Musk to Mars

[Pipcard]

I don't know why you have to assume a 29-tonne all-CH4 or RP-1 rocket or 25-tonne LH2 upper stage rocket, 23 tonnes is the expendable capacity of F9 FT.

I admit, you're making some decent points here about the disadvantages of multiple payload slots. And it does sound ridiculous for an SLS-sized launcher to be launching 1-tonne payloads, even if it is fully reusable. But I guess some people would prefer launching their small payloads as secondaries on a reusable Falcon 9, while others might require a dedicated smallsat launcher from another provider for their particular orbital needs. One is not completely better than the other.

7 hours ago, fredinno said:

Interesting.

(If you want, you could get a NASAspaceflight account and continue the debate there and not just with me, but just remember that the mods are a little more strict over there and probably won't tolerate stuff like snarky image macros as much)

Quote

And yet you said: "it might use space refueling", so it could just do that to send 100T to Mars.

Granted, even a 210T to LEO vehicle (ie Saturn C-8) was capable of launching at LC-39A.

And we can even go up to 362T to LEO, which supposedly used the same facilities as Saturn. No idea if that exended to pads.

http://www.astronautix.com/lvs/satv4260.htm

I think we can safely say it's probably not using refueling for at least the first 3 decades of its existence if it seriously needs a new pad.

An SLS Block II-sized monolithic reusable rocket would lift 130 tonnes in expendable mode, and possibly a 30% payload penalty in RTLS reuse mode. 90 tonnes to low Earth orbit. Maybe it might have over 100 tonnes if the first stage landed on a barge, but that's cutting it close.

I'm guessing they just want a pad all to themselves for their giant rocket, without schedule interference from anyone else. Not because it's too big for LC-39. It also still needs refueling to beat the rocket equation.

Edited June 13, 2016 by Pipcard

[fredinno]

12 hours ago, Pipcard said:

I don't know why you have to assume a 29-tonne all-CH4 or RP-1 rocket or 25-tonne LH2 upper stage rocket, 23 tonnes is the expendable capacity of F9 FT.

I admit, you're making some decent points here about the disadvantages of multiple payload slots. And it does sound ridiculous for an SLS-sized launcher to be launching 1-tonne payloads, even if it is fully reusable. But I guess some people would prefer launching their small payloads as secondaries on a reusable Falcon 9, while others might require a dedicated smallsat launcher from another provider for their particular orbital needs. One is not completely better than the other.

(If you want, you could get a NASAspaceflight account and continue the debate there and not just with me, but just remember that the mods are a little more strict over there and probably won't tolerate stuff like snarky image macros as much)

An SLS Block II-sized monolithic reusable rocket would lift 130 tonnes in expendable mode, and possibly a 30% payload penalty in RTLS reuse mode. 90 tonnes to low Earth orbit. Maybe it might have over 100 tonnes if the first stage landed on a barge, but that's cutting it close.

I'm guessing they just want a pad all to themselves for their giant rocket, without schedule interference from anyone else. Not because it's too big for LC-39. It also still needs refueling to beat the rocket equation.

Yeah? Except GTO satellites always get bigger, so you need some payload margin.

https://en.m.wikipedia.org/wiki/Proton_(rocket_family)

Proton is a similar low isp rocket (but uses 4-5 stages), so I used it as a rough estimate of what we need for a non-H2 rocket (though not a very fair comparison).

Also, Ariane 5 is 10T to GTO (enough for the GTO market), and 21 T to LEO (the DOD upgraded Delta IV Heavy to 25T to LEO, so we can assu me we need at least 25T to LEO if we want to capture every payload...

Again, this is oriented to future market demands, which still predicts bigger sat for the time being.

 http://spaceflight101.com/spacerockets/ariane-5-eca/

https://en.wikipedia.org/wiki/Delta_IV_Heavy

When you make a "catch all" reusable rocket, you need to design for the largest possible payload, like the Shuttle did- and that is around the 25-29T to LEO range. I would choose the latter rather than the former for payload margin reasons.

 

 

Edited June 13, 2016 by fredinno

[fredinno]

15 hours ago, Pipcard said:

 

I admit, you're making some decent points here about the disadvantages of multiple payload slots. And it does sound ridiculous for an SLS-sized launcher to be launching 1-tonne payloads, even if it is fully reusable. But I guess some people would prefer launching their small payloads as secondaries on a reusable Falcon 9, while others might require a dedicated smallsat launcher from another provider for their particular orbital needs. One is not completely better than the other.

