|
||||||||||
|
The reference mission spacecraft shown at the left weighs
about 120,000 lbs.
That's what we need to get into a parking
orbit at a altitude of about 100 nautical miles. See the spacecraft mass breakdown in section
4.2 for details about where that came from.
ASI 9700026 shows a larger version of this illustration. In this image by Vik Olliver, you're seeing the spacecraft from the back. The spacecraft has its windows pointed toward Earth.
A launcher with payload capacity greater than 60,000 lbs is better. Less is possible, but we're sacrificing mission objectives big time below 120,000 lbs. To avoid on-orbit integration and associated costs, we want to package this in as few launch packages as we reasonably can, unless in the future smaller launchers offer an enormously reduced cost per pound to orbit.
Two launches at 60,000 lbs would be ideal. We should keep options open for up to four such launches.
Functionally, Apollo used two launch packages per flight. They went up on the same Saturn V, but they still had all the weight and cost of on-orbit integration when the Command Module had to separate, turn around, and dock with the Lunar Module.
For the Artemis Project flights, we want to avoid carrying a heavy-weight docking mechanism to the moon and back if we can.
Assume the package is 15 feet in diameter, less than 60 feet long. Telemetry requirements are minimal; we only need enough data to satisfy ourselves that the payload is worth launching and whatever is needed to keep the Range Safety Officer happy.
We would like to mount cameras external to the payload shroud to record the launch from the payload's point of view. This information does not have to be telemetered to the ground in real time, though it would be nice if it could be.
Payload includes cryogenic fuels which must be loaded at the launch site.
On the first launch we have a very wide margin for orbital insertion, but all other launches have to rendezvous with the first.
Orbital inclination accuracy is the major driver for the second and subsequent launches. If the Lunar Transfer Vehicle goes up on the second launch, it will have wide margins for performing the rendezvous with the first launch package. However we don't want to burn fuel adjusting the inclination of the orbit.
If there are more than two launches, the LTV
could be stationed at an Earth orbit support facility such as the
show to the right. Then we can use the LTV as a tug to
shepherd the rest of the spacecraft together at the LEO support
facility.
The estimate of 120,000 lbs of payload weight to Earth orbit does not include the weight of th Earth Orbit Support Facility. We have not completed a detailed analysis of this little space station, but an initial guess is that the support facility will add up to on the order of 50,000 lbs. That includes the assembly cradle and rebotics, but not the crew vehicles.
|
|
|
