Illustration of SpaceX’s Falcon Heavy launch vehicle (Credits: SpaceX),.

Illustration of SpaceX’s Falcon Heavy launch vehicle (Credits: SpaceX),.

There have been occasional suggestions that NASA should scrap its Space Launch System (SLS) in favor of SpaceX’s Falcon Heavy for fulfilling its beyond low-Earth orbit space exploration needs [1]. The claim forwarded by some is that the as-yet-untested-and-unflown 53 mt low-Earth orbit (LEO) (200 km @ 28°) Falcon Heavy is now “cheaper” than the as-yet-untested-and-unflown SLS. Furthermore, canceling the SLS would supposedly save NASA $10 billion—money that could otherwise be used to fund such programs as the Commercial Crew integrated Capability (CCiCap), to conduct a flight test of Orion on a Falcon Heavy, and to focus on building a small-scale space station in the area near the Moon. One issue not addressed by proponents of canceling SLS is whether it is a good idea to couple a nation’s human exploration spaceflight capabilities to a private company. An issue which appears to be altogether ignored, is the Falcon Heavy’s small lunar payload capability and the impact this would have on an already complex and risky endeavor such as lunar exploration.

According to SpaceX, the Falcon 9 Heavy, also called the Falcon Heavy, will have a 53 mt (metric ton) payload capacity to LEO of 200 km with an inclination of 28° [2]. Such a LEO payload capability will be impressive, allowing SpaceX to launch nearly twice the payload of a Delta IV Heavy or an Atlas V, and to do so more cheaply than either. But when it comes to launching payload to a geostationary transfer orbit (GTO) or beyond, the Falcon 9 Heavy falls far short of either the Delta or Atlas launchers. With a GTO payload of barely over 12 mt, the Falcon 9 Heavy is at least 1 metric ton, or 1,000 kg, under what either the Delta IV Heavy or Atlas V can deliver to the same point in space.*

The Falcon 9 Heavy’s GTO payload deficiency relative to the existing EELV launch vehicles has other down-stream effects as to its appropriateness for beyond-Earth orbit (BEO) crewed exploration. It is safe to assume that the Falcon Heavy’s low-lunar orbit (LLO) payload capacity will not top much above 10 mt [3]. How will the Falcon 9 Heavy’s meager LLO payload capacity enable a meaningful return to the Moon? And why even talk about the Falcon Heavy as a possible launcher of crewed lunar exploration when each of the Delta IV Heavy and Atlas V launchers can send over 1,000 kg more than the Falcon Heavy to the Moon? Moreover, while the Delta IV and Atlas V have extensive flight histories, the Falcon Heavy has no such experience.

The Falcon 9 Heavy is, much like United Launch Alliance’s Delta IV Heavy, a triple-bodied version of the company’s Falcon 9 launch vehicle (Credits: SpaceX).

The Falcon 9 Heavy is, much like United Launch Alliance’s Delta IV Heavy, a triple-bodied version of the company’s Falcon 9 launch vehicle (Credits: SpaceX).

Advocates of using the Falcon Heavy don’t just want to rewrite who takes us beyond-Earth orbit, but more fundamentally how such missions are built. Reliance upon the Falcon Heavy for launching a beyond-Earth exploration program means some hard choices as to mission architecture. Traditionally, crewed exploration beyond low-Earth orbit has focused on minimizing complexity, and therefore risk and cost, by using a heavy-lift rocket (HLV). The logic behind using an HLV for lunar exploration in the past was that fewer launches correlated to less risk. The Falcon Heavy’s 10 mt capability means that any lunar exploration program will have to be one of assembling pieces/parts in low-Earth orbit, where the Falcon Heavy’s (LEO) 53 mt payload capacity can really shine. Some have claimed that centering a beyond-Earth exploration program on the Falcon Heavy does not mean ending the Orion spacecraft program. They point this out because Orion is the only spacecraft designed from the ground up for beyond-Earth exploration. Certainly, a Falcon Heavy can place an Orion crewed and service module in low-Earth orbit. But several additional launches will be needed to send Orion and her crew to the Moon. A lunar crewed mission using the Falcon Heavy would mean assembling, at necessary LEO locations, a crewed vehicle, a lander, a trans-lunar injection stage, a stage to get the crewed spacecraft and lander into LLO, and possibly a separate stage to enable the crewed spacecraft to return to Earth [4].

– Below, a SpaceX promotional video for the Falcon Heavy.

