Falcon Heavy

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Falcon Heavy
Falcon Heavy drawing.svg
Drawing of the Falcon Heavy reusable (left) and expendable (right) configurations
Function Orbital launch vehicle and potential Lunar launch vehicle[1]
Manufacturer SpaceX
Country of origin United States
Cost per launch (2014) $77–135M
Size
Height 68.4 m (224 ft)
Diameter 3.66 m (12.0 ft)
Mass 1,462,836 kg (3,225,001 lb)
Stages 2+
Capacity
Payload to LEO 53,000 kg (117,000 lb)
Payload to
GTO
21,200 kg (46,700 lb)
Launch history
Status In Development
Launch sites Vandenberg SLC-4E
KSC LC-39A[2]
Total launches 0
Successes 0
Failures 0
First flight 2015
Boosters (Stage 0)
No. boosters 2
Engines 9 Merlin 1D
Thrust 5,880 kN (1,323,000 lbf) (sea-level)
Total thrust 11,770 kN (2,646,000 lbf) (sea-level)[citation needed]
Specific impulse Sea level: 282 sec[citation needed]
Vacuum: 311 sec[citation needed]
Burn time Unknown
Fuel LOX/RP-1
First stage
Engines 9 Merlin 1D
Thrust 5,880 kN (1,323,000 lbf)(sl)[citation needed]
Specific impulse Sea level: 282 sec[citation needed]
Vacuum: 311 sec[citation needed]
Burn time
Fuel LOX/RP-1
Second stage
Engines 1 Merlin 1D Vacuum
Thrust 801 kN (180,000 lbf)
Specific impulse Vacuum: 342 sec [3]
Burn time 375 seconds[citation needed]
Fuel LOX/RP-1

Falcon Heavy (FH), previously known as the Falcon 9 Heavy, is a spaceflight launch system being designed and manufactured by SpaceX. The Falcon Heavy is a variant of the Falcon 9 – the Falcon Heavy will consist of a standard Falcon 9 rocket core, to which two additional Falcon 9 first stages will be added as strap-on boosters[4] – this will increase the low Earth orbit (LEO) payload to about 53 tonnes, compared to about 13 tonnes for a Falcon 9. The first launch is expected in 2015.[5]

The two-stage-to-orbit vehicle use liquid oxygen (LOX) and rocket-grade kerosene (RP-1) propellants in both stages with the SpaceX-designed Merlin 1D rocket engine. It is planned to have the following payloads:[6][7]

The payload to LEO falls into the "super heavy-lift" range of launch systems under the classification system used by a NASA human spaceflight review panel.[8] SpaceX marketing material frequently claims that the Falcon Heavy is (will be) the most powerful rocket since the Saturn V sent astronauts to the Moon in the early 1970s.[9] However, the Soviet Energia rocket (which successfully launched twice) was in fact more powerful.[10]

History[edit]

SpaceX breaking ground at Vandenberg AFB SLC-4E for the Falcon Heavy launch pad

At an appearance in May 2004 before the U.S. Senate Committee on Commerce, Science and Transportation, Elon Musk testified, "Long term plans call for development of a heavy lift product and even a super-heavy, if there is customer demand. We expect that each size increase would result in a meaningful decrease in cost per pound to orbit. ... Ultimately, I believe $500 per pound or less is very achievable."[11] This $500 per pound goal stated by Musk in 2011 is 35 percent of the cost of the lowest-cost-per-pound LEO-capable launch system in a circa-2000 study, referenced by spaceref.com in 2001, the Zenit, a medium-lift launch vehicle that can carry 14,000 kilograms (30,000 lb) into LEO.[12]

At a press conference at the National Press Club in Washington, DC. on 5 April 2011, Elon Musk stated, “Falcon Heavy will carry more payload to orbit or escape velocity than any vehicle in history, apart from the Saturn V moon rocket, which was decommissioned after the Apollo program. This opens a new world of capability for both government and commercial space missions.”[13]

As of March 2013, Falcon Heavy launch prices are below $1,000 per pound ($2,200/kg) to low-Earth orbit when the launch vehicle is transporting its maximum delivered cargo weight.[14] The published prices for Falcon Heavy launches have moved some from year to year, with announced prices for the various versions of Falcon Heavy priced at US$80-125 million in 2011,[6] US$83-128 million in 2012,[15] and US$77.1-135 million in 2013.[16] Launch contracts typically reflect launch prices at the time the contract is signed.

