SpaceX FH : Falcon Heavy Demo : Feb 6, 2018 : Discussion Thread 2

[jpo234]

Oh.  It looks like a Spaceport.  Reminds me of these pictures.


The difference is, of course, both these will fly.

If we get lucky with scheduling, in the future could it be possible to get a picture with 4 vehicles all on their pads at once?  SLS on LC-39B, F9/FH on LC-39A, Atlas 5/Vulcan on SLC-41, and F9 on SLC-40.  Given SpaceX's planned high cadence and the lengthy amount of time SLS is likely to be on the pad prior to launch, the deciding factor may be ULA's schedule on SLC-41.

New Glenn at LC-36??

[.Scott]

Kabloona and LouScheffer are correct, and that is not how a Hohmann transfer orbit works ( https://en.wikipedia.org/wiki/Hohmann_transfer_orbit ). A LEO burn away from the sun (at 6pm local time, over the terminator) raises the aphelion and leaves the perihelion unchanged. Burning towards the sun (at 6am local, also over the terminator) lowers the perihelion and leaves the aphelion unchanged.

So, by simply changing the timing of the FH Demo mission injection burn to 6am local, the roadster could just as easily be sent to a Venus heliocentric orbit.

I was looking at it a bit differently.  When you apply thrust in the direction of your Earth orbit, you increase your total energy - eventually to the point of reaching escape velocity.  At that point, you have a trajectory that will take you away from Earth in some general direction.  I was mistakenly calling that the Delta-V ... a bad term since others have already used that term to refer to a more local change in the vehicle velocity.

So let me call what I am referring to as the Earth escape vector (EEV).

If your Earth escape vector is either directly towards the sun or directly away from it, for the same velocity, you will get basically the same apogee and perigee.

So the question becomes, is there an EEV that will get you a Mars-orbit apogee as efficiently or more efficiently than a Hohmann EEV?  The Hohmann scenario is the most efficient method of moving into a Mars orbit (or, more precisely, to any circular orbit) - but, as best I know, not necessarily a Mars-orbit apogee.

[hkultala]

So the question becomes, is there an EEV that will get you a Mars-orbit apogee as efficiently or more efficiently than a Hohmann EEV?  The Hohmann scenario is the most efficient method of moving into a Mars orbit (or, more precisely, to any circular orbit) - but, as best I know, not necessarily a Mars-orbit apogee.

Wrong.

Hohmann transfer orbit does not lead to mars orbit. It's exacly the most efficient method to getting to mars apogee from sun you were asking for.

[.Scott]

Hohmann transfer orbit does not lead to mars orbit. It's exactly the most efficient method to getting to mars apogee from sun you were asking for.

Thanks

[robert_d]

So the question becomes, is there an EEV that will get you a Mars-orbit apogee as efficiently or more efficiently than a Hohmann EEV?  The Hohmann scenario is the most efficient method of moving into a Mars orbit (or, more precisely, to any circular orbit) - but, as best I know, not necessarily a Mars-orbit apogee.

I think your point might be that there probably exists an elliptical orbit with a lower perihelion and a higher aphelion that has the same total energy as the Earth's orbit. Then, whether there is a way to transfer to that orbit with less energy than required for the Hohmann transfer. Or: is it possible to trade the energy from the lower half to the upper? I don't think so because, as has been pointed out, It is not possible to GAIN energy from changing the perihelion when starting at Earth. A spacecraft actually has to expend energy to COUNTER the energy contained in an Earth-distance orbit. Thus Hohmann must be the most efficient to reach Mars distance aphelion. With the corollary that it then requires the LEAST energy to circularize.  A spacecraft in a highly elliptical orbit with an aphelion at Mars would be moving very slowly in relation to Mars.

[leetdan]

If the trajectory is lofted enough for the center core to ballistically land 100km offshore, will its reentry burn be visible from shore?

[Jim]

If the trajectory is lofted enough for the center core to ballistically land 100km offshore, will its reentry burn be visible from shore?

The 100km was a mistake.

[Kabloona]

If the trajectory is lofted enough for the center core to ballistically land 100km offshore, will its reentry burn be visible from shore?

ASDS position will be approximately 345 km / 215 miles downrange.

[deruch]

If we get lucky with scheduling, in the future could it be possible to get a picture with 4 vehicles all on their pads at once?  SLS on LC-39B, F9/FH on LC-39A, Atlas 5/Vulcan on SLC-41, and F9 on SLC-40.  Given SpaceX's planned high cadence and the lengthy amount of time SLS is likely to be on the pad prior to launch, the deciding factor may be ULA's schedule on SLC-41.

