Obama's asteroid goal: tougher, riskier than moon

[orionrider]

Europe as a political entity lacks the kind of national pride and leadership necessary to go anywhere far. Maybe the people would like to, but not the politicians. That is where NASA could play the role of a catalyst. If Obama publicly asked Germany to cooperate in a joint mission, the Germans would happily give him their euros. No politician would dare to refuse. Remember, the guy has 90% popularity over there
After that France, Italy, Belgium, Spain and the others would follow suit.
If the mission were to fail, it would be the great Satan's fault. And if it succeeds, everyone will say they were part of it. :mrgreen:

 

[HopDavid]

What are dV differences from EML1 to those asteroids ?

It takes about .6 km/sec to drop from EML1 to an elliptical orbit with a 300 km perigee.

At this perigee, a ship's travelng almost escape, about 3 km/sec faster than a circular LEO orbit.

So, in general, the EML1 advantage over LEO is about 2.4 km/sec.

 

[EarthlingX]

From Wiki, Moon

There are several known near-Earth asteroids that have unusual Earth-associated horseshoe orbits: 3753 Cruithne, 54509 YORP, (85770) 1998 UP1 and 2002 AA29.[79]

[79] - The Population of Near-Earth Asteroids in Coorbital Motion with the Earth


Wiki : 3753 Cruithne

3753 Cruithne (pronounced /ˈkrɪnjə/, from Old Irish [ˈkrɪθnɛ]; Modern [ˈkrɪhnʲə] or [ˈkrɪnʲə]) is an asteroid in orbit around the Sun in 1:1 orbital resonance with that of the Earth. It is a periodic inclusion planetoid orbiting the Sun in an apparent horseshoe orbit.[2] It has been called "Earth's second moon", although it is only a quasi-satellite.[2]

This one has also very interesting orbit.

Minor planet category : Near-Earth asteroid, Venus-crosser asteroid, Mars-crosser asteroid

How far is that, in dV from EML1 ? It should be less than Moon, i guess ?

 

[orionrider]

Very, very interesting. Thank you EarthlingX!

 

[HopDavid]

From Wiki, Moon

There are several known near-Earth asteroids that have unusual Earth-associated horseshoe orbits: 3753 Cruithne, 54509 YORP, (85770) 1998 UP1 and 2002 AA29.[79]

[79] - The Population of Near-Earth Asteroids in Coorbital Motion with the Earth


Wiki : 3753 Cruithne

3753 Cruithne (pronounced /ˈkrɪnjə/, from Old Irish [ˈkrɪθnɛ]; Modern [ˈkrɪhnʲə] or [ˈkrɪnʲə]) is an asteroid in orbit around the Sun in 1:1 orbital resonance with that of the Earth. It is a periodic inclusion planetoid orbiting the Sun in an apparent horseshoe orbit.[2] It has been called "Earth's second moon", although it is only a quasi-satellite.[2]

This one has also very interesting orbit.

How far is that, in dV from EML1 ? It should be less than Moon, i guess ?

Most of my delta V approximations rely on patched conics using two body models.

My models using EML1 deviate a little from this. Without the moon a 320,000 altitude circular orbit would move at 1.1 km/sec. But with the moon, EML1 is a circular orbit with a velocity of .87 km/sec. So I reduce my burn for dropping out of EML1 by (1.1-.87) or about .2 km/sec. A quick and dirty trick, but one that seems to work OK when I plug it into 3 body orbit sims. Using a .6 km/sec burn rather than an .8 km/sec burn works well to drop a ship into an elliptical orbit with a 300 km perigee.

But the chaotic orbit of Cruithne is too deep into Belbruno Land for me to take a stab at. Sorry.

 

[EarthlingX]

Thanks for the effort

I checked around on jpl a bit and found this table of close approaches, and it doesn't look so good, i think we found better candidates before :

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=3753 Cruithne;orb=1;cov=0;log=0;cad=1#cad

V-relative is big - 15 - 16 km/s, probably because it has a nasty inclination - 19.81°

Orionrider thank you, you brought a lot of ratio in this discussion

 

[HopDavid]

Thanks for the effort

I checked around on jpl a bit and found this table of close approaches, and it doesn't look so good, i think we found better candidates before :

http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=3753 Cruithne;orb=1;cov=0;log=0;cad=1#cad

V-relative is big - 15 - 16 km/s, probably because it has a nasty inclination - 19.81°

Orionrider thank you, you brought a lot of ratio in this discussion

If we're talking about a manned mission, launch opportunities are few and far between. I believe Orionrider and Meteor Wayne have already pointed this out.

