阅读说明：本技术 一种利用高原助推发射的单级入轨空天飞行技术方法 (Single-stage orbit-entering aerospace flying technical method utilizing plateau boosting launching ) 是由 赵吉松 张汉清 王泊乔 张金明 朱航标 于 2020-04-24 设计创作，主要内容包括：本发明公开了一种利用高原助推发射的单级入轨空天飞行技术方法,该方法通过在高原上修建助推发射轨道,利用助推发射轨道的助推力将助推发射平台和RBCC组合动力单级入轨空天飞行器的组合体加速至最大助推发射速度,然后空天飞行器与助推发射平台分离并起飞,接着空天飞行器利用自身的RBCC组合动力沿燃耗最优上升轨迹加速飞行直至入轨,与此同时,助推发射平台在助推发射轨道的制动力的作用下制动减速,直至速度降为0。本发明方法能够显著减小单级入轨空天飞行器上升过程消耗的燃料,从而提高飞行器的入轨质量,最终有利于提高飞行器的运载能力和降低飞行器各分系统的设计难度。(The invention discloses a single-stage in-orbit aerospace flying technical method utilizing plateau boosting launching, which comprises the steps of building a boosting launching track on a plateau, accelerating a combination body of a boosting launching platform and a single-stage in-orbit aerospace vehicle of RBCC combined power to the maximum boosting launching speed by utilizing boosting force of the boosting launching track, separating the aerospace vehicle from the boosting launching platform and taking off, accelerating the aerospace vehicle to enter the orbit along the optimal combustion-consumption ascending track by utilizing the RBCC combined power of the aerospace vehicle, and braking and decelerating the boosting launching platform under the action of braking force of the boosting launching track until the speed is reduced to 0. The method can obviously reduce the fuel consumed in the ascending process of the single-stage orbit-entering aerospace vehicle, thereby improving the orbit-entering quality of the aerospace vehicle, and finally being beneficial to improving the carrying capacity of the aerospace vehicle and reducing the design difficulty of each subsystem of the aerospace vehicle.)

1. A single-stage rail-entering aerospace flying technical method utilizing plateau boosting launching is characterized by comprising the following steps:

step 1, paving a boosting launching track on a plateau with the altitude of more than 4000 meters;

step 2, accelerating the boosting launching platform and the single-stage in-orbit aerospace craft from rest by using the boosting force of the boosting launching track, and separating and taking off the single-stage in-orbit aerospace craft from the boosting launching platform when accelerating to the maximum boosting launching speed;

step 3, after the single-stage in-orbit aerospace craft takes off, accelerating the flight along the ascending track of the most fuel-saving fuel by using the RBCC combined power of the aircraft until the single-stage in-orbit aerospace craft enters the target track;

step 4, after the single-stage in-orbit aerospace vehicle is separated from the boosting launching platform, the boosting launching platform brakes and decelerates under the action of the braking force of the boosting launching track until the speed of the boosting launching platform is reduced to 0;

the length calculation method of the boosting launching track comprises the following steps:

taking the positions of the boosting launching platform and the single-stage in-orbit aerospace craft when the boosting launching platform and the single-stage in-orbit aerospace craft are static as the starting points of the boosting launching tracks, taking the positions of the boosting launching platform and the single-stage in-orbit aerospace craft as separation points when the boosting launching platform and the single-stage in-orbit aerospace craft are accelerated to the maximum boosting launching speed, and taking the position of the boosting launching platform when the speed of the boosting launching platform is reduced to 0 as the terminal point of the boosting launching tracks;

and regarding the space between the starting point and the separation point as a boosting acceleration section, wherein the mass center motion equation of the combination of the boosting launching platform and the single-stage in-orbit aerospace vehicle at the boosting acceleration section is as follows:

wherein v is the speed of the aircraft; t is time; t is_BoostThe boosting force m applied to the boosting accelerating section for boosting the launching platform_allFor boosting the total mass, m, of the combination of launch platform and single-stage in-orbit aerospace vehicle_all＝m₀+m_Bus，m₀Is the initial mass, m, of a single-stage in-orbit aerospace vehicle_BusTo boost the mass of the launch platform; c_DIs a coefficient of resistance; rho_PIs the atmospheric density on the plateau of step 1; s_refIs a reference area of aerodynamic force; x is the displacement of the boosting launching platform along the track direction;

and regarding the space between the separation point and the terminal point as a braking section, wherein in the braking section, the mass center motion equation of the boosting launching platform is as follows:

wherein, T_BreakThe braking force applied to the boosting launching platform at the braking section is realized;

and respectively carrying out numerical integration on the two equation sets to obtain the lengths of the boosting launching track in the boosting accelerating section and the braking section, and adding the lengths to obtain the total length of the boosting launching track.

