Exoscientist

Because of the large number of engines on the Falcon 9 and the long length of the stage it’s center of gravity is even further aft yet it is able renter broadside. Robert Clark

This report estimates the launch market as approx. $48 Billion per year by 2030: Global Space Launch Services Market is projected to reach at a market value of US$ 47.6 Billion by 2030: Visiongain Research Inc October 05, 2021 09:33 ET | Source: Visiongain Ltd https://www.globenewswire.com/news-release/2021/10/05/2308874/0/en/Global-Space-Launch-Services-Market-is-projected-to-reach-at-a-market-value-of-US-47-6-Billion-by-2030-Visiongain-Research-Inc.html At a going rate of approx. $10,000 per kilo to LEO that would amount to 4,800 tons to orbit. For a SLS lofting nearly 100 tons to orbit even in SLS 1 form, that’s quite a lot of launches it could take part in per year IF it could do it at a competitive price. If it could do 10 reuses, that could bring the price down to $400 million per flight, or $4,000 per kilo, about the price of the reusable F9 when new, or a bit more than $3,000 per kilo of the used F9. But IF it could do 20 reuses, within the capabilities of some expendable engines, it would be $2,000 per kilo which would beat even the F9 used reusable price. About the landing, there would be additional development cost for the horizontal landing thrusters. But pressure-fed thrusters are a relatively simple technology. Compare for example the time SpaceX spent developing the Draco thrusters on the Dragon to the time developing the Merlin engine. And from discussion of the thrusters on the Starship they seem more like an afterthought compared to the cost, time, and complexity put into the Raptor engines. How about giving the RS-25’s on the SLS core restart capability? Again I’ll refer to the redoubtable Henry Spencer: Newsgroups: sci.space.shuttle From: henry@spsystems.net (Henry Spencer) Subject: Re: One part Oxygen, two parts Hydrogen and BOOM! Date: Sat, 14 Oct 2000 03:37:23 GMT In article <slrn8ue2f1.bv2.zaitcev@js006.noname.ru>, Pete Zaitcev <zaitcev@yahoo.com> wrote: >> The SSMEs use "torch" igniters, little oxygen/hydrogen burners firing into >> the preburners and chambers. The igniters themselves are ignited by, >> essentially, high-tech spark plugs. > >I see... obviously there cannot be a spark in a vacuum. Not entirely true, but irrelevant -- when the igniter fires up, there's an oxygen/hydrogen gas mixture there for the spark to travel through. >Is the plug the reason engines cannot be restarted in orbit or >there is more to the story? There's nothing *fundamental* in the SSME which makes an in-space restart impossible -- no one-shot parts or anything like that -- but it's a complicated engine which has to be set up exactly right for a successful start, and ground equipment (and gravity!) helps out with that. It would not be difficult to develop a variant which could start itself in space, but there has been no reason to do that. -- Microsoft shouldn't be broken up. | Henry Spencer henry@spsystems.net It should be shut down. -- Phil Agre | (aka henry@zoo.toronto.edu) https://yarchive.net/space/shuttle/ssme_ignition.html So likely it could be done by Aerojet, but I have no confidence they could do it in an affordable manner. Or more precisely, I have no confidence they would do it at an affordable price charged to NASA. For instance the RS-25 engine used on the SLS is derived from the SSME. It was expected to be cheaper than the SSME as it it used a lower parts counts and was not required to have the 100 times reusability of the SSME. But instead Aerojet charged more for this engine than the SSME even when accounting for inflation: NASA will pay a staggering $146 million for each SLS rocket engine. The rocket needs four engines, and it is expendable. ERIC BERGER - 5/1/2020, 6:55 PM https://arstechnica.com/science/2020/05/nasa-will-pay-a-staggering-146-million-for-each-sls-rocket-engine/ About the payload lost on reusability, a stage that goes to LEO can remain in orbit for a few orbits to come back over the landing site so minimal propellant is burned to return to launch site. If we do use a large upper stage, then the SLS would not go to orbit and as SpaceX showed you would need minimal fuel burned if landed down range, and so minimal payload lost, rather than returning to launch site. However, there is then the cost of the upper stage. If it were the Ariane 5/6, the cost of the Ariane 6 being as low as $77 million, it should be even lower than that without the Ariane side boosters or upper stage. ARIANE 6 VS. SPACEX: HOW THE ROCKETS STACK UP The European Space Agency is planning to use the Ariane 6 for a variety of missions. ESA MIKE BROWN 1.24.2022 2:00 PM In January 2021, Politico reported that the Ariane 6 could launch for as little as $77 million. That’s a steep discount from the $177 million price tag for the Ariane 5. https://www.inverse.com/innovation/ariane-6-vs-spacex About the landing thrusters, I wouldn’t give a contract for it to any of the usual aerospace companies under NASA’s cost-plus contracts. Instead I would prefer doing it “in house”, so to speak. I was quite impressed by a team at Johnson Space Center led by chief NASA engineer Stephen Altemus developing an unmanned lunar lander for only $14 million development cost: The Morpheus lunar lander as a manned lander for the Moon. http://exoscientist.blogspot.com/2014/06/the-morpheus-lunar-lander-as-manned.html The approach the NASA team used on saving costs was likely analogous to that used by commercial space in cutting costs. No doubt also the pressure-fed engines being used rather than complex turbo-pump engines contributed to the low development cost. Robert Clark

