SpaceX moon landing.

[Cloakedwand72]

Can the Dragon V2 land on the moon & also ascent from the moon & return to the earth after a few Falcon Heavy launches if the BFR is delayed?

[Bill Phil]

Probably not.

Landing takes like 2 km/s (maybe more like 1.8 or so) and taking off takes about as much. And that's just to low lunar orbit. 

So... nope. 

Not to say that something couldn't be developed, but BFR is already in development.

[kerbiloid]

Dragon v2 total delta-V budget would be
+ ~100 m/s for orbital maneuvering and docking/berthing
+ ~100 m/s to deorbit
+ ~150 m/s of terminal velocity on landing
+ ~100 m/s of gravity loss and side maneuvering (Say, 4 g acceleration on landing, so 150/((4 - 1) * 9.81) = 5 s of lowering + 1 s of hovering = at least 6 s of active landing duration,  >= 6 * 10 = 60 m/s of gravity loss)
I.e. ~450 m/s in total.

Launch abort test gives iirc 6 g for 6 s ~= 360 m/s.

So, Dragon v2 delta-V is probably ~400 m/s.

Lunar orbital speed ~1600 m/s

So, Moon landing: > 1600 m/s,
Escaping from low near-Moon orbit = 1600 * (sqrt(2) - 1) = 660 m/s.

So, it couldn't neither land, nor escape from the orbit.

P.S.
But once being on the Moon, it could jump (400/2)²/(2*1.62) = 12.4 km high and land back

Edited August 16, 2018 by kerbiloid

[Cloakedwand72]

8 minutes ago, kerbiloid said:

Dragon v2 total delta-V budget would be
+ ~100 m/s for orbital maneuvering and docking/berthing
+ ~100 m/s to deorbit
+ ~150 m/s of terminal velocity on landing
+ ~100 m/s of gravity loss and side maneuvering (Say, 4 g acceleration on landing, so 150/((4 - 1) * 9.81) = 5 s of lowering + 1 s of hovering = at least 6 s of active landing duration,  >= 6 * 10 = 60 m/s of gravity loss)
I.e. ~450 m/s in total.

Launch abort test gives iirc 6 g for 6 s ~= 360 m/s.

So, Dragon v2 delta-V is probably ~400 m/s.

Lunar orbital speed ~1600 m/s

So, Moon landing: > 1600 m/s,
Escaping from low near-Moon orbit = 1600 * (sqrt(2) - 1) = 660 m/s.

So, it couldn't neither land, nor escape from the orbit.

P.S.
But once being on the Moon, it could jump (400/2)²/(2*1.62) = 12.4 km high and land back

Ok cool. But what if they did a two crew job & had the trunk attached with a bit more fuel after a few modifications would it then be able to do it bye customer request with redundancy if had some problem?  

[kerbiloid]

To leave the Moon they need at least
1600 * sqrt(2) ~= 2300 m/s of escape speed
~50 m/s for transfer trajectory correction
+gravity losses,
so at least ~2600 m/s

-200 m/s they have for orbiting and deorbiting in usual flight

So, ~2.4 km/s of additional delta-V.
ISP*g ~= 3 km/s.

Additional mass ~= (exp(2.4/3) - 1) * 1.1 ~= 1.35 their current total mass.

I.e. ~15 t of full-size ascent stage (as they can't land on a trunk, their legs are too short).

Edited August 16, 2018 by kerbiloid

[Cloakedwand72]

13 minutes ago, kerbiloid said:

To leave the Moon they need at least
1600 * sqrt(2) ~= 2300 m/s of escape speed
~50 m/s for transfer trajectory correction
+gravity losses,
so at least ~2600 m/s

-200 m/s they have for orbiting and deorbiting in usual flight

So, ~2.4 km/s of additional delta-V.
ISP*g ~= 3 km/s.

Additional mass ~= (exp(2.4/3) - 1) * 1.1 ~= 1.35 their current total mass.

I.e. ~15 t of full-size ascent stage (as they can't land on a trunk, their legs are too short).

What if they sent a Gemini like Spacecraft on the Falcon 9 Block V https://www.google.com/search?tbm=isch&sa=1&ei=2_90W633FoOB5wLcsK7YAw&q=eclipse+space+craft+gemini&oq=eclipse+space+craft+gemini&gs_l=img.3...11299.20385.0.20673.28.26.1.1.1.0.92.1630.26.26.0....0...1c.1.64.img..0.16.1003...0j0i67k1j0i30k1j0i5i30k1j0i8i30k1.0.3UtQostzhMQ#imgrc=s8AAaCvbo-Q6lM:

Then send something like this on a Falcon Heavy Block V upgrade  with a lander like this https://www.google.com/url?sa=i&source=images&cd=&cad=rja&uact=8&ved=2ahUKEwiwmtnk4PDcAhVlplkKHXzXA4sQjhx6BAgBEAM&url=https%3A%2F%2Fwww.space.com%2F21147-pumpkin-moon-lander-golden-spike.html&psig=AOvVaw3jIFvqo1Qawn2SJZ46ZbsU&ust=1534480731870865

Then send another Falcon Heavy with Tug with a vacuum engine that can retract & extend then the two dock in Leo then go to moon orbit?

