ROCKET SCIENCE
Huge rockets make their debut:
Missions to the Moon and Mars may soon become a matter of routine, as four huge rockets make their debut over the next year to achieve tasks far more scientific than merely lifting bored billionaires into Space...
The roar is deafening as NASA activates the engines of the huge Space Launch System rocket. Particles of metallic zircon flash like sparklers in the air around the blazing rocket nozzles. “It was like an earthquake,” said NASA Administrator Jim Bridenstine during a press conference after the test on 16 January 2021, during which the rocket engines were strained to their limits.
The Space Launch System’s engines are 15% more powerful than those of the biggest rocket that ever flew, the Saturn V moon rocket (see previous issue). According to the plan, the huge new rocket will lift off for the first time in November 2021.
And the SLS is only one of four major new rockets that will soon make their debut. If all goes well, SpaceX’s Starship may orbit Earth before this issue of Science Illustrated reaches your hands. Blue Origin plans for its New Glenn rocket to do the same within the next year. And in late 2021, the new Vulcan Centaur rocket should send a landing module to the Moon.
The four rockets mark an exciting new era for aerospace, and an explosion in the number of opportunities to launch anything
from robots to space tourists and astronauts into an orbit around Earth, to the Moon – and all the way to Mars.
Beat Apollo rocket records
None of the new rockets would have been possible without German rocket engineer Wernher von Braun, who helped develop the Nazi V-2 rocket. Last issue we told the story of how Von Braun came to the US in 1945, the Americans later putting him in charge of the rocket programme that subsequently won the space race against the Soviet Union with the biggest rocket ever: Saturn V.
Its force of 34.5 millon newtons, which sent 24 Apollo astronauts to the Moon, has not been outperformed since.
According to von Braun, the natural next step in a space programme was to design a reusable spacecraft – and that led to the space shuttle programme, which carried out 135 missions and was key to the construction of the ISS space station which orbits Earth at an altitude of around 400km.
But we must tackle far longer distances if we are to travel to the Moon again – and to Mars. The Moon is 384,000 kilometres away; Mars more than 55 million kilometres. So a new generation of rockets is preparing for
take-off, ready to deliver more power, and more space for cargo and crew.
The engineers at four companies and agencies are ready – or nearly so – to introduce their new huge rockets. There is United Launch Alliance, which has made rockets for the famous rover missions to Mars. Blue Origin was founded by Amazon billionaire Jeff Bezos. SpaceX was established by Tesla billionaire Elon Musk. And last, but certainly not least, there is NASA, the agency that launched Saturn V.
New moon rocket for a new era
Since man first set foot on the Moon some 52 years ago, no rocket has outcompeted the Saturn V. That’s now about to change. The Space Launch System will be more powerful than Saturn V, though the new rocket is indebted to Wernher von Braun, very much based on technologies that were developed for the space shuttles. The main engines are known as RS-25 liquid-fuel cryogenic rocket engines, and there used to be three of them at the back of the space shuttles. At the bottom of the SLS, you will find four RS-25s, updated now to include new 3D-printed metal parts, and with their efficiency raised to 109% of the originals.
On the sides of the main rocket are solidstate rockets, also repurposed from the space shuttle programme and supplied with 25% more fuel. The SLS will come in six different versions, growing bigger according to the extent of the missions. The first
14 jumbo jets would be required to provide the force of two SLS solid-state rockets.
version, known as Block 1, can lift 70 tonnes to a low Earth orbit, while the most recent version, Block 2, can lift 130 tonnes.
The plan is that from 2028 the Space Launch System will allow astronauts to permanently orbit the Moon or to live on bases on the surface. Over nine missions, the huge rocket is to carry the bulk of the building materials required for a station and base – and astronauts, of course – on the Moon.
The Moon will also be the destination when Vulcan Centaur is launched for the first time. This rocket is a far larger successor to the Atlas V, which is most famous for sending the Perseverance rover to Mars. Before the end of 2021, Vulcan Centaur is due to send the Peregrine landing module to the surface of the Moon.
The 62-metre-high Vulcan Centaur can lift about 27 tonnes to a low Earth orbit – Atlas V could lift a maximum of 20 tonnes.
Again Vulcan Centaur comes in different versions — here four, with 0, 2, 4, or 6 solidstate rockets mounted to the rocket’s central cylinder. The Vulcan Centaur can thereby be adjusted for a series of different missions.