The SLS is now projected to cost $4 .1 billion per flight. Because of that severe cost it is projected to only fly once per year. This can not form the basis of a sustainable Moon colonization plan. But suppose we could make the SLS reusable? It’s already known the side boosters can be made reusable as with the shuttle program. The engines on the SLS core stage were derived from the shuttle engines which were intended to be reused up to 100 times. However, since the SLS was intended to be expendable the shuttle-derived engines on the core were designed cheaper to be expendable. However, any rocket engine even an expendable in reality is reusable at least 10 times or more. This is because they have to be certified for several firings for testing purposes. This is described by the well-regarded space expert Henry Spencer: _______________________________________________________________________________________________________________ From: Henry Spencer <henry@zoo.toronto.edu> Newsgroups: sci.space.tech Subject: RLV engines (was Re: X-33 Concepts: Lockheed, Mac Dac, Rockwell) Date: Wed, 19 Jun 1996 13:03:12 GMT In article <4q6am4$46s@ns.hcsc.com> andyh@hcxio.hdw.hcsc.com (Andy Haber) writes: >I think this is an area where critics can speak the loudest. Today's >existing engines all leave something be be desired as true, good SSTO engines. >This is mostly due to history. Most engines (other than SSME's) were >designed for ELV's, not SSTO's. Actually, this does not have a lot of bearing on their suitability for RLVs. Most ELV engines are, despite their application, reusable, because they have to be developed and tested. The F-1 was specified for 20 starts and 2250s of life, the J-2 for 30 and 3750s. Six F-1s ran over 5000s each as part of the service-life tests. DC-X's RL10s looked "pristine" after 20 starts; the RL10 is nominally rated for 10 starts and 4000s of firing. >...In terms of using SSME's, sure those can used, >although doing something to reduce the required level on maintenance on >the existing engines is quite desirable... Unfortunately, it probably can't go far enough. Rocketdyne's own estimate was that, with a *lot* of work, you could probably get SSME maintenance costs down to $750k/engine/flight, which is unsatisfactory if you're aiming for really large cost reductions. -- If we feared danger, mankind would never | Henry Spencer go to space. --Ellison S. Onizuka | henry@zoo.toronto.edu _______________________________________________________________________________________________________________ https://yarchive.net/space/rocket/engine_reusability.html Then even reusing the vehicle 10 times could result in a factor of 10 reduction of launch cost, if the maintenance cost could be kept relatively low. That quote about $750, 000 maintenance cost after a lot of work may seem low but from memory I recall it being in the range of $1 million to $2 million per engine after several years into the shuttle program. But how to land the SLS core? Starting the SSME’s is a complex process. Modifying them to be air-startable would not be trivial. Instead, I suggest using the method proposed for making the Centaur a lunar lander, multiple pressure-fed side thrusters for a horizontal landing. Robust Lunar Exploration Using an Efficient Lunar Lander Derived from Existing Upper Stages. Note then that for a stage reenterring to Earth broad-side almost all the reentry velocity is burned off aerodynamically just by air drag so that the stage reaches terminal velocity at approx. 100 m/s. For a stage nearly empty of fuel, this low amount of velocity could be cancelled relatively easily by pressure-fed thrusters with the thrusters running on just the residual of propellant left in the tanks. Robert Clark

