SpaceX 2018 Lunar Flyby

Terraformer · 2017-02-27 16:18:24

I feel this needs it's own thread.

Only a flyby, but hopefully (!) the harbinger of things to come.

Oldfart1939 · 2017-02-27 16:56:55

Bam! NASA just got a wake up call! SpaceX is a giant which is not sleeping. Will this force NASA into sending a crew around the Moon on the first SLS flight?

An update on spaceflight101 indicated the charges would be similar to a Russian Soyuz seat to the ISS. My last recollection was they charged a private individual something like $20 Million, but I've seen NASA quoting $80 Million to fly on a Soyuz. This might make 2018 one exciting year to be alive!

SpaceNut · 2017-02-27 17:01:48

To keep the topic tightly constrained we must only talk to the content in the article which will only be a space x hardware only mission unlike the other Apollo 8 redux topic.

ArticleFebruary 27, 2017
SpaceX to Send Privately Crewed Dragon Spacecraft Beyond the Moon Next Year 2018.
We are excited to announce that SpaceX has been approached to fly two private citizens on a trip around the moon late next year. They have already paid a significant deposit to do a moon mission. Like the Apollo astronauts before them, these individuals will travel into space carrying the hopes and dreams of all humankind, driven by the universal human spirit of exploration. We expect to conduct health and fitness tests, as well as begin initial training later this year. Other flight teams have also expressed strong interest and we expect more to follow. Additional information will be released about the flight teams, contingent upon their approval and confirmation of the health and fitness test results.

What we know that space x must develope is a larger service module for the Dragon and an Earth departure stage for a free return flight for mission time of about a week round trip. Anything else will require further hardware developement if spending longer periods of time and doing more science will require a habitat unit as well.

Most importantly, we would like to thank NASA, without whom this would not be possible. NASA’s Commercial Crew Program, which provided most of the funding for Dragon 2 development, is a key enabler for this mission. In addition, this will make use of the Falcon Heavy rocket, which was developed with internal SpaceX funding. Falcon Heavy is due to launch its first test flight this summer and, once successful, will be the most powerful vehicle to reach orbit after the Saturn V moon rocket. At 5 million pounds of liftoff thrust, Falcon Heavy is two-thirds the thrust of Saturn V and more than double the thrust of the next largest launch vehicle currently flying.

A nice way to say thank you....

Later this year, as part of NASA’s Commercial Crew Program, we will launch our Crew Dragon (Dragon Version 2) spacecraft to the International Space Station. This first demonstration mission will be in automatic mode, without people on board. A subsequent mission with crew is expected to fly in the second quarter of 2018. SpaceX is currently contracted to perform an average of four Dragon 2 missions to the ISS per year, three carrying cargo and one carrying crew. By also flying privately crewed missions, which NASA has encouraged, long-term costs to the government decline and more flight reliability history is gained, benefiting both government and private missions.

While we have the OMB saying that space x may have a probable delay of mission Space x has indicated that it will refocus and not let any delay happen for getting men to orbit.

Once operational Crew Dragon missions are underway for NASA, SpaceX will launch the private mission on a journey to circumnavigate the moon and return to Earth. Lift-off will be from Kennedy Space Center’s historic Pad 39A near Cape Canaveral – the same launch pad used by the Apollo program for its lunar missions. This presents an opportunity for humans to return to deep space for the first time in 45 years and they will travel faster and further into the Solar System than any before them.

Space x has done a good job of maintaining quality and effort to keep to scheduel.

Designed from the beginning to carry humans, the Dragon spacecraft already has a long flight heritage. These missions will build upon that heritage, extending it to deep space mission operations, an important milestone as we work towards our ultimate goal of transporting humans to Mars.

Why is this working is that they are only making small changes to the existing craft rather than a fresh new design as Nasa has had to do but I digress....

Back to the Space x show.....

Oldfart1939 · 2017-02-27 17:18:56

Here's the link to spaceflight101:

http://spaceflight101.com/spacex-announ … -missions/

RobertDyck · 2017-02-27 17:40:24

Great! Wonderful! Exciting! Go SpaceX! However, I must poke a hole in hyperbole.

Falcon Heavy is due to launch its first test flight this summer and, once successful, will be the most powerful vehicle to reach orbit after the Saturn V moon rocket. At 5 million pounds of liftoff thrust, Falcon Heavy is two-thirds the thrust of Saturn V and more than double the thrust of the next largest launch vehicle currently flying.

