SpaceX and cis-lunar Space Tourism

[Space Ghost 1962]

On abort the fins are BEHIND you on a SEPARATE VEHICLE. Not coupled.

As per the pad abort test plan, the trunk (and its fins) stays attached to Dragon during the abort, and is only separated after a safe distance from the vehicle is achieved and the drogue parachutes are deployed.

Yup, right there in the plan. Mea culpa. In that way they'd work as tail fins. And the trunk would buffer the Dragon above the separation plane.

Which is not what I remembered from an earlier presentation.  I guess the first stage destruction has more energetic debris pattern than thought before, and the hypersonic stability of the SD's in stream is much more in doubt. Originally there wasn't even going to be a trunk on crewed Dragon.

End of discussion of "fins".
Keeping the trunk attached also creates a negative pressure zone behind the Dragon. Perhaps that helps by being able to gain distance before the flow separation. A kind of hypersonic shadow.

[llanitedave]

What's the thrust to weight ratio of the Super Dracos carrying the Dragon plus trunk as opposed to the Dragon alone?

[Space Ghost 1962]

What's the maximum manifested weight of trunk contents? Or do you mean trunk weight only?

[docmordrid]

The DragonFly EIS quotes a vehicle mass of 7 tonnes with an integrated trunk. Pick your thrust number and have at it.

[moralec]

Let's try to see this from a more sustainable perspective. If you want to have tourists going to the moon and back on a regular basis, while maximizing safety and minimizing costs, it doesn't make sense to think about a single Apollo-like system around the Drago capsule, handling both the transportation from earth to the moon and the landings. Carrying a Dragon capsule with a heat shield all the way to the moon for example, is unnecessary. You could have instead several specialized pieces of infrastructure (one of them being the Dragon spacecraft), each handling a different part of the trip. For example :

- the reusable dragon v2 could be used to take costumers from the earth to LOE, and back. This spacecraft was designed and its optimized for this. It does not need to be larger as it currently is, as this would be a shirt trip.
- A new large permanent vessel (a space cruise), with several modules, would be the ideal way of taking the tourists from LOE to moon orbit. It would make sense to build this in LEO. Spacex could preform several FH launches to take all the necessary parts. The use of light materials seems attractive, but is important to take into account that materials to minimize radiation exposure are required. A ship like this  could be powered with ion thrusters, or with a liquid fuel burner.  You could use unmanned dragon ships to supply it with food, water and other consumables while it is on LEO. A permanent life support like the one on the IIS could be included here, as this vessel should be used on a permanent basis.
- A lunar lander could be included in the setup in order to do the lunar excursions. Landing a large ship in the moon is unnecessary. A smaller one like the one used on the Apollo program is a better choice. It could be even left on lunar orbit. Is a waste of resources to bring it back and forth.

This modular system seems more appropriate for the idea of moon turism. Additionally it could be expanded with LEO, lunar orbit and lunar surface stations acting like hotels. All required supplies should be handled with pure cargo vessels as many elements do not require pressurization.

Comments?

[aero]

2001: A Space Odyssey - without the monoliths.

[groundbound]

I think we need to be awfully careful about excluding mars from the discussion.

SpaceX is a company that has mars as its central ambition. That is unlikely to change. So the success of any plans to do anything else will depend on how well it dovetails with mars-focused hardware and plans. In many cases, suboptimal schemes that more highly leverage pre-existing (and reusable) hardware and expertise.

Make lunar plans mars-agnostic, and you likely talking about some company other than SpaceX.

[AncientU]

Let's try to see this from a more sustainable perspective. If you want to have tourists going to the moon and back on a regular basis, while maximizing safety and minimizing costs, it doesn't make sense to think about a single Apollo-like system around the Drago capsule, handling both the transportation from earth to the moon and the landings. Carrying a Dragon capsule with a heat shield all the way to the moon for example, is unnecessary. You could have instead several specialized pieces of infrastructure (one of them being the Dragon spacecraft), each handling a different part of the trip. For example :

