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#180
by
robertross
on 20 Jan, 2010 20:07
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It still doesn't answer Bill's original question of 'quantifying' it, as in a 'dollar figure'. That is why I used my beaseball game reference. How do you quantify 'pleasure' or 'entertainment', because there is a component factor in spaceflight which cannot be measured (the wow factor), and it is significantly greater for manned spaceflight than unmanned, and it depends on the roles.
Personally, I'm of the opinion that pure science is impossible to value: some of it is negative in cost (takes resources that could have gone elsewhere) to so valuable it transcends notions of money. It would be like trying to determine the value of the research that led to the transistor or the laser: theoretically, you can add the sum of all products that use them, but you would still be missing some of the value these devices give our modern lives.
Same thoughts here.
We are still learning. Let's hope we never stop learning.
I think an asteroid mission is cool, I just hope it doesn't take precedence, or overrides many of the other goals in manned & unmanned spaceflight.
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#181
by
robertross
on 23 Jan, 2010 21:56
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Just to add a link of a recent report released by the National Academy of Sciences on detecting NEOs.
http://www8.nationalacademies.org/onpinews/newsitem.aspx?RecordID=12842(Brief snip):
Date: Jan. 22, 2010
Contacts: Sara Frueh, Media Relations Officer
Alison Burnette, Media Relations Assistant
Office of News and Public Information
202-334-2138; e-mail <
[email protected]>
FOR IMMEDIATE RELEASE
Report Examines Options for Detecting and Countering Near-Earth Objects
WASHINGTON -- A new report from the National Research Council lays out options NASA could follow to detect more near-Earth objects (NEOs) – asteroids and comets that could pose a hazard if they cross Earth's orbit. The report says the $4 million the U.S. spends annually to search for NEOs is insufficient to meet a congressionally mandated requirement to detect NEOs that could threaten Earth.
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#182
by
Chris Bergin
on 16 Apr, 2010 10:42
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Bumpity bump.
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#183
by
Garrett
on 16 Apr, 2010 10:49
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I haven't got around to reading through this thread yet, nor the main article it refers to, but here are my questions anyways.
In light of Obama's speech, and his explicit statement regarding sending astronauts to near Earth asteroids, what do people here think?
As asteroid orbits are unique, I would imagine such missions would vary greatly in terms of total mission duration and the intermediate steps (going, staying and coming back) depending on the asteroid chosen. There are probably both advantages and disadvantages to this, but what are they? And is going to an asteroid really a stepping stone to Mars? And can asteroid missions inspire the younger generation of Americans as much as a mission to Mars?
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#184
by
Ben the Space Brit
on 16 Apr, 2010 11:03
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IIRC, the 2025 DRM mission that Chris referred to in the article related to this thread called for an extreme high-dV hyperbolic transfer orbit and then to follow the NEO to Earth before dropping off in an Orion for a quick descet. I'm sure that I'll be corrected if I've got anything wrong.
That said, am I the only one who has noticed that targets suitable for this mission profile tend to be smaller than the likely mission spacecraft (in the 10-20m long axis bracket)? There is probably a good reason for this - Earth and the Moon have likely already 'swept up' any significant-sized objects in their vicinity. The big boys like the Amors, Apollos and the like (including Eros) are further away and would likely need a specialised MTV design to access rather than the proposed dual-Orion.
If I were asked to name a target, it would be the Earth-Moon co-orbital asteroids that have recently been discovered in 'crescent moon' oscilating positions relative to Earth.
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#185
by
Chris Bergin
on 16 Apr, 2010 13:45
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Come to think about it, are they also using the Flexible Path Mars approach too? Mars orbit, Phobos, Mars landing?
Might have to bump that as well!
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#186
by
Ben the Space Brit
on 16 Apr, 2010 15:59
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Come to think about it, are they also using the Flexible Path Mars approach too? Mars orbit, Phobos, Mars landing?
I think it is safe to say that Obama's speech assumed a Mars-centric flexible path strategy.
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#187
by
robertross
on 16 Apr, 2010 17:51
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Come to think about it, are they also using the Flexible Path Mars approach too? Mars orbit, Phobos, Mars landing?
I think it is safe to say that Obama's speech assumed a Mars-centric flexible path strategy.
I would be in agreement with that.
What is very important from his speech was the post-Mars orbit mission (IE: landing). "...sometime after that" as he said. Smart man, as that's the hardest one of all.