But with robotic missions, 7 month trip times aren't a show stopper. If time isn't a factor, the number of launch windows for doable delta V missions increases dramaticly.

For most asteroids, mining their resources is beyond autonomous robots. Beyond telerobots also, since the light lag is too high.

But given an extinct comet with internal volatile ices, I believe a Kuck Mosquito might work.

Are there such extinct comets with accessible delta V? Popular wisdom is that any such bodies would have 30 A.U. aphelions and thus would be traveling too fast when in our neighborhood. I put together a page of links suggesting there may be accessible asteroids with volatiles: Asteroid Resources.

I am happy to see you singing the praises of WISE. I believe this scope will provide valuable information on exploitable asteroids.

 

[orionrider]

There is another way, cheaper but riskier.
In fact, the only think that has to fly fast is the delicate human cargo. All the rest can be launched separately.

1. The propellant, life support and equipment needed for exploration and a return voyage are sent using the most efficient scheme: gravity assist, ion/plasma thrusters,... It doesn't matter if it takes years to get there.

2. A very small and light manned craft leaves the ISS with a large acceleration burn. After a short transit, it 'brakes' to adjust velocity with a second large burn. The trip is very fast, very short, less than one week.

3. On arrival, the (3?) astronauts transfer to the living module containing all the resources needed for 2 weeks of exploration: air, food, water, spacesuits, tools, etc.

4. Then the capsule is mated to the return module waiting at the asteroid and repeat the 2-burn scheme to come back to the ISS.

Ultimately the only thing to come back is the light craft with the astronauts and samples. All the rest would be abandoned near the asteroid or in deep space. The crew would return to Earth with a regular Dragon/Soyuz capsule. The travel craft doesn't need to be very strong because it is not designed for gravity or reentry. A small Bigelow-like module would be sufficient.

What do you think?

 

[HopDavid]

There is another way, cheaper but riskier.
In fact, the only think that has to fly fast is the delicate human cargo. All the rest can be launched separately.

1. The propellant, life support and equipment needed for exploration and a return voyage are sent using the most efficient scheme: gravity assist, ion/plasma thrusters,... It doesn't matter if it takes years to get there.

2. A very small and light manned craft leaves the ISS with a large acceleration burn. After a short transit, it 'brakes' to adjust velocity with a second large burn. The trip is very fast, very short, less than one week.

3. On arrival, the (3?) astronauts transfer to the living module containing all the resources needed for 2 weeks of exploration: air, food, water, spacesuits, tools, etc.

4. Then the capsule is mated to the return module waiting at the asteroid and repeat the 2-burn scheme to come back to the ISS.

Ultimately the only thing to come back is the light craft with the astronauts and samples. All the rest would be abandoned near the asteroid or in deep space. The crew would return to Earth with a regular Dragon/Soyuz capsule. The travel craft doesn't need to be very strong because it is not designed for gravity or reentry. A small Bigelow-like module would be sufficient.

What do you think?

I certainly agree that any manned mission should be preceded by unmanned deliveries to the asteroid.

I am worried about the 1 week manned trip though. In trying to find quick paths to asteroids during close approaches, I'd usually get a path that crossed both the earth and asteroid orbit at a good angle.

Notice with the Hohmann trip, the arrival and destination vectors are parallel, no direction change needed. But the sprint orbit crosses both earth's and the asteroid's orbit at a good angle. It requires a lot of delta V for direction change.

The above doesn't show all the possible geometries. But I would have to see the planned mission in more detail. In general I'd say a one week trip to any asteroid, even passing by at 3.1 LDs, would be difficult. Even if the passenger craft were fairly light, the steep delta V requirements are a formidable obstacle. There may be exceptions, though.

 

[EarthlingX]

So plan would be to set EML1 as a next staging point after LEO, and then start adventuring with longer excursions, where-ever that may be, as long as no extra engines/lander is needed. Everything can stay in space, except crew transfer craft, which would hopefully be reusable, and could be used as a command module for assembled ship.

It seams that what is needed is capability to stay independent of resupply for longer periods of time. I guess that for low Isp/high thrust engines it might be more mass efficient to have more supplies, meaning longer travel, and for high Isp engines it might be more efficient to have more fuel, which could translate to a shorter travel on longer distances.
This assumption doesn't take into account fuel evaporation losses, which will depend on the choice of propellant and technology advances.

