Author Topic: An asteroid mission may be harder than going to Mars  (Read 6024 times)

Offline CNYMike

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I found this article on Yahoo:

http://news.yahoo.com/asteroids-may-tougher-target-mars-manned-missions-115330035.html

Maybe the Moon should have been kept on the table!  At least we can get there.
« Last Edit: 02/07/2013 02:28 AM by Chris Bergin »
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Offline Robotbeat

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Fluff piece. There are lots of asteroid targets to pick from, THAT is the real reason none has been picked. It's like complaining Kennedy didn't map out all the landing sites for Apollo during his famous speech.
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Offline kevin-rf

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This has been discussed before, it is hard to find an asteroid that do not require an excessive (compared to Mars) Delta V to do more than a flyby. There are not many decent sized asteroids to chose from.
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Offline Robotbeat

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This has been discussed before, it is hard to find an asteroid that do not require an excessive (compared to Mars) Delta V to do more than a flyby. There are not many decent sized asteroids to chose from.
False, there are plenty.

http://neo.jpl.nasa.gov/cgi-bin/nhats?dv=9&dur=360&stay=8&launch=2015-2040&H=30&occ=7&sort=n_via_traj&sdir=DESC&action=Display+Table#top
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Offline Ben the Space Brit

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This has been discussed before, it is hard to find an asteroid that do not require an excessive (compared to Mars) Delta V to do more than a flyby. There are not many decent sized asteroids to chose from.

False, there are plenty.

Apparently, people don't believe you.
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Offline Robotbeat

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This has been discussed before, it is hard to find an asteroid that do not require an excessive (compared to Mars) Delta V to do more than a flyby. There are not many decent sized asteroids to chose from.

False, there are plenty.

Apparently, people don't believe you.
Talk to JPL, then.
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Offline Robotbeat

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BTW, did you ever bother clicking that link and looking at the different options available?
Chris  Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Offline CNYMike

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This has been discussed before, it is hard to find an asteroid that do not require an excessive (compared to Mars) Delta V to do more than a flyby. There are not many decent sized asteroids to chose from.
False, there are plenty.

http://neo.jpl.nasa.gov/cgi-bin/nhats?dv=9&dur=360&stay=8&launch=2015-2040&H=30&occ=7&sort=n_via_traj&sdir=DESC&action=Display+Table#top

And the technical problem may not be insurmountable. I see your point.
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Offline QuantumG

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And that's the "naturally occurring" options. If we start modifying the orbits of asteroids (which we need to learn to do for planetary protection anyway) then we can make targets that are even more favorable for exploration by humans.
« Last Edit: 02/06/2013 10:18 PM by QuantumG »
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Offline Danderman

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And that's the "naturally occurring" options. If we start modifying the orbits of asteroids (which we need to learn to do for planetary protection anyway) then we can make targets that are even more favorable for exploration by humans.

In that future where we can move asteroids around, delta-V will be least of our concerns.

Offline QuantumG

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And that's the "naturally occurring" options. If we start modifying the orbits of asteroids (which we need to learn to do for planetary protection anyway) then we can make targets that are even more favorable for exploration by humans.

In that future where we can move asteroids around, delta-V will be least of our concerns.

We can do it now, we just don't have the will.
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Offline Danderman

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The larger problem is that some "good" targets don't come around much, so if you miss the launch window, you may have to wait 10 years for the object to come around again.

Also, trajectories that can approach an asteroid are far different from trajectories that can approach an asteroid at relatively low delta-V, just like it's relatively easy to fly by the Moon, but really hard to get your relative delta-V down to zero, compared with the lunar surface.

Last note: object 1991 VG is rumored to be an Apollo launch vehicle upper stage.

« Last Edit: 02/06/2013 10:28 PM by Danderman »

Offline Robotbeat

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But most of those concerns are addressed by the sheer number of possible targets in the link I posted.
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Offline collectSPACE

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But most of those concerns are addressed by the sheer number of possible targets in the link I posted.

The chart was designed "to be highly inclusive" when many of the targets identified may not be a possibility for multiple reasons.

For example, the chart doesn't seem to take into consideration the type of asteroid. Rubble piles may be too unsteady for a human mission, especially a first mission, as opposed to solid bodies.

The chart includes targets with an Earth departure date of 2015 far sooner than any spacecraft will be ready and extends through 2040 far later than anyone wants to wait for a first mission.

The chart also includes targets that would require a mission duration as long as 15 months, which may be restrictive given logistical constraints (carrying food for 15 months is just one consideration). The ideal mission, says those working the mission planning at Johnson Space Center, is 90 days.

Mike Wall's article isn't intended to be a technical paper; it is a news summary for the general public. That doesn't mean it isn't backed by facts. The contention that finding a suitable asteroid target is a concern has been voiced by more than just the National Research Council. For example, my own interview last March:

"The real problem with these near-Earth asteroids is Mother Nature is not really cooperating with us," John Gruener, a planetary scientist at Johnson Space Center, said. "We haven't found any that are close enough and are low enough inclination."

