IdaX
Member
Naw, there wasn't a quick switch. Elon just forgot an apostrophe, saying "Mars orbit" instead of "Mars' Orbit".
-
Want to remove ads? Register an account and login to see fewer ads, and become a Supporting Member to remove almost all ads.
Falcon Heavy to Launch Next Month, Musk Says He's Sending His Roadster to Mars
- Thread starter anticitizen13.7
- Start date
A foam sabot wouldn't be a half-bad idea. Wrap the car in airtight plastic, suck the air out, build a two-part frame around it, cover the car and frame in spray foam (except around where the seam will be), let set, cut the plastic at the seam, pull apart the frame segments enough to make it detach from the car, and voila - you have a sabot. Spring-load them so that they'll fly apart and keep them bound together for launch with ties that are closed with a melt-away wire, to be melted at deployment.
Of course, you'd be launching a car *and* two pieces of debris into space
I wonder if there's any good foams that decompose in the vacuum of space, and would have enough structural strength to not need reinforcement... something that depolymerizes upon dessication. Surely there are some good options...Hmm, just thought of an issue. Until the roadster gets to near Mars, it's going to have some pretty heavy insolaton loads, with no convective cooling. I'd expect plastics to melt. The UV flux is going to destroy the epoxy binder in short order regardless. I wonder if they're planning to launch the roadster "bare and exposed to space", or if they'll wrap it in a protective bag so that it actually lasts a reasonable length of time? I mean, clearly the metal components won't be disappearing any time soon, but...
Sorry, but orbital mechanics disagree: Satellite on orbit around Mars at distance r from center of Mars has speed vr=dr/dt away or towards Mars (ignoring sideways speed). When r has max value (=r_max), vr = 0. Satellite approaching Mars cannot have vr=0 at r_max, because it is approaching Mars. So at every point incoming satellite will have more speed than orbiting satellite. This energy has to go somewhere or incoming satellite will not get to orbit around Mars.
Gravity sling around Mars will not change speed relative to Mars. Martian moons have too weak gravity. Roadster is not allowed to enter atmosphere. F9 would need active cooling system to prevent LOX from boiling away. So this is only possibility:
---
This is a cool idea. But I would rather send it to Moon with soft landing. Perhaps one day somebody would drive it. It is light load for FH even with battery. Perhaps second stage would have enough fuel. Pack Roadster into foam, so that it survives even if 2. stage does not stay upright.
This year Tesla probably achieves 0.1 % of Earths new car sales. If it keeps up 50% yearly growth, it will get to 98 % in 17 years. Car market grows, so 18 years to 100%. Company growing 50% yearly cannot make profit, so Musk could be on Mars before Tesla makes profit.
HankLloydRight
No Roads
Oh, so you can tell I've watched too much Mythbusters?
That's going to be some photo -- just the Roadster orbiting around Mars/Sun/Earth.
Last edited:
Oh, so you can tell I've watched too much Mythbusters?
That's going to be some photo -- just the Roadster orbiting around Mars/Sun/Earth.
If they do leave it unprotected, I.e. planning on it degrading quickly. I don't know which path they'll choose.
You know, one thing that I find kind of interesting.... so what happens when the epoxy binder in the CF degrades? There's almost no torque on the thing. Some trivial tidal forces as it passes by planets, but that's about it no? Would the CF fabric even come apart without its binder in space? I guess if there are some internal stresses.... I guess you'd also get some thermal stresses as the vehicle rotates, one side going into sun and the other shadow at periodic intervals. And minor centripetal force, too.
The glass shouldn't degrade. But thermal stresses will be high if the car is unprotected - it might not even need minor impact damage to weaken it enough to crack. Now, it's lamintated glass... but laminations are plastic (not even vacuum rated); eventually that'll degrade enough in the high UV flux that the glass debris cloud slowly floats away.
(Thinking about thermal stresses - maybe it might be smart to spin the vehicle up. Keep it rotating fast enough that no side is left in the sun for very long, so the temperatures average out. It'll also then keep a fixed orientation rather than tumbling.)
The debris aspect may sound bad, but we're talking a ***very*** large, very empty orbit (MTO). It'll take an unthinkably long amount of time for the debris to distribute its true anomaly (position in orbit), and even then it'd only be spread out along a single orbit in a ***very*** big range of potential transfer orbits.
I find it kind of funny to think about the tires (assuming they leave them on, deflated). Any small amount of air inside, or outgassing air, will reinflate them (assuming the valve stems are on) - to an extremely low pressure, but they should recover their usual shape, in theory at least. Of course, they're not rated for vacuum exposure, or the high UV/radiation flux of space. Like plastics, they probably won't last all that long.
