Blog·Bob McDonald's Blog

Returning rockets launch a new era in space flight

The launch of SpaceX's new Falcon Heavy was a spectacular success, and Elon Musk's orbiting sports car made headlines. But the real breakthrough is in the successful reuse and landing of the rocket's side boosters.
SpaceX Falcon Heavy launches on its first flight (SpaceX)

Watching a rocket blast off from a launch pad and accelerate at unnatural speeds into space is a sight and sound to behold. But seeing rocket boosters return from the edge of space back to where they started, as I did in Florida on Tuesday, is astounding.

This week, the era of commercialized space flight took another giant leap forward with the launch of the Falcon Heavy, which sent a Tesla electric car into an orbit around the Sun that will take it out beyond Mars. It was a spectacular success for the first test flight of a new rocket. Seen from the ground, the flame shot out from the bottom of the big, white, triple-barrelled missile and became a brilliant orange sun in the blue sky, as the rocket rose majestically off the ground then arched out over the Atlantic ocean.

Falcon Heavy on its first test flight (SpaceX)
I've seen Space Shuttle launches, and they produce thick columns of smoke as they rise from the two solid rocket boosters burning aluminum perchlorate. The Falcon Heavy, burning a clean mixture of kerosene and liquid oxygen, left no trail at all. A brief vapour trail appeared when it passed through the sound barrier, but that too quickly disappeared.

Rockets of all sizes have been blasting off from the Kennedy Space Center, and adjacent Cape Canaveral Air Force Station since the 1950's, and almost all of them, except the Space Shuttles, let their first stage boosters fall into the Atlantic, never to be used again. If the ocean water off Cape Canaveral were clear, you would see literally thousands of old battered rocket boosters littering the ocean floor. That includes the first stages of the giant Saturn V rockets that sent astronauts to the moon.

That era of throwing away boosters after one use — a very expensive practice — is coming to an end as SpaceX, the company that built and launched Falcon Heavy, has pioneered bringing the boosters back and using them again.

SpaceX Falcon Heavy on the launch pad at the Kennedy Space Center before its first flight (SpaceX)
Rocket boosters really do the heavy lifting during launch. The three Falcon Heavy boosters sit under the second stage and the payload, and with a tremendous shove, they lift what is essentially a 20-storey building (224 feet or 68.4metres) straight up into the sky and accelerate it through the sound barrier up to 7,000 kilometres per hour. It takes so much fuel to do this Herculean feat, the tanks largely empty themselves after just two and a half minutes, while the rocket is still within sight of the launchpad.

To return, each Falcon booster saves some fuel for a controlled re-entry. Once released from the central core, they turn themselves around so they are flying backwards, re-light the engines to reverse their forward motion and essentially perform a giant U-turn in the sky, redirecting their fall back towards their starting point. They then fall like giant meteors, fire their engines once again for a few seconds on the way down to control their speed and direction, then freefall almost all the way to the ground until one last firing just before making a controlled touchdown.

Falcon Heavy side boosters landing at the Kennedy Space Center (SpaceX)
From the ground, we saw this several minutes after the rocket has blasted out of sight and the sound had faded into the distance. Suddenly, almost straight overhead, two bright orange lights appeared side by side in the blue sky. The duet had begun their landing ballet. The lights of the rocket engines shone like two new stars for about ten seconds, as the rockets did their deceleration burn. As the engines cut off, we lost sight of them, and there was nothing to see for another minute or so as they fell, unpowered, through the atmosphere. Finally, we spotted the two huge white cylinders falling incredibly fast, like giant lawn darts. Just before reaching the ground, the bright orange rocket tails erupted one last time and the big boosters, flying in perfect formation, gently settled themselves below a line of trees.

As the crowd cheered wildly at the astounding sight, four sonic booms — two from each booster — pounded our chests like a thunderous announcement saying, "We're Baaaack!" They were safe and sound. 

Unfortunately the same can't be said of the central core booster, which had a more difficult re-entry slammed into the ocean at 300 kilometres per hour right next to the SpaceX barge it was meant to land on.  It was the only blemish on a very successful test flight.

This incredible technical achievement is the way of the future, where rockets will be recycled to be used again rather than thrown away. In fact, the side boosters on this Falcon Heavy had already flown and landed before.

This should lower the cost of spaceflight both for the operators and customers. Falcon Heavy cost $90 million to fly.  It's closest competitor, the Delta Heavy, which cannot carry as much weight, costs in the vicinity of $300 million.  During the final years of the  Space Shuttle area, each shuttle launch cost more than $1 billion. SpaceX has shown that getting large rockets into space does not need to be so expensive.  

We are witnessing the handover of spaceflight from governments to the private sector, similar to the history of aviation. During World War II, governments spent huge amounts of money on large, heavy lift aircraft to carry bombs. Following the war, the same technology was adapted to create the commercial airline industry, which has lowered the cost of flying so today, almost anyone can take to the skies.

In the future, government agencies such as NASA or the Canadian Space Agency will become clients to these private space companies, along with the military, the communications industry and universities. They will be delivery trucks, carrying cargo and humans to space. Governments, hopefully through international cooperation, can then move on out to the frontier, taking risks the private sector can't afford, to explore deep space and develop new propulsion systems that will get us out there faster.

There was excitement in the air during the launch of Falcon Heavy, not just because a brand-new rocket, the most powerful in the world, actually flew successfully, but because we sensed we were on the cusp of a new era in spaceflight.

About the Author

Bob McDonald is the host of CBC Radio's award-winning weekly science program, Quirks & Quarks. He is also a science commentator for CBC News Network and CBC-TV's The National. He has received 12 honorary degrees and is an Officer of the Order of Canada.


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