Author Topic: Could a Falcon 9R fly to 100km altitude and land back?  (Read 21367 times)

Offline aceshigh

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I donīt know how much media and the general population perception is important to a company like SpaceX, which in the end, doesnīt really deal with the general public.

All the while, Blue Origin plans to sell suborbital tourist flights. So marketing is more important to them.

But if marketing is important to SpaceX too, I wonder if the F9R they did those 1000m flights could be used for a 100km flight and then land back. In the short term.

Send a F9R to do the same thing as the Blue Origin rocket in a short term from now, then prepare a press conference to EDUCATE people on the differences between reaching space and reaching orbit, and how much more difficult is to land a rocket coming from a horizontal speed of 30 thousand kilometers per hour on a barge on the middle of the ocean to land a rocket flying straight up and down.


CNN was basically MOCKING SpaceX for BlueOrigin doing it "first" than SpaceX while the F9 crashed. As if they were the same thing.

And Musk tweet will fall on deaf and ignorant ears.


So, would the F9R prototype or the Grasshopper be capable of after short adaptations fly to 100km altitude??

Offline joek

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Re: Could a Falcon 9R fly to 100km altitude and land back?
« Reply #1 on: 11/25/2015 12:59 AM »
So, would the F9R prototype or the Grasshopper be capable of after short adaptations fly to 100km altitude??

That was the original plan: to fly, or re-fly an F9R booster to ~100km from Spaceport America.  We still may see it, but SpaceX apparently decided those early tests were better served by their current approach: piggy-backing on existing launches with ASDS recovery.
« Last Edit: 11/25/2015 01:01 AM by joek »

Online Robotbeat

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Re: Could a Falcon 9R fly to 100km altitude and land back?
« Reply #2 on: 11/25/2015 01:00 AM »
Yes, as long as it was mounted like a typical F9 launch and had a nosecap of some sort attached.

Should be a piece of cake, actually. On the way down, they should have enough delta-v left over that they could stay below Mach 1, basically "hovering" all the way down to the ground.
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Offline laika_fr

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Re: Could a Falcon 9R fly to 100km altitude and land back?
« Reply #3 on: 11/25/2015 01:11 AM »
Of course it could, but they may be planning a different type of rocket/engine to do so ...

Has previously said SpaceX took a different path over the years and spaceport america was not required anymore.
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Online Johnnyhinbos

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Re: Could a Falcon 9R fly to 100km altitude and land back?
« Reply #4 on: 11/25/2015 01:30 AM »
I would think everyone in the "Elon stated that the stage is flying back from the barge to mainland as part of the reuse program" camp would have an opinion on this one.

Personally I feel that SpaceX has the tech maturity to accomplish this, but it would come across as a bit pedantic.

Instead I'd prefer SpaceX focus on its business plan and not be bothered by such distractions, which I'm sure is exactly what it's doing.

Today was a fantastic day in the space industry. We all should pause and marvel at the achievement. My hats off to Blue Origin!

At the same time, do you really suppose SpaceX has put all plans and development on pause during the RTF hold? Do you think that they've not continued to make improvements to their systems from avionics to additive manufacturing during this time? Of course they have. It's an exciting time right now, and I for one can't wait what December will bring...
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Offline aceshigh

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Re: Could a Falcon 9R fly to 100km altitude and land back?
« Reply #5 on: 11/25/2015 01:32 AM »
Yes, as long as it was mounted like a typical F9 launch and had a nosecap of some sort attached.

Should be a piece of cake, actually. On the way down, they should have enough delta-v left over that they could stay below Mach 1, basically "hovering" all the way down to the ground.

yes, but my question is more regarding if it would be possible to do it on the short term, just to show the media "if we wanted to do something as simple as that, we would already have done it".

and for the short term, it would be a question of : does the F9R used on those tests (1000m high maximum or there was one that went higher?) is still available? Why didnīt they made any other tests with more altitude? I agree that specifically for SpaceX, there was no use (not their market) , but wasnīt that F9R maybe done JUST for those tests and lacked some components for higher altitudes?

could SpaceX just come in 2 weeks and beat Blue Origin if they wanted? Or would they need much more time for such test?

Offline aceshigh

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Re: Could a Falcon 9R fly to 100km altitude and land back?
« Reply #6 on: 11/25/2015 01:34 AM »
I would think everyone in the "Elon stated that the stage is flying back from the barge to mainland as part of the reuse program" camp would have an opinion on this one.

Personally I feel that SpaceX has the tech maturity to accomplish this, but it would come across as a bit pedantic.

Instead I'd prefer SpaceX focus on its business plan and not be bothered by such distractions, which I'm sure is exactly what it's doing.

Today was a fantastic day in the space industry. We all should pause and marvel at the achievement. My hats off to Blue Origin!

