The Space Launch System has been the subject of heated debate, but what’s the alternative to going to the Moon, Mars and beyond? (credit: NASA) |
by Ajay Kothari
Monday, March 15, 2021
Several days after Bloomberg’s editors recommended the Biden administration to cancel the Space Launch System (SLS), Loren Thompson posted a rebuttal in ForbesBut I respectfully, albeit strongly, disagree with Thompson. The future of the SLS is of immense importance to NASA and the country, and thus to the taxpayers, so we must try to get things right as soon as possible.
Thompson says, “Bloomberg News’ editors launched a nonsensical attack on NASA’s manned space flight program last week. It was full of dubious claims about alternatives to the Space Launch System. And yet it is his attack that seems self-centered and full of questionable claims.
Yes, as the Bloomberg editorial said, SLS should be dropped. But not only that, we need to change the paradigm of how we do space travel. Building an ever-larger missile each time to fit into a larger mission, the crux of Thompson’s argument, is asinine and unnecessary. With the arrival of many reusable rockets from SpaceX, Blue Origin and hopefully Rocket Lab soon, we are in a different territory. Let’s take advantage of it as a country, or someone else will do it first.
The problem, put simply, is that larger payloads and more distant destinations require more propellant, which in turn requires larger missiles to boost them. So our plans are also limited in what we have available that day in terms of missiles.
| Building an ever-larger missile each time to fit into a larger mission, the crux of Thompson’s argument, is asinine and unnecessary. |
What if we don’t have to be constrained in this way? This is possible by linking multiple upper stages in low Earth orbit (LEO), one with the payload and all others with that much extra fuel through the same reusable booster (s). Refueling is not necessary for the time being, as the Forbes article posited as alarm – maybe that could come later. In geek language, what this does is increase the propellant fraction until it is equal to what it takes to get the job done. This gives us the opportunity to have theoretically infinite solutions for space travel, basically tailored to the need. Do you want to go to the moon? Two flights of Falcon Heavy. Do you want to go to Mars instead? Four flights of Falcon Heavy. Need a little extra boost? Rocket Lab’s new Neutron can fill the gap. A bigger gap? New Glenn or Blue Origin can help.
It builds a railroad to space with thousands of solutions at your fingertips. Let’s build this railway instead of the one-off solutions like SLS. This is not rocket science!
This was not possible before. But now the reusable rockets have proven to be significantly cheaper to fly, and the upper stages have less weight. It’s almost a gamble that many other countries, especially China, will follow this method and leave us in the dust if we don’t apply it. China is already developing reusable missiles. If we stick to the current status quo, we’ll lose this race to China, which will have thousands of possible paths to NASA’s one or two using SLS. Do we really want to be in that pickle?
This solution exists today! Docking in LEO has been happening since 1966 and today is done regularly and often automatically at the International Space Station. The answer is simple: save the $ 2 billion spent annually on SLS and put some of it into developing space refueling technology, lunar surface infrastructure, and water ice mining technologies; some can even be reallocated for climate change. It is a huge saving and we now have to take a step with the new administration.
To replace the above arguments with numbers, the SLS cost is pegged at approximately $ 2 billion per launch and the payload for LEO with Block 1 is 95 tons and Block 2 freight is 130 tons. Falcon Heavy, pegged at $ 125 million per launch with its semi-reusable option (the two side boosters restored and the core consumed) has a capacity of approximately 54 tons for LEO. Four flights of it can dump more than 200 tons in LEO, which is twice as much as one SLS block 1. So the estimated numbers are now $ 2 billion versus $ 500 million for twice the payload – an eight-fold advantage. Why shouldn’t we do this? Please note, you do not need to refuel, you only need to moor. And as the icing on this cake, we can also use some tanks on the top stair as habitat. Is this rocket science? No. Just common sense, perhaps with an innovative, out-of-the-box, bold thinking that NASA used to be known for.
Scheme. That we must “commit to a goal before no human lands on the moon this decade” was announced in 1961, and fulfilled despite those clumsy computers and initial achievements for nearly all of the successes. NASA taking longer for the Space Shuttle was already the beginning of another NASA than the one in the 1960s, which has just proven that it is now in a massive bureaucratic downturn, mainly thanks to the unfair political pressure exerted by some senators and such from companies. representing Mr. Thompson. There must be a limit to stretch this string unreasonably harder. It should break now. Yes, SpaceX was five years behind schedule for Falcon Heavy. But SLS is already in year ten since development was announced and hasn’t flown yet. No, those excuses just don’t wash anymore.
| This method, which is only possible with reusable booster rockets and not with SLS, not only creates the path to the Moon and Mars, but also to many other destinations in the solar system. |
Cost. Let’s take a look at the actual savings for taxpayers here in the example Mr. Thompson cites in his essay, where he compares Starship’s projected $ 2 million launch cost to the $ 331.8 million NASA just paid for a launch from Falcon Heavy. Indeed, the Starship cost quoted by SpaceX is absurdly low and may not come true. But even taking that number into account, NASA is being brought to the cleaners for $ 329.8 million more than it should ($ 331.8 million – $ 2 million), for the sake of discussion. But in the case of SLS, where each launch costs about $ 2 billion each, this is a higher number at about $ 1.67 billion, which will hit taxpayers. Which is a higher burden? It’s not just the ratio that counts. For taxpayers, this is the actual dollar amount.
Technology. The most impactful technology, possibly by far, developed by SpaceX is the sequence of the boostback maneuver, restarting the engine and landing on a droneship or returning to the launch site. This is what will save considerable sums making it unthinkable feasible. It changes the paradigm that helps not only this country but humanity as well. To make this light by comparing it to ‘the world’s largest welding machine’, like Forbes does in its assessment of new technology on SLS is to intentionally keep blinders on.
Justification. The method outlined above, which is only possible with reusable booster rockets and not SLS, not only creates the path to the Moon and Mars, but also to many other destinations in the solar system. Again, the common denominator is not to use SLS or other replaceable missile solutions, which are huge money pits. If we don’t think China will embrace this development while the US is once again a victim of political and big corporations, then we have another set of blinders on. It may not be all that this time. It could also be a security threat in terms of China moving much further ahead of us in the space arena, particularly cislunar space, if we don’t act quickly.
Thompson explains that “several companies on the SLS team, including the core phase contractor, contribute to my think tank.” On the other hand, no companies here – SpaceX, Blue Origin, Rocket Lab, or any other team – contributed to this opinion piece.
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