Granted, so far F9 is cheaper than any smallsat operator, but that's largely because no one has come about to actually do a SpaceX style cost reduction there (why did the F1 have to be retired, why. It just had to wait a few years for it to shine again... )

And one is not better than the other, necessarily. However, generally, satellite operators would rather choose one at a time (unless they are building a constellation of sats) than end up having to do inclination change maneuvers and decreasing satellite lifetime a few years just because that was slightly cheaper to launch on. Many smallsats lack good engines anyways, meaning that it would be very difficult to capture the smallsat market on a single 29T to LEO rocket.

Making one big rocket would actually reduce demand for a rocket compared to a modular system. SpaceX mainly couldn't be bothered to care about smallsat markets right now when they have the higher $$$ GTO market to capture from ArianeSpace.

15 hours ago, Pipcard said:

21 hours ago, fredinno said:

 

(If you want, you could get a NASAspaceflight account and continue the debate there and not just with me, but just remember that the mods are a little more strict over there and probably won't tolerate stuff like snarky image macros as much)

I can't imagine mods being even more strict than they are on here. I got slammed for saying the f-word, even though I censored myself. Really?

15 hours ago, Pipcard said:

An SLS Block II-sized monolithic reusable rocket would lift 130 tonnes in expendable mode, and possibly a 30% payload penalty in RTLS reuse mode. 90 tonnes to low Earth orbit. Maybe it might have over 100 tonnes if the first stage landed on a barge, but that's cutting it close.

I'm guessing they just want a pad all to themselves for their giant rocket, without schedule interference from anyone else. Not because it's too big for LC-39. It also still needs refueling to beat the rocket equation.

As I said earlier, with 60s tech, rockets up to at least 210 T expendable were proposed for LC-39A/B.

With modern engines, tankage, and tech, I would image

And I can't imagine they'd be much interference, or at least any more than they already get from the Cape. SLS can only launch 3x per year, max.

LC-39B will be empty most of the year, 9 months out of 12 months if we make the pessimistic assumption NASA decides to hog LC-39 for a month every time SLS launches.

Plus, NASA still has empty land right above LC-39B that was supposed to host LC-39C, and still remains empty (because no one has ever needed that extra megapad). It would probably be cheaper than building a new pad if they needed they extra launch capability, since the land was drained in the 60s, and there's already plentiful experience launching the world's biggest rockets from that location. They would have to start back to the very start of that process at Brownsville. Maybe they eventually plan to move all F9 Cape pads there to save rent costs. Don't think the cost would ever be recuperated, but SpaceX isn't my company.

 

One thing I am concerned about BFR are the engines.

http://www.astronautix.com/engines/f1.htm

https://en.wikipedia.org/wiki/Raptor_(rocket_engine)

They're too small, even for a monolithic SLS Block II sized rocket.

https://en.wikipedia.org/wiki/Raptor_(rocket_engine)

http://www.astronautix.com/engines/f1.htm

To match the trust of the Saturn V, you would need 17 engines total on a single core. The last time that configuration was conjured up... well.

Yeah. That might  be a problem....

Thankfully, we have almost 50 years of experience with rockets since then, and realistically, a 130T BFR would need less engines due to higher efficiency, but... still. I fear for the BFR. If it blows up (especially with humans), SpaceX's Mars Dreams go along with it.

 

Regardless, I did some calculations:

http://www.silverbirdastronautics.com/LVperform.html

Using the Raptor on the 1st stage (27x!- talk about N-1 parallels), and a H2 staged combustion 2nd stage (4x SSME-Vac on the 2nd stage)SSME-Vac on the 3rd stage) (I know what you're going to say, but this is strictly about maximizing payload- and it's probably not going to fly too much anyways, at first, and thus, they have plenty of time to iron out the difficulties with making reusable H2 stage combustion much cheaper (and have a huge amount of SSME work to build on). It's definitely not impossible, since NASA engineers have tried their hand on it plenty of times. It's just more difficult). Adding a nozzle extension promotes ISP by ~40s.

