[FPSPACE] Dual Orion capsules studied for manned asteroid missions

Fri Aug 21 20:58:46 EDT 2009

Jens:

We won't go after a space elevator anchor point until we need a space elevator. We won't grab an asteroid and park it on the off-chance that we'll decide someday to build one. Will we need a space elevator any time soon? I'm sorry, I just don't see it, as cool as it would be.

Before we can think about using any asteroid as such an anchor point - which might not be necessary anyway - we need to learn more about it. What if Apophis is a rubble pile that squirms around as we try to push it? 

I've heard how VASIMR is right around the corner and is going to be test flown in space for a decade or two now, so pardon me if I'm a little skeptical. In any case, if you're going to use rockets, why not electric thrusters? We know they work. 

And, don't you think it would be a bit tricky politically to nudge an asteroid into GEO? I mean, given all the hype that has been tossed around about the threat from asteroids, who is going to support actually pushing one toward the Earth? 

I don't mean to be a party pooper, and I don't doubt that some version of your scenario will be plausible at some point. Twenty years or so ago I wrote in an article that "soon" no asteroid would dare come near to Earth because the cislunar industrial infrastructure would snap it up. Maybe your scenario will play out someday. But not by 2029. That is, after all, only 20 years in the future. 

In the meantime, we have a lot of other spadework to do.

David S. F. Portree

dsfportree at hotmail.com
dportree at usgs.gov

http://robotexplorers.blogspot.com/
http://beyondapollo.blogspot.com/

http://astrogeology.usgs.gov/About/People/DavidPortree/

From: dstdba at post4.tele.dk
To: fpspace at friends-partners.org
Date: Fri, 21 Aug 2009 21:58:17 +0200
Subject: Re: [FPSPACE] Dual Orion capsules studied for manned asteroid missions

Well, well, well, David.

I'll try to be a bit more detailed with respect to the ACSEP ( Apophis Capture and
Space Elevator Project ).

As you know Rusty Schewickart has asked that a transponder mission be launched
by NASA in order to ascertain the asteroid's precise characteristics. Although his
concern is solely to obviate a hypothetical collision with Earth, the same transponder
mission is also the first part of ACSEP. Only by knowing the precise orbit of Apophis
can the necessary combination of nudges and slingshots be calculated that will eventually
deliver the asteroid into GEO.

A manned mission to Apophis to install a VASIMR ion engine is the second part of
ACSEP. As you must be aware NASA's Charles Bolden is very excited about Franklin
Chang-Diaz' and his Ad Astra company's new engine, having agreed to test it for ISS
use around 2013. So, there is plenty of time to attach one or more  VASIMR engines
to Apophis prior to 2029.

The eventual capture of Apophis into GEO could presumably take place later this
century, taking us into the third part of ACSEP.

And yes, the details of the space elevator itself may be a bit tenous right now. However,
there is no expiry date attached to Apophis once it's in GEO. When the elevator concept
is doable, Apophis is ready as anchor point. 

The 2029 close pass of Apophis offers a once-in-a-century chance of capturing a valuable
asteroid into GEO. There is no good reason at all for NASA to pussy-foot or dismiss
ACSEP as science fiction. 

--
Jens Kieffer-Olsen
Slagelse, Denmark

-----Original Message-----
From: David Portree [mailto:dsfportree at hotmail.com] 
Sent: Thursday, August 20, 2009 10:09 AM
To: dstdba at post4.tele.dk; fpspace at friends-partners.org
Subject: Re: [FPSPACE] Dual Orion capsules studied for manned asteroid missions

Jens:

Leaving aside your proposed plot for a science fiction movie (which has no where near enough sex in it to sell, by the way) - the piloted L point mission concept gained prominence first during the Decadal Planning Team exercise begun in 1999. They were desperately straining to come up with reasons to launch humans beyond LEO, but without breaking the bank (that is, without a moon landing). With the HST servicing missions in mind, they came up with deployment and servicing of large L point telescopes as a possible justification. It's not an entirely silly notion, though after all the scaredy-cat hemming and hawing and "rescue" preparations for the last HST servicing mission, it's hard to see how an even riskier mission to service a telescope at an L point could be justified.

David S. F. Portree

dsfportree at hotmail.com
dportree at usgs.gov

http://robotexplorers.blogspot.com/
http://beyondapollo.blogspot.com/

http://astrogeology.usgs.gov/About/People/DavidPortree/

> From: dstdba at post4.tele.dk
> To: fpspace at friends-partners.org
> Date: Thu, 20 Aug 2009 02:57:23 +0200
> Subject: Re: [FPSPACE] Dual Orion capsules studied for manned asteroid missions
> 
> 
> -----Original Message-----
> From: David Portree [mailto:dsfportree at hotmail.com] 
> Sent: Wednesday, August 19, 2009 3:31 PM
> 
> > Just because an asteroid passes one million kilometers from
> > Earth doesn't mean one could reach it as easily or as quickly
> > as an L point. Furthermore, not all asteroids are worth
> > reaching, and this mission would focus on which are accessible
> > by straining the Orion system, not on the value of the targets;
> > basically, it'd be a stunt. Finally, for the cost of this stunt
> > mission, we could send robot explorers to a dozen more interesting
> > asteroids.
> 
> Yes indeed, a mission without a concrete purpose is a stunt!
> 
> Travelling to the Sun-Earth L2 point 1.5 million km away will not
> be justified until a permanent base is planned. The only resource
> there is sunlight. Hell, to paraphrase Robert Zubrin, it's a case
> of 'living off the void'.
> 
> It would make more sense to first practice one's station-keeping
> skills at the Earth-Moon L2 point just 440,000 km away from home.
> In fact, EML2 was recently proposed a potential staging node
> for 'Back-to-the-Moon' missions.
> 
> As for asteroids I could envisage a bold mission in 2029 to try
> to capture Apophis! That year it's passing Earth closer than the
> orbits of geostationary satellites, so if it were nudged slightly
> beforehand, the slingshot effect of the pass could be tailored
> to bring Apophis into Earth orbit as a captured moon on a future
> encounter.
> 
> Having not run this through a computer program, it's quite possible
> that we would have to nudge the orbit of Apophis on several passes
> in order to effectuate a capture, but the point remains that the
> first nudge is asking to be carried out before 2029.
> 
> Allow me to suggest that NASA right away spend a fair sum of
> taxpayers' dollars on a feasibility study! And maybe some
> environmental group could be persuaded to launch a 'No Asteroid
> in my Backyard' campaign to attract publicity to the scheme!
> 
> If Apophis could become the anchor point for the world's first
> space elevator, it's time to act NOW! 
> 
> --
> Jens Kieffer-Olsen
> Slagelse, Denmark
> 
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