SpaceX's Big Falcon Topic 2

[Ser Scot A Ellison]

32 minutes ago, SpaceChampion said:

Ok, I'm hearing now that the initial estimates of it's orbit is wrong.  It's been corrected to:

Mars in July!  Except Mars will still be 100 million km away.  No Ceres for Starman!  Each elliptical orbit is going to take about 1.6 years, so sooner or later it will pass close to Mars.

I thought Mars was a 9 month trip?  Does this mean that with existing tech and the right alignment Mars is a 5 month trip?

[SpaceChampion]

9 minutes ago, Ser Scot A Ellison said:

I thought Mars was a 9 month trip?  Does this mean that with existing tech and the right alignment Mars is a 5 month trip?

It all depends on what velocity you are going at, and how much fuel you have to slow down.  Roadster doesn't need to slow down so it set off after exhausting its fuel.  It varies with orbital alignments too.  Most missions want to go into orbit (whether it is a satellite or a lander or rover that needs to go into orbit before descending) so cannot arrive too fast.  Using the atmosphere to slow down is an occasionally used strategy, so you can go faster.  But with the BFR, SpaceX intends for 80 to 110 day trips with humans.  So 3 to 4 months.  It's large size is an asset to using the atmo to slow down.  The bigger the ship, the more velocity it can bleed off.

[SerHaHa]

IIRC I'd read somewhere that if we can create a power source that will allow a constant thrust of 1G, Mars, regardless of where we are in respective orbits, is a pretty fast trip.  That's even with a 180 and decel @ 1 g for part of the last 1/2 of the journey.  I'll have to look it up.  As it stands now, with both the radiation, life support, and piles of other tech issues - IMO going to Mars is a pretty dangerous, and likely 1 way trip at best.  I wish we'd just return to the moon for now, and get our tech perfected with such a closer - and far safer - mission.  There is so much we can learn about setting up a base or short term expedition to the lunar surface.  It'd be worth it just for the pics of the flags and left over equipment to shut all the truthers and conspiracy nuts up.

 

edit - found the site with all the space travel time and data.  Travel time (at 9.80665 m/s², decelerating halfway): 1d 21h 13m 1s, that's the time it'd take us to get to Mars with a constant 1g thrust, which would be very comfortable for space travelers, and cut down on the 4 hours of heavy exercise they'd need to do to keep their skeleton from bleeding off.

Obviously it takes a lot more than 1g to lift off the ground much less break into orbit, but if we could design a power/fuel source or some sort of gravimetric drive that didn't require a consumable fuel, once a spacecraft is in space/orbit, it could be used at will so far as cranking up to 1g thrust from space.  I hope I live to see this technology, either created, or declassified/disclosed.

[Isalie]

Man, this is so great, and you are great for keeping the thread updated! 

[Loge]

7 hours ago, SerHaHa said:

IIRC I'd read somewhere that if we can create a power source that will allow a constant thrust of 1G, Mars, regardless of where we are in respective orbits, is a pretty fast trip.  That's even with a 180 and decel @ 1 g for part of the last 1/2 of the journey.  I'll have to look it up.  As it stands now, with both the radiation, life support, and piles of other tech issues - IMO going to Mars is a pretty dangerous, and likely 1 way trip at best.  I wish we'd just return to the moon for now, and get our tech perfected with such a closer - and far safer - mission.  There is so much we can learn about setting up a base or short term expedition to the lunar surface.  It'd be worth it just for the pics of the flags and left over equipment to shut all the truthers and conspiracy nuts up.

 

edit - found the site with all the space travel time and data.  Travel time (at 9.80665 m/s², decelerating halfway): 1d 21h 13m 1s, that's the time it'd take us to get to Mars with a constant 1g thrust, which would be very comfortable for space travelers, and cut down on the 4 hours of heavy exercise they'd need to do to keep their skeleton from bleeding off.

Obviously it takes a lot more than 1g to lift off the ground much less break into orbit, but if we could design a power/fuel source or some sort of gravimetric drive that didn't require a consumable fuel, once a spacecraft is in space/orbit, it could be used at will so far as cranking up to 1g thrust from space.  I hope I live to see this technology, either created, or declassified/disclosed.

That technology would have to use a fusion reactor as a power source. That's still many decades away, if ever happens. That's why there hasn't any real progress in the field these last 50 years, we are still stuck with the rocket technology developed in the 1950s and 60s. SpaceX can make it cheaper, but they can't change the fundamental limitations.

