Sunday, January 17, 2016

Rocket Reusability and Holy Grails

          By Glen Strom

Reusability is the holy grail of rocketry.

How often have you heard that? Lots, no doubt. Everybody from journalists to space analysts to space company presidents toss out that one when the talk gets around to reusing rockets. By now somebody has probably taught a parrot to squawk it.

A damaged SpaceX Falcon-9 rocket after a landing strut broke while making a hard landing on the drone ship "Just Read the Instructions." The rocket had just completed launching the US-European Jason-3 ocean monitoring satellite into orbit on January 17th, 2016. As outlined in the January 13th, 2016 Motherboard post, "Why SpaceX's 'Next Few Missions' Will Attempt to Land a Rocket at Sea," SpaceX will continue to attempt soft landings on drone-ships down-range from the launch pad because it requires less fuel than having the rocket fly back to the launch pad before landing. Photo c/o @elonmusk.

If you got a dollar every time a news article said that reusability is the holy grail of rocketry, you’d need a wheelbarrow to move the money (Keep in mind that Canada has a one dollar coin instead of a paper bill).

Jeff Bezos. Photo c/o EuropeanCEO.
For example, Blue Origin, the space company owned by billionaire Jeff Bezos, successfully landed their New Shepard rocket in November. In the November 24th, 2015 Seattle Times article, “Bezos says Blue Origin landing achieves ‘Holy Grail of rocketry’,” Mr. Bezos referred to reusability as “the holy grail of rocketry.” In all fairness, despite the headline, he didn’t say Blue Origin had achieved it, but that reusability would make make spaceflight less expensive. 

Recently SpaceX, the company owned by billionaire Elon Musk, landed a first stage booster on a landing pad, as seen in the December 21st, 2015 YouTube video, "Historic Landing of Falcon 9 First Stage at Landing Zone 1." In an earlier undated video interview that Mr. Musk did for the website, he also used the term holy grail in reference to rocket reusability.

Yes, they say that reusability will lower the cost of launching payloads by allowing launch companies to reuse the booster rather than building a new one from scratch.

Elon Musk. Photo c/o Reuters/Stephen Lam.
There’s only one teeny weeny problem with that idea: nobody has proven it yet.

Jean-Yves Le Gall, President of the French space agency Centre national d'études spatiales (CNES) said in a December 22, 2015 article at Space Daily, “SpaceX landing is a 'feat', but not a game-changer,” that the SpaceX landing was a “technological feat” but nothing more. He went on to say that questions about the cost of refurbishing a used rocket remain. He didn’t dismiss the possible advantages of reusability but he noted that it hadn’t been proven yet.

And please don’t point out that the writer said “game-changer.” One rant at a time.

Another perspective about the difficulties of reusability is outlined in a January 9, 2015 article at the website The, “Explainer: why reusable rockets are so hard to make.” The author, an expert in advanced propulsion systems at Southampton University in England, talks about the problems of balancing propellant, vehicle and payload mass. He talks about the importance of keeping the refurbishing costs down as well.

(A side note: he also used the term holy grail. It must be some kind of virus going around.)

Tory Bruno. Photo c/o ULA.
Salvatore “Tory” Bruno, the president of American launch company United Launch Alliance (ULA) and SpaceX’s main competitor, has talked about his company’s plans to incorporate reusability into their rockets.

In an April 13, 2015 article at Spaceflight Now, “ULA plans to introduce new rocket one piece at a time,” ULA will try a more conservative approach to reusability by recycling parts rather than the entire booster. Mr. Bruno also said that an internal ULA study showed it would take 15 flights before a refurbished booster would save money over single-use boosters.

Until a number of successful launches are made with a reusable booster and people get a chance to analyze the numbers, we won’t know if reusability really will bring down the cost of launching rockets, or if it’s just over-hyped wishful thinking.

Glen Strom.
In the mean time, maybe people can ease up on that holy grail squawk.

Right now the only holy grails are a religious symbol and a Monty Python movie.

Time will tell if there’s a third.

Glen Strom is a freelance writer and editor with a background in business and technical writing. Follow him on Twitter @stromspace for the latest on Canadian space stories.

1 comment:

  1. Well, calling it a grail isn't so bad. It holds a volatile liquid that gives you a boost! No so sure how holy a rocket can be. Maybe when it flies the pope to visit a lunar colony.
    From an economic perspective, I had a chat with a Space X representative at Toronto IAC back in 2014. I no longer remember the exact numbers, but the cost of a Falcon first stage is in the $millions. The cost of the fuel is in the tens, maybe hundreds, of $thousands. So there's the saving.
    However, as many rightly point out, it's not that simple. When the Atlas rocket in front of Ottawa's science and tech museum collapsed when it was depressurized it abundantly illustrated that these things are not designed for reuse. Reusability involves increased cost in design for durability and lost payload mass due to increased stage structural mass.
    All that said, Musk and Bezos have done the math so the economics must work on paper. Now they have to prove it (consistently) on the launch pad. Then I'm sure they will celebrate with a few filled grails of their own.


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