Give it up already. No HSF craft ever had a "mini me", no one ever will.
Quote from: Space Ghost 1962 on 02/19/2017 04:45 amGive it up already. No HSF craft ever had a "mini me", no one ever will. There have been scaled prototypes such as the DC-X and X-33 for proof of concept.
A prototype might be a good idea instead of dropping billions into the largest rocket ever made. Probably won't happen because Musk is impatient. He wants to go to Mars and doesn't want to waste time, ending up too old to go.
I wish SpaceX success and hope ITS works as planned, but there is a chance this design won't work. Remember Lockheed was confident about the X-33 and it failed before having a test flight.
Smaller versions that initially fly to Mars, I see no way of that happening. Too expensive and too time consuming.
If the smaller vehicle has a development path to something smaller serving the satellite launch market that is fine. Quite possible, but that would be something else than a subscale precursor entirely. It would likely happen parallel, probably later than ITS.
Maybe just a Falcon with two liquid propellant side boosters. How long could that take?
How about a merlin-based booster (ITS-lite) with 42 Merlins on the bottom?
My recollection is he said it afterwards I think in the 2nd Q+A from Reddit. He definitely said it, also that the 2nd landing with crew would complete the propellant plant.
We are still far from figuring this out in detail, but the current plan is:Send Dragon scouting missions, initially just to make sure we know how to land without adding a crater and then to figure out the best way to get water for the CH4/O2 Sabatier Reaction.Heart of Gold spaceship flies to Mars loaded only with equipment to build the propellant plant.First crewed mission with equipment to build rudimentary base and complete the propellant plant.Try to double the number of flights with each Earth-Mars orbital rendezvous, which is every 26 months, until the city can grow by itself.
Looking over the ITS plans and comparing them to either Mars Direct or SLS...it's on the verge of insanely ambitious. ... Would it be easier to build a smaller version of ITS first beforehand or not? Say something either at 1/2 or 2/3 scaled compared to the full ITS.
Quote from: redliox on 02/16/2017 11:03 pmLooking over the ITS plans and comparing them to either Mars Direct or SLS...it's on the verge of insanely ambitious. ... Would it be easier to build a smaller version of ITS first beforehand or not? Say something either at 1/2 or 2/3 scaled compared to the full ITS.I think they could retire a lot of risk with something much smaller. But for several reasons, I think a dual core Falcon 9, maturing to a 4 core, would be required to get enough lift to address the goal that I see as doable without huge investment.That goal is a single full sized Raptor powered reusable carbon composite second stage with some sort of reusable fairing system. Was it Elon Musk or Gwynne Shotwell that said that they want to reuse but don't want to have them land in the water? That means an air capture or maybe something more wild like small wings and engine to try and fly them back. In any case it will add weight. The dual core could support an elliptical cross section second stage supporting an elliptical cross section fairing of something like 8 x 5.5 meters. I could imagine a three section fairing where the two large sections would separate and return as they are planning now, with a small third section staying with the stage and payload. This section would act as the leading edge upon re-entry. This idea would not require huge heavy new payloads, just something like a lunar lander or maybe Europa mission class payload to justify development. I think lunar development with 1 lunar mission every 26 months in support of 1 SLS launch and 1 Mars mission at that launch window might be enough for NASA to consider contributing to development cost. If this reusable technology can be demonstrated at this scale, THEN I could see going on to a full scale ITS. It will need tremendous ground support development as has been noted before. Though I still don't see a Mars colony developing for at least 50 - 75 years.
