Difference between revisions of "Orbital Launch Vehicles Roadmap"

From MIT Technology Roadmapping
Jump to navigation Jump to search
Line 354: Line 354:


=== 2RE Technical model ===
=== 2RE Technical model ===
==== Morphological matrix ====
To explore the trade space for a LEO capable rocket design, the team must consider a variety of design parameters. The two most important figures of merit on which to evaluate a rocket’s capability are cost/launch and payload to orbit (a function of thrust and mass). Not surprisingly, the cost/launch is dominated by the re-usability of a design. This is why our company is focusing so heavily on this aspect of the design vector (see tornado diagram below).
To explore the trade space for a LEO capable rocket design, the team must consider a variety of design parameters. The two most important figures of merit on which to evaluate a rocket’s capability are cost/launch and payload to orbit (a function of thrust and mass). Not surprisingly, the cost/launch is dominated by the re-usability of a design. This is why our company is focusing so heavily on this aspect of the design vector (see tornado diagram below).
<br>
<br>
[[File:Launch System MM.png|700px|Launch System Morphological Matrix]]
[[File:Launch System MM.png|700px|Launch System Morphological Matrix]]
<br>
<br>
==== Sensibility analysis ====
Based on the design decisions shown above one can see the variety of designs for achieving LEO. For example, notice that the Soyuz, RD-180 design employs 20 engines to lift a payload of 7 metric tonnes, while the RS-25 driven Space Shuttle uses just 3 engines to lift a payload of 25 tonnes.
Based on the design decisions shown above one can see the variety of designs for achieving LEO. For example, notice that the Soyuz, RD-180 design employs 20 engines to lift a payload of 7 metric tonnes, while the RS-25 driven Space Shuttle uses just 3 engines to lift a payload of 25 tonnes.



Revision as of 04:04, 3 December 2019

Roadmap Overview

Orbital launch vehicles (LV) are internally propelled vehicles used to carry payloads from Earth’s surface to Earth orbit or beyond. The payloads vary from case to case but they can be satellites, spacecraft or interplanetary probes. They are powered by rocket engines that generate large amounts of thrust even in vacuum by means of expelling hot gas through a nozzle. The primary function of rocket engines is to convert chemical energy to kinetic energy. There are several different styles of rocket engines that are used today (all of which meet the primary functional requirements) but the perform those functions in slightly different ways with slightly different architectures. These architectures are all determined by their fuel type and their fuel consumption method. The rocket engines we will examine here include solid rockets, open-cycle liquid fuel, closed-cycle full flow liquid fuel, and nuclear.

As an example, an Ariane 5 LV is typically used to insert up to 2 geostationary satellites into a GTO per launch. Its launch mass is about 777 metric tons and has a LEO capacity of about 20 tons and a GTO capacity of about 10 tons.

Ariane 5 Schematic

On a typical flight, the different stages of the OLV such as the first stage, the solid rocket boosters, and interstage will be jettisoned to reduce the mass of the vehicle until the payloads are precisely deployed at the desired orbit.

Ariane 5 typical flight profile

This roadmap is a Level-1 point of view of the launch vehicles as a technology that enables the Human race to transport cargo from the surface of the Earth to outer space as well as a Level-2 roadmap of liquid-fuel rocket engines which are one of the most used technologies of rocket engines. The corresponding ids for both roadmaps are 1LV and 2RE.

DSM Allocation

1LV DSM Allocation

The following DSM shows the relationship of the Launch Vehicles roadmap to other high or lower level roadmaps. The Green cells represent the location of this roadmap and the Blue cells represent the location of the 2RE roadmap detailed below. The letters R and D are for required and dependency respectively.

1LV DSM.png

The following tree structure can be also extracted from it:

  • 1LV Launch vehicles
    • 2RE Rocket engines
      • 3PROP Propellants
      • 3NOZ Nozzles
      • 3CC Combustion chambers
      • 3PUMPS Pumps
      • 3TVC Thrust vectoring
    • 2GNC Guidance, Navigation and control
      • 3ATTI Attitude determination
      • 3CONT Attitude control
      • 3GUID Guidance
    • 2STRUCT Structures
    • 2COMMS Telecommunications
  • 1GS Ground Stations

2RE DSM Allocation

Below is a schematic DSM for the simplified and generalized liquid-fuel rocket engine described in the first section. Cells colored black indicate a physical connection between formal elements. Red indicates a mass flow between formal elements. Green illustrates an energy flow between formal elements. There can be multiple colors for a single cell.
Liquid Rocket Engine DSM.png

Dependency tree for 2RE missing here
Feedback was: roadmap does not include a dependency tree - where does the technology fit in relative to others at different levels?

