Elon Musk will likely reveal more details about the Interplanetary Transport system on the one year anniversary of the first announcement at the 2016 International Astronautical conference. IAC2017, hosted by the Space Industry Association of Australia (SIAA) will take place in Adelaide, Australia from 25 29 September 2017.
Robert Zubrin, Longtime Mars Colonization advocate, gave a Critique of the SpaceX Interplanetary Transport System.Zubrin was struck by many good and powerful ideas in the Musk plan. However, Musks plan assembled some of those good ideas in an extremely suboptimal way, making the proposed system impractical. Still, with some corrections, a system using the core concepts Musk laid out could be made attractive not just as an imaginative concept for the colonization of Mars, but as a means of meeting the nearer-at-hand challenge of enabling human expeditions to the planet.
http://www.prometheism.net/elon-will-likely-reveal-more-details-on-his-big-mars-colonization-rocket-at-iac-2017-sept-25-29-2017-next-big-future/
Old, but consistent with rethinking the v0.1 design from IAC 2016.Many here believed single step to 4x Saturn V was not feasible (or wise).
2) "Too many engines, look what happened to N-1". This is not a very good argument, as the steering system of BRF is different than ITS, BFR cannot fail because roll control engine fails because there are no dedicated roll control engines, and BRF has much better redundancy as N-1.
Quote from: AncientU on 05/29/2017 10:50 amhttp://www.prometheism.net/elon-will-likely-reveal-more-details-on-his-big-mars-colonization-rocket-at-iac-2017-sept-25-29-2017-next-big-future/Original article is from nextbigfuture (not the most reputable news source on the Internet...): http://www.nextbigfuture.com/2017/05/elon-will-likely-reveal-more-details-on-his-big-mars-colonization-rocket-at-iac-2017-sept-25-29-2017.htmlZubrin's critics was from last year, pretty old.
Quote from: AncientU on 05/29/2017 11:32 amOld, but consistent with rethinking the v0.1 design from IAC 2016.Many here believed single step to 4x Saturn V was not feasible (or wise).About the criticism of the "too big BFR/ITS":I've heard mostly arguments:1) "LC-39 is not build for such thrust and completely new launch site is needed."This seems to be a valid argument, though not a showstopper.2) "Too many engines, look what happened to N-1". This is not a very good argument, as the steering system of BRF is different than ITS, BFR cannot fail because roll control engine fails because there are no dedicated roll control engines, and BRF has much better redundancy as N-1.
I really hope that this information can be trickled out in advance this time rather than a big dump all at once.It would be nice to see some more properly prepared questions from the audience. I don't think all the secrecy followed by splashy presentations is doing well to get official buy in on the ITS.
What will EM present this year?
Robert Zubrin, Longtime Mars Colonization advocate, gave a Critique of the SpaceX Interplanetary Transport System....Many new spins on original IAC design by RZ.
The fast transit times enables a round-trip each synod per EM....Whatever the final size of the early vehicles, on-orbit refueling and fast transfers will (hopefully) remain.
A short squat 12m booster with 16 engines and a reusable second stage/spacecraft ...
Quote from: AncientU on 05/29/2017 10:50 amWhat will EM present this year?I think the original ITS presentation was a very compelling display of how, with modest technology improvements to chemical rockets, affordable transportation between Earth and an established Mars space port becomes plausible.
It did not show a roadmap of how such a space port could be built, which is likely what put-off critics like Zubrin. Hopefully that will be the focus of the next ITS talk.A more plausible scale-up would use a 12 m diameter landing capsule, which could be sent to Mars by a single launch of a 200-300 ton-to-LEO rocket. Trans-Mars mass would be around 60-90 t (to stay in the 0.8t/m^2 range that is talked about), and the surface payload about half that. This would align with Zubrin's suggestion that the initial trans-Mars habitat should stay on Mars as crew housing. This also allows stockpiling supplies on Mars prior to crew arrival, to make the Mars base the "second safest place in the solar system" (to quote an old Zubrin statement). A crew capsule also allows implementation of a launch escape system.
With a capsule-based architecture, the first stage could be the full scale (or somewhat shorter & lighter, but full 12m width) reusable ITS booster (e.g. 34 Raptor engines). Making an interim expendable second stage would reduce the development cost to get the first capsules launched. A sea barge landing of the booster reduces the size and cost of the expendable second stage (e.g. 4 Raptor engines). When available, the reusable tanker second stage could also carry the landing capsule, but it would require 2 launches and an LEO re-fueling (or 1 launch and an expendable 3rd stage).
With the upcoming debut of the Falcon Heavy, there is also a chance that SpaceX will start with a smaller 3-core ITS variant, to allow a set of 9.5 m diameter cores to loft the same 300 tons-LEO (90-100t to Mars). This suggestion would make Zubrin happier, but a 9.5 m dia upper-stage ship is not as well suited to landing 300 tons on Mars (tall & skinny is less desirable for broadside entry and vertical landing). So maybe the 3-core variant has to fly an expendable 2nd stage (and capsules for 1-way transport) until the 12m re-usable 2nd stage is ready. A 12 m capsule might get built in a small factory, but a 12m 2nd stage needs a factory large enough to build a full 12 m booster. So why spend the money building a factory/infrastructure for 9.5 m boosters?I think the initial ITS will be 12 m diameter, reusable booster, expendable 2nd stage, capsule lander (perhaps with derated Raptor thrust and stack mass, for 160-250t LEO); that path has a good balance of "not too far beyond Falcon" and "leads to the full ITS", and reduces the amount of "starting over" between steps. The expendable 2nd stage also provides the versatility for more SLS missions.