[AR] Re: Air Launch Reference
- From: Bill Claybaugh <wclaybaugh2@xxxxxxxxxx>
- To: "arocket@xxxxxxxxxxxxx" <arocket@xxxxxxxxxxxxx>
- Date: Mon, 16 Feb 2015 19:02:24 -0500
Sorry, how would that work?
Isn't Strato--as an example--using a custom made dedicated launch vehicle? How
would my costs be lower of I develop another rocket to use that platform? And
why would they fly a competitor?
Bill
Sent from my iPhone
On Feb 16, 2015, at 3:13 PM, Henry Vanderbilt <hvanderbilt@xxxxxxxxxxxxxx>
wrote:
> Another additional observation: Once something like Proteus, or WK1/2, or
> Stratolauncher has been built and is being operated regardless, the potential
> for buying additional lifts for marginal cost-plus-profit may also improve
> the practical economics of air launch across a range of vehicle sizes.
>
> Henry
>
> On 2/16/2015 1:08 PM, Henry Vanderbilt wrote:
>> One addition to Bill's observations here: Range costs at the traditional
>> ground launch ranges don't scale noticeably with launcher size, and can
>> make air launch costs competitive with ground launch at the small end of
>> the payload range.
>>
>> A half-million in range costs is 1% of a $50m F9 launch, but if your
>> target price per launch is $5m it's 10%, and at $1m it's 50%. Given
>> that the aircraft also cost (somewhat) less down at the small end of the
>> range (and also that the pull-up capability Bill mentions gets somewhat
>> easier to obtain) there may be an economic case to be made for
>> air-launch for smallsat launchers.
>>
>> Henry
>>
>> On 2/16/2015 3:18 AM, Bill Claybaugh wrote:
>>> Liam:
>>>
>>> I do not know of any reference but here are some general observations:
>>>
>>> - in general, air launch is more expensive than ground launch (I know
>>> Burt says the opposite, but he is provably wrong).
>>>
>>> - if custom built; air launch drop aircraft are typically more costly
>>> than a ground launch pad for the same size solid rocket.
>>>
>>> - annual O&M costs to maintain flight certification are typically
>>> higher than the same costs for a solid rocket ground launch pad.
>>>
>>> - horizontal drop requires a pull-up maneuver; the lowest mass way to
>>> do that is wings, but all that mass is unneeded for ground launch. The
>>> alternative is to have the drop aircraft pitch up; that requires a
>>> much higher performance aircraft.
>>>
>>> - air launch rockets want to be solids, particularly if horizontally
>>> launched. Feed system complexity and slosh issues during the pull-up
>>> add still more mass to a liquid solution which is not offset by the
>>> increased Isp.
>>>
>>> - most of the additional performance from air launch is in the higher
>>> area ratio of the first stage motor; the velocity imparted by the
>>> aircraft is trivial in comparison.
>>>
>>> - to make air launch economically competitive the aircraft has to have
>>> some other user (e.g. sub-orbital joyrides; carrying large or bulky
>>> cargo); otherwise the O&M cost quickly drives the project to the high
>>> cost, low flight rate corner of the box (Pegasus, for example).
>>>
>>> - the advantages of "any orbit; any time" are largely national
>>> security related; in the absence of such a sponsor / customer there is
>>> very little commercial justification for the higher cost of air
>>> launch. Cheaper to wait for the desired orbit to pass over the launch
>>> pad. (Which, BTW, argues for a single, all azimuth, ground launch pad.)
>>>
>>> Bill
>>>
>>>
>>>
>>> Sent from my iPhone
>>>
>>> On Feb 14, 2015, at 12:38 AM, Liam McQuellin <lmcquellin@xxxxxxxxxxx>
>>> wrote:
>>>
>>>> Hi All,
>>>>
>>>> I am writing a paper and I am looking for a text book that describes
>>>> air launch concepts. Does anyone know of any they could recommend?
>>>>
>>>> Thanks,
>>>>
>>>> Liam McQuellin
>>>> Australian Space Research Institute
>>>
>>>
>>
>>
>
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