Roadmap model using OPM

The following Object Process Diagram describes the Orbital Launch Vehicle technology point of view for this roadmap. The main object of the diagram is the different launch vehicles, its decomposition into main components/subsystems like propulsion system, structures, tanks, avionics, payload adapters, and the main attributes. Finally, the processes in the lifecycle are described as the integration of the payloads and the actual launch.

Orbital launch vehicles OPD

The attributes exhibited by the LV object such as Payload mass capacity, payload volume capacity, reliability, cost/kg, Launch frequency, Reusability and Stage count that are the main FOMs of a Launch Vehicle.

OPM missing here for 2RE.
Feedback was: you made a number of OPMs for varying technologies of rocket engines. I’d suggest either selecting only one, or creating a more generic OPM that could be applied to any type. ○ Indicate the FOMs on the OPM and their associated units.
The OPM shown is very high level and shows more the launch vehicle operations and recovery. Should there be a second OPM model at level 2 showing the details of the inside operations within a (liquid fueled) rocket engine?

Figures of merit

1LV FOMs

The table below shows a list of FOMs by which Orbital Launch Vehicles can be assessed.

Figure of Merit Units Description
Payload to LEO [Kg/Year] Payload mass that can be put into a 500 Km circular low earth orbit for a specific launch vehicle every year. This takes into account the production rate of the rockets and, if applicable, the reusability.
Payload to mass Ratio [Kg/Kg] Mass capacity to LEO over total LVs mass (including the payload).
Reliability [non-dimensional] Successful launches over total launches.

Cost per Kg as a FOM wasn't considered in this roadmap because of the difficulty of obtaining accurate data.

Physical principles

In order to put a payload in orbit, an OLV needs to accelerate to a certain velocity in a certain direction at a specific altitude from the center of the Earth. This requirement can be derived from Newton’s Universal Gravitational Law and can be approximated for circular orbits as:

Where G is the universal gravitational constant, M the mass of the Earth and r the distance to the center of the planet of the orbit. So for example, a 500km circular orbit around the Earth will require a velocity of approximately 7.61 km/s or 27405 Km/h. A few more km/s are usually needed to account for atmospheric losses and other non-idealities.

In other to achieve that velocity, OLV uses rockets engines that use a combination of fuel and oxidizers (known as propellants) to create a high-pressure gas that is then accelerated by a converging-diverging nozzle to create thrust.

<math>\Delta v = v_\text{e} \ln \frac{m_0}{m_f} = I_\text{sp} g_0 \ln \frac{m_0}{m_f}</math>

Where ΔV is the change of velocity of the vehicle, m0 is the initial total mass, including propellant, also known as wet mass, mf is the final total mass without propellant, also known as dry mass, ve is the exhaust velocity and is equal to Isp times g0. Here, Isp is the specific impulse in the dimension of time and is a measure of effectively the rocket use the propellant and g0is standard gravity. In other words, this equation relates the total amount of velocity change that a rocket engine can create on a system by means of the initial and final mass (loss of mass of propellant), the efficiency. When multiple stages are present this equation must be considered for each stage.

So, as ΔV is known, then choosing a propulsion system will define the Isp and this will lead to the ratio of the initial and final mass necessary or which is equivalent to the amount of mass for structure tanks and engines, payload and propellant that is needed.

For example, this table shows some figures of merit of different rocket engines.

OLV Propellant % of total mass Payload % of total mass
Saturn V 85 4
Space Shuttle 85 1
Soyuz 91 2

In conclusion, the only FOM that is directly related to a physical principle is the Payload to mass Ratio described above.

Payload to mass Ratio [Kg/Kg]

Useful payload to orbit is driven by the Rocket Equation and then affected by the different efficiency factors and non-idealities of the real Launch Vehicles designed and implementation. The trend in the payload to mass ratio is illustrated in the following plot using historical database <ref>McDowell's JSR Database (Links not working)</ref> since 1957. Only those LVs which has successfully achieved orbit at least once and carrying more than 10 Kg of payload were considered. A trend towards bigger LVs and more efficient can be observed.

Mass vs Payload plot

Caveat: the LEO capacity figure is an approximation and is not normalized to a specific orbit across LVs. A substantial difference might be present if the stated LEO capacity was calculated for a 600 KM SSO orbit instead of a 400 Km equatorial orbit.

