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SpaceX Confirms Stage Bump On Demoflight 2
Casper WY (SPX) Mar 23, 2007 SpaceX chief Elon Musk has confirmed that Stages 1 and 2 collided on the second flight of the company�s Falcon 1 small launch vehicle this week, and is an issue that will need to be dealt with. Musk has also revealed that Stage 1 was not recovered, due in part to a nonfunctioning GPS tracking device on the stage at liftoff. As described previously on SpaceDaily.com, the onboard video shows the Stage 2 exit cone running into the integral interstage on top of Stage 1 during staging separation, with an obvious "bump" effect on the motion between the large first stage and fully fueled second. "Yes, the stage sep bump will obviously need to be addressed, however it does not appear to have caused damage," Musk said. "The reason we chose a niobium metal skirt is that it is resilient to bumps vs C-C [carbon-carbon composite] nozzle, which is brittle and may crack." According to the SpaceX website, "An impact from orbital debris or during stage separation would simply dent the metal, but have no meaningful effect on engine performance." Musk himself asserted that "There is substantial inflation pressure on the nozzle, so, even if the skirt dented, it would undent immediately after ignition." Musk said that the ring seen falling off the cone soon after staging was an intentionally discarded ground support. "[The ring] is just two bonded on titanium half circles used to stabilize the nozzle during shipping and pad operations. It is supposed to come off when the nozzle heats up, as we don't want to carry it to orbit." Regarding the second stage Kestrel engine, Musk said "The surprise was how cool the nozzle ended up being. It is capable of glowing white hot and was only a little bit red in places. We clearly have far more film cooling than is actually needed." Separately, Musk said that SpaceX failed to find the recoverable Stage 1 after the launch. "Unfortunately, the GPS locator attached to the first stage was not working during the countdown. Since it was not mission critical, we launched without it and relied upon the sonar beacon and strobe light. "Unlike the Shuttle booster recovery ship, Kwaj [Kwajalein] range safety requires that we be quite far outside the projected landing point, which means the recovery ship would take a few hours at minimum to reach the landing point. By the time our ship reached the estimated landing point, the crew could not find the stage. It is unknown at this time whether the parachute opened correctly or not. "The SpaceX pricing does not assume reusability, so this does not break our business model, but of course long term getting this right matters a lot for cost reduction." In addition to the launch economics, a recovered Stage 1 would also have allowed engineers to examine the hardware and potentially learn about system durability and reusability. On telemetry outages, Musk said, "We had some blips in telemetry, but were able to obtain a data feed for almost the entire flight time. The stage rotation caused the signal/noise to vary from strong to weak, as the antenna position changed and the distance from the receiving dish increased. However, with some additional work, we managed to reconstruct almost all the data." Musk defended his description of the flight as a success. "The primary goal of this test flight was to learn enough to ensure that when we launch a satellite on the next flight, it has a high likelihood of success. We believe we do, therefore the objective was successfully achieved." Musk also dismissed the importance of reaching orbit on the flight. "Whether the stage reached full orbital velocity or not is largely beside the point. It would have performed no useful function there," he stated. The vehicle carried two small NASA technology payloads, and was to demonstrate ejection of an aluminum ring simulating a satellite deployment. SpaceX has stated that it plans no additional test flights before its next commercial flights this year, which will separately loft experimental satellites for the US Navy and a Malaysian / South Korean team. Musk said that SpaceX would publish a detailed update on the launch on its website by next week, noting it was "so very important that we have time to properly digest the data." Related Links Space X Rocket Science News at Space-Travel.Com Rocket Science News at Space-Travel.Com
Falcon 1 Video Suggests Stage Collision
Casper WY (SPX) Mar 22, 2007The video of the SpaceX "Demoflight 2" launch this week in the South Pacific appears to show a serious staging anomaly that, if confirmed, would likely need to be addressed before the next flight of the Falcon 1 vehicle. In response to an email, Gwynne Shotwell, SpaceX Vice President of Business Development, disagreed with the anomaly assessment. "There was no anomaly there. We knew the second stage would kick a bit after separation. There was no contact from initial look." |
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