In theory at least, a low-cost nanosat launcher could spread carrier aircraft annual O&M costs over a considerably higher number of flights than Pegasus ever flew. (Market-dependent, of course.)
Also, yes, a military fighter isn't a good choice for low O&M costs, but it isn't necessarily the only option - a considerably smaller rocket than Pegasus would allow for either a considerably smaller carrier aircraft than Orbital's L-1011 (with a winged rocket) or a modestly smaller carrier flying lightly loaded enough that it has useful pull-up performance.
And in general, the option for a smaller commercial aircraft as carrier opens up scope for a relatively modern aircraft with considerably lower O&M costs than a 1011. (I understand relatively high O&M costs are one reason not many 1011's are flying anymore.)
As for your ideas about doing surface launch of relatively small vehicles away from the established coastal launch ranges and their fees, I've had some ideas along those lines also. (Careful readers may note I haven't said I *prefer* air-launch, just that there are arguments in its favor.) The biggest hurdle seems to me regulatory. But then, being the first to take on a major regulatory unknown isn't necessarily the thing to make investors feel all warm and fuzzy.
Henry On 2/16/2015 4:59 PM, Bill Claybaugh wrote:
Reading between the lines, some: For cube sats, specifically, there is a current USG program to investigate a small solid rocket launched from a fighter aircraft. This is no doubt technically feasible; it seems to me unlikely that it will be lower cost than a ground launch: If an L-1011 has annual O&M costs higher than those of a solid rocket launch pad--as I implied earlier--then based on direct knowledge of the numbers I conclude it unlikely that a used military fighter is going to have any lower costs, particularly given that the pad O&M for a solid rocket pad at this scale is approaching zero. (Supersonic aircraft have O&M costs about an order of magnitude higher than subsonic aircraft, per pound of dry mass.) I concur that range costs--if paid--become a significant issue for a dedicated cubesat launcher, however, I see no reason to pay such costs: we are talking here about something smaller than a V-2.... There are multiple business arrangements that can avoid range costs, at this scale. Bill Sent from my iPhone On Feb 16, 2015, at 3:08 PM, Henry Vanderbilt <hvanderbilt@xxxxxxxxxxxxxx> 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