[Ser Scot A Ellison]

4 minutes ago, Loge said:

That technology would have to use a fusion reactor as a power source. That's still many decades away, if ever happens. That's why there hasn't any real progress in the field these last 50 years, we are still stuck with the rocket technology developed in the 1950s and 60s. SpaceX can make it cheaper, but they can't change the fundamental limitations.

Why would a fusion reactor make space flight easier?  Ultimately isn't a fusion reactor still just a heat source we use to boil water and spin a dynamo?

[Loge]

4 minutes ago, Ser Scot A Ellison said:

Why would a fusion reactor make space flight easier?  Ultimately isn't a fusion reactor still just a heat source we use to boil water and spin a dynamo?

Because you get a lot of heat out of it. With conventional fuel the weight of the fuel almost eats up all the energy / momentum it produces (cf. the rocket equation.) That's why you end up with huge rockets and small payloads. Of course, it's possible that when we finally have fusion technology it's so complicated and heavy that it can't be used in a spacecraft. 

[Which Tyler]

http://www.rugbyrebels.co/board/download/file.php?id=444

[Leofric]

32 minutes ago, Which Tyler said:

http://www.rugbyrebels.co/board/download/file.php?id=444

I likes it !!

[SpaceChampion]

Someone in Australia with a telescope caught sight of the Tesla in space!

 

Also, Lori Garver, former deputy administrator for NASA said both Air Force and NASA were offered a free ride on this debut launch, but both turned them down -- clearly a decision she didn't agree with. 

Air Force however is flying on the next Falcon Heavy launch in June.  This begins a certification process to allow FH to fly military (and I presume national security agency) payloads.

[The Anti-Targ]

11 hours ago, Loge said:

That technology would have to use a fusion reactor as a power source. That's still many decades away, if ever happens. That's why there hasn't any real progress in the field these last 50 years, we are still stuck with the rocket technology developed in the 1950s and 60s. SpaceX can make it cheaper, but they can't change the fundamental limitations.

There are propulsion technologies available (or at least with reasonably well developed on paper), but they are all too low acceleration to achieve escape velocity for ground based launches (probably even too low acceleration for ground based launches from the moon. They are probably also too low acceleration for fast trips to Mars, but these technologies have high terminal speeds which makes them suitable for deeper space travel. My brother spent a few years working in the field of space propulsion back in mid 2000s and there were a few pretty innovative concepts. But they pretty much all involved space launches rather than ground launches. So before they can be used you have to build the space infrastructure to support them.

[SerHaHa]

19 hours ago, Loge said:

That technology would have to use a fusion reactor as a power source. That's still many decades away, if ever happens. That's why there hasn't any real progress in the field these last 50 years, we are still stuck with the rocket technology developed in the 1950s and 60s. SpaceX can make it cheaper, but they can't change the fundamental limitations.

While a fusion reactor could be the solution, it certainly isn't the only option.  Some sort of system that controls gravity or harnesses energy through manipulating space/time, could work just as well.  In terms of putting thrust out of a conical housing at the rear of a vehicle, yes, fusion is probably the most likely route to eliminate the mass and volume that fuel takes up for current systems.  It's just not the only potential solution. 

 

7 hours ago, The Anti-Targ said:

There are propulsion technologies available (or at least with reasonably well developed on paper), but they are all too low acceleration to achieve escape velocity for ground based launches (probably even too low acceleration for ground based launches from the moon. They are probably also too low acceleration for fast trips to Mars, but these technologies have high terminal speeds which makes them suitable for deeper space travel. My brother spent a few years working in the field of space propulsion back in mid 2000s and there were a few pretty innovative concepts. But they pretty much all involved space launches rather than ground launches. So before they can be used you have to build the space infrastructure to support them.

You're right, and ss I said, we don't need to have an "all in one" solution for both lift off, achieving orbit, and then inter planetary travel.  We could use current methods to lift a vehicle/system, or parts of it at a time, assemble/stage it and establish it in orbit, and THEN use some whizzy new drive system to break orbit and propel it to its destination.

It would be nice though if we create (or declassify, heh) some sort of gravity controlling propulsion system that could do both - lift a vehicle from landing gear to orbit, and then on to the planets of our system, and beyond, all encapsulated in one vehicle.

