hektor - 29/11/2006 11:42 AMI fear you are forgetting that the Moon rotates around the Earth.The orbit of the ISS is suitable for a Lunar mission, provided you accept to wait for the Moon to be in the orbital plane of the ISS, which happens twice a month if I am not mistaken. This create an operational constraint on the date when you perform the TLI, but I think this is acceptable.I am not even sure that the delta-V penalty not to launch precisely when the Moon is in the ISS plane is that large, maybe somebody here knows ?
hektor - 29/11/2006 3:36 PMAbsolutely not, you are reasoning in 2-D. Think 3D take a ball and a piece of cardboard if you want to check, but when the Moon is in the ISS plane there is no extra Delta V to provide
hektor - 29/11/2006 2:36 PMAbsolutely not, you are reasoning in 2-D. Think 3D take a ball and a piece of cardboard if you want to check, but when the Moon is in the ISS plane there is no extra Delta V to provide
tom nackid - 29/11/2006 3:25 PMWhat would be the point of using ISS as a "staging area" even if it was in a more suitable orbit? After all its not like ISS is an island where a passing ship can pick up fresh water and a couple of goats! Anything a CEV could get from ISS would still have to have been lifted their in the first place. Going to the moon is not like crossing a desert where you can go part way and leave a supply cache. Its more like crossing a canyon. You can't so it by taking two small jumps!
What's the point of a supply depot in orbit? Everything has to be lifted there to begin with! One big launch is more efficient and lots safer than 10 small launches--at least with the current state of the art.
tom nackid - 29/11/2006 4:03 PMWhat's the point of a supply depot in orbit? Everything has to be lifted there to begin with! One big launch is more efficient and lots safer than 10 small launches--at least with the current state of the art. Von Braun was big on orbital assembly back in the 50's because no one knew how to make large rocket engines and clustering can only take you so far--hence smaller, lower powered boosters were the rule. Constellation will not need anything big enough to require orbital assembly beyond docking the Orion to the lunar insertion stage/LM. No doubt in the future extremely large vehicles for Mars and beyond will need to be asembled in orbit, but again why do it at a space station?
Question: Isn't 70.9mT a little excessive for Crew Launch flights? Answer:No. It is certainly more than enough to lift the 22mT Orion CEV. But, having the ability to also bring up a further 48.9mT of payload creates the option to bring useful cargo up to space with every crew. This is an ability we completely lose otherwise after Shuttle retires. This extra performance is utilized by the Lunar missions, where the Crew Launch brings up a 48mT Lunar Surface Access Module (LSAM). For ISS flights, the Crew Launch can bring up large quantities of spares & supplies, for no extra cost. It could even bring up sections of the ISS which have been cancelled due to the Shuttle's retirement, such as: Centrifuge Accommodations Module Habitation Module ISS Propulsion Module Science Power Platform
Bill White - 29/11/2006 11:27 PMDennis, if you are correct (and I will assume you are) then the Direct architecture suggested elsewhere at this site would allow us the opportunity to both sustain ISS and begin Moon, Mars and Beyond within the same overall budgetary envelope.For those unfamilar with Direct, a link:http://www.directlauncher.com/The plan proposes to launch CEV on a booster capable of lofting 70.9 mT to LEO. From the FAQ:QuoteQuestion: Isn't 70.9mT a little excessive for Crew Launch flights? Answer:No. It is certainly more than enough to lift the 22mT Orion CEV. But, having the ability to also bring up a further 48.9mT of payload creates the option to bring useful cargo up to space with every crew. This is an ability we completely lose otherwise after Shuttle retires. This extra performance is utilized by the Lunar missions, where the Crew Launch brings up a 48mT Lunar Surface Access Module (LSAM). For ISS flights, the Crew Launch can bring up large quantities of spares & supplies, for no extra cost. It could even bring up sections of the ISS which have been cancelled due to the Shuttle's retirement, such as: Centrifuge Accommodations Module Habitation Module ISS Propulsion Module Science Power Platform I would propose a combination of Direct with a lighter smaller non-CEV crew taxi chosen via competition between RpK, SpaceX and Atlas V.