SpaceX's originally announced schedule expected the Falcon Heavy demonstration rocket would arrive at its west-coast launch location, Vandenberg AFB, California, before the end of 2012,[17] with a launch planned for 2013.[18] After early launches from Vandenberg, the first launch from the Cape Canaveral east coast launch complex was planned for late 2013 or 2014.[13] By late 2012, the company modified the planned first launch date to 2013.[19] Originally, the first launch from the east-coast Cape Canaveral launch complex was planned for 2013, but is currently scheduled for 2015 with the STP-2 US Air Force payload.[20]

The cost of reaching low Earth orbit can be as low as US$1,000/lb, if an annual rate of four launches can be sustained.[17] SpaceX plans to launch 10 Falcon Heavy and 10 Falcon 9 annually.[17] A third launch site, intended exclusively for SpaceX private use, is planned, with locations in Texas, Florida, and Georgia under consideration.[21] A site near Brownsville, Texas is the front runner as of April 2013. SpaceX expects to start construction on the third Falcon Heavy launch facility, after final site selection, no earlier than 2014, with the first launches from the facility no earlier than 2016.[21] In late 2013, SpaceX had projected Falcon Heavy's maiden flight to be sometime in 2014,[7] but as of March 2014 expects the first launch to be in 2015[22] due to limited manufacturing capacity and the need to deliver on the Falcon 9 launch manifest.[5]

While the initial specifications of the new launcher in April 2011 projected LEO payloads of up to 53,000 kilograms (117,000 lb)[6] and GTO payloads up to 12,000 kilograms (26,000 lb),[15] later reports in 2011 projected higher payloads beyond low Earth orbit, including 19,000 kilograms (42,000 lb) to geostationary transfer orbit,[23] 16,000 kilograms (35,000 lb) to translunar trajectory, and 14,000 kilograms (31,000 lb) on a trans-Martian orbit to Mars.[17][24]

By late 2013, SpaceX had raised the projected GTO payload for Falcon Heavy to 21,200 kilograms (46,700 lb).[25]

'Red Dragon' Mars Mission[edit]

As of July 2011, NASA Ames Research Center was developing a concept for a low-cost Mars mission that would use Falcon Heavy as the launch vehicle and trans-Martian injection vehicle, and the Dragon capsule to enter the Martian atmosphere. The concept was conceived to be formally proposed in 2012/2013 as a NASA Discovery mission for launch in 2018 and arrival at Mars several months later; however, as of August 2013, the NASA Discovery Program Office shows no plans for Red Dragon to be funded.[26] The science objectives of the mission would be to look for evidence of life — detecting "molecules that are proof of life, like DNA or perchlorate reductase ... proof of life through biomolecules. ... Red Dragon would drill 3.3 feet (1.0 m) or so underground, in an effort to sample reservoirs of water ice known to lurk under the red dirt." The mission cost is projected to be less than US$425,000,000, not including the launch cost.[27][dated info]

First commercial contract: Intelsat[edit]

In May 2012, SpaceX announced that Intelsat had signed the first commercial contract for a Falcon Heavy flight. It was not confirmed when the first Intelsat launch would occur, but the agreement will have SpaceX delivering satellites to geosynchronous transfer orbit.[28][29]

First DoD contract: USAF[edit]

In December 2012, SpaceX announced its first Falcon Heavy launch contract with the United States Department of Defense (DoD). "The United States Air Force Space and Missile Systems Center awarded SpaceX two Evolved Expendable Launch Vehicle (EELV)-class missions" including the Space Test Program 2 (STP-2) mission for Falcon Heavy, initially scheduled to be launched in 2015.[30][31]

Design[edit]

