Falcon 1

Falcon 1

Falcon 1 rocket in front of the FAA building in Washington DC.
Function	Orbital launch vehicle
Manufacturer	SpaceX
Size
Height	21.3 m (70 ft)
Diameter	1.7 m (5.5 ft)
Mass	38,555 kg (85,000 lb)
Stages	2
Capacity
Payload to LEO	670 kg (1480 lb)
Payload to SSO	430 kg (990 lb)
Launch history
Status	Active
Launch sites	Omelek Island SLC-3W Vandenberg AFB LC-36 Cape Canaveral
Total launches	2
Failure(s)	2
First flight	March 24, 2006 22:30 GMT
First stage
Engines	1 SpaceX Merlin
Thrust	454 kN (102,000 lbf)
Specific impulse	255 s (sea level) (2.6 kN·s/kg)
Burn time	169 seconds
Propellant	RP-1/LOX
Second stage
Engines	1 SpaceX Kestrel
Thrust	31 kN (7,000 lbf)
Specific impulse	327 s (vacuum) (3.2 kN·s/kg))
Burn time	378 seconds
Propellant	RP-1/LOX

The Falcon 1 is a partially reusable launch system, designed and manufactured by SpaceX to provide commercial launch-to-space services. The two-stage-to-orbit rocket uses Lox/RP-1 for both stages, the first powered by a single Merlin engine and the second powered by a single Kestrel engine.

It is the world's first privately funded and developed liquid-fueled orbital launch vehicle, and is currently priced at US$6.7 million.

Design

The Falcon 1 is designed to minimize price per launch for low-Earth-orbit satellites. It is also intended to verify components and structural design concepts that will be reused in the Falcon 9. The first stage returns by parachute to a water landing and is recovered for reuse, while the second stage is not reusable.

First stage

First-stage view of the Merlin engine.

The first stage is made from friction-stir-welded aluminum alloy. It employs a common bulkhead between the LOX and RP-1 tanks, as well as flight pressure stabilization. It can be transported safely without pressurization (like the heavier Delta II isogrid design) but gains additional strength when pressurized for flight (like the Atlas II, which cannot be transported unpressurized). The resulting design has the highest mass fraction of any current first stage. The parachute system, built by Irvin Para­chute Corp­oration, uses a high-speed drogue chute and a main chute. Due to problems with LOX boil-off during the launch of the first vehicle, future vehicles are expected to have foam insulation applied to the exterior of the LOX tank.

Until SpaceX gains experience with reusing the first stage, the quoted price presupposes that no reuse of the first stage is taking place. If and when the recycling process is perfected, the launch price may be expected to drop.

Second stage

The second stage tanks are built with a cryogenic-compatible aluminum–lithium alloy. The helium pressurization system pumps propellant to the engine, supplies pressurized gas for the attitude control thrusters, and is used for zero-g propellant accumulation prior to engine restart. The pressure tanks are made by Arde corporation and are the same as those used in the Delta IV. They consist of an inconel shell wrapped by a composite.

Launch sequence

Launch sequence (maiden flight example); time scale is in seconds.

The main engine is ignited and throttled to full power while the launcher is restrained and all systems are verified by the flight computer. If the systems are operating correctly, the rocket is released and clears the tower in about seven seconds. First-stage burn lasts about 2:49 minutes. Stage separation is accomplished with explosive bolts and a pneumatically actuated pusher system. See the launch sequence timeline below for more details.

Launch sites

The Falcon 1 can be launched from five different sites, with the first two flights lifting off from Kwajalein.

• Vandenberg Air Force Base, Pad 3W
• Cape Canaveral Air Force Station, Launch Complex 36
• Kwajalein Atoll (Omelek Island), part of the Reagan Test Site
• Kodiak Island
• Wallops Island

First flight failure

File:Falcon 1 fire.jpeg

The Merlin engine on fire during launch of the first Falcon 1 flight.

The maiden flight of the Falcon 1 was launched on Saturday, 24 March 2006 at 22:30 UTC. It ended in failure about a minute into the flight due to a fuel line leak and subsequent fire. The launch took place from the SpaceX spaceport at Omelek Island in the Marshall Islands.

The launch was postponed several times due to various technical issues with the new vehicle. Scheduling conflicts with a Titan IV launch at Vandenburg also caused delays and resulted in the launch moving to the Reagan Test Site in the Kwajalein Atoll. The first launch attempt on 19 December 2005 was scrubbed when a faulty valve caused a vacuum in the first stage fuel tank which sucked inward and caused structural damage. After replacing the first stage, Falcon 1 launched Saturday, 25 March 2006 at 09:30 local time. The DARPA payload was the United States Air Force Academy’s FalconSAT–2, which would have measured space plasma phenomena.