Stormlordalpha - 30/11/2006 1:53 AMThanks for your replies so far!At another view, I believe it should be possible to go from ISS inclination to the moon. Because the Sovjets had their Zond programm. And their spacecrafts was launched from Baikonur. The question is, 'cause Zond was just circumlunar, if you could go with a Orion or another CEV in a LLO economically.
MKremer - 30/11/2006 2:26 AMActually, any LEO inclination can do a TLI, it just depends on time/mass/orbital parameters/booster used.Don't forget the saying "once you're in Earth orbit, you're halfway to anywhere".
wingod - 30/11/2006 2:00 AMAdd four "SRB's" for heavy payloads and for MARS.
wingod - 29/11/2006 9:42 PMQuotetom nackid - 29/11/2006 4:03 PMWhat's the point of a supply depot in orbit? Everything has to be lifted there to begin with! One big launch is more efficient and lots safer than 10 small launches--at least with the current state of the art. Von Braun was big on orbital assembly back in the 50's because no one knew how to make large rocket engines and clustering can only take you so far--hence smaller, lower powered boosters were the rule. Constellation will not need anything big enough to require orbital assembly beyond docking the Orion to the lunar insertion stage/LM. No doubt in the future extremely large vehicles for Mars and beyond will need to be asembled in orbit, but again why do it at a space station?Two assumptions here.1. More Efficient2. SaferThere is no empirical evidence for either of these theses. I point out again that efficiency by your implied metric would have 747's delivering toys from China to Walmart in Huntsville Alabama (or anywhere else). Yet they use an extremely complex shipping system were a cargo goes through several transportation systems and it is MORE efficient than sending things in one really big load.Safer is an emphemeral concept in this context. It is a value judgement. I could just as easily and with just as much logical support state that a single launch is less safe to the success of the mission due to the ramifications related to a failure of the large launcher. Von Braun, with more experience in multiple launches of payloads than everyone else on the planet combined, stood on firm ground when calling for a lot of launches."Doing" it at a space station has many advantages even beyond what Jon has posited.The first and foremost is that the station has its own attitude control system that is independent of the payloads delivered there. This means that the station can be a platform where these payloads can be passively stored and or assembled in between flights and would require a much less complicated set of hardware than just trying to aggregate payloads at a virtual spot in a random orbit. Second is that if there are any problems in the assembly process there are both humans and robots available to recover from the anomaly/failure. Another feature is that you can build a vehicle for cislunar transportation that has much better volumetric efficiency than the current LSAM. I have already demolished the myth of the much lower payload to orbit to the station in another thread.This is just for starters.
tom nackid - 30/11/2006 8:42 AMQuotewingod - 29/11/2006 9:42 PMQuotetom nackid - 29/11/2006 4:03 PMWhat's the point of a supply depot in orbit? Everything has to be lifted there to begin with! One big launch is more efficient and lots safer than 10 small launches--at least with the current state of the art. Von Braun was big on orbital assembly back in the 50's because no one knew how to make large rocket engines and clustering can only take you so far--hence smaller, lower powered boosters were the rule. Constellation will not need anything big enough to require orbital assembly beyond docking the Orion to the lunar insertion stage/LM. No doubt in the future extremely large vehicles for Mars and beyond will need to be asembled in orbit, but again why do it at a space station?Two assumptions here.1. More Efficient2. SaferThere is no empirical evidence for either of these theses. I point out again that efficiency by your implied metric would have 747's delivering toys from China to Walmart in Huntsville Alabama (or anywhere else). Yet they use an extremely complex shipping system were a cargo goes through several transportation systems and it is MORE efficient than sending things in one really big load.Safer is an emphemeral concept in this context. It is a value judgement. I could just as easily and with just as much logical support state that a single launch is less safe to the success of the mission due to the ramifications related to a failure of the large launcher. Von Braun, with more experience in multiple launches of payloads than everyone else on the planet combined, stood on firm ground when calling for a lot of launches."Doing" it