The rocket is also designed so that many components can be retrieved and reused. This is true for the engines, named BE-4, which consume a mixture of liquid oxygen and natural gas, leaving the engines in a far better condition than do dirtier traditional rocket fuels such as kerosene.
BE-4 was developed by Blue Origin for their new New Glenn project (below). And
whereas Vulcan Centaur’s engines can be reused, the entire central section of New Glenn can be launched again. The engineers behind New Glenn incorporated a key element of the new aerospace era: recycling.
The new paradigm of reusing rockets or parts of rockets saves valuable time, materials and work, allowing more regular flights – an ongoing service to space and back.
Reusable rockets pave the way
In the old days, rockets were launched, then fell back through the atmosphere when they had been emptied of fuel. Despite the vast cost of such one-off rocket usage, no way to reliably recover and re-use this ‘space junk’ had been devised. That will change with the new generation of rockets, with major sections ble to control their own landings after completing their lifting duties.
This is a central feature of the New Glenn rocket, which will be used initially mainly to launch satellites into space, but also people at a later point in time. The rocket can be reused 25 times or more. Its lower stage is equipped with fins which can steer it safely down after it disengages, while the rocket’s upper stages continue towards space. Seven main engines slow down the rocket as it
approaches Earth’s surface, while six hydraulic landing legs unfold.
The New Glenn will be able to lift 45 tonnes into an orbit around Earth. At the top of the 95-metre-high rocket is a cargo compartment with a diameter of 7 metres and a total volume more than twice that of any currently active rocket.
While the initial New Glenn rockets are designed to carry freight, Space X’s Starship rocket is designed to carry a more ambitious load: people. And not just the three-person crew which sat atop those Saturn V rocketrs of the classic era. According to Space X, Starship will be able to seat 100 people, with the construction of a much larger cabin than has been used in any other rocket.
Both the old Saturn V lunar missions and the new SLS missions involve a crew positioned in the small nose of the rocket. In Starship, the manned section will comprise almost half of the total height, with the crew in an extended cabin mounted on top of a 70-metre-high booster rocket, for a total height of 120 metres. The entire rocket will be able to lift more than 100 tonnes into an orbit around Earth, and SpaceX’s plan is that is will be a fully reusable rocket able to send astronauts to the Moon and, in the course of time, to be used as a means of transport to other planets in the Solar System – notably, of course, Mars.
One different feature of Starship is the material from which it is constructed. It uses steel, rather than aluminium, making the craft relatively cheap and also more resistant to the low temperatures of space.
As for its re-use, Starship is designed to land again following a ‘belly-flop’ procedure as it passes down through the atmosphere, then using flexible fins for a spectacular flipping manoeuvre close to the surface, landing vertically, ready for the next launch.
With such complete recycling meaning that SpaceX won’t need to build a new Starship for every launch, a more regular space tourist service could be undertaken. On the first test mission in 2023, SpaceX plans to send Japanese billionaire Yusaku Maezawa and up to eight other space tourists on a week-long space mission, when Starship will fly past the Moon.
Starship is also intended for a regular service all the way to Mars, which will be possible through a system of refuelling in space. An unmanned Starship loaded with fuel will first enter orbit around Earth, then a manned Starship will follow. The two craft will dock with each other for the fuel to be transferred to the manned craft to replace fuel expended during its launch – the most fuel-intense part of a mission is the trip from Earth’s surface into orbit. With a full tank the manned Starship can then embark on a much longer mission into space, while the Starship ‘tanker’ returns to Earth again, ready for re-use.
Elon Musk hopes that up to 1000 Starships could be refuelled and ready in a holding position in orbit, waiting for the
80 days will be Starship's travel time to Mars.
optimal time to launch the whole convoy of spaceships towards Mars. The best such slots occur every 26 months.
This idea of regular service operations characterises the new aerospace era that will begin with the four new large rockets. They are bigger and stronger than previous rockets, and they are not limited to single missions or specific roles. Each of them is designed to carry out a wide variety of tasks, and they are made of reusable parts, enabling more rockets to be launched at ever more regular intervals. We are approaching a future in which a big rocket will always be ready to go on the launch pad.
Five decades ago, the Apollo missions had single-use Saturn V rockets and flew relatively rarely. The new missions will launch more often, and will gradually move our attention from the Moon-focused Apollo era to new destinations. With NASA, the United Launch Alliance, Blue Origin and SpaceX all looking deeper into the Solar System – to Mars and beyond – we’re on the launch pad of a new highway into space, and a new age of human-observed discovery.