Landing Is Another Story
This morning, NASA’s Perseverance Rover launched en-route to the Red Planet. It is due to land there in February, and once there roll around to do tons of cool science. Much has been made about the rover’s advanced tech. What has received less attention is how routine getting to Mars has become…and how the landing is still kinda a big deal.
The Short Version of How To Get To Mars
- Leave Earth’s Ground Parts (TM Pending)
- Seems kinda intuitive – and really has been the only part of anything about space that people really seem to get amped about watching
- Chill in Earth Orbit For A Day Or So
- Technically this is less about just hanging out, and more about using Earth’s gravity as a slingshot to help you get to Mars faster.
- Point Towards Future Mars and Fire Engine
- Future Mars?
- Yep – as the image below shows, the planets are still moving while you in your little spaceship are trying to get to/from them. So, instead of just pointing yourself towards where Mars is right now (like you would do if you were going from Los Angeles to Colorado); you point yourself at where Mars WILL be.
- Future Mars?
- Seriously…that’s it…at this point if you did the math right and pointed yourself towards future Mars right you are going to get there. It is that easy.
Time To Stick The Landing
So you may have noticed I did not give any indication of what you do once you get to Mars or how to get from the space above Mars (where you are going to end up) to the ground. Which is an excellent point.
One option is to just run headlong into Mars in one fluid motion – in which case you should have a good set of braking rockets or a really impressive shield on the bottom of your lander…like this:
A second way is to have a separate lander craft that you can use to get down to the ground in. But again…going to need something to slow you down.
Perseverance plans to use a parachute like this one:
Curiosity used a sky-crane like this:
However you get from orbit to ground probably depends on whether you want to leave again. Since (so far) we have just been sending expendable robots we have been a little more lax on the whole getting back into orbit thing. This is going to end up changing for the first time next year (but that is a whole separate story).
All Of This Seems Pretty Standard – Why The Fuss
Ok – so yes. People have been parachuting for a while now, and have been falling from the sky just fine for even longer than that. So I get that it doesn’t seem like that big of a deal. And to be honest I think the difficulty is overhyped by risk adverse people. That said…it is actually a pretty complicated / difficult process for the following reasons:
- We don’t have a good model for Mars’ gravity.
- Yep you read that right. We actually don’t know EXACTLY how fast things fall on Mars.
- Allen Chen, who leads the Perseverance entry, descent and landing team for NASA’s Jet Propulsion Laboratory recently gave an interview to the New York Times where he pointed out that until Curiosity landed in 2012 we didn’t know that the gravity on Mars was uneven.
- We only have bad maps of Mars
- Ok so technically this isn’t completely true. We do have good orbital images. But we don’t have ground level views of things OR the sort of accurate terrain modeling available on Earth (I blame people wanting to look for life on Mars instead of the more important work of prepping it for an infestation of humans for that)
- Perseverance is adapting to that by using a pretty cool new automated landing technique
The Endy Parts
We will see here in February if all of the new landing tech works out – but at the end of the day the important thing to remember is: Whenever someone says it is difficult to get to Mars remind them that it is not at all. It is the landing that gets tricky. If you want to know more about the fun science of space, check out how gambling, drinking and even leading a protest is going to end up being a weird combo of similarly different.