The evolution over time of this FOM can be seen in the following plot. In this case, only those LV that are better than the previous ones is plotted. LV Performance over time.png

Payload to LEO [Kg/Year]

Payload to LEO can be used to estimate the capacity of the total launchers to put payload in orbit. In this case, two different sub-FOMs where calculated. First, the actual mass launched by aggregating all the masses of all the satellites on every launch per year. This doesn't include the payload adapters and dispensers used for the launch. On the other hand, the potential capacity is the sum of the total LEO capacity for each vehicle aggregated every year. As a reference, the ISS is about 419 tons and the James Webb Space Telescope is approximately 6.2 tons.

Actual and potential mass per year

Reliability

The reliability of LVs has increased significantly during the first 10 years after 1957 reaching levels of above 90% overall. Later years the increment is not that significant and for example, in 2018 the 98.24% of all the launches were successful. This trend and the totals can be seen in the following plot:

Launches and reliability per year

2RE FOM

FOMs missing here.
Feedback was: What are the FOMs vs. the governing equations? It is unclear at the moment. Remember that governing equations are utilized in FOMs for instance if Isp/Weight is an FOM, the equation for Isp is used to determine that FOM.

Alignment with “Company” Strategic Drivers: FOM Targets

ID Strategic driver Alignment with targets
1 To develope a rapidly fully reusable launch system capable of landing payload in the surface of Mars The Starship project currently in the Launch Vehicle roadmap will provide a capacity of 100 tons to LEO in a fully reusable launch vehicle that can be used to land on Mars.
2 To develop a liquid-fueled and reusable rocket engine that can enable an affordable launch marketplace in which we have a distinct first-mover advantage. The liquid fuel rocket engine roadmap will target the development of methane fueled rocket engine that will provide at least 3,000 kN of thrust in vacuum. This would represent a disruptive technology in the rocket engine marketplace.
3 To provide a low-cost solution to satellite launch to LEO with a fast pace (monthly) and an affordable price for small satellites to further fund the other projects of SpaceX SmallSat Rideshare Program will provide small satellite operators with regularly scheduled, dedicated Falcon 9 rideshare missions to sun-synchronous orbit (SSO) for ESPA class payloads' for as low as $1M per mission, which includes up to 200 kg of payload mass.

The company’s technology roadmap is aligned with all three of its strategic drivers. There is sufficient organizational capability, funding, and time to meet our ambitious plan. All of the targets are within the parameters set forth by the governing equations, and thus they are technically feasible.

Positioning of Company vs. Competition: FOM charts

At the highest level, there are two semi-competitive solutions – governmental funded agencies and private companies. Publicly funded agencies are nation specific, and account for between 50% and 75% of all orbital class launches annually. For orbital class launch vehicles, China, India, Iran, and Japan utilize exclusively publicly funded organizations. Russia uses almost exclusively publicly funded organizations with rare exceptions. Chinese and Russian launches together account for ~90% of all publicly orbital class launches in the world on an annual basis. The remaining 50% to 25% of all orbital launches annually are publicly and privately funded but launched by private companies.

Summary Graphs.png

Public Competitive Landscape

China and Russia are the primary consumers of state-funded and state-organized (and state-researched, and state-produced) products. For these examples, the pricing scheme is extraordinarily difficult to find detailed reports. However, one can safely assume that massive amounts of funds are dedicated to the research of new technologies. In examining the development of the “Long March” rocket (the current iteration has roots back to 1993) there have been over 100 launches of various incarnations. Most of which have been almost 100% expendable. There are currently three new Long March rockets in development with differing fuselage diameters to fulfill different mission profiles – including a 100m tall, heavy lift behemoth called the Long March 9. This development of this program must have cost a minimum of tens of billions of dollars.

The Russian space program is another important example to examine. Most of the lift vehicles that the KSRPSC operate are old ICBMs that have been decommissioned. Specifically, there is a major use of R-7 rockets that have provided lifting capability for payloads ranging from sputnik to the Soyuz (after modifications). In fact, the Soyuz-U, a member of the R-7 rocket family, is the single most launched carrier rocket in the world with 786 launches and 22 failures (success rate = 97%). A single launch of a Soyuz-U is claimed to cost ~$50 million bringing the total cost of launching Soyuz-U rockets to ~$40 billion. This excludes development costs, doesn’t account for any other Soyuz launches, and excludes monies paid to the Russian government to use their services. Regardless, it is a reasonable claim to estimate the cost of the R-7 space program to be on the same order of magnitude (tens of billions of dollars, possibly hundreds of billions of dollars) as the Chinese program.

