User:Chessrat/Interplanetary Transport System (2016 proposal)
.jpg){kind=spacer} Rendering of an Interplanetary Transport System launch vehicle landing on the launch pad | |
| Function | Mars colonization |
|---|---|
| Manufacturer | SpaceX |
| Country of origin | United States |
| Project cost | US$10 billion (before generation of positive cash flow, 2016 estimate)[1][2] |
| Cost per launch | US$62 million (2016 estimate) |
| Size | |
| Height | 122 m (400 ft) |
| Diameter | 12 m (39 ft) booster rocket |
| Width | 17 m (56 ft) spaceship or tanker |
| Mass | 10,500 t (23,100,000 lb)[3] |
| Stages | 2 |
| Capacity | |
| Payload to LEO | |
| Mass | 300 t (660,000 lb) reusable 550 t (1,210,000 lb) expendable[3] |
| Payload to Mars | |
| Mass | 450 t (990,000 lb)[3] with propellant refill in Earth orbit |
| Launch history | |
| Status | Cancelled |
| Launch sites |
|
| First stage – ITS Booster | |
| Height | 77.5 m (254 ft) |
| Diameter | 12 m (39 ft) |
| Empty mass | 275 t (606,000 lb)[3] |
| Gross mass | 6,975 t (15,377,000 lb)[3] |
| Powered by | 42 Raptor (sea level) |
| Maximum thrust | 128 MN (29×106 lbf) sea level 138 MN (31×106 lbf) vacuum[3] |
| Specific impulse | 334 s (3.28 km/s) sea level [3] |
| Propellant | Subcooled CH4 / LOX |
| Second stage – Interplanetary Spaceship | |
| Height | 49.5 m (162 ft) |
| Width | 17 m (56 ft) |
| Empty mass | 150 t (330,000 lb)[3] |
| Gross mass | 2,100 t (4,600,000 lb)[3] |
| Powered by | 9 Raptor (6 vacuum, 3 sea level)[3] |
| Maximum thrust | 31 MN (7.0×106 lbf) vacuum[3] |
| Specific impulse | 382 s (3.75 km/s) vacuum, for 6 engines 361 s (3.54 km/s) vacuum, for 3 engines[3] |
| Propellant | Subcooled CH4 / LOX |
| Second stage – ITS Tanker | |
| Height | 49.5 m (162 ft) |
| Width | 17 m (56 ft) |
| Empty mass | 90 t (200,000 lb)[3] |
| Gross mass | 2,590 t (5,710,000 lb)[3] |
| Powered by | 9 Raptor (6 vacuum, 3 sea level) |
| Maximum thrust | 31 MN (7.0×106 lbf) vacuum |
| Specific impulse | 382 s (3.75 km/s) vacuum, for 6 engines 361 s (3.54 km/s) vacuum, for 3 engines[3] |
| Propellant | Subcooled CH4 / LOX |
.jpg){kind=spacer}
The Interplanetary Transport System was a 2016 design for a privately-funded orbital launch vehicle and spaceship to be developed by SpaceX. The initial design objective of the vehicle was to launch a variety of SpaceX Interplanetary Transport System missions to Mars and other destinations in the beyond-Earth-orbit portion of the Solar System. Design work on the vehicle began in 2012 and first launch was not expected before the 2020s.[1] In the event, the vehicle was not developed as planned in 2016.[4]
The ITS launch vehicle was to be operated as a somewhat unusual two-stage rocket. Its first stage was to have been powered by 42 Raptor rocket engines—designed and manufactured by SpaceX—operating on densified methane/oxygen, propellants that have not been widely used as rocket propellants in the past. Like the Falcon 9 orbital launch vehicle that preceded it, the ITS launch vehicle's first stage design was intended to be reusable, following a return to the launch site and vertical landing following each launch. When announced, is was also designed to have a new feature for SpaceX launch vehicles: full reusability of even the second-stage and orbital spacecraft as well. The large payload capacity of the launch vehicle placed it into the super-heavy lift class, with the ability to place 300 tonnes (660,000 lb) into low Earth orbit in reusable configuration and 550 tonnes (1,210,000 lb) in expendable mode.[3]
The second stage of the Earth launch vehicle was to have been one of two spacecraft that would be used on the launch vehicle. Both spacecraft, unusually, would also serve as upper stages during the launch. Both were to be powered by six vacuum-optimized Raptor rocket engines with three additional sea-level-nozzle Raptor engines for maneuvering. Thus, the element of the launch vehicle that provides second-stage acceleration to orbital velocity on all launches from Earth would also be used—in much longer-duration roles—as on-orbit spacecraft. The two model options were the ITS tanker, a transport carrier of propellant cargo to Earth orbit; and the Interplanetary spaceship, a very long-duration carrier of both passengers and space cargo to interplanetary destinations, and which would also serve as both a descent and ascent vehicle at Mars.