2. The technical method for single-stage in-orbit aerospace flight by using plateau boosting launching as claimed in claim 1, wherein the boosting force applied to the boosting and accelerating section of the boosting and launching platform is the same as and opposite to the braking force applied to the braking section of the boosting and launching platform.

3. The single-stage in-orbit aerospace flight technical method by utilizing plateau boosting launching as claimed in claim 1, wherein the maximum boosting launching speed in step 2 is calculated by the following formula:

wherein v is_Boost,maxTo boost the launch velocity, q_maxIs the maximum dynamic pressure, rho, which can be borne by a single-stage orbit aerospace vehicle_PIs the atmospheric density on the plateau of step 1.

4. The single-stage in-orbit aerospace flight technical method by using plateau boosting launching as claimed in claim 1, wherein the calculation process of the most fuel-saving ascending trajectory in step 3 is as follows:

in a longitudinal plane, a system of differential equations describing the motion of the mass center of the single-stage orbit aerospace vehicle is as follows:

wherein r is the distance between the mass center of the aircraft and the geocentric, t is time, v is the speed of the aircraft, gamma is the track angle, theta is the voyage angle, m is the mass of the aircraft, P is the thrust of the RBCC combined power of the single-stage in-orbit aerospace aircraft, α is the flight attack angle, C is the thrust of the RBCC combined power of the single-stage in-orbit aerospace aircraft_DIs a coefficient of resistance; ρ is the atmospheric density; s_refIs a reference area of aerodynamic force; mu is an earth gravity constant; c_LIs the coefficient of lift; i is_spFuel specific impulse for RBCC combined power; g_SLIs sea level gravitational acceleration;

the initial conditions of the ascending track of the single-stage in-orbit aerospace vehicle are as follows:

wherein, t₀Is the initial time of the rising trajectory; r is₀Is the initial ground center distance, r, of the aircraft₀＝R_e+h_P，R_eIs the radius of the earth, h_PThe altitude of the plateau of step 1; theta₀Is an initial range angle; v. of₀To take-off initial velocity, v₀＝v_Boost,max，v_Boost,maxThe maximum boosting launching speed is obtained; gamma ray₀Is the initial track angle; m is₀The initial mass of the single-stage in-orbit aerospace vehicle;

the tail end conditions of the ascending track of the single-stage in-orbit aerospace vehicle are as follows:

wherein, t_fThe time for entering the target track is the track entering time; r is_oIs the center distance of the ground at the point of track entry, r_o＝R_e+h_o，R_eIs the radius of the earth, h_oIs the target track height; v. of_oIs the target track speed; gamma ray_oIs the track angle of the track entry point;

in the ascending process of the single-stage orbit-entering aerospace vehicle, dynamic pressure constraint is considered as follows:

wherein q (t) is the flight dynamic pressure of the aircraft during ascent, q_maxThe dynamic pressure is the maximum dynamic pressure which can be borne by a single-stage orbit aerospace vehicle;

the most fuel-saving ascending track is equivalent to the maximum residual mass when the aircraft reaches the target track, and then the objective function J of the single-stage in-orbit aerospace vehicle ascending track optimization problem is as follows:

min J＝-m(t_f)

and solving the optimization problem of the ascending track of the single-stage orbit-entering aerospace vehicle described by the five equations to obtain the maximum orbit-entering quality of the single-stage orbit-entering aerospace vehicle.

Technical Field

The invention relates to a single-stage in-orbit aerospace flying technical method utilizing plateau boosting launching, and belongs to the technical field of aircraft design.

