Author Topic: Falcon Heavy Demo Mission Payload Discussion  (Read 134596 times)

Offline LewisS

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #300 on: 12/04/2017 02:35 PM »
I wonder if Elon is a AAA member. If he is then he should call them up and ask for a tow after the mission.

Online speedevil

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #301 on: 12/04/2017 04:47 PM »
Sending a car to Mars is a stunt.  Tracking, monitoring and commanding it when it gets there is not.

In principle, it may be possible to negotiate a few bytes from MAVEN or similar, for basic presence comms, as it passes Mars.

A 2m class dish, and uplink system would in principle be quite within the mass budget, get a megabit or three a second if they can buy DSN time, or rather less without, but would mean developing new hardware that has little near-term use, and may be too constrained for later mars use.

Though they might view this as worth it.

Reusing existing hardware is also an option.
Starlink has several 15cm optical dishes, presumably for LASER comms.

Several meter class telescopes at various points on the ground are relatively inexpensive, and combined with a several watt LASER the 15cm dish will illuminate about a 1Mm spot on earth at mars furthest distance.
A 1m dish would pick up 10^-12 of this, or around 3*10^-12W, for a 6W laser 50% modulated, or 10^7 photons/s.
Visible magnitude around 10, about the same as Phobos at close approach.
Phobos is easily visible in amateur scopes of under 50cm. (in good seeing, with good geometry).

I think it's safe to assume a datarate of several tens of kilobits a second downlink near Mars, without heroic optical efforts, even in the absence of extraordinary effort, for a cost of tens of thousands of dollars in ground equipment, rather than millions.

The pointing of the mirror does of course need good 3-axis stabilisation of the craft. But starlink satellites are likely to want good pointing on their mirrors for signal strength reasons if nothing else.

The starlink satellite will need moderately larger solar panels and various things to cope better with the environments on mars, but given that Elon has explicitly stated he plans to put starlink or similar around Mars, it does not seem a huge stretch to imagine that this might be available at least in a prototype form.

Imagine also if it just so happens that the mirrors on the standard starlink can be flipped into a low bitrate mode and do kilobits to Mars with a six inch mirror on the far end, megabits to the moon, or a kilobit to Jupiter.

(much higher with a larger mirror, and clearly not if you cross the planet or get too close as it's too bright).







Offline Senex

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #302 on: 12/04/2017 04:52 PM »
Can you imagine the final odometer reading on the Tesla... :o ;D

There would never be one . . .     ;)
« Last Edit: 12/04/2017 09:09 PM by Senex »

Offline envy887

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #303 on: 12/04/2017 04:55 PM »
If you wanted to enthuse govt HSF, you'd lob a boilerplate Dragon capsule on a cislunar trajectory.

I think Jim has shot down this idea many times...


No, Jim has shot down the idea of lobbing a functional Dragon to cislunar space. A boilerplate capsule doesn't have to be powered, networked or air conditioned while in the fairing, or have a functional payload adapter. It's also not nearly as interesting because it really wouldn't test any of Dragon's cislunar capabilities.

Offline Formica

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #304 on: 12/04/2017 04:57 PM »
What do you mean by this? I would be gobsmacked if they didn't recover the center core. While it is basically a one off prototype, it will provide a virtual gold mine of engineering data for future block 5 gen center cores. From my admittedly amateur perspective, it seems downright foolish to expend it. (I may also be misinterpreting your statement.)

When asked about it, Elon Musk said he thinks they can land the central core on a Red Dragon mission to Mars. Thats borderline but a  very demanding mission.

True. That said, the Roadster is a much lower mass payload than Red Dragon was to be. It's outside the optimum transfer window, so that could contribute to a hotter landing profile as well, but still, 1500kg vs 10,000kg is a huge difference. Granted, we still don't know if the Roadster will have some kind of spacecraft bus on it, but so far, the answer appears to be "probably not" since we know they aren't doing MOI. Ergo, recovering the center core seems doable, and again, extremely valuable from an engineering perspective.
I'm just a space fan, please correct me if I'm wrong!