I wonder where are the break points, what is the most optimal distance, in dV, time, from EML1 ? This will change, as new technology becomes available, of course, but there must be a sweet spot ?

 

[EarthlingX]

An older, but related article about cooperation and NASA :

www.spacenews.com : New NASA Direction Spurs Hopes for Cooperation

Fri, 11 June, 2010

By Peter B. de Selding

BERLIN — NASA Deputy Administrator Lori Garver told a largely European audience here June 10 that the U.S. space agency’s proposed new direction leaves substantially more room for international partnerships than the Moon-focused Constellation program that it would replace.

Attending the Berlin air show, ILA 2010, Garver said Constellation, which the administration of U.S. President Barack Obama is asking Congress to cancel, ultimately would have consumed 50 percent of NASA’s budget and “was closed off to international cooperation.”

 

[orionrider]

http://impact.arc.nasa.gov/news_detail.cfm?ID=184
POTENTIAL CANDIDATE NEAS FOR HUMAN VISITS
From Rob Landis, NASA ARC / JSC:
Here are the so-called 'Big 6' NEAs that have been identified as potential targets for human visits, together with nominal diameters. None of these has been characterized beyond determining its brightness and orbit.

- 1998 HG49 [143 m]
- 2001 BB16 [104 m]
- 2003 SM84 [100 m]
- 2000 AE205 [ 90 m]
- 2001 QJ142 [ 72 m]
- 2009 OS5 [ 70 m]
- 1999 AO10 [ 60 m]

The last one seems to be the prime candidate. I have found very little on Google about this rock, apart from a close approach at 0.027AU (November 2026).
Can someone with better understanding of the math involved (HopDavid?) tell me what dV it will have? Nasa speaks of a 150 day mission, with 2 weeks on site.

This particular asteroid is described in the latest issue of the French magazine 'Science & Vie' as the target of a mission starting in 2025. If the manned flight lasts 150days, it means the ship taking off in 2025 would be the 'slow' supply ship sent in advance :?:

 

[EarthlingX]

From
http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=1999 AO10;orb=1;cov=0;log=0;cad=1#cad

close approach on : 2012-Aug-10 13:07, time uncertainty : 2 days 20:25 min
Nominal Distance (AU) : 0.203010103854925
V-relative (km/s) : 5.67462133179167

absolute magnitude H 23.855 mag

This one ?

 

[orionrider]

Thanks, great link as well

In fact, landing is planned for Feb 2026. I read a dV of 2.7km/sec which is excellent.

See also: http://unicorn.eis.uva.es/neodys/index. ... n=1999AO10

I wonder what trajectory the supply ship could follow and how long it would have to travel? We're speaking masses in excess of 50 tons here. Unless VASIMR gets improved real fast, it will have to be chemical :?

 

[vulture4]

I have difficulty understanding the objective of a human mission to an asteroid. A landing (NEAR) and a landing and return (Hyabusa) have already been accomplished. What scientific objective is there that can't be accomplished much less expensively with robotic systems?

 

[scottb50]

I have difficulty understanding the objective of a human mission to an asteroid. A landing (NEAR) and a landing and return (Hyabusa) have already been accomplished. What scientific objective is there that can't be accomplished much less expensively with robotic systems?

At this point in time I would have to agree. Maybe the 1.5 version, most everything seemed to work until landing with Hyabusa. A Falcon 1 could probably launch a compact version with a solid stage.

 

[rockett]

I have difficulty understanding the objective of a human mission to an asteroid. A landing (NEAR) and a landing and return (Hyabusa) have already been accomplished. What scientific objective is there that can't be accomplished much less expensively with robotic systems?

I agree wholeheartedly. At the present time, it seems mostly a very risky boots and flags effort to me. Or perhaps a goal never intended to be reached for political reasons.

As for the ones who argue "Prevent armageddon!" and "Study the harbingers of doom!" that is not a sound reason. They seem to forget that there are thousands of asteroids, and from what we know so far, they vary radically in composition and cohesiveness. No telling what type might put us in the crosshairs, so a strategy for one might be useless for another as far as preparing for a collision.

 

[EarthlingX]

To get to the asteroid you will need a lot of not yet existing capabilities. Using asteroid resources will most likely have to be done on-site, at least until we are capable of asteroid relocation.
A single asteroid in the Moon orbit could provide resources to in-space industry for a very long time.