At the same time, do you really suppose SpaceX has put all plans and development on pause during the RTF hold? Do you think that they've not continued to make improvements to their systems from avionics to additive manufacturing during this time? Of course they have. It's an exciting time right now, and I for one can't wait what December will bring...

And I quite frakked actually. It was a good achievement by Blue Origins.

But Bezzos media statement made it seem much more than it really was and the media and public swallowed it all! They are comparing DIRECTLY between SpaceX failed Falcon9 landing and Blue Origin landing.

Offline eriblo

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Re: Could a Falcon 9R fly to 100km altitude and land back?
« Reply #7 on: 11/25/2015 02:32 AM »
Yes, as long as it was mounted like a typical F9 launch and had a nosecap of some sort attached.

Should be a piece of cake, actually. On the way down, they should have enough delta-v left over that they could stay below Mach 1, basically "hovering" all the way down to the ground.

yes, but my question is more regarding if it would be possible to do it on the short term, just to show the media "if we wanted to do something as simple as that, we would already have done it".

and for the short term, it would be a question of : does the F9R used on those tests (1000m high maximum or there was one that went higher?) is still available? Why didnīt they made any other tests with more altitude? I agree that specifically for SpaceX, there was no use (not their market) , but wasnīt that F9R maybe done JUST for those tests and lacked some components for higher altitudes?

could SpaceX just come in 2 weeks and beat Blue Origin if they wanted? Or would they need much more time for such test?
I don't really feel the need for one-upmanship but I believe the answer to your questions are:

Maybe, technically, but no because of red tape. 2 x It blew up. Don't think so. 2 x See answer 1.

F9R-Dev was designed to do this, but had to terminate (save the cows!) on one of the test flights building up to this. (I think that Grasshopper is too heavy to reach 100 km). Both the last F9 1.1 and the RTF F9FT first stage could easily do this and might be ready in two weeks, but it would have to be from Spaceport America and we haven't heard that the ground equipment is ready (and they don't have an active permit AFAIK). Technically it might be possible to truck Jason 3's stage to McGregor, treat it as a F9R-Dev and launch it (although it would likely need to much modification). It would also kill the company and fill a prison block or two.

IMHO, what they are going to do is this: take the RTF F9FT stage and, maybe as soon as three weeks from now, launch it from Florida both higher and and faster while weighted down for sport. Then they are going to land it on a barge as described in some patent (after asking nicely one last time if they might not land it at the launch site instead). And get a big check for it as well.

Offline Elmar Moelzer

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Re: Could a Falcon 9R fly to 100km altitude and land back?
« Reply #8 on: 11/25/2015 02:42 AM »
From what I remember, the apogee of the F9 first stage during a normal orbital launch trajectory (with first stage recovery) is 160 km. Mind you that at stage separation, the it is also very far down range and has a very high horizontal velocity (Mach 6, IIRC). So it should easily(!) be able to go up to 100 km and come straight down again. In fact, according to Elon Musk, the first stage alone could do SSTO (but with zero payload).
Either way, the exercise seems rather pointless, since the stage is already coming back from an altitude way above the karman line, even during normal launches (with recovery).
« Last Edit: 11/25/2015 02:46 AM by Elmar Moelzer »

Offline shuttlelegs

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Re: Could a Falcon 9R fly to 100km altitude and land back?
« Reply #9 on: 11/25/2015 04:36 AM »
What height did the DC-X ever get to ?



Offline RonM

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Offline spacefairer

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Re: Could a Falcon 9R fly to 100km altitude and land back?
« Reply #11 on: 11/25/2015 05:37 AM »
Not yet.  They still need to figure out how to land.  Its tricky I hear.

Offline Paul_G

Yes, as long as it was mounted like a typical F9 launch and had a nosecap of some sort attached.

Should be a piece of cake, actually. On the way down, they should have enough delta-v left over that they could stay below Mach 1, basically "hovering" all the way down to the ground.

Isn't the thrust/weight ratio too high for this - this is why we have the hover slam manoeuvre in the first place - you can't continuously fire the engine as the stage would rise up again.

Out of interest do we know the descent profile of Blue Origin - how many burns does it make on the way down?

Paul

Online Coastal Ron

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Re: Could a Falcon 9R fly to 100km altitude and land back?
« Reply #13 on: 11/25/2015 05:47 AM »
Not yet.  They still need to figure out how to land.  Its tricky I hear.

Landing on land back at your launch point is relatively easy.  SpaceX has already demonstrated the ability to do that.  Landing on a small barge at sea after launching from hundreds of miles away and pushing a payload into a precise orbit - that is a lot harder.
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Offline funkyjive

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Re: Could a Falcon 9R fly to 100km altitude and land back?
« Reply #14 on: 11/25/2015 06:00 AM »
Yes, as long as it was mounted like a typical F9 launch and had a nosecap of some sort attached.