[kerbiloid]

17 minutes ago, Cloakedwand72 said:

What if they sent a Gemini like Spacecraft

http://www.astronautix.com/g/geminilunarlander.html

http://www.astronautix.com/g/geminilunargemini.html

As long as Falcon can deliver 19 t to the Moon.
So FH, not F9.

[magnemoe]

3 hours ago, kerbiloid said:

http://www.astronautix.com/g/geminilunarlander.html

http://www.astronautix.com/g/geminilunargemini.html

As long as Falcon can deliver 19 t to the Moon.
So FH, not F9.

That uses an gemini capsule however. Direct decent is always more expensive as you has to land and take of with you heat shield. 
Has been some speculations if you could do an Apollo type mission with two falcon heavy. 
You would need to replace the trunk of the dragon with an stage with storable fuel for getting into Moon orbit and back. 
Second falcon heavy holds an Apollo class lander, the one used was 16 ton but did not had to enter moon orbit by itself as the Apollo service module did that burn. 

[kerbiloid]

15 minutes ago, magnemoe said:

Direct decent is always more expensive as you has to land and take of with you heat shield. 

No.
Only until your separated cabin, docking equipment, and double life support weights less than the fuel required to land and launch the whole capsule.

 

Reliability is another question.
Of course, a double set of equipment has allowed Apollo-13 to survive.
But
1) If speak about mass and energy, that was not the lightest way. Gemini lander was lighter.
2) The more parts number, the more parts to break. If Apollo was a single craft and weighted twice less, its balloons were twice smaller, nobody would drop them, and no accident would happen at all.

[magnemoe]

2 minutes ago, kerbiloid said:

No.
Only until your separated cabin, docking equipment, and double life support weights less than the fuel required to land and launch the whole capsule.

 

Reliability is another question.
Of course, a double set of equipment has allowed Apollo-13 to survive.
But
1) If speak about mass and energy, that was not the lightest way. Gemini lander was lighter.
2) The more parts number, the more parts to break. If Apollo was a single craft and weighted twice less, its balloons were twice smaller, nobody would drop them, and no accident would happen at all.

It was lighter, did not know, on the other hand it was also less capable, an backup plan if docking around moon was too hard, don't think they had docked yet. 
It would also require an saturn 5, with docking in moon orbit you can brake up the payload into two parts. 

[kerbiloid]

13 minutes ago, magnemoe said:

It was lighter, did not know, on the other hand it was also less capable,

In sense of moon walkers it was as capable as Apollo.
The 3rd crewman on Apollo was required only because of lunar rendez-vous&docking scheme. It was absolutely excessive for lunar landing (i.e from pov of the whole expedition purpose).

Though of course, Apollo and LEM were more comfortable to live in.
But Gemini record is 14 days, so 7-8 days flight is appropriate.
(Also they could have a walk and pour out their waste bucket, unlike orbital Gemini crews.)

13 minutes ago, magnemoe said:

It would also require an saturn 5, with docking in moon orbit you can brake up the payload into two parts. 

Near-moon docking was maybe the the most unstable part of the plan.
And it was required only because of splitting Apollo in two parts.
Without that they would need no docking at all (neither near-Earth with LEM, nor near-Moon with its cabin). They would even need no docking equipment, no passage tunnel, no spermwhale-looking 2nd stage.
While the result would be the same: 2 humans on the Moon and 2 buckets of stones.

No Saturn-5. Just something ~40t.

Edited August 16, 2018 by kerbiloid

[Nibb31]

The early Apollo Direct Ascent mission architecture required the Nova rocket, which was much larger that the Saturn V.

Basically it required landing the Apollo CSM onto the lunar surface, which required a much larger descent module, which required a much larger upper stage, etc...

The Gemini lunar lander was never seriously considered. It was too cramped and would have been extremely awkward to provide landing visibility and to EVA from on the lunar surface.

 

Edited August 16, 2018 by Nibb31

[kerbiloid]

5 minutes ago, Nibb31 said:

The early Apollo Direct Ascent mission architecture required the Nova rocket, which was much larger that the Saturn V.