The high-level specifications for the vehicle were publicly announced in September 2016, but by July 2017, SpaceX had stated they would not build the super-heavy vehicles as previously planned, but would instead build a "still large" but much smaller launch vehicle first - that would be revealed as the BFR.[4][5]
Description and technical specifications
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The ITS launch vehicle stack was to be composed of two stages. The first stage would always have been an interplanetary booster while the second stage may have been either an interplanetary spaceship (for beyond-Earth-orbit missions) or an ITS tanker (for on-orbit propellant transfer operations).
Both stages of the ITS launch vehicle would have been powered by Raptor bipropellant liquid rocket engines utilizing the full flow staged combustion cycle with liquid methane fuel and liquid oxygen oxidizer.[6] Both propellants would have been fully in the gas phase before entering the Raptor combustion chamber.[7] Both stages would have utilized a bleed-off of the high-pressure gas for autogenous pressurization of the propellant tanks, eliminating the problematic high-pressure helium pressurization system used in the Falcon 9 launch vehicle.[8][9] The self-pressurization gas system is a critical part of SpaceX strategy to reduce launch vehicle fluids from five in their legacy Falcon 9 vehicle family to just two, eliminating not only the helium tank pressurant but all hypergolic propellants as well as nitrogen for cold-gas reaction-control thrusters.[10]
The overall launch vehicle height, first stage and the integrated second-stage/spacecraft, will be 122 m (400 ft).[11] Both stages of the ITS LV will be constructed of lightweight-yet-strong carbon fiber, even the deep-cryogenic propellant tanks, a major change from the aluminum-lithium alloy tank and structure material used in SpaceX Falcon 9 family of launch vehicles. Both stages are fully reusable and will land vertically, technology initially developed on the Falcon 9 launch vehicle first stages in 2012–2016.[8][9] Gross liftoff mass is 10,500 tonnes (23,100,000 lb) at a lift-off thrust of 128 meganewtons (29,000,000 lbf). ITS LV would be able to carry a payload to low-Earth orbit of 550 tonnes (1,210,000 lb) in expendable-mode and 300 tonnes (660,000 lb) in reusable mode.[3]
.jpg){kind=spacer}
ITS booster
[edit]The first-stage ITS booster, or Interplanetary booster—is a 12 m (39 ft)-diameter, 77.5 m (254 ft)-high, reusable rocket powered by 42 sea-level rated Raptor engines producing over 3,024 kilonewtons (680,000 lbf) of thrust in each engine. Total booster thrust is approximately 130 MN (29,000,000 lbf), several times the 36 MN (8,000,000 lbf) thrust of the Saturn V Moon mission launch vehicle.[8]
The engine configuration will include 21 engines in the outer ring and 14 in the inner ring, with these 35 engines fixed in place. The center cluster of seven engines are gimbaled for directional control, although some directional control to the rocket is also available by utilizing differential thrust on the fixed engines. Design thrust on each engine is variable between 20 and 100 percent of rated thrust.[9]
Methane/oxygen will also be used to power the control thrusters, as gas thrusters rather than the subcooled liquid used to power the main engines. The methalox control thrusters will be used to control booster orientation in space, as well as to help provide additional accuracy in landing once the velocity of the descending booster has slowed.[9]
The design is intended to use about seven percent of the total propellant load at launch in order to support the reusable aspect and bring the booster back to the launch pad for a vertical landing, assessment, and relaunch,[9] assuming a separation velocity of approximately 8,650 km/h (2.40 km/s).[12] During atmospheric reentry, once the atmosphere is sufficiently dense, grid fins will be used to control the attitude of the rocket and fine tune the landing location.[9] The booster return flights are expected to encounter loads that are lower than those experienced on the Falcon 9 rentries, principally because it will have both a lower mass ratio and a lower density than Falcon 9.[13] The booster will be designed for 20 G nominal loads, and possibly as high as 30–40 G's without breaking up.[13]