From a competition perspective, the Russian government has been much more willing to work with other governments (including the United States government, the Israeli government, the Ukrainian government, and more). In this sense then, the Russian publicly funded space program is in direct competition with the private sector while simultaneously achieving some levels of internal funding guaranteed and specific research requirements dictated by national defense. The Chinese space program, on the other hand, is not in competition with anyone and in fact is likely not going to be a user of any other space program pending political resolutions.


Private Competitive Landscape

Within the private sector there was a duopoly that existed prior to 2016 between Arianespace and ULA. Arianespace is partly owned by 17 separate private entities. Arianespace was initially founded with European governmental agencies but is currently mostly privately held. The largest shareholders of Arianespace are Airbus and Safran SA. Arianespace was founded with the specific intent of enabling commercial launches to space. From 2007 to 2015, Arianespace accounted for between 20% and 30% of the private space market for orbital launch vehicles. ULA is a joint venture that has existed between Boeing and Lockheed Martin since 2006. The venture was chiefly formed to help the US government launch their own military and civilian satellites, but ULA also allows for commercial launches.

Launch Costs Summary Table.png

Prior to 2016, Northrop Grumman, Arianespace, and ULA all occupied slightly different markets as launch providers. Northrop Grumman was largely a small payload and cheap launch provider. If you needed an orbital class rocket, and a small-lift vehicle didn’t have the diameter to hold your satellite, Northrup dominated because of their cheap launches. If you had a light, but large payload, then Ariane dominated with a massive 5.2m hull and a cost that was comparable to much smaller diameter rockets. If your payload mass exceeded 16,000kg, then ULA was your only option with their Atlas and their massive Delta rocket offerings. Given that each provider was well positioned in this landscape, they were all in the position of defenders with the emergence of SpaceX’s Falcon 9 rocket.

Everything changed in 2016. SpaceX now dominates the private sector launch market – and in fact, in 2018 China launched the most orbital class rockets (38) and the second most rockets were launched by SpaceX (21) with Russia launching 20, and ULA launching 8. In 2018, SpaceX alone accounted for 57% of all the launches in the private sector. In a span of one year, SpaceX upset the duopoly held by Arianespace and ULA and became the largest single force in the private launch provider sector. See the graphs and tables below to summarize the private launch capabilities that currently exist.

2018 launches per lv.png

By 2016, the Falcon 9 had flows 20 times with one failure. With a cost of $50 million the Falcon 9 and SpaceX were unquestionably in the position of attacker and pioneer. The Falcon 9 could outperform every other vehicle in almost every realistic launch scenario. There were a few circumstances where a payload was too heavy or too wide to work with the Falcon 9, and in those situations either Ariane or Delta was used. It is no surprise however, that clients flocked to the affordable solution provided by SpaceX. In almost every scenario, the Falcon 9 is a dominating strategy.

SpaceX continues this strategy of attack and pioneering by developing the Starship platform. No firm claim for launch costs have been settled on for Starship, but it will have payload capacity of ~100,000 kg and a diameter of 9m dwarfing every other private provider option. Estimates for cost range from gobsmackingly low ($10 million – Elon Musk at the IAC 2017) to shockingly low ($100 million – Business Insider estimate). If the real cost per launch is in that window, then Starship paired with Falcon 9 will become dominant designs.
Payload to LEO Tradespace.pngHull Diameter Tradespace.png

Feedback:
● Where is the pareto front and utopia point on the plots shown (max payload to LEO vs. launch cost and hull diameter vs. launch cost)?
● Where would your company’s technology be on these charts?

Technical Model: Morphological Matrix and Tradespace

1LV Technical model

Orbital requirements

In order to put a payload into a specific orbit, a specific position and velocity vector must be achieved as illustrated in the following diagram:

Orbit.png

This analysis will focus on achieving circular orbits in the Earth orbit. This is not the only possible orbit or trajectory (for example in GTO or interplanetary trajectories), but the results can be extrapolated to those cases if necessary. For a circular orbit, the relationship between the orbit radius and the velocity is:

Equation

<math>v_{orbit} = \sqrt{\frac{\mu}{r_{orbit}}}</math>

Here, μ, is the Earth Gravitational Constant and has a fixed value <math display="inline">3.98574405096E14 \frac{m^3}{s^2} </math> and <math display="inline">r_{orbit}</math> is measured from the center of the Earth. If the altitude of the orbit is needed, the mean radius of the Earth equal to 6371Km must be used. As an example, a typical 500 Km circular orbit around the Earth needs a velocity of 7.61 km/s.

