcon Heavy would be significantly cheaper as well. They are listing it as costing $133 million whereas wiki says the 541 (couldn't find a price for the 551) is $223 million.

 

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