Payload mass to orbit will be roughly double that of Shuttle, however if you include mass of the Space Shuttle Orbiter itself, Shuttle was more powerful. Solid rocket boosters produced 2.8 million pounds of thrust each at liftoff. Main engines produced 393,800 pounds thrust each at liftoff. Total thrust at liftoff was 6.7814 million pounds thrust. Round that off to 6.78 million pounds.

And the Soviet Energia launched successfully twice. The first time launched the Polyus satellite. Launch succeeded but the satellite was supposed to use thrusters on the satellite to circularize orbit. Satellite thrusters fired in the wrong direction causing it to de-orbit, safely crashing in the ocean. Soviet Premier Michael Gorbachev attended the launch, discovered they were launching Polyus. He hadn't authorized Polyus, so there's high probability the satellite was deliberately destructed. You could argue the satellite did not complete one full orbit, but the Energia launch vehicle worked perfectly. The second launch of Energia was the Buran space shuttle orbiter, launched as an unmanned test of the orbiter. Everything worked perfectly. Buran did complete one full orbit of Earth before returning and landing on the runway at the Baikonur Cosmodrome. So Energia did successfully launch something into orbit. Energia could lift 88 metric tonnes to 200km orbit. Falcon Heavy was said to lift 53 metric tonnes to LEO (185km orbit), but after converting the core stage to Falcon 9 Full Thrust, the SpaceX website claims it can lift 54 metric tonnes.

So Falcon Heavy the most powerful after Saturn V? Not really. It has the most payload to LEO of any American launch vehicle, after Saturn V. You have to qualify "payload" and "American" to say that. And once SLS block 1 launches, it will be able to lift 70 metric tonnes to LEO, so it will be the second most powerful American vehicle after Saturn V.

SpaceNut · 2017-02-27 18:14:31

GW wrote:

Crewed Dragon needs a service module of about 3.4 km/s delta-vee capability to do that mission

So depending on what fuel and engines we still need to figure out power and other supplies required for a safe trip.

Excelsior · 2017-02-27 21:16:18

Hopefully this is just a first step to an affordable Lunar Program using commercial hardware... this from before the announcement.

How to Get Back to the Moon in 4 Years--This Time to Stay

According to the Washington Post, Donald Trump wants to make a splash in space. And he apparently wants to make that splash by orbiting the Moon.
Orbiting the Moon? Merely circling it? What a comedown from America’s past high…landing twelve humans on the lunar surface. But there is a way to outdo America’s past achievements. And to accomplish this in a shorter time with a smaller budget than the Trump team imagines.
It’s a way to get to the Moon and to stay there permanently. A way to begin this process immediately and to achieve moon landings in less than four years.
How?
Turn to private industry. Turn to two companies in particular—Elon Musk’s SpaceX and Robert Bigelow’s Bigelow Aerospace. Why? Because the approach that NASA’s acting administrator Robert Lightfoot is pushing won’t allow a Moon landing....

SpaceNut · 2017-02-27 21:28:24

One can only hope that other rich people will keep buying seats to not only circle the moon but to possibly land on it as well. That and an increase level or requests by space agencies for the same will not only drive price but also science and colonization of space its self.
Space x has the Raptor engine for methane useage for a future ship design but do they have enough time integrate it into the EDS or into a lander for moon missions in such a short time.

Excelsior · 2017-02-27 21:45:03

SpaceNut wrote:

One can only hope that other rich people will keep buying seats to not only circle the moon but to possibly land on it as well. That and an increase level or requests by space agencies for the same will not only drive price but also science and colonization of space its self.
Space x has the Raptor engine for methane useage for a future ship design but do they have enough time integrate it into the EDS or into a lander for moon missions in such a short time.

A Dragon 2 uses but a fraction of the Falcon Heavy's capacity, could the 2nd stage not handle the ED burn?

SpaceNut · 2017-02-27 22:01:26

That is the problem with current design is that it can just circularize orbit So a new design would be required to fit under the total lift payload of 53mT minus the current capsule design with supplies and people which will have a mass somewhere around 10 mt plus. So even that will not be all fuel as the structure to make the extended stage will also cut into the allotment of fuel to create the push that we need.

Excelsior · 2017-02-27 22:25:05

SpaceNut wrote:

That is the problem with current design is that it can just circularize orbit So a new design would be required to fit under the total lift payload of 53mT minus the current capsule design with supplies and people which will have a mass somewhere around 10 mt plus. So even that will not be all fuel as the structure to make the extended stage will also cut into the allotment of fuel to create the push that we need.