at a space station has many advantages even beyond what Jon has posited.The first and foremost is that the station has its own attitude control system that is independent of the payloads delivered there. This means that the station can be a platform where these payloads can be passively stored and or assembled in between flights and would require a much less complicated set of hardware than just trying to aggregate payloads at a virtual spot in a random orbit. Second is that if there are any problems in the assembly process there are both humans and robots available to recover from the anomaly/failure. Another feature is that you can build a vehicle for cislunar transportation that has much better volumetric efficiency than the current LSAM. I have already demolished the myth of the much lower payload to orbit to the station in another thread.This is just for starters.Wingod, one shipborn cargo container of toys from China holds more than any 747 can handle! That is WHY we send everything but extremely high value goods by ship. Ships can carry an immense amount of cargo per trip compared to planes.As I said I have no doubt that orbital assembly facilities will be important in the coming decades, but for the purposes of Project Constellation building one is more trouble than it is worth. Would you have told Lewis and Clark to put off their exploration until roads had been built into the Louisiana territory? Also the ISS is not designed to be an assembly facility or a supply depot and as has been pointed out is in a poor orbit to act as a staging area for lunar missions.Safety is definitely NOT an "ephemeral concept"! Try getting a shipping insurance policy from Loyds without some hard numbers concerning failure rates!Once again I have to point out that putting things into space is not like traveling along level ground where you can stop at any convenient point to rest. Going into space is quite literally taking a leap. You can't cross a canyon by taking two small jumps. or, to paraphrase Heinlien: "Once you are in LEO your are ONLY half way to anywhere." Halfway across a canyon doesn't do you much good!The economics of spaceflight have to take this into account. The only economical reason for space-based assembly and or staging is if--for whatever reason--you can't build a big enough launch vehicle to send your spacecraft to its destination in one go, or there is some resource ALREADY in orbit that you can get without having to lug it up from Earth in the first place. An example of this might be a space-based tether or perhaps supplies launched into orbit by some ultra-cheap method like laser launch or mass-driver that is unsuitable for larger more fragile cargo. This WILL come, but again this goes far beyond the scope of Project Constellation which can put everything it needs on its way to the moon with one small crew launch and one big cargo launch.
Jim - 30/11/2006 8:19 AMQuotewingod - 30/11/2006 2:00 AMAdd four "SRB's" for heavy payloads and for MARS. This makes the vehicle unsuitable for the LC-39 complex. none of the current infrastructure could be used.
wingod - 30/11/2006 10:45 AMQuoteJim - 30/11/2006 8:19 AMQuotewingod - 30/11/2006 2:00 AMAdd four "SRB's" for heavy payloads and for MARS. This makes the vehicle unsuitable for the LC-39 complex. none of the current infrastructure could be used.Hmmm... Not unsuitable for LC-39 C or D.A launch pad is going to cost more than what they are doing now?
Jim - 30/11/2006 9:53 AMQuotewingod - 30/11/2006 10:45 AMQuoteJim - 30/11/2006 8:19 AMQuotewingod - 30/11/2006 2:00 AMAdd four "SRB's" for heavy payloads and for MARS. This makes the vehicle unsuitable for the LC-39 complex. none of the current infrastructure could be used.Hmmm... Not unsuitable for LC-39 C or D.A launch pad is going to cost more than what they are doing now?I meant LC-39 complex area, VAB included. Nothing other than the SRB facilities would be applicableLC-39 C or D are just landmarks
Jim - 30/11/2006 12:50 PMI was referring to that there are no infrastructure out there to modify. It would be a new start. And could be called SLC-504 bays does not equate to 4 pads. Apollo used 3 bays (4th bay was never outfitted) and 1 pad (except for Apollo 10). It was 2-3 bays per pad. Pads C and D were associated with 6 and 8 bays VAB and nuke upperstages
Bill White - 30/11/2006 9:46 PMIf the destination is EML-1 or EML-2 then are all LEO inclinations are essentially equal? What about launch windows to EML-1 or EML-2 from various LEO inclinations?
Norm Hartnett - 1/12/2006 11:29 AMIf I might broaden the original question somewhat. What about the station and Mars and Beyond? Would utilizing the station for assembly of Mars craft impose prohibitive fuel overhead for TMI? Would using the station for lunar staging provide experience for Mars and Beyond?