About the Centaur as the lander, there is this proposal described here: ToughSF @ToughSf Outline by @ulalaunch for a lunar lander based on the Centaur upper stage. It can use a large and efficient RL-10 engine and then land on its side, bringing its payload close to the Moon's surface. There's variants for crew, cargo, wet workshops and more https://ulalaunch.com/docs/default-source/exploration/dual-thrust-axis-lander-(dtal)-2009.pdf… https://twitter.com/ToughSf/status/1429836316569710594?s=20&t=65-rQRRJheV4YJPO4m02mQ I like the horizontal landing using side thrusters. Note these would be multiple pressure-fed thrusters, avoiding the cost and complexity of pump-fed rocket engines. Robert Clark

You could like the SpaceX Dragon put the launch escape hypergolic thrusters on the capsule, eliminating the launch escape tower. You would have like the Dragon an escape system that worked all the way to orbit. You would then put more propellant on it so the same thrusters could be used for lunar orbit insertion, eliminating the service modules propulsion systems. Note though some of the dry mass of the service module would have to be retained since it contains some consumables and the power systems. Robert Clark

Yes. Note with the larger 170 ton propellant load upper stage, we can get ca. 60 tons to TLI. This allows more propellant to be used for the Orion service module to get the entire stack to low lunar orbit. Then a ca. 15 ton lander a la Apollo only needs to go from low lunar orbit to the lunar surface and back again. Robert Clark

Thanks for running the numbers! I get if we take the delta-v to enter and exit lunar orbit as 800 m/s, it is variable depending on altitude, and the Isp for the hypergolics as 3200 m/s, the crewed lunar lander can be about 50% larger to about 22 tons. Also, note you should separate the cargo and crew flights. I get about 25 tons payload one way to lunar surface using hypergolics with no Orion or service module included. Robert Clark

Those lander concepts in the image are all 40 to 50 tons fueled. Note the Apollo lander was only 15 tons fueled. Perhaps the large size for these Artemis(Constellation?) landers was coming from assuming it would also provide the propulsion for insertion into orbit, a la the Altair lander? Also, the plan using Ariane 5 as upper stage would not go to NRHO, but to low lunar orbit. I think the NRHO idea from NASA came from the limited capabilities of the SLS. This then led to the proposal of the Gateway for the astronauts to loiter at. With the more powerful upper stage you don’t need the NRHO intermediate stop or the Gateway. Let’s say we use an Apollo size lander at ca. 15 tons. Note that even in the SpaceX Starship as lander plan, 2 of the astronauts would remain on orbit in Orion while only 2 would go down to the lunar surface, as with the Apollo lander. So from 60 tons to TLI, with a ca. 27 ton Orion+service module, with a 15 ton lander, you would have 18 tons available for extra propellant to get the stack to low lunar orbit and for the Orion to be returned to Earth. Robert Clark

I did a preliminary calculation that suggests 60 tons or more payload to TLI with a 175 ton propellant load Ariane 5 as upper stage. Note this means it would not need the upgraded SRB’s. I’d like to see though a Kerbal simulation to confirm that TLI payload though. Payload capability this high expands the possibilities for accomplishing the mission, The Orion service module only has about half the propellant load of the service module of Apollo, surprising since it’s a heavier capsule: European Service Module. “In comparison with the Apollo command and service module, which previously took astronauts to the Moon, the European Service Module generates approximately twice as much electricity (11.2 kW vs 6.3 kW), weighs nearly 40% less when fully fuelled (15,461 kg,[24] vs 24,520 kg) and is roughly the same size (4 m in length excluding engine[25] and 4.1 m vs 3.9 m in diameter) supporting the environment for a slightly (45%) larger habitable volume on the crew module (8.95 m3 vs 6.17 m3) though it will carry 50% less propellant for orbital maneuvers (8,600 kg usable propellant vs 18,584 kg).” https://en.wikipedia.org/wiki/European_Service_Module I think the lowered propellant load was specifically so that the Orion could do its circumlunar test flight and the interim upper stage had limited payload to TLI capability. A new mobile launch tower was always planned for the SLS with EUS so that’s nothing new. In this regard, though I wonder if it would be possible to upgrade the current one rather than constructing a whole new one. The lander does not have to be as heavy as the Altair when it is only doing landing to the lunar surface from lunar orbit and back again, The propellant load of the Orion service module though would have at least to be doubled to be able to get the entire stack into lunar orbit. Robert Clark