[cleveryoutube video=”UTwRxtmQ9IY” vidstyle=”1″ pic=”” afterpic=”” width=”” quality=”inherit” starttime=”” endtime=”” caption=”” showexpander=”off” alignment=”left” newser=””]

Falcon Heavy To The Moon

While supporters of an all-commercial approach frequently tout the company’s laudable accomplishments, they just as frequently ignore the limitations of both the Falcon Heavy launch vehicle and the Dragon spacecraft (Credits: SpaceX).

While supporters of an all-commercial approach frequently tout the company’s laudable accomplishments, they just as frequently ignore the limitations of both the Falcon Heavy launch vehicle and the Dragon spacecraft (Credits: SpaceX).

One problem with a non-HLV approach to lunar exploration is that if a replacement Falcon Heavy and payload are not handy, any launch failure could very well mean a scrubbed mission. So a non-HLV approach necessarily means an inventory of not just a spare Falcon Heavy, but of duplicate spaceflight hardware—or designing hardware and refueling stations such that a delay of weeks or months would have only a marginal impact on the mission. Solving all of these unknown-unknowns (or unk-unks in engineering speak) associated with multiple launches, assembling a mission in LEO, in-space refueling at an orbiting location, among others flowing from a non-HLV approach to beyond-Earth exploration, could see the cost advantage of using the relatively unproven Falcon Heavy largely, if not completely, evaporate.

A beyond-Earth exploration program using the Falcon Heavy in an HLV architecture has its own downsides and associated costs. In order to enable the Falcon 9 Heavy to be a capable beyond low-Earth orbit launcher, funds will certainly be needed to create a new cryogenic second-stage. This will be needed because, in its current configuration, a Falcon 9 Heavy could not even launch one 11.6 mt Unity node module, much less a 20 mt Bigelow BA 330 Nautilus module. Even with a brand new second-stage, reliance upon the Falcon 9 Heavy to build, visit, and maintain a lunar orbiting outpost will dictate doing so in very small chunks; the number of launches will then begin to add-up, as will the complexity, risk, and cost. A Falcon Heavy cannot place an Orion spacecraft even in high-Earth, much less lunar, orbit. So reliance upon the Falcon 9 Heavy for beyond low-Earth missions in an HLV-based lunar mission architecture would only set NASA up to cancel Orion and go with Dragon for our nation’s crewed space exploration needs.

The Dragon Spacecraft And Lunar Exploration

While it may be true that the Dragon spacecraft has a heatshield capable of allowing the spacecraft safe reentry into the Earth’s atmosphere, little else of Dragon is crew, much less lunar mission, capable. SpaceX’s Dragon is currently a participant in NASA’s commercial crew and cargo programs. One goal of NASA’s commercial crew program is to enable spacecraft built and operated by commercial space companies to get crews to and from the International Space Station by late 2017. But the requirements for a crewed spacecraft tailored for low-Earth orbit are different than those for beyond-Earth orbit. For one, a LEO capable spacecraft need only be capable of hours of operation, where a lunar spacecraft needs a capability of days. This means that the use of the Falcon Heavy as a means to returning humans to the Moon very likely means funding further enhancements, and verifying those enhancements to the Dragon spacecraft. As with over 90 percent of the funding for Falcon 9 and Dragon, this additional financial burden would fall upon NASA’s, and therefore the U.S. taxpayer’s, shoulders. Even with an enhanced Falcon Heavy launcher and Dragon spacecraft, more than one Falcon Heavy launch would still be needed to support a crewed lunar landing mission. Several Falcon Heavy launches would be needed to build a lunar orbiting outpost.

– In the video below, a documentary about NASA SLS.

[cleveryoutube video=”bzFwxHNKSAo” vidstyle=”1″ pic=”” afterpic=”” width=”” quality=”inherit” starttime=”” endtime=”” caption=”” showexpander=”off” alignment=”left” newser=””]

Advantages Of SLS Over Falcon 9 Heavy

As it currently stands, neither NASA’s Space Launch System nor SpaceX’s Falcon Heavy have a proven track record. However, it would take multiple launches to accomplish what SLS could in a single flight (Credits: NASA).

As it currently stands, neither NASA’s Space Launch System nor SpaceX’s Falcon Heavy have a proven track record. However, it would take multiple launches to accomplish what SLS could in a single flight (Credits: NASA).

NASA could send a crewed lunar mission or build a lunar outpost with far fewer SLS launches. That’s because the very first iteration of the SLS, the Block I, will carry twice the payload of a Falcon Heavy to the Moon. The SLS Block II will have a lunar payload capacity nearly 3–4 times that of the Falcon Heavy, depending upon what engines are selected for the SLS’s advanced booster.

