Quote from: Robotbeat on 04/02/2014 10:52 pmBut 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.
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.
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.
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.
Quote from: notsorandom on 04/02/2014 08:30 pmThis 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.QuoteShould 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...
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.
Should be long enough to have figured the heat shield out.
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.
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.
After all if we don't by that time then Mars in the 2030s is a pipe dream.
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.
... NASA is aggressively pursuing to ARRM concept and has demonstrated that there are no technological roadblocks to implementation.
Quote from: veblen on 04/01/2014 05:42 pmQuote from: laszlo on 04/01/2014 02:49 pmGood 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.
Quote from: laszlo on 04/01/2014 02:49 pmGood 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?
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.
Quote from: veblen on 04/01/2014 05:42 pmQuote from: laszlo on 04/01/2014 02:49 pmGood 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.
Quote from: notsorandom on 04/02/2014 08:30 pmThis 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.
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.
Quote from: clongton on 04/02/2014 11:48 pmBut 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.
Quote from: A_M_Swallow on 04/05/2014 05:46 pmQuote from: clongton on 04/02/2014 11:48 pmBut 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.
Quote from: IRobot on 04/05/2014 09:25 pmQuote from: A_M_Swallow on 04/05/2014 05:46 pmQuote from: clongton on 04/02/2014 11:48 pmBut 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.
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.
Quote from: newpylong on 04/06/2014 03:47 pmQuote from: IRobot on 04/05/2014 09:25 pmQuote from: A_M_Swallow on 04/05/2014 05:46 pmQuote from: clongton on 04/02/2014 11:48 pmBut 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.QuoteThe 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.
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.