Background

The single-stage rail-entering aerospace flight scheme is always taken as the development direction and pursuit target of a human aerospace transportation system and is highly valued. In recent years, with the development of an air-breathing propulsion technology, researchers at home and abroad carry out intensive research on a single-stage orbit-entering aerospace flight technical scheme Based on Rocket-Based Combined Cycle (RBCC). At present, one difficulty of the technical scheme of the RBCC combined power single-stage rail-entering aerospace flight is that the fuel quantity consumed in the ascending process of an aircraft is too large, and the residual mass in the rail entering process is too small, so that the mass of the aircraft subsystems and the mass of the effective load, such as the structure, the engine, the thermal protection system and the like which can be distributed to the aircraft, are too small, and the design difficulty of each subsystem of the aircraft is large, the carrying capacity is small, or even the carrying capacity is not high. Obviously, if the fuel consumption of the single-stage rail-entering aerospace vehicle in the ascending stage can be reduced, namely the rail-entering residual mass of the aircraft is improved, the design difficulty of each subsystem of the single-stage rail-entering aerospace vehicle is reduced, and the carrying capacity of the aircraft is improved. The main disadvantages of the RBCC combined power are poor performance of a low-speed section and high fuel consumption. The ground boosting launching technology is an effective way for reducing fuel consumption of the ascending section of the RBCC combined power single-stage rail-entering aircraft; but because of the large atmospheric density on the ground, the ground boosting launch velocity cannot be too great, otherwise the dynamic pressure would exceed the bearing capacity of the aircraft.

Considering that the altitude of the plateau is higher and the atmosphere is thin, the aircraft is allowed to be accelerated to a higher launching speed under the same maximum dynamic pressure constraint compared with a common launching field close to the altitude of the sea, so that the fuel consumption of the ascending stage of the single-stage rail-entering aircraft can be further reduced. In addition, the atmospheric density on the plateau is small, so that the air resistance at the same speed in the boosting acceleration process is smaller, and the air-borne vehicle can be accelerated more easily. In view of the advantages of the plateau boosting launch and the vast Qinghai-Tibet plateau of China, the invention provides a novel technical scheme of single-stage in-orbit aerospace flight based on the plateau boosting launch.

Disclosure of Invention

The technical problem to be solved by the invention is as follows: the method can reduce the fuel quality required to be consumed in the ascending process of the RBCC combined power single-stage rail-entering aerospace craft, thereby improving the proportion of the rail-entering quality of the aerospace craft to the total quality of the aerospace craft.

The invention adopts the following technical scheme for solving the technical problems:

a single-stage rail-entering aerospace flying technical method utilizing plateau boosting launching comprises the following steps:

step 1, paving a boosting launching track on a plateau with the altitude of more than 4000 meters;

step 2, accelerating the boosting launching platform and the single-stage in-orbit aerospace craft from rest by using the boosting force of the boosting launching track, and separating and taking off the single-stage in-orbit aerospace craft from the boosting launching platform when accelerating to the maximum boosting launching speed;

step 3, after the single-stage in-orbit aerospace craft takes off, accelerating the flight along the ascending track of the most fuel-saving fuel by using the RBCC combined power of the aircraft until the single-stage in-orbit aerospace craft enters the target track;

step 4, after the single-stage in-orbit aerospace vehicle is separated from the boosting launching platform, the boosting launching platform brakes and decelerates under the action of the braking force of the boosting launching track until the speed of the boosting launching platform is reduced to 0;

the length calculation method of the boosting launching track comprises the following steps:

taking the positions of the boosting launching platform and the single-stage in-orbit aerospace craft when the boosting launching platform and the single-stage in-orbit aerospace craft are static as the starting points of the boosting launching tracks, taking the positions of the boosting launching platform and the single-stage in-orbit aerospace craft as separation points when the boosting launching platform and the single-stage in-orbit aerospace craft are accelerated to the maximum boosting launching speed, and taking the position of the boosting launching platform when the speed of the boosting launching platform is reduced to 0 as the terminal point of the boosting launching tracks;

and regarding the space between the starting point and the separation point as a boosting acceleration section, wherein the mass center motion equation of the combination of the boosting launching platform and the single-stage in-orbit aerospace vehicle at the boosting acceleration section is as follows:

wherein v is the speed of the aircraft; t is time; t is_BoostThe boosting force m applied to the boosting accelerating section for boosting the launching platform_allFor boosting the total mass, m, of the combination of launch platform and single-stage in-orbit aerospace vehicle_all＝m₀+m_Bus，m₀Is the initial mass, m, of a single-stage in-orbit aerospace vehicle_BusTo boost the mass of the launch platform; c_DIs a coefficient of resistance; rho_PIs the atmospheric density on the plateau of step 1; s_refIs a reference area of aerodynamic force; x is the displacement of the boosting launching platform along the track direction;

and regarding the space between the separation point and the terminal point as a braking section, wherein in the braking section, the mass center motion equation of the boosting launching platform is as follows:

wherein, T_BreakThe braking force applied to the boosting launching platform at the braking section is realized;

and respectively carrying out numerical integration on the two equation sets to obtain the lengths of the boosting launching track in the boosting accelerating section and the braking section, and adding the lengths to obtain the total length of the boosting launching track.

In a preferred embodiment of the present invention, the boosting force applied to the boosting and accelerating section of the boosting and launching platform is the same as and opposite to the braking force applied to the braking section of the boosting and launching platform.

As a preferred scheme of the present invention, the maximum boost launching speed in step 2 is calculated by the following formula:

wherein v is_Boost,maxTo boost the launch velocity, q_maxIs the maximum dynamic pressure, rho, which can be borne by a single-stage orbit aerospace vehicle_PIs the atmospheric density on the plateau of step 1.

As a preferred embodiment of the present invention, the calculation process of the fuel-saving ascending trajectory in step 3 is:

in a longitudinal plane, a system of differential equations describing the motion of the mass center of the single-stage orbit aerospace vehicle is as follows:

wherein r is the distance between the mass center of the aircraft and the geocentric, t is time, v is the speed of the aircraft, gamma is the track angle, theta is the voyage angle, m is the mass of the aircraft, P is the thrust of the RBCC combined power of the single-stage in-orbit aerospace aircraft, α is the flight attack angle, C is the thrust of the RBCC combined power of the single-stage in-orbit aerospace aircraft_DIs a coefficient of resistance; ρ is the atmospheric density; s_refIs a reference area of aerodynamic force; mu is an earth gravity constant; c_LIs the coefficient of lift; i is_spFuel specific impulse for RBCC combined power; g_SLIs sea level gravitational acceleration;

the initial conditions of the ascending track of the single-stage in-orbit aerospace vehicle are as follows:

wherein, t₀Is the initial time of the rising trajectory; r is₀Is the initial ground center distance, r, of the aircraft₀＝R_e+h_P，R_eIs the radius of the earth, h_PThe altitude of the plateau of step 1; theta₀Is an initial range angle; v. of₀To take-off initial velocity, v₀＝v_Boost,max，v_Boost,maxThe maximum boosting launching speed is obtained; gamma ray₀Is the initial track angle; m is₀The initial mass of the single-stage in-orbit aerospace vehicle;

the tail end conditions of the ascending track of the single-stage in-orbit aerospace vehicle are as follows:

wherein, t_fFor entering the target track at the time of entering the trackTime; r is_oIs the center distance of the ground at the point of track entry, r_o＝R_e+h_o，R_eIs the radius of the earth, h_oIs the target track height; v. of_oIs the target track speed; gamma ray_oIs the track angle of the track entry point;

in the ascending process of the single-stage orbit-entering aerospace vehicle, dynamic pressure constraint is considered as follows:

wherein q (t) is the flight dynamic pressure of the aircraft during ascent, q_maxThe dynamic pressure is the maximum dynamic pressure which can be borne by a single-stage orbit aerospace vehicle;

the most fuel-saving ascending track is equivalent to the maximum residual mass when the aircraft reaches the target track, and then the objective function J of the single-stage in-orbit aerospace vehicle ascending track optimization problem is as follows:

min J＝-m(t_f)

and solving the optimization problem of the ascending track of the single-stage orbit-entering aerospace vehicle described by the five equations to obtain the maximum orbit-entering quality of the single-stage orbit-entering aerospace vehicle.