From left to right, Falcon 1, two versions of Falcon 9 v1.0, three versions of Falcon 9 v1.1, and two versions of Falcon Heavy. (not all versions have flown)

The Falcon Heavy configuration consists of a standard Falcon 9 with two additional Falcon 9 first stages acting as liquid strap-on boosters,[4] which is conceptually similar to EELV Delta IV Heavy launcher and proposals for the Atlas V HLV and Russian Angara. Falcon Heavy will be more capable than any other operational rocket, with a payload to low earth orbit of 53,000 kilograms (117,000 lb).[18] The rocket was designed to meet or exceed all current requirements of human rating. The structural safety margins are 40% above flight loads, higher than the 25% margins of other rockets.[32]

The Falcon Heavy's designed payload capacity, capabilities, and total thrust (17,615 kilonewtons (3,960,000 lbf)) are equivalent to the Saturn C-3 launch vehicle concept (1960) for the Earth Orbit Rendezvous approach to an American lunar landing.[33]

First stage[edit]

The first stage is powered by three Falcon 9 derived cores, each equipped with 9 Merlin 1D engines. The Merlin 1D is an updated version of the previous Merlin engine that provides a sea level thrust of 620 kN (140,000 lbf),[34] and a vacuum thrust of 690 kN (155,000 lbf), and is throttleable from 100% to 70%.[35]

The Falcon Heavy has a total sea-level thrust at liftoff of 17,615 kilonewtons (3,960,000 lbf), from the 27 Merlin 1D engines, while booster thrust rises to 20,017 kilonewtons (4,500,000 lbf) as the booster climbs out of the atmosphere.[7] Falcon Heavy has been designed with a unique propellant crossfeed capability, where some of the center core engines are supplied with fuel and oxidizer from the two side cores, up until the side cores are near empty and ready for the first separation event.[36] Thus, although engines from all three cores ignite at launch, the main core uses little of its own propellant until booster separation.[37] There are three separation events: the simultaneous separation of the two booster cores followed later by the separation of the main booster core from the second stage. This is akin to a three stage rocket and thus enables greater performance.[37] Compared to what is thought of as a two and a half stage rocket, like the Delta IV Heavy, the Falcon Heavy central core can operate at full thrust and yet still be left with a nearly full fuel load after booster separation.

After the side cores are released, the center engine in each side core will continue to burn for a few seconds in order to control the trajectory of the side booster.[38][39]

All three cores of the Falcon Heavy arrange the engines in a structural form SpaceX calls Octaweb, aimed at streamlining the manufacturing process,[40] and each core will include four extensible landing legs,[39] which will be used for vertical-landing once the post-mission technology development effort is completed.[41]

Second stage[edit]

The upper stage is powered by a single Merlin 1D engine modified for vacuum operation, with an expansion ratio of 117:1 and a nominal burn time of 345 seconds. For added reliability of restart, the engine has dual redundant pyrophoric igniters (TEA-TEB).[4]

The interstage, which connects the upper and lower stage for Falcon 9, is a carbon fiber aluminum core composite structure. Stage separation occurs via reusable separation collets and a pneumatic pusher system. The Falcon 9 tank walls and domes are made from aluminum lithium alloy. SpaceX uses an all-friction stir welded tank. The second stage tank of Falcon 9 is simply a shorter version of the first stage tank and uses most of the same tooling, material and manufacturing techniques. This approach reduces manufacturing costs during vehicle production.[4]

Reusable technology development[edit]

Although not a part of the initial Falcon Heavy design, SpaceX is doing parallel development on a reusable rocket launching system that is intended to be extensible to the Falcon Heavy, first to the booster stage and ultimately to the second stage as well.