In contrast to the landing approach used on SpaceX mid-2010s reusable rocket first stages—either a large, flat concrete pad or downrange floating landing platform used with Falcon 9—the ITS booster will be designed to land on the launch mount itself, where it may then be refilled with propellant and checked out for follow-on flights.[9]
Spacecraft that operate briefly as upper stages during launch
[edit]The ITS launch vehicle does not have a dedicated and single-function second stage in the way most launch vehicles have had. Instead, the upper stage function of gaining sufficient velocity to place a payload into Earth orbit is provided as a relatively short term role by a spacecraft that has all the requisite systems for long-duration spaceflight.[9] This is not a role that most upper stages have had in launch vehicle designs through the 2010s, as typical upper stage on-orbit life is measured in hours. Previous exceptions to this norm exist, for example the Space Shuttle orbiter provided part of the boost energy and all of the second stage energy for lofting itself into low-Earth orbit. Differences also exist: the Space Shuttle expended its propellant tank and primary launch vehicle structure on ascent, whereas the ITS first- and second-stage options are designed to be fully reusable.
In the 2016 design, SpaceX had identified two spacecraft that would also play the upper stage role on each Earth-away launch: the interplanetary spaceship and the ITS tanker. Both spacecraft are the same physical external dimensions: 49.5 m (162 ft)-long and 12 m (39 ft)-diameter (17 m (56 ft) across at the widest point. Both designs were powered by six vacuum-optimized Raptor engines, each producing 3.5 MN (790,000 lbf) thrust, and were to have had three lower-expansion-ratio Raptor engines for in-space maneuvering as well as during descent and landing to allow for reuse on future launches.[8][3]
Interplanetary spaceship
[edit]The Interplanetary spaceship was a large passenger-carrying spacecraft design proposed by SpaceX as part of their ITS launch vehicle in September 2016. The ship would operate as a second-stage of the orbital launch vehicle on Earth-ascents—and would also be the interplanetary transport vehicle for both cargo and passengers— capable of transporting up to 450 tonnes (990,000 lb) of cargo per trip to Mars following propellant-refill in Earth orbit.[8]
.jpg)
In addition to use during maneuvering, descent and landing, the three lower-expansion-ratio Raptor engines were also to have been used for initial ascent from the surface of Mars.[8] In 2016, the first test launch of a spaceship was not expected until 2020 or later, and the first flight of the ITS booster was expected to follow a year or more later.[1]
.jpg)
Early Mars flights—in the mid-2020s or later—were expected to carry mostly equipment and few people.[14]
ITS tanker
[edit]The ITS tanker is a propellant tanker variant of the ITS second stage spacecraft. This spacecraft design was to be used exclusively for launch and short-term holding of propellants to be transported to low-Earth orbit. Once on orbit, a rendezvous operation was to have been effected with one of the interplanetary spaceships, plumbing connections made, while a maximum of 380 tonnes (840,000 lb) of liquid methane and liquid oxygen propellants would be transferred in one load to the spaceship. To fully fuel an interplanetary spaceship for a long-duration interplanetary flight, it was expected that up to five tankers would be required to launch from Earth, carrying and transferring a total of nearly 1,900 tonnes (4,200,000 lb) of propellant to fully load the spaceship for the journey.[3][9]
Following completion of the on-orbit propellant offloading, the reusable tanker was to reenter the Earth's atmosphere, land, and be prepared for another tanker flight.[3]
Reusability
[edit]Both stages were designed by SpaceX to be fully reusable and were to land vertically, using a set of technologies previously developed by SpaceX and tested in 2013–2016 on a variety of Falcon 9 test vehicles as well as actual Falcon 9 launch vehicles.[8]