Compared with the prior art, the invention adopting the technical scheme has the following technical effects:

1. the invention provides a technical method for single-stage orbit-entering aerospace flight by using RBCC combined power for boosting and launching of a boosting and launching track on a plateau, which can obviously reduce fuel consumed by an ascending section of a single-stage orbit-entering aircraft and improve the orbit-entering quality of the aircraft, thereby being beneficial to improving the carrying capacity of the aircraft and reducing the design difficulty of various subsystems of the aircraft (realized by improving the quality distribution of various subsystems of the aircraft).

2. Compared with the conventional launching mode of accelerating takeoff from a launching field at the height close to the sea level by means of self power, the method can improve the rail-entering mass percentage of the RBCC combined power single-stage rail-entering aircraft from 26.38% to 30.48% under the same dynamic pressure constraint; since the carrying ratio of most current carrier rockets is only about 1.5-2.5%, even 1% improvement is very considerable.

Drawings

FIG. 1 is a schematic diagram of a plateau boosting launching single-stage in-orbit aerospace flying technique method.

FIG. 2 is a graph of the speed of a booster launch platform over time in an embodiment of the present invention.

FIG. 3 is a graph of the position of the booster launch platform as a function of time in an embodiment of the present invention.

FIG. 4 is a plot of altitude versus time for a single-stage in-orbit aircraft burnup optimization trajectory in an embodiment of the present invention.

FIG. 5 is a plot of speed over time for a single-stage in-orbit aircraft burn-up optimization trajectory, in accordance with an embodiment of the present invention.

FIG. 6 is a mass versus time plot of a burn-up optimum trajectory for a single-stage on-track aircraft in an embodiment of the present invention.

Detailed Description

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are illustrative only for the purpose of explaining the present invention, and are not to be construed as limiting the present invention.

The invention provides a method for accelerating a combination of a launching platform and a RBCC combined power single-stage in-orbit aerospace craft to a higher speed by using a boosting launching track on a plateau, then separating the aerospace craft from the launching platform and taking off, and then accelerating the aerospace craft to fly along a combustion optimal ascending track by using the RBCC combined power of the aerospace craft until the aerospace craft enters a target track. Taking the Qinghai-Tibet plateau of China as an example, the altitude of different areas is 3000-7000 meters, the average altitude is more than 4000 meters, and the amplitude is broad, thereby providing good and unique geographic resources for building the boosting launching boosting acceleration orbit.

As shown in fig. 1, the scheme of the invention is as follows: (1) building a boosting launching track 1 on a plateau; (2) accelerating a boosting launching platform 2 and a single-stage in-orbit aerospace vehicle 3 from a standstill (at A in figure 1) by using the boosting force of a track 1; (3) when accelerating to a larger speed (at B in figure 1), the single-stage in-orbit aerospace vehicle 3 is separated from the boosting launching platform 2 and takes off; (4) the single-stage in-orbit aerospace vehicle 3 accelerates along the ascending track 4 of the most fuel-saving fuel by using the RBCC combined power of the single-stage in-orbit aerospace vehicle until entering a target track 5; (5) at the same time, the booster launching platform 2 is braked and decelerated by the braking force of the track until the speed drops to 0 (at C in fig. 1).

The key parameters of the scheme of the invention are as follows:

(1) boost launch velocity

The atmosphere on plateaus is rarefied relative to sea level, thus allowing the aircraft to be accelerated to greater launch speeds with the same dynamic pressure constraints; and because the air on the plateau is thin, the air resistance received by the aircraft in the acceleration process is smaller, so that the air-borne aircraft can be accelerated more easily on the plateau.

For a given maximum dynamic pressure constraint, the maximum boost launch velocity allowed for the aircraft is

Wherein: q. q.s_maxMaximum dynamic pressure, ρ, that the aircraft can withstand_PIs the atmospheric density on plateau.