SpaceX also uses propellant densification on all stages, and coupled with SpaceX's amazing ability to increase mass fractions to very high levels,

a 2 stage rocket with Raptor and SSMEs would resemble N-1 (we should call it the N-2 :P)- but it would have amazing payload- 380208 kg, or 380T to LEO!

And that's keeping within the thrust and mass/size limitations of LC-39A (defined by the Saturn C-8)!

We can assume the "3rd stage" is part of the payload. A 3-stage configuration sent to LEO (minus payload) could probably get well into 450T to LEO- the Saturn V with 2 stages held up 116T to LEO, while it held up to 140T to LEO under a 3 stage config.

https://en.wikipedia.org/wiki/Saturn_V

http://www.astronautix.com/lvs/satint21.htm

SpaceX could use LC-39A for BFR if they wanted to. They don't. Why is the real question.

 

Edited June 13, 2016 by fredinno

[PB666]

Quote

Thankfully, we have almost 50 years of experience with rockets since then, and realistically, a 130T BFR would need less engines due to higher efficiency, but... still. I fear for the BFR. If it blows up (especially with humans), SpaceX's Mars Dreams go along with it.

I think that fortunately for SpaceX/Musk they have put alot more thought into these things than you (or me). Armchair rocket scientist fears and pictures of soviet era rockets are no predictor of future success. I think that one thing they have that you don't have, that would be data, experience (much from test firings). I can't tell you what is a better strategy, RP-1 of lH2 but I can tell you that there performance is close enough together, it if was cost effective they could produce large cores, and anyone who doubts Musk can pull it off would be fooled. So that primarily your fears are not the issue, I'm sure they are looking at costs, if they can send 9 things into space link them up cheaper, or do they need to launch everything at once.

This effort is going to be made on the margin, unless NASA or some other GO decides to ante up, so its going to be about cost, if they fail, they will have to wait 2 years to retry on the cost margin. And I think Musk is looking at something else you are not looking, to be the supplier of interplanetary stocks and payload, so from that perspective he could write of cost/failures as cost of services sold. So just maybe over the next 2 years he will be investigating the market in that direction to see if there is interest. I see ESA, politically he would have to crack a barrier, NASA nothing yet but it could change, possible ISRU. If NASA ante's up then at least they could have contractual control of who else might get a ride, but that potential would be non-existent if the boca-chica site opens up.

So to answer your question, what much more important is whether they can keep on schedule and potentially expand launch in the next to year to get the required margin.

 

[fredinno]

3 hours ago, PB666 said:

I think that fortunately for SpaceX/Musk they have put alot more thought into these things than you (or me). Armchair rocket scientist fears and pictures of soviet era rockets are no predictor of future success. I think that one thing they have that you don't have, that would be data, experience (much from test firings). I can't tell you what is a better strategy, RP-1 of lH2 but I can tell you that there performance is close enough together, it if was cost effective they could produce large cores, and anyone who doubts Musk can pull it off would be fooled. So that primarily your fears are not the issue, I'm sure they are looking at costs, if they can send 9 things into space link them up cheaper, or do they need to launch everything at once.

This effort is going to be made on the margin, unless NASA or some other GO decides to ante up, so its going to be about cost, if they fail, they will have to wait 2 years to retry on the cost margin. And I think Musk is looking at something else you are not looking, to be the supplier of interplanetary stocks and payload, so from that perspective he could write of cost/failures as cost of services sold. So just maybe over the next 2 years he will be investigating the market in that direction to see if there is interest. I see ESA, politically he would have to crack a barrier, NASA nothing yet but it could change, possible ISRU. If NASA ante's up then at least they could have contractual control of who else might get a ride, but that potential would be non-existent if the boca-chica site opens up.

So to answer your question, what much more important is whether they can keep on schedule and potentially expand launch in the next to year to get the required margin.

 

Quote

And I think Musk is looking at something else you are not looking, to be the supplier of interplanetary stocks and payload, so from that perspective he could write of cost/failures as cost of services sold.

....wut?

Really?

It's debateable whether Elon will even get to Mars, let alone make a colony there.

Also, doing exactly what you suggest (writing off failures as costs) has been empirically proved to be a horrible idea. ie Aquarius, ie Proton after its recent failures.