Quote from: DigitalMan on 02/19/2017 02:09 pmMy recollection is he said it afterwards I think in the 2nd Q+A from Reddit. He definitely said it, also that the 2nd landing with crew would complete the propellant plant.I think this is what you're referring to?https://www.reddit.com/r/spacex/comments/590wi9/i_am_elon_musk_ask_me_anything_about_becoming_a/QuoteWe are still far from figuring this out in detail, but the current plan is:Send Dragon scouting missions, initially just to make sure we know how to land without adding a crater and then to figure out the best way to get water for the CH4/O2 Sabatier Reaction.Heart of Gold spaceship flies to Mars loaded only with equipment to build the propellant plant.First crewed mission with equipment to build rudimentary base and complete the propellant plant.Try to double the number of flights with each Earth-Mars orbital rendezvous, which is every 26 months, until the city can grow by itself.Emphasis mine. Nothing about the crew living in ITS. I guess you can read that into it during "base construction time", but it's clear he doesn't want people living in them any longer than needed.Also... IMHO.... not too comforting that he doesn't plan to have the propellant plant even finished, let alone have propellant stocks onhand, when the first colonists arrive. They better well hope that nothing goes wrong that requires an evacuation (not an unlikely event), or all of them will be dead.
Quote from: gin455res on 02/19/2017 07:25 pmHow about a merlin-based booster (ITS-lite) with 42 Merlins on the bottom?What risk would you be trying to retire with this? Would you build it with composite tanks? What role would it play in the 2020's?
Why would you launch a reuseable spacecraft/entry vehicle in a fairing? It has to take aero loads on return anyway.
And there is absolutely no reason to develop a multi-core Falcon anything other than Heavy. If you can't do it on Heavy it's not worth doing.
Quote from: redliox on 02/18/2017 04:51 amSomeone double-check my figures to be certain; however I think for a smaller mission this could suffice to get the ship to Mars even without the tanker Elon wants in the full version.Not suggesting there is anything wrong with your ΔV calculations, but when you talk about a scale model, that refers to a linear dimension, not to mass. What you are describing is roughly a 0.8 scale model of the ITS.
Someone double-check my figures to be certain; however I think for a smaller mission this could suffice to get the ship to Mars even without the tanker Elon wants in the full version.
Quote from: OneSpeed on 02/18/2017 10:59 amQuote from: redliox on 02/18/2017 04:51 amSomeone double-check my figures to be certain; however I think for a smaller mission this could suffice to get the ship to Mars even without the tanker Elon wants in the full version.Not suggesting there is anything wrong with your ΔV calculations, but when you talk about a scale model, that refers to a linear dimension, not to mass. What you are describing is roughly a 0.8 scale model of the ITS.Elaborate on scale models. I'm curious is there's an optimal scale that is best for testing, not to mention whether it's better to scale by volume or by mass.
Elaborate on scale models. I'm curious is there's an optimal scale that is best for testing, not to mention whether it's better to scale by volume or by mass.
Quote from: redliox on 02/21/2017 02:31 amElaborate on scale models. I'm curious is there's an optimal scale that is best for testing, not to mention whether it's better to scale by volume or by mass.The engineering choice to model a design is not bound by any single optimal scale. There are many reasons to use, and not to use scale models.SpaceX has produced scale models of some of their designs as proofs of concept. Falcon 1 was roughly 1/3 the scale of Falcon 9, but they never produced the 1/2 scale Falcon 5 version, and history shows it wasn't necessary for them to test at that scale.
When I was a kid watching Apollo 11, and 2001: A Space Odyssey, if you asked me back then that in 50 years would Musk's ITS was too large, I would have expected that kind of scale. But I also expected that there would have been moon bases with commercial flights flying there, and man would be on Mars before the end of the 20th century. So back then, looking 50 years ahead, this would make perfect sense. Somehow, we lost the future that looked so promising back then. What ITS does is give us back the future.HOWEVERThe scale is ludicrous, and there is no business case for it. I understand Musk's rational, to have the economics to go to Mars for less than a quarter million dollars per passenger. But let's put our business hats on. He should build a 1/4 scale lander, focus on orbital space tourism, lunar tourism and even a true space shuttle for space deliveries. The rocket is too large for just about any commercial or government client. Maintain a cash flow while perfecting the technology and let the systems mature. Sure, there will be duplicate costs by building two systems instead of one, but a two pronged approach won't bankrupt him. It reminds me of Howard Hughes' Spruce Goose. Build it and he can only afford one flight with it.