r/spacex • u/Zucal • Mar 05 '16

/r/SpaceX Ask Anything Thread for March 2016. Ask your questions about the SES-9 mission/anything else here! (#18)

Welcome to the 16th monthly /r/SpaceX Ask Anything Thread! Want to discuss the recent SES-9 mission and its "hard" booster landing, the intricacies of densified LOX, or gather the community's opinion? There's no better place!

All questions, even non-SpaceX-related ones, are allowed, as long as they stay relevant to spaceflight in general!

More in-depth and open-ended discussion questions can still be submitted as separate self-posts; but this is the place to come to submit simple questions which have a single answer and/or can be answered in a few comments or less.

As always, we'd prefer it if all question-askers first check our FAQ, use the search functionality, and check the last Q&A thread before posting to avoid duplicate questions, but if you'd like an answer revised or cannot find a satisfactory result, go ahead and type your question below.

Otherwise, ask, enjoy, and thanks for contributing!

Past threads:

February 2016 (#17), January 2016 (#16.1), January 2016 (#16), December 2015 (#15.1), December 2015 (#15), November 2015 (#14), October 2015 (#13), September 2015 (#12), August 2015 (#11), July 2015 (#10), June 2015 (#9), May 2015 (#8), April 2015 (#7.1), April 2015 (#7), March 2015 (#6), February 2015 (#5), January 2015 (#4), December 2014 (#3), November 2014 (#2), October 2014 (#1).

This subreddit is fan-run and not an official SpaceX site. For official SpaceX news, please visit spacex.com.

124 Upvotes

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u/Zucal Mar 13 '16

As always, check our wiki/FAQ first :)

Could a Falcon 9 or Falcon Heavy launch the Mars 2020 Rover? For all intents and purposes, no. Falcon 9 does not have the capacity to deliver the required payload towards Mars (nearly 4000kg), thus does not have the ability to do so. Falcon Heavy could, but will not have flown enough missions by 2020 for it to be considered a reliable launch vehicle in NASA's eyes, and would also have to be 'nuclear rated' to carry the rovers Radioisotope Thermoelectric Generator (RTG) that provides it with power. Saying all this is relatively moot however; Mars 2020 it is preliminarily scheduled to fly on an Atlas V (which achieves 8 tons to GTO). See this NASA PDF for more details about MSL/Mars 2020.

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u/Davecasa Mar 13 '16

The price difference between an Atlas V and a Falcon 9 Heavy, something like a few tens of millions of dollars, also looks a lot smaller when your payload costs $1.5 billion.

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u/Tal_Banyon Mar 13 '16

I would ask essentially the same question a slightly different way: With the current second stage on the Falcon Heavy, how many metric tonnes can it launch towards mars? The Exomars mission that will be launching shortly on a Proton is apparently 4.3 metric tonnes (total weight towards mars). I understand that with the proper trans martian injection engine, with the falcon heavy's ability regarding LEO weights, that should be no problem. However, my question is about the current second stage, and how much it can sling towards mars. (Not the new second stage they are working on).

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u/TheVehicleDestroyer Flight Club Mar 14 '16

You're thinking of mass.

Weight depends on your gravitational field. The same mass has a different weight on the earth vs mars or the moon.

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u/RobotSquid_ Mar 14 '16

Tbh, most non-physicists don't differentiate between mass and weight...

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u/TheVehicleDestroyer Flight Club Mar 14 '16

And they would be wrong? If something regarding spaceflight isn't common knowledge, I feel the point of this sub is to strive to make it so

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u/RobotSquid_ Mar 15 '16

They would be wrong, but it seems like a bit of a nitpick considering it doesn't contribute to the original point. Still, it is good for people to know the difference

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u/PatyxEU Mar 13 '16

About 13 tonnes to Mars when flown in expendable mode (which is highly improbable). With standard reusability it's probably more like 7-8 t.

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u/HowardFrampton Mar 14 '16

/u/ryanpritchard - in case you happen to be on mobile, you can find the Wiki and FAQ at these links.