[FPSPACE] Dual Orion capsules studied for manned asteroid missions

[Michael K. Heney]

Hmmm - interesting. The mass of Apophis (per Wikipeda) is 21,000 tonnes - 
or about 150 times the mass of that supertanker.  Sounds like imparting 
non-trivial delta-V is not an unreasonable proposition - assuming the rock 
is not a rubble pile ...


On Mon, 24 Aug 2009, Jens Kieffer-Olsen wrote:

> Although Apophis is very much more massive than Messenger
> its orbit needs less change to enter Earth orbit than does that
> spacecraft to enter orbit around Mercury.
>
> In both cases the bulk of the change will stem from slingshot
> effects, whereas nudging is merely the mechanism to fine-tune
> the slingshots.
>
> The size of planets makes the difference in size between Messenger
> and Apophis unimportant. Just as Larry Ellison's yacht Rising Sun
> and the world's largest container ship Emma Maersk ( with a
> deadweight of 156,000 tonnes ) obey the same principles of
> hydromechanics.
>
> The 2029 pass of Apophis within GEO distance provides a strong,
> natural slingshot effect. Just as there exists a so-called 'keyhole'
> passing through which in 2029 Apophis will be able to target Earth
> for a direct hit in 2036, other keyholes exist that will permit Apophis
> to repeat its close encounters with Earth in later years, and thus
> allow us to plan a chain of slingshots, just like Messenger goes
> through a series of such.
>
> Attaching ion engines to Apophis well before 2029 will enable the
> desired fine-tuning of the pass, directing the asteroid through a
> pre-calculated keyhole. The exercise is similar to the deflection
> required, if we wanted instead to prevent Apophis from passing
> through the keyhole causing a 2026 collision.
>
> --
> Jens Kieffer-Olsen
> Slagelse, Denmark
>
>
> -----Original Message-----
> From: Michael K. Heney [mailto:mike at heney.net]
> Sent: Sunday, August 23, 2009 4:44 PM
>
> Take a look at J002E3 - initially thought to be a NEO when discovered in
> September 2002, it turned out to be the S-IVB from Apollo 12.  The stage
> entered a heliocentric orbit after sending Apollo 12 on its way to the
> moon; in 2002, it was recaptured into a chaotic orbit as it passed near
> the Earth-Sun L1 point; it was ejected back into heliocentric orbit in
> July 2003, and may do it again sometime in the 2030-2040 timeframe...
>
> So, nudging Apophis (an exercise left to the reader...) to interact with
> the L1 (or L2 point) for capture into an unstable orbit, and then tweaking
> that orbit to something more stable would do the trick.
>
> Of course, there IS a wee difference in situations (ignoring mass) ...
> The S-IVB is in an earth-grazing orbit - with an eccentricity only
> slightly different than Earth's.  It approaches gently, on a tangent to
> the L-1 point.  Apophis is an Earth-crossing asteroid, with an
> eccentricity of about .19 - it's movin' on through as it approaches Earth.
> You'd want to bump it's aphelion down from 1.1 AU to closer to 1, raise
> the perihelion from .75 to something much closer to 1, and do it in such a
> way so that it still ends up near the Earth so it can be captured.
>
> That's a lot of noodging on a good-sized (350m) rock ...
>
>
> On Fri, 21 Aug 2009, David R. Woods wrote:
>
>> Jens,
>>
>> Do you know of any references that describe how that capture process could
> take place?
>> Typically, with conservation of momentum, there is too much energy for
> something to be captured
>> if it comes in from beyond Earth's gravitational well.  I could see a
> sling shot maneuver using
>> the Moon to somehow put it into a retrograde orbit, but that seems bazaar
> and dangerous if you
>> did not get it exactly right.
>>
>> Dave
>>
>> -------- Original Message --------
>> Subject:
>> Re: [FPSPACE] Dual Orion capsules studied for manned asteroid missions
>> Date:
>> Fri, 21 Aug 2009 21:58:17 +0200
>> From:
>> Jens Kieffer-Olsen <dstdba at post4.tele.dk>
>> Reply-To:
>> dstdba at post4.tele.dk
>> Organization:
>> Indian Red
>> To:
>> <fpspace at friends-partners.org>
>>
>> <snip>
>>
>> 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.
>>
>> <snip>
>> Jens Kieffer-Olsen
>> Slagelse, Denmark
>>
>>
>
>
>
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