The name of the game is using existing space assets to save on costs. For both NASA and the ESA there are existing propulsion stages and crew modules that could be used to create a compact sized lander that can fit easily within a 5.4 meter fairing. Robert Clark

The issue with the Mobile Launch Tower 2 is really bad now with the cost nearly tripling. Is there a way to upgrade the current tower by strengthening the base and making the umbilicals telescoping and rotatable? We could use it in the current form for the upcoming test flight. Then have 3 years to complete modification to upgraded form. Robert Clark

Correct the SLS with the Exploration Upper Stage(EUS) was to be the SLS 1B. The version that also has upgraded SRB’s was SLS 2. Still the SLS 1B was supposed to be 365 feet high: The difference in height between the Interim Cryogenic Propulsion Stage(ICPS) currently on the SLS and the Ariane 5/6 would put it at only a couple of meters beyond the 365 feet planned for SLS 1B, and well less than the height of the Vehicle Assembly Building 456 feet high doors. The width of the Ariane 5 is actually slightly more than the interim cryogenic stage now on the SLS so that’s not a problem. The ESA is supposed to be partners with NASA in the Artemis lunar plans, and the ESA is even more interested in Moon colonization than NASA. I then argue they would be amenable to adapting the Ariane for the SLS if it made a Moon lunar flight possible. Note also they were interested in providing the upper stage for the Liberty rocket that was intended to be crew delivery vehicle: https://en.m.wikipedia.org/wiki/Liberty_(rocket) Robert Clark The development cost of the EUS is still not fully funded. Many knowledgeable industry observers feel it will never be fully funded due to its expense. Robert Clark

As discussed in the first part of my cited blog post, ESA believes the Vulcain on the Ariane 5/6 can be made air startable as an upper stage since that was required for the proposed Liberty rocket: Budget Moon Flights: Ariane 5 as SLS upper stage. http://exoscientist.blogspot.com/2013/07/budget-moon-flights-ariane-5-as-sls.html Note the Liberty rocket was intended to also be crewed so the Ariane would have had to be man-rateable: https://en.m.wikipedia.org/wiki/Liberty_(rocket) Robert Clark

The SLS was planned to have a large upper stage called the Exploration Upper Stage(EUS). This would take the SLS Block 1 to the SLS Block 2, needed for a single flight lunar architecture. However, the multi-billion dollar cost for development of a large upper stage from scratch means it’s unlikely to be funded. NASA is proposing a solution using the Starship making separate flights. But this plan takes 6 flights total or likely more of the Superheavy/Starship for the Starship to fly to the Moon to act as a lander. One look at this plan makes it apparent it’s unworkable: Actually, it’s likely to be more complex than portrayed in the figure, needing 8 to 16 refueling flights. This is what SpaceX submitted to NASA in proposing the plan, requiring 6 months to complete the Starship refueling: SpaceX CEO Elon Musk details orbital refueling plans for Starship Moon lander. By Eric Ralph Posted on August 12, 2021 First, SpaceX will launch a custom variant of Starship that was redacted in the GAO decision document but confirmed by NASA to be a propellant storage (or depot) ship last year. Second, after the depot Starship is in a stable orbit, SpaceX’s NASA HLS proposal reportedly states that the company would begin a series of 14 tanker launches spread over almost six months – each of which would dock with the depot and gradually fill its tanks. … In response to GAO revealing that SpaceX proposed as many as 16 launches – including 14 refuelings – spaced ~12 days apart for every Starship Moon lander mission, Musk says that a need for “16 flights is extremely unlikely.” Instead, assuming each Starship tanker is able to deliver a full 150 tons of payload (propellant) into orbit after a few years of design maturation, Musk believes that it’s unlikely to take more than eight tanker launches to refuel the depot ship – or a total of ten launches including the depot and lander. https://www.teslarati.com/spacex-elon-musk-starship-orbital-refueling-details/ Everyone, remember the Apollo missions where we could get to the Moon in a single flight? In fact, this would be doable with the SLS given a large upper stage. Then the suggestion is for the ESA to provide a Ariane 5 or 6 as the upper stage for the SLS. It would save on costs to NASA by ESA paying for the modifications needed for the Ariane core. As it is now ESA is involved in a small role in the Artemis lunar program by providing the service module to the Orion capsule. But it would now be playing a major role by providing the key upper stage for the SLS. The argument might be made that the height of the Ariane 5/6 is beyond the limitations set forth by NASA for the EUS. However, if you look at the ca. 30 m height of Ariane 5 core compared to the 14 m height of the interim cryogenic upper stage now on the SLS, this would put the total vehicle height only a couple of meters beyond the height that had already been planned for the SLS Block 2 anyway: See discussion here: Budget Moon Flights: Ariane 5 as SLS upper stage, page 2. https://exoscientist.blogspot.com/2013/09/budget-moon-flights-ariane-5-as-sls.html Coming up: ESA also could provide a low cost lander for the Artemis program. Robert Clark