No one wants to send a payload 2x (average, assuming F9) the cost of the rocket, only for it to go kaboom.

Quote

. I see ESA, politically he would have to crack a barrier, NASA nothing yet but it could change, possible ISRU.

Unless you're talking about Mars Missions here, that's unlikely.

3 hours ago, PB666 said:

 

So to answer your question, what much more important is whether they can keep on schedule and potentially expand launch in the next to year to get the required margin.

There will be no expansion if SpaceX constantly screws up it's launches, even screwing up 10% of the time is enough for satellite operators to run off in horror to ArianeSpace or ULA.

In fact, there will be a contraction. Doing what you propose is what doomed the Proton in recent years in the commerical market, even though it was cheap.

[PB666]

59 minutes ago, fredinno said:

....wut?

Really?

It's debateable whether Elon will even get to Mars, let alone make a colony there.

Also, doing exactly what you suggest (writing off failures as costs) has been empirically proved to be a horrible idea. ie Aquarius, ie Proton after its recent failures.

No one wants to send a payload 2x (average, assuming F9) the cost of the rocket, only for it to go kaboom.

Unless you're talking about Mars Missions here, that's unlikely.

There will be no expansion if SpaceX constantly screws up it's launches, even screwing up 10% of the time is enough for satellite operators to run off in horror to ArianeSpace or ULA.

In fact, there will be a contraction. Doing what you propose is what doomed the Proton in recent years in the commerical market, even though it was cheap.

The big payload companies know there will be failures, NASA had their fair share, and the competition in the last two years has not been doing that well.

Not talking about a Mars Mission but an interplanetary capability that starts with some sort of Mars delivery, it could be as simple as an S-M L1(L2) communication satellite delivery.

Your statement about running away in horror does not jibe, payload launching is not flying a Concorde, the only time people really freak out is when you screw up manned flights. I have seen so many failed launches that its just a accepted thing. For private space i'm somewhat amused when they don't fail.

And why are you predicting SpaceX will constantly screw up their launches? Is this another one of those 'The UN is bad' statements you are inclined to make.

 

[fredinno]

6 hours ago, PB666 said:

The big payload companies know there will be failures, NASA had their fair share, and the competition in the last two years has not been doing that well.

Not talking about a Mars Mission but an interplanetary capability that starts with some sort of Mars delivery, it could be as simple as an S-M L1(L2) communication satellite delivery.

Your statement about running away in horror does not jibe, payload launching is not flying a Concorde, the only time people really freak out is when you screw up manned flights. I have seen so many failed launches that its just a accepted thing. For private space i'm somewhat amused when they don't fail.

And why are you predicting SpaceX will constantly screw up their launches? Is this another one of those 'The UN is bad' statements you are inclined to make.

 

Quote

The big payload companies know there will be failures, NASA had their fair share, and the competition in the last two years has not been doing that well.

No excuse to cut costs on testing. I would argue the opposite, since that would attract satellite operators from those other companies.

Seriously, would you buy a 99% reliability rating for a Car (over a period of a year, just because it's cheaper (and the other one percent of the time, the car goes boom?)

Now explain why a satellite operator would accept a lower than 90% launch rating. IN many cases, it would actually increase net costs to choose the cheap but unreliable, due to insurance costs.

Quote

And why are you predicting SpaceX will constantly screw up their launches? Is this another one of those 'The UN is bad' statements you are inclined to make.

SO MUCH LOST IN TRANSLATION HOLY FREAKING COW!

I said IF they lower reliability ratings as you proposed- or I think you did. You need to improve on your writing, I usually can't fully understand it....
 

6 hours ago, PB666 said:

 

Your statement about running away in horror does not jibe, payload launching is not flying a Concorde, the only time people really freak out is when you screw up manned flights. I have seen so many failed launches that its just a accepted thing. For private space i'm somewhat amused when they don't fail.

That was hyperbole. I can tell you aren't the best in detecting it.

And large GEO Satellites generally cost in the ~$1Billion range. (which is also SpaceX's primary market). Anger them, and now it's mainly only NASA paying you.

You can see why satellite operators would rather choose reliable over cost saving. Which is likely why ULA gets any commercial launches at all.

6 hours ago, PB666 said:

 

Not talking about a Mars Mission but an interplanetary capability that starts with some sort of Mars delivery, it could be as simple as an S-M L1(L2) communication satellite delivery.

