Should NASA’s next mission be to an asteroid or a Martian moon?

[jimmy olsen]

I vote Martian Moon!

http://blog.chron.com/sciguy/2015/04/should-nasas-next-mission-be-to-an-asteroid-or-a-martian-moon/

Should NASA's next mission be to an asteroid or a Martian moon?

Posted on April 13, 2015  |  By Eric Berger   

On Friday NASA's Advisory Council formally suggested that the space agency cancel its Asteroid Redirect Mission and replace it with a mission to the orbit of Mars. This, it should be noted, is an uncrewed mission meant to test out NASA's new, promising solar electric propulsion (SEP) technology.

NASA is under no obligation to heed its advisory council's finding, and may well ignore the group. However NASA has received a lot of criticism from Congress and the scientific community about the asteroid mission because it does not appear to show much progress on getting humans closer to Mars. Now that its own advisory council has formally come out against NASA's asteroid plan it will be more difficult to sell the idea to Congress, which must approve funding for it.

So which is the better option? Here's a look at some of the pros and cons of changing uncrewed spacecraft's destination to Mars — and possibly grabbing a small rock off the surface of the Martian moon Phobos or Deimos.

PROS

Pathway to Mars: This is probably the key reason NASA's advisors recommended this change. An uncrewed mission to the Mars orbit is much more clearly on the pathway to Mars than sending the same spacecraft into deep space to grab a small rock of some asteroid. "If this technology is designed to go to Mars and back, let's send it to Mars and back," said Steve Squyres, chairman of the advisory committee.

Broaden support: Some scientists do support the asteroid mission, but many do not. Richard Binzel, a noted asteroid expert at the Massachusetts Institute of Technology, has been one of the mission's chief critics. The idea of plucking a boulder off the surface of Phobos, instead of an asteroid, has some merit he told me. "Redirecting SEP to be truly relevant to Mars has been the underpinning of all critiques," he said. "The NAC finding finally hits this head on."

More realistic test: NASA is devising solar propulsion to get cargo to Mars. Because it runs on solar power this method of propulsion uses far less fuel than chemical rockets, only about 10 percent as much. That's a huge cost savings, and important if you're going to get all of the supplies to Mars you'll need for a human mission. Solar propulsion is slower, of course, so you'd only use it for cargo, but that's OK. And if you're going to use it to send cargo to Mars, sending this initial mission to Mars provides an optimal test bed.

Martian sample: The advisory committee only recommended a "Martian orbit" for this mission — they wanted to give NASA flexibility in planning — but many members wanted a sample return from Phobos. This would be useful because many scenarios for human missions to Mars contemplate landings on the Martian moons, and so having a sample from one would prove useful for those purposes.

CONS

Time and money: Sending a SEP spacecraft to Mars orbit, and one of the moons, will probably take a few years longer than retrieving a boulder from an asteroid, as in the proposed asteroid mission. Any kind of delay is not an easy pill for an agency already struggling to show America and the Congress that it is making substantial progress toward exploring deep space. Moreover a Martian foray would probably cost more, although it is not clear how much.

Size of return: Whereas a SEP spacecraft would be able to pull about a 70-ton rock from the surface of an asteroid and return it to the vicinity of the moon, it would likely only be able to get about 5 tons, or less, of material from Phobos due to its slightly higher gravity well.

Orion: One of the things NASA hopes to do in the mid-2020s is use its new Orion spacecraft and SLS rocket to send astronauts somewhere. A small asteroid near the moon, captured and returned by the SEP spacecraft, would represent a new "destination" for Orion. If it takes longer to get a rock from Phobos, and the rock is smaller, what do Orion and its astronauts do in the meantime?

Politics: President Obama directed NASA to have its astronauts visit an asteroid by 2025. Under its latest version of the asteroid mission NASA still met this mandate. Many planetary scientists believe Phobos is an asteroid captured by Mars, so a chunk of that moon still might be considered an asteroid. But could NASA get the rock back to the moon by 2025 for astronauts to visit it then? That's questionable.

CONCLUSION

There are both pros and cons for substituting a Martian fly-by using its solar electric propulsion technology for the asteroid mission.

In the end, however, the big challenge for NASA is to convince Americans, Congress and perhaps most importantly, the next President that is has a credible pathway to Mars. For this reason I think swapping Mars orbit for the asteroid mission to prove the SEP technology is an idea that will carry a lot of interest in the spaceflight community. This, in turn, will bring some pressure to bear on the space agency.

Whether that's enough to change the destination will be one of the fascinating space policy stories to follow in 2015.

[Eddie Teach]

I vote Martian Moon!

What a terrifying idea.

[KRonn]

I picked a Martian moon but would rather a trip to Mars.

[lustindarkness]

Mars or The Moon, not a martian moon.

[Ed Anger]

Shoot Tim into the Sun.

[dps]

Shoot Tim into the Sun.

What, and taint sunshine? 

[jimmy olsen]

I picked a Martian moon but would rather a trip to Mars.

Supposed to be a bit of a test run, kind of like the missions before Apollo.

[The Brain]

Martian Moon? Is that a fag dog-eater?

[Archy]

land as a first a man on the sun

[Berkut]

You know, bitching about Tim is all fine and such, but isn't it kind of old?

Does the fact that a thread like this is 100% consumed with people re-trolling the "OMG TIMTIMTIM" thing for the 500th time really actually more interesting than the actual content?

I have to presume so, since every single thread like this that might actually be interesting is totally just about trolling Tim instead.

[The Brain]

I agree with Berkut that people complain too much.