Dragon has its own built in emergency escape system using the Superdracos. But I think because the Starship tanker version has a greatly reduced dry mass without the passenger compartment, it might be doable in a single flight, no refueling flights required. Robert Clark

I don’t think many people even space advocates realize the complexity of the current Moon plan. Remember, in addition to the 8 to 16 refueling flights it also includes the SLS: How NASA Plans To Use The Orion Space Launch System & SpaceX Starship To Land The Next Astronauts On The Moon. by Evelyn Janeidy Arevalo January 09, 2022 NASA SpaceX Starship https://www.tesmanian.com/blogs/tesmanian-blog/sls-hls-2025 I’m looking for a much simpler architecture IF you had a 3rd stage. The size of the 3rd stage I’m leaving open. I only used the Starhopper as a convenient reference point as something that could have been available now IF its development was continued. You could have had a fully reusable manned lunar rocket. That would go a long way to making lunar flights common and for accomplishing the Moon colonization plan. Moveover the 3-stage reusable launcher would work for Mars missions using a single launch. Note well: IF the 3rd stage had been pursued then by the launch of Starship later this month or the next we would already be capable of manned Moon or Mars missions. In contrast, it will take years for the 8 to 16 launch architecture to be ready for lunar or Mars missions.

Previously, I would have discussed this on Reddit in r/SpaceXLounge, but with the new moderation there they won’t let you discuss anything controversial or speculative. Starship and modeler pics seem to be the name of the game now. For several years I’ve been thinking of mission architectures that could get us back to the Moon by the 50th anniversary of the Apollo manned lunar missions. We missed the Apollo 11 50th anniversary, but we MIGHT have been able to make the Apollo 17 50th anniversary of Dec. 2022. This is where it gets controversial. The SpaceX architecture of making 8 to 16 refueling flights for Moon or Mars flights is a bad architecture. There is a reason why the Apollo missions used a launcher with 3 stages and then 2 more stages for the lander for their round-trip missions. For missions with that high a delta-v requirement multiple stages are critical. SpaceX by using multiple refueling flights is acknowledging that, just in a very inefficient manner. The point of the matter is SpaceX could have done a manned Moon or Mars flights with a single launch IF they had given their launcher a 3rd stage. The 3rd stage could have been comparable size to the Starhopper. Yes, I know the actual Starhopper was not space-worthy but the point of the matter is by continuing it’s development along side the Starship they would have had a space-worthy vehicle capable of lunar landing and return by now. SuperHeavy+Starship+Starhopper single launch missions to the Moon or Mars. It would have been so beautiful … See here: http://exoscientist.blogspot.com/2019/07/starhopperstarship-as-heavy-lift.html Anyone up to the challenge of a sim? Robert Clark