I don't think they would have made the announcement if there was a long list new equipment to develop. Maybe the Raptor is farther along than they let on.

SpaceNut · 2017-02-27 23:13:08

https://en.wikipedia.org/wiki/Raptor_(r … ne_family)

The engines are specifically intended to power both high-performance lower and upper stages of the Interplanetary Transport System launch vehicle. First test firing of a Raptor development engine on September 25, 2016 in McGregor, Texas.

Design for an all new ship changing from Lox Kerosene to Lox Methane stages....

Oldfart1939 · 2017-02-27 23:16:46

The September 25, 2016 test was conducted using a 1/3 scale Raptor engine, but it still outperformed the current Merlin D.

Terraformer · 2017-02-28 05:56:10

If they're just doing a flyby, could a direct launch on Falcon Heavy work? The launch abort system should be able to work with FH as well as F9, if the acceleration is the same, so it shouldn't need much to man-rate it - after all, it *is* just a large F9 rocket with boosters, isn't it?

There should be enough payload capacity to do it, and the Dragon is designed for direct re-entry from Luna or Mars. Perhaps they'll be developing a pressurised trunk as a habitable module? Otherwise it would be very cramped, even if it is less cramped than the Apollo command module...

Last edited by Terraformer (2017-02-28 05:57:02)

GW Johnson · 2017-02-28 11:06:04

My delta-vee estimates, crude as they are, show direct surface launch from Earth to Mars transfer by min-energy Hohmann trajectory is about a 12.1 km/s requirement. More if you use a faster trajectory, as most do today.

Spacex lists on their site that a Falcon-Heavy flown fully-expendably can send 13.6 metric tons to Mars. It does NOT say by which trajectory, but if the payload is unmanned, the slower Hohmann trajectory should not be objectionable. I'm estimating a fully-loaded crew Dragon at a smidge over 11 metric tons, with something like 0.8 km/s delta vee in its Super Draco system.

I also show a direct surface launch to lunar orbit (including the circularization burn) to be 12.4 km/s. That is almost the same. Lighten the crewed Dragon a bit, and Falcon-Heavy should be able to put a crewed Dragon into lunar orbit, using the second stage for the circularization burn.

Now if the crewed Dragon is closer to 9 tons than 11, its delta-vee capability should be closer to 0.9 or even 1 km/s. That's enough to leave lunar orbit to come home (0.8 needed). It means no propulsive landing, you use chutes and must be picked up at sea (more expensive). But it looks to me like a lightened crewed Dragon on a Falcon Heavy might just barely be able to reprise the Apollo-8 lunar orbit mission.

Looking ahead, if you send a lander to lunar orbit on another rocket ahead of the crewed Dragon shot, then you could start thinking about reprising Apollo-11. And you could start thinking about shooting stuff to the lunar surface to support doing more than just reprise Apollo, all without expensive SLS/Orion. A one-way landing on the moon direct from the surface of the Earth requires 14 km/s.

Somebody really needs to be working on one-way and two-way landers for the moon. Big enough for men or cargo, but small enough to fit Falcon-Heavy.

GW

Last edited by GW Johnson (2017-02-28 11:11:50)

Oldfart1939 · 2017-02-28 11:37:24

I was just looking at my copy of The Case for Mars, and on p.96 there's a small table of delta V'ees for various Hohmann transfer trajectories to Mars with free return.

Here's some information for departure from LEO. For ascent to LEO, the delta V is around 8.7 km/sec.

delta V (kM/s) Transit to Mars (days) Mars Aeroentry

3.34 250 Easy

5.08 180 Acceptable

6.93 140 Dangerous

For the around the Moon flight, it seems that the Falcon 9 second stage has enough to send the Dragon + pressurized trunk + some extra fuel to circumnavigate the Moon on a free return trajectory.

Terraformer · 2017-02-28 11:41:06

I don't think they're planning on an orbit, at least to start. Probably a free return mission. I don't know what the delta-V requirement for that is.

If an expendable Falcon Heavy (FH) could just about pull off an orbital mission, two reusable ones - one launching a propulsion module for trans-Lunar injection (TLI), the other a modified Dragon with sufficient delta-V for Lunar orbit insertion and trans-Terran injection - should be able to. Perhaps they could do that in 2019...