DIVH should still be launching from 37 as well in 2019-2022.

New Glenn at LC-36??

So, if we get very, very lucky with scheduling and rocket development, maybe we'll get a pic with 6+ vehicles.  **Awesomeness increases**

[speedevil]

So, if we get very, very lucky with scheduling and rocket development, maybe we'll get a pic with 6+ vehicles.  **Awesomeness increases**

If we get very lucky, we won't notice.

[SergeyUser]

Can anyone advice on specific security procedures on the launch day? Placard sent by KSC says "Arrive 6 hours before scheduled launch time". At the same time, KSC says "busses to Apollo 5/Saturn center start delivering visitors 3 hours before launch time".

So how does this practically work? Can I arrive by car 4 hours before launch using the Placard, and still be allowed to enter? Would I have any issues passing through security gates, etc.? Please advice.

[The_Ronin]

Can anyone advice on specific security procedures on the launch day? Placard sent by KSC says "Arrive 6 hours before scheduled launch time". At the same time, KSC says "busses to Apollo 5/Saturn center start delivering visitors 3 hours before launch time".

So how does this practically work? Can I arrive by car 4 hours before launch using the Placard, and still be allowed to enter? Would I have any issues passing through security gates, etc.? Please advice.

You basically hang out at the visitor center until they start loading the busses.  Go visit the rocket garden and relax a bit but keep on eye on the bus queue.  For STS-134 Causeway, they started lining up about 90 minutes before the busses started to run.  Also, if it is anything like STS-134, the parking lot will fill fast, so waiting until 4 hours before launch could mean parking WAY far from the gate, a hoof in, and being at the end of bus queue.

[Boost]

How to interpret this about Playalinda ? If it's possible to watch the launch from the road, it should be as close as the press/VIP site.

[SergeyUser]

Can anyone advice on specific security procedures on the launch day? Placard sent by KSC says "Arrive 6 hours before scheduled launch time". At the same time, KSC says "busses to Apollo 5/Saturn center start delivering visitors 3 hours before launch time".

So how does this practically work? Can I arrive by car 4 hours before launch using the Placard, and still be allowed to enter? Would I have any issues passing through security gates, etc.? Please advice.

You basically hang out at the visitor center until they start loading the busses.  Go visit the rocket garden and relax a bit but keep on eye on the bus queue.  For STS-134 Causeway, they started lining up about 90 minutes before the busses started to run.  Also, if it is anything like STS-134, the parking lot will fill fast, so waiting until 4 hours before launch could mean parking WAY far from the gate, a hoof in, and being at the end of bus queue.

Thanks! So that means they will still allow cars to enter, at least sometime *after* ([Launch time] - 6 hours)? I assume this is correct, but I wanted to double check..

Also, is anyone aware who will be the person mentioned on the page (https://www.kennedyspacecenter.com/launches-and-events/events-calendar/falcon-heavy-launches#FeelTheHeat)?

"You will also have the opportunity to hear from a special guest in a live presentation."

[cscott]

Also, is anyone aware who will be the person mentioned on the page (https://www.kennedyspacecenter.com/launches-and-events/events-calendar/falcon-heavy-launches#FeelTheHeat)?

"You will also have the opportunity to hear from a special guest in a live presentation."

My guess would be one of the astronauts they have on-call for astronaut appearances ( https://www.kennedyspacecenter.com/launches-and-events/events-calendar?categories=Astronaut%20Appearances )
but they don't want to commit to a specific one in case the launch is delayed or rescheduled.

But of course it could be anyone, maybe even Harrison Ford.

[ZachF]

SES-16 is now clear, which means we've finally gone from six months™, to next week/next launch now. 

[Rocket Science]

How to interpret this about Playalinda ? If it's possible to watch the launch from the road, it should be as close as the press/VIP site.

It's a good spot, just make note of the restrictions...

[Kabloona]

But of course it could be anyone, maybe even Harrison Ford.

That was actually my first thought, especially if Musk had a hand in it.

[intrepidpursuit]

How to interpret this about Playalinda ? If it's possible to watch the launch from the road, it should be as close as the press/VIP site.

Sounds like they will be counting cars and limiting the number. So carpool and get there early.

[Lar]

SES-16 is now clear, which means we've finally gone from six months™, to next week/next launch now. 

FH is not necessarily the next launch. If there are significant issues between now and when the next paying launch  is manifested for, I am sure that SpaceX will reorder. But yeah, it's feeling very real.