huntting@boulder.Colorado.EDU (Bradley Enoch Huntting) (02/09/88)
It occured to me the other day that when satalites launched from within the U.S., they are put into a transfer orbit which is inclined about 20 deg from the plane of the equator. This means that the net change in velocity nessary to place the payload into geosyncronous orbit (sum of the instantainious acceleration nessary to attain transfer orbit (~10.1 km/s) plus the instantainious acceleration nessary to bump the object from transfer to geosyncronous orbit (~1.45 km/s if launched from the equator, or ~4.39km/s if launched from 20 deg latitude) is higher by ~3km/s! That's a 26% increse! Add to this the fact that the mass of the delivery system increases with the net velocity change. Now it seems to me that lightening the workload by 20% would significantly decreace the cost of delivery! So why doesn't anyone launch from the equator? The climate in the south pacific or indian ocean is comparable to that of the cape. There are several Indoneasian islands near Syngapore which could be used. I understand that a government might have reservations about investing the nessary capitol for a launch facility in a forign countryr. However a private enterprise would be able to deliver satelites for a significant discount over what NASA could. Esspecially once one considers that near Syngapore there is a well educated workforce which one doesn't have to pay in $! So what I'm asking is: why hasn't someone with money thought of this? And if they have, what success have they had? -brad e huntting huntting@boulder.colorado.edu ...!hao!boulder!huntting please excuse the spelling. Hope I don't sound to neo-colonialist.
des@jplpro.JPL.NASA.GOV (David Smyth) (02/10/88)
Many people who have the choice do - they launch on Ariane from Honduras. We don't have that choice, of course. We don't need it, we have the Shuttle!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
mac@idacrd.UUCP (Bob McGwier) (02/11/88)
From article <1264@devvax.JPL.NASA.GOV>, by des@jplpro.JPL.NASA.GOV (David Smyth): > Many people who have the choice do - they launch on Ariane from > Honduras. We don't have that choice, of course. We don't need > it, we have the Shuttle!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! BULL, we have as many possibilities for near equatorial launch if we pursued them, it is just not apparent that it would be cost effective. The launch site for Ariane is in the French state, French Guiana in the town of Kourou. Bob
fiddler%concertina@Sun.COM (Steve Hix) (02/11/88)
In article <1264@devvax.JPL.NASA.GOV>, des@jplpro.JPL.NASA.GOV (David Smyth) writes: > Many people who have the choice do - they launch on Ariane from > Honduras. We don't have that choice, of course. We don't need > it, we have the Shuttle!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! So who's launching Ariane from Honduras? I'm sure the French would like to find out who's been swiping their rockets. :}
roger@telesoft.UUCP (Roger Arnold @prodigal) (02/12/88)
In article <1505@boulder.Colorado.EDU>, huntting@boulder.Colorado.EDU (Bradley Enoch Huntting) writes: > It occured to me the other day that when satalites launched from within the > U.S., they are put into a transfer orbit which is inclined about 20 deg from > the plane of the equator. This means that the net change in velocity nessary > to place the payload into geosyncronous orbit (sum of the instantainious > acceleration nessary to attain transfer orbit (~10.1 km/s) plus the > instantainious acceleration nessary to bump the object from transfer to > geosyncronous orbit (~1.45 km/s if launched from the equator, or ~4.39km/s > if launched from 20 deg latitude) is higher by ~3km/s! That's a 26% increse! > [..] Whoa! I don't know where you got that 4.39 km/sec figure, but it's way off. (Actually, I can guess: it sounds like what one might come up with by figuring the plane change first, in LEO, rather than at GEO). There is definitely a penalty for launching from higher latitudes, but it's not nearly that bad. (Figure, figure). Uhm, the back of the envelope numbers I get--taking your 10.1 km/s and 1.45 km/s as correct--is about 1.65 km/s for the appogee burn from a launch at 20 deg. That's still a significant penalty, but not unbearable. The vector diagram for the two appogee burns looks something like this (pardon my ascii): ^ |\ | \ | \ 1.45 km/s | \ 1.65 km/s | \ | \ ^ \ | 20 ^ | deg./ 1.55 km/s | / | / 1.55 km/s | / | / o - Roger Arnold ..ucsd!telesoft!roger
kcarroll@utzoo.uucp (Kieran A. Carroll) (02/12/88)
The following is quoted from a rather timely article
in the February, 1988 >Space World< issue, entitled
"The Pros and Cons of Launch Sites," by Lawrence Suid.
The context is a discussion of the choice of Cape Canveral
as the launch site for the Apollo moon program:
"...the decision to locate the Apollo launch facilities
at the Cape came only after deliberation and debate...
Christmas Island in the central Pacific was a contender
because of its location near the equator...launching...
from an equatorial location could take advantage of the Earth's
rotational velocity...Most important, launching from an
equatorial base avoided the costly dogleg technique, a
prerequisite for placing rockets into an equatorial orbit
from a site such as Cape Canaveral...There were also
disadvantages in locating Apollo facilities outside the
United States. Construction costs would be about 100%
higher. NASA would have logistics problems and face the
uncertainties of setting up an American base on foreign
soil."
It seems to me that most near-equatorial countries
are either politically unstable, or lack much industrial
infrastructure, or both. Lack of infrastructure will
increase the costs of both the initial construction
of facilities (launch, assembly and checkout, employees'
housing, etc.), and of operations (shipping satellites,
boosters, rocket fuel, etc., from several thousand miles
away). This additional cost need not force the decision
against an equatorial launch site, of course; the French
are doing just fine in South America. However, they
undoubtedly had some infrastructure in place before Ariane
came along.
Kieran A. Carroll @ U of Toronto Aerospace Institute
{allegra,ihnp4,decvax,pyramid}!utzoo!kcarroll
--
Kieran A. Carroll @ U of Toronto Aerospace Institute
{allegra,ihnp4,decvax,pyramid}!utzoo!kcarroll