GW Johnson · 2017-02-28 11:53:45

When I first started looking at this, I didn't think Falcon-Heavy/crew Dragon could enter lunar orbit and get back out to come home. Now I think it just might be possible, if they fly with a small crew and just enough supplies for about 10 days max. That's the stock crew Dragon with the existing unpressurized trunk. Which means they could go fly with what they already have, as soon as Falcon-Heavy starts flying.

That's restricted to chute landings in the ocean, because the worst case delta-vee to come home is 0.8 km/s from lunar orbit, and the crewed Dragon could just barely do that with its Super Dracos if not at max weight, and still have some propellant for attitude control and a course correction on the way home. It has to do all that with the trunk, which is where the solar electricity comes from. They shed the trunk right before reentry.

The Falcon-Heavy second stage gets left in lunar orbit, or if not totally out of fuel, crashed on the moon. Its LOX cannot boil away in about 4 days trip time to the moon, and its kerosene cannot be allowed to freeze in that time, if the lunar orbit entry burn is to be made with that stage. That's probably the biggest risk, as the stage has no provisions that I know of for longer-term thermal control, and the LOX tank is not a dewar.

I'm hazarding the guess this is what they eventually have in mind. It's not real clear whether next year's planned shot is just a swing-by free return trajectory, or a lunar orbit shot. We'll see. But my point is that there is potential for lunar orbit missions.

GW

louis · 2017-02-28 15:18:10

I've been banging the drum for lunar tourism for a number of years here. I think it's very doable and there is a market worth billions of dollars among the planet's super-rich. I think Musk has spotted the potential to generated huge revenue and fund his Mars project.

Oldfart1939 · 2017-02-28 18:14:49

Louis-

In a way, this isn't that different than the early days of aviation. The super rich in the days just after the Wrights first flew were slinging money around for airplane rides, and posting huge (for the times) cash prizes for specific accomplishments. There were prizes posted for the first flight coast to coast in the U.S. Another significant one was for the first crossing of the English Channel. The names are legend in aviation history. The Bendix Trophy, The Collier Trophy, etc. I was reading that these 2 guys are paying Musk about the same as the Russians are charging for civilian seats on their Soyuz up to the ISS, which last I read was $22 Million each. If they are charged what the NASA astronauts have to pay, that's $80 Million per each.

SpaceNut · 2017-02-28 21:11:12

The Delta IV heavy has flown but Space x has not flown its version yet as they will need to develope the attachment coupling hardware, seperation bolts for it to work and new flight programming to keep the boosters from creaming into each other and a larger upper stage just to be able to get to the much larger 53mT payload.

Which brings me back to the numbers games for payload and what is called payload.....Payload to me is a measure of what is still joined together and not just a cargo total as it really does include the mass of the other parts which are still being said to be the payload at that point....

louis · 2017-03-01 07:29:46

Billionaires and multi-millionaires will pay a lot for prestige - as we see with their competitive yachts. Being able to sit at a dining table and talk about your trip to the Moon will give you an unassailable prestige advantage. Once Space X can offer trips to the Moon incorporating visits to the Apollo sites, well - then lunar tourism will really take off.

Oldfart1939 wrote:

Louis-
In a way, this isn't that different than the early days of aviation. The super rich in the days just after the Wrights first flew were slinging money around for airplane rides, and posting huge (for the times) cash prizes for specific accomplishments. There were prizes posted for the first flight coast to coast in the U.S. Another significant one was for the first crossing of the English Channel. The names are legend in aviation history. The Bendix Trophy, The Collier Trophy, etc. I was reading that these 2 guys are paying Musk about the same as the Russians are charging for civilian seats on their Soyuz up to the ISS, which last I read was $22 Million each. If they are charged what the NASA astronauts have to pay, that's $80 Million per each.

Oldfart1939 · 2017-03-01 08:14:17

Even with the undeniably hefty chunk of change these guys are going to pony up for the ride, SpaceX is underwriting the bill for quite a bit of dough. I suspect this will expend all components of the Falcon Heavy, unless the 2 booster stages are recovered. I don't think they can do it any other way than as a throwaway rocket mission.

Void · 2017-03-01 13:31:34

I am wondering about eventually a landing process as partially "Space Tourism", but also as geological prospecting.

I will explain shortly....

I am unable to copy from the site at this time. I guess I am following on the most recent comment of Louis.