- the reusable dragon v2 could be used to take costumers from the earth to LOE, and back. This spacecraft was designed and its optimized for this. It does not need to be larger as it currently is, as this would be a shirt trip.
- A new large permanent vessel (a space cruise), with several modules, would be the ideal way of taking the tourists from LOE to moon orbit. It would make sense to build this in LEO. Spacex could preform several FH launches to take all the necessary parts. The use of light materials seems attractive, but is important to take into account that materials to minimize radiation exposure are required. A ship like this  could be powered with ion thrusters, or with a liquid fuel burner.  You could use unmanned dragon ships to supply it with food, water and other consumables while it is on LEO. A permanent life support like the one on the IIS could be included here, as this vessel should be used on a permanent basis.
- A lunar lander could be included in the setup in order to do the lunar excursions. Landing a large ship in the moon is unnecessary. A smaller one like the one used on the Apollo program is a better choice. It could be even left on lunar orbit. Is a waste of resources to bring it back and forth.

This modular system seems more appropriate for the idea of moon turism. Additionally it could be expanded with LEO, lunar orbit and lunar surface stations acting like hotels. All required supplies should be handled with pure cargo vessels as many elements do not require pressurization.

Comments?

Sustainable... infrastructure... reusable.
Sounds like what we've been missing.
Just add fuel -- in LEO for the cruise ship, and Lunar orbit for the lander.  Perhaps Meth/LOX???
Great practice for Mars!

[sanman]

Let's try to see this from a more sustainable perspective. If you want to have tourists going to the moon and back on a regular basis, while maximizing safety and minimizing costs, it doesn't make sense to think about a single Apollo-like system around the Drago capsule, handling both the transportation from earth to the moon and the landings. Carrying a Dragon capsule with a heat shield all the way to the moon for example, is unnecessary. You could have instead several specialized pieces of infrastructure (one of them being the Dragon spacecraft), each handling a different part of the trip. For example :

- the reusable dragon v2 could be used to take costumers from the earth to LOE, and back. This spacecraft was designed and its optimized for this. It does not need to be larger as it currently is, as this would be a shirt trip.
- A new large permanent vessel (a space cruise), with several modules, would be the ideal way of taking the tourists from LOE to moon orbit. It would make sense to build this in LEO. Spacex could preform several FH launches to take all the necessary parts. The use of light materials seems attractive, but is important to take into account that materials to minimize radiation exposure are required. A ship like this  could be powered with ion thrusters, or with a liquid fuel burner.  You could use unmanned dragon ships to supply it with food, water and other consumables while it is on LEO. A permanent life support like the one on the IIS could be included here, as this vessel should be used on a permanent basis.
- A lunar lander could be included in the setup in order to do the lunar excursions. Landing a large ship in the moon is unnecessary. A smaller one like the one used on the Apollo program is a better choice. It could be even left on lunar orbit. Is a waste of resources to bring it back and forth.

This modular system seems more appropriate for the idea of moon turism. Additionally it could be expanded with LEO, lunar orbit and lunar surface stations acting like hotels. All required supplies should be handled with pure cargo vessels as many elements do not require pressurization.

Comments?

Well, if you can have a Red Dragon, then you could also have a Silver Dragon. The Silver Dragon would be a custom-designed variant meant to travel back and forth between the Moon's surface and LEO/ISS. It would not have a heat shield, and could have a larger form factor comparable to Dragon+Trunk, carrying extra propellant and possibly additional cargo/crew space. It would also be equipped with the solar panels that are on the trunk of DragonV2. It would be capable of docking with ISS.

[Manabu]

To sidestep all this concern about the escape system with extra weight, what about doing this in two launches: one FH to put the BEAM and vehicle in orbit, and another F9R carrying just the Dragon with the tourist. Both dock in orbit and then proceed for the Moon.

The weight savings on FH could be directed at a bigger living module, or in making the boosters reusable, thus paying for the extra F9R launch that should be relatively cheap if all goes right with SpaceX reusability plans.

[CuddlyRocket]

SpaceX is a company that has mars as its central ambition. That is unlikely to change. So the success of any plans to do anything else will depend on how well it dovetails with mars-focused hardware and plans. In many cases, suboptimal schemes that more highly leverage pre-existing (and reusable) hardware and expertise.

Make lunar plans mars-agnostic, and you likely talking about some company other than SpaceX.

