[SpaceProgram] Lagrange Solar Sail Challenge

[Matt Johnson]

Interesting. Longer than I thought.

--
Matt Johnson

On Thu, Oct 4, 2012 at 1:54 PM, Lee von Kraus <leevonk at gmail.com> wrote:
> not considering wind resistance it would take:
>
> 11.1 seconds to fall 2000 feet, or
>
> 13.7 seconds to fall 3000 feet.
>
> (I used this website: http://www.gravitycalc.com/)
>
>
>
>
>
> On Thu, Oct 4, 2012 at 12:44 PM, Matt Johnson <railmeat at gmail.com> wrote:
>>
>> How long would the free fall be for a 2000 foot fall? I wonder if it
>> would be enough. We would probably need a much higher balloon and
>> tether. Of course this exacerbates the problems of hoisting the tether
>> and gondola and powering the gondola. This is almost starting to sound
>> like engineering.
>>
>> --
>> Matt
>>
>> On Thu, Oct 4, 2012 at 7:53 AM, Lee von Kraus <leevonk at gmail.com> wrote:
>> > the website says the helikites can go up "thousands" of feet, not sure
>> > how
>> > many thousands though, but I guess at least more than 2000 if their
>> > using
>> > the word correctly.
>> >
>> > You're right about all that cable weight weighing things down too much.
>> > So
>> > it might be best to have a space-elevator-like gondola (as suggested
>> > previously by Matt) thing that can climb up the single rope that's
>> > anchoring
>> > the helikite to the ground. The gondola can be powered by a laser from
>> > the
>> > ground (although I'm not sure how far a reasonably sized laser can shoot
>> > power). That gondola would drive the capsule up to the helikite and then
>> > 'throw' the capsule off and let it fall to the ground where we could
>> > have
>> > some sort of cushion to catch it. The capsules could have fins on them
>> > to
>> > better ensure that they fall straight down
>> >
>> > As the fallen capsule is being retrieved the gondola would already be on
>> > its
>> > way back down to get the same, or another capsule. The system wouldn't
>> > be
>> > too speedy but would still be a useful tool, I'd imagine the demand for
>> > usage would be pretty high from schools and amateur scientists that
>> > can't
>> > afford other micro-G options.
>> >
>> >
>> >
>> >
>> > On Thu, Oct 4, 2012 at 7:29 AM, Jerry Isdale <jerry at mauimakers.com>
>> > wrote:
>> >>
>> >> Depending on how high you go and the kg/m mass of the cable, it is
>> >> possible that the weight of the 2x length of cable could be more than
>> >> the
>> >> weight of the winch.
>> >> using this kevlar rope as a guide...
>> >> http://www.pelicanrope.com/kevlar12strandrope.html
>> >> say we pick the 7/16", 15,000lb tensile strength rope at 5lbs/100ft.
>> >> ('cause thats an easy weight)
>> >> a 1,000ft length will weigh... 50lbs?
>> >>
>> >> 1000 ft will not give much free fall time. Parabolic flights are on the
>> >> order of 8000ft deltas ...400lbs
>> >> Although rolling all that cable up into the helikite would require a
>> >> lot
>> >> of space/big spool.
>> >>
>> >> Jerry Isdale
>> >> http://MauiMakers.com
>> >> http://www.mauimakers.com/blog/thursday-public-meeting/
>> >>
>> >> On Oct 3, 2012, at 5:04 AM, Lee von Kraus wrote:
>> >>
>> >> The best way to maximize the allowable experimental capsule weight
>> >> would
>> >> be to have all the motor mechanisms on the ground as shown in the
>> >> attached
>> >> figure. That way the only mechanism, other than the capsule, that needs
>> >> to
>> >> be carried by the helikite is a pulley (and the weight of the capsule
>> >> line).
>> >>
>> >>
>> >>
>> >> On Wed, Oct 3, 2012 at 10:42 AM, Lee von Kraus <leevonk at gmail.com>
>> >> wrote:
>> >>>
>> >>> Here are some useful excerpts:
>> >>> "
>> >>> The 10 cubic metre Skyhook Helikite is able to fly to thousands of
>> >>> feet
>> >>> in winds up to 50 mph lifting a payload of 5kg.
>> >>>
>> >>> Helikites are designed for foul weather deployment and foul weather
>> >>> flight. Even the largest Skyhook Helikites can be launched and
>> >>> retrieved in
>> >>> all the winds that they can fly in. So deployment and flight can occur
>> >>> safely in winds up to 50 or 60 mph.
>> >>>
>> >>> The new Cased Helikite Aerostat Maintainable Platform (CHAMP) (see
>> >>> products section) allows the deployment of a 10 cubic metre Skyhook
>> >>> Helikite
>> >>> within 30 minutes. The unique part of the CHAMP is that it also
>> >>> includes an
>> >>> excellent Helibase with top cover thus also creating a permanent, safe
>> >>> base
>> >>> for the Helikite - not just a minimal launch platform.
>> >>>
>> >>> Helikites can even be launched and recovered remotely - with no people
>> >>> present at all. They are simply winched off or onto the Helibase.
>> >>> "
>> >>>
>> >>>
>> >>> On Wed, Oct 3, 2012 at 10:37 AM, Lee von Kraus <leevonk at gmail.com>
>> >>> wrote:
>> >>>>
>> >>>> here is a link better describing the advantages of helikites:
>> >>>>
>> >>>> http://www.allsopp.co.uk/index.php?mod=page&id_pag=24
>> >>>>
>> >>>>
>> >>>>
>> >>
>> >>
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