Falcon 1 Flight 4

infobox spacecraft


Caption = Falcon 1 Flight 4 lifting off from Omelek
Name = Ratsatcite web|url=http://planet4589.org/space/jsr/latest.html |title= Issue 601|accessdate= 2008-09-29|last=McDowell|first=Jonathan|date= 2008-09-26|format= html|publisher= Jonathan's Space Report|language= English]
Carrier_Rocket = Falcon 1
Launch_Site = Omelek
Launch = 23:15 GMT, 28 September 2008
Organisation = SpaceX
Orbit_regime = LEO
Mass = convert|165|kg|lbcite web|url=http://www.spacex.com/F1-004.php|title=Falcon 1 Flight 4|last=Musk|first=Elon|date=2008-09-27|publisher=SpaceX|language=English|accessdate=2008-09-28]
Inclination = 9.35°
Apoapsis = convert|643|km|mi
Periapsis = convert|621|km|mi
Mission_Type = DemoSat/Boilerplate

Falcon 1 Flight 4 was a test flight of the SpaceX Falcon 1 rocket, which was launched on 28 September 2008, at 23:15 GMT from Omelek Island, part of the Kwajalein Atoll in the Marshall Islands.cite web|url=http://www.spaceflightnow.com/falcon/004/status.html|title=Mission Status Center|last=Ray|first=Justin|date=2008-09-28|publisher=Spaceflight Now|language=English|accessdate=2008-09-28] It was Falcon 1's first successful launch, and the first of any privately-funded, liquid-propelled carrier rocket.

As a result of the failure of three previous launches, the rocket carried a non-functional boilerplate spacecraft. cite web|url=http://www.space.com/news/080806-spacex-falcon1-update.html|title=SpaceX Traces Third Rocket Failure to Timing Error|last=Malik|first=Tariq|coauthors=Berger, Brian|date=2008-08-06|publisher=Space.com|language=English|accessdate=2008-09-28] The boilerplate spacecraft is a 165-kilogram (363-pound) payload mass simulator, known as Ratsat, which remained bolted to the second stage of the carrier rocket after reaching low Earth orbit.cite web|url=http://www.spaceflightnow.com/falcon/004/080927preview.html|title=SpaceX to launch its fourth Falcon 1 rocket on Sunday|last=Clark|first=Stephen|date=2008-09-27|publisher=Spaceflight Now|language=English|accessdate=2008-09-28] It has a hexagonal prism shape, 1.5 m (5 ft) long.cite web|url=http://www.spacex.com/press.php?page=20080928|title=Press Release: SpaceX Successfully Launches Falcon 1 to Orbit] SpaceX co-founder Elon Musk estimates that Ratsat will remain in orbit for between five and ten years before burning up in the atmosphere.

The rocket followed the same trajectory as the previous flight, which failed to place the Trailblazer, NanoSail-D, PreSat and Explorers spacecraft into orbit. No major changes were made to the rocket, other than increasing the time between first stage burnout and second stage separation. This minor change addressed the failure seen on the previous flight, recontact between the first and second stages, by dissipating residual thrust in the first stage engine before separating them. [Cite news | id=issn|0362-4331 | last = Schwartz | first = John | title = Private Company Launches Its Rocket Into Orbit | work = The New York Times | accessdate = 2008-09-29 |date = 2008-09-29 | url = http://www.nytimes.com/2008/09/29/science/space/29launch.html?_r=1&ref=us&oref=slogin]

Preparations

When the fourth flight was first announced in August 2008, shortly after the third flight failed, it was planned for launch in September. The rocket that was used to conduct the test flight was originally built to launch the RazakSAT satellite. The test flight was introduced into the launch schedule because Astronautic Technology (M) Sdn. Bhd (ATSB)cite web|url=http://acronyms.thefreedictionary.com/ATSB|title=ATSB|work=The Free Dictionary|publisher=Farlex|accessdate=2008-10-05] required a successful flight to be conducted before RazakSAT could be launched.

The schedule left very little time for modifications and testing. The rocket was shipped to the company's testing facilities in Texas where, after less than 24 hours, it was certified for launch. SpaceX chartered a United States Air Force C-17 flight on 3–4 September to carry both stages of the rocket 9,700 km (6,000 mi) to the launch facilities at the Kwajalein Atoll. The Falcon 1 rocket was successfully test-fired on 20 September. Launch preparations on 23 September led the ground crew to replace part of a pipeline supplying liquid oxygen to the second stage "Kestrel" engine. This work delayed the launch to 28 September.

Launch

The launch occurred at 23:15 GMT on 28 September, 15 minutes into a five-hour launch window. If the launch had been scrubbed, it could have been conducted during the same window until 1 October. Nine minutes and 31 seconds after launch, the second stage engine shut down, after the vehicle reached orbit. The initial orbit was reported to be about 330 x 650 km. [cite web|last=Clark|first=Stephen|title=Sweet Success at Last for Falcon 1 Rocket|date=2008-09-28|publisher=Spaceflight Now|url=http://www.spaceflightnow.com/falcon/004/index.html|accessdate=2008-09-30] Following a coast period, the second stage restarted, and performed a successful second burn, resulting in a final orbit of 621 x 643 km x 9.35°.

ee also

* 2008 in spaceflight

References