It is a low hanging fruit, and as a result we get a real spaceship, with technology to build more, which can get us to the next step, where-ever that may be.

Asteroids are the most common type of space rocks in the Solar system, and we know very little about them, except for a few.

 

[orionrider]

The asteroid is not a goal, it's a destination for a shakedown mission. This target is meant to develop the knowledge, equipment and skills needed to exit Earth orbit (which has never been done).

And there is something else: an asteroid is like a train, it leaves on time!
When President Obama spoke of 1999AO10, he committed the mission for Feb. 2026. Another target (L1 or Moon) could have been postponed indefinitely, with costs rising until the whole show got canceled, like so many costly dreams...

 

[kelvinzero]

You are implying that congress is governed by the laws of physics?

 

[orionrider]

At least once they sign the bill, they can't make the rock slow down. Also, the contractors can't digress. They have to be ready by the deadline

 

[rockett]

At least once they sign the bill, they can't make the rock slow down. Also, the contractors can't digress. They have to be ready by the deadline

Not necessarily. We all know how "on time" and "on budget" Constellation was. Historically that has always been the case when Congress wants to rob the NASA "piggy bank".

 

[orionrider]

Ah, but Constellation was doomed from the beginning because there was no way to do it with the nominal budget. And it could be delayed with no big consequences.

With 1999AO10 it is Feb. 2026, not a minute later.

The second big difference is that the asteroid mission will be international and commercial. NASA will need the ISS, the Soyuz, SpaceX, Bigelow, ESA's biomedical expertise and JAXA's experience with NEA. Once half of the world is committed, Congress has to follow unless they want to look like fools - again. And believe me, this time Russia and Europe are going to place safeguards and lawyers at every corner of the contract. Not to mention Elon Musk
When you work with partners, you can't change your mind every 4 years.

Obama is one smart SOB. He's got Congress cornered on this one, they don't even know it :lol:

 

[MeteorWayne]

I tried search for Atens and these three came on top :

Object | Close-Approach Date | Miss Distance Nominal (LD/AU) | Miss Distance Minimum | V relative | V infinity | N sigma | H (mag)
-------------------------------------------------------------------------------------------------------------------------------------------
(2007 DD) _ 2010-Jun-17 21:09 ± 00:01 _ 33.3/0.0856 _ 33.3/0.0856 _ 2.25 _ 2.24 _ 2.03e+04 _ 25.8

(2010 LG61) _ 2010-Jun-21 18:49 ± 3 03:11 _ 25.6/0.0659 _ 0e+00/0.0e+00 _ 3.24 _ 3.23 _ 0.552 _ 24.0

(2007 CS5) _ 2010-Jun-24 02:17 ± 1 08:51 _ 22.5/0.0578 _ 14.6/0.0375 _ 3.42 _ 3.41 _ 1.58e+03 _ 24.5
-------------------------------------------------------------------------------------------------------------------------------------------

Link above should be directly to the results page.

They are not exactly around the corner, but how they compare to Phobos ? Answer is probably in inclination .. ?

I don't think we're ready to launch this week

 

[Valcan]

I tried search for Atens and these three came on top :

Object | Close-Approach Date | Miss Distance Nominal (LD/AU) | Miss Distance Minimum | V relative | V infinity | N sigma | H (mag)
-------------------------------------------------------------------------------------------------------------------------------------------
(2007 DD) _ 2010-Jun-17 21:09 ± 00:01 _ 33.3/0.0856 _ 33.3/0.0856 _ 2.25 _ 2.24 _ 2.03e+04 _ 25.8

(2010 LG61) _ 2010-Jun-21 18:49 ± 3 03:11 _ 25.6/0.0659 _ 0e+00/0.0e+00 _ 3.24 _ 3.23 _ 0.552 _ 24.0

(2007 CS5) _ 2010-Jun-24 02:17 ± 1 08:51 _ 22.5/0.0578 _ 14.6/0.0375 _ 3.42 _ 3.41 _ 1.58e+03 _ 24.5
-------------------------------------------------------------------------------------------------------------------------------------------

Link above should be directly to the results page.

They are not exactly around the corner, but how they compare to Phobos ? Answer is probably in inclination .. ?

I don't think we're ready to launch this week

Nonsense we can use the secret government UFO's at area 51 and land on the moon base we stole from the Nazies. See easy.
Sniff