Space X - Ryan McDonald's take

louis · 2017-10-24 14:11:03

Ryan MacDonald is always a clear, concise and perceptive presenter. I found this video very helpful:

https://www.youtube.com/watch?v=6d6TA8xcdA8

Most surprising, he suggests that Space X think they can get the cost of launching the BFR down to $60 per kg. The launch cost from Mars should be even less, I would think.

Time to rethink the economics of Mars exports? If the cost of export is $50 per kg, all sorts of luxury goods like Mars wine become a possiblity.

He covers Lockheed's misconceived plans and also Mars One - the latter is a clear dud, probably not worth further consideration.

Last edited by louis (2017-10-24 14:12:08)

RobertDyck · 2017-10-24 17:13:18

He emphasizes some points in Lockheed-Martin's proposed mission architecture. The first mission wouldn't even land crew on Mars. That's a colossal waste of money. One justification is to scout an appropriate landing location. I keep saying that was a valid argument in 1990, but that was 27 years ago. NASA chose to "prepare" with robotic missions to Mars: MGS, Odyssey, MRO, Pathfinder/Sojourner, Phoenix, MER (Spirit/Opportunity), MSL (Curiosity), MAVEN, InSight; as well as failed missions: Mars Observer, Polar Lander, Climate Orbiter. And international missions: Mars Express, Beagle 2 (failed), ExoMars 2016, ExoMars Rover, Nozomi (failed). If we start over then all the years and money is wasted.

SpaceNut · 2017-10-24 17:24:07

I agree that you already can pick a site even if its not the most perfect for a first time landing so lets get over the fear of not coming back....
Also if Space X BFR does get to that low of a number that surely shames Nasa with its SLS billion dollar workfare program.....

Quick Nasa change the first stage SLS to a landing reuseable and start to drive the cost down.....

RobertDyck · 2017-10-24 17:58:21

NASA? Resuable? Good luck with that. General Graham convinced Vice President Dan Quayle to fund DC-X. After successfully demonstrating a reusable rocket that could land on it's tail, they handed it over to NASA. They upgraded it to DC-XA, destroyed on its third flight. It was never rebuilt. I don't see NASA doing a reusable rocket any time soon.

More importantly, corporate executives for major contractors (Lockheed-Martin, Boeing) don't want anything cost effective. They want to maximize profit by gouging NASA for all they can.

louis · 2017-10-25 00:44:20

Sadly, I think you're right Robert. They just see that huge lump of money - the nearly $20 billion - and think "we'll have some of that" rather than looking at it from the task end of the telescope (which defined the heroic Apollo period).

I used to argue that NASA should be broken up into a Mars and Lunar Development Agency (to focus on colonisation or development of Moon and Mars) and a Space Science Agency (to pursue more general space objectives, and exploration of the wider solar system). Now I am not even sure it matters any more - a new NASA getting involved in Mars settlement might just be a brake and an annoyance.

RobertDyck wrote:

NASA? Resuable? Good luck with that. General Graham convinced Vice President Dan Quayle to fund DC-X. After successfully demonstrating a reusable rocket that could land on it's tail, they handed it over to NASA. They upgraded it to DC-XA, destroyed on its third flight. It was never rebuilt. I don't see NASA doing a reusable rocket any time soon.
More importantly, corporate executives for major contractors (Lockheed-Martin, Boeing) don't want anything cost effective. They want to maximize profit by gouging NASA for all they can.

Last edited by louis (2017-10-25 10:26:21)

louis · 2017-10-25 01:17:45

Not landing a crew permanently also means they must be in zero G for nearly the whole of the two years plus having to make several adjustments between zero G and Mars gravity...if anything was designed to induce ill health that must surely be it!

Another point from Ryan's video - he said the Space X BFR or BFS would get to Mars in three months...I may have missed that before. If true, three months will really help mitigate the negative effects of zero G compared with the 6-8 months I was assuming up till now.