Beyond the SLS’s substantial payload advantage for lunar missions, the question of cost remains. Are 3 or 4 Falcon Heavy launches really cheaper than just one SLS Block II launch? That is a hard question to answer given that both launchers are still effectively “paper” rockets. In factoring launch costs, there is the cost of the launch vehicle, the launch pad, launch support, and post-launch management, just to name a few.

The bigger problem for those wishing to end the Space Launch System program is that it is currently ahead of schedule. According to John Elbon, Boeing VP & General Manager, Space Exploration, “We’re on budget, ahead of schedule. There’s incredible progress going on with that rocket” [5]. Canceling a rocket that is ahead of schedule would be difficult at best. Given that Congress has, over three votes, not only supported SLS but increased its funding over amounts sought by the Obama Administration, the odds of opponents getting SLS canceled are slim-to-none.

NASA’s SLS has the full support, to include funding, of Congress. As such, efforts to cancel the system in lieu of one that favors the company that SpaceX supporters approve of is not likely to occur. (Credits: NASA).

NASA’s SLS has the full support, to include funding, of Congress. As such, efforts to cancel the system in lieu of one that favors the company that SpaceX supporters approve of is not likely to occur. (Credits: NASA).

Space Launch System opponents suggest that the SLS program should cancel until a mission requiring such a rocket is identified. John Shannon, also with Boeing, recently stated, “This ‘SLS doesn’t have a mission’ is a smokescreen that’s been put out there by people who would like to see that [program’s] budget go to their own pet projects. SLS is every mission beyond low Earth orbit. The fact that NASA has not picked one single mission is kind of irrelevant” [6]. It bears mentioning that a good part of the reason there is no meaningful mission for the Orion-SLS is because the Obama Administration has not agreed with Congress that, as Congress noted in its 2010 NASA Authorization Act, cislunar space is the next step in our efforts beyond Earth and that the SLS is an integral part of that step.

Moreover, both short- and long-term missions for SLS have emerged in recent months. Within the 2014 FY Budget Proposal Request, NASA was directed to retrieve an asteroid, place it in lunar orbit, and then send astronauts to study it. The vehicle of choice is SLS. During a recent interview, NASA Deputy Associate Administrator for Exploration Systems in the Human Exploration and Operations Mission Directorate Dan Dumbacher stated on AmericaSpace that the long-term mission for SLS was to send astronauts to Mars.

This article is reposted from with permission of the publisher. Opinions expressed are those of the author and do not necessarily reflect the views of Space Safety Magazine, the International Association for the Advancement of Space Safety, or the International Space Safety Foundation.

  1. A Rocket To Nowhere (Aviation Week & Space Technology, April 18, 2013 
  2. Falcon Heavy Overview 
  3. SpaceX did not respond to AmericaSpace inquiries concerning the Falcon Heavy’s LLO payload capacity. 
  4. SpaceX did not respond to AmericaSpace inquiries concerning the Dragon trunk’s trans-Earth injection capability. 
  5. NASA’s Mars-Bound Mega Rocket on Track for 2017 Test Launch 
  6. Boeing Executive Defends SLS as Only Deep-Space Option, John Shannon quote 

*Editor’s note: these values appear to have been accurate at the time this article was published. As our astute readers have pointed out, SpaceX’s currently published nominal GTO payload capacity of the Falcon Heavy is 21,200 kg, which naturally impacts this analysis.


About the author


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AmericaSpace was founded in 2009 by two former aerospace engineers. Since then, this site has been dedicated to reporting on the state of America’s space and aerospace efforts, which for many have been, and remain, synonymous of America’s willingness, indeed enthusiasm, to reach new horizons. As America’s human space flight program transitions from the Shuttle program to one focused on beyond earth exploration, AmericaSpace will continue to cover this evolution in spaceflight while expanding our coverage of aeronautics, milspace, and planetary exploration. We do this for one simple reason… Because America is a nation that explores.

30 Responses

  1. Scott Rankine

    A well written and thoughtful piece with one small problem – NASA’s $10B SLS project is a rocket to nowhere.

    The SLS is a post-shuttle make work program using recycled sparts forced on the agency by aerospace lobbyists and their GOP cronies. It will never fly, not after SpaceX launches the Falcon Heavy this year and moves ahead with its plans for a reusable super heavy and follow-on Mars rocket (BFR) with a capacity that dwarfs anything the SLS could deliver.

