SpaceX test-fires 'Raptor' rocket that will take humans to Mars

engadget ^ | 9/26/16 | Steve Dent

[ETL]

Actually, now that you reminded me, there is a slight amount of air at that altitude which does create a minor amount of drag, particularly when the atmosphere swells during moments of increased solar activity. In fact, they need to fire its on-board boosters in order to increase its altitude during these times. Otherwise it would be going too slow to remain in orbit at that particular altitude. However, at no point here is it ever "flying". Do you think it uses its solar panels as "wings"?

[ETL]

“This plot [see chart at link] shows the orbital height of the ISS over the last year. Clearly visible are the re-boosts which suddenly increase the height, and the gradual decay in between. The height is averaged over one orbit, and the gradual decrease is caused by atmospheric drag.

As can be seen from the plot, the rate of descent is not constant and this variation is caused by changes in the density of the tenuous outer atmosphere due mainly to solar activity.”

http://heavens-above.com/IssHeight.aspx?lat=40.7759&lng=-73.9677&loc=Unspecified&alt=21&tz=EST

[ETL]

[Wonder Warthog]

"It's a lot easier when you are only 250 miles from Earth."

It's not "distance from Earth" that matters, but "time on station". You use the latter to model and find solutions for the former.

[Wonder Warthog]

I can only say that you are seriously out of touch, both with solutions proposed and solutions tested. Pretty much every aspect you mention has been addressed conceptually, and often experimentally. Closed loop recycling has been under experimental development for almost fifty years, both on earth and in space, and would really only apply during the actual "on-planet" phase, and possibly not even then.

You appear to be under the misconception that this will be a "one ship trip".....it won't. Drone ships will be pre-launched and landed on Mars with materials and supplies, and possibly even during the transit phase (launched after the manned vehicle, but using higher accelerations to catch up and match velocity "in-flight").

Shielding is just a matter of arranging the mass you already have to carry, and will probably be water (actually ice). See "storm shelter" concept.

[aquila48]

Stay tuned... Musk is going to reveal some of his ideas tomorrow at a conference in Guadalajara.

http://www.theverge.com/2016/9/21/12891322/elon-musk-spacex-mars-colonization-mission-rocket

[chaosagent]

Drinking and eating what used to be urine and feces, without Earth’s gradual recycling through soil and sun that allows us to not have to think about it, is something the astronauts might have to learn to stomach.

---

Sorry, but the astronauts on the ISS are already ‘stomach’ing this. The ISS recycles 93% of its water, including urine.

[Clutch Martin]

I understand the curiosity and the “need” to discover, but my inference was purely logistical.

Right now, with our current technology, the only viable solution would have to be robotics.

Mars seems to be about the limit of endurance for human travel.

[Wonder Warthog]

"Right now, with our current technology, the only viable solution would have to be robotics."

"Right now, with our current technology..." the US couldn't put a man on the moon, yet we once did. Technology changes. Musk and others are driving those changes, since NASA has been emasculated and eviscerated.

"Mars seems to be about the limit of endurance for human travl."

Based on what?? The limit of endurance depends on the conditions of the system used, and neither you nor I know what that will be. All the technology discussed by Arthur C. Clarke in 2001 is realizable with today's technology base.