Should be a piece of cake, actually. On the way down, they should have enough delta-v left over that they could stay below Mach 1, basically "hovering" all the way down to the ground.

Isn't the thrust/weight ratio too high for this - this is why we have the hover slam manoeuvre in the first place - you can't continuously fire the engine as the stage would rise up again.

Out of interest do we know the descent profile of Blue Origin - how many burns does it make on the way down?

Paul
A single landing burn.

Offline spacefairer

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Re: Could a Falcon 9R fly to 100km altitude and land back?
« Reply #15 on: 11/25/2015 06:07 AM »
Not yet.  They still need to figure out how to land.  Its tricky I hear.

Landing on land back at your launch point is relatively easy.  SpaceX has already demonstrated the ability to do that.  Landing on a small barge at sea after launching from hundreds of miles away and pushing a payload into a precise orbit - that is a lot harder.

spacex has only ever landed a rocket that has been going relatively slow, a hundred km/h or so.  Quickly going from supersonic to landing is the tricky part.  There have been dozens of short hop rockets that have demonstrated VTOL, its the descent speed that makes 100 km tricky.

-edit- removed an extraneous 'if'
« Last Edit: 11/25/2015 06:25 AM by spacefairer »

Online guckyfan

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Re: Could a Falcon 9R fly to 100km altitude and land back?
« Reply #16 on: 11/25/2015 06:57 AM »
SpaceX could do it with Falcon 9R but they have little interest to do so. They had it planned but then switched to testing with spent stages of orbital flights. Their present plan is to use flown stages for that kind of test. I doubt they will change that plan just to show they can do it similar to Blue Origin.

It has been pointed out that Blue and the Falcon 9R go through not too much different speed ranges. But it is still very, very different. Falcon 9R is a part of an orbital vehicle with razor thin margins and those margins are not getting better through reuse. So they cannot afford hover.

The Blue vehicle in contrast has as much margin as the engineers care to give it and they made generous use of that as the hover and traverse close to the ground shows.

Offline Lumina

Fuel margin is a big deal. Hovering just above the ground fixes all control loop problems that software could not fix in real-time just before. So it's really apples and oranges just on that dimension. The only way to have plenty of fuel margin is to specify a rocket that is too big for its payload task.

There was another factor making it easier for BO to nail the landing. The day and time of the New Shepard flight seems to have been cherry-picked for zero ground-level crosswind at the BO private landing site. See the stationary billowing landing dust cloud in the video here: https://www.youtube.com/watch?v=9pillaOxGCo?t=123.

Low altitude crosswinds further complicate vertical propulsive pinpoint landings, so BO naturally eliminated the crosswind by launching according to a weather forecast. However, for SpaceX a station-keeping barge out in the ocean is virtually guaranteed to have crosswinds and in any case, they can't cherry pick the date of launch.
« Last Edit: 11/25/2015 08:35 AM by Lumina »

Offline tleski

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Re: Could a Falcon 9R fly to 100km altitude and land back?
« Reply #18 on: 11/25/2015 11:51 AM »
A pretty decent article in The Verge discussing why Blue Origin's  landing should not be compared with attempts to recover the first stage of F9:

http://www.theverge.com/2015/11/24/9793220/blue-origin-vs-spacex-rocket-landing-jeff-bezos-elon-musk

According to them the F9's first stage reaches the altitude of 124 miles with speeds between 5.5 to 7.5 Mach, which is a lot of energy to dissipate on its way back to the Earth's surface.
I personally don't think SpaceX needs to replicate Blue's experiment just to prove the point.

Offline Jim

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Re: Could a Falcon 9R fly to 100km altitude and land back?
« Reply #19 on: 11/25/2015 01:45 PM »
I donīt know how much media and the general population perception is important to a company like SpaceX, which in the end, doesnīt really deal with the general public.

All the while, Blue Origin plans to sell suborbital tourist flights. So marketing is more important to them.

But if marketing is important to SpaceX too, I wonder if the F9R they did those 1000m flights could be used for a 100km flight and then land back. In the short term.

Send a F9R to do the same thing as the Blue Origin rocket in a short term from now, then prepare a press conference to EDUCATE people on the differences between reaching space and reaching orbit, and how much more difficult is to land a rocket coming from a horizontal speed of 30 thousand kilometers per hour on a barge on the middle of the ocean to land a rocket flying straight up and down.


CNN was basically MOCKING SpaceX for BlueOrigin doing it "first" than SpaceX while the F9 crashed. As if they were the same thing.

And Musk tweet will fall on deaf and ignorant ears.


So, would the F9R prototype or the Grasshopper be capable of after short adaptations fly to 100km altitude??

Don't see what the problem is here.   Spacex is also known for stretching the truth.  And the actual speeds do really matter,  it is only a difference in propellant carried.
« Last Edit: 11/25/2015 01:45 PM by Jim »

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