RobertDyck wrote:

He emphasizes some points in Lockheed-Martin's proposed mission architecture. The first mission wouldn't even land crew on Mars. That's a colossal waste of money. One justification is to scout an appropriate landing location. I keep saying that was a valid argument in 1990, but that was 27 years ago. NASA chose to "prepare" with robotic missions to Mars: MGS, Odyssey, MRO, Pathfinder/Sojourner, Phoenix, MER (Spirit/Opportunity), MSL (Curiosity), MAVEN, InSight; as well as failed missions: Mars Observer, Polar Lander, Climate Orbiter. And international missions: Mars Express, Beagle 2 (failed), ExoMars 2016, ExoMars Rover, Nozomi (failed). If we start over then all the years and money is wasted.

Oldfart1939 · 2017-10-25 09:25:05

If what Ryan said is true, then Musk must be planning on a higher energy trajectory at much higher delta V from Earth. Then needs to do some retropropulsion upon approaching Mars? I agree with Louis about no provision for mitigation of zero gee transits. Microgravity disease seems to be consistently overlooked by these so-called "planners." In reality, they are planning to go nowhere. Just run the workfare system until it runs out of money.

Last edited by Oldfart1939 (2017-10-25 09:52:15)

GW Johnson · 2017-10-25 11:19:08

The 7.5 km/s entry velocity in Ryan McDonald's video confirms the higher energy trajectory with shorter flight time.

I did a crude reverse-engineering of the ITS second stage's delta-vee capabilities posted over at "exrocketman". It confirms that there is more delta-vee available, even at 150 tons delivery, than is needed to go min-energy from Earth orbit to direct entry at Mars. So I confirm the higher-energy trajectory, as well.

If somebody has real weight statement data for the first stage BFR, I can do something similar for it. As I understand it, it now uses 33 of the sea level Raptor engines.

Bob Clark is doing studies over at his site of the ITS/tanker as a possible SSTO. Like all SSTO's, payload capacity relative to ignition weight is reduced. If that is what makes reusability possible, then that is a path to launch cost reduction. But, if as a two-stage vehicle both stages are already reusable (and the BFR/ITS will be), then why not just carry the bigger payload for a similar lower cost? I think you gain more payload tons than you lose in costs flying two reusable vehicles instead of one.

I noted with interest that Ryan in his video sees pluses and minuses to the Lockheed Mars plan. They look at a one stage reusable lander, just as I did in my Mars 2016 idea posted over at "exrocketman". They also have the abort-to-orbit safety feature. The difference is, I use the extra landers for a surface rescue capability. And I send enough propellant (using electrics to avoid a lot of costs) to visit multiple sites while still providing surface rescue capability. Most of my costs savings come from not using SLS. The rest comes from lighter but larger habitat modules from Bigelow, and a lighter crew return capsule in Dragon.

Something like my mission provides the surface pathfinder that identifies "for sure" the best site for Musk to do his BFR/ITS thing. So Ryan's idea of keeping multiple architectures on the table is a really good one.

GW

Last edited by GW Johnson (2017-10-25 11:23:34)

louis · 2017-10-25 16:07:52

Good to have your confirmation on the shorter flight time. I think that is quite a game changer, bringing Mars much more within reach of the academic community who will go there to undertake research, and my analysis suggests that will be the really big economic motor in the first few decades.

For me, Musk has really thought this through and ended up with a great model of how to transplant human civilisation to Mars. I still have reservations about his colonisation scheme but in terms of providing a walkable bridge from Earth to Mars and back again, I think he has the right design.

That said, I have always wanted to see lots of creative ideas on Mars transit and colonisation battling it out.