List 1 (one) comsat that has ever been sent to SE-L1, or ANY L point.

One.

I dare you.

No such market exists.

The closest thing to what you would be talking about is a ION/NTR (unlikely) reusable space tug from LEO to GEO, with the needed thrust to get to Mars. Probably not economical to use the space tug versions as Mars tugs, (without modifications, that is).

But even then, that's only a small portion of a Mars mission. You still need a HLV, unless you're planning only a few, Mars-Direct esque missions (which Elon does not seem to want to do- after all, he wants to colonize Mars.)

 

[PB666]

49 minutes ago, fredinno said:

No excuse to cut costs on testing. I would argue the opposite, since that would attract satellite operators from those other companies.

Seriously, would you buy a 99% reliability rating for a Car (over a period of a year, just because it's cheaper (and the other one percent of the time, the car goes boom?)

Now explain why a satellite operator would accept a lower than 90% launch rating. IN many cases, it would actually increase net costs to choose the cheap but unreliable, due to insurance costs.

SO MUCH LOST IN TRANSLATION HOLY FREAKING COW!

I said IF they lower reliability ratings as you proposed- or I think you did. You need to improve on your writing, I usually can't fully understand it....
 

That was hyperbole. I can tell you aren't the best in detecting it.

And large GEO Satellites generally cost in the ~$1Billion range. (which is also SpaceX's primary market). Anger them, and now it's mainly only NASA paying you.

You can see why satellite operators would rather choose reliable over cost saving. Which is likely why ULA gets any commercial launches at all.

List 1 (one) comsat that has ever been sent to SE-L1, or ANY L point.

One.

I dare you.

No such market exists.

The closest thing to what you would be talking about is a ION/NTR (unlikely) reusable space tug from LEO to GEO, with the needed thrust to get to Mars. Probably not economical to use the space tug versions as Mars tugs, (without modifications, that is).

But even then, that's only a small portion of a Mars mission. You still need a HLV, unless you're planning only a few, Mars-Direct esque missions (which Elon does not seem to want to do- after all, he wants to colonize Mars.)

 

You are a funny little kook, why do you need one for earth? Its more of a benefit for rovers and equipment on other planets, and if its been done before why does it need to be done? Isn't that the point he wants to deliver earth like delivery capabilities except around or near mars. Defense contractors have a long history in the U.S. at creating markets that don't exist, you think procurement contracts are a one way street, remind you of the Mark-14 torpedo.

[fredinno]

19 hours ago, PB666 said:

You are a funny little kook, why do you need one for earth? Its more of a benefit for rovers and equipment on other planets, and if its been done before why does it need to be done? Isn't that the point he wants to deliver earth like delivery capabilities except around or near mars. Defense contractors have a long history in the U.S. at creating markets that don't exist, you think procurement contracts are a one way street, remind you of the Mark-14 torpedo.

Holy cow, how is any of that relavent to this discussion?

[Kerbart]

21 hours ago, fredinno said:

Seriously, would you buy a 99% reliability rating for a Car (over a period of a year, just because it's cheaper (and the other one percent of the time, the car goes boom?)

Now explain why a satellite operator would accept a lower than 90% launch rating. IN many cases, it would actually increase net costs to choose the cheap but unreliable, due to insurance costs.

Because these decisions are made by boring middle-aged balding men with glasses, aka "accountants" (although the rest of the world calls them "bean counters") who will trust the output of their HP-10C's by a couple of magnitudes over their "gut feelings."

If the odds are good, you will roll the dice on a chance of failure. This is why SpaceX exists in the first place. ULA has the 100% success rate and the accompanying price tag. Now, if you're launching that once-in-a-lifetime science mission where you cannot afford to miss it, it's worth paying 10× what SpaceX charges. But if you're launching 4 comsats per year at $200M each then I'd rather pay $50 for a launch with 90% success than $500 for a launch with 100% success. Seriously, all that SpaceX needs to do is to establish a succesrate that is "good enough" for the price they charge.

With the above numbers, admittedly pulled out of where the sun don't shine:

4 launches @ $700M each = 2800;
6 launches @ $250M each = 1500 (assuming 2 extra launches due to failures)

Insurance cost isn't always a consideration, simply because not insuring is also an option which, if the premium gets high enough, is very attractive (the example above assumes no insurance premium).