Geometry

Because launch vehicles are (mostly) launched from the surface of the Earth, the geometry of the problem must be considered For a direct launch, this can be seen in the following image:

Launch geometry.png

Using spherical trigonometry (https://www.orbiterwiki.org/wiki/Launch_Azimuth) it can be calculated that:

<math> cos(i) = cos(\Phi)sin(\beta)</math>

Where i is the desired orbital inclination, β is the launch site latitude, and Φ is the launch azimuth. This restricts the orbital inclination to be always greater or equal than the launch site latitude:

<math> i >= \Phi </math>

So for example, if the launch site is located at 30deg latitude, then it won’t be possible to direct launch the payload into an equatorial (0deg) orbit.

Another issue, that helps the launch is Earth’s rotation. Because of it, the launch site will have a tangential velocity that is dependent on the latitude as follows:

<math> v_{earth_{due east}} = \omega_{earth} r_{earth} cos(\Phi) </math>

For example, If launching from the equator where Φ=0 the tangential velocity is maximum (about 463.7 m/s) as opposed to launching from the pole where Φ=90 and there is no tangential velocity at all. All this is only valid if launching due east which is not always the case. If you launch due East from any latitude, then β=90, so the inclination of the resultant orbit ends being the latitude of the launch. To account for this change in final inclination, the previous equation must be modified according to:

<math> v_{earth_{due east}} = \omega_{earth} r_{earth} cos(\Phi) cos(i) </math>

So this potential gain of velocity must be taken into account when calculating the required launch strategy.

Last, if the desired orbit inclination is not achievable by a direct launch, then the launch must perform an inclination change that will require additional velocity (in a specific direction). This can be represented by:

<math> \Delta v_{plane-change}=2V_{orbit}sin(\alpha/2) </math>

Where α is the difference in direct insertion angle to the desired angle.

Losses

During the flight and before achieving the orbital condition, there are losses of energy (or speed) that must be compensated. These losses are:

  • Atmospheric drag which is the resistance of the air of the traveling vehicle
  • Gravity drag which is the cost of having to hold the rocket up in a gravity field.

For a typical launch vehicle, aerodynamic losses are quite small while gravitational losses are bigger. Both depend heavily on the shape of the trajectory used and in the case of the atmospheric drag on the shape of the launch vehicle too. Usually, this will require an additional 15-20% of ΔV to compensate for these losses. 20% will be considered for the analysis.

Rocket equation

In order to achieve a change in velocity, a typical launch vehicle will utilize rocket engines that follow the Tsiolkovsky equation:

<math>\Delta v = v_\text{e} \ln \frac{m_0}{m_f} = I_\text{sp} g_0 \ln \frac{m_0}{m_f}</math>

Where ΔV is the change of velocity of the vehicle, m0 is the initial total mass, including propellant, also known as wet mass, mf is the final total mass without propellant, also known as dry mass, ve is the exhaust velocity and is equal to Isp times g0. Here, Isp is the specific impulse in the dimension of time and is a measure of effectively the rocket use the propellant and g0 is standard gravity. In practical launch vehicles, multiple stages are stacked to create a launch vehicle that discards the unused mass as soon as possible to maximize efficiency. Also, these stages are usually tuned for each part of the flight, for example by having a high thrust to weight ratio on the first stages and a higher Isp on the last stages. For simplicity, that won’t be considered in this model.

Complete model

Considering all the factors together, to get to the desired orbit from a launch site in the earth using a rocket-propelled launch vehicle the following equation can be used:

<math> v_{orbit} + v_{drag} + v_{plane-change} - V_{earth} = I_\text{sp} g_0 \ln \frac{m_0}{m_f} </math>

Which can be rewritten as:

<math> \sqrt{\frac{\mu}{r_{orbit}}}(1 + 2 sin(\alpha/2) + v_{drag} - \omega_{earth} r_{earth} cos(\Phi)cos(i) = I_\text{sp} g_0 ln (\frac{m_0}{mf})</math>

Where:

  • <math> g_0=9.81 \frac{m}{s^2} </math>
  • <math> \omega_{earth} = 7.2921159 E-5 \frac{rad}{second}</math>
  • <math> r_{earth} = 6371 Km</math>

where launch latitude Φ, desired orbit inclination i, plane change requirement α, target orbit radius rorbit, specific impulse Isp the masses m0 and mf are the design variables. Vdrag is left as a design variable too because it can be slightly modified with trajectory optimization and aerodynamics work.