  2. McDiver

    NASA does not build rockets. NASA has already “coupled a nation’s human exploration spaceflight capabilities to private companies”. NASA does not build the SLS, its contractors do. A fine piece of double talking smoke and mirrors. Do you own stock on a government contractor that is building rockets for NASA?

  3. Ryan

    Though I do like the article, they seem to paint SpaceX as a company limited to LEO. For now that is true, but should they complete testing of the grasshopper and create the reusable rocket it will substantially reduce the cost. If they go reusable, the fuel for a Falcon 9 launch is roughly $250,000. Add on the price of mission control, profit for the company, etc. that still is significantly cheaper than $54-59.5 million price tag to launch one now(it is $435 million for Atlas V or Delta IV if i remember correctly). The Falcon heavy is to launch between $90-120 million when first ready. When it is reusable that too will drop.

    What was not said in the article was anything about SpaceX developing the Merlin 2 engine. If the Merlin 2 comes out at its predicted 1.2-1.4 million lbs. of thrust when finished, that will give more than enough power to extend the reach of SpaceX rockets. Also, as Scott stated, they are looking at making HLV’s down the road. Reusable if they have safely demonstrated it. This can be seen in the link(below) of how they plan to out power the other contractors for a fraction of the cost. Sorry for being lengthy, but I wrote a 38 page paper comparing SpaceX, Virgin Galactic, and NASA. Cheers!

  4. Doug Messier

    According to an article over on Space News, SLS is set to fly in 2017, 2021 and 2025. That’s a launch of once every four years. It’s difficult to imagine building or sustaining much of anything on the moon or Mars or deep space with a launch rate like that one. SLS is saddling NASA with a rocket that’s too expensive to fly and operate. And this doesn’t even take into the account the safety issues associated with such a low launch rate.

    Falcon Heavy will cost much less to fly and will benefit from the economies of scale of SpaceX’s satellite launch business. So, NASA could purchase multiple Falcon 9s from SpaceX for the cost of one SLS. And not have the enormous expense of maintaining the SLS assembly line.

  5. sftommy

    One might have led the article with Elon’s agreement with the need for a heavy lift vehicle beyond his own Falcon-Heavy. For SpaceX to gain that wanted launch capability they admit they’d need a new engine and $1B to develop it.

    ULA’s products are overpriced, whatever bias that can be substantiated, they are still overpriced. That overpricing is being protected by members of Congress on both sides of the aisle and is being carried over into SLS. That limits anything that can be achieved with that vehicle, achievements in space will have to work with and around those limits.

    I put more faith in Elon’s plan for getting to Mars than Congress’ and fear NASA will be playing catchup to SpaceX and those countries that follow the SpaceX model come the 2020’s.

  6. Scott Rankine

    I agree that the path NASA is being forced down by narrow minded special interests groups will ultimately do the agency and US tax payer a great disservice. however, it won’t be long to everyone of every political stripe and bias (even the dim witted cronies over at fox) will be forced to admit they backed the wrong horse…

  7. Artur

    This article is skewered. Heck, NASA could order a Falcon Heavy with a ULA cryogenic upper stage. Why stick to one company. NASA is know to mix & match the capabilities of private launch companies. Take the best of SpaceX ie …Falcon Heavy & replace the upperstage with the best of ULA’s upperstages…bam…Capability increased. Even Von Braun proposed the assembly of spacecraft in low earth orbit for luna & mars missions. Yes you could do a luna mission less expensive with Delta IV Heavy, Atlas V, Falcon Heavy & Falcon 9 all launching within days of each other & assembling in LEO. It comes out to approximately 109 metric tons. Add the Japonese & Europeans & you have an additional approx 36 tons to LEO. So total LEO tonnage would be 145 tons or approx 321,000 lbs. Of course coordinatin is the key.

  8. anonymous

    This article ignores several important facts.

    1) Three Falcon heavy launches will most likely be cheaper then one SLS launch given the history of space X and the History of NASA. That does not even count savings from being reusable

    2) They are comparing a small launch vehicle like Falcon Heavy to a large one like SLS. If they want a larger vehicle from SpaceX, they could always take the existing funding of SLS now and put it toward the Falcon 20.

    3) Government relies on companies to do things all the time. After all, the government gets most of its technology from businesses. You don’t see complaints that the government should fund its own technology company so it doesn’t have to be reliant on businesses to invent things for them.