[Spring Bass]

As cool as the launch was, I'm kind of sad that nobody was willing to put up a satellite for a free launch on it instead of the Tesla. A free launch is a big deal even if the rocket does have a 50/50 chance of failure. 

[Erik of Hazelfield]

This is too good not to post here:

https://i.redd.it/5xwlae0rzne01.png

[The Anti-Targ]

On 2/9/2018 at 10:47 PM, SerHaHa said:

While a fusion reactor could be the solution, it certainly isn't the only option.  Some sort of system that controls gravity or harnesses energy through manipulating space/time, could work just as well.  In terms of putting thrust out of a conical housing at the rear of a vehicle, yes, fusion is probably the most likely route to eliminate the mass and volume that fuel takes up for current systems.  It's just not the only potential solution. 

 

You're right, and ss I said, we don't need to have an "all in one" solution for both lift off, achieving orbit, and then inter planetary travel.  We could use current methods to lift a vehicle/system, or parts of it at a time, assemble/stage it and establish it in orbit, and THEN use some whizzy new drive system to break orbit and propel it to its destination.

It would be nice though if we create (or declassify, heh) some sort of gravity controlling propulsion system that could do both - lift a vehicle from landing gear to orbit, and then on to the planets of our system, and beyond, all encapsulated in one vehicle.

The thing is, who is going to be willing to put billions of dollars into developing space infrastructure to be able to launch deep space vessels without some sort of reasonable horizon for the investment to start making economic returns? So until a commitment to deep space travel is made simply because it's there or because we can someone has to come up with a business plan that has profit on the horizon for there to be the right infrastructure in orbit to achieve it. 

[Which Tyler]

43 minutes ago, Erik of Hazelfield said:

This is too good not to post here:

https://i.redd.it/5xwlae0rzne01.png

Ahem

On 08/02/2018 at 11:48 PM, Which Tyler said:

http://www.rugbyrebels.co/board/download/file.php?id=444

 

[Erik of Hazelfield]

Oh. 

http://m.quickmeme.com/img/e1/e13839eb6ef225b321b0005013a2fb16f2391604a5841543e8425d07947faa6e.jpg

[SpaceChampion]

To support landings of two FH boosters at sea (when the center core is expended) SpaceX needs a third drone ship.  They are building one called A Shortfall of Gravitas, named after another ship from Iain Bank's Culture novels.

A fully expended FH mission is now priced at $150 million.  With 3-booster recovery it is only $90 million.  Compare to a Delta IV Heavy at $400 million.  Unsurprisingly, ULA is retiring it this year due to being unable to compete on price with SpaceX.

Next launch is a F9 (last Block 3 version ever, previously flown) carrying a sat for Spain, as well as two prototype satellites for SpaceX's Starlink internet broadband project, a constellation of 8000 sats in a polar low Earth orbit that it will put up with its fleet of reusable rockets in a few years.  Static fire already done, target launch date is Feb 17, 6:17 PST from Vandenburg.

 

[Erik of Hazelfield]

Why do they need a third drone ship to land two boosters, if the center core is expended? What would the third drone ship be doing?

[Spring Bass]

6 hours ago, SpaceChampion said:

A fully expended FH mission is now priced at $150 million.  With 3-booster recovery it is only $90 million.  Compare to a Delta IV Heavy at $400 million.  Unsurprisingly, ULA is retiring it this year due to being unable to compete on price with SpaceX.

Not bad! The expendable version can put 63.8 metric tons into Low Earth Orbit, meaning a launch price of $2351/kilogram. That's a nice improvement on existing launch costs. The reusable configuration is cheaper, but I don't think it can put as much payload up with full recovery - it sounds like the per-kilogram price won't change much. 

On 2/11/2018 at 1:39 PM, The Anti-Targ said:

The thing is, who is going to be willing to put billions of dollars into developing space infrastructure to be able to launch deep space vessels without some sort of reasonable horizon for the investment to start making economic returns? So until a commitment to deep space travel is made simply because it's there or because we can someone has to come up with a business plan that has profit on the horizon for there to be the right infrastructure in orbit to achieve it. 

It's probably going to have to piggy-back off of a publicly-funded space infrastructure for those purposes (like if NASA and/or some other countries' space programs puts up a moon base down the line, with all that entails for infrastructure and technology). Either that, or they get the launch costs into space low enough that someone could design, launch, and operate a space capsule for only tens of millions of dollars (at which point you could get space missions funded by business, or by consortia of universities and private donors like with telescopes).