I really hope NASA takes the opportunity to try to photograph the Roadster upon closest approach (for example, with MRO). I assume HiRISE can target objects in space? It'd be great for those "astronomy image of the day" pictures that are used to raise public interest.
Oh, one more thing: would be nice if Musk installed a couple corner-cube reflectors on the Roadster. Then you could do laser ranging to it, which might some day be useful for e.x. gravity or solar wind pressure studies.
Didn't have time to jump on this thread properly before but just to say:
- I always presumed that he meant it would be fired towards Mars orbit (around the Sun) rather than into orbit around Mars, because installing the hardware to circularise the orbit would be a serious faff.
- I was also concerned about degradation of the epoxy in the cf and the chassis bonding I didn't see discussed.
- There is no way they would launch anything without a finite element analysis to see how it would react to the vibration environment of the launcher.
- Roadsters rattle when they are driving down a rough bit of highway, I fear with 8 minutes of that sort of ride they might jettison the fairing and several body panels at the same time.
- If so, I doubt SpaceX would want anything to jeopardise what is a crucial demonstration flight. If I was Gwynne Shotwell I would not be allowing this unless a lot of analysis had been done and that would take a year.
- A Roadster is nowhere near heavy enough or "satellitey" to be a good facsimile for a typical payload this thing will carry. Most other flights of this type carry some sort of instrumented mass dummy.
So either they have been planning this for a long time and are super confident the thing will survive, or to me the risk doesn't really justify the reward.
Either way I recon Elon must have had one too many calls from his SC suggesting they change the PEM...
- I always presumed that he meant it would be fired towards Mars orbit (around the Sun) rather than into orbit around Mars, because installing the hardware to circularise the orbit would be a serious faff.
- I was also concerned about degradation of the epoxy in the cf and the chassis bonding I didn't see discussed.
- There is no way they would launch anything without a finite element analysis to see how it would react to the vibration environment of the launcher.
- Roadsters rattle when they are driving down a rough bit of highway, I fear with 8 minutes of that sort of ride they might jettison the fairing and several body panels at the same time.
- If so, I doubt SpaceX would want anything to jeopardise what is a crucial demonstration flight. If I was Gwynne Shotwell I would not be allowing this unless a lot of analysis had been done and that would take a year.
- A Roadster is nowhere near heavy enough or "satellitey" to be a good facsimile for a typical payload this thing will carry. Most other flights of this type carry some sort of instrumented mass dummy.
So either they have been planning this for a long time and are super confident the thing will survive, or to me the risk doesn't really justify the reward.
Either way I recon Elon must have had one too many calls from his SC suggesting they change the PEM...
HankLloydRight
No Roads
Like I said, expandable, degradable, foam sabot.
But I'm still skeptical this is a real thing. Great PR in either case, though.
No, not that epoxy, the good space grade version.
http://www.epotek.com/site/files/brochures/pdfs/low_outgassing_brochure.pdf
Epoxies and adhesives fit for space
Perhaps with an atomic oxygen resistant additive.
http://www.eas.uccs.edu/~tlilly/SPC...bit atomic oxygen on spacecraft materials.pdf
Mostly a joke. On the more reasonable side, maybe they made a Nuclear Glass fairing for the Roadster instead of (or inside of) a normal one...
Unfortunately, it's not simply about outgassing; epoxies suffer UV degradation (and radiation degradation for that matter), and there's a huge unshielded flux in space. On the other hand, while a huge nuclear glass fairing containing a Tesla Roadster as it drifts through space would be prohibitively expensive, it would also be totally awesome
Unfortunately, it's not simply about outgassing; epoxies suffer UV degradation (and radiation degradation for that matter), and there's a huge unshielded flux in space. On the other hand, while a huge nuclear glass fairing containing a Tesla Roadster as it drifts through space would be prohibitively expensive, it would also be totally awesome
Sounds like the sort of thing that would find it's way onto the Heart of Gold.
I dearly hope that they've got some sort of deployable camera that will be able to take photos of the Roadstar with Mars zipping by in the background.
BrokerDon
Active Member
I'm interesting in knowing the Falcon HEAVY launch date "window" too. Might be worth a road trip. I still remember my dad taking me to one of the Apollo launches when I was a kid. AbSoFreakinLutely AMAZING !!!
Fred Thompson
Member
Similar threads