An interesting article discusses a curious law seen in astronomy: angular momentum of a planet, star, or galaxy is proportional to the square of its mass: Cosmic Carousel 19 December 1998 By Robert Matthews If his idea is right, conservation of angular momentum would ensure that evidence would be visible today. Carneiro suspects it is—in the form of a mysterious “law” discovered in the 1970s, when astronomers found that the angular momentum of a planet, star or galaxy is proportional to the square of its mass. https://www.newscientist.com/article/mg16021652-500-cosmic-carousel/

Here’s an article on a different peer-reviewed published proposal for a warp drive, This one remarkably does not require negative energy: Star Trek’s Warp Drive Leads to New Physics Researchers are taking a closer look at this science-fiction staple—and bringing the idea a little closer to reality By Robert Gast, Spektrum on July 13, 2021 https://www.scientificamerican.com/article/star-treks-warp-drive-leads-to-new-physics/ Robert Clark

Looks to work on the same principle as ionocraft: Then the key impediment is lightweight power supplies. So far they have to be powered by attaching power leads from the ground. Robert Clark

Actually, I was basing the 10 tons estimate on how much propellant I had once estimated would be left over in the FH upper stage if it only had to get a smaller payload mass to TMI. I then imagined doing a propulsive landing on Mars. But that’s really not the aerocapture method I was thinking of here. Perhaps someone could do a Kerbal Realism Overhaul of a Falcon Heavy upper stage propulsive landing on Mars. Robert Clark

According to this article, NASA support for the mission was cancelled for political reasons: https://news.ycombinator.com/item?id=26274117 Robert Clark

‘Red Dragon’ can also do it launched atop the Falcon Heavy: 'Red Dragon' Mars Sample-Return Mission Could Launch by 2022 By Mike Wall September 10, 2015 https://www.space.com/30504-spacex-red-dragon-mars-sample-return.html It would use though both aerobraking and propulsive landing. This article claims ‘Red Dragon’ was cancelled only for political reasons: https://news.ycombinator.com/item?id=26274117 By the way, looking at that delta-v map again, it looks like for a fully aerocapture approach to landing at both Mars and Earth, you could get greater mass to Mars. I was considering a 10.2 km/s delta-v each way to Mars and back, but part of this is for propulsive burns when arriving at Mars, or returning to Earth. If you do a fully aerocapture descent, i.e., aerodynamic slow down, with parachutes when sufficiently slowed, then you just need to do a Trans Mars Injection burn and this only takes ca. 3.8 km/s. And the Falcon Heavy can launch 16.8 tons to Mars on this trajectory. This would then make a direct descent to the Mars surface. Note the higher mass means we could add additional aerodynamic surfaces to assist with the slowdown on arrival at Mars. Also, for return to Earth, if this is fully aerodynamic, the delta-v for this is only around 6.3 km/s. So a larger mass could be returned from the Mars to Earth. Robert Clark Part of the reason why Apollo was multi-billion. For instance for the current sample return plan they want the Mars Ascent Vehicle to rendezvous with an orbiting spacecraft and then be launched by a another stage to Earth. Far simpler and cheaper to launch directly from Mars surface towards Earth. Robert Clark

NASA has collected its first Mars sample. But it needs $4 billion, 10 years, and new technology to bring the rock to Earth. https://www.businessinsider.in/science/news/nasa-has-collected-its-first-mars-sample-but-it-needs-4-billion-10-years-and-new-technology-to-bring-the-rock-to-earth-/articleshow/86051685.cms Take a look at the delta-v map above. It takes about 10.2 km/s total delta-v each way to go to and from Mars. The Falcon Heavy can get about 16.8 tons to Trans Mars Injection, where TMI is the propulsion step to head towards an encounter with Mars, that is, meet it in its orbit about the Sun. Then I estimate with a smaller 10 ton payload the Falcon Heavy’s upper stage could land a 10 ton payload on the surface of Mars by using aerocapture , which minimizes the propellant required to do the landing. This then allows a wide variety of combinations of existing solid rocket motors, 3 stages, such as from the Star series to make up the 10.2 km/s required delta-v to return from Mars. All these are existing elements so could be mounted, like, tomorrow, and at a few hundred million dollar cost. Robert Clark

Well done. Thanks for that. Robert Clark