  9. Ben

    The specifications for the Falcon Heavy used in this article are way off currently published numbers.

    SpaceX is currently advertising 21 metric tonnes to GTO, not 12. Still lower than SLS, but significantly higher than either the Delta IV or Atlas V.

  10. Michael

    “Are 3 or 4 Falcon Heavy launches really cheaper than just one SLS Block II launch? That is a hard question to answer given that both launchers are still effectively “paper” rockets. In factoring launch costs, there is the cost of the launch vehicle, the launch pad, launch support, and post-launch management, just to name a few.”
    The stated commercial price, and therefore TOTAL cost, of Falcon Heavy is $77million for 45MT to LEO and $135million for 53MT to LEO. 130T to LEO will cost The REAL cost of each SLS launch, including all development, manufacture and operations, will be in the region of $4Billion plus payload. So the cost of 130MT to LEO by SLS will be at least $4BILLION. $4 billion of FH launches will put over 2,300MT to LEO. 3 launches of Falcon Heavy will put 130MT in LEO for less than 6% of a single SLS launch, so yes, 3 or 4 launches of FH will really be cheaper than SLS. The cost of FH to any and all commercial or government or space agency customer is a known figure, with no doubts, speculation or financial risk of hidden extras or the adding of unexpected billions.

    As for “paper rockets”, Falcon Heavy is already developed and will launch early 2014. Every Falcon 9 v1.1 launch is a test of FH tech. Of course, reusability of first stages has not happened yet, but I would far rather bet on Spacex achieving this before 2017, than SLS being built on time and on budget.

    Elon Musk speaks with confidence of Dragon being capable of Mars return re-entry velocities. Dragon prices are not published, you can be fairly confident that somewhere under $100 million will be a safe bet. The only advantage Orion has for longer duration missions is a new life support system, which has no yet been developed, and an ESA supplied propulsion unit, that has not yet been fully developed yet. Somehow the development of just the Orion so far has already cost $6billion and will easily top $10billion by the firdst manned flight in 2021. Dragon 2, will likely has flown dozens of times by then.

    I am quite happy to plead guilty to Spacex optimism. That notwithstanding, I am quite impressed with the extent to which the author has placed his intellectual credibility on the line. There may be a few bumps along the way, but the quality of the arguments in this article are almost beyond belief.

  11. Yale S

    I am confused by this article. The Falcon Heavy has almost twice the GTO mass capability of the Delta IV heavy or the Atlas. The whole article is based on totally backwards numbers. What’s up with that?

  12. Kevin Hambsch

    you are way off! Mr. Musk even said two launches would be required for a “same as” or “slightly bigger” Apollo type mission. It all, however, boils down to cost. One falcon heavy is a fraction of the “projected cost” for an SLS launch, and we all know about government costs coming in as project and on time. LOL!

  13. Alex

    I guess you didn’t know that each of the SLS’s boosters has 3,600,000 lbf of thrust… And that’s just the first version.

  14. Alan

    Reusability is great, but I think you overstate just how much gain is to be had from it. With Spacex’s plan of retrograde boosting, a significant amount of propellant is reserved for recovery which will cut into performance.

    Don’t discount manufacturing costs either. Even reuasable, each rocket will have a finite number of launches before it can’t be salvaged. There are also bound to be significant refurbishing and testing costs in between each flight.

  15. MJ

    I am as huge a fanboy of Space X as anybody. They have done a great job so far and I can’t wait to see where they will take us. The Falcon 9R will shake up the launch industry. However, as much as the SLS is a money sucking boondoggle pork pig, Space X needs to do a little more before warranting great expenditures of tax dollars on vaporware. Let’s see what a Falcon heavy can actually do. If they are able to pull off a successful demo launch of that rocket, I would be the first one screaming for them to at least work in tandem with NASA to launch materials to build in space, weather it be for the moon or another destination. It would be foolish to not team up, given the amount of material that can be put into orbit by combining forces of SLS, Space X, and ULA. To me, it all rides on a successful demo launch of the Falcon H.

  16. Arthur Little

    Intersting article which I enjoyed reading. One point however jumped out at me which I feel needs to be corrected. As stated on the SpaceX website the GTO payload capability of the Falcon Heavy is 21,000 mT, the Atlas V GTO is 13,000 mT and the Delta IV GTO is 12,999 mT. My source for SpaceX was their website and my source for both the Atlas and Delta was Wikipedia; all retrieved 2014-02-07. I think you owe it to your readers to make a correction.