Granted, SpaceX itself might not be interested, as their focus is on Mars. Tourist lunar fly-by activity tests equipment and pays some of the way with tourists, so, I would be surprised if SpaceX choose to take on a diversion to the Moons surface themselves.

I am thinking that if some other entity were to manufacture a substitute for the Apollo LEM. Very stripped down.

If SpaceX can swing around the Moon, then perhaps with some type of extra fuel tank, later they could attain orbit and also return to Earth.

So, I would presume that to save time and consumables they would use Hohmann transfer method?

But I am thinking that the stripped down LEM would be put into Orbit ahead of them, using a more time consuming but fuel efficient Ballistic Capture method?
https://en.wikipedia.org/wiki/Low-energy_transfer

So, their tasks would be to achieve Lunar orbit, and then rendezvous, and then landing, assent, rendezvous, and return to Earth.

I am thinking of very brief visits to the surface, where the tourist/worker, would take some selfies, and grab some rock, but not stay on the surface very long. I think this could fit into the psychology of the kind of person who climbs Mt. Everest.

It would be risky, but so is mountain climbing, and several other things that private individuals do. Frankly to a degree, the risk gives the tourist/explorer/scientist/worker some bragging rights.

I am thinking a one passenger LEM, because unlike in the days of Apollo, computers are sufficient by now to be the main pilot.

I am thinking no cabin with life support, as the visitor would stay no more than a few hours (Provided they don't die).

There could be extra consumables on the LEM, connected to a space suited person.

There could be more than one of these light weight LEM's in orbit with the main ship. Perhaps there would be two crew, and they both want to land separately. With that some ability to rescue a stranded person might exist, since the LEMS would be robot piloted.

Since this would likely be a private space program perhaps the use of something other than a balloon suit would be allowed.

To pay for it, I am supposing that sponsors might exist who would like to obtain rock/ore samples from the activity.

That's about it.

Last edited by Void (2017-03-01 13:53:04)

GW Johnson · 2017-03-02 11:58:16

Getting to the moon is a three body problem that cannot be precisely solved by pencil-and-paper methods. In an approximate sense, you do a Hohmann transfer ellipse centered on the Earth from LEO altititude to the orbit of the moon. You plan your apogee to be about a lunar diameter or less ahead of the moon, so that it will run into you from behind. Its speed about the Earth is close to 1 km/s, while your apogee velocity relative to the Earth is only about 0.1 km/s.

The best way to capture into lunar orbit is conceptually a burn in the retrograde direction on the Earthward side of the moon that increases your velocity RELATIVE TO THE MOON up to its low orbit speed (around 0.7 km/sec). Your orbit about the moon is thus retrograde in direction. When they do this same approach on the computer, they get that figure-eight "patched conic" trajectory, and just about that same delta vee for the orbit insertion burn. The burn for a posigrade orbit direction is more than 3 times that delta vee.

The same sort of retrograde-orbit approach works for all the planets outward of Earth, where your aphelion velocity is lower than your target's orbital velocity. That also reduces entry velocity for direct landings. Inward of Earth, you have to do a catch-up burn into a posigrade orbit (or direct landing). This is because your perihelion velocity is greater than your target's orbital velocity.

This picture gets even more complicated when you try instead to capture directly into orbit about (or land directly upon) moons of planets outward of Earth. The delta-vee is generally lower if you capture into a retrograde orbit about such moons (or land directly upon them), but it is still quite high because of the orbital speed of these moons about their planets. This is particularly difficult at Jupiter.

From about Jupiter outward, Hohmann transfer is just too slow to be practical. Travel times are in decades. It's just half the period of your transfer ellipse. That's about 30-some years to Neptune (about the same to Pluto at this time in history).

The difference between your aphelion velocity (relative to the sun) and your target's orbital velocity (also relative to the sun) is your effective "velocity at infinity" for the two-body problem relative to your target. That has to be combined with its escape velocity to determine your speed relative to your target as you fall closer to it. Those do not add arithmetically, as the vectors rarely if ever line up. But you can combine them as kinetic energies in squared form Vloc = (Vinf^2 + Vesc^2)^0.5. That's how you estimate landing delta-vee, atmospheric entry delta vee, and differenced with circular orbit velocity, the delta vee into orbit.

Again, this is approximate; you do 3+ body modeling on the computer to get this "right".

GW

Last edited by GW Johnson (2017-03-02 12:10:28)

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SpaceX 2018 Lunar Flyby

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