Grasshopper is an experimental technology-demonstrator, suborbital reusable launch vehicle (RLV), a vertical takeoff, vertical landing (VTVL) rocket, built to support development and test of a subset of the technologies required for the SpaceX reusable rocket launching system.
Grasshopper was announced in 2011 and began low-altitude, low-velocity hover/landing testing in 2012. The initial Grasshopper test vehicle—the 32 metres (106 ft)-tall Grasshopper v1.0—made eight successful test flights in 2012 and 2013 before being retired. A second Grasshopper test vehicle—the larger and more capable Grasshopper v1.1—is currently being built and will be used for testing at higher altitudes and supersonic speeds; the first low-altitude flight test is planned for December 2013.
Grasshopper is being developed and tested by Space Exploration Technologies (SpaceX) in order to assist development of the reusable Falcon 9 and reusable Falcon Heavy rockets, which will require vertical landings of the near-empty Falcon 9 and Falcon Heavy first-stage booster tanks and engine assemblies.
Grasshopper is one element of the multi-element, incremental SpaceX reusable rocket launching system test program, a program that includes Grasshopper testing both in low-altitude, low-velocity situations at the SpaceX Texas test site and high-altitude, mid-velocity testing of the larger second-generation Grasshopper test vehicle with all nine engines at Spaceport America in New Mexico, as well as high-altitude, high-speed controlled-descent tests of post-mission (spent) Falcon 9 booster stages on Falcon 9 missions beginning in September 2013.
The Grasshopper technology demonstrator first became known publicly in the third quarter of 2011, when space journalists first wrote about it after analyzing US government space launch regulatory documents.
Shortly thereafter, SpaceX confirmed the existence of the test vehicle development program, and projected it would begin the Grasshopper flight test program in 2012. Grasshopper began flight testing in September 2012 with a brief, three-second hop at the company's Texas test site, followed by a second hop in November 2012 with an 8-second flight that took the testbed approximately 5.4 metres (18 ft) off the ground, and a third flight in December 2012 of 29 seconds duration, with extended hover under rocket engine power, in which it ascended to an altitude of 40 metres (130 ft) before descending under rocket power to come to a successful vertical landing.
From the announcement in 2011, SpaceX has achieved each of the schedule milestones that they publicly announced. SpaceX said in February 2012 that they were planning several vertical-takeoff, vertical-landing (VTVL) test flights during 2012, and confirmed in June 2012 that they continued to plan to make the first test flight within the next couple of months. Updated photos of the rocket on the test pad appeared in a news article on 11 Sep 2012, They achieved first flight on September 21, 2012.
Beginning in October 2012, SpaceX discussed development of a second generation Grasshopper test VTVL vehicle, one that would have lighter-weight landing legs that fold up on the side of the rocket, would have a different engine bay and would be nearly 50% longer than the first Grasshopper vehicle. In May 2013, they announced that the higher-altitude, higher-velocity part of the Grasshopper flight test program would be done at Spaceport America—and not at the Federal Government's adjacent White Sands Missile Range facility as previously planned —near Las Cruces, New Mexico, and signed a three-year lease for land and facilities at the recently operational spaceport. SpaceX indicated in May 2013 that they do not yet know how many jobs will move from McGregor, Texas to New Mexico.
Two versions of the Grasshopper test vehicle are under development, the 106-foot tall Grasshopper v1.0 and the 160-foot tall Grasshopper v1.1.
When Grasshopper was first disclosed in September 2011, the rocket was described to consist of "a Falcon 9 first stage tank, a single Merlin-1D engine, four steel landing legs and a support structure, plus other pressurization tanks attached to the support structure" and will stand at 106 feet (32 m) tall. Photos released in September 2012 reveal the test article landing gear to be considerably more sophisticated, with the tank and rocket engine as previously described.
Grasshopper can land on Earth with the accuracy of a helicopter. and has made seven test flights through August 2013. On August 13, 2013, the Grasshopper vehicle successfully completed a "divert test", flying to 250 meters altitude, completing a 100 meter lateral maneuver, and then returning to land on the pad.
Grasshopper v1.0 made its eighth, and final, test flight on October 7, 2013, flying to an altitude of 744 metres (2,441 ft) (0.46 miles) before making its eighth successful landing. The v1.0 test vehicle is now retired.
Grasshopper v1.1—also known as Falcon 9 Reusable (F9R) development vehicle —was initially announced in October 2012, when SpaceX indicated that a second Grasshopper vehicle with fold-up landing legs would be built on the longer Falcon 9 v1.1 platform.