[fredinno]

11 minutes ago, Kerbart said:

Because these decisions are made by boring middle-aged balding men with glasses, aka "accountants" (although the rest of the world calls them "bean counters") who will trust the output of their HP-10C's by a couple of magnitudes over their "gut feelings."

If the odds are good, you will roll the dice on a chance of failure. This is why SpaceX exists in the first place. ULA has the 100% success rate and the accompanying price tag. Now, if you're launching that once-in-a-lifetime science mission where you cannot afford to miss it, it's worth paying 10× what SpaceX charges. But if you're launching 4 comsats per year at $200M each then I'd rather pay $50 for a launch with 90% success than $500 for a launch with 100% success. Seriously, all that SpaceX needs to do is to establish a succesrate that is "good enough" for the price they charge.

With the above numbers, admittedly pulled out of where the sun don't shine:

4 launches @ $700M each = 2800;
6 launches @ $250M each = 1500 (assuming 2 extra launches due to failures)

Insurance cost isn't always a consideration, simply because not insuring is also an option which, if the premium gets high enough, is very attractive (the example above assumes no insurance premium).

INdeed, and SpaceX's "good enough relibability" price turns out to be higher than 95%. It seems that lower rates don't tend to be too favorable for satellite operators.

[PB666]

1 hour ago, fredinno said:

Holy cow, how is any of that relavent to this discussion?

None of my cows are religious. actually. 

32 minutes ago, fredinno said:

INdeed, and SpaceX's "good enough relibability" price turns out to be higher than 95%. It seems that lower rates don't tend to be too favorable for satellite operators.

Well they got up 2 today in one launch. Maybe next time they'll do 4 at a time. 

The only real problem with the last launch, we didn't get to see it blow up on the barge. 

[LordFerret]

On 6/14/2016 at 5:20 PM, PB666 said:

Is this another one of those 'The UN is bad' statements you are inclined to make.

That's actually me who makes those statements. Get your political protestors straight already. lol

I watched the launch. I also caught the news reported of the landing attempt, (as one news outlet put it): " rocket landing suffers 'unscheduled disassembly' ". Very Kerbal. Maybe that's the point? I still fail to see the usefulness of trying to land a rocket under power on a barge; The extra cost and weight of fuel, the technology involved. If you can reenter a vehicle with pinpoint accuracy as such, why not pop out chutes and landing legs and set the thing down in the space center's parking lot???

[CptRichardson]

26 minutes ago, LordFerret said:

That's actually me who makes those statements. Get your political protestors straight already. lol

I watched the launch. I also caught the news reported of the landing attempt, (as one news outlet put it): " rocket landing suffers 'unscheduled disassembly' ". Very Kerbal. Maybe that's the point? I still fail to see the usefulness of trying to land a rocket under power on a barge; The extra cost and weight of fuel, the technology involved. If you can reenter a vehicle with pinpoint accuracy as such, why not pop out chutes and landing legs and set the thing down in the space center's parking lot???

Because they CAN'T. To make a GTO flight plan, they cannot return to the pad.  It is actually vastly cheaper and easier and provides more payload capacity to go for the barge downrange and in the path the stage is inclined to go than it is to double up and RTB. And once more, chutes are vastly more expensive and less reliable than propulsive landing, and make it much harder to easily reuse their vehicles by adding a costly new step.

[Nibb31]

51 minutes ago, LordFerret said:

I still fail to see the usefulness of trying to land a rocket under power on a barge; The extra cost and weight of fuel, the technology involved. If you can reenter a vehicle with pinpoint accuracy as such, why not pop out chutes and landing legs and set the thing down in the space center's parking lot???

Seriously? After all the explaining that we've done?

When the first stage separates from the upper stage, it is 300km from the space center's parking lot, which happens to be above the ocean, travelling at Mach 6 above the atmosphere. To get back to the parking lot requires a boostback burn to get the rocket travelling in the opposite direction, back to the launch site. This requires a surplus in propellant, which the Falcon 9 doesn't have for GTO missions. It has enough fuel to decelerate and land, but not to boost back to the launch site.

