Big is better…

When it comes to rocket engines the more power you have the more stuff you can put into space – roughly. So with US President Donald Trump’s signing of the Space Policy Directive 1 a few days ago, I got to thinking about the different launch systems that are around and how they compare to the mighty Saturn V and all of the stuff bolted to the shuttles as there were some serious rocket engines in those programmes. This reminded me that NASA has been working on the Space Launch System for quite some time and though it hasn’t attracted the hype that surrounds Blue Origin and SpaceX, it is still very impressive. The progress on the SLS seems to be going well with all of the components coming together for the EM-1 test, hopefully next year.

NASA have done a fair bit of work modernising the RS-25 rocket engines with new engine controllers and a 3D printed shock absorber (it has a much more technical name). The RS-25 engines were built for the Shuttle programme which had three of them on the aft of the shuttle. After each flight the engines were taken off and refurbished before being stored for future flights. The reliability of the engines was very high, hence the continued enthusiasm to use them. Though they’re not cheap at around $40 million a piece when they were built (not sure what the second hand price is). The RS-25 is going to be used on the Space Launch System (SLS) with four of them generating around 2,000,000 pounds of thrust. The other 6,000,000 pounds of thrust will come from the boosters.

An RS-25 being tested (NASA)

That’s a huge amount of power and it’s needed to get the Orion space craft off the ground and hurtling towards the Moon (and eventually Mars). The next big test will be to fire all four engines at the same time. To help RS-25s to propel the SLS skyward there will be large rocket boosters. These will generate 75% of the power needed for the first 2 minutes of flight and make the SLS the most powerful rocket in the world – this is one serious heavy lifter.

The exit cones on two of the SLS boosters (NASA)

Sitting atop all of that power will be the crew module, the Orion spacecraft. This is also going through a bunch of testing. Recently there was a high speed parachute test where the parachute to slow the spacecraft on reentry was deployed while the spacecraft was travelling faster than the speed of sound. The below picture was a parachute test of the whole system earlier in the year.

Orion landing under parachute (NASA)

This is a really exciting time and over the next few years we’re going to see some amazing developments in the variety of launch systems and the involvement of private companies. For those of us too young to have had the opportunity to witness the launches of Saturn V rockets we will get the chance to see something equally as impressive in the coming years – I think it’s time to update the passport!