In March 2013, it was announced that the v1.1 Grasshopper suborbital flight vehicle would be constructed out of the Falcon 9 v1.1 first-stage tank that had been used for qualification testing in Texas at the SpaceX Rocket Development and Test Facility prior to March. It was to be rebuilt as the next Grasshopper with landing legs similar to those to be used in actual launches. In May 2013, the design for the retractable landing leg was shown to be a telescoping piston on an A-frame. The total span of the four legs will be approximately 18 metres (60 ft), and the landing gear will weigh less than 2,100 kilograms (4,600 lb); the deployment system will use high-pressure Helium.
Test plans call for the v1.1 Grasshopper to be high-altitude flight tested only at Spaceport America, New Mexico, at altitudes up to approximately 91,000 metres (300,000 ft). SpaceX began constructing a 30 by 30 metres (98 × 98 ft) pad at Spaceport America in May 2013, 7 kilometres (4.3 mi) southwest of the spaceport's main campus, and will lease the pad for US$6,600 per month plus US$25,000 per Grasshopper flight. As of May 2013[update], the spaceport administrator expected SpaceX to be operational at the Spaceport sometime between October 2013 and February 2014, and that is the time that the lease payments were expected to begin.
In August 2013, SpaceX announced that the Grasshopper v1.1 test vehicle would fly in New Mexico with all nine engines of the fully loaded Falcon 9-R, whereas Grasshopper v1.0 had flown exclusively with only a single Merlin 1D engine in place, the center engine which is planned to be used to complete the last phase of the deceleration and landing. The testing is expected to start in New Mexico only after low-altitude initial flight tests of the Grasshopper v1.1 are accomplished in Texas at the SpaceX Rocket Development and Test Facility, sometime after October 2013.
Flight test program
Flight tests will include subsonic and supersonic testing.
Releases of public information in 2011 indicated that the subsonic tests would occur at SpaceX McGregor, Texas facility in three phases, at maximum flight altitudes of 670 to 11,500 feet (200 to 3,500 m), for durations of 45 to 160 seconds (0.75 to 2.67 min). At the time, testing was expected to take up to three years and the initial FAA permit allows up to 70 suborbital launches per year. A half-acre concrete launch facility was constructed to support the test flight program. In September 2012, SpaceX announced that they have requested FAA approval to increase the altitude of some of the initial test flights.
The first flight test, called a "brief hop" by journalist Clark Lindsey, occurred on 21 Sep 2012. The flight of the near-empty rocket stage was to a height of 6 feet (1.8 m) and lasted 3 seconds.
Looking forward to the next year, CEO Musk said in November 2012: "Over the next few months, we’ll gradually increase the altitude and speed. ... I do think there probably will be some craters along the way; we’ll be very lucky if there are no craters. Vertical landing is an extremely important breakthrough — extreme, rapid reusability." Then in March 2013 Musk said that SpaceX hoped to reach hypersonic speed before the end of 2013. In May 2013, SpaceX moved the location of the higher-altitude, higher-velocity flight testing to Spaceport America, from the previous plan to do that testing at White Sands Missile Range.
On the 29 Sep 2013 webcast for Falcon 9 Flight 6, SpaceX indicated that there are several additional flights of the Grasshopper v1.0 at the Texas test site planned, in addition to a series of higher-altitude tests planned for Grasshopper v1.1 test vehicle at the New Mexico Spaceport America test site.
The first flight test of the Grasshopper v1.1 test vehicle is planned for December 2013.
Several test phases were identified by SpaceX in 2011 regulatory documentation:
Phase 1: The goal of Phase 1 is to verify the Grasshopper RLV’s overall ability to perform a VTVL mission. During a Phase 1 test, the Grasshopper RLV would be launched and ascend to 240 feet above ground level and then throttle down in order to descend, landing back on the pad approximately 45 seconds after liftoff.
Phase 2: There would be slightly less propellant loaded, a different thrust profile, and the maximum altitude would be increased to 670 feet, still below Class E Airspace. The mission duration during Phase 2 is again approximately 45 seconds.