The Apollo 3-man.

While a 75% scaled Apollo 2-man required Saturn C-5 and 40 t sent to the moon.
http://www.astronautix.com/a/apollodirect2-man.html

Gemini was even lighter than 75% Apollo.

[Nibb31]

Yes, too cramped, poor landing visibility, and poor EVA capability.

With its dedicated LM, the LOR mission profile was much more capable.

Back to SpaceX, landing a Dragon 2 on the Moon would look a lot like the Apollo Direct Ascent vehicle I posted above. You would be better off landing the BFR.

Note that a BFR lunar landing would also require several refuel missions before the TLI burn.

Edited August 16, 2018 by Nibb31

[kerbiloid]

7 minutes ago, Nibb31 said:

too cramped,

Yes, per angusta ad augusta.
It was enough capable to fly for 8-14 days inside the ship as they did irl.

So, poor visibility is indeed bad, but why not select a proper landing site with no big stones, unlike they did with Apollo-11?
And first send 1-2 lightweight unmanned probes for that. As Gemini lander requires 2-3 times lighter rocket, you can send 2-3 ships by the price of one. Or 1 ship and a whole pack of probes.

Also we should remember Gemini-B with its door in the bottom.
They could even have a Soyuz-like habitat, leaving it on the Moon.

Edited August 16, 2018 by kerbiloid

[Cassel]

7 hours ago, Cloakedwand72 said:

Can the Dragon V2 land on the moon & also ascent from the moon & return to the earth after a few Falcon Heavy launches if the BFR is delayed?

You mean manned landing? I was wondering about first cargo Dragon and unmanned landing on Moon, would that be possible?

[kerbiloid]

Unlikely RCS engines of cargo Dragon can produce several tonnes of thrust.

[linuxgurugamer]

1 hour ago, kerbiloid said:

Yes, per angusta ad augusta.
It was enough capable to fly for 8-14 days inside the ship as they did irl.

So, poor visibility is indeed bad, but why not select a proper landing site with no big stones, unlike they did with Apollo-11?
And first send 1-2 lightweight unmanned probes for that. As Gemini lander requires 2-3 times lighter rocket, you can send 2-3 ships by the price of one. Or 1 ship and a whole pack of probes.

Also we should remember Gemini-B with its door in the bottom.
They could even have a Soyuz-like habitat, leaving it on the Moon.

Better read up on Apollo 11.  Thr original landing sight was level and clear of rocks.  They overshot it be about 11km because of the computer problems they had on the way down.

And that is why you want a more capable vessel, to have the capability to deal with unexpected circumstances.

Thing of all the safetry systems in modern cars.  They aren’t necessary to have the car do it’s thing, but are there for the unexpected.  Given the safetry of modern cars, would you willingly purchase a car with the same systems as from the 50’s?

[kerbiloid]

9 minutes ago, linuxgurugamer said:

Given the safetry of modern cars, would you willingly purchase a car with the same systems as from the 50’s?

Mercury, Gemini, Apollo had LES. _{(At least ejection seats. But more than nothing.)}
1970s-80s Shuttles - didn't. ..
Modern BFS...

9 minutes ago, linuxgurugamer said:

 They overshot it be about 11km

Several more tonnes of fuel would allow them hover and get back.
Gemini lander could have this additional propellant with a twice lighter rocket. Much greater delta-V for landing.
Apollo lander couldn't have at all.

Edited August 16, 2018 by kerbiloid

[linuxgurugamer]

Just now, kerbiloid said:

Mercury, Gemini, Apollo had LES.
1970s-80s Shuttles - didn't. ..
Modern BFS...

The Shuttles and BFS have a huge number of safety systems.  Speak to @EJ_SA for details, he is an expert on the shuttle.  As technology evolved, so did the safety systems.

1 minute ago, kerbiloid said:

Several more tonnes of fuel would allow them hover and get back.
Gemini lander could have these additional propellant with a twice lighter rocket.
Apollo lander couldn't have at all.

The Gemini lander as proposed didn't require the Saturn V.  Now you are adding in several tons of propellant, which would then have required the development of something close to the Saturn V, with less capability.

[kerbiloid]

4 minutes ago, linuxgurugamer said:

The Shuttles and BFS have a huge number of safety systems. 

I'm afraid, 2/5 ships, 2/140 flights.
While none of Mercury, Gemini, Apollo were lost. And additionally they had LES.

4 minutes ago, linuxgurugamer said:

The Gemini lander as proposed didn't require the Saturn V.  Now you are adding in several tons of propellant, which would then have required the development of something close to the Saturn V, with less capability.

