LOW EARTH ORBIT PAYLOAD LAUNCH
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to vehicles used to place payloads such as satellites in low earth orbit. The new vehicle uses three stages comprised of a turbofan engine powered aircraft, a ramjet powered aerospacecraft and a rocket booster to place payloads in orbit.
2. Description of Related Art
There are currently in use several methods for launch of earth orbit payloads. These include rocket powered vehicles such as the French Ariane, Russian Proton, Chinese Long March, and various United States rockets. In addition there is the United States Space Shuttle system which is also a rocket powered system. The rocket powered vehicles other than the Space Shuttle have varying degrees of reliability or lack thereof and tend to be expensive as each must be assembled for the launch of a payload into orbit.
In the case of the United States Space Shuttle, the launch vehicle has proven to be reliable once launched; however, the process to prepare for a launch is time consuming and expensive. The Space Shuttle also has some reusable elements for purposes of reducing launch costs. Refurbishment of these reusable elements has proven to be expensive. Part of the Space Shuttle operation includes extensive facilities for launch operations which are located in only one place, Florida.
All of these systems use rockets that require stored propellants either solid or liquid, which includes fuel and oxidizer and does not take advantage of the oxygen available in the atmosphere. Achieving orbital speeds requires tremendous expenditures of propellants. For example, the Space Shuttle carries less than 2% of the gross lift-off weight as payload, with the remainder being mostly propellant and structure. Rockets like the Space Shuttle use tons of propellants every second the engines are functioning. Rocket engines typically require the propellants to be delivered at very high pressure which directly impacts turbomachinery cost, complexity and reliability.
Most of these rocket systems were designed to deliver large, heavy payloads. When used to launch orbital payloads they can be used to position large, heavy satellites in high earth orbits including geosynchronics orbits. However, the high cost and reliability issues inherent in the current systems as previously discussed have inhibited the large scale utilization of space.
Other methods have been proposed as exemplified in the background discussion in U.S. Pat. No. 4.265,416 and by the disclosure in U.S. Pat. No. 4,265,416, granted May 5, 1981 and others such as U.S. Pat. No. 4,802.639, granted Feb. 7, 1989 and U.S. Pat. No. 5,402,965. granted Apr. 4. 1995 which attempt to use horizontal takeoff carrier vehicles as an initial stage for boost of payloads into orbit. In such an approach turbofan engines may be used for a portion of the vehicle flight which allows use of the atmosphere and a reduction in the weight of oxidizer that must be carried. However, in the case of U.S. Pat. Nos. 4,265.416 and 4,802,639, an extensive design for an initial boost phase carrier or booster vehicle and orbiter vehicle is required. These are non-conventional elements involving technical risk regarding both viability and performance costs. In one instance use of a ramjet engine is proposed which technol
ogy for such an application would require development of unproven technology.
In the case of U.S. Pat. No. 5.402.965 use of a proven carrier boost vehicle is disclosed. The system uses a proven
5 aircraft for the initial boost phase. For subsequent phases of flight including atmospheric stages a multistage rocket powered vehicle is disclosed. This again involves the inefficiencies discussed earlier in that rockets must provide their own oxidizer. From this disclosure it also appears that the pay
io load vehicle or refly vehicle must be mounted on the end of a multistage rocket attached under the wing of a commercial aircraft. This system uses non-recoverable rocket boost stages.
The present invention uses a three stage vehicle to launch 15 orbit payloads. The vehicle may also be used as a two or three stage vehicle for conducting experiments in space. The vehicle uses the appropriate aerodynamic vehicle and power source for each stage over its altitude operational range. A conventual turbofan powered aircraft such as a Lockheed 20 C-5 or Antonov AN-124 is used for the horizontal take off and initial boost phase. This uses existing known low risk technology with modification for transport of the second and third stages.
The second stage carried under the wing of the turbofan
25 aircraft is an aerospacecraft which is an ejector ramjet powered stage. The aerospacecraft is dropped from the aircraft and flies to an exo-atmospheric altitude. At this point the vehicle may be used in a space environment for example for conducting experiments in space. If it is desired to
30 position a satellite in low earth orbit, the aerospacecraft carries a rocket booster with payload in its cargo bay. The rocket booster is released from the aerospace craft and boosts the payload such as a satellite into orbit.
35 All of these stages are recoverable and reusable. The aerospacecraft flies back to land on a conventual runway as does the aircraft. The rocket booster releases its payload and deorbits. As it descends in the atmosphere a parachute is deployed and the rocket booster is then recovered by a
w recovery aircraft. The first two stages use engines which allow use of the atmosphere for the fuel oxidizing agent which greatly reduces vehicle weight providing almost an order of magnitude improvement in performance compared to known rocket powered vehicles.
45 SUMMARY OF THE INVENTION
A primary objective of the present invention is to provide a minimum risk technology system for launch of low earth orbit payloads. A further object is to provide a satellite
50 launch system which can launch under varying weather conditions at various sites around the earth. Another object is to maximize the use of the atmosphere for fuel oxidizer for the launch system. A further object is to provide less vehicle induced stress on the payload during the boost to orbit, a
55 relatively softer ride. Another object is to provide flexible ability to replace a single failed satellite in a particular orbit. Another object is to provide a launch system in which all stages are normally reusable with reduced maintenance costs between launches. A further object is to provide a launch
5Q system which can utilize existing airfields as launch sites. In accordance with the description presented herein, other objectives of this invention will become apparent when the description and drawings are reviewed.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 illustrates the operational stages of the orbital launch system.