Phase 3: The goal of Phase 3—as outlined in the 2011 FAA documents for the McGregor, Texas location—is to verify the Grasshopper RLV’s ability to perform a VTVL mission at higher altitudes and higher ascent speeds and descent speeds. To achieve this, the maximum mission altitude, envisioned in the 2011 documents, would be increased from 670 feet incrementally up to 11,500 feet. The altitude test sequence likely would be 1,200 feet; 2,500 feet; 5,000 feet; 7,500 feet; and 11,500 feet. The maximum test duration would be approximately 160 seconds. The scope of the testing of Grasshopper v1.1 at the New Mexico Spaceport America facility has not yet been made public.
The first VTVL flight test vehicle—Grasshopper v1.0, built on a Falcon 9 v1.0 first-stage tank—made a total of eight test flights in 2012–2013. All flights were from the McGregor, Texas test facility.
|Test #||Date (year-month-day)||Highest altitude||Duration||Remarks|
|1||2012-09-21||6 feet (1.8 m)||3 seconds|
|2||2012-11-01||17.7 feet (5.4 m)||8 seconds|
|3||2012-12-17||131 feet (40 m)||29 seconds||First flight to include the cowboy mannequin|
|4||2013-03-07||262 feet (80 m)||34 seconds||Touchdown thrust-to-weight ratio greater than one|
|5||2013-04-17||820 feet (250 m)||61 seconds||Demonstrated ability to maintain stability in wind|
|6||2013-06-14||1,066 feet (325 m)||68 seconds||New navigation sensor suite tested; needed on the F9-R for precision landing|
|7||2013-08-13||820 feet (250 m)||60 seconds||Also performed 330 feet (100 m) lateral maneuver before returning to the pad.|
|8||2013-10-07||2,441 feet (744 m)||79 seconds||Final flight of Grasshopper v1.0. Vehicle retired after the flight.|
The second VTVL flight test vehicle—Grasshopper v1.1, built on the much longer Falcon 9 v1.1 first-stage tank, and with retractable landing legs—is planned to make its first test flight in December 2013.
|Test #||Date (year-month-day)||Highest altitude||Duration||Remarks|
|1||2013-12||First low-altitude flight is planned for December 2013, at the Texas test site.|
Related over-water flight testing
In March 2013, SpaceX announced that, beginning with the first flight of the stretch version of the Falcon 9 launch vehicle—the sixth flight overall of Falcon 9 (then anticipated for summer 2013), every first stage would be instrumented and equipped as a controlled descent test vehicle. SpaceX intends to test propulsive-return over-water until a return to the launch site and a powered landing is accomplished successfully. They cautioned the public to expect several failures before a successful landing is achieved. For the first flight of the v1.1 Falcon 9 in 2013, after stage separation, the first stage booster would do a deceleration burn to slow it down and then a second burn just before it reached the water. When all of the over-water testing is complete, they intend to fly back to the launch site and land propulsively, perhaps as early as mid-2014. The over-water tests will occur in both the Pacific and Atlantic oceans, south of Vandenberg Air Force Base and east of Cape Canaveral Air Force Station.
SpaceX does not expect a successful booster recovery in the first several powered-descent tests.
The first flight test of the booster controlled descent was on 29 September 2013. The test was successful—with substantial test milestones achieved and a great deal of engineering test data—but the booster was not successfully recovered from the ocean. SpaceX tested a large amount of new technology on the flight, and that—coupled with the technology advancements made on the Grasshopper technology demonstrator—they now believe they have "all the pieces of the puzzle, ... [they] were able to successfully transition from vacuum through hypersonic, through supersonic, through transonic, and light the engines all the way and control the stage all the way through—we have all the pieces necessary to achieve a full recovery of the boost stage." Musk said "the next attempt to recover the Falcon 9 first stage will be on the fourth flight of the upgraded rocket. This would be third commercial Dragon cargo flight to ISS", scheduled for 2014.
|Wikimedia Commons has media related to Grasshopper (rocket).|
- Falcon (rocket family)
- SpaceX reusable rocket launching system—Grasshopper is one component of the test program for the overall reusable launch vehicle technology that SpaceX is developing.
- SpaceX private launch site
- Vertical takeoff, vertical landing rockets
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- Video of 1st test launch, 21 Sep 2012
- Video of 2nd test launch, 1 Nov 2012
- Video of 3rd test launch H=40m, 17 Dec 2012
- Video of 4th test launch H=80m, 8 Mar 2013
- Video of 5th test launch H=250m, 17 Apr 2013
- Video of 6th test launch H=325m, 14 June 2013
- Video of 7th test launch H=250m L=100m, 13 August 2013
- Video of 8th test launch H=744m, 7 Oct 2013