I think RobW was talking about the tanker.
The ITS as described at IAC 2016 is awesome. The only two things I think you could reasonably object to are the raw size (impracticality large thrust for LC39a and Brownsville), the ambitious landing tech, and maybe the lack of abort....But the basic idea behind ITS just kicks most architectures' butts so hard that I don't think people have yet realized how much better this approach is. Just two stages, with a couple variants of the upper stage, is all the vehicle you need.
Why can't the entire ITS serve as an escape system? It's certainly got a lot of engines at the back to escape a failing booster?
Quote from: stcks on 05/29/2017 11:36 pmQuote from: envy887 on 05/29/2017 11:31 pmI don't expect development of long term on orbit main tank cryo storage because it's not critical to ITS.It is though, for varying definitions of long term. ITS will need to be refueled over a handful of tanker flights which could take a bit of timeNot if you can live with the boil-off losses during the fueling campaign. The trade-off is between developing long-term, main tank cryo management, and launching a bit more fuel during the refueling campaign. If the fuel needed for the Mars ship is not an exact multiple of the tanker capacity, you already have some 'free' excess fuel that can go toward making up for the boil-off.
Quote from: envy887 on 05/29/2017 11:31 pmI don't expect development of long term on orbit main tank cryo storage because it's not critical to ITS.It is though, for varying definitions of long term. ITS will need to be refueled over a handful of tanker flights which could take a bit of time
I don't expect development of long term on orbit main tank cryo storage because it's not critical to ITS.
How feasible would active cooling be, using the 200kw of solar power available on the ITS?
Not if you can live with the boil-off losses during the fueling campaign. The trade-off is between developing long-term, main tank cryo management, and launching a bit more fuel during the refueling campaign.
Quote from: Kaputnik on 05/30/2017 11:09 amHow feasible would active cooling be, using the 200kw of solar power available on the ITS?What is this "active cooling" using power? Any power you use needs to be radiated off, too, otherwise it's rather heating than cooling.
Quote from: pippin on 05/30/2017 12:14 pmQuote from: Kaputnik on 05/30/2017 11:09 amHow feasible would active cooling be, using the 200kw of solar power available on the ITS?What is this "active cooling" using power? Any power you use needs to be radiated off, too, otherwise it's rather heating than cooling.Refrigeration. Of course the process generates extra heat has to be radiated away.
Well, yes, possible, but veeeery inefficient
Yea, if you've got a square kilometer of radiation surface or it's small volume or you're willing to shed a lot of gas in exchange. All as I said above.