GW Johnson wrote:

The 7.5 km/s entry velocity in Ryan McDonald's video confirms the higher energy trajectory with shorter flight time.
I did a crude reverse-engineering of the ITS second stage's delta-vee capabilities posted over at "exrocketman". It confirms that there is more delta-vee available, even at 150 tons delivery, than is needed to go min-energy from Earth orbit to direct entry at Mars. So I confirm the higher-energy trajectory, as well.
If somebody has real weight statement data for the first stage BFR, I can do something similar for it. As I understand it, it now uses 33 of the sea level Raptor engines.
Bob Clark is doing studies over at his site of the ITS/tanker as a possible SSTO. Like all SSTO's, payload capacity relative to ignition weight is reduced. If that is what makes reusability possible, then that is a path to launch cost reduction. But, if as a two-stage vehicle both stages are already reusable (and the BFR/ITS will be), then why not just carry the bigger payload for a similar lower cost? I think you gain more payload tons than you lose in costs flying two reusable vehicles instead of one.
I noted with interest that Ryan in his video sees pluses and minuses to the Lockheed Mars plan. They look at a one stage reusable lander, just as I did in my Mars 2016 idea posted over at "exrocketman". They also have the abort-to-orbit safety feature. The difference is, I use the extra landers for a surface rescue capability. And I send enough propellant (using electrics to avoid a lot of costs) to visit multiple sites while still providing surface rescue capability. Most of my costs savings come from not using SLS. The rest comes from lighter but larger habitat modules from Bigelow, and a lighter crew return capsule in Dragon.
Something like my mission provides the surface pathfinder that identifies "for sure" the best site for Musk to do his BFR/ITS thing. So Ryan's idea of keeping multiple architectures on the table is a really good one.
GW

SpaceNut · 2017-10-29 20:31:57

DaoHZ9HSiXHjGovAqLdP-8ZBbZcmSqBW3UBm4c7fkZc.png?w=922&s=f775e8711a1d567b5453cf8c38b35613

BFR is 2nd from the right in the image with the ITS being the right most...

post 1 Estimating the cost of BFR

Elon Musk announced aspirational goals for an Interplanetary Transport System (ITS) of a $200-million ship, a $130-million tanker and a $230-million booster that could cut the cost per ton to Mars eventually to less than $140,000

Slide 41 of document:
https://web.archive.org/web/20160928040 … tation.pdf

The new configuration of the booster has decreased the diameter from 12 meters to 9 and the number of engines from 42 to 31.

The dry mass for the ship has dropped from 150 to 85 metric tons, but is still anticipated as being able to carry 100 people to Mars in comfort.

Antius · 2017-10-29 23:55:58

louis wrote:

Ryan MacDonald is always a clear, concise and perceptive presenter. I found this video very helpful:
https://www.youtube.com/watch?v=6d6TA8xcdA8
Most surprising, he suggests that Space X think they can get the cost of launching the BFR down to $60 per kg. The launch cost from Mars should be even less, I would think.
Time to rethink the economics of Mars exports? If the cost of export is $50 per kg, all sorts of luxury goods like Mars wine become a possiblity.
He covers Lockheed's misconceived plans and also Mars One - the latter is a clear dud, probably not worth further consideration.

The gravity is substantially lower, so the vehicle launched from Mars would not require a lower stage and can avoid the operation cost associated with that. And the vehicle must return to Earth anyway is it is part of a reusable transport system.

But $60/kg is optimistic in either direction. These are low launch costs even to Earth orbit and assume that the launcher can follow an aircraft business model. Using the BFR as part of an interplanetary transport system, ties it up for over 2 years for each round trip.

Lets say it can shift 150t of cargo in either direction, costs $200m and carries out 10 round trips in it's lifetime. That is 1500t in each direction. For a vehicle with upfront cost of $200m, that is $66/kg. But that ignores a realistic discount rate and all other operating costs. If you want a realistic estimate, you must factor these in as well. At a guess, I would say you could double or triple this estimate to account for those costs. But you don't need to guess. You can work it out.

Why the hell would anyone be producing wine on Mars? It would be easier to grow it in the high arctic than it would on Mars. Shipping it back to Earth is just plain silly. On Earth, new world wines have put a dent in the European wine market because they can produce a product of the same quality at lower cost. Neither assumption is reasonably applicable to Mars. In fact it is difficult to conceive of any product that can be made there and exported to Earth at a comparative advantage.