Apollo was already carying this additional propellant but spent it all in orbit. 
While direct ascent Gemini could use it on landing (and still require much lighter rocket).

Edited August 16, 2018 by kerbiloid

[linuxgurugamer]

4 minutes ago, kerbiloid said:

I'm afraid, 2/5 ships, 2/140 flights.
While none of Mercury, Gemini, Apollo were lost. And additionally they had LES.

If you are going to quote the number of flight, then you should also say:

• Mercury:  6 flights
• Gemini: 19 launches, consisting of 2 unmanned, flights, 7 target vehicles and 10 crewed missions.  2 Agena's exploded during launch.  One Agena failure in orbit (shroud separation failure). One Agena failure in orbit (defective engine).  One mission aborted due to a stuck thruster on Gemini
• Apollo (lunar):  3 astronauts lost due to fire on the pad during a test.  11 flights.  One disaster in flight (Apollo 13).  
• Apollo (Skylab):  Failure during Skylab launch led to delays and emergency repairs in orbit. 4 manned flights

There were countless other near disasters which require more time to dig up than I have right now.  There were 4x as many  shuttle missions than all the manned Mercury, Gemini, and Apollo combined.

The fact that the Shuttle had two fatal accidents in flight has led to a reevaluation of what safety systems are needed.

Dragon has built-in thrusters which are the LES.  The Starliner has some sort of pusher abort system.

[Xd the great]

25 minutes ago, kerbiloid said:

I'm afraid, 2/5 ships, 2/140 flights.
While none of Mercury, Gemini, Apollo were lost. And additionally they had LES.

Apollo was already carying this additional propellant but spent it all in orbit. 
While direct ascent Gemini could use it on landing (and still require much lighter rocket).

The BFS has 4 vacuum and 2 or 3 atmo engines. The 4 vacuums may be spared, i.e. if one breaks switch it and the one diagonally away from it off.

[kerbiloid]

26 minutes ago, linuxgurugamer said:

If you are going to quote the number of flight, then you should also say:

• Mercury:  6 flights
• Gemini: 19 launches, consisting of 2 unmanned, flights, 7 target vehicles and 10 crewed missions.  2 Agena's exploded during launch.  One Agena failure in orbit (shroud separation failure). One Agena failure in orbit (defective engine).  One mission aborted due to a stuck thruster on Gemini
• Apollo (lunar):  3 astronauts lost due to fire on the pad during a test.  11 flights.  One disaster in flight (Apollo 13).  
• Apollo (Skylab):  Failure during Skylab launch led to delays and emergency repairs in orbit. 4 manned flights

I count only real crewed flights and fatal accidents.
As we can see, when people are on board, the statistics differs very much.

Apollo-1 is hardly a sample as it was just a ground training, not a real launch.
Skylab Apollos had problems, but Shuttles had them almost every second flight according to chronicles, too. So, they aren't accidents.

26 minutes ago, linuxgurugamer said:

Dragon has built-in thrusters which are the LES.

Providing 6 g acceleration in LES test. While other crafts' LES provide 12..18 g. 
So, maybe that's enough but better not check.

Also spending fuel as LES leaves Dragon without fuel for landing, making it to have a chute. But the chute makes the rocket landing ability a little excessive.
Also if it would begin braking at a chute altitude, it would spend tonnes of fuel just keeping landing.
While if it ignites the engine enough low just to brake and land, it has not enough altitude to open the chute.

So, it has to have 8 engines at once to switch off an opposite pair if something happens, and hope that nothing will happen except an engine failure.
Though if one engine bursts, it probably will damage the engine aside, so the craft should switch of 4 engines and land on opposite 2x2 engines trying not to overturn.

NASA were very right when they prohibited this rocket landing and required the chute-only water landing.

And this makes that rocket capsule idea having not much sense compared to a simple rocket engine and simple tanks set in the trunk (i.e. using a traditional scheme with propulsion module)

26 minutes ago, Xd the great said:

The BFS has 4 vacuum and 2 or 3 atmo engines. The 4 vacuums may be spared, i.e. if one breaks switch it and the one diagonally away from it off.

But this is not real escape system.
Both Shuttle and BFS (and Buran) use the same equipment for normal flight and for escape. And that's a surrogate.

A real escape system should have another set of equipment than that one which it spots.
For example, Apollo was using LES engines to spot the LV cruise engines. Ascent stage engine to spot the descent stage engine, and so on.

Otherwise it's not an escape system, it's a reliability improvement.

Edited August 16, 2018 by kerbiloid

[Xd the great]

I see what you mean here, but the bfs was supposed to have the same safety as a airline jet.

Airline jets dont have emergency parachutes or ejection seats as far as i know...