Offline DistantTemple

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #305 on: 12/04/2017 05:25 PM »

Maybe he wanted his own, better variant of it. "I can do better things with my car than those eccentric British fellows that launched their on a rocket".
Teslas go more than 54 miles, or even 54 million miles before running out of juice. Top Gear is the fake, and history is showing real men and women can make world changing rocket engines in their garages, rather than motorised sheds. Tesla doesn't need to take the mick out of the lovely Reliant Robin, or mess around with exploding stage props, as they are the cutting edge of space, car and battery technology, applying adult intellect, and not thrills for 8 year old "men".
We can always grow new new dendrites. Reach out and make connections and your world will burst with new insights. Then repose in consciousness.

Offline laszlo

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #306 on: 12/04/2017 05:42 PM »
I do wonder if Elon has offered to his employees to place a personal item maybe limited in size and weight in the trunk. I would send a sample of hair (dna) or maybe a bit of my moms ashes Or maybe a DVD with family photos and videos.
Fish food for the inhabitants of the Atlantic's newest reef ;) <running for his life dodging brickbats...>

Online dror

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #307 on: 12/04/2017 05:47 PM »


Considering how much a sci-fi nerd Elon is, I suppose he (perfectly) knows about this peculiar Top Gear episode.

Maybe he wanted his own, better variant of it. "I can do better things with my car than those eccentric British fellows that launched their on a rocket".

Plus a Tesla roadster is far more sexier than a Reliant Robin - it is kind of comparing Margaret Thatcher with Taylor Swift.

Oh, Musk has bigger issues with top gear than that. He could be doing it just to spite


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Offline nacnud

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #308 on: 12/04/2017 05:59 PM »
Can you imagine the final odometer reading on the Tesla... :o ;D

There wouldn't be one . . .     ;)

I have images of Ferris Bueller's day off running through my head

Offline jpo234

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #309 on: 12/04/2017 06:31 PM »
Some naysayer see a man launching a car to Mars, I see a man giving his old Roadster a proper viking funeral...

So, are you saying it is going to be on fire?.  I think that is a wrong analogy.
Fire is going to carry it to Valhalla.
You want to be inspired by things. You want to wake up in the morning and think the future is going to be great. That's what being a spacefaring civilization is all about. It's about believing in the future and believing the future will be better than the past. And I can't think of anything more exciting than being out there among the stars.

Offline sanman

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #310 on: 12/04/2017 06:33 PM »
Can you imagine the final odometer reading on the Tesla... :o ;D

There wouldn't be one . . .     ;)

I have images of Ferris Bueller's day off running through my head


Offline jpo234

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #311 on: 12/04/2017 06:44 PM »
Have not seen this one yet:
You want to be inspired by things. You want to wake up in the morning and think the future is going to be great. That's what being a spacefaring civilization is all about. It's about believing in the future and believing the future will be better than the past. And I can't think of anything more exciting than being out there among the stars.

Offline cppetrie

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #312 on: 12/04/2017 06:55 PM »
Have not seen this one yet:

This was posted on Saturday and says itís launching in 6 months...uh...January is not 6 months away. 6 weeks maybe.

Offline jpo234

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #313 on: 12/04/2017 07:04 PM »


Have not seen this one yet:

This was posted on Saturday and says itís launching in 6 months...uh...January is not 6 months away. 6 weeks maybe.

It's a running gag that the first FH launch is and always will be 6 months away.
You want to be inspired by things. You want to wake up in the morning and think the future is going to be great. That's what being a spacefaring civilization is all about. It's about believing in the future and believing the future will be better than the past. And I can't think of anything more exciting than being out there among the stars.

Offline john smith 19

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #314 on: 12/04/2017 07:23 PM »

Reusing existing hardware is also an option.
Starlink has several 15cm optical dishes, presumably for LASER comms.

Several meter class telescopes at various points on the ground are relatively inexpensive, and combined with a several watt LASER the 15cm dish will illuminate about a 1Mm spot on earth at mars furthest distance.
A 1m dish would pick up 10^-12 of this, or around 3*10^-12W, for a 6W laser 50% modulated, or 10^7 photons/s.
Visible magnitude around 10, about the same as Phobos at close approach.
Phobos is easily visible in amateur scopes of under 50cm. (in good seeing, with good geometry).

I think it's safe to assume a datarate of several tens of kilobits a second downlink near Mars, without heroic optical efforts, even in the absence of extraordinary effort, for a cost of tens of thousands of dollars in ground equipment, rather than millions.