Importantly, the "fully and rapidly reusable" aspect of the ITS launch vehicle and spacecraft design was the largest factor in the SpaceX analysis for bringing down the currently huge cost of transporting mass to space, in general, and to interplanetary destinations, in particular. While the transport system under development in 2016-2017 relied on a combination of several elements to make long-duration beyond Earth orbit (BEO) spaceflights possible by reducing the cost per ton delivered to Mars, the reusability aspect of the launch and spacecraft vehicles alone was expected by SpaceX to reduce that cost by approximately 2 1/2 orders of magnitude over what NASA had previously achieved on similar missions. Musk stated that this is over half of the total 4 1/2 orders of magnitude reduction that he believes is needed to enable a sustainable settlement off Earth to emerge.[15][3]
Launch location
[edit]As of September 2016, the planned location for initial launches of the ITS launch vehicle was LC-39A, at SpaceX's leased pad at Launch pad 39A on the Florida coast, the same launchpad where Apollo 11 launched in 1969 to the Moon and from where subsequent Apollo Missions were also launched.[8]
Operations concept
[edit]![[icon]](/wiki/File:Wiki_letter_w_cropped.svg){kind=small} | This section needs expansion with: needs info on Mars entry/descent. You can help by adding to it. (September 2016) |
The concept of operations for ITS launches envisions the fully loaded second-stage reaching orbit with only minimal propellant remaining in the interplanetary spaceship vehicle's tanks. At this time, while the spaceship remains in Earth orbit, three to five cargo second stages—called ITS tankers—would be launched from Earth carrying additional methane fuel and liquid oxygen oxidizer to rendezvous with, and transfer propellant to, the outgoing spaceship. Once refueled, the spaceship would perform a trans-Mars injection burn, departing Earth orbit for the interplanetary portion of the journey.[8]
Outer planet concepts
[edit]
The overview presentation on the Interplanetary Transport System architecture given by Musk in September 2016 included concept slides outlining missions to the Saturnian moon Enceladus, the Jovian moon Europa, Kuiper belt objects, a fuel depot on Pluto and even the uses to take payloads to the Oort Cloud.[8] "Musk said ... the system can open up the entire Solar System to people. If fuel depots based on this design were put on asteroids or other areas around the Solar System, people could go anywhere they wanted just by planet or moon hopping. 'The goal of SpaceX is to build the transport system ... Once that transport system is built, then there is a tremendous opportunity for anyone that wants to go to Mars to create something new or build a new planet.'"[9] Outer planet trips would likely require propellant refills at Mars, and perhaps other locations in the outer Solar System.[16] This emphasis was totally missing in the update one year later when the smaller BFR launch vehicle and spacecraft were introduced.
Economic considerations
[edit]Funding
[edit]The development and manufacture of the new two-stage launch vehicle has been to date (through 2016), and is being, privately funded by SpaceX. The entire project is even possible only as a result of SpaceX multi-faceted approach focusing on the reduction of launch costs.[8]
The full build-out of the Mars colonialization plans will likely be funded by both private and public funds, according to Musk in September 2016. The speed of commercially available Mars transport for both cargo and humans will be driven, in large part, by market demand as well as constrained by the technology development and development funding.
Elon Musk has said that there is no expectation of receiving NASA contracts for any of the ITS system work. He also indicated that such contracts, if received, would be good.[17]
Competition for the American super-heavy-lift market
[edit]In August 2014, media sources noted that the US launch market may have two competitive launch vehicles available in the 2020s to launch payloads of 100 tonnes (220,000 lb) or more to low Earth orbit. The US government is currently developing the Space Launch System (SLS), a super heavy-lift launch vehicle designed to propel very large payloads of 70 to 130 tonnes (150,000 to 290,000 lb) to low Earth orbit.[18][19]
Blue Origin's New Glenn rocket, announced in September 2016, is also expected to compete in the super-heavy lift class.[20] In March 2017, New Glenn's reusable payload capacity was announced as 45 tonnes to LEO and 13 tonnes to GTO.[21]
See also
[edit]References
[edit]- ^ a b c
Foust, Jeff (27 September 2016). "SpaceX's Mars plans call for massive 42-engine reusable rocket". SpaceNews. Retrieved 14 October 2016.