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#188
by
anonymous
on 17 Apr, 2010 22:27
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I'd been thinking along the same lines as Ben. The conclusion I drew from the report was that a dual-Orion architecture with a crew of two is ridiculously limited. The smallness of the asteroids that can be reached that way is a problem. 1999AO10 is the only one that's big enough (50-100m) that an astronaut going out to 'explore' it wouldn't look incredibly silly on television. It seems to me that you can visit 1999AO10 once, but then you need a mission module that can support longer missions to asteroids that are more substantial.
What is very important from his speech was the post-Mars orbit mission (IE: landing). "...sometime after that" as he said. Smart man, as that's the hardest one of all.
He then said "And I expect to be around to see it." That implies by 2050 or so.
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#189
by
the_roche_lobe
on 17 Apr, 2010 22:52
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Well there are two large-ish, interesting and eminently explorable asteroids in Mars orbit, plus some 'bonus science' and great shots for the folks at home on that 6k diameter rock that's filling the view of the IMAX/HD cameras
Of course dual Orions aren't going to cut it for that mission either...a good sized mission module is needed (Bigelow? ATV derived? ISS derived?) and what about low-g exploration mobility on the moons themselves - we aren't talking about an Orion actually 'docking' with a 20k diameter moon are we??
P
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#190
by
robertross
on 17 Apr, 2010 23:00
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Well there are two large-ish, interesting and eminently explorable asteroids in Mars orbit, plus some 'bonus science' and great shots for the folks at home on that 6k diameter rock that's filling the view of the IMAX/HD cameras
Of course dual Orions aren't going to cut it for that mission either...a good sized mission module is needed (Bigelow? ATV derived? ISS derived?) and what about low-g exploration mobility on the moons themselves - we aren't talking about an Orion actually 'docking' with a 20k diameter moon are we??
P
I suspect we will have the culmination of a number of vehicles to make this happen.
1. Dual Orion setup for redundancy (perhaps one encapsulated and kept in a PLF for better protection)
2. A hab module for long duration, including excersise equipment and storage modules, perhaps all based on Bigelows.
3. Propulsion module with sufficient power (say RTG) for a VASIMR module, probably triple redundant. The transit times determines #4
4. Artificial Gravity (AG) requirement, if the journey exceeds ~6 months total.
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#191
by
Orbiter
on 18 Apr, 2010 00:13
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(please don't turn this into a flame argument)
Now that the president has announced his new vision for space exploration (again don't discuss here) and it has an Asteroid mission in the works for 2025 right?
Well, I was wondering what Asteroid could we possibly go to? I was thinking, because Apophis is going to come near Earth in 2029 we could visit that in 2025-26, to possibly learn ways to deflect Asteroids coming towards Earth.
What are some options on way to get there? I'm not talking about spacecraft, I'm talking about propulsion and trajectory. What propulsion would be cheapest? Ion propulsion, Nucular, or just strait up liquid fuel? And what are some of the quickest ways we could get a spacecraft to there, flyby the moon to gain speed on the way there? On orbit refueling?
Thanks in advance.
Orbiter
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#192
by
2552
on 18 Apr, 2010 01:23
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He then said "And I expect to be around to see it." That implies by 2050 or so.
No, he said: "By the mid-2030s, I believe we can send humans to orbit Mars and return them safely to Earth. And a landing on Mars will follow. And I expect to be around to see it."
That implies late 2030s/early 2040s. Obama is 48 now, he would be 78 during a Mars landing in 2040.
Well, I was wondering what Asteroid could we possibly go to? I was thinking, because Apophis is going to come near Earth in 2029 we could visit that in 2025-26, to possibly learn ways to deflect Asteroids coming towards Earth.
An Apophis mission seems more likely to happen in 2029, during or soon after the close approach, so it could be reached faster.
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#193
by
anonymous
on 18 Apr, 2010 16:05
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2025 is the only launch window for a mission to 1999AO10. That's probably the target Obama's advisers had in mind. I think Apophis would require a lot more delta-v. I don't know that there would be a suitable launch window. At the close approach in 2029 Apophis will swing past Earth at a relative velocity of 7 km/s - that's the total delta-v required for the mission to 1999AO10.
Landing on Mars is much more expensive than orbiting it or visiting Phobos. It requires much more capability and much more mass. I thought Obama phrased the statement about landing quite cleverly.
I also think that Obama's "we've been there" remark about the Moon, while focusing on Mars instead was right politically, even though that isn't the real reason.
Nobody outside the sort of space enthusiasts here is interested in the Moon these days. It's not just that we've been there, it's that when we did go there people didn't find it interesting. It's a colourless dead rock. The dust covers everything so that the hoped-for spectacular lunar mountains Apollos 15 and 17 visited looked like rolling hills.
