Warning: what follows are random musings, extrapolating ISS current crew and cargo vehicles to LOP-G. Let's suppose that ISS operations stops in 2024. What will happen to the varied cargo / crew vehicles developed since COTS, in 2006 ? {snip}
BFR I dont think has any chance of flying by 2024 and even if it was...1) there is no hint as to what its actual cost will be "per seat" and
One can also wonder about Japan HTV. Once again, H2 can't lift it to DRO. Maybe this will encourage Japan to build a more powerful variant of the H3 that could reach DRO carrying an upgraded HTV ?
Quote from: TripleSeven on 07/30/2018 09:29 amBFR I dont think has any chance of flying by 2024 and even if it was...1) there is no hint as to what its actual cost will be "per seat" and'Less than a long distance economy ticket'. (of the order of $1000/pax, $1m per flight)Admittedly, this is long term.If BFS can hit its cost goal of $5M/flight, and be certified to fly people, it can make lots of money.$15M per flight, with 100 people equals around $150K/ticket.A third of that goes into incremental costs, a third into paying off the airframe, and a third is profit.At around 30-60 flights, you're in profit.Add an initial ten flights during qualification that launch re-purposed cryogenic tanks outfitted for comfort, and you can do a week in a small hotel room with windows on the earth, with almost no development. (said tanks are $2m or so for 400m^3, leak negligible heat either way even in atmosphere, have double skins, both quite capable of supporting pressure loads with a large margin.)
where do you find this faith. I am all ears. Faith to me is the evidence of things hoped for the evidenceof things unseen...You are going to a 5M flight ...when well has Elon flown anyone?I dont think you and Elon are going to change technological history
Quote from: MATTBLAK on 07/22/2018 01:39 pmOrion/SLS (Block 1B) is supposed to have a 'surplus', co-manifested payload ability of about 10 metric tons. Perhaps the Orion could bring a tanker module with it each time to refuel a reusable Lander? Just an idea...Hmmm..... The Apollo LM's total propellant load (ascent and descent stages together) was about 11 tonnes. An Apollo-style lander today could no doubt get away with less propellant by saving weight and burning, say, lox/methane or maybe even lox/hydrogen rather than NTO/Aerozine 50. But the dry weight of the LM's ascent stage was less than a quarter that of the descent stage. If you want a reusable lander, you're going to have to haul something roughly equivalent to the descent stage all the way from the surface back to the staging point, and that means burning a lot more propellant. That propellant itself needs to be landed on the moon in the first place, so we're talking about a much larger vehicle.Then there's the fact that, delta-V-wise, LOP-G is about 700 m/s further (one way) from the lunar surface than was the Apollo LM when it began its descent from LLO.So I don't think Orion/SLS's 10-tonne co-manifested payload capability helps much for fueling a crewed lander.
Orion/SLS (Block 1B) is supposed to have a 'surplus', co-manifested payload ability of about 10 metric tons. Perhaps the Orion could bring a tanker module with it each time to refuel a reusable Lander? Just an idea...
Quote from: Proponent on 07/22/2018 03:10 pmQuote from: MATTBLAK on 07/22/2018 01:39 pmOrion/SLS (Block 1B) is supposed to have a 'surplus', co-manifested payload ability of about 10 metric tons. Perhaps the Orion could bring a tanker module with it each time to refuel a reusable Lander? Just an idea...Hmmm..... The Apollo LM's total propellant load (ascent and descent stages together) was about 11 tonnes. An Apollo-style lander today could no doubt get away with less propellant by saving weight and burning, say, lox/methane or maybe even lox/hydrogen rather than NTO/Aerozine 50. But the dry weight of the LM's ascent stage was less than a quarter that of the descent stage. If you want a reusable lander, you're going to have to haul something roughly equivalent to the descent stage all the way from the surface back to the staging point, and that means burning a lot more propellant. That propellant itself needs to be landed on the moon in the first place, so we're talking about a much larger vehicle.Then there's the fact that, delta-V-wise, LOP-G is about 700 m/s further (one way) from the lunar surface than was the Apollo LM when it began its descent from LLO.So I don't think Orion/SLS's 10-tonne co-manifested payload capability helps much for fueling a crewed lander.It's around 5,000 m/s from EML-1 to the surface and back. That means storables need a mass ratio of about 5, methalox about 4, and hydrolox about 3.So a hydrolox lander would have 10 t of prop, about 1 t of tanks, and 4 t for all other dry mass (assuming everything that goes down also goes up). Since the whole LEM, including both stages, was only ~4300 kg dry, that seems entirely feasible.A methalox lander would be 10 t of prop, 0.5 t of tanks, and 2.8 t for everything else. The LEM ascent stage was ~2150 kg dry, so that would be tight but perhaps possible.A storable lander would be 10 t of prop, 0.5 t of tanks, and 2 t for everything else. That's cutting it mighty close, but might be possible with balloon tank construction.
Quote from: envy887 on 07/30/2018 05:43 pmQuote from: Proponent on 07/22/2018 03:10 pmQuote from: MATTBLAK on 07/22/2018 01:39 pmOrion/SLS (Block 1B) is supposed to have a 'surplus', co-manifested payload ability of about 10 metric tons. Perhaps the Orion could bring a tanker module with it each time to refuel a reusable Lander? Just an idea...Hmmm..... The Apollo LM's total propellant load (ascent and descent stages together) was about 11 tonnes. An Apollo-style lander today could no doubt get away with less propellant by saving weight and burning, say, lox/methane or maybe even lox/hydrogen rather than NTO/Aerozine 50. But the dry weight of the LM's ascent stage was less than a quarter that of the descent stage. If you want a reusable lander, you're going to have to haul something roughly equivalent to the descent stage all the way from the surface back to the staging point, and that means burning a lot more propellant. That propellant itself needs to be landed on the moon in the first place, so we're talking about a much larger vehicle.Then there's the fact that, delta-V-wise, LOP-G is about 700 m/s further (one way) from the lunar surface than was the Apollo LM when it began its descent from LLO.So I don't think Orion/SLS's 10-tonne co-manifested payload capability helps much for fueling a crewed lander.It's around 5,000 m/s from EML-1 to the surface and back. That means storables need a mass ratio of about 5, methalox about 4, and hydrolox about 3.So a hydrolox lander would have 10 t of prop, about 1 t of tanks, and 4 t for all other dry mass (assuming everything that goes down also goes up). Since the whole LEM, including both stages, was only ~4300 kg dry, that seems entirely feasible.A methalox lander would be 10 t of prop, 0.5 t of tanks, and 2.8 t for everything else. The LEM ascent stage was ~2150 kg dry, so that would be tight but perhaps possible.A storable lander would be 10 t of prop, 0.5 t of tanks, and 2 t for everything else. That's cutting it mighty close, but might be possible with balloon tank construction.Dang. So much for such a large and powerful rocket as SLS. Is Orion SO heavy that it let only 10 mt to a lander ? Oh boy...
And even if you want to do refueling in a lunar orbit it would be better to do that away from any habitats for safety reasons.
Thing is, at the time, crewed capsules to date had tended to be in the 6-10 mt range
Apollo CM: 5.8 MtX-38 CRV: 8.2 MtSoyuz TMA: 7.2 MtShenzhou: 7.8 MtDragon: 8 MtDreamchaser: 9 MtCST-100: 13 Mt