Exporting to Earth orbit may be a different story. That is one comparative advantage that Mars does have. But it is weak, because we must ship the equipment to Mars first.

Oldfart1939 · 2017-10-30 09:17:07

I don't see any evidence for $66 per kilogram; the Musk statement was $140,000 per tonne. That translates, on a metric tonne basis, to $140 per kilogram, which strikes me as a more realistic figure.

What to do with the BFRs between Hohmann Transfer window was adequately stated by Elon as providing on-Earth point to point transportation. My guess is that FedEx could become a major customer for same day delivery worldwide services.

GW Johnson · 2017-10-30 11:39:05

I don't believe there is both a smaller and a larger Spacex Mars rocket design. Showing two in the illustration above is incorrect. What Musk presented at Guadalajara and then in Australia are one single still-evolving design concept. It has shrunk.

The term "BFR" seems more properly to refer to the first stage booster for the two stage design needed to reach LEO. I've seen "BFS" as a term referring to the second stage spaceship. Although, I think the term "ITR" is also referring to that same second stage spaceship. Eventually, I think a new term will come to describe the tanker form of that second stage. Maybe "BFT"?

I don't yet believe anybody's cost figures. No one should, not until the hardware starts flying. (Same applies to SLS, by the way.) But, it is clear that price to orbit (and price to Mars) is going to drop dramatically with a rocket system this big. There is an economy of scale. Flown as expendables, Falcon-9 is near $2400/pound ($5.3M/m.ton), and Falcon Heavy probably near $1000/pound ($0.45M/m.ton).

These figures might be a bit lower, or else about the same, probably only factor 2 better, flown with reduced payload reusably. That trend says BFR/ITS should only be a very few hundred $/pound to LEO. Pounds, kilograms, not much distinction at this stage, since they only differ by a factor of 2.205.

NASA thinks SLS will fly for ~$500M per launch, with block 1 payload to LEO 70 metric tons. NASA's critics think that launch price will be ~$1-2B, some 2 to 4 times higher. That's at least $7.1M/m.ton ($3200/pound), and maybe factor 2 to 4 times higher than that.

As for shuttle, its launch price was right around $1B. It could deliver up to 25 m.tons to LEO, although only about 15 tons to ISS. That's $40M/m.ton ($18,000/lb) to LEO and $67M/m.ton ($30,000/lb) to ISS. SLS is at least a little cheaper than shuttle to LEO, and maybe a lot cheaper if NASA is to be believed. But nowhere near as good as Falcon-9 is right now, much less Falcon-Heavy or BFR/ITS.

That and restrictions on importing engines from hostile Russia are why ULA is scrambling to build a new bigger launcher called Vulcan, using Bezos's new big engine, and perhaps trying to recover engines mid-air with a helicopter. Or so it is believed.

GW

Last edited by GW Johnson (2017-10-30 11:42:02)

Oldfart1939 · 2017-10-30 16:24:37

I somehow don't believe that the SLS will EVER get down to $500 million per launch, not under the present cost-plus accounting system in place for Boeing, Lockheed-Martin, and the ULA. And especially if the standing army of launch support personnel are factored into the equation. Maybe this SLS system is "good" for the states where it's being built economically, but as a single use throwaway, an colossal waste of taxpayer dollars. It's being built as a feel-good workfare program, hoping to "salvage" something from the ill fated Constellation program. I'm a space enthusiast, not a financial moron.

Oldfart1939 · 2017-10-30 16:29:41

Shifting gears here to the Falcon systems versus the BFR. In just a single year, we've seen Musk announce a significant shrinkage of the size of the BFR/ITS vehicle. I'm willing to guess that another shrink job could happen--one down to the size of the Falcon X. Elon is not stupid and will come to the realization that he's simply growing the system too big and too fast for the development timeline he's stated.