Another point to make is that SpaceX is a commercial company; it's not going to go to the Moon or set up a Lunar transportation infrastructure unless someone else is paying for it; and if that someone is also a commercial entity they're going to want to minimise capital at risk and maximise return. That suggests they're going to use either pre-existing equipment or reasonably straightforward modifications thereof; expenditure on additional equipment will have to wait until a profitable business model is established.

There's also the matter of the crew. I should imagine that the FAA or equivalent will insist on two qualified astro-pilots, and it's not common for employees to pay for their own ticket! That means there'll be even stronger pressure to maximise the number of people carried at one time. One possibility is that passengers who are qualified astro-pilots could get a discount for acting as the co-pilot. That would probably mean them paying for their own training - which could be a nice sideline for someone - and be a common career path for civilian astronauts.

As for the problem with toilet functions and lack of privacy, they might manage this in the early days by running all-male and all-female flights (though there could be a legal problem if there's a substantial imbalance and therefore employment opportunities for one gender).

[Dave G]

I should imagine that the FAA or equivalent will insist on two qualified astro-pilots...

Why?

As I understand it, the FAA is not really concerned with astronauts dying in space.  The FAA is concerned with potential accidents affecting people/property on the ground. 

In general, if you want to risk your life doing something, the government usually doesn't get in your way, they just want to be sure you don't cause any damage to others in the process.

Astronauts travel at their own risk.

[Dave G]

Carrying a Dragon capsule with a heat shield all the way to the moon for example, is unnecessary. You could have instead several specialized pieces of infrastructure (one of them being the Dragon spacecraft), each handling a different part of the trip. For example :

- the reusable dragon v2 could be used to take costumers from the earth to LEO, and back. This spacecraft was designed and its optimized for this. It does not need to be larger as it currently is, as this would be a shirt trip.

- A new large permanent vessel (a space cruise), with several modules, would be the ideal way of taking the tourists from LEO to moon orbit.

...

The same approach could be used to go to Mars.

However, the main issues are:
1) decelerating the large transfer vehicle into a Lunar or Mars orbit.
2) decelerating the large transfer vehicle back into low Earth orbit.

Aerobraking could be used for Earth and Mars orbits, but this would require some amount of heat shielding.  For the moon there's no atmosphere, so you would need to use a lot of propellant, which would add significant mass. Perhaps a nuclear thermal rocket would solve this issue.

As an alternative, an expendable hab module is relatively cheap, and a free return trajectory would not require decelerating to any orbit.  Note that the Dragon heat shield is designed for planetary return speeds.

Also, it may be possible to use the FH second stage LOX tank as a hab module.  Remember that the second stage powers TLI, so it's already on the trip to the moon.  All you would need is a hatch and some thrusters on the second stage for docking.

[AncientU]

Carrying a Dragon capsule with a heat shield all the way to the moon for example, is unnecessary. You could have instead several specialized pieces of infrastructure (one of them being the Dragon spacecraft), each handling a different part of the trip. For example :

- the reusable dragon v2 could be used to take costumers from the earth to LEO, and back. This spacecraft was designed and its optimized for this. It does not need to be larger as it currently is, as this would be a shirt trip.

- A new large permanent vessel (a space cruise), with several modules, would be the ideal way of taking the tourists from LEO to moon orbit.

...

The same approach could be used to go to Mars.

However, the main issues are:
1) decelerating the large transfer vehicle into a Lunar or Mars orbit.
2) decelerating the large transfer vehicle back into low Earth orbit.

Aerobraking could be used for Earth and Mars orbits, but this would require some amount of heat shielding.  For the moon there's no atmosphere, so you would need to use a lot of propellant, which would add significant mass. Perhaps a nuclear thermal rocket would solve this issue.

As an alternative, an expendable hab module is relatively cheap, and a free return trajectory would not require decelerating to any orbit.  Note that the Dragon heat shield is designed for planetary return speeds.

Also, it may be possible to use the FH second stage LOX tank as a hab module.  Remember that the second stage powers TLI, so it's already on the trip to the moon.  All you would need is a hatch and some thrusters on the second stage for docking.

