It Just Got Easier To Send People (And Extra Cans Of Tang) To Mars

One of the problems with sending people to Mars has been an issue of fuel. To store enough fuel for a return flight, you have to have a bigger spacecraft, which means more fuel, etc. Another issue with sending anything to Mars has been the narrow launch window, every 26 months for an optimal trajectory between Earth and Mars’ orbits. Any flight delays at all means you might have to scrap a launch for over two years.

The current method of landing something on Mars has a spacecraft racing to meet Mars in its orbit, then slamming on the brakes to end up in the planet’s gravitational field. This is called a Hohmann transfer, which uses up a significant amount of fuel. But Edward Belbruno and Francesco Topputo have written a paper theorizing the use of something called ballistic capture. And it may actually create a ton of leg room, should we ever send human astronauts to Mars.

They say a spacecraft launched anywhere near Mars’ orbit, running just slightly ahead of the planet, but flying a little bit slower, will have the planet catching up to it naturally, where it’ll scoop up the rocket to its gravitational field. This ballistic capture method is also called a low-energy transfer, and it may seem familiar because Belbruno came up with it while working for NASA in the 90s. They used it to send probes, like the GRAIL mission, around the Moon. Belbruno thought using the same idea to get a mission to Mars would be impossible, because Mars has a much higher velocity than the Moon, and getting something to roll in to Mars’ orbit in the same way wouldn’t work.

However, Boeing, who is the major contractor for NASA’s Space Launch System, was intrigued by the idea. According to James Green, director of NASA’s Planetary Science Division:

“What we want to do is leverage [ballistic capture] to put more mass on the ground. That’s the dream.” (source: Scientific American)

It would eliminate the need for precise deceleration of a spacecraft once it reaches Mars, which reduces both fuel consumption and the margin of error. The “slow and gentle” way also doesn’t require a heavy heat shield because you’re not slamming people in to Mars’ atmosphere in the hopes that the friction will slow everything down. Ballistic capture frees up 25% of a vessel’s payload from fuel, allowing any missions to the Red Planet to take extra equipment or supplies.

It also frees missions from that small 26-month launch window. We could send multiple spacecraft in a row, allowing more supplies and equipment to arrive on Mars right after any manned flights. We could send satellites out ahead of time, providing us with a communications network around Mars before we ever send anyone out there.

It’s not without its drawbacks, however. Landing a spacecraft slowly means adding time to a mission. Instead of a six month trip to get to Mars, it may take nine months or more. You’d also be flying too high above Mars to get anything productive done while you’re waiting to land. (This can be fixed by bringing a little bit of extra fuel along, though.)

As much as I hate the idea of just sending off a bunch of our junk to clutter the way to Mars, I don’t necessarily think an eight month road trip to another planet is unthinkable. NASA doesn’t either, which is why in 2015 Scott Kelly and Mikhail Kornienko will be sent up to the International Space Station for a year-long mission, to test the effects of microgravity for an extended period of time on human physiology.

Also you’d be flying to Mars, which seems a lot cooler to me than a two day trip to my in-law’s house, which I can verify often feels like six months.

via Blastr

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