RedSky - 1/12/2006 8:51 PMQuoteNorm Hartnett - 1/12/2006 11:29 AMIf I might broaden the original question somewhat. What about the station and Mars and Beyond? Would utilizing the station for assembly of Mars craft impose prohibitive fuel overhead for TMI? Would using the station for lunar staging provide experience for Mars and Beyond?Sad to say, but ISS will most likely be long gone by the time of any manned Mars voyage. Even if it is somehow extended by Russia and ESA after NASA leaves in 2016... I doubt it'll last till the 2030s... probably the earliest date for any Mars trip. Any potential new station, if built by the US (though unlikely) would probably be in a much more favorable orbital inclination, anyway. From the scale and nature of what a Mars vehicle would have to be... (Surface Habitat, living quarters, food and water stores, etc) it would almost be like assembling a small station in LEO by itself. Therefore, it would act as its own assembly base in LEO.
hmh33 - 2/12/2006 5:33 AMMore sun for the solar panels (a vehicle with 0 inclination in LEO must be in night for almost half of each orbit, a polar orbit in the right plane can provide continuous illumination)
josh_simonson - 3/12/2006 2:46 PMThe main limitation in spaceflight right now is the cost of spacecraft, not of the launch vehicles. A supply depot allows the use of re-useable spacecraft - which can reduce costs dramatically. As it is, the Aries V will be capable of orbiting around 800t per year of spacecraft, but NASA will only be able to afford to build about 250t of spacecraft, leaving a large amount of expensive spare capacity on the Aries V.
khallow - 3/12/2006 7:59 PMI'm not sure I disagree, but I think I do. Even if the vehicles aren't reusable, manufacturing multiple mostly identical vehicles will lower costs. Even when NASA makes two instead of one copy of a vehicle, they see substantial savings (eg, the marginal cost of building the second MER is stated as costing half as much as the first including development costs). Second, it doesn't make sense to launch an unreliable vehicle that costs $1000 per ton, if you will pay say $5000 per ton for launch costs. Currently, the ante for a space mission is huge. The remainder of the bet must be pretty good to justify it.
Jim - 3/12/2006 5:13 PMQuotekhallow - 3/12/2006 7:59 PMI'm not sure I disagree, but I think I do. Even if the vehicles aren't reusable, manufacturing multiple mostly identical vehicles will lower costs. Even when NASA makes two instead of one copy of a vehicle, they see substantial savings (eg, the marginal cost of building the second MER is stated as costing half as much as the first including development costs). Second, it doesn't make sense to launch an unreliable vehicle that costs $1000 per ton, if you will pay say $5000 per ton for launch costs. Currently, the ante for a space mission is huge. The remainder of the bet must be pretty good to justify it.Still have to launch the second vehicle and not on the launch vehicle
khallow - 3/12/2006 11:12 PMQuoteJim - 3/12/2006 5:13 PMQuotekhallow - 3/12/2006 7:59 PMI'm not sure I disagree, but I think I do. Even if the vehicles aren't reusable, manufacturing multiple mostly identical vehicles will lower costs. Even when NASA makes two instead of one copy of a vehicle, they see substantial savings (eg, the marginal cost of building the second MER is stated as costing half as much as the first including development costs). Second, it doesn't make sense to launch an unreliable vehicle that costs $1000 per ton, if you will pay say $5000 per ton for launch costs. Currently, the ante for a space mission is huge. The remainder of the bet must be pretty good to justify it.Still have to launch the second vehicle and not on the launch vehicleBy "vehicle" I meant cargo not a launch vehicle. Bad choice of words, I'll correct it.There's a bunch of numbers out there. I think the total mission for MER was just over $800 million through the end of the first year after landing on Mars including $100 million for launch costs and $75 million for mission control. The $600+ million remainder is the cost of the two probes. Only a third of that was the marginal cost of adding a second rover.The original poster was claiming, if I understand correctly, that NASA couldn't afford to make more than 250 tons of stuff. I don't know where that claim comes from. But I was pointing out an example that shows substantial decrease in cost for the second item.