The pointing of the mirror does of course need good 3-axis stabilisation of the craft. But starlink satellites are likely to want good pointing on their mirrors for signal strength reasons if nothing else.

The starlink satellite will need moderately larger solar panels and various things to cope better with the environments on mars, but given that Elon has explicitly stated he plans to put starlink or similar around Mars, it does not seem a huge stretch to imagine that this might be available at least in a prototype form.

Imagine also if it just so happens that the mirrors on the standard starlink can be flipped into a low bitrate mode and do kilobits to Mars with a six inch mirror on the far end, megabits to the moon, or a kilobit to Jupiter.

(much higher with a larger mirror, and clearly not if you cross the planet or get too close as it's too bright).
Exactly. 

The actual payload is not really the point, or even that important (although pictures of Mars from the parking cams should be interesting).

The skills needed to implement the goal (and of course proving FH works as a system) are the goal. Most of that will not be on obvious display.

And all of them tie into the goal of going to Mars.  Hitting a target that's 5000x further away than any payload SX has launched so far.
BFS. The worlds first Methane fueled FFORSC engined CFRP structured A380 sized aerospaceplane tail sitter capable of flying in Earth and Mars atmospheres. BFR. The worlds biggest Methane fueled FFORSC engined CFRP structured booster for BFS. First flight to Mars by end of 2022. Forward looking statements. T&C apply. Believe no one. Run your own numbers. So, you are going to Mars to start a better life? Picture it in your mind. Now say what it is out loud.

Offline envy887

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #315 on: 12/04/2017 07:42 PM »

Reusing existing hardware is also an option.
Starlink has several 15cm optical dishes, presumably for LASER comms.

Several meter class telescopes at various points on the ground are relatively inexpensive, and combined with a several watt LASER the 15cm dish will illuminate about a 1Mm spot on earth at mars furthest distance.
A 1m dish would pick up 10^-12 of this, or around 3*10^-12W, for a 6W laser 50% modulated, or 10^7 photons/s.
Visible magnitude around 10, about the same as Phobos at close approach.
Phobos is easily visible in amateur scopes of under 50cm. (in good seeing, with good geometry).

I think it's safe to assume a datarate of several tens of kilobits a second downlink near Mars, without heroic optical efforts, even in the absence of extraordinary effort, for a cost of tens of thousands of dollars in ground equipment, rather than millions.

The pointing of the mirror does of course need good 3-axis stabilisation of the craft. But starlink satellites are likely to want good pointing on their mirrors for signal strength reasons if nothing else.

The starlink satellite will need moderately larger solar panels and various things to cope better with the environments on mars, but given that Elon has explicitly stated he plans to put starlink or similar around Mars, it does not seem a huge stretch to imagine that this might be available at least in a prototype form.

Imagine also if it just so happens that the mirrors on the standard starlink can be flipped into a low bitrate mode and do kilobits to Mars with a six inch mirror on the far end, megabits to the moon, or a kilobit to Jupiter.

(much higher with a larger mirror, and clearly not if you cross the planet or get too close as it's too bright).
Exactly. 

The actual payload is not really the point, or even that important (although pictures of Mars from the parking cams should be interesting).

The skills needed to implement the goal (and of course proving FH works as a system) are the goal. Most of that will not be on obvious display.

And all of them tie into the goal of going to Mars.  Hitting a target that's 5000x further away than any payload SX has launched so far.

They won't be tangibly "hitting a target". Mars isn't going to be there when the Roadster gets to the other end of the Hohmann transfer.

But they can still calculate the accuracy of the orbital insertion as long as the upper stage is alive and can be tracked from Earth. That will tell them if the payload would have hit Mars if it launched in an interplanetary window.

Offline Hotblack Desiato

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #316 on: 12/04/2017 08:04 PM »
The idea of putting a Tesla Roadster in a martian orbit reminds me of this nice episode:



http://memory-alpha.wikia.com/wiki/Ford_truck

It's just in the wrong quadrant...

Offline Rocket Science

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #317 on: 12/04/2017 08:08 PM »


Considering how much a sci-fi nerd Elon is, I suppose he (perfectly) knows about this peculiar Top Gear episode.

Maybe he wanted his own, better variant of it. "I can do better things with my car than those eccentric British fellows that launched their on a rocket".