Taking the maximum dynamic pressure q_max160kPa, altitude h of plateau_P5000m, corresponding to an atmospheric density ρ_P＝0.74kg/m³Substituting it into equation (1) can solve v_Boost,max＝659.21m/s。

(2) Length of boosting launching track

The boosting force of the track is adopted to boost and accelerate the aircraft. Assuming that the boosting launching orbit is a straight orbit, the mass center motion equation set of the boosting launching platform and the aircraft combination body in the boosting accelerating section is as follows:

wherein: v is the speed of the aircraft; t is time; t is_BoostThe boosting force of the boosting accelerating device is provided; m is_allFor boosting the total mass, m, of the combined launch platform and aircraft_all＝m₀+m_Bus，m₀Is the initial total mass, m, of a single-stage in-orbit aircraft_BusTo boost the mass of the launch platform; c_DIs a coefficient of resistance; rho_PAtmospheric density on plateau; s_refIs a reference area of aerodynamic force; and x is the displacement of the acceleration platform along the track direction.

When the single-stage in-orbit aircraft is separated from the boosting launching platform and launched for takeoff, the launching platform can still be braked by the boosting force. Compared with the boosting acceleration section, the boosting force is only required to be reversed.

In the braking section, the mass center motion equation of the boosting launching platform is as follows (ignoring the pneumatic resistance of the platform):

wherein: t is_BreakTo launch the braking force experienced by the platform.

And (3) sequentially carrying out numerical integration on the equation (2) and the equation (3) to obtain the lengths of the accelerating section and the braking section of the boosting launching track, and accumulating the lengths to obtain the total length of the boosting launching track.

As an example, the altitude h of the plateau is selected here_P5000 m; initial total mass m of single-stage in-orbit aircraft₀200000 kg; mass m of boosting launching platform_Bus＝0.2m₀(ii) a Boosting force T of boosting launching track_Boost＝3m₀g_SL，g_SLIs sea level gravitational acceleration; after the single-stage in-orbit aircraft is separated from the boosting launching platform and takes off, the braking force of the boosting launching track to the boosting launching platform is the same as the boosting force of the accelerating section, namely T_Break＝T_Boost. The length of the desired booster launch trajectory can be solved by substituting these parameters into equations (2) and (3) and numerically integrating the system of equations as shown in table 1. The velocity of the boosting launching platform and the displacement of the launching platform on the boosting launching track are respectively shown in fig. 2 andas shown in fig. 3. It can be seen that under the parameters of the embodiment, the single-stage on-orbit aircraft can be accelerated to 659.21m/s from a static state within 30.6s only by building a boosting launching orbit with the length of 12.31km on the plateau.

TABLE 1 Booster launch track Length for plateau boost launch

(3) Performance and advantages of plateau boost launch

In order to analyze the performance advantages of the single-stage orbit-entering aerospace vehicle launched by using the plateau boosting compared with the conventional single-stage orbit-entering aerospace vehicle, the ascending locus of the aerospace vehicle needs to be optimized, and the ascending locus of the most fuel-saving aerospace vehicle is solved. In the longitudinal plane, the system of differential equations describing the motion of the aerospace vehicle's center of mass is:

wherein mu is the gravitational constant of the earth, mu is 3.986009 × 10¹⁴m³/s²；C_LIs the coefficient of lift; c_DIs drag coefficient, α is flight angle of attack (rad), r is the distance (m) from the centroid of the aircraft to the geocenter, v is the speed (m/S) of the aircraft relative to the earth, theta is range angle (rad), gamma is track angle (rad), and S is_refReference area (m) for aerodynamic force²) (ii) a m is the mass (kg) of the aircraft; ρ is atmospheric density (kg/m)³) (ii) a P is the thrust (N) of the combined power propulsion system of the single-stage in-orbit aircraft; i is_spFuel specific impulse(s) for an RBCC combined power propulsion system; g_SLIs the sea level gravity acceleration (m/s)²)，g_SL＝9.8m/s²。

The initial conditions of the ascending trajectory of the aerospace vehicle are as follows:

wherein: t is t₀In the ascending trackAn initial time; r is₀Is the initial ground center distance, r, of the aircraft₀＝R_e+h_P，R_eIs the radius of the earth, h_PAltitude at the plateau; theta₀Is an initial range angle; v. of₀Is the initial velocity, v₀＝v_Boost,max，v_Boost,maxThe maximum boosting launching speed is obtained; gamma ray₀Is the initial track angle; m is₀Is the initial mass.