Multiple choice(chose one):
A. Cis-lunar Space Tourism
B. Expendable

[InfraNut2]

Multiple choice(chose one):
A. Cis-lunar Space Tourism
B. Expendable

An important point presented in a fun way. I like it!   

It deserves to be repeated, and I'll do it in a less over-simplified and less fun way:

    Reuse is the key to make cis-lunar space tourism widespread instead of rare

[ChrisWilson68]

Well, if you can have a Red Dragon, then you could also have a Silver Dragon. The Silver Dragon would be a custom-designed variant meant to travel back and forth between the Moon's surface and LEO/ISS. It would not have a heat shield, and could have a larger form factor comparable to Dragon+Trunk, carrying extra propellant and possibly additional cargo/crew space. It would also be equipped with the solar panels that are on the trunk of DragonV2. It would be capable of docking with ISS.

You're missing the whole point of Red Dragon, which is that it makes only minor modification to the existing Dragon.

Your Silver Dragon is so vastly different from Dragon that you get virtually no benefit from starting with Dragon at all.  You might as well start from scratch and design a Moon lander.

[ChrisWilson68]

There's also the matter of the crew. I should imagine that the FAA or equivalent will insist on two qualified astro-pilots

I've flown as a passenger on two different commercial flights in the United States that included only one crew member, the pilot.  One was a small airline flight from Puerto Rico to the U.S. Virgin Islands and the other was a helicopter tour in Hawaii.  The FAA has no problem with only a single pilot when the number of passengers is small.

[A_M_Swallow]

{snip}
Also, it may be possible to use the FH second stage LOX tank as a hab module.  Remember that the second stage powers TLI, so it's already on the trip to the moon.  All you would need is a hatch and some thrusters on the second stage for docking.

LOX tanks are empty boxes.  You would also have to add things like a galley, toilet, air conditioning, cabinets and lights before you could live in it.  Such modifications can only be done on the Earth's surface.

[cryptoanarchy]

As for the problem with toilet functions and lack of privacy, they might manage this in the early days by running all-male and all-female flights (though there could be a legal problem if there's a substantial imbalance and therefore employment opportunities for one gender).

Or they could use a curtain.

[CuddlyRocket]

I should imagine that the FAA or equivalent will insist on two qualified astro-pilots...

Why?

As I understand it, the FAA is not really concerned with astronauts dying in space.  The FAA is concerned with potential accidents affecting people/property on the ground. 

In general, if you want to risk your life doing something, the government usually doesn't get in your way, they just want to be sure you don't cause any damage to others in the process.

Astronauts travel at their own risk.

There's a difference between employees and passengers. Also between adventurers and tourists. And between screened and trained people and anyone with the money for the ticket. There's already political pushback against the laxer safety regime envisaged for commercial crewed flights; can you imagine the press and political furore when (and it will be when) there's the first fatality? Careers have been blighted, even ended, for less and any politician and especially bureaucrat will want to ensure they have their umbrella in place when blame rains down from on high (a common simile used every week by British civil servants).

They could say 'at your own risk' for flying; but they don't.

I've flown as a passenger on two different commercial flights in the United States that included only one crew member, the pilot.  One was a small airline flight from Puerto Rico to the U.S. Virgin Islands and the other was a helicopter tour in Hawaii.  The FAA has no problem with only a single pilot when the number of passengers is small.

That's a hangover from the fact that passenger flights with single pilots were already the mainstay of the industry before it started to be regulated. In the US regulation started in 1926. Aeromarine Airways had gone out of business before that having made more than 2,000 scheduled flights and carried nearly 10,000 passengers (i.e. <5 passengers a flight on average), and that's one airline. (They were brought down by a crash with passenger fatalities.) Passenger spaceflight won't have that luxury, especially as we're constantly being told that spaceflight is much, much more dangerous than aviation.

As for the problem with toilet functions and lack of privacy, they might manage this in the early days by running all-male and all-female flights (though there could be a legal problem if there's a substantial imbalance and therefore employment opportunities for one gender).

Or they could use a curtain.

Which would stop neither sound nor smells nor the inescapable fact that everyone will know what you're doing. People can be very squeamish about such things, especially in mixed-gender company.