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, a space-transportation startup company founded by entrepreneur and PayPal founder Elon Musk 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.

Two test launches of the Falcon 1 have been conducted in 2006 and 2007, neither of which achieved orbit. According to SpaceX the second test launch was in their view however largely successful and Falcon 1 will now obtain operational status.

Design, components and launch sequence

According to SpaceX the Falcon 1 is designed to minimize price per launch for low-Earth-orbit satellites, increase reliability, optimize flight environment and time to launch. It is also intended to verify components and structural design concepts that will be reused in the Falcon 9.

At launch of the vehicle, the main engine of the first stage (Merlin) 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. The first-stage burn lasts about 2:49 minutes. Stage separation is accomplished with explosive bolts and a pneumatically actuated pusher system. The first stage returns by parachute to a water landing and is recovered for reuse, while the second stage is not reusable. The second stage with its Kestrel engine is ignited after stage separation and burns for another six minutes and inserts the payload into a low Earth orbit.

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.

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 log

Flight No	Date & Time (GMT)	Launch Site	Payload/Customer	Outcome	Remarks
1	24 March 2006, 22:30 (25 March, 09:30 local)	Omelek	FalconSat–2/DARPA	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/DARPA	Failure	Successful first stage burn and transition to second stage, maximum altitude 289 km Harmonic oscillation at T+5 minutes Premature engine shutdown at T+7 min 30 s Failed to reach orbit Failed to recover first stage Claimed to be a "Partial success" as it gathered enough data for operational flights
Scheduled Launches
	September 2007	Omelek	TacSat-1/OSD	Scheduled
	December 2007	Omelek	Razaksat/ATSB (Malaysia)	Scheduled
	First Quarter 2009	Vandenberg AFB	Unknown/SpaceDev	Scheduled
	Third Quarter 2009	Vandenberg AFB	Unknown/MDA Corporation	Scheduled
	Fourth Quarter 2009	Vandenberg AFB	Unknown/Swedish Space Corp.	Scheduled

Launches

First test flight

File:Falcon 1 fire.jpeg

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

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

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. Impact 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, but 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 test flight

Events leading to launch

The second test flight was originally scheduled for January, but was delayed due to problems with the second stage. Before the January launch date, SpaceX had stated earlier potential launch dates, moving from September 2006 to November and December. In December the launch was 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 attempt on March 21, 2007 was aborted at 00:05 GMT at the last second before launch and after the engine had ignited. It was however decided that another launch should be made the same day. The rocket was launched successfully at 01:10 GMT on 21 March 2007 with a DemoSat payload for DARPA and NASA. The rocket performed well during the first stage burn. However, during staging, the interstage fairing on the top of the first stage bumped the second stage engine bell . The bump occurred as the second stage nozzle exited the interstage, with the first stage rotating much higher than expected (a rotation rate of about 2.5 deg/sec vs. expected rate of 0.5 deg/sec maximum), thereby making contact with the niobium nozzle of the second stage. Elon Musk reported that the bump did not appear to have caused damage, and that the reason why they chose a niobium skirt instead of carbon-carbon was to prevent problematic damage in the event of such incidents. Shortly after second stage ignition, a stabilization ring detached from the engine bell as designed. At around T+4:20, a circular coning oscillation began that increased in amplitude until video was lost. At T+5:01, the vehicle started to roll and telemetry ended. According to Elon Musk, the second stage engine shut down at T+7.5 minutes due to a roll control issue. Sloshing of propellant in the LOX tank increased oscillation. This oscillation would normally have been dampened by the Thrust Vector Control system in the second stage, but the bump to the second nozzle during separation caused an overcompensation in the correction. The rocket continued to within one minute of its desired location, and also managed to deploy the satellite mass simulator ring. While the webcast video ended prematurely, SpaceX was able to retrieve telemetry for the entire flight. The status of the first stage is unknown; it was not recovered due to problems with a nonfunctioning GPS tracking device. The rocket reached a final altitude of 289 km (156 miles) and a final velocity of 5.1 km/s, compared to 7.5 km/s needed for orbit.

SpaceX reaction and proposed remedy of problems

SpaceX characterized the test flight as a success, having flight proven over 95% of Falcon 1's systems. Their primary objectives for this launch were to test responsive launch procedures and gather data. According to Musk, the SpaceX team intends to have both a diagnosis and solution vetted by third party experts. Musk believes the slosh issue can be corrected by adding baffles to the second stage LOX tank and adjusting the control logic. Furthermore, the Merlin shutdown transient can be addressed by initiating shutdown at a much lower thrust level, albeit at some risk to engine reusability. The SpaceX team intends to work the problem to avoid a reoccurrence as they change over into the operational phase for Falcon 1.

Further missions

The third flight will also be from Omelek, carrying the Naval Research Laboratory TacSat-1. This will be the first "operational" flight of Falcon 1. 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 September, 2007. This flight is also scheduled to carry a space burial payload including cremated remains of James Doohan, Gordon Cooper, and others.)

Private funding

The Falcon 1 rocket is a largely privately funded and developed orbital launch vehicle. The only other orbital launch vehicle, that has been claimed to be privately funded and developed is the Pegasus (rocket) first launched in 1990. Orbital Sciences, the manufacturer and operator of the Pegasus claims that it is the first privately developed rocket able to reach orbit . Other sources have claimed that the Falcon 1 is the first privately funded orbital space vehicle that would be capable of reaching orbit.

While the development of Falcon 1 was privately funded, both Falcon 1 test launches have been paid for by the U.S. Deparment of Defense under a program that evaluates new US launch vehicles suitable for use by DARPA.

Pricing

SpaceX is one of the few launch system operators that communicate launch prices to the public. Falcon 1 has been advertised as costing $5.9 million as early as 2005. In 2006 until 2007 the quoted price of the rocket when operational was $6.7 million. Most recently SpaceX has announced new prices for the Falcon 1 and an enhanced Falcon 1e, which should go operational in 2009. The price for Falcon 1 is now set at $7 million and the price for Falcon 1e at $8.5 million. SpaceX notes that small discounts may be available for multi-launch contracts.

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

Elon Musk has reportedly said the Air Force may evict SpaceX from its Vandenberg launch site because of safety concerns expressed by United Launch Alliance, which launches the Atlas V rocket from a neighboring launch site at SLC-3W.

• Cape Canaveral Air Force Station Launch Complex 40.
• Kwajalein Atoll (Omelek Island), part of the Reagan Test Site
• Kodiak Island
• Wallops Island

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