mf represents the final mass of the system which is equal to the launch vehicle mass plus the payload mass, while m0 is the initial mass of the system which is mf plus the propellant mass mp

Morphological matrix

According to the model described above, the morphological matrix from which different launch vehicles configurations can be made is presented:

Attribute / Options 1 2 3 4 5 6
Stage 1 Propellant / Engine None LOX/LH2 KEROLOX Methalox UDMH/N204 Solid
Stage 2 Propellant / Engine None LOX/LH2 KEROLOX Methalox UDMH/N204 Solid
Stage 3 Propellant / Engine None LOX/LH2 KEROLOX Methalox UDMH/N204 Solid
Stage 4 Propellant / Engine None LOX/LH2 KEROLOX Methalox UDMH/N204 Solid
Launch type Surface launch Air launch
Launch site KSC Korou Baikonour Air launch
Reusable Yes No

As an example, a few popular and currently in operations launch vehicles are compared:

Attribute / LV Falcon 9 Soyuz-FG /Fregat Ariane 5 Pegasus XL LongMarch 3B
Stage 1 Propellant / Engine KEROLOX UDMH/N204 LOX/LH2 + Solid Solid UDMH/N204
Stage 1 Propellant / Engine KEROLOX UDMH/N204 UDMH/N204 Solid UDMH/N204
Stage 3 Propellant / Engine None UDMH/N204 None None LOX/LH2
Stage 4 Propellant / Engine None None None None UDMH/N204
Launch type Surface launch Surface launch Surface launch Air launch Surface launch
Launch site KSC Baikonour Korou Air launch XiChang
Reusable Yes No No No No

Sensibility analysis

In this analysis, the sensibility of the design variables for a generic launch vehicle for a particular mission is studied. The mission is the launch of a payload into a Sun-synchronous orbit with the following fixed paramters:

Parameter Value Unit
Orbit altitude 500 Km
Inclination 97 degree
Launch latitude (KSC) 28.57 degree
Isp (LOX/LH2) 440 s
Vdrag 1500 m/s

The main figure of merit under analysis will be the mass ratio r according to:

<math> J(x) = r = \frac{m_f}{m_0} = e^{-\frac{\sqrt{\frac{\mu}{r_{orbit}}}(1 + 2 sin(\alpha/2) + v_{drag} - \omega_{earth} r_{earth} cos(\Phi)cos(i)}{I_{sp}g_0}}</math>

Where the design vector is:

<math> x= [v_{drag}, \Phi, I_{sp}] </math>

So J(x0) = 11%. This means that from the total mass of the rocket, 89% must be propellant and 11% must be structure and payload (which is why it’s probably impossible to achieve yet).

Then, the possible improvements are:

  • Improving the rocket efficiency (Isp)
  • Improving the launch trajectory (Vdrag)
  • Reducing the location of the launch site

Note that because the orbit inclination is 97 it’s actually rotating in the opposite direction of the earth so in this case, the contribution of the Earth tangential velocity must be counteracted and the sign was reversed. Also, the number 426.6 is the product of cos(97) times 463.7 m/s the tangential velocity of the Earth at the Equator.

Calculating the normalized partial derivatives and considering the SSO scenario we get:

<math> \frac{x_{i,0}}{J(X^0)}\frac{\partial r}{\partial I_{sp}}|_{x^0} = 2.20% </math>
<math> \frac{x_{i,0}}{J(X^0)}\frac{\partial r}{\partial V_{drag}}|_{x^0} = -0.34% </math>
<math> \frac{x_{i,0}}{J(X^0)}\frac{\partial r}{\partial \Phi}|_{x^0} = 0.003% </math>

Sensibility.png

This essentially shows that the only effective way of improving the mass ratio is by changing the Isp. If on the other hand, if the payload mass ratio is wanted to be improved, then the structural mass will have a bigger impact in the figure of merit.


2RE Technical model

Morphological matrix

To explore the trade space for a LEO capable rocket design, the team must consider a variety of design parameters. The two most important figures of merit on which to evaluate a rocket’s capability are cost/launch and payload to orbit (a function of thrust and mass). Not surprisingly, the cost/launch is dominated by the re-usability of a design. This is why our company is focusing so heavily on this aspect of the design vector (see tornado diagram below).
Launch System Morphological Matrix

Sensibility analysis

Based on the design decisions shown above one can see the variety of designs for achieving LEO. For example, notice that the Soyuz, RD-180 design employs 20 engines to lift a payload of 7 metric tonnes, while the RS-25 driven Space Shuttle uses just 3 engines to lift a payload of 25 tonnes.

