| |
 |
|
|
Science Forum Index » Space Forum » Tiny dancer...
Page 1 of 1
|
| Author |
Message |
| Williamknowsbest... |
 Posted: Sun May 04, 2008 9:56 am |
|
|
|
Guest
|
Named after an Elton John song this vehicle consists may be configured
in three ways.
The first way is one flight article with an upper stage.
The second way is three flight articles operating as two stages, with
the possibility of adding an upper stage, making it a three stage
system.
The third way is seven flight articles operating as three stages, with
the possibility of adding an upper stage making it a four stage
system.
A pumpset from an RL10 engine s adapted to form a small hydrogen/
oxygen aerospike engine 1.52 m in diameter. This is at the base of a
12 meter long tank shaped like a minature version of the External Tank
but someone longer relative to its diameter. The oxygen tank is up
front and carries 6,071 kg of oxidizer in its 3 meter length. The
hydrogen tank is behind it, 7.9 meters long carrying 1,011 kg of
fuel. The entire system masses 8,333 kg with 1,250 kg of structure.
The engine produces 15,000 kgf at lift off and has an average specific
impulse during ascent of 440 seconds.
The tank's nose is eqiupped with a thermal protection system capable
of sustaining re-entry. It also is equipped with strakes that house
foldaway wings that deploy after re-entry, once the stage slows to
subsonic speeds so it may be picked up by a tow plane near the re-
entry point and towed back to the launch center after each flight.
In line is a second stage built around the same pump hardware. Fuel
flows are reduced by a factor of five, so thrust is reduced by this
factor to 3,000 kgf. This stage consists of an aerospike with a tps
built around the base, rather than the nose. The stage consists of
two spherical tanks forward of the aerospike engine with tps.
The smaller forward tank is is 1.09 meters in diameter and holds 776
kg of liquid oxygen. The larger tank aft is 1.52 meters in diameter
and holds 129 kg of liquid hydrogen. Total stage weight is 225 kg.
The upper stage carries up to 365 kg of payload behind a nose cone
that can open into three sections and reclose after ejecting the
payload.
The orbiter is capable of deorbiting and executing a powered touchdown
near the launch center along the lines of the DC-X vehicle. The
upper stage has the same diameter as the booster, and clamps hold
landing gear to a ring behind the nose TPS of the booster. The
landing gear thus form an inter-stage support system during launch.
The are re-tracted during re-entry, and are deployed again upon
touchdown. The same high pressure helium system that drives the pump
sets also drive the APU that powers the landing gear.
The stage forms a cone with a 20 degree opening angle and a spherical
nose 0.8 meters in diameter at the top.and the entire stage length is
4.0 meters in length.
A three element system consisting of two booster tanks flanking a
central booster tank just described. The outer booster tanks feed
propellant to the central tank, forming a two stage system. This can
put 1,200 kg into the same orbit as the previous system. It can also
be configured to launch the upper stage to carry 365 kg on an
interplanetary or cislunar trajectory - with recovery of all stages.
A seven element system consisting of seven four booster tanks flanking
the three boosters just described. The four boosters feed propellant
to the two outboard boosters creating a three stage system from the
seven elements. This system can put 4,000 kg into LEO. It can also
put 1500 kg stage on the lunar surface - with a 365 kg payload with
return of all stages.
Each stage will cost $2.5 million to build. There are 12 elements in
the development program, so that's $28 million. Another $12 million
for operations through first flight. A total budget of $30 million.
With this vehicle, all of the Apollo landing sites may be re-visited,
and samples returned to Earth, along with HDTV. Once that is
completed, and additional science is done, additional landing sites,
the ones not visited by Apollo but slated for later missions, will
also be visited. After a dozen successful flights, the system will
then be sent to Mars.
For a Mars flight the system is lofted into a 2 year Mars free-return
trajectory. That is,the central stage is boosted into an orbit that
has an apehelion of 325.1 million kilometers. This brings that
booster stage back to Earth in precisely 2 years. Both the booster
and the lander are equipped with communications gear and HDTV cameras
during the flight, so a variety of views and inspections can be
carried out in transit.
The lander aerobrakes and lands by rocket power burning very little of
its propellant. The rover oprates as it did on the moon, returning
with the vehicle, and carrying a sample of Mars material back. The
lander loiters on Mars and then returns to Earth along with the
booster rocket. Both re-enter Earth's atmosphere. The booster is
recovered by tow plane. The lander executes a powered touchdown near
the launch center.
This will serve as a test bed for a variety of piloted missions and
systems, built on a larger scale.
The 4,000 kg payload will be adapted to a 6 passenger orbital run-
about. Two crew members four paying passengers, attaining Low Earth
Orbit. Another 4,000 kg 'tanker' stage docks with the run-about once
on orbit, and boosts both to a lunar-free return trajectory for a
lunar flyby.
A larger system with each flight element massing 1,000,000 kg and
RS-68 pumpset replacing the RL-10 pumpset in the aerospike engine -
increases payloads proportionately - permiting a wide range of larger
payloads to be flown. Including a piloted expedition to the lunar
surface, and to Mars.
.. |
|
|
| Back to top |
|
| |
|
Page 1 of 1
All times are GMT - 5 Hours
The time now is Mon Jul 07, 2008 10:19 am
|
|