  17. Merryl Azriel

    Thanks for the comment, Arthur. I appreciate you pointing out the discrepancy in payload capacity cited in our article. You are quite right, the Falcon Heavy GTO is supposed to be 21,200 kg, much exceeding ULA’s vehicles. After contacting the author, we will certainly make appropriate corrections to the article.

  18. GS

    Where’s the correction? I came across the article while doing research. It’s propogating misinformation.

  19. Merryl Azriel

    The incorrect value is asterisked with the correct value in the footnote.

  20. gajbooks

    WRONG. The Falcon 9 Heavy can carry up to 21 metric tons to GTO in fully expendable configurations, which is significantly more than either the Delta IV Heavy (14 metric tons) or the Atlas V (9 metric tons).

  21. Bernard Michael


    Delta IV Heavy – total number of launches = 8
    Atlas V – total number of launches = 61
    Falcon 9 Heavy – total number of launches = maybe next year

    So, for another 12 plus months, at an absolute minimum, Falcon 9 Heavy can lift exactly 0 tons to ANY orbit.

  22. gajbooks

    Since this is an article about Moon exploration, and test missions probably couldn’t occur for at least three or four years, your argument is invalid. Also, this article compares the SLS to the Falcon 9 Heavy, and if I recall correctly, it doesn’t exist either!

  23. Vlad_Von_Bazza

    Both the Atlas and the Delta are not qualified for grew. But the Falcon has always been designed ultimately to take crews. And if you’re going to compare the 2 rockets then do it properly. By that I mean cost to the tax payer. The SLS will ultimately cost the tax payer 10s of billions to develop. The FH R & D will cost them zip! But hopefully the SLS will die of embarrassment and contraversy before its completed.

  24. The Historical Gamer

    The SLS’s 10 billion R&D cost is already almost all spent. Canceling it wouldn’t save much of that money because it’s already been spent. The real comparison at this point is cost per mission.

  25. Vad_Von_Bazza

    Fair enough. But if we were to compare “cost per mission” Is there really any point? Launch cost for the SLS alone is thought to be around 1 billion dollars and that’s not including static costs which could be double that. FH. 130 million. SpaceX can do it for a minuscule amount. Its for that reason that articles like this one are so worthless.

  26. The Historical Gamer

    Not really that’s why I said cost per mission not per launch. The Falcon heavy carries 20 tons less into orbit and only 1/4 as much out of orbit. So even if the FH is much cheaper per launch the SLS can do in 1 rocket what the FH will take 4-5 launches to do. Also the SLS per launch costs are slated to be between 500-700 million. The Falcon Heavy would take 5 launches to equal the lunar payload of a SLS which at 90 million (on the low side) per rocket only gives the FH a slight advantage in cost (450 to 500) and the likelyhood of failure is far greater on 5 launches than it is on 1. In short the FH isn’t a very good option for a heavy lift interplanetary rocket because its interplanetary payload is lower than even the Atlas V or Delta IV it’s only advantage over those is it will be man rated.

  27. Vlad_Von_Bazza

    Point taken about multiple launches. but I must re-state. FH prices include all other costs. The SLS has been estimated in the billions to the customer. That’s what’s missing from your wallet after the bill is paid. Even totalling up 5 launches. SpaceX may still beat SLS by a factor of 10.
    And one more thing. I think the SLS emerged from the Ares 5 program. So the billions spent on the R & D for that should be mentioned.

  28. The Historical Gamer

    If you’re doing a post mortum then sure mention those costs but if it’s already been spent it should be ignored as far as making decisions about the future. Sunk costs are irrelevant to what’s the better choice moving forward. Further the SLS is undoubtedly more capable for deep space missions. That’s it’s key value. Theoretically you can do multiple launches to make the FH equivalent and yes it may be cheaper still but each launch significantly increases your risk of failure and you can’t ignore that just due to cost. If it fails you waste everything!

  29. Vlad_Von_Bazza

    I think there is a value to mentioning past expenses as a warning to the tax payer.of future expenses. If wikileaks is to be trusted. The SLS still has another 10 billion to spend until 2023 regardless of launches. So again may I stress that SpaceX aren’t just cheaper, they are ridiculously cheaper. Seriously, is it not enough to point to Elephant in the the room? Also according to gajbooks comments (see below) the FH in its expendable mode is far more capable requiring less launches. But finally, can we all please pull our heads out of the 1960s and accept the fact that the future of space flight will involve lots of docking. Or perhaps you’d also want someone to suit up and float in front of the Orion capsule carrying a red flag.

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