As for the extra propellant for landing, parachutes are actually heavier. Parachutes could not land you precisely enough to aim for the space center's parking lot, especially if you are descending slow enough to not damage the rocket. Parachutes (especially large custom-built ones) are expensive to make, to check, and to pack. And most importantly, parachutes will not slow you down to 0m/s and 0m altitude. They will land your fragile rocket at a constant velocity, around 20m/s, which is going to break it unless you add even more weight for airbags, retro-rockets or super strong legs, all of which are more complex and heavier than the small amount of extra propellant needed for a soft landing.

 

Edited June 16, 2016 by Nibb31

[PB666]

8 hours ago, LordFerret said:

That's actually me who makes those statements. Get your political protestors straight already. lol

Well we expect it out of you, you want to be a rusty nail just for rust's sake. You kind of like to think of yourself as a Neanderthal. 

8 hours ago, LordFerret said:

I watched the launch. I also caught the news reported of the landing attempt, (as one news outlet put it): " rocket landing suffers 'unscheduled disassembly' ". Very Kerbal. Maybe that's the point? I still fail to see the usefulness of trying to land a rocket under power on a barge; The extra cost and weight of fuel, the technology involved. If you can reenter a vehicle with pinpoint accuracy as such, why not pop out chutes and landing legs and set the thing down in the space center's parking lot???

See responses above. However along a different set of lines......

How much did the specialized barge with 4 rather expensive pilot boat engines cost them?

How much does it cost to bring the rocket back, those enigines are horribly ineffecient for open seas travel and the design of the barges is worse still, should the contract out a pickup and transfer ship that will carry the rocket back to port. 

[CptRichardson]

1 hour ago, PB666 said:

Well we expect it out of you, you want to be a rusty nail just for rust's sake. You kind of like to think of yourself as a Neanderthal. 

See responses above. However along a different set of lines......

How much did the specialized barge with 4 rather expensive pilot boat engines cost them?

How much does it cost to bring the rocket back, those enigines are horribly ineffecient for open seas travel and the design of the barges is worse still, should the contract out a pickup and transfer ship that will carry the rocket back to port. 

A F9 is about $60 million at the moment.  Saving three so far by itself? Whatever it cost them, it's already made that back.

[PB666]

3 minutes ago, CptRichardson said:

A F9 is about $60 million at the moment.  Saving three so far by itself? Whatever it cost them, it's already made that back.

Only 1 as far as I know is going back into production. But we can't say what that is until some cost estimate is given.

[CptRichardson]

6 minutes ago, PB666 said:

Only 1 as far as I know is going back into production. But we can't say what that is until some cost estimate is given.

One is getting used as a wear tester, that's another saved for use, and the third... they haven't really decided yet, but they still have the thing. 

[PB666]

1 hour ago, CptRichardson said:

One is getting used as a wear tester, that's another saved for use, and the third... they haven't really decided yet, but they still have the thing. 

And they will have another piece of toast once OCISLY gets back.

 

[kunok]

19 hours ago, Kerbart said:

If the odds are good, you will roll the dice on a chance of failure. This is why SpaceX exists in the first place. ULA has the 100% success rate and the accompanying price tag. Now, if you're launching that once-in-a-lifetime science mission where you cannot afford to miss it, it's worth paying 10× what SpaceX charges. But if you're launching 4 comsats per year at $200M each then I'd rather pay $50 for a launch with 90% success than $500 for a launch with 100% success. Seriously, all that SpaceX needs to do is to establish a succesrate that is "good enough" for the price they charge.

Besides I agree with the idea itself the numbers doesn't make sense. SpaceX doesn't have a 10x difference in price, SpaceX is more expensive than you said, and even the Delta IV heavy are cheaper than what you said, if you run your example with the real numbers, SpaceX loses the competition.

This is the big dumb booster way, it could make some sense, but I feel there isn't enough market (production schedule really).

Just don't use this kind of examples, there is always people referring to 10x reduction in cost with has sense only to the the shuttle, not to any current system, and less to any that wants to be cost effective and not the most reliable possible.

[fredinno]

7 hours ago, PB666 said:

Well we expect it out of you, you want to be a rusty nail just for rust's sake. You kind of like to think of yourself as a Neanderthal. 

See responses above. However along a different set of lines......