Musk stated it's possible that the first spaceship would be ready for tests in four years, with the booster ready a few years after that, but he shied away from exact schedules in his presentation. 'We're kind of being intentionally fuzzy about the timeline,' he said. 'We're going to try and make as much progress as we can with a very constrained budget.'
- ^
Elon Musk (27 September 2016). Making Humans a Multiplanetary Species (video). IAC67, Guadalajara, Mexico: SpaceX. Retrieved 3 October 2016.
{{cite AV media}}: CS1 maint: location (link) - ^ a b c d e f g h i j k l m n o p q r s t u "Making Humans a Multiplanetary Species" (PDF). SpaceX. 27 September 2016. Archived from the original (PDF) on 28 September 2016. Retrieved 29 September 2016.
- ^ a b Cite error: The named reference
issR&Dconf20170719-49:48was invoked but never defined (see the help page). - ^ https://www.theverge.com/2017/9/26/16360348/spacex-elon-musk-iac-mars-colonization-interplanetary-transport-system
- ^ Bergin, Chris (11 May 2015). "Falcon Heavy enabler for Dragon solar system explorer". NASASpaceFlight.com. Retrieved 12 May 2015.
- ^ Cite error: The named reference
nsf20140307was invoked but never defined (see the help page). - ^ a b c d e f g h i j k Bergin, Chris (27 September 2016). "SpaceX reveals ITS Mars game changer via colonization plan". NASASpaceFlight.com. Retrieved 27 September 2016.
- ^ a b c d e f g h i j Richardson, Derek (27 September 2016). "Elon Musk Shows Off Interplanetary Transport System". Spaceflight Insider. Retrieved 3 October 2016.
- ^ Cite error: The named reference
nsf20161003was invoked but never defined (see the help page). - ^ https://twitter.com/elonmusk/status/780831628104966144
- ^ Berger, Eric (28 September 2016). "Musk's Mars moment: Audacity, madness, brilliance—or maybe all three". Ars Technica. Retrieved 13 October 2016.
- ^ a b Cite error: The named reference
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Elon Musk (27 September 2016). Making Humans a Multiplanetary Species (video). IAC67, Guadalajara, Mexico: SpaceX. Event occurs at 9:20–10:10. Retrieved 10 October 2016.
So it is a bit tricky. Because we have to figure out how to improve the cost of the trips to Mars by five million percent ... translates to an improvement of approximately 4 1/2 orders of magnitude. These are the key elements that are needed in order to achieve a 4 1/2 order of magnitude improvement. Most of the improvement would come from full reusability—somewhere between 2 and 2 1/2 orders of magnitude—and then the other 2 orders of magnitude would come from refilling in orbit, propellant production on Mars, and choosing the right propellant.
{{cite AV media}}: CS1 maint: location (link) - ^ Cite error: The named reference
gw20160927was invoked but never defined (see the help page). - ^ https://twitter.com/SpcPlcyOnline/status/780894498893225984
- ^ Cite error: The named reference
nsf20140830was invoked but never defined (see the help page). - ^
"KSC meeting portrays SLS as scrambling for a manifest plan". 12 January 2016. Retrieved 14 January 2016.
Also notable – though understandably not referenced at the KSC meeting – is SpaceX's plan to have its BFR – a reusable booster with the power of two Saturn Vs – already up and running by the 2020s, ahead of MCT (Mars Colonial Transporter) missions.
- ^ Leahy, Bart (12 September 2016). "Blue Origin reveals New Glenn launch vehicle plans". Spaceflight Insider. Retrieved 9 October 2016.
- ^ Foust, Jeff (7 March 2017). "Eutelsat first customer for Blue Origin's New Glenn". Space News.
External links
[edit]- SpaceX Interplanetary Transport System, video released by SpaceX, 27 September 2016.
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