Mars, on the other hand, has a certain allure because it's mysterious and its colours are rather attractive to human eyes. Searching for evidence of life in the lost rivers and lakebeds is a romantic endeavour. That's more what space travel is supposed to be like.
By saying "we've been there", he also undercut Bush's "Vision" as old hat and forestalled any future Chinese ambitions on the Moon (if they have them) as so last century.
The problem with visiting NEOs is that most people don't find them interesting at all. But they're a lot cheaper uninteresting destinations than the Moon. They are stepping stones to Phobos and then to Mars, while the Moon is a diversion.
Do I think what Obama set out will happen? No. The Republicans will cancel the plan when they regain the White House. He was presented by the Republicans with a spaceflight gap and an unworkable plan, so now they're blaming him for the consequences. Obama is damned if he does and damned if he doesn't. If he focuses on dealing with the gap, people here say that he doesn't have a long-term vision. If he talks about a long-term vision, people say it'll never happen and so he's not serious. He proposes to buy space services from competing companies like ULA and SpaceX. Republicans denounce him as unpatriotic for wanting to rely on private companies, not continue a government-owned system with massive fixed costs that coincidentally delivers lots of pork to Texas, Alabama and Utah. As Mike Gold of Bigelow Aerospace said, "if you could fuel a rocket on hypocrisy we'd be on Pluto by now."
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#194
by
Arthur
on 18 Apr, 2010 17:06
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As Mike Gold of Bigelow Aerospace said, "if you could fuel a rocket on hypocrisy we'd be on Pluto by now."
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#195
by
simonth
on 18 Apr, 2010 17:57
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I wonder whether the approach to go to a NEO first and then many years later to Phobos or Deimos is the right thing to do. Personally, I think considering the limited funds NASA does have and the preparation required, Mars orbit should be the primary and most important goal and be focused on for mid-2020s. A NEO mission can be done as a separate mission if funds are available, but shouldn't be done as a priority.
I believe a mid-2020s date for a 4-crew Mars orbital mission would be the goal that NASA needs and which would help it to focus and invest in the right technology.
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#196
by
SpacexULA
on 18 Apr, 2010 18:42
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I wonder whether the approach to go to a NEO first and then many years later to Phobos or Deimos is the right thing to do. Personally, I think considering the limited funds NASA does have and the preparation required, Mars orbit should be the primary and most important goal and be focused on for mid-2020s. A NEO mission can be done as a separate mission if funds are available, but shouldn't be done as a priority.
I believe a mid-2020s date for a 4-crew Mars orbital mission would be the goal that NASA needs and which would help it to focus and invest in the right technology.
Part of the issue is everything besides geology and human sciences can be done better by unmanned craft. A fly by of Mars doesn't contribute to human knowledge much relative to it's costs.
A NEO object is the lowest delta V target where we can let a human hit a rock with a pick.
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#197
by
simonth
on 18 Apr, 2010 18:45
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A NEO object is the lowest delta V target where we can let a human hit a rock with a pick.
Most NEOs that can be visited in a 180 day mission are higher delta V targets than Deimos and Phobos. The Martian moons are among the low delta-v targets, they however require longer mission timelines.
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#198
by
SpacexULA
on 18 Apr, 2010 19:03
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A NEO object is the lowest delta V target where we can let a human hit a rock with a pick.
Most NEOs that can be visited in a 180 day mission are higher delta V targets than Deimos and Phobos. The Martian moons are among the low delta-v targets, they however require longer mission timelines.
Exactly. A few can be visited at a lower Delta V, and at and lower mission duration.
That is the point of flexible path, to give the American people milestones every few years, instead of thinking American's have the capacity to increase an agencies funding each year for a decade without milestones being spoon fed to them, because we don't.
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#199
by
sdsds
on 19 Apr, 2010 00:57
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2025 is the only launch window for a mission to 1999AO10.
Yes, the limited launch windows look like a somewhat unique characteristic of these NEO targets for HSF. The article quotes the presentation as saying:
“A robust example program can be constructed in which a human mission scheduled for launch in 2025 could withstand a one-year launch slip, while being preceded by a robotic reconnaissance precursor mission launched in 2019 that itself could withstand a one- or two-year launch slip.”
If the mission to 1999AO10 were to slip its schedule past the "second chance" launch opportunity, it would then have to retarget to a different NEO completely.... Apollo to the Moon wasn't like that!