How much did the specialized barge with 4 rather expensive pilot boat engines cost them?

How much does it cost to bring the rocket back, those enigines are horribly ineffecient for open seas travel and the design of the barges is worse still, should the contract out a pickup and transfer ship that will carry the rocket back to port. 

The cost of the barge isn't very high compared to the rocket.

4 minutes ago, kunok said:

Besides I agree with the idea itself the numbers doesn't make sense. SpaceX doesn't have a 10x difference in price, SpaceX is more expensive than you said, and even the Delta IV heavy are cheaper than what you said, if you run your example with the real numbers, SpaceX loses the competition.

This is the big dumb booster way, it could make some sense, but I feel there isn't enough market (production schedule really).

Just don't use this kind of examples, there is always people referring to 10x reduction in cost with has sense only to the the shuttle, not to any current system, and less to any that wants to be cost effective and not the most reliable possible.

Big Dumb Booster actually had high reliability. It was "dumb" for using low-tech, simpler solutions to rocketry, like pressure-fed engines.

 

15 hours ago, Nibb31 said:

Seriously? After all the explaining that we've done?

When the first stage separates from the upper stage, it is 300km from the space center's parking lot, which happens to be above the ocean, travelling at Mach 6 above the atmosphere. To get back to the parking lot requires a boostback burn to get the rocket travelling in the opposite direction, back to the launch site. This requires a surplus in propellant, which the Falcon 9 doesn't have for GTO missions. It has enough fuel to decelerate and land, but not to boost back to the launch site.

As for the extra propellant for landing, parachutes are actually heavier. Parachutes could not land you precisely enough to aim for the space center's parking lot, especially if you are descending slow enough to not damage the rocket. Parachutes (especially large custom-built ones) are expensive to make, to check, and to pack. And most importantly, parachutes will not slow you down to 0m/s and 0m altitude. They will land your fragile rocket at a constant velocity, around 20m/s, which is going to break it unless you add even more weight for airbags, retro-rockets or super strong legs, all of which are more complex and heavier than the small amount of extra propellant needed for a soft landing.

 

Well, it's not really "a small amount of propellant". It's on the number of several Tons. Parachutes aren't really heavier, just harder to reuse and more complex, going against a lot of SpaceX philosophy.

And I wonder if it would be possible for a barge to 'catch' the rocket from a parachuting rocket by moving quickly around. (the final burn would be done by the rocket's main engines, which would need to be restartable anyways).

 

Or landing a rocket horizontally with dedicated small solid landing engines, which would be designed to be "easily" detachable from the rocket.

It would slow down the rocket more, saving mass, and be more stable, though, it would cost more.

Probably best for higher-speed landings.

19 hours ago, PB666 said:

Well they got up 2 today in one launch. Maybe next time they'll do 4 at a time. 

The only real problem with the last launch, we didn't get to see it blow up on the barge. 

Those 2 satellites were designed for dual launch.

We might get a 4-satellite launch one day, but only if the satellites are small enough and designed for that. That doesn't seem to be the case for the next few launches.

[PB666]

12 minutes ago, kunok said:

Besides I agree with the idea itself the numbers doesn't make sense. SpaceX doesn't have a 10x difference in price, SpaceX is more expensive than you said, and even the Delta IV heavy are cheaper than what you said, if you run your example with the real numbers, SpaceX loses the competition.

This is the big dumb booster way, it could make some sense, but I feel there isn't enough market (production schedule really).

Just don't use this kind of examples, there is always people referring to 10x reduction in cost with has sense only to the the shuttle, not to any current system, and less to any that wants to be cost effective and not the most reliable possible.

The last failure for SpaceX was a contract failure do to inability to reach targeted velocity before circularization, falling below the safety of dV required to dock with ISS.

[fredinno]

1 hour ago, PB666 said:

The last failure for SpaceX was a contract failure do to inability to reach targeted velocity before circularization, falling below the safety of dV required to dock with ISS.

Wait, what? You mean the rocket blowing up on launch?

[PB666]

19 minutes ago, fredinno said:

Wait, what? You mean the rocket blowing up on launch?

That was quite a while back. 

This is what you are referring, second stage explosion. 

https://en.m.wikipedia.org/wiki/SpaceX_CRS-7

 

Edited June 16, 2016 by PB666