Early on, SpaceX had expressed hopes that both rocket stages would eventually be reusable.[42] More recently, in 2011, SpaceX announced a funded development program to build and fly a reusable launch system that will ultimately bring a first stage back to the launch site in minutes — and a second stage back to the launch pad, following orbital realignment with the launch site and atmospheric reentry, in up to 24 hours — with both stages designed to be available for reuse within "single-digit hours" after return.[43] As of February 2012, design is complete on the system for "bringing the rocket back to launchpad using only thrusters."[43]

The reusable launch system technology is under consideration for both the Falcon 9 and the Falcon Heavy. It is particularly well suited to the Falcon Heavy where the two outer cores separate from the rocket much earlier in the flight profile, and are therefore both moving at a slower velocity at the initial separation event.[43]

As of March 2013, the publicly announced aspects of the SpaceX reusable rocket technology development effort include an active test campaign of the low-altitude, low-speed Grasshopper vertical takeoff, vertical landing (VTVL) technology demonstrator rocket,[44][45] and a high-altitude, high-speed Falcon 9 post-mission booster-return test campaign where—beginning in late-2013, with the sixth overall flight of Falcon 9—every Falcon 9 first stage which was instrumented and equipped as a controlled descent test vehicle to accomplish propulsive-return over-water tests.[41]

SpaceX has indicated that the Falcon Heavy payload performance to Geosynchronous transfer orbit (GTO) will be reduced by addition of the reusable technology, but would fly at much lower launch price. With full reusability on all three booster cores, GTO payload will be 7,000 kg (15,000 lb). If only the two outside cores fly as reusable cores while the center core is expendable, GTO payload would be approximately 14,000 kg (31,000 lb).[46] Falcon 9 will do satellites up to roughly 3.5 tonnes, with full reusability of the boost stage, and Falcon Heavy will do satellites up to 7 tonnes with full reusability of the all three boost stages," [Musk] said, referring to the three Falcon 9 booster cores that will comprise the Falcon Heavy's first stage. He also said Falcon Heavy could double its payload performance to GTO "if, for example, we went expendable on the center core."

Development funding and competitive position[edit]

The Falcon Heavy is being developed with private capital. No government financing is being provided for its development.[9]

SpaceX current prices for space launch are already the lowest in the industry.[47] If SpaceX is able to successfully complete development on its SpaceX reusable rocket technology and return booster stages to the launch pad for reuse, a new economically-driven Space Age could result.[9][48]

Launcher specifications[edit]

The initial version of the Falcon Heavy will use the same extended-length stages[clarification needed] as the Falcon 9 v1.1 with Merlin 1D engines.

Item Falcon Heavy
Stage 0 2 boosters with 9 × Merlin 1D engines each[6][49]
Stage 1 9 × Merlin 1D[6]
Stage 2 1 × Merlin 1D
Height
(max; m)
68.4[6][7]
Diameter
(m)
11.6 m (38 ft), composed of three 3.7 m (12 ft) Falcon 9 v1.1 cores aligned side by side[7]
Initial thrust
(kN)
17,615[7]
Takeoff weight
(tonnes)
1,463[7]
Fairing diameter
(outer; m)
5.2[7][15]
Payload
(LEO; kg)
53,000[6][36][50] (if crossfeed not used : 45,360)[51]
Payload
(GTO; kg)
21,200[7][50]
12,000[15] (when announced in 2011)
Payload
(to Mars; kg)
13,200[7]
Price
(Mil. USD)
77.1-135 in 2013,[50] 83-128 in 2012,[15] 80-125 in 2011[6]
minimal Price/kg
(LEO; USD)
2,200 ($1,000/lb)[14]
minimal Price/kg
(GTO; USD)
12,970 up to 6,400 kg[15][dated info]
Success ratio
(successful/total)
N/A

Testing[edit]

A new, partially underground test stand is being built at the SpaceX Rocket Development and Test Facility in McGregor, Texas specifically to test the triple cores and twenty seven rocket engines of the Falcon Heavy.[52]

Launches and scheduled launches[edit]

Flight Number Date & Time (GMT) Payload Customer Outcome Remarks
1 2014[53] Falcon Heavy Demo Flight 1 SpaceX Scheduled Hardware is expected to arrive at the Vandenberg AFB in 2014[53]
2014 Not yet announced Scheduled First FH flight from Cape Canaveral (was originally projected to be 2013).[13]
2015 Green Propellant Infusion Mission NASA Scheduled[54][55] The cost of the program is about $45 million.[56] GPIM is a secondary payload on Falcon Heavy so will launch along with an FH primary payload on a single launch.
2016[citation needed] STP-2[30] DoD Scheduled The mission will support the EELV certification process for the Falcon Heavy.[citation needed]
2017 Communications satellite[28] Intelsat[29] Scheduled First Commercial mission for Falcon Heavy.[29] First launch to a Geostationary transfer orbit for Falcon Heavy.[28]