Plus a Tesla roadster is far more sexier than a Reliant Robin - it is kind of comparing Margaret Thatcher with Taylor Swift.
And it won't roll over as often... ;D
"The laws of physics are unforgiving"
~Rob: Physics instructor, Aviator, Vintage auto racer

Online speedevil

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #318 on: 12/04/2017 08:29 PM »
They won't be tangibly "hitting a target". Mars isn't going to be there when the Roadster gets to the other end of the Hohmann transfer.

But they can still calculate the accuracy of the orbital insertion as long as the upper stage is alive and can be tracked from Earth. That will tell them if the payload would have hit Mars if it launched in an interplanetary window.

There are in principle >2y trajectories for the first week or so of January, to Mars, without greatly boosting the delta-v needed.

It rapidly climbs to the levels at which the Jan 18 window for a Jupiter-> Saturn (6.5km/s) mission becomes cheaper, with the option of a few hundred m/s trajectory to Uranus.
Alas, outer planet missions that actually do something are completely implausible right now cheaply anyway.

« Last Edit: 12/04/2017 08:41 PM by speedevil »

Offline john smith 19

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Re: Falcon Heavy Demo Mission Payload Discussion
« Reply #319 on: 12/04/2017 10:40 PM »
As long as he has enough thrust/duration for boosters/US, he could be off by as much as 30 degrees in any direction and make a heliocentric orbit. So sans LOM or severe under performance, no big deal.
Actually an attractive feature, given the range is about 5000x larger than SX have ever operated at before.

Everything above that is a bonus.  A fairly classic SX operating tactic.
Quote from: Space Ghost 1962
You've identified your biggest serious competitor has a very long successful launch record and a strong pre-existing relationship with several large institutional customers. You simply can't match this because you have just not been in the business long enough to do so.
Sounds ... fatalistic?
I should probably have qualified that SX has not been in the business long enough yet.
SX can do so if they keep up a high enough launch rate for long enough (and without any more failures).
Quote from: Space Ghost 1962
Quote
Fortunately for you they are effectively handicapped by joint parents who are completely fixated on short term gains and don't believe there is anything to worry about.

Which suits you just fine.

So you need to test you new LV without obviously demonstrating the level of skills you have in a way that's obvious enough to arouse the concern of your competitors parents.
So the advantage gained is to not "scare the competition"?
Technically it's not scaring the BoD of the parents.  They control the purse strings. I think Bruno is already taking SX quite seriously.
Quote from: Space Ghost 1962
Quote
On this basis any fairly heavy object would be suitable as a surrogate payload.
Sending your car to Mars maintains the "Elon Musk, what a crazzzzy guy, eh?" image, while in fact giving your Operations team a fairly hard test of their skills in trajectory design and propulsion management, while fulfilling the goal that anything SX does is with aim of getting you to Mars betters/faster/cheaper.
Advantage of "crazzzy guy" please?
Possibly a  poor choice of words? How about "bold" or "flamboyant"?

You seem to be treating this as just a test launch of a new SX LV. Something of interest to potential SX customers only.

But SX (and Musk) have always spoken to several audiences. If your end game is to establish a settlement of a million people on Mars the spade work for raising public awareness of that has to start sooner rather than later.
 
Quote from: Space Ghost 1962
Sounds to me all we're saying here is coming up with ways to "handicap" (as in golf) the performance, in asking for a "mulligan" in advance?
You were aware that one of his earlier comments was along the lines of "There's a fair chance it will explode.  My only hope is it will clear the pad before it does so" ?

While many commentards have always been optimistic on SX's chances of success (at anything) Musk himself has always been very careful to manage expectations, possibly following the 3 in a row failures of F1's before ultimate success.

So no he's doing what he's done with (AFAIK) all F9 flights and showing caution. Don't confuse his comments with other people's. 

But if FH did fail what would SX do?

Simple.

Figure out what went wrong and launch another.
I think that's a key point of SX. 

They regret launch failure, they do not fear it.


BFS. The worlds first Methane fueled FFORSC engined CFRP structured A380 sized aerospaceplane tail sitter capable of flying in Earth and Mars atmospheres. BFR. The worlds biggest Methane fueled FFORSC engined CFRP structured booster for BFS. First flight to Mars by end of 2022. Forward looking statements. T&C apply. Believe no one. Run your own numbers. So, you are going to Mars to start a better life? Picture it in your mind. Now say what it is out loud.

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