The vehicle had a noticeable rolling motion after liftoff, as shown on the launch video, rocking back and forth a bit, and then at T+26 seconds rapidly pitched over. Impacted occurred at T+41 seconds onto a dead reef about 250 feet from the launch site. The FalconSAT–2 payload separated from the booster and landed on the island, with damage reports varying from slight to significant.

SpaceX initially attributed the fire to an improperly tightened fuel-line nut. A later review by DARPA found that the nut was properly tightened, since its locking wire was still in place, and had failed due to corrosion.

SpaceX implemented numerous changes to the rocket design and software to prevent this type of failure from reoccurring, including stainless steel to replace aluminum hardware and pre-liftoff computer checks that increased by a factor of thirty. .

Second flight

File:Fairing gone.jpg

Fairing separation at Falcon 1 Demo Flight 2 (fairing separation took place at T+03:15 in an altitude of around 117 km). You can see the Kestrel engine of the second stage running and the two halves of the fairing vanishing into the atmosphere behind at T+03:20.

The second mission was launched at 01:10 GMT on 21 March 2007 from Omelek Island with a DemoSat payload for DARPA and NASA. It was originally scheduled for January, but was delayed due to problems with the second stage. It was then rescheduled for 9 March, but delayed because of range availability issues caused by a Minuteman III test flight which would re-enter over Kwajelen. The launch attempt on 19 March was delayed 45 minutes from 23:00 GMT due to a data relay issue, and then scrubbed one minute and two seconds before launch at 23:45 due to a computer issue, whereby the safety computer incorrectly detected a transmission failure due to a hardware delay of a few milliseconds in the process. The 20 March attempt was delayed 65 minutes, from an originally planned time of 23:00 due to a problem with communications between one of the NASA experiments in the payload, and the TDRS system. The launch was aborted at 00:05 GMT on 21 March, at the last second before launch, and after the engine had ignited, however the decision to attempt another launch the same day was taken.

The rocket performed well during the first stage burn. At stage separation, the spent first stage struck the second stage engine bell. There was no visible damage. A circular oscillation began that increased in amplitude until video was lost. At around T+5 minutes, the vehicle started to spin and telemetry ended. According to Elon Musk, the second stage engine shut down due to a roll control issue. The status of the recovery of the first stage is unknown.

Further missions

The third flight will also be from Omelek, carrying a Naval Research Laboratory Tacsat and a Space Services Incorporated space burial payload (which will include remains of James Doohan, Gordon Cooper, and others). This was intended to be the original maiden flight, but delays in a Titan IV launch from the Vandenberg complex had a knock-on effect to SpaceX, . This mission was originally scheduled for 2005, from Vandenberg AFB, but delays due to the Titan launch, and problems with the rocket pushed it into mid-2006. It was then delayed further, as the failure of the maiden flight necessitated a second test mission. It is currently scheduled for mid 2007.

Launch log

Flight No	Date & Time (GMT)	Launch Site	Payload	Outcome	Remarks
1	24 March 2006, 22:30 (25 March, 09:30 local)	Omelek	FalconSat–2	Failure	Engine failure at T+25 seconds loss of vehicle; payload recovered (but damaged beyond repair)
2	21 March 2007 01:10 (13:10 local)	Omelek	DemoSat	Did not reach orbit	Successful first stage burn and transition to second stage, maximum altitude approx. 300 km Apparent loss of control at T+5 minutes Loss of signal at T+5 mins, 5 secs Failed to reach orbit
Scheduled Launches
	July 2007	Omelek	TacSat-1	Scheduled
	3rd Quarter 2007	Omelek	RazakSAT	Scheduled
	November 2007	Omelek	Mars Gravity Biosatellite	Scheduled
	Mid 2008	Vandenberg AFB	Various	Scheduled
	Late 2008	Vandenberg AFB		Scheduled
	Late 2009	Vandenberg AFB		Scheduled

External links

• SpaceX Falcon 1 details page
• Space Services Inc. space burial page
• Maiden launch details at SpaceFlightNow
• "SpaceX rocket fails first flight". BBC News. 24 March 2006. {{cite news}}: Check date values in: |date= (help)
• Damage puts first SpaceX rocket launch on hold, Spaceflight Now, 19 December 2005