Terraformer · 2017-10-31 04:59:39

What's the largest single piece that needs to be launched for the missions he wants to do? He's planning on refuelling in orbit, so the spacecraft can launch empty. We can dock modules together. If we wanted to, we could outfit the spacecraft on orbit, reducing launch weight even further. Consumables can be launched separately.

elderflower · 2017-10-31 06:11:29

The answer to your question has to be tanks of fuel and oxidiser, Terraformer.

Terraformer · 2017-10-31 07:47:50

Not really. If you need 500 tonnes of propellent, it doesn't have to be launched all in one go. It could be launched in 1 tonne chunks, even.

I would guess the smallest minimum piece will be a basic hull - pressure vessels are going to be the biggest things we need to launch. Maybe with the fuel tanks and rockets already plumbed in. Once on orbit, internal fittings can be done, the tanks fuelled up, and provisions loaded. So the big question isn't payload so much as fairing size.

SpaceNut · 2017-11-01 18:03:18

One thing I am not seeing is any sort of docking capability for the ITS or BFR and that would class it as just a round trip cruise vehicle capable of landing on the surface of the moon or mars with selective refueling in orbit and on either surface.

3015 · 2017-11-01 22:34:40

The SpaceX BFR presentation had a slide with the ship docked with the ISS, I think they must intend for at least some versions of the BFR ship to have docking capability.

louis · 2017-11-02 06:59:35

Yes. That's my understanding.

I think there are some concerns about allowing such a big mass as the BFR ship close to the ISS. They may need to convince NASA and the other ISS partners it's safe and that might be a problem longer term. However, my view is that there is huge profit to be had from orbital and lunar tourism, so I don't see that as a deal breaker in terms of developing the BFR.

3015 wrote:

The SpaceX BFR presentation had a slide with the ship docked with the ISS, I think they must intend for at least some versions of the BFR ship to have docking capability.

Last edited by louis (2017-11-02 06:59:48)

Oldfart1939 · 2017-11-02 09:08:48

I've seen subsequent illustrations of the tanker and deep space vessel aligned tail to tail. Has anyone else seen that version? I believe that was how Musk now envisions the transfer of fuel & oxidizer to take place.

GW Johnson · 2017-11-02 10:39:46

I saw the tail-to-tail transfer illustration, too. What surprised me was the accompanying statement that the transfer is by the inertial reaction to a thruster pushing on one end of the docked pair!

That approach modifies your orbit while transferring propellant, which opens all sorts of cans of worms. The next thing that comes to mind is pumps, but they may be trying to avoid the machinery and power source weight.

The other thing that could very easily drive propellant transfer without upsetting the orbit is slightly-differential tank pressure from one vehicle to the other. So simple they may not have even thought of it.

The tanks must have some relatively-low pressure level to prevent boiling, and to help stop suction vortices of the bathtub drain type from forming during engine burn.

If these vehicles are to fly lifting entries at Earth and Mars, those tanks must be "already strong enough" to deal with a low pressure differential ship-to-ship safely.

GW

PS -- I see in today's AIAA "Daily Launch" newsletter that Spacex anticipates test-firing its Falcon-Heavy engines mid-December, and hopes to launch the thing about Dec 29. I'm guessing they finally got pad 40 back in operation. That lack of a second pad has been the real delay factor this year.

Last edited by GW Johnson (2017-11-02 10:47:25)

Oldfart1939 · 2017-11-03 11:46:48

I agree with GW re: launch pad availability being the delay factor in the Falcon Heavy program. With the impressive launch manifest/backlog of satellites, it would have been irresponsible to have another explosion putting SpaceX out of operation for a considerable time.

SpaceNut · 2017-11-03 20:11:14

The "Lockheed's misconceived plans" are little more than go big but english translation means soak Nasa for all you can get. While Mars One is one of go as far as you can with what you can just to prove you can get there.

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#1 2017-10-24 14:11:03

Space X - Ryan McDonald's take

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