"We would like to find near-Earth asteroids that are in the ecliptic plane and that come in at slow enough velocities so that our [spacecraft] velocities don't have to be amped up to meet it. But we haven't found one of those yet," he said.
« Last Edit: 02/06/2013 11:57 PM by collectSPACE »

Offline Patchouli

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This has been discussed before, it is hard to find an asteroid that do not require an excessive (compared to Mars) Delta V to do more than a flyby. There are not many decent sized asteroids to chose from.

Delta V is only one aspect of mission difficultly.
Mission duration and the need to land on a large body also can make a mission much more massive and difficult.

An NEO mission generally would be much less mass then a Mars mission as it's much shorter in duration with most under 180 days and do not require a lander, MAV, or Hab.

Being less massive makes the delta V requirements less of an issue.
« Last Edit: 02/07/2013 12:40 AM by Patchouli »

Offline Blackstar

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First, allow me to sigh loudly at this whole thing.

SIGH

(There, I feel better now.)

The article is highly misleading, but if you read it closely, you can see how the author might have gone off-track. In short, he is reporting about something that Marcia Smith said during a telecon discussion last week about something that Bill Gerstenmaier said to a committee in July 2012 OVER SIX MONTHS AGO. If you stop and think about it a bit, you might ask why the reporter didn't simply call up Gerstenmaier himself and ask him. Why rely upon a second-hand source? (Cause he's lazy, that's why.)

Now I happened to be on that telecon, but I don't remember Ms. Smith's exact words. It is possible that she misspoke. It is also possible that the reporter misunderstood her. And although I don't know Mike Wall, I do think that he should not have based his article upon that telecon. The FISO telecons don't exist so that reporters or bloggers can write articles based upon them, and sloppy journalism like this is the kind of thing that can result in them ending. It's just not very professional journalism. If he wanted a story, he should have called the people on the phone himself and asked them questions. But that's another issue.

My guess is that Ms. Smith misspoke and the reporter never called her to clarify. The reporter refers to Gerstenmaier speaking to the NRC committee. I happened to be there when he did so (I was the study director for that report) and what I remember him saying was not that an asteroid mission is harder than Mars, but that an asteroid mission is harder than NASA initially expected it to be. Had the reporter done his job, he could have clarified this.

Bottom line, it's a crappy article.

Offline Blackstar

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There are lots of asteroid targets to pick from, THAT is the real reason none has been picked.

This is absolutely wrong.

Once you factor in all of the requirements such as travel time, approximate date (2025), size, rotation, you come up with essentially ONE viable asteroid target. Everybody involved in the issue will tell you that what is required to do the mission is a survey telescope to identify more targets. And nobody is building that survey telescope.
« Last Edit: 02/07/2013 01:02 AM by Blackstar »

Offline Prober

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I found this article on Yahoo:

http://news.yahoo.com/asteroids-may-tougher-target-mars-manned-missions-115330035.html

Maybe the Moon should have been kept on the table!  At least we can get there.


all part of the plan.   This is just the start of its too hard and soon will become too expensive.   Cancel the whole program.
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Offline QuantumG

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Once you factor in all of the requirements such as travel time, approximate date (2025), size, rotation, you come up with essentially ONE viable asteroid target. Everybody involved in the issue will tell you that what is required to do the mission is a survey telescope to identify more targets. And nobody is building that survey telescope.

Wait, are you suggesting that if you keep adding criteria to a filter it will reduce the number of result? Who knew!
Jeff Bezos has billions to spend on rockets and can go at whatever pace he likes! Wow! What pace is he going at? Well... have you heard of Zeno's paradox?

Offline Robotbeat

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There are lots of asteroid targets to pick from, THAT is the real reason none has been picked.

This is absolutely wrong.

Once you factor in all of the requirements such as travel time, approximate date (2025), size, rotation, you come up with essentially ONE viable asteroid target. Everybody involved in the issue will tell you that what is required to do the mission is a survey telescope to identify more targets. And nobody is building that survey telescope.
Yes, if you constrain yourself to the largest asteroid in your search results, obviously you'll only find one.

That's just a snarky way of me saying you can broaden the search parameters somewhat and have plenty of targets to choose from. If you're picky, you're picky and likely to have to settle with just a handful (or one).

That said, I agree perhaps the biggest return-on-investment we could make right now is a really good survey telescope. (This is also what Apollo did... They invested in mapping the Moon. And besides, surveying all the NEAs is perhaps the clearest, most direct, and least expensive way for NASA to contribute to the continued health, safety, prosperity, and survival of humanity.)
« Last Edit: 02/07/2013 02:12 AM by Robotbeat »
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