SpaceX is a very interesting company because of what it is trying to do. They want to eventually put people on Mars and make bases there. However, to do that, they have some obstacles to overcome:
- Plan out how to go to Mars
- Get enough money to go to Mars
- Build rockets that will eventually go to Mars
- Get to Mars
Mars: The fourth planet in the Solar System, and is the next step from Earth after the Moon.
- Planning Out How to Get to Mars
Missions to Mars have been theorized since the earliest days of rocketry. SpaceX’s current plan is to launch a really big rocket and go to Mars. Once there, they plan to use materials found on Mars to make rocket fuel and other useful materials; but that’s a story for another day. In short:
- Getting Enough Money to go to Mars (and a shortened version of Elon Musk’s financial life)
Building huge rockets takes money. Where did Elon Musk get all of his money? He started off in the world of business with some help from his father. His company, X.com merged with PayPal in 2001, and was later bought by Ebay for $1.5 billion. Musk used this money to create SpaceX in 2002.
Great, now we have a man, a plan and a company. What now?
- Build Rockets that Will Eventually go to Mars
This is where we are now.Since SpaceX’s foundation, they have had 2 launch vehicles, and a couple of revisions to the latter:
The Falcon 1, shown on the very left of the diagram, was a small rocket used in the early years of SpaceX. It demonstrated to the world the commercial spaceflight would in fact be possible. The Falcon 1 was retired, and its potential payloads relabeled as secondary payloads for the bigger Falcon 9.
Secondary Payload: Something that “hitches a ride” from the rocket and tags along in addition to the bigger primary payload. The secondary payload is usually much lighter and tags along for the trip, which is why the light payloads that would’ve gone on the Falcon 1 were put onto the Falcon 9.
Now, for the bigger, badder brother, the Falcon 9. Since its first launch in 2010, the rocket has undergone 2 major changes, with the first making it taller and adding landing legs, and the second making it a bit taller and more powerful.
Why the landing legs, you say?
For the longest time, we have been launching rockets up and then letting the spent parts fall back to the ground, destroying them in the process. This costs a lot.
It’s like taking a flight on a 200+ million dollar Boeing 747 from Paris to New York, then throwing away the plane once you get there. This is why is costs so much to take stuff into space.
SpaceX (and Blue Origin) wanted to change the fact that spent boosters kept on falling into the ocean. An initial design concept from earlier in the decade shows a vision of a completely reusable rocket. (SpaceX later decided that it wasn’t worth recovering the second stage; once a rocket is at orbital speed, it’s going really fast sideways and needs to slow down a lot more than a rocket just going up.)
Fast forward to September 2013, where we see the first flight of Falcon 9 v1.1 (look at the diagram above for comparison). SpaceX tested the capabilities of the rocket by trying to land it in the ocean. Six experimental ocean landings (but with no recovery of the first stage) gave SpaceX the necessary information needed to move on to the next step: barge landings.
In January 2015, SpaceX attempted its first landing on a floating platform in the Atlantic Ocean, called Just Read the Instructions, an odd name, inspired by names of spaceships in the works of Iain M. Banks.
Needless to say, the first landing attempts were failures, even though they came close.
Note: The Falcon 9 first stage is huge. It is the size of a small building. You can probably see why it would be hard to steer the rocket onto a small barge floating in the ocean from space.
Furthermore, the first stage, even with one engine one, has a positive thrust-to-weight ratio (TWR), meaning that even if you try to turn down the engines to minimum throttle, the rocket would still go up from a standstill. (The Merlin 1D engines on the Falcon 9 cannot throttle below 70%.)
However, SpaceX succeeded finally in April 2016, landing a Falcon 9 on Of Course I Still Love You – their second landing droneship, whose name was also inspired by Iain Banks’ novels.
SpaceX has 3 main types of mission profiles (types of missions) which recover the first stage: Landing Pad Recovery/RTLS, LEO Droneship, and GTO Droneship.
Landing Pad Recovery/Return to Launch Site: The Falcon 9 booster goes up, does a loop around, heading back in the direction of the launchpad, then lands on the ground. This mission profile is used when the payload is very light, such as with small satellites and ISS resupply.
The boostback burn uses 3 of the 9 engines on the stage to send the booster back, and a bit upwards. The entry burn also uses 3 engines, and slows the first stage down when it hits the Earth’s atmosphere (otherwise the heat caused by the process would damage the rocket). Finally, the landing burn uses a single engine to slow the rocket down to land.
Low Earth Orbit Droneship: The first stage goes up, and performs a smaller boostback, then plunges downwards towards the droneship (barge) with an entry burn and a final landing burn. This profile is used when the payload is heavier or needs to go further, as having less of a boostback burn saves fuel.
Geostationary Transfer Orbit Droneship: This is by far the most risky one. Geostationary Transfer Orbit requires a significantly larger kick from the first stage, meaning it has less fuel to land with.
The first stage, after separating, completely skips the boostback and instead performs only an entry burn and landing burn. The landing burn is done with 3 engines instead of 1 and is a lot harder to time right. Nevertheless, SpaceX was able to execute this mission profile in May 2016 with the JCSAT-14 mission.
SpaceX had an accident in September 2016 which caused one of its rockets and a multi million dollar satellite to explode. SpaceX returned to flight in January of this year and is planning more missions in the future. They plan to bring the Falcon Heavy, essentially three Falcon 9s strapped to each other, into flight later this decade.
- Get to Mars
The future of space exploration is still uncertain. Many people are trying to get to Mars including SpaceX, Mars One, as well as NASA; but we are still not a point, both socially and technologically, where we can go there.SpaceX’s approach involves the ITS: the Interplanetary Transport System.
Announced last year, the ITS consists of a super-heavy-lifting rocket and a spacecraft on top. The booster on the bottom is intended to have 35 first stage engines. You read that right. The booster will have around three and a half time the thrust of the Saturn V (the rocket that took humans to the Moon). Oh, and it’s designed to be fully reusable. Go ahead and watch the video linked in point #1 if you haven’t already.
The spacecraft is no less absurd. It’s designed to carry 100 people to Mars and land there.
Both of these are powered by SpaceX’s new Raptor rocket engine. The Raptor was designed to use methane (natural gas) and oxygen as fuel. This means that it can refuel wherever there is a sources of water and carbon dioxyde (like Mars).
The ITS is currently in development, but will likely fly in this half of the century.
In conclusion, SpaceX has done, and will be doing a lot of really cool things. Getting humans to Mars will be a monumental achievement for the world when it happens, and I’m personally looking forward to it.
If there’s anything I missed that you want me to cover, leave a comment below or on this page. Otherwise, thanks for reading!
Stay tuned and stay sciency,
P.S. My next topic will likely be on how rocket engines work.