The terminal conditions of the ascending trajectory of the aerospace vehicle are as follows:

wherein: t is t_fIs the time to enter the track; r is_oIs the center distance of the ground at the point of track entry, r_o＝R_e+h_o，R_eIs the radius of the earth, h_oIs the target track height; v. of_oIs the target orbital velocity (relative to the earth), γ_oIs the track angle of the point of approach.

Path constraints such as dynamic pressure, overload, hot spots and the like need to be considered in the ascending process of the aerospace vehicle, and the three constraints are actually relevant. For simplicity, only dynamic pressure constraints are considered here, namely:

wherein: q (t) dynamic flight pressure during ascent, q_maxThe maximum dynamic pressure allowed during the ascent of the aircraft.

For a given aircraft, the fuel economy of the ascent process is most equivalent to the maximum remaining mass when the aircraft reaches the target trajectory. Therefore, the objective function of the aerospace vehicle ascent trajectory optimization problem can be written as:

min J＝-m(t_f) (8)

solving the ascending track optimization problem of the single-stage orbit-entering aerospace craft described by the equations (4) - (8) can obtain the maximum orbit-entering quality of the single-stage orbit-entering aerospace craft launched by the plateau boosting.

By adopting the similar method, the ascending tracks of other single-stage orbit-entering aerospace flying schemes without adopting plateau boosting launching are optimized to obtain corresponding orbit-entering quality, and the corresponding orbit-entering quality is compared with the orbit-entering quality of the single-stage orbit-entering aerospace vehicle adopting plateau boosting launching, so that the advantages of the plateau boosting launching can be quantitatively analyzed.

As mentioned above, the altitude h of the altitude is taken_P5000 m; latitude phi of transmitting point ₀30 °; the initial total mass of the single-stage in-orbit aircraft is m₀200000 kg; the aircraft is accelerated to v from the boosting launching platform_Boost,maxTaking off at 659.21m/s, and accelerating the rail by using RBCC combined power (the RBCC combined power adopts hydrogen fuel); the target track is a circular track with a height of 200 km. Solving the trajectory optimization problem described by equations (4) - (8) can result in an energy-optimal trajectory and maximum on-track quality. The altitude time curve of the burn-up optimum rise trajectory is shown in fig. 4, the speed time curve is shown in fig. 5, and the aircraft mass versus time curve is shown in fig. 6. It can be seen that the maximum rail inlet mass of the single-stage rail inlet aircraft in the scheme of the invention is 61360.84kg, and the percentage of the rail inlet mass in the initial total mass of the aircraft is 30.68%. If plateau boosting launching is not adopted, the aircraft at sea level takes off from static acceleration by means of own RBCC power until the aircraft enters the orbit, the maximum mass of the entering the orbit is 52767.25kg, and the mass of the entering the orbit accounts for 26.38 percent of the initial total mass of the aircraft. If boost launching is adopted on land at sea level height, under the same dynamic pressure constraint (q)_max160kPa), a single stage in-orbit aircraft can only be accelerated to v_Boost,max511.10m/s, the inlet rail mass of the aircraft was 58725.14kg, which accounted for 29.36% of the initial total mass of the aircraft. Table 2 shows the performance comparison of the inventive scheme with a single-stage rail-in scheme for other transmission modes. Since the carrying ratio of most air-to-air carrying systems is between 1.5 and 2.5%, even 1% improvement is very considerable.

The embodiment shows that the plateau boosting launching aerospace flying scheme provided by the invention can obviously improve the rail-entering quality of a single-stage rail-entering aircraft. The improvement of the quality of the rail entering means that more quality can be distributed to the subsystems of the aircraft load, the structure of the aircraft, the engine, the thermal protection system and the like, so that the carrying capacity of the single-stage rail entering aircraft can be improved, and the design difficulty of the subsystems of the single-stage rail entering aircraft can be reduced.

TABLE 2 in-orbit performance of plateau boost launch and its comparison with other launch modes

The above embodiments are only for illustrating the technical idea of the present invention, and the protection scope of the present invention is not limited thereby, and any modifications made on the basis of the technical scheme according to the technical idea of the present invention fall within the protection scope of the present invention.