The equation below illustrates how some of these design decisions manifest themselves in the HeilbrunHorton Rocket Cost Equation.
Heilbrun and Horton Rocket Cost Equation
Early analysis of the trade space shows that cost/launch is most sensitive to re-usability and refurbishment cost.
Delta cost launch tornado plot.png

Keys Publications and Patents

Patents

The following patents are those I found interesting from a disruptive point of view. Each of them addresses a different technology that can somehow replace the launch vehicles by performing the same final outcome which is putting payload into orbit but using completely different approaches.

Orbital mechanics of impulsive launch

Inventor: Cartland; Harry E,

Assignee: QUICKLAUNCH, INC.

United States patent 10,427,804

Date: October 1 2019

This patent is about methods to launch into orbit a spacecraft using an impulsive launch. In this case, the spacecraft is initially accelerated in a direction due east from the Earth by a high energy launch system then traveling through the atmosphere until an apogee. The patent claims different methods to further accelerate an impulse launched spacecraft in order to achieve an LEO or a trans planetary trajectory or a way to rendezvous with an orbiting spacecraft.

Space elevator

Inventor: Quine; Brendan Mark,

Assignee: THOTH TECHNOLOGY INC.

United States patent 9,085,897

Date: August 28, 2008

This patent is about an inflatable space elevator tower that can be used to deliver payloads or to install equipment to Earth Orbit. In this case, the core of the tower is constructed by cylindrical inflatable cells with gyroscopic stabilization mechanisms along with it. A pod at the top of the tower allows launching satellites using a kick stage or similar.

The US patent 6,491,258 granted to Lockheed Martin Corporation has a similar concept.

Sea landing of space launch vehicles and associated systems and methods

Inventor: Bezos; Jeffrey P.

Assignee: Blue Origin LLC

United States patent 8,678,321

Date: March 25, 2014

The first claim is a perfect description of what is being patented here: “ A method for operating a space launch vehicle, the method comprising: launching the space launch vehicle from earth in a nose-first orientation, wherein launching the space launch vehicle includes igniting one or more rocket engines on the space launch vehicle; reorienting the space launch vehicle to a tail-first orientation after launch; positioning a landing structure in a body of water; and vertically landing the space launch vehicle on the landing structure in the body of water in the tail-first orientation while providing thrust from at least one of the one or more rocket engines.”

What is very interesting is that this patent was filed by Blue Origin in 2010 and SpaceX sue them. The trial judgment granted spaceX petition and the patent was canceled. This is the resolution of the United States Patent Office. This means that now, anyone is free to attempt to land a rocket on a boat.

Papers and publications

ECONOMIC MODEL OF REUSABLE VS. EXPENDABLE LAUNCH VEHICLES Link

Author: James R. Wertz, Microcosm

Published: IAF Congress, Rio de Janeiro, Brazil Oct. 2–6, 2000

In this paper Wertz analysis the economics of expendable and reusable launch vehicles. He estimates the costs and analysis of what are the volumes at which this technology may create a significant cost reduction in the launch costs. His final conclusion was: “A factor of 5 to 10 near term reduction in launch cost appears feasible. That should increase the size of the market, which can then lead to lower costs in the future.”

Parametric Model of an Aerospike Rocket Engine Link

Author: J. J. Korte NASA Langley Research Center

Published: 38th Aerospace Sciences Meeting & Exhibit 10-13 January 2000 / Reno, NV

In this paper, the author develops a mathematical and executable model of an aerospike engine that can be used in conjunction with other models to simulate launch trajectories utilizing this type of engine. This engine has been under study for decades and the special interests rely on the theoretical high efficiency across different altitudes that can be achieved. No aerospike engine has ever flown to space yet.

Financial Analysis

The corporate objective is to revolutionize space technology with the ultimate goal of enabling people to live on other planets. However, in order to fund the technological revolutions that are required, fundamental fiscal goals must be met. In evaluating the financial viability of the starship there are multiple attributes that must be considered to anchor on a viable price to charge a customer for a single launch. This heavy lifting technology was modelled assuming the enabling technology of functioning raptor engines was in place and functioning to required specs.

Model Assumptions

There are several variables that are pertinent to consider for financial evaluation of this technology program. Each of these variables will impact our main financial drivers. In this evaluation we treat all of these as independent, but it is likely that they will be related to each other. A high-level list of all required includes:

1) The discount rate
2) Vehicle assembly costs (includes engine costs, steel costs, labor, and other parts)
3) Recurring launch costs (includes fuel and refurbishment)
4) Time between launches of a unique starship
5) Number of re-uses that a single unique starship will encounter
6) Financial drivers: NPV and DPI

Please reference the following table for all assumptions that were used for the model:
List of assumptions for rocket financial analysis

Discussion

Four different pricing schemes were considered for evaluation. There are public statements from the company CEO that launches will start charging ~$10M per launch on starship, and then decrease over time to possibly as low as ~$2M per launch for the customer. It is worth noting, that currently the cheapest orbital class rocket to launch is a re-used falcon-9 charging ~$40M per launch to a customer. If these figures are even remotely correct, then cost reductions are on the order of a factor of 4 – 20 over the course of starship operation. Payload to LEO capacity will be increased from ~22 tons to ~100 tons, or a similar increase of a factor of 4 or more. Cost reductions of this magnitude paired with capability increases are heretofore never seen in the private launch sector industry.

The first pricing scheme that was considered is $10M per launch – the high-end public estimate by the company. $5M and $3M provide interesting intermediate points, and $2M represents a low-end estimate of what would be charged to the customer. There is a complex relationship that relates launch cadence and viable re-usability amounts (10, 30, and 100 re-flights were modeled) but the results are unsurprising nonetheless. With increased launch cadence and higher reusability all pricing schemes improve in both NPV and DPI.

The $2M price point has a negative NPV for all examined permutations and even cases with incredibly optimistic cost estimates exceeding our normal assumption envelope. Additionally, in our main modeling cases, the $2M price point never exceeds a DPI of 1.0.
Summary of NPV Scenarios DPI Summary for rocket finances

Recommendation

The $10M price point is the best for all financial measures across all scenarios. However, our recommended course would be to take a baseline pricing approach of ~$5M per launch to remain consistent with the stated corporate goal to enable humans becoming an interplanetary species. Afterall, the lower we can drive prices, the more people will be able to use our services. The $5M price point achieves a DPI of 1.21 in the 30-launch re-use case, and an NPV of $35M. See supporting materials to see the effects of depreciation over time for the different multi-attribute analyses.
Cumulative NPV 4 month launch cadence
Cumulative NPV 3 month launch cadence
Cumulative NPV 1 month launch cadence

List of R&T Projects and Prototypes

Summary

Our technology strategy is to develop an orbital launch vehicle capable of delivering payloads to space at minimal cost. Historically, this has been accomplished by focusing on the payload to LEO and payload to mass ratio figures of merit (how much mass a vehicle can carry and what percentage of the total rocket weight it constitutes). The R&D portfolio presented here aims to further improve these figures of merit, as well as address emerging figures of merit like payload volume to LEO and launch vehicle reusability with the development of the Raptor powered Starship rocket launch vehicle.

Figures of Merit and R&D Objectives

Payload volume to LEO is a figure of merit that measures the payload volume that can be carried to LEO. The Falcon Heavy demonstrated major advancements in the amount of mass a launch vehicle can carry to orbit; however, it does little to address the fact that some payloads are bigger than they are heavy (large optics, habitational modules, space stations, and interplanetary spacecrafts cores).
R&D-1 Starship Fairing Size addresses this by incorporating a larger fairing design in the next generation launch vehicle.
R&D-2– Raptor Engine Design/Configuration aims to increase the payload mass a launch vehicle can carry to LEO by a factor of 6 through more efficient design and higher total engine count.
R&D-3 Modular Raptor Engine will reduce the net cost per launch by reducing refurbishment costs of the Raptor Engine. This will be achieved through a more modular design that is able to take advantage of new facilities that employ assembly line manufacturing techniques.
A summary of the R&D Portfolio is provided below:
Outline of projects for RD for rocket architectures
RD competitive landscape for launch vehicles

Technology Statement

Our target is to develop a new rocket powered launch vehicle capable of delivering 150,000 kg by the year 2030 at a $/kg cost to LEO of under $300. This will be achieved through two R&D projects. The first project (R&D-2– Raptor Engine Design/Configuration) will increase rocket engine efficiency and employ a larger engine configuration on the launch vehicle. The second project, R&D-3 Modular Raptor Engine, will reduce refurbishment cost of the engines by employing a more modular design. Both of these R&D projects will be delivered in phases achieving half of the full-project benefit by 2025 (launch tested), and delivering the remaining value by 2030. Additionally, the company will be funding (R&D-1 Starship Fairing Size) which looks to increase the cargo bay volume on the new launch vehicle by 20% (diameter) by year 2030.