See also[edit]

References[edit]

  1. ^ Tybor, Frank SpaceX: Access to Space in the Commercial Era, February 12, 2013, Speech.
  2. ^ Clark, Stephen (11 March 2012). "SpaceX eyes shuttle launch pad for heavy-lift rocket". Spaceflight Now. Retrieved 2012-03-12. 
  3. ^ "SpaceX Falcon 9 Upper Stage Engine Successfully Completes Full Mission Duration Firing" (Press release). SpaceX. March 10, 2009. 
  4. ^ a b c d "Falcon 9 Overview". SpaceX. 8 May 2010. 
  5. ^ a b Svitak, Amy (2014-03-10). "SpaceX Says Falcon 9 To Compete For EELV This Year". Aviation Week. Retrieved 2014-03-11. "We need to find three additional cores that we could produce, send them through testing and then fly without disrupting our launch manifest,' Musk says. 'I'm hopeful we'll have Falcon Heavy cores produced approximately around the end of the year. But just to get through test and qualification, I think it's probably going to be sometime early next year when we launch.'" 
  6. ^ a b c d e f g h Clark, Stephen (April 5, 2011). "SpaceX enters the realm of heavy-lift rocketry". Spaceflight Now. Retrieved 2012-06-04. 
  7. ^ a b c d e f g h i j "Falcon Heavy". SpaceX. Retrieved 2013-12-04. 
  8. ^ HSF Final Report: Seeking a Human Spaceflight Program Worthy of a Great Nation, October 2009, Review of U.S. Human Spaceflight Plans Committee, p. 64-66: "5.2.1 The Need for Heavy Lift ... require a “super heavy-lift” launch vehicle ... range of 25 to 40 mt, setting a notional lower limit on the size of the super heavy-lift launch vehicle if refueling is available ... this strongly favors a minimum heavy-lift capacity of roughly 50 mt ..."
  9. ^ a b c Boozer, R.D. (2014-03-10). "Rocket reusability: a driver of economic growth". The Space Review 2014. Retrieved 2014-03-25. 
  10. ^ Energia lift off thrust was 7,800,000 lbf, Falcon Heavy is projected to be 3,969,000 per http://www.spacex.com/falcon-heavy
  11. ^ Testimony of Elon Musk (May 5, 2004). "Space Shuttle and the Future of Space Launch Vehicles". U.S. Senate. 
  12. ^ Sietzen, Frank, Jr. (2001-03-18). "Spacelift Washington: International Space Transportation Association Faltering; The myth of $10,000 per pound". spaceref.com. Retrieved 2013-08-08. 
  13. ^ a b c "SpaceX announces launch date for FH". 2011-04-05. Retrieved 2011-08-25. "First launch from our Cape Canaveral launch complex is planned for late 2013 or 2014." 
  14. ^ a b Upgraded Spacex Falcon 9.1.1 will launch 25% more than old Falcon 9 and bring price down to $4109 per kilogram to LEO, NextBigFuture, 22 Mar 2013.
  15. ^ a b c d e f "Space Exploration Technologies Corporation - Falcon Heavy". SpaceX. 2011-12-03. Retrieved 2011-12-03. 
  16. ^ [1]. Retrieved 2014-03-25.
  17. ^ a b c d "SpaceX Press Conference". SpaceX. Retrieved 2011-04-16. 
  18. ^ a b "US co. SpaceX to build heavy-lift, low-cost rocket". Reuters. 5 April 2011. Archived from the original on 5 April 2011. Retrieved 2011-04-05. 
  19. ^ "Launch Manifest". SpaceX. Archived from the original on 2012-12-23. Retrieved 2012-12-12. 
  20. ^ "Launch Manifest". SpaceX. Archived from the original on 2014-01-10. Retrieved 2014-01-10. 
  21. ^ a b Foust, Jeff (2013-04-01). "The great state space race". The Space Review. Retrieved 2013-04-03. 
  22. ^ Svitak, Amy (2014-03-05). "SpaceX to Compete for Air Force Launches This Year". Aviation Week. Retrieved 2013-03-12. 
  23. ^ "SpaceX Brochure". Retrieved 2011-06-14. 
  24. ^ "Red Dragon" (PDF). Feasibility of a Dragon-derived Mars lander for scientific and human-precursor investigations. 8m.net. October 31, 2011. Retrieved 2012-05-14. 
  25. ^ "Capabilities & Services". SpaceX. 2013. Retrieved 2014-03-25. 
  26. ^ "Discovery Program". NASA Discovery Program Office. Retrieved 2013-08-03. 
  27. ^ Wall, Mike (2011-07-31). "'Red Dragon' Mission Mulled as Cheap Search for Mars Life". SPACE.com. Retrieved 2011-07-31. "This so-called "Red Dragon" mission, which could be ready to launch by 2018, would carry a cost of about $400 million or less. ... developing the Red Dragon concept as a potential NASA Discovery mission, a category that stresses exploration on the relative cheap. ... NASA will make another call for Discovery proposals in 18 months or so... If Red Dragon is selected in that round, it could launch toward Mars in 2018. ... Assuming that $425 million cap [for NASA Discovery missions] is still in place, Red Dragon could come in significantly under the bar. We'd have money left over to do some science." 
  28. ^ a b c "SpaceX Announces First Commercial Contract For Launch In 2013". Red Orbit. 2012-05-30. Retrieved 2012-12-15. 
  29. ^ a b c "Intelsat Signs First Commercial Falcon Heavy Launch Agreement With SpaceX" (Press release). SpaceX. 2012-05-29. Retrieved 2012-12-16. 
  30. ^ a b Lindsay, Clark (2012-12-05). "SpaceX awarded 2 EELV-Class missions from the USAF". NewSpace Watch. Retrieved 2012-12-15. (subscription required (help)). 
  31. ^ Clark, Stephen (2012-12-06). "SpaceX books first two launches with U.S. military". NewSpace Watch. Retrieved 2012-12-31. 
  32. ^ "SpaceX Announces Launch Date for the World's Most Powerful Rocket". Spaceref.com. Retrieved 2011-04-10. 
  33. ^ "Saturn C-3". Encyclopedia Astronautica. Retrieved 2012-06-08. 
  34. ^ Harwood, William (2011-04-05). "World's biggest private space rocket planned". CBS. Retrieved 2011-04-05. 
  35. ^ "SpaceX Unveils Plans To Be World’s Top Rocket Maker". Aviation Week and Space Technology. 2011-08-11. Retrieved 2011-08-07. "Revealing several new details of the 1D, Tom Mueller, propulsion engineering vice president, says the engine is designed to produce 155,000 lb. vacuum thrust and have a chamber pressure at “the sweet spot” of roughly 1,410 psia. “We’ve also increased the nozzle expansion ratio to 16 [compared with 14.5 on the Merlin 1C],” says Mueller, who adds that the initial engine “is doing better than we hoped.” The engine is designed for an Isp (specific impulse) of 310 sec. and has a thrust-to-weight ratio of 160:1. “We took structure off the engine to make it lighter. The engine we shipped [for test] to Texas was a development engine and hopefully the production engines will be even better.”" 
  36. ^ a b (this technique is nick-named 'Asparagus staging') Strickland, John K., Jr. (September 2011). "The SpaceX Falcon Heavy Booster". National Space Society. Retrieved 2012-11-24. 
  37. ^ a b "SpaceX Announces Launch Date for the World's Most Powerful Rocket". SpaceX. 2011-04-05. Retrieved 2011-04-05. 
  38. ^ Nield, George C. (April 2014). Draft Environmental Impact Statement: SpaceX Texas Launch Site (Report). 1. Federal Aviation Administration, Office of Commercial Space Transportation ". pp. 2–3. http://1.usa.gov/YtxBzo. "The center core engines are throttled down after liftoff and up to two engines may be shut down as the vehicle approaches maximum acceleration. After the side boosters drop off, the center core engines throttle back up to full thrust. The center engine in each side core continues to burn for a few seconds after separation to control the descent trajectorie of the side boosters."
  39. ^ a b "Landing Legs". SpaceX News. 2013-04-12. Retrieved 2013-08-02. "The Falcon Heavy first stage center core and boosters each carry landing legs, which will land each core safely on Earth after takeoff. After the side boosters separate, the center engine in each will burn to control the booster’s trajectory safely away from the rocket. The legs will then deploy as the boosters turn back to Earth, landing each softly on the ground. The center core will continue to fire until stage separation, after which its legs will deploy and land it back on Earth as well. The landing legs are made of state-of-the-art carbon fiber with aluminum honeycomb. The four legs stow along the sides of each core during liftoff and later extend outward and down for landing." 
  40. ^ "Octaweb". SpaceX News. 2013-04-12. Retrieved 2013-08-02. "The Octaweb structure of the nine Merlin engines improves upon the former 3x3 engine arrangement. The Octaweb is a metal structure that supports eight engines surrounding a center engine at the base of the launch vehicle. This structure simplifies the design and assembly of the engine section, streamlining our manufacturing process." 
  41. ^ a b Lindsey, Clark (2013-03-28). "SpaceX moving quickly towards fly-back first stage". NewSpace Watch. Retrieved 2013-03-29. (subscription required (help)). 
  42. ^ Musk ambition: SpaceX aim for fully reusable Falcon 9, NASAspaceflight.com, 2009-01-12, accessed 2010-06-03
  43. ^ a b c Simberg, Rand (2012-02-08). "Elon Musk on SpaceX’s Reusable Rocket Plans". Popular Mechanics. Retrieved 2012-02-07. 
  44. ^ Klotz, Irene (2011-09-27). "A rocket that lifts off — and lands — on launch pad". MSNBC. Retrieved 2011-11-23. 
  45. ^ Mohney, Doug (2011-09-26). "SpaceX Plans to Test Reusable Suborbital VTVL Rocket in Texas". Satellite Spotlight. Retrieved 2011-11-23. 
  46. ^ Svitak, Amy (2013-03-05). "Falcon 9 Performance: Mid-size GEO?". Aviation Week. Archived from the original on 2014-03-25. Retrieved 2014-03-25. 
  47. ^ Belfiore, Michael (December 9, 2013). "The Rocketeer". Foreign Policy; Feature article. Retrieved 2013-12-11. 
  48. ^ Messier, Doug (January 14, 2014). "Shotwell: Reusable Falcon 9 Would Cost $5 to $7 Million Per Launch". Parabolic Arc. Retrieved 2014-01-15. 
  49. ^ Clark, Stephen (May 29, 2012). "SpaceX signs first commercial customer for Falcon Heavy". Spaceflight Now. Retrieved 2012-06-04. 
  50. ^ a b c "SpaceX Capabilities and Services". webpage. SpaceX. 2013. Retrieved 2014-03-25. 
  51. ^ "SPACEX ANNOUNCES LAUNCH DATE FOR THE WORLD'S MOST POWERFUL ROCKET". spacex. April 5, 2011. 
  52. ^ "Falcon Heavy Test Stand". Retrieved 2013-05-06. 
  53. ^ a b "SpaceX Launch Manifest". SpaceX. Retrieved 2013-06-27. 
  54. ^ "About Green Propellant Infusion Mission (GPIM)". NASA. 2014. Retrieved 2014-02-26. 
  55. ^ "Green Propellant Infusion Mission (GPIM)". Ball Aerospace. 2014. Retrieved 2014-02-26. 
  56. ^ Casey, Tina (19 July 2013). "NASA Sets Its Sights On $45 Million Green Fuel